Sample Exchange Evaluation (SEE) Report - Phase II

International Nuclear Information System (INIS)

Winters, W.I.

1994-01-01

This report describes the results from Phase II of the Sample Exchange Evaluation (SEE) Program, a joint effort to compare analytical laboratory performance on samples from the Hanford Site's high-level waste tanks. In Phase II, the program has been expanded to include inorganic constituents in addition to radionuclides. Results from Phase II that exceeded 20% relative percent difference criteria are identified

Cross-sample entropy of foreign exchange time series

Science.gov (United States)

Liu, Li-Zhi; Qian, Xi-Yuan; Lu, Heng-Yao

2010-11-01

The correlation of foreign exchange rates in currency markets is investigated based on the empirical data of DKK/USD, NOK/USD, CAD/USD, JPY/USD, KRW/USD, SGD/USD, THB/USD and TWD/USD for a period from 1995 to 2002. Cross-SampEn (cross-sample entropy) method is used to compare the returns of every two exchange rate time series to assess their degree of asynchrony. The calculation method of confidence interval of SampEn is extended and applied to cross-SampEn. The cross-SampEn and its confidence interval for every two of the exchange rate time series in periods 1995-1998 (before the Asian currency crisis) and 1999-2002 (after the Asian currency crisis) are calculated. The results show that the cross-SampEn of every two of these exchange rates becomes higher after the Asian currency crisis, indicating a higher asynchrony between the exchange rates. Especially for Singapore, Thailand and Taiwan, the cross-SampEn values after the Asian currency crisis are significantly higher than those before the Asian currency crisis. Comparison with the correlation coefficient shows that cross-SampEn is superior to describe the correlation between time series.

Direct determination of uranium in soil, rock, ore and biological samples by laser-induced fluorometry

International Nuclear Information System (INIS)

Li Qingzhen; Zhang Yanan

1993-03-01

A laser-induced fluorometric method with modified J-22 anti-interferent fluorescent reagent for directly determining the uranium in soil, rock, ore, geochemical, biological and other samples has been studied. The effects of external ions and dilution law of sample are examined in detail. A method for correcting inner effect is proposed. A mixed solution of 0.25% NaOH-10% J-22 is prepared which can be added to the sample cuvette for direct measurement without any pre-adjustment of acidity. Therefore, it is much simpler for operation and reduces the loss and contamination of uranium. By changing the laser fluorometer sensitivity (400 ∼ 200), up to 3000 ng uranium in the cuvette can be detected. Thus, both analytical accuracy and detectable range are improved. This method is simple, rapid, accurate and applicable to various uranium-bearing samples. The detection limit is better than 0.05 μgU/g. The relative standard deviation is ≤+-5% for the rock reference samples of 0.95, 84.8, 669 and 7240 μgU/g

Kinetics of exchange of a tracer in soil and clay samples

Energy Technology Data Exchange (ETDEWEB)

Zanotti, J C; Facetti, J F [Asuncion Nacional Univ. (Paraguay). Inst. de Ciencias

1971-01-01

The kinetics of exchange of a Na tracer in soil and clay samples, provides with a reliable and convenient method for the determination of the different soil fraction ahd their CEC values, In addition, the analysis of the exchanges curves can be used for the identification of the clay present in the soil.

Kinetics of exchange of a tracer in soil and clay samples

International Nuclear Information System (INIS)

Zanotti, J.C.; Facetti, J.F.

1971-01-01

The kinetics of exchange of a Na tracer in soil and clay samples, provides with a reliable and convenient method for the determination of the different soil fraction ahd their CEC values, In addition, the analysis of the exchanges curves can be used for the identification of the clay present in the soil

Automated Sample Exchange Robots for the Structural Biology Beam Lines at the Photon Factory

International Nuclear Information System (INIS)

Hiraki, Masahiko; Watanabe, Shokei; Yamada, Yusuke; Matsugaki, Naohiro; Igarashi, Noriyuki; Gaponov, Yurii; Wakatsuki, Soichi

2007-01-01

We are now developing automated sample exchange robots for high-throughput protein crystallographic experiments for onsite use at synchrotron beam lines. It is part of the fully automated robotics systems being developed at the Photon Factory, for the purposes of protein crystallization, monitoring crystal growth, harvesting and freezing crystals, mounting the crystals inside a hutch and for data collection. We have already installed the sample exchange robots based on the SSRL automated mounting system at our insertion device beam lines BL-5A and AR-NW12A at the Photon Factory. In order to reduce the time required for sample exchange further, a prototype of a double-tonged system was developed. As a result of preliminary experiments with double-tonged robots, the sample exchange time was successfully reduced from 70 seconds to 10 seconds with the exception of the time required for pre-cooling and warming up the tongs

Replica exchange with solute tempering: A method for sampling biological systems in explicit water

Science.gov (United States)

Liu, Pu; Kim, Byungchan; Friesner, Richard A.; Berne, B. J.

2005-09-01

An innovative replica exchange (parallel tempering) method called replica exchange with solute tempering (REST) for the efficient sampling of aqueous protein solutions is presented here. The method bypasses the poor scaling with system size of standard replica exchange and thus reduces the number of replicas (parallel processes) that must be used. This reduction is accomplished by deforming the Hamiltonian function for each replica in such a way that the acceptance probability for the exchange of replica configurations does not depend on the number of explicit water molecules in the system. For proof of concept, REST is compared with standard replica exchange for an alanine dipeptide molecule in water. The comparisons confirm that REST greatly reduces the number of CPUs required by regular replica exchange and increases the sampling efficiency. This method reduces the CPU time required for calculating thermodynamic averages and for the ab initio folding of proteins in explicit water. Author contributions: B.J.B. designed research; P.L. and B.K. performed research; P.L. and B.K. analyzed data; and P.L., B.K., R.A.F., and B.J.B. wrote the paper.Abbreviations: REST, replica exchange with solute tempering; REM, replica exchange method; MD, molecular dynamics.*P.L. and B.K. contributed equally to this work.

Colorimetric Determination of the Iron(III)-Thiocyanate Reaction Equilibrium Constant with Calibration and Equilibrium Solutions Prepared in a Cuvette by Sequential Additions of One Reagent to the Other

Science.gov (United States)

Nyasulu, Frazier; Barlag, Rebecca

2011-01-01

The well-known colorimetric determination of the equilibrium constant of the iron(III-thiocyanate complex is simplified by preparing solutions in a cuvette. For the calibration plot, 0.10 mL increments of 0.00100 M KSCN are added to 4.00 mL of 0.200 M Fe(NO[subscript 3])[subscript 3], and for the equilibrium solutions, 0.50 mL increments of…

Mechanical design and simulation of an automatized sample exchanger

International Nuclear Information System (INIS)

Lopez, Yon; Gora, Jimmy; Bedregal, Patricia; Hernandez, Yuri; Baltuano, Oscar; Gago, Javier

2013-01-01

The design of a turntable type sample exchanger for irradiation and with a capacity for up to 20 capsules was performed. Its function is the automatic sending of samples contained in polyethylene capsules, for irradiation in the grid position of the reactor core, using a pneumatic system and further analysis by neutron activation. This study shows the structural design analysis and calculations in selecting motors and actuators. This development will improve efficiency in the analysis, reducing the contribution of the workers and also the radiation exposure time. (authors).

Hanford high level waste: Sample Exchange/Evaluation (SEE) Program

International Nuclear Information System (INIS)

King, A.G.

1994-08-01

The Pacific Northwest Laboratory (PNL)/Analytical Chemistry Laboratory (ACL) and the Westinghouse Hanford Company (WHC)/Process Analytical Laboratory (PAL) provide analytical support services to various environmental restoration and waste management projects/programs at Hanford. In response to a US Department of Energy -- Richland Field Office (DOE-RL) audit, which questioned the comparability of analytical methods employed at each laboratory, the Sample Exchange/Exchange (SEE) program was initiated. The SEE Program is a selfassessment program designed to compare analytical methods of the PAL and ACL laboratories using sitespecific waste material. The SEE program is managed by a collaborative, the Quality Assurance Triad (Triad). Triad membership is made up of representatives from the WHC/PAL, PNL/ACL, and WHC Hanford Analytical Services Management (HASM) organizations. The Triad works together to design/evaluate/implement each phase of the SEE Program

Development of sample exchange robot PAM-HC for beamline BL-1A at the photon factory

Energy Technology Data Exchange (ETDEWEB)

Hiraki, Masahiko, E-mail: masahiko.hiraki@kek.jp [Mechanical Engineering Center, Applied Research Laboratory, KEK (High Energy Accelerator Research Organization), 1-1 Oho, Tsukuba, Ibaraki 305-0801 Japan (Japan); Department of Accelerator Science, SOKENDAI (the Graduate University for Advanced Studies), 1-1 Oho, Tsukuba, Ibaraki 305-0801 Japan (Japan); Matsugaki, Naohiro; Yamada, Yusuke; Senda, Toshiya [Structural Biology research Center, Institute of Materials Structure Science, KEK (Japan); Department of Materials Structure Science, SOKENDAI (Japan)

2016-07-27

A macromolecular crystallography beamline, BL-1A, has been built at the Photon Factory (PF) for low energy experiments and has been operational since 2010. We have installed a sample exchange robot, PAM (PF Automated Mounting system), similar to other macromolecular crystallography beamlines. However, following the installation of a helium chamber to reduce the absorption of the diffraction signal by air, we developed a new sample exchange robot to replace PAM. The new robot, named PAM-HC (Helium Chamber), is designed with the goal of minimizing leakage of helium gas from the chamber. Here, the PAM-HC hardware and the flow of its movement are described. Furthermore, measurements of temperature changes during sample exchange are presented in this paper.

Development of sample exchange robot PAM-HC for beamline BL-1A at the photon factory

International Nuclear Information System (INIS)

Hiraki, Masahiko; Matsugaki, Naohiro; Yamada, Yusuke; Senda, Toshiya

2016-01-01

A macromolecular crystallography beamline, BL-1A, has been built at the Photon Factory (PF) for low energy experiments and has been operational since 2010. We have installed a sample exchange robot, PAM (PF Automated Mounting system), similar to other macromolecular crystallography beamlines. However, following the installation of a helium chamber to reduce the absorption of the diffraction signal by air, we developed a new sample exchange robot to replace PAM. The new robot, named PAM-HC (Helium Chamber), is designed with the goal of minimizing leakage of helium gas from the chamber. Here, the PAM-HC hardware and the flow of its movement are described. Furthermore, measurements of temperature changes during sample exchange are presented in this paper.

Simulated Tempering Distributed Replica Sampling, Virtual Replica Exchange, and Other Generalized-Ensemble Methods for Conformational Sampling.

Science.gov (United States)

Rauscher, Sarah; Neale, Chris; Pomès, Régis

2009-10-13

Generalized-ensemble algorithms in temperature space have become popular tools to enhance conformational sampling in biomolecular simulations. A random walk in temperature leads to a corresponding random walk in potential energy, which can be used to cross over energetic barriers and overcome the problem of quasi-nonergodicity. In this paper, we introduce two novel methods: simulated tempering distributed replica sampling (STDR) and virtual replica exchange (VREX). These methods are designed to address the practical issues inherent in the replica exchange (RE), simulated tempering (ST), and serial replica exchange (SREM) algorithms. RE requires a large, dedicated, and homogeneous cluster of CPUs to function efficiently when applied to complex systems. ST and SREM both have the drawback of requiring extensive initial simulations, possibly adaptive, for the calculation of weight factors or potential energy distribution functions. STDR and VREX alleviate the need for lengthy initial simulations, and for synchronization and extensive communication between replicas. Both methods are therefore suitable for distributed or heterogeneous computing platforms. We perform an objective comparison of all five algorithms in terms of both implementation issues and sampling efficiency. We use disordered peptides in explicit water as test systems, for a total simulation time of over 42 μs. Efficiency is defined in terms of both structural convergence and temperature diffusion, and we show that these definitions of efficiency are in fact correlated. Importantly, we find that ST-based methods exhibit faster temperature diffusion and correspondingly faster convergence of structural properties compared to RE-based methods. Within the RE-based methods, VREX is superior to both SREM and RE. On the basis of our observations, we conclude that ST is ideal for simple systems, while STDR is well-suited for complex systems.

Development of a system using the library of the Genie spectroscopy software and exchange of samples

International Nuclear Information System (INIS)

Lapolli, Andre L.; Munita, Casimiro S.

2011-01-01

One the great difficulties in using the NAA method is in regards to the time that the operator spends exchanging the samples after each measurement. It becomes a big problem in routine analyses when various chemical elements are determined and then each sample must be measured at different decay times. The application of the automatic sample exchanger reduces the time analysis by several hours and reduces the tedious manual operation. Then, the effective use of NAA depends on the availability of a suitable automatic sample changer. There are some systems that are sold commercially, however many laboratories can not acquire them because they are costly. This paper presents altered programs the G2KNAA.REX, which created a screen making possible automatic or manual acquisitions by calling the old program NAAACQ.rex for the procurement manual and the new program NAAACQ2.rex for automatic requisitions. In conclusion, as can be seen in the program lines, the synchronization to automation, which unites the three systems (the computer, the Canberra Set, the sample exchanger) is done in a timely manner. The system was tested and is functioning in a satisfactory manner. (author)

Victor Brauner. Atrapulsion, peinture à la caséine sur toile présentant un important réseau de craquelures en cuvette

OpenAIRE

Pingeot, Cristina Cojocaru

2014-01-01

Atrapulsion est une peinture à la caséine sur toile de Victor Brauner (datée de 1938). L’altération majeure est constituée par la présence d’un réseau de craquelures généralisé, avec écailles en cuvette et en soulèvement. L’artiste a utilisé pour cette peinture des matières inadaptées à la peinture sur toile. L’œuvre a reçu un traitement de refixage avec une résine synthétique qui a laissé des résidus brillants en surface. L’élaboration du diagnostic a nécessité la réalisation d’essais de mod...

Acoustically levitated droplets: a contactless sampling method for fluorescence studies.

Science.gov (United States)

Leiterer, Jork; Grabolle, Markus; Rurack, Knut; Resch-Genger, Ute; Ziegler, Jan; Nann, Thomas; Panne, Ulrich

2008-01-01

Acoustic levitation is used as a new tool to study concentration-dependent processes in fluorescence spectroscopy. With this technique, small amounts of liquid and solid samples can be measured without the need for sample supports or containers, which often limits signal acquisition and can even alter sample properties due to interactions with the support material. We demonstrate that, because of the small sample volume, fluorescence measurements at high concentrations of an organic dye are possible without the limitation of inner-filter effects, which hamper such experiments in conventional, cuvette-based measurements. Furthermore, we show that acoustic levitation of liquid samples provides an experimentally simple way to study distance-dependent fluorescence modulations in semiconductor nanocrystals. The evaporation of the solvent during levitation leads to a continuous increase of solute concentration and can easily be monitored by laser-induced fluorescence.

Determination of 129I in environmental samples by AMS and NAA using an anion exchange resin disk

Science.gov (United States)

Suzuki, Takashi; Banba, Shigeru; Kitamura, Toshikatsu; Kabuto, Shoji; Isogai, Keisuke; Amano, Hikaru

2007-06-01

We have developed a new extraction method for the measurement of 129I by accelerator mass spectrometry (AMS) utilizing an anion exchange resin disk. In comparison to traditional methods such as solvent extraction and ion exchange, this method provides for simple and quick sample handling. This extraction method was tested on soil, seaweed and milk samples, but because of disk clogging, the milk samples and some of the seaweed could not be applied successfully. Using this new extraction method to prepare samples for AMS analysis produced isotope ratios of iodine in good agreement with neutron activation analysis (NAA). The disk extraction method which take half an hour is faster than previous techniques, such as solvent extraction or ion exchange which take a few hours. The combination of the disk method and the AMS measurement is a powerful tool for the determination of 129I. Furthermore, these data will be available for the environmental monitoring before and during the operation of a new nuclear fuel reprocessing plant in Japan.

Determination of 129I in environmental samples by AMS and NAA using an anion exchange resin disk

International Nuclear Information System (INIS)

Suzuki, Takashi; Banba, Shigeru; Kitamura, Toshikatsu; Kabuto, Shoji; Isogai, Keisuke; Amano, Hikaru

2007-01-01

We have developed a new extraction method for the measurement of 129 I by accelerator mass spectrometry (AMS) utilizing an anion exchange resin disk. In comparison to traditional methods such as solvent extraction and ion exchange, this method provides for simple and quick sample handling. This extraction method was tested on soil, seaweed and milk samples, but because of disk clogging, the milk samples and some of the seaweed could not be applied successfully. Using this new extraction method to prepare samples for AMS analysis produced isotope ratios of iodine in good agreement with neutron activation analysis (NAA). The disk extraction method which take half an hour is faster than previous techniques, such as solvent extraction or ion exchange which take a few hours. The combination of the disk method and the AMS measurement is a powerful tool for the determination of 129 I. Furthermore, these data will be available for the environmental monitoring before and during the operation of a new nuclear fuel reprocessing plant in Japan

Characterization of primary coolant purification system samples for assay of spent ion exchanger radionuclide inventor

International Nuclear Information System (INIS)

Sajin Prasad, S.; Pant, Amar; Sharma, Ranjit; Pal, Sanjit

2018-01-01

The primary coolant system water of a research reactor contains various fission and activation products and the water is circulated continuously through ion exchange resin cartridges, to reduce the radioactive ionic impurity present in it. The coolant purification system comprises of an ion exchange cooler, two micro filters, and a battery of six ion exchanger beds, associated valves, piping and instrumentation (Heavy water System Operating manual, 2014). The spent cartridge is finally disposed off as active solid waste which contains predominantly long lived fission and activation products. The heavy water coolant is also used to cool the structural assemblies after passing through primary heat exchanger and a metallic strainer, which accumulates the fission and activation products. When there is a reduction of coolant flow through these strainers, they are removed for cleaning and decontamination. This paper describes the characterization of ion exchange resin samples and liquid effluent generated during ultra sonic decontamination of strainer. The results obtained can be used as a methodology for the assay of the spent ion exchanger cartridges radionuclide inventory, during its disposal

Enhanced Sampling in Molecular Dynamics Using Metadynamics, Replica-Exchange, and Temperature-Acceleration

Directory of Open Access Journals (Sweden)

Cameron Abrams

2013-12-01

Full Text Available We review a selection of methods for performing enhanced sampling in molecular dynamics simulations. We consider methods based on collective variable biasing and on tempering, and offer both historical and contemporary perspectives. In collective-variable biasing, we first discuss methods stemming from thermodynamic integration that use mean force biasing, including the adaptive biasing force algorithm and temperature acceleration. We then turn to methods that use bias potentials, including umbrella sampling and metadynamics. We next consider parallel tempering and replica-exchange methods. We conclude with a brief presentation of some combination methods.

Replica Exchange Gaussian Accelerated Molecular Dynamics: Improved Enhanced Sampling and Free Energy Calculation.

Science.gov (United States)

Huang, Yu-Ming M; McCammon, J Andrew; Miao, Yinglong

2018-04-10

Through adding a harmonic boost potential to smooth the system potential energy surface, Gaussian accelerated molecular dynamics (GaMD) provides enhanced sampling and free energy calculation of biomolecules without the need of predefined reaction coordinates. This work continues to improve the acceleration power and energy reweighting of the GaMD by combining the GaMD with replica exchange algorithms. Two versions of replica exchange GaMD (rex-GaMD) are presented: force constant rex-GaMD and threshold energy rex-GaMD. During simulations of force constant rex-GaMD, the boost potential can be exchanged between replicas of different harmonic force constants with fixed threshold energy. However, the algorithm of threshold energy rex-GaMD tends to switch the threshold energy between lower and upper bounds for generating different levels of boost potential. Testing simulations on three model systems, including the alanine dipeptide, chignolin, and HIV protease, demonstrate that through continuous exchanges of the boost potential, the rex-GaMD simulations not only enhance the conformational transitions of the systems but also narrow down the distribution width of the applied boost potential for accurate energetic reweighting to recover biomolecular free energy profiles.

Note: Low-temperature scanning tunneling microscope with detachable scanner and reliable transfer mechanism for tip and sample exchange.

Science.gov (United States)

Ge, Weifeng; Wang, Jihao; Wang, Junting; Zhang, Jing; Hou, Yubin; Lu, Qingyou

2017-12-01

A homebuilt low-temperature scanning tunneling microscope (STM) featuring a detachable scanner based on a double slider design, along with a reliable transfer mechanism for tip and sample exchange, is present. The coarse motor is decoupled from the scanner, which prevents the motor instabilities including vibrations and drifts from entering the tip-sample loop and thus improves the performance of the STM. In addition, in situ exchange of tips and samples can be implemented easily and reliably using a winch-type transfer mechanism. Atomically resolved images on graphite are demonstrated to show the performance of the proposed STM.

Midday stomatal closure in Mediterranean type sclerophylls under simulated habitat conditions in an environmental chamber : II. Effect of the complex of leaf temperature and air humidity on gas exchange of Arbutus unedo and Quercus ilex.

Science.gov (United States)

Tenhunen, J D; Lange, O L; Braun, M

1981-08-01

Shrubs of the Mediterranean sclerophyllous species Arbutus unedo and Quercus ilex were studied under simulated habitat conditions in an environmental chamber. Temperature, humidity, and light intensity were altered stepwise to simulate diurnal changes in conditions similar to those measured in an evergreen macchia in Sobreda, Portugal. Leaves were enclosed in cuvettes which reproduced the growth chamber climate and which allowed measurement of gas exchange. Increasing atmospheric stress in the form of higher temperature and lower humidity on successive days gradually results in midday depression of transpiration rate and net photosynthesis rate of leaves due to midday stomatal closure.

Semiautomatic exchanger of samples for carry out neutron activation analysis; Intercambiador semiautomatico de muestras para realizar analisis por activacion neutronica

Energy Technology Data Exchange (ETDEWEB)

Aguilar H, F.; Quintana C, G. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Torres R, C. E.; Mejia J, J. O., E-mail: fortunato.aguilar@inin.gob.mx [Instituto Tecnologico de Toluca, Av. Tecnologico s/n, Ex-Rancho La Virgen, Metepec, Estado de Mexico (Mexico)

2015-09-15

In this paper the design methodology and implementation of a semiautomatic exchanger of samples for the Analysis Laboratory by Neutron Activation of the Reactor department is presented. Taking into account the antecedents, the necessities of improvement are described, as well as the equipment that previously contained the Laboratory. The project of the semiautomatic exchanger of samples was developed at Instituto Nacional de Investigaciones Nucleares, with its own technology to increase independence from commercial equipment. Each element of the semiautomatic exchanger of samples is described both in the design phase as construction. The achieved results are positive and encouraging for the fulfillment of the proposed objective that is to increase the capacity of the Laboratory. (Author)

Order parameter free enhanced sampling of the vapor-liquid transition using the generalized replica exchange method.

Science.gov (United States)

Lu, Qing; Kim, Jaegil; Straub, John E

2013-03-14

The generalized Replica Exchange Method (gREM) is extended into the isobaric-isothermal ensemble, and applied to simulate a vapor-liquid phase transition in Lennard-Jones fluids. Merging an optimally designed generalized ensemble sampling with replica exchange, gREM is particularly well suited for the effective simulation of first-order phase transitions characterized by "backbending" in the statistical temperature. While the metastable and unstable states in the vicinity of the first-order phase transition are masked by the enthalpy gap in temperature replica exchange method simulations, they are transformed into stable states through the parameterized effective sampling weights in gREM simulations, and join vapor and liquid phases with a succession of unimodal enthalpy distributions. The enhanced sampling across metastable and unstable states is achieved without the need to identify a "good" order parameter for biased sampling. We performed gREM simulations at various pressures below and near the critical pressure to examine the change in behavior of the vapor-liquid phase transition at different pressures. We observed a crossover from the first-order phase transition at low pressure, characterized by the backbending in the statistical temperature and the "kink" in the Gibbs free energy, to a continuous second-order phase transition near the critical pressure. The controlling mechanisms of nucleation and continuous phase transition are evident and the coexistence properties and phase diagram are found in agreement with literature results.

Method for determining immunochemical substances

International Nuclear Information System (INIS)

O'connor, J.

1980-01-01

Drawing a method for detecting and measuring a predetermined specifically-bindable immunochemical substance in a liquid sample in a cuvette, comprising the steps of: (A) providing, in an immunoassay technique for the liquid sample in said cuvette, a component comprising a suspension of particles which may be agglutinated or insolubilized in relationship to the presence and concentration of the immunochemical substance in the sample; and (B) determining the presence and concentration of the immunochemical substance by measuring the electromagnetic radiation transmission properties of the sample using a calibrated radiation-measuring apparatus, said apparatus comprising: (1) a suitable electromagnetic radiation source capable of providing radiation at wavelengths equal to or less than the mean diameter of said particles; (2) means for concentrating and collimating radiation from the electromagnetic radiation source to form a beam; (3) means for filtering the beam to (I) eliminate radiation having wavelengths greater than the means diameter of the particles and (II) transmit radiation, which radiation has a range, whereby the upper wavelength is equal to or below the mean diameter of the particles, and the range is of at least about 100nm; (4) means for (I) positioning a sample-containing cuvette and for (II) allowing the filtered beam incident on the cuvette to be transmitted through the cuvette and sample, and for (III) receiving a portion of the filtered beam transmitted through the sample at two or more predetermined angles with respect to the beam; and (5) means for detecting and measuring the portion of the beam transmitted at a predetermined angle

Simple modification of karl-Fischer titration method for determination of water content in colored samples.

Science.gov (United States)

Tavčar, Eva; Turk, Erika; Kreft, Samo

2012-01-01

The most commonly used technique for water content determination is Karl-Fischer titration with electrometric detection, requiring specialized equipment. When appropriate equipment is not available, the method can be performed through visual detection of a titration endpoint, which does not enable an analysis of colored samples. Here, we developed a method with spectrophotometric detection of a titration endpoint, appropriate for moisture determination of colored samples. The reaction takes place in a sealed 4 ml cuvette. Detection is performed at 520 nm. Titration endpoint is determined from the graph of absorbance plotted against titration volume. The method has appropriate reproducibility (RSD = 4.3%), accuracy, and linearity (R(2) = 0.997).

Sample handling in surface sensitive chemical and biological sensing: a practical review of basic fluidics and analyte transport.

Science.gov (United States)

Orgovan, Norbert; Patko, Daniel; Hos, Csaba; Kurunczi, Sándor; Szabó, Bálint; Ramsden, Jeremy J; Horvath, Robert

2014-09-01

This paper gives an overview of the advantages and associated caveats of the most common sample handling methods in surface-sensitive chemical and biological sensing. We summarize the basic theoretical and practical considerations one faces when designing and assembling the fluidic part of the sensor devices. The influence of analyte size, the use of closed and flow-through cuvettes, the importance of flow rate, tubing length and diameter, bubble traps, pressure-driven pumping, cuvette dead volumes, and sample injection systems are all discussed. Typical application areas of particular arrangements are also highlighted, such as the monitoring of cellular adhesion, biomolecule adsorption-desorption and ligand-receptor affinity binding. Our work is a practical review in the sense that for every sample handling arrangement considered we present our own experimental data and critically review our experience with the given arrangement. In the experimental part we focus on sample handling in optical waveguide lightmode spectroscopy (OWLS) measurements, but the present study is equally applicable for other biosensing technologies in which an analyte in solution is captured at a surface and its presence is monitored. Explicit attention is given to features that are expected to play an increasingly decisive role in determining the reliability of (bio)chemical sensing measurements, such as analyte transport to the sensor surface; the distorting influence of dead volumes in the fluidic system; and the appropriate sample handling of cell suspensions (e.g. their quasi-simultaneous deposition). At the appropriate places, biological aspects closely related to fluidics (e.g. cellular mechanotransduction, competitive adsorption, blood flow in veins) are also discussed, particularly with regard to their models used in biosensing. Copyright © 2014 Elsevier B.V. All rights reserved.

Foundations and latest advances in replica exchange transition interface sampling

Science.gov (United States)

Cabriolu, Raffaela; Skjelbred Refsnes, Kristin M.; Bolhuis, Peter G.; van Erp, Titus S.

2017-10-01

Nearly 20 years ago, transition path sampling (TPS) emerged as an alternative method to free energy based approaches for the study of rare events such as nucleation, protein folding, chemical reactions, and phase transitions. TPS effectively performs Monte Carlo simulations with relatively short molecular dynamics trajectories, with the advantage of not having to alter the actual potential energy surface nor the underlying physical dynamics. Although the TPS approach also introduced a methodology to compute reaction rates, this approach was for a long time considered theoretically attractive, providing the exact same results as extensively long molecular dynamics simulations, but still expensive for most relevant applications. With the increase of computer power and improvements in the algorithmic methodology, quantitative path sampling is finding applications in more and more areas of research. In particular, the transition interface sampling (TIS) and the replica exchange TIS (RETIS) algorithms have, in turn, improved the efficiency of quantitative path sampling significantly, while maintaining the exact nature of the approach. Also, open-source software packages are making these methods, for which implementation is not straightforward, now available for a wider group of users. In addition, a blooming development takes place regarding both applications and algorithmic refinements. Therefore, it is timely to explore the wide panorama of the new developments in this field. This is the aim of this article, which focuses on the most efficient exact path sampling approach, RETIS, as well as its recent applications, extensions, and variations.

Whole blood analysis rotor assembly having removable cellular sedimentation bowl

Science.gov (United States)

Burtis, C.A.; Johnson, W.F.

1975-08-26

A rotor assembly for performing photometric analyses using whole blood samples is described. Following static loading of a gross blood sample within a centrally located, removable, cell sedimentation bowl, the red blood cells in the gross sample are centrifugally separated from the plasma, the plasm displaced from the sedimentation bowl, and measured subvolumes of plasma distributed to respective sample analysis cuvettes positioned in an annular array about the rotor periphery. Means for adding reagents to the respective cuvettes are also described. (auth)

Efficient Round-Trip Time Optimization for Replica-Exchange Enveloping Distribution Sampling (RE-EDS).

Science.gov (United States)

Sidler, Dominik; Cristòfol-Clough, Michael; Riniker, Sereina

2017-06-13

Replica-exchange enveloping distribution sampling (RE-EDS) allows the efficient estimation of free-energy differences between multiple end-states from a single molecular dynamics (MD) simulation. In EDS, a reference state is sampled, which can be tuned by two types of parameters, i.e., smoothness parameters(s) and energy offsets, such that all end-states are sufficiently sampled. However, the choice of these parameters is not trivial. Replica exchange (RE) or parallel tempering is a widely applied technique to enhance sampling. By combining EDS with the RE technique, the parameter choice problem could be simplified and the challenge shifted toward an optimal distribution of the replicas in the smoothness-parameter space. The choice of a certain replica distribution can alter the sampling efficiency significantly. In this work, global round-trip time optimization (GRTO) algorithms are tested for the use in RE-EDS simulations. In addition, a local round-trip time optimization (LRTO) algorithm is proposed for systems with slowly adapting environments, where a reliable estimate for the round-trip time is challenging to obtain. The optimization algorithms were applied to RE-EDS simulations of a system of nine small-molecule inhibitors of phenylethanolamine N-methyltransferase (PNMT). The energy offsets were determined using our recently proposed parallel energy-offset (PEOE) estimation scheme. While the multistate GRTO algorithm yielded the best replica distribution for the ligands in water, the multistate LRTO algorithm was found to be the method of choice for the ligands in complex with PNMT. With this, the 36 alchemical free-energy differences between the nine ligands were calculated successfully from a single RE-EDS simulation 10 ns in length. Thus, RE-EDS presents an efficient method for the estimation of relative binding free energies.

Carbon dioxide exchange in Norway spruce at the shoot, tree and ecosystem scale.

Science.gov (United States)

Wallin, G; Linder, S; Lindroth, A; Räntfors, M; Flemberg, S; Grelle, A

2001-08-01

Net CO2 exchange in a 35-year-old boreal Norway spruce (Picea abies (L.) Karst.) forest in northern Sweden was measured at the shoot (NSE), tree (NTE) and ecosystem levels (NEE) by means of shoot cuvettes, whole-tree chambers and the eddy covariance technique, respectively. We compared the dynamics of gross primary production (GPP) at the three levels during the course of a single week. The diurnal dynamics of GPP at each level were estimated by subtracting half-hourly or hourly model-estimated values of total respiration (excluding light-dependent respiration) from net CO(2) exchange. The relationship between temperature and total respiration at each level was derived from nighttime measurements of NSE, NTE and NEE over the course of 1 month. There was a strong linear relationship (r2 = 0.93) between the hourly estimates of GPP at the shoot and tree levels, but the correlation between shoot- and ecosystem-level GPP was weaker (r2 = 0.69). However, the correlation between shoot- and ecosystem-level GPP was improved (r2 = 0.88) if eddy covariance measurements were restricted to periods when friction velocity was > or = 0.5 m s(-1). Daily means were less dependent on friction velocity, giving an r2 value of 0.94 between shoot- and ecosystem-level GPP. The correlation between shoot and tree levels also increased when daily means were compared (r2 = 0.98). Most of the measured variation in carbon exchange rate among the shoot, tree and ecosystem levels was the result of periodic low coupling between vegetation and the atmosphere at the ecosystem level. The results validate the use of measurements at the shoot and tree level for analyzing the contribution of different compartments to net ecosystem CO2 exchange.

Simple Modification of Karl-Fischer Titration Method for Determination of Water Content in Colored Samples

Science.gov (United States)

Tavčar, Eva; Turk, Erika; Kreft, Samo

2012-01-01

The most commonly used technique for water content determination is Karl-Fischer titration with electrometric detection, requiring specialized equipment. When appropriate equipment is not available, the method can be performed through visual detection of a titration endpoint, which does not enable an analysis of colored samples. Here, we developed a method with spectrophotometric detection of a titration endpoint, appropriate for moisture determination of colored samples. The reaction takes place in a sealed 4 ml cuvette. Detection is performed at 520 nm. Titration endpoint is determined from the graph of absorbance plotted against titration volume. The method has appropriate reproducibility (RSD = 4.3%), accuracy, and linearity (R 2 = 0.997). PMID:22567558

Simple Modification of Karl-Fischer Titration Method for Determination of Water Content in Colored Samples

Directory of Open Access Journals (Sweden)

Eva Tavčar

2012-01-01

Full Text Available The most commonly used technique for water content determination is Karl-Fischer titration with electrometric detection, requiring specialized equipment. When appropriate equipment is not available, the method can be performed through visual detection of a titration endpoint, which does not enable an analysis of colored samples. Here, we developed a method with spectrophotometric detection of a titration endpoint, appropriate for moisture determination of colored samples. The reaction takes place in a sealed 4 ml cuvette. Detection is performed at 520 nm. Titration endpoint is determined from the graph of absorbance plotted against titration volume. The method has appropriate reproducibility (RSD=4.3%, accuracy, and linearity (2=0.997.

Determination of γ-hydroxybutyrate in human urine samples by ion exclusion and ion exchange two-dimensional chromatography system.

Science.gov (United States)

Liu, Junwei; Deng, Zhifen; Zhu, Zuoyi; Wang, Yong; Wang, Guoqing; Sun, Yu-An; Zhu, Yan

2017-12-15

A two-dimensional ion chromatography system was developed for the determination of γ-hydroxybutyrate (GHB) in human urine samples. Ion exclusion chromatography was used in the first dimensional separation for elimination of urine matrices and detection of GHB above 10mgL -1 , ion exchange chromatography was used in the second dimensional separation via column-switching technique for detection of GHB above 0.08mgL -1 . Under the optimized chromatographic conditions, the ion exclusion and ion exchange chromatography separation system exhibited satisfactory repeatability (RSDchromatography system was convenient and practical for the determination of GHB in human urine samples. Copyright © 2017 Elsevier B.V. All rights reserved.

Using the multi-objective optimization replica exchange Monte Carlo enhanced sampling method for protein-small molecule docking.

Science.gov (United States)

Wang, Hongrui; Liu, Hongwei; Cai, Leixin; Wang, Caixia; Lv, Qiang

2017-07-10

In this study, we extended the replica exchange Monte Carlo (REMC) sampling method to protein-small molecule docking conformational prediction using RosettaLigand. In contrast to the traditional Monte Carlo (MC) and REMC sampling methods, these methods use multi-objective optimization Pareto front information to facilitate the selection of replicas for exchange. The Pareto front information generated to select lower energy conformations as representative conformation structure replicas can facilitate the convergence of the available conformational space, including available near-native structures. Furthermore, our approach directly provides min-min scenario Pareto optimal solutions, as well as a hybrid of the min-min and max-min scenario Pareto optimal solutions with lower energy conformations for use as structure templates in the REMC sampling method. These methods were validated based on a thorough analysis of a benchmark data set containing 16 benchmark test cases. An in-depth comparison between MC, REMC, multi-objective optimization-REMC (MO-REMC), and hybrid MO-REMC (HMO-REMC) sampling methods was performed to illustrate the differences between the four conformational search strategies. Our findings demonstrate that the MO-REMC and HMO-REMC conformational sampling methods are powerful approaches for obtaining protein-small molecule docking conformational predictions based on the binding energy of complexes in RosettaLigand.

Minimizing Back Exchange in the Hydrogen Exchange-Mass Spectrometry Experiment

Science.gov (United States)

Walters, Benjamin T.; Ricciuti, Alec; Mayne, Leland; Englander, S. Walter

2012-12-01

The addition of mass spectrometry (MS) analysis to the hydrogen exchange (HX) proteolytic fragmentation experiment extends powerful HX methodology to the study of large biologically important proteins. A persistent problem is the degradation of HX information due to back exchange of deuterium label during the fragmentation-separation process needed to prepare samples for MS measurement. This paper reports a systematic analysis of the factors that influence back exchange (solution pH, ionic strength, desolvation temperature, LC column interaction, flow rates, system volume). The many peptides exhibit a range of back exchange due to intrinsic amino acid HX rate differences. Accordingly, large back exchange leads to large variability in D-recovery from one residue to another as well as one peptide to another that cannot be corrected for by reference to any single peptide-level measurement. The usual effort to limit back exchange by limiting LC time provides little gain. Shortening the LC elution gradient by 3-fold only reduced back exchange by ~2 %, while sacrificing S/N and peptide count. An unexpected dependence of back exchange on ionic strength as well as pH suggests a strategy in which solution conditions are changed during sample preparation. Higher salt should be used in the first stage of sample preparation (proteolysis and trapping) and lower salt (<20 mM) and pH in the second stage before electrospray injection. Adjustment of these and other factors together with recent advances in peptide fragment detection yields hundreds of peptide fragments with D-label recovery of 90 % ± 5 %.

Minimizing back exchange in the hydrogen exchange-mass spectrometry experiment.

Science.gov (United States)

Walters, Benjamin T; Ricciuti, Alec; Mayne, Leland; Englander, S Walter

2012-12-01

The addition of mass spectrometry (MS) analysis to the hydrogen exchange (HX) proteolytic fragmentation experiment extends powerful HX methodology to the study of large biologically important proteins. A persistent problem is the degradation of HX information due to back exchange of deuterium label during the fragmentation-separation process needed to prepare samples for MS measurement. This paper reports a systematic analysis of the factors that influence back exchange (solution pH, ionic strength, desolvation temperature, LC column interaction, flow rates, system volume). The many peptides exhibit a range of back exchange due to intrinsic amino acid HX rate differences. Accordingly, large back exchange leads to large variability in D-recovery from one residue to another as well as one peptide to another that cannot be corrected for by reference to any single peptide-level measurement. The usual effort to limit back exchange by limiting LC time provides little gain. Shortening the LC elution gradient by 3-fold only reduced back exchange by ~2%, while sacrificing S/N and peptide count. An unexpected dependence of back exchange on ionic strength as well as pH suggests a strategy in which solution conditions are changed during sample preparation. Higher salt should be used in the first stage of sample preparation (proteolysis and trapping) and lower salt (<20 mM) and pH in the second stage before electrospray injection. Adjustment of these and other factors together with recent advances in peptide fragment detection yields hundreds of peptide fragments with D-label recovery of 90% ± 5%.

Efficacy of independence sampling in replica exchange simulations of ordered and disordered proteins.

Science.gov (United States)

Lee, Kuo Hao; Chen, Jianhan

2017-11-15

Recasting temperature replica exchange (T-RE) as a special case of Gibbs sampling has led to a simple and efficient scheme for enhanced mixing (Chodera and Shirts, J. Chem. Phys., 2011, 135, 194110). To critically examine if T-RE with independence sampling (T-REis) improves conformational sampling, we performed T-RE and T-REis simulations of ordered and disordered proteins using coarse-grained and atomistic models. The results demonstrate that T-REis effectively increase the replica mobility in temperatures space with minimal computational overhead, especially for folded proteins. However, enhanced mixing does not translate well into improved conformational sampling. The convergences of thermodynamic properties interested are similar, with slight improvements for T-REis of ordered systems. The study re-affirms the efficiency of T-RE does not appear to be limited by temperature diffusion, but by the inherent rates of spontaneous large-scale conformational re-arrangements. Due to its simplicity and efficacy of enhanced mixing, T-REis is expected to be more effective when incorporated with various Hamiltonian-RE protocols. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Method and apparatus for automated processing and aliquoting of whole blood samples for analysis in a centrifugal fast analyzer

Science.gov (United States)

Burtis, C.A.; Johnson, W.F.; Walker, W.A.

1985-08-05

A rotor and disc assembly for use in a centrifugal fast analyzer. The assembly is designed to process multiple samples of whole blood followed by aliquoting of the resultant serum into precisely measured samples for subsequent chemical analysis. The assembly requires minimal operator involvement with no mechanical pipetting. The system comprises: (1) a whole blood sample disc; (2) a serum sample disc; (3) a sample preparation rotor; and (4) an analytical rotor. The blood sample disc and serum sample disc are designed with a plurality of precision bore capillary tubes arranged in a spoked array. Samples of blood are loaded into the blood sample disc by capillary action and centrifugally discharged into cavities of the sample preparation rotor where separation of serum and solids is accomplished. The serum is loaded into the capillaries of the serum sample disc by capillary action and subsequently centrifugally expelled into cuvettes of the analyticaly rotor for conventional methods. 5 figs.

Method and apparatus for automated processing and aliquoting of whole blood samples for analysis in a centrifugal fast analyzer

Science.gov (United States)

Burtis, Carl A.; Johnson, Wayne F.; Walker, William A.

1988-01-01

A rotor and disc assembly for use in a centrifugal fast analyzer. The assembly is designed to process multiple samples of whole blood followed by aliquoting of the resultant serum into precisely measured samples for subsequent chemical analysis. The assembly requires minimal operator involvement with no mechanical pipetting. The system comprises (1) a whole blood sample disc, (2) a serum sample disc, (3) a sample preparation rotor, and (4) an analytical rotor. The blood sample disc and serum sample disc are designed with a plurality of precision bore capillary tubes arranged in a spoked array. Samples of blood are loaded into the blood sample disc in capillary tubes filled by capillary action and centrifugally discharged into cavities of the sample preparation rotor where separation of serum and solids is accomplished. The serum is loaded into the capillaries of the serum sample disc by capillary action and subsequently centrifugally expelled into cuvettes of the analytical rotor for analysis by conventional methods.

AMORE-HX: a multidimensional optimization of radial enhanced NMR-sampled hydrogen exchange

International Nuclear Information System (INIS)

Gledhill, John M.; Walters, Benjamin T.; Wand, A. Joshua

2009-01-01

The Cartesian sampled three-dimensional HNCO experiment is inherently limited in time resolution and sensitivity for the real time measurement of protein hydrogen exchange. This is largely overcome by use of the radial HNCO experiment that employs the use of optimized sampling angles. The significant practical limitation presented by use of three-dimensional data is the large data storage and processing requirements necessary and is largely overcome by taking advantage of the inherent capabilities of the 2D-FT to process selective frequency space without artifact or limitation. Decomposition of angle spectra into positive and negative ridge components provides increased resolution and allows statistical averaging of intensity and therefore increased precision. Strategies for averaging ridge cross sections within and between angle spectra are developed to allow further statistical approaches for increasing the precision of measured hydrogen occupancy. Intensity artifacts potentially introduced by over-pulsing are effectively eliminated by use of the BEST approach

The determination of radioactive strontium in environmental samples by preferential ion exchange separation from calcium

International Nuclear Information System (INIS)

Fukushima, Hiroto; Nonaka, Nobuhiro; Honda, Tetsutaro; Kimura, Toshimasa; Higuchi, Hideo

1979-01-01

The determination of radioactive strontium in environmental samples involves a difficulty in the separation and purification of strontium from large amounts of calcium. The principal technique employed in this study is based on a cation exchange separation after preferential chelation of calcium over strontium by EDTA. The alkaline earth fraction separated from samples is dissolved in 1.2 M HCl and an equivalent amount of EDTA is added. The solution is passed through a Dowex 50W-X8 ion exchange column at a flow rate of 20 ml/min after the pH has been adjusted to 5.1. A fraction of calcium retained on the resin is eluted out with 1.8 l of 2 w/v% EDTA solution at pH 5.1. Then the strontium is eluted with 450 ml of 2 M HCl. The strontium carbonate is precipitated, and the chemical yield is determined. After standing for 14 days to reach the radioactive equilibrium of 90 Sr - 90 Y, the activity of 89 Sr + 90 Sr + 90 Y is measured. Then the activity of 90 Sr + 90 Y is measured by milking the 90 Y. The proposed procedure has been applied to sea water, soil and various ash samples of vegetables, seaweeds and daily foods. The results obtained are in good agreement with those by a classical fuming nitric acid precipitation method. The detection limits are 0.1 pCi/l for 10 l of sea water, 10 pCi/kg for 100 g of soil and 1 pCi/kg-fresh for 20 g ash samples, respectively. (author)

Sample Handling and Chemical Kinetics in an Acoustically Levitated Drop Microreactor

Science.gov (United States)

2009-01-01

Accurate measurement of enzyme kinetics is an essential part of understanding the mechanisms of biochemical reactions. The typical means of studying such systems use stirred cuvettes, stopped-flow apparatus, microfluidic systems, or other small sample containers. These methods may prove to be problematic if reactants or products adsorb to or react with the container’s surface. As an alternative approach, we have developed an acoustically-levitated drop reactor eventually intended to study enzyme-catalyzed reaction kinetics related to free radical and oxidative stress chemistry. Microliter-scale droplet generation, reactant introduction, maintenance, and fluid removal are all important aspects in conducting reactions in a levitated drop. A three capillary bundle system has been developed to address these needs. We report kinetic measurements for both luminol chemiluminescence and the reaction of pyruvate with nicotinamide adenine dinucleotide, catalyzed by lactate dehydrogenase, to demonstrate the feasibility of using a levitated drop in conjunction with the developed capillary sample handling system as a microreactor. PMID:19769373

The use of lichens in post-smelting dumps reclamation - preliminary results of experimental cultivation of selected species on slag substrate

Science.gov (United States)

Rola, Kaja; Osyczka, Piotr

2017-11-01

Conventional reclamation interventions of post-smelting slag dumps being undertaken so far either failed or produced poor results. Certain lichens, especially of the genus Cladonia, are known as effective colonisers of bare ground in anthropogenic habitats. The paper presents preliminary results of the experiment aimed at the evaluation of lichen usefulness in reclamation interventions. The cultivation in vivo involving transplantation of lichens directly on slag substrate was established in 2015. Five species, i.e. Cladonia rei, C. cariosa, C. pyxidata, C. subulata, C. macilenta, were transplanted into 32 cuvettes filled with sterilised slag substrate. The sample weight of 2 and 6 g were used and half of cuvettes were regularly supplied with 2% malt solution. The first important symptoms at the present stage of the experiment are as follow: the growth of thalli has appeared only in the case of first three species; C. rei shows the most effective development; cuvettes with 6 g sample weight are characterized by higher coverage of fresh lichen thalli; lichen biomass are visually higher in cuvettes treated with malt solution. The results give us reason to believe that lichens could be successfully used as an alternative element during planning of slag dumps reclamation in the future.

The use of lichens in post-smelting dumps reclamation – preliminary results of experimental cultivation of selected species on slag substrate

Directory of Open Access Journals (Sweden)

Rola Kaja

2017-01-01

Full Text Available Conventional reclamation interventions of post-smelting slag dumps being undertaken so far either failed or produced poor results. Certain lichens, especially of the genus Cladonia, are known as effective colonisers of bare ground in anthropogenic habitats. The paper presents preliminary results of the experiment aimed at the evaluation of lichen usefulness in reclamation interventions. The cultivation in vivo involving transplantation of lichens directly on slag substrate was established in 2015. Five species, i.e. Cladonia rei, C. cariosa, C. pyxidata, C. subulata, C. macilenta, were transplanted into 32 cuvettes filled with sterilised slag substrate. The sample weight of 2 and 6 g were used and half of cuvettes were regularly supplied with 2% malt solution. The first important symptoms at the present stage of the experiment are as follow: the growth of thalli has appeared only in the case of first three species; C. rei shows the most effective development; cuvettes with 6 g sample weight are characterized by higher coverage of fresh lichen thalli; lichen biomass are visually higher in cuvettes treated with malt solution. The results give us reason to believe that lichens could be successfully used as an alternative element during planning of slag dumps reclamation in the future.

Monte Carlo Simulation Of The Portfolio-Balance Model Of Exchange Rates: Finite Sample Properties Of The GMM Estimator

OpenAIRE

Hong-Ghi Min

2011-01-01

Using Monte Carlo simulation of the Portfolio-balance model of the exchange rates, we report finite sample properties of the GMM estimator for testing over-identifying restrictions in the simultaneous equations model. F-form of Sargans statistic performs better than its chi-squared form while Hansens GMM statistic has the smallest bias.

Chemical exchange rotation transfer imaging of intermediate-exchanging amines at 2 ppm.

Science.gov (United States)

Zu, Zhongliang; Louie, Elizabeth A; Lin, Eugene C; Jiang, Xiaoyu; Does, Mark D; Gore, John C; Gochberg, Daniel F

2017-10-01

Chemical exchange saturation transfer (CEST) imaging of amine protons exchanging at intermediate rates and whose chemical shift is around 2 ppm may provide a means of mapping creatine. However, the quantification of this effect may be compromised by the influence of overlapping CEST signals from fast-exchanging amines and hydroxyls. We aimed to investigate the exchange rate filtering effect of a variation of CEST, named chemical exchange rotation transfer (CERT), as a means of isolating creatine contributions at around 2 ppm from other overlapping signals. Simulations were performed to study the filtering effects of CERT for the selection of transfer effects from protons of specific exchange rates. Control samples containing the main metabolites in brain, bovine serum albumin (BSA) and egg white albumen (EWA) at their physiological concentrations and pH were used to study the ability of CERT to isolate molecules with amines at 2 ppm that exchange at intermediate rates, and corresponding methods were used for in vivo rat brain imaging. Simulations showed that exchange rate filtering can be combined with conventional filtering based on chemical shift. Studies on samples showed that signal contributions from creatine can be separated from those of other metabolites using this combined filter, but contributions from protein amines may still be significant. This exchange filtering can also be used for in vivo imaging. CERT provides more specific quantification of amines at 2 ppm that exchange at intermediate rates compared with conventional CEST imaging. Copyright © 2017 John Wiley & Sons, Ltd.

Operation of the pneumatic exchanger of samples during the realization of TARC experiments at CERN

International Nuclear Information System (INIS)

Cerro, E.; Gonzalez, O.; Bueno, J.; Aleixadre, J.; Tamarit, J.

1997-01-01

The CEDEX has designed and developed a pneumatic exchanger of samples (''Rabbit??) that has permitted to make several tests to validate the theoretical studies of the energy amplifier at CERN, under the program ''Nuclear Fission Safety'' of the Europe Union. In a previous article published in this review, issue 103/1996, it was described the design and development of the system. In this, it has described its location in the experimental area at CERN (Geneva), and the results of the performance during the main fast extraction week, the Rabbit was used full time. (Author)

Biogenic Volatile Organic Compound (BVOC) emissions from agricultural crop species: is guttation a possible source for methanol emissions following light/dark transition ?

Science.gov (United States)

Mozaffar, Ahsan; Amelynck, Crist; Bachy, Aurélie; Digrado, Anthony; Delaplace, Pierre; du Jardin, Patrick; Fauconnier, Marie-Laure; Schoon, Niels; Aubinet, Marc; Heinesch, Bernard

2015-04-01

In the framework of the CROSTVOC (CROp STress VOC) project, the exchange of biogenic volatile organic compounds (BVOCs) between two important agricultural crop species, maize and winter wheat, and the atmosphere has recently been measured during an entire growing season by using the eddy covariance technique. Because of the co-variation of BVOC emission drivers in field conditions, laboratory studies were initiated in an environmental chamber in order to disentangle the responses of the emissions to variations of the individual environmental parameters (such as PPFD and temperature) and to diverse abiotic stress factors. Young plants were enclosed in transparent all-Teflon dynamic enclosures (cuvettes) through which BVOC-free and RH-controlled air was sent. BVOC enriched air was subsequently sampled from the plant cuvettes and an empty cuvette (background) and analyzed for BVOCs in a high sensitivity Proton Transfer Reaction Mass Spectrometer (hs-PTR-MS) and for CO2 in a LI-7000 non-dispersive IR gas analyzer. Emissions were monitored at constant temperature (25 °C) and at a stepwise varying PPFD pattern (0-650 µmol m-2 s-1). For maize plants, sudden light/dark transitions at the end of the photoperiod were accompanied by prompt and considerable increases in methanol (m/z 33) and water vapor (m/z 39) emissions. Moreover, guttation droplets appeared on the sides and the tips of the leaves within a few minutes after light/dark transition. Therefore the assumption has been raised that methanol is also coming out with guttation fluid from the leaves. Consequently, guttation fluid was collected from young maize and wheat plants, injected in an empty enclosure and sampled by PTR-MS. Methanol and a large number of other compounds were observed from guttation fluid. Recent studies have shown that guttation from agricultural crops frequently occurs in field conditions. Further research is required to find out the source strength of methanol emissions by this guttation

Multistage Magnetic Separator of Cells and Proteins

Science.gov (United States)

Barton, Ken; Ainsworth, Mark; Daily, Bruce; Dunn, Scott; Metz, Bill; Vellinger, John; Taylor, Brock; Meador, Bruce

2005-01-01

The multistage electromagnetic separator for purifying cells and magnetic particles (MAGSEP) is a laboratory apparatus for separating and/or purifying particles (especially biological cells) on the basis of their magnetic susceptibility and magnetophoretic mobility. Whereas a typical prior apparatus based on similar principles offers only a single stage of separation, the MAGSEP, as its full name indicates, offers multiple stages of separation; this makes it possible to refine a sample population of particles to a higher level of purity or to categorize multiple portions of the sample on the basis of magnetic susceptibility and/or magnetophoretic mobility. The MAGSEP includes a processing unit and an electronic unit coupled to a personal computer. The processing unit includes upper and lower plates, a plate-rotation system, an electromagnet, an electromagnet-translation system, and a capture-magnet assembly. The plates are bolted together through a roller bearing that allows the plates to rotate with respect to each other. An interface between the plates acts as a seal for separating fluids. A lower cuvette can be aligned with as many as 15 upper cuvette stations for fraction collection during processing. A two-phase stepping motor drives the rotation system, causing the upper plate to rotate for the collection of each fraction of the sample material. The electromagnet generates a magnetic field across the lower cuvette, while the translation system translates the electromagnet upward along the lower cuvette. The current supplied to the electromagnet, and thus the magnetic flux density at the pole face of the electromagnet, can be set at a programmed value between 0 and 1,400 gauss (0.14 T). The rate of translation can be programmed between 5 and 2,000 m/s so as to align all sample particles in the same position in the cuvette. The capture magnet can be a permanent magnet. It is mounted on an arm connected to a stepping motor. The stepping motor rotates the arm to

Study of kinetics, equilibrium and isotope exchange in ion exchange systems Pt. 4

International Nuclear Information System (INIS)

Stamberg, K.; Plicka, J.; Calibar, J.; Gosman, A.

1985-01-01

The kinetics of ion exchange in the Nasup(+)-Mgsup(2+)-strongly acidic cation exchanger system in a batch stirred reactor was studied. The samples of exchangers OSTION KS (containing DVB in the range of 1.5 - 12%) and AMBERLITE IR 120 for experimental work were used; the concentration of the aqueous nitrate solution was always 0.2M. The Nernst-Planck equation for description of diffusion of ions in a particle was used. The values of diffusion coefficients of magnesium ions in the exchangers and their dependence on the content of DVB were obtained by evaluating the experimental data and using the self-diffusion coefficients of sodium. (author)

Current status and future prospects of an automated sample exchange system PAM for protein crystallography

Science.gov (United States)

Hiraki, M.; Yamada, Y.; Chavas, L. M. G.; Matsugaki, N.; Igarashi, N.; Wakatsuki, S.

2013-03-01

To achieve fully-automated and/or remote data collection in high-throughput X-ray experiments, the Structural Biology Research Centre at the Photon Factory (PF) has installed PF automated mounting system (PAM) for sample exchange robots at PF macromolecular crystallography beamlines BL-1A, BL-5A, BL-17A, AR-NW12A and AR-NE3A. We are upgrading the experimental systems, including the PAM for stable and efficient operation. To prevent human error in automated data collection, we installed a two-dimensional barcode reader for identification of the cassettes and sample pins. Because no liquid nitrogen pipeline in the PF experimental hutch is installed, the users commonly add liquid nitrogen using a small Dewar. To address this issue, an automated liquid nitrogen filling system that links a 100-liter tank to the robot Dewar has been installed on the PF macromolecular beamline. Here we describe this new implementation, as well as future prospects.

Oxygen isotope exchange on palladium catalysts

International Nuclear Information System (INIS)

Kravchuk, L.S.; Beschetvertnaya, T.I.; Novorodskij, V.G.; Novikova, M.G.; Zaretskij, M.V.; Valieva, S.V.

1983-01-01

Oxygen heteromolecular isotope exchange on unreduced palladium catalysts, distingushing by metal content is studied. Content of 18 O in gaseous phase is eoual to 46%. Calculations of heteroexchange rates are conducted with decrease of the 18 O in the gaseous phase over solid sample. Method of oxygen thermodesorption has been used to establish that palladium, deposited on γ-Al 2 O 3 during exchange process is in oxidized state; in this case strength of Pd-O bond is determined by content dispersity) of the metal. It is shown that significant increase of exchange rate on the samples with Pd >> 0.5 mass.% content can be induced as by side decomposition reaction of its oxide and corresponding dilution of gaseous mixture by ''light'' oxygen so by possibility of exchange with oxygen of PdO phase

Assessment of contemporary genetic diversity and inter-taxa/inter-region exchange of avian paramyxovirus serotype 1 in wild birds sampled in North America

Science.gov (United States)

Ramey, Andy M.; Goraichuk, Iryna V.; Hicks, Joseph T.; Dimitrov, Kiril M.; Poulson, Rebecca L.; Stallknecht, David E.; Bahl, Justin; Afonso, Claudio L.

2017-01-01

BackgroundAvian paramyxovirus serotype 1 (APMV-1) viruses are globally distributed, infect wild, peridomestic, and domestic birds, and sometimes lead to outbreaks of disease. Thus, the maintenance, evolution, and spread of APMV-1 viruses are relevant to avian health.MethodsIn this study we sequenced the fusion gene from 58 APMV-1 isolates recovered from thirteen species of wild birds sampled throughout the USA during 2007–2014. We analyzed sequence information with previously reported data in order to assess contemporary genetic diversity and inter-taxa/inter-region exchange of APMV-1 in wild birds sampled in North America.ResultsOur results suggest that wild birds maintain previously undescribed genetic diversity of APMV-1; however, such diversity is unlikely to be pathogenic to domestic poultry. Phylogenetic analyses revealed that APMV-1 diversity detected in wild birds of North America has been found in birds belonging to numerous taxonomic host orders and within hosts inhabiting multiple geographic regions suggesting some level of viral exchange. However, our results also provide statistical support for associations between phylogenetic tree topology and host taxonomic order/region of sample origin which supports restricted exchange among taxa and geographical regions of North America for some APMV-1 sub-genotypes.ConclusionsWe identify previously unrecognized genetic diversity of APMV-1 in wild birds in North America which is likely a function of continued viral evolution in reservoir hosts. We did not, however, find support for the emergence or maintenance of APMV-1 strains predicted to be pathogenic to poultry in wild birds of North America outside of the order Suliformes (i.e., cormorants). Furthermore, genetic evidence suggests that ecological drivers or other mechanisms may restrict viral exchange among taxa and regions of North America. Additional and more systematic sampling for APMV-1 in North America would likely provide further inference on viral

Heat exchanger restart evaluation

International Nuclear Information System (INIS)

Morrison, J.M.; Hirst, C.W.; Lentz, T.F.

1992-01-01

On December 24, 1991, the K-Reactor was in the shutdown mode with full AC process water flow and full cooling water flow. Safety rod testing was being performed as part of the power ascension testing program. The results of cooling water samples indicated tritium concentrations higher than allowable. Further sampling and testing confirmed a Process Water System to Cooling Water System leak in heat exchanger 4A (HX 4A). The heat exchanger was isolated and the plant shutdown. Heat exchanger 4kA was removed from the plant and moved to C-Area prior to performing examinations and diagnostic testing. This included locating and identifying the leaking tube or tubes, eddy current examination of the leaking tube and a number of adjacent tubes, visually inspecting the leaking tube from both the inside as well as the area surrounding the failure mechanism. In addition ten other tubes that either exhibited eddy current indications or would represent a baseline condition were removed from heat exchanger 4A for metallurgical examination. Additional analysis and review of heat exchanger leakage history was performed to determine if there are any patterns which can be used for predictive purposes. Compensatory actions have been taken to improve the sensitivity and response time to any future events of this type. The results of these actions are summarized herein

Rapid isolation of plutonium in environmental solid samples using sequential injection anion exchange chromatography followed by detection with inductively coupled plasma mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Qiao Jixin, E-mail: jixin.qiao@risoe.d [Radiation Research Division, Riso National Laboratory for Sustainable Energy, Technical University of Denmark, DK-4000 Roskilde (Denmark); Hou Xiaolin; Roos, Per [Radiation Research Division, Riso National Laboratory for Sustainable Energy, Technical University of Denmark, DK-4000 Roskilde (Denmark); Miro, Manuel [Department of Chemistry, Faculty of Sciences, University of the Balearic Islands, Carretera de Valldemossa km. 7.5, E-07122 Palma de Mallorca, Illes Balears (Spain)

2011-01-31

This paper reports an automated analytical method for rapid determination of plutonium isotopes ({sup 239}Pu and {sup 240}Pu) in environmental solid extracts. Anion exchange chromatographic columns were incorporated in a sequential injection (SI) system to undertake the automated separation of plutonium from matrix and interfering elements. The analytical results most distinctly demonstrated that the crosslinkage of the anion exchanger is a key parameter controlling the separation efficiency. AG 1-x4 type resin was selected as the most suitable sorbent material for analyte separation. Investigation of column size effect upon the separation efficiency revealed that small-sized (2 mL) columns sufficed to handle up to 50 g of environmental soil samples. Under the optimum conditions, chemical yields of plutonium exceeded 90% and the decontamination factors for uranium, thorium and lead ranged from 10{sup 3} to 10{sup 4}. The determination of plutonium isotopes in three standard/certified reference materials (IAEA-375 soil, IAEA-135 sediment and NIST-4359 seaweed) and two reference samples (Irish Sea sediment and Danish soil) revealed a good agreement with reference/certified values. The SI column-separation method is straightforward and less labor intensive as compared with batch-wise anion exchange chromatographic procedures. Besides, the automated method features low consumption of ion-exchanger and reagents for column washing and elution, with the consequent decrease in the generation of acidic waste, thus bearing green chemical credentials.

Real exchange rate misalignments

OpenAIRE

Terra, Maria Cristina T.; Valladares, Frederico Estrella Carneiro

2003-01-01

This paper characterizes episodes of real appreciations and depreciations for a sample of 85 countries, approximately from 1960 to 1998. First, the equilibrium real exchange rate series are constructed for each country using Goldfajn and Valdes (1999) methodology (cointegration with fundamentals). Then, departures from equilibrium real exchange rate (misalignments) are obtained, and a Markov Switching Model is used to characterize the misalignments series as stochastic autor...

Determination of uranium isotopes in environmental samples by anion exchange in sulfuric and hydrochloric acid media

International Nuclear Information System (INIS)

Popov, L.

2016-01-01

Method for determination of uranium isotopes in various environmental samples is presented. The major advantages of the method are the low cost of the analysis, high radiochemical yields and good decontamination factors from the matrix elements, natural and man-made radionuclides. The separation and purification of uranium is attained by adsorption with strong base anion exchange resin in sulfuric and hydrochloric acid media. Uranium is electrodeposited on a stainless steel disk and measured by alpha spectrometry. The analytical method has been applied for the determination of concentrations of uranium isotopes in mineral, spring and tap waters from Bulgaria. The analytical quality was checked by analyzing reference materials. - Highlights: • The method allows cost-effective determination of U isotopes. • High amounts of environmental samples can be analyzed. • High chemical yields, energy resolution and decontamination factors were achieved. • Uranium isotope concentrations in mineral waters from Bulgaria are presented.

Composition of atmospheric precipitation. I. Sampling technique. Use of ion exchange resins

Energy Technology Data Exchange (ETDEWEB)

Egner, H; Eriksson, E; Emanuelsson, A

1947-01-01

In order to investigate the composition of atmospheric precipitations in Sweden, a technique using ion exchange resins has been developed. The possibilities of nitrate reduction, and ammonia losses, when the precipitation is collected in zinc gauges is stressed. Glass funnels are used, and they are effectively protected from bird droppings. The ion exchange resins so far available are quite serviceable but show some deficiencies as to stability, and activity in alkaline solutions. New resins, which are not yet available, seem to offer definite advantages.

Microvolume protein concentration determination using the NanoDrop 2000c spectrophotometer.

Science.gov (United States)

Desjardins, Philippe; Hansen, Joel B; Allen, Michael

2009-11-04

Traditional spectrophotometry requires placing samples into cuvettes or capillaries. This is often impractical due to the limited sample volumes often used for protein analysis. The Thermo Scientific NanoDrop 2000c Spectrophotometer solves this issue with an innovative sample retention system that holds microvolume samples between two measurement surfaces using the surface tension properties of liquids, enabling the quantification of samples in volumes as low as 0.5-2 microL. The elimination of cuvettes or capillaries allows real time changes in path length, which reduces the measurement time while greatly increasing the dynamic range of protein concentrations that can be measured. The need for dilutions is also eliminated, and preparations for sample quantification are relatively easy as the measurement surfaces can be simply wiped with laboratory wipe. This video article presents modifications to traditional protein concentration determination methods for quantification of microvolume amounts of protein using A280 absorbance readings or the BCA colorimetric assay.

Selective plane illumination microscopy (SPIM) with time-domain fluorescence lifetime imaging microscopy (FLIM) for volumetric measurement of cleared mouse brain samples

Science.gov (United States)

Funane, Tsukasa; Hou, Steven S.; Zoltowska, Katarzyna Marta; van Veluw, Susanne J.; Berezovska, Oksana; Kumar, Anand T. N.; Bacskai, Brian J.

2018-05-01

We have developed an imaging technique which combines selective plane illumination microscopy with time-domain fluorescence lifetime imaging microscopy (SPIM-FLIM) for three-dimensional volumetric imaging of cleared mouse brains with micro- to mesoscopic resolution. The main features of the microscope include a wavelength-adjustable pulsed laser source (Ti:sapphire) (near-infrared) laser, a BiBO frequency-doubling photonic crystal, a liquid chamber, an electrically focus-tunable lens, a cuvette based sample holder, and an air (dry) objective lens. The performance of the system was evaluated with a lifetime reference dye and micro-bead phantom measurements. Intensity and lifetime maps of three-dimensional human embryonic kidney (HEK) cell culture samples and cleared mouse brain samples expressing green fluorescent protein (GFP) (donor only) and green and red fluorescent protein [positive Förster (fluorescence) resonance energy transfer] were acquired. The results show that the SPIM-FLIM system can be used for sample sizes ranging from single cells to whole mouse organs and can serve as a powerful tool for medical and biological research.

Heat exchanger restart evaluation

International Nuclear Information System (INIS)

Morrison, J.M.; Hirst, C.W.; Lentz, T.F.

1992-01-01

On December 24, 1991, the K-Reactor was in the shutdown mode with full AC process water flow and full cooling water flow. Safety rod testing was being performed as part of the power ascension testing program. The results of cooling water samples indicated tritium concentrations higher than allowable. Further sampling and testing confirmed a Process Water System to Cooling Water System leak in heat exchanger 4A (HX 4A). The heat exchanger was isolated and the plant shutdown. Heat exchanger 4A was removed from the plant and moved to C-Area prior to performing examinations and diagnostic testing. This included locating and identifying the leaking tube or tubes, eddy current examination of the leaking tube and a number of adjacent tubes, visually inspecting the leaking tube from both the inside as well as the area surrounding the identified tube. The leaking tube was removed and examined metallurgically to determine the failure mechanism. In addition ten other tubes that either exhibited eddy current indications or would represent a baseline condition were removed from heat exchanger 4A for metallurgical examination. Additional analysis and review of heat exchanger leakage history was performed to determine if there are any patterns which can be used for predictive purposes. Compensatory actions have been taken to improve the sensitivity and response time to any future events of this type. The results of these actions are summarized

Heat exchanger restart evaluation

International Nuclear Information System (INIS)

Morrison, J.M.; Hirst, C.W.; Lentz, T.F.

1992-01-01

On December 24, 1991, the K-Reactor was in the shutdown mode with full AC process water flow and full cooling water flow. Safety rod testing was being performed as part of the power ascension testing program. The results of cooling water samples indicated tritium concentrations higher than allowable. Further sampling and testing confirmed a Process Water System to Cooling Water System leak in heat exchanger 4A (HX 4A). The heat exchanger was isolated and the plant shutdown. Heat exchanger 4A was removed from the plant and moved to C-Area prior to performing examinations and diagnostic testing. This included locating and identifying the leaking tube or tubes, eddy current examination of the leaking tube and a number of adjacent tubes, visually inspecting the leaking tube from both the inside as well as the area surrounding the identified tube. The leaking tube was removed and examined metallurgically to determine the failure mechanism. In addition ten other tubes that either exhibited eddy current indications or would represent a baseline condition were removed from heat exchanger 4A for metallurgical examination. Additional analysis and review of heat exchanger leakage history was performed to determine if there are any patterns which can be used for predictive purposes. Compensatory actions have been taken to improve the sensitivity and response time to any future events of this type. The results of these actions are summary herein

Gaseous and Freely-Dissolved PCBs in the Lower Great Lakes Based on Passive Sampling: Spatial Trends and Air-Water Exchange.

Science.gov (United States)

Liu, Ying; Wang, Siyao; McDonough, Carrie A; Khairy, Mohammed; Muir, Derek C G; Helm, Paul A; Lohmann, Rainer

2016-05-17

Polyethylene passive sampling was performed to quantify gaseous and freely dissolved polychlorinated biphenyls (PCBs) in the air and water of Lakes Erie and Ontario during 2011-2012. In view of differing physical characteristics and the impacts of historical contamination by PCBs within these lakes, spatial variation of PCB concentrations and air-water exchange across these lakes may be expected. Both lakes displayed statistically similar aqueous and atmospheric PCB concentrations. Total aqueous concentrations of 29 PCBs ranged from 1.5 pg L(-1) in the open lake of Lake Erie (site E02) in 2011 spring to 105 pg L(-1) in Niagara (site On05) in 2012 summer, while total atmospheric concentrations were 7.7-634 pg m(-3) across both lakes. A west-to-east gradient was observed for aqueous PCBs in Lake Erie. River discharge and localized influences (e.g., sediment resuspension and regional alongshore transport) likely dominated spatial trends of aqueous PCBs in both lakes. Air-water exchange fluxes of Σ7PCBs ranged from -2.4 (±1.9) ng m(-2) day(-1) (deposition) in Sheffield (site E03) to 9.0 (±3.1) ng m(-2) day(-1) (volatilization) in Niagara (site On05). Net volatilization of PCBs was the primary trend across most sites and periods. Almost half of variation in air-water exchange fluxes was attributed to the difference in aqueous concentrations of PCBs. Uncertainty analysis in fugacity ratios and mass fluxes in air-water exchange of PCBs indicated that PCBs have reached or approached equilibrium only at the eastern Lake Erie and along the Canadian shore of Lake Ontario sites, where air-water exchange fluxes dominated atmospheric concentrations.

Model Uncertainty and Exchange Rate Forecasting

NARCIS (Netherlands)

Kouwenberg, R.; Markiewicz, A.; Verhoeks, R.; Zwinkels, R.C.J.

2017-01-01

Exchange rate models with uncertain and incomplete information predict that investors focus on a small set of fundamentals that changes frequently over time. We design a model selection rule that captures the current set of fundamentals that best predicts the exchange rate. Out-of-sample tests show

The dry heat exchanger calorimeter system

International Nuclear Information System (INIS)

Renz, D.P.; Wetzel, J.R.; James, S.J.; Kasperski, P.W.; Duff, M.F.

1991-01-01

A radiometric isothermal heat flow calorimeter and preconditioner system that uses air instead of water as the heat exchange medium has been developed at Mound. The dry heat exchanger calorimeter is 42 inches high by 18 inches in diameter and the preconditioner is a 22 inch cube, making it extremely compact compared to existing units. The new system is ideally suited for transportable, stand-alone, or glovebox applications. Preliminary tests of the system have produced sample measurements with standard deviations less than 0.25% and sample errors less than 0.50%. These tests have shown that the dry heat exchanger system will yield acceptance data with an accuracy comparable to those of Mound water bath systems now in use. 4 figs., 1 tab

Physician capability to electronically exchange clinical information, 2011.

Science.gov (United States)

Patel, Vaishali; Swain, Matthew J; King, Jennifer; Furukawa, Michael F

2013-10-01

To provide national estimates of physician capability to electronically share clinical information with other providers and to describe variation in exchange capability across states and electronic health record (EHR) vendors using the 2011 National Ambulatory Medical Care Survey Electronic Medical Record Supplement. Survey of a nationally representative sample of nonfederal office-based physicians who provide direct patient care. The survey was administered by mail with telephone follow-up and had a 61% weighted response rate. The overall sample consisted of 4326 respondents. We calculated estimates of electronic exchange capability at the national and state levels, and applied multivariate analyses to examine the association between the capability to exchange different types of clinical information and physician and practice characteristics. In 2011, 55% of physicians had computerized capability to send prescriptions electronically; 67% had the capability to view lab results electronically; 42% were able to incorporate lab results into their EHR; 35% were able to send lab orders electronically; and, 31% exchanged patient clinical summaries with other providers. The strongest predictor of exchange capability is adoption of an EHR. However, substantial variation exists across geography and EHR vendors in exchange capability, especially electronic exchange of clinical summaries. In 2011, a majority of office-based physicians could exchange lab and medication data, and approximately one-third could exchange clinical summaries with patients or other providers. EHRs serve as a key mechanism by which physicians can exchange clinical data, though physicians' capability to exchange varies by vendor and by state.

Analysis of non-contact and contact probe-to-sample thermal exchange for quantitative measurements of thin film and nanostructure thermal conductivity by the scanning hot probe method

Science.gov (United States)

Wilson, Adam A.

The ability to measure thermal properties of thin films and nanostructured materials is an important aspect of many fields of academic study. A strategy especially well-suited for nanoscale investigations of these properties is the scanning hot probe technique, which is unique in its ability to non-destructively interrogate the thermal properties with high resolution, both laterally as well as through the thickness of the material. Strategies to quantitatively determine sample thermal conductivity depend on probe calibration. State of the art calibration strategies assume that the area of thermal exchange between probe and sample does not vary with sample thermal conductivity. However, little investigation has gone into determining whether or not that assumption is valid. This dissertation provides a rigorous study into the probe-to-sample heat transfer through the air gap at diffusive distances for a variety of values of sample thermal conductivity. It is demonstrated that the thermal exchange radius and gap/contact thermal resistance varies with sample thermal conductivity as well as tip-to-sample clearance in non-contact mode. In contact mode, it is demonstrated that higher thermal conductivity samples lead to a reduction in thermal exchange radius for Wollaston probe tips. Conversely, in non-contact mode and in contact mode for sharper probe tips where air contributes the most to probe-to-sample heat transfer, the opposite trend occurs. This may be attributed to the relatively strong solid-to-solid conduction occurring between probe and sample for the Wollaston probes. A three-dimensional finite element (3DFE) model was developed to investigate how the calibrated thermal exchange parameters vary with sample thermal conductivity when calibrating the probe via the intersection method in non-contact mode at diffusive distances. The 3DFE model was then used to explore the limits of sensitivity of the experiment for a range of simulated experimental conditions. It

Calorimetry exchange program annual data report for 1992

International Nuclear Information System (INIS)

Barnett, T.M.

1992-01-01

The goals of the Calorimetry Sample Exchange Program are: discuss measurement differences; review and improve analytical measurements and methods; discuss new measurement capabilities; provide data to DOE on measurement capabilities to evaluate shipper-receiver differences; provide characterized or standard materials as necessary for exchange participants; and provide a measurement control program for plutonium analysis. A sample of PuO 2 powder is available at each participating site for NDA measurement, including either or both calorimetry and high-resolution gamma-ray spectroscopy, the elements which are typically combined to provide a calorimetric assay of plutonium. The facilities measure the sample as frequently and to the level of precision which they desire, and then submit the data to the Exchange for analysis. The data report includes summary tables for each measurement and charts showing the performance of each laboratory. Comparisons are made to the accepted values for the exchange sample and to data previously reported by that laboratory. This information is presented, in the form of quarterly and annual reports, intended for use by Exchange participants in measurement control programs, or to indicate when bias corrections may be appropriate. No attempt, however, has been made to standardize methods or frequency of data collection, calibration, or operating procedures. Direct comparisons between laboratories may, therefore, be misleading since data have not been collected to the same precision or for the same time periods. A meeting of the participants of the Calorimetry Exchange is held annually at EG ampersand G Mound Applied Technologies. The purposes of this meeting are to discuss measurement differences, problems, and new measurement capabilities, and to determine the additional activities needed to fulfill the goals of the Exchange. This document provides data for 1992

Ion-Exchange Sample Displacement Chromatography as a Method for Fast and Simple Isolation of Low- and High-Abundance Proteins from Complex Biological Mixtures

Directory of Open Access Journals (Sweden)

Martina Srajer Gajdosik

2014-01-01

Full Text Available Sample displacement chromatography (SDC in reversed phase and ion-exchange modes was introduced at the end of 1980s. This chromatographic method was first used for preparative purification of synthetic peptides, and subsequently adapted for protein fractionation, mainly in anion-exchange mode. In the past few years, SDC has been successfully used for enrichment of low- and medium-abundance proteins from complex biological fluids on both monolithic and bulk chromatographic supports. If aqueous mobile phase is used with the application of mild chromatographic conditions, isolated proteins are not denatured and can also keep their biological activity. In this paper, the use of SDC in anion-exchange mode on a high-capacity chromatographic resin for separation of proteins from complex biological mixtures such as human plasma is demonstrated. By use of three and more columns coupled in series during sample application, and subsequent parallel elution of detached columns, additional separation of bound proteins was achieved. Highly enriched human serum albumin fraction and a number of physiologically active medium- and low-abundance proteins could be fractionated and detected by electrospray ionization tandem mass spectrometry (ESI-MS/MS and matrix assisted laser desorption/ionization time-of-flight tandem mass spectrometry (MALDI-TOF/TOF-MS. The use of the aforementioned columns that can be sanitized with 1 M sodium hydroxide for further application of SDC in biotechnology and food technology was discussed.

Error in interpreting field chlorophyll fluorescence measurements: heat gain from solar radiation

International Nuclear Information System (INIS)

Marler, T.E.; Lawton, P.D.

1994-01-01

Temperature and chlorophyll fluorescence characteristics were determined on leaves of various horticultural species following a dark adaptation period where dark adaptation cuvettes were shielded from or exposed to solar radiation. In one study, temperature of Swietenia mahagoni (L.) Jacq. leaflets within cuvettes increased from approximately 36C to approximately 50C during a 30-minute exposure to solar radiation. Alternatively, when the leaflets and cuvettes were shielded from solar radiation, leaflet temperature declined to 33C in 10 to 15 minutes. In a second study, 16 horticultural species exhibited a lower variable: maximum fluorescence (F v :F m ) when cuvettes were exposed to solar radiation during the 30-minute dark adaptation than when cuvettes were shielded. In a third study with S. mahagoni, the influence of self-shielding the cuvettes by wrapping them with white tape, white paper, or aluminum foil on temperature and fluorescence was compared to exposing or shielding the entire leaflet and cuvette. All of the shielding methods reduced leaflet temperature and increased the F v :F m ratio compared to leaving cuvettes exposed. These results indicate that heat stress from direct exposure to solar radiation is a potential source of error when interpreting chlorophyll fluorescence measurements on intact leaves. Methods for moderating or minimizing radiation interception during dark adaptation are recommended. (author)

Ion-exchanger ultraviolet spectrophotometry for uranium(VI)

International Nuclear Information System (INIS)

Waki, H.; Korkisch, J.

1983-01-01

A sensitive method based on solid-phase spectrophotometry has been developed for the microdetermination of uranium(VI) in water samples. Uranium is sorbed on the anion-exchanger QAE-Sephadex from thiocyanate solution and the absorbance of the exchanger is measured at 300 nm. This method is about 30 times more sensitive than solution spectrophotometry. Absorption spectra of various metals in the anion-exchanger phase are presented and their interferences discussed. A procedure for the cation-exchange separation of uranium from accompanying elements before spectral measurement of uranium is proposed. (author)

A replica exchange transition interface sampling method with multiple interface sets for investigating networks of rare events

Science.gov (United States)

Swenson, David W. H.; Bolhuis, Peter G.

2014-07-01

The multiple state transition interface sampling (TIS) framework in principle allows the simulation of a large network of complex rare event transitions, but in practice suffers from convergence problems. To improve convergence, we combine multiple state TIS [J. Rogal and P. G. Bolhuis, J. Chem. Phys. 129, 224107 (2008)] with replica exchange TIS [T. S. van Erp, Phys. Rev. Lett. 98, 268301 (2007)]. In addition, we introduce multiple interface sets, which allow more than one order parameter to be defined for each state. We illustrate the methodology on a model system of multiple independent dimers, each with two states. For reaction networks with up to 64 microstates, we determine the kinetics in the microcanonical ensemble, and discuss the convergence properties of the sampling scheme. For this model, we find that the kinetics depend on the instantaneous composition of the system. We explain this dependence in terms of the system's potential and kinetic energy.

Ion exchange in ZSM-5 zeolite

International Nuclear Information System (INIS)

Matthews, D.P.; Rees, L.V.C.

1986-01-01

The ion exchange properties of Na-ZSM5 have been studied using a number of univalent and divalent cations at 25degC and 65degC. All the univalent cations studied achieved 100 per cent exchange. The thermodynamic affinity sequence Cs > Rb=NH 4 =H 3 O>K>Na>Li was found at both temperatures for a sample with Si/Al=39. Standard enthalpies of exchange ΔH o were calculated using the van't' Hoff isochore and standard entropies of exchange were then calculated from ΔH o and ΔG o . Multivalent cations were unable to achieve 100 per cent exchange. The maximum exchange was found to increase through the series Ca 2+ cations ( 57 Fe enriched) on dehydration and rehydration following sorption and desorption of ethanol. At least 3 sites for Fe 2+ were observed in the dehydrated zeolite. (author)

Inorganic ion exchangers for nuclear waste remediation

Energy Technology Data Exchange (ETDEWEB)

Clearfield, A.; Bortun, A.; Bortun, L.; Behrens, E. [Texas A& M Univ., College Station, TX (United States)

1997-10-01

The objective of this work is to provide a broad spectrum of inorganic ion exchangers that can be used for a range of applications and separations involving remediation of groundwater and tank wastes. The authors intend to scale-up the most promising exchangers, through partnership with AlliedSignal Inc., to provide samples for testing at various DOE sites. While much of the focus is on exchangers for removal of Cs{sup +} and Sr{sup 2+} from highly alkaline tank wastes, especially at Hanford, the authors have also synthesized exchangers for acid wastes, alkaline wastes, groundwater, and mercury, cobalt, and chromium removal. These exchangers are now available for use at DOE sites. Many of the ion exchangers described here are new, and others are improved versions of previously known exchangers. They are generally one of three types: (1) layered compounds, (2) framework or tunnel compounds, and (3) amorphous exchangers in which a gel exchanger is used to bind a fine powder into a bead for column use. Most of these exchangers can be regenerated and used again.

DOES CURRENCY SUBSTITUTION AFFECT EXCHANGE RATE VOLATILITY?

Directory of Open Access Journals (Sweden)

Hisao Kumamoto

2014-10-01

Full Text Available This study investigates the impacts of the degree of currency substitution on nominal exchange rate volatility in seven countries (Indonesia, the Philippines, the Czech Republic, Hungary, Poland, Argentina, and Peru. We use the Threshold ARCH model to consider the ratchet effect of currency substitution and sample periods in the 2000s, during which time the economies of the sample countries stabilized, while the U.S. dollar and euro depreciated against other major currencies following the recent global financial crisis. The presented empirical analyses show that the degree of currency substitution has significant positive effects on the conditional variance of the depreciation rate of the nominal exchange rate in most sample countries. Moreover, a shock to the depreciation rate of the nominal exchange rate has asymmetric effects on the conditional variance, depending on the sign. One possible explanation for these differential effects is the existence of the ratchet effect of currency substitution.

A Bayesian Justification for Random Sampling in Sample Survey

Directory of Open Access Journals (Sweden)

Glen Meeden

2012-07-01

Full Text Available In the usual Bayesian approach to survey sampling the sampling design, plays a minimal role, at best. Although a close relationship between exchangeable prior distributions and simple random sampling has been noted; how to formally integrate simple random sampling into the Bayesian paradigm is not clear. Recently it has been argued that the sampling design can be thought of as part of a Bayesian's prior distribution. We will show here that under this scenario simple random sample can be given a Bayesian justification in survey sampling.

Alpha spetrometric determination of 226Ra in water samples by using ion exchanger MnO2-PAN

International Nuclear Information System (INIS)

Gardonova, V.; Dulanska, S.; Matel, L.; Bilohuscin, J.; Horvathova, B.; Sebesta, F.

2014-01-01

A method for 226 Ra preconcentration and separation from water samples using MnO 2 -PAN (polyacrylonitrile) ion absorber composite was proposed, optimized and verified. The optimization was focused on prevention of the destruction of MnO 2 -PAN composite absorber during radium elution from the column, testing of multiple use of the resin, influence of calcium concentration on radiochemical yields and application of the method for various types of water samples. Absorber was produced at Czech Technical University in Prague and now is also commercially available from Triskem International, France as MnO 2 -PAN Resin.This absorber with grain size (0.1-0.3) mm was used for 226 Ra preconcentration from various types of water samples at pH = (6.5-7.0). Radium was eluted from the ion exchanger MnO 2 -PAN with 20 mL of 6.5 mol/L HCl at flow rate of 1.5 mL/min. Samples were precipitated with Ba 2+ to form Ba(Ra)SO 4 microprecipitate for alpha spectrometry counting..The proposed method was applied to samples of natural mineral, mountain spring, drinking and natural healing waters from Slovakia, Slovenia and Czech Republic. Radium radiochemical recoveries were monitored by non-isotopic tracer 133 Ba and they were in the range of (92 - 100) %. The obtained 226 Ra activities in the analyzed samples were compared with the limit values set in Edict 528 of the Ministry of Health of the Slovak Republic in 2007 and no limit was exceeded. (authors)

Sorption of water vapour by the Na+-exchanged clay-sized fractions of some tropical soil samples

International Nuclear Information System (INIS)

Yormah, T.B.R.; Hayes, M.H.B.

1993-09-01

Water vapour sorption isotherms at 299K for the Na + -exchanged clay-sized (≤ 2μm e.s.d.) fraction of two sets of samples taken at three different depths from a tropical soil profile have been studied. One set of samples was treated (with H 2 O 2 ) for the removal of much of the organic matter (OM); the other set (of the same samples) was not so treated. The isotherms obtained were all of type II and analyses by the BET method yielded values for the Specific Surface Areas (SSA) and for the average energy of adsorption of the first layer of adsorbate (E a ). OM content and SSA for the untreated samples were found to decrease with depth. Whereas removal of organic matter made negligible difference to the SSA of the top/surface soil, the same treatment produced a significant increase in the SSA of the samples taken from the middle and from the lower depths in the profile; the resulting increase was more pronounced for the subsoil. It has been deduced from these results that OM in the surface soil was less involved with the inorganic soil colloids than that in the subsoil. The increase in surface area which resulted from the removal of OM from the subsoil was most probably due to disaggregation. Values of E a obtained show that for all the samples the adsorption of water vapour became more energetic after the oxidative removal of organic matter; the resulting ΔE a also increased with depth. This suggests that in the dry state, the ''cleaned'' surface of the inorganic soil colloids was more energetic than the ''organic-matter-coater surface''. These data provide strong support for the deduction that OM in the subsoil was in a more ''combined'' state than that in the surface soil. (author). 21 refs, 4 figs, 2 tabs

Replica exchange enveloping distribution sampling (RE-EDS): A robust method to estimate multiple free-energy differences from a single simulation.

Science.gov (United States)

Sidler, Dominik; Schwaninger, Arthur; Riniker, Sereina

2016-10-21

In molecular dynamics (MD) simulations, free-energy differences are often calculated using free energy perturbation or thermodynamic integration (TI) methods. However, both techniques are only suited to calculate free-energy differences between two end states. Enveloping distribution sampling (EDS) presents an attractive alternative that allows to calculate multiple free-energy differences in a single simulation. In EDS, a reference state is simulated which "envelopes" the end states. The challenge of this methodology is the determination of optimal reference-state parameters to ensure equal sampling of all end states. Currently, the automatic determination of the reference-state parameters for multiple end states is an unsolved issue that limits the application of the methodology. To resolve this, we have generalised the replica-exchange EDS (RE-EDS) approach, introduced by Lee et al. [J. Chem. Theory Comput. 10, 2738 (2014)] for constant-pH MD simulations. By exchanging configurations between replicas with different reference-state parameters, the complexity of the parameter-choice problem can be substantially reduced. A new robust scheme to estimate the reference-state parameters from a short initial RE-EDS simulation with default parameters was developed, which allowed the calculation of 36 free-energy differences between nine small-molecule inhibitors of phenylethanolamine N-methyltransferase from a single simulation. The resulting free-energy differences were in excellent agreement with values obtained previously by TI and two-state EDS simulations.

Spectrophotometric determination of chromium in geological samples

International Nuclear Information System (INIS)

Rathore, D.P.S.; Tarafder, P.K.

1992-01-01

A method for the determination of chromium is presented, based on the oxidation of hydroxylamine hydrochloride to nitrous acid by chromium(VI) in acetic acid medium followed by diazotization of the nitrite produced with p-aminophenylmercaptoacetic acid and subsequent coupling of the diazonium salt with N-(1-naphthyl)ethylenediamine di-hydrochloride in acidic medium to form a stable blueish azo dye. The method is suitable for the determination of chromium(VI) from 0.04 to 1.2 mg l -1 in a 1.0-cm cuvette. The molar absorptivity and Sandell's sensitivity are 3.65x10 4 l mol -1 cm -1 and 0.0014μg cm -2 , respectively. (author). 17 refs.; 3 figs

NMR magnetization exchange dynamics for three spin-1/2 systems

International Nuclear Information System (INIS)

Demco, D.E.; Filip, X.; Filip, C.

1997-01-01

The magnetization exchange dynamics in one-dimensional NMR exchange experiments performed with static samples is analyzed for the relevant case of three spin systems. The magnetization decays recorded in the experiments performed with different chemical shift filters for the short mixing times are derived analytically. In this regime the decay rates depend on the dipolar coupling between the spins belonging to different functional groups. The predictions of the theoretical model are compared with the magnetization exchange data obtained for cross-linked poly(styrene-co-butadiene) samples. The residual dipolar coupling between the functional CH- and CH2-groups of butadiene are measured from the magnetization exchange experiments in the short mixing time regime. (authors)

Asset sales, asset exchanges, and shareholder wealth in China

Directory of Open Access Journals (Sweden)

Weiting Huang

2012-01-01

Full Text Available In this paper, we study a sample of 1376 corporate asset sales and 250 asset exchanges in China between 1998 and 2006. We find that corporate asset sales in China enhance firm value with a cumulative abnormal return (CAR of 0.46% for the pre-announcement five-day period, which is consistent with the evidence discovered in both U.K. and U.S. For companies that exchanged assets during the sample period, the pre-announcement five-day CAR of 1.32% is statistically significant. We also discover that gains from divesting assets are positively related to managerial performance measured by Tobin's q ratio and the relative size of the asset sold or exchanged. Well-managed (high-q companies are more likely to sell or exchange assets in a value-maximizing fashion than poorly managed (low-q companies. Furthermore, asset-seller gains are not related to enhancing corporate focus, but improving corporate focus by exchanging for core assets enhances firm value.

Minutes of the 28th annual plutonium sample exchange meeting. Part I: isotopic sample exchange

International Nuclear Information System (INIS)

1984-01-01

Contents of this publication include the following: list of participating laboratories; agenda; attendees; minutes of October 24 meeting; and handout materials supplied by speakers. The handout materials cover the following: interlaboratory comparisons of plutonium isotope ratios. The plutonium ratios considered are 240/239, 241/239, 242/239, 238/239, 239/240, 241/240, 242/240, and 238/240; carbon, uranium, iron, and nickel data; mass spectroscopy data; determination of plutonium 241 half-life; review of plutonium overplating sample loading technique; on-line measurement evaluation system for isotopic analysis; and description of a new thermal ionization mass spectrometer

A Microplate Assay for the Determination of Hemoglobin Concentration

National Research Council Canada - National Science Library

Frenchik, Michael D; McFaul, Steve J; Tsonev, Latchezar I

2004-01-01

... (NaOH), and converts all hemoglobin species, including COHb, to AHD within 5 min. Both protocols are carried out in cuvettes, and are, therefore, time intensive and difficult to manage when many samples are quantified. This impedes acquisition of triplicate values for each sample necessary to improve accuracy and determine statistical significance.

Lipid exchange by ultracentrifugation

DEFF Research Database (Denmark)

Drachmann, Nikolaj Düring; Olesen, Claus

2014-01-01

, and the complex interplay between the lipids and the P-type ATPases are still not well understood. We here describe a robust method to exchange the majority of the lipids surrounding the ATPase after solubilisation and/or purification with a target lipid of interest. The method is based on an ultracentrifugation...... step, where the protein sample is spun through a dense buffer containing large excess of the target lipid, which results in an approximately 80-85 % lipid exchange. The method is a very gently technique that maintains protein folding during the process, hence allowing further characterization...

Biodegradation of ion-exchange media

International Nuclear Information System (INIS)

Bowerman, B.S.; Clinton, J.H.; Cowdery, S.R.

1988-08-01

Ion-exchange media, both bead resins and powdered filter media, are used in nuclear power plants to remove radioactivity from process water prior to reuse or environmental discharge. Since the ion- exchange media are made from synthetic hydrocarbon-based polymers, they may be susceptible to damage from biological activity. The purpose of this study was to investigate some of the more basic aspects of biodegradation of ion-exchange media, specifically to evaluate the ability of microorganisms to utilize the ion-exchange media or materials sorbed on them as a food source. The ASTM-G22 test, alone and combined with the Bartha Pramer respirometric method, failed to indicate the biodegradability of the ion-exchange media. The limitation of these methods was that they used a single test organism. In later phases of this study, a mixed microbial culture was grown from resin waste samples obtained from the BNL High Flux Beam Reactor. These microorganisms were used to evaluate the susceptibility of different types of ion-exchange media to biological attack. Qualitative assessments of biodegradability were based on visual observations of culture growths. Greater susceptibility was associated with increased turbidity in solution indicative of bacterial growth, and more luxuriant fungal mycelial growth in solution or directly on the ion-exchange resin beads. 21 refs., 9 figs., 18 tabs

Back-exchange: a novel approach to quantifying oxygen diffusion and surface exchange in ambient atmospheres.

Science.gov (United States)

Cooper, Samuel J; Niania, Mathew; Hoffmann, Franca; Kilner, John A

2017-05-17

A novel two-step Isotopic Exchange (IE) technique has been developed to investigate the influence of oxygen containing components of ambient air (such as H 2 O and CO 2 ) on the effective surface exchange coefficient (k*) of a common mixed ionic electronic conductor material. The two step 'back-exchange' technique was used to introduce a tracer diffusion profile, which was subsequently measured using Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS). The isotopic fraction of oxygen in a dense sample as a function of distance from the surface, before and after the second exchange step, could then be used to determine the surface exchange coefficient in each atmosphere. A new analytical solution was found to the diffusion equation in a semi-infinite domain with a variable surface exchange boundary, for the special case where D* and k* are constant for all exchange steps. This solution validated the results of a numerical, Crank-Nicolson type finite-difference simulation, which was used to extract the parameters from the experimental data. When modelling electrodes, D* and k* are important input parameters, which significantly impact performance. In this study La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ (LSCF6428) was investigated and it was found that the rate of exchange was increased by around 250% in ambient air compared to high purity oxygen at the same pO 2 . The three experiments performed in this study were used to validate the back-exchange approach and show its utility.

Determining the Exchange Rate: Purchasing Power Parity – PPP

Directory of Open Access Journals (Sweden)

Bangun WIDOYOKO

2018-05-01

Full Text Available This study aimed to examine the effect of inflation on the issue of exchange rate determination of the forward exchange rate on the exchange rate of RMB (Renminbi to Rupiah. Inflation has been chosen as an independent variable because of its close relation to PPP (purchasing power parity theory. Analyses in this research have used logistic analysis with time series data. The data that has been used include exchange rate data with the period 2007-2017 with a sample size of 132 data. The results of this study have shown that inflation is effective in determining the exchange rate.

Can positive social exchanges buffer the detrimental effects of negative social exchanges? Age and gender differences.

Science.gov (United States)

Fiori, Katherine L; Windsor, Tim D; Pearson, Elissa L; Crisp, Dimity A

2013-01-01

Findings from existing research exploring whether positive social exchanges can help to offset (or 'buffer' against) the harmful effects of negative social exchanges on mental health have been inconsistent. This could be because the existing research is characterized by different approaches to studying various contexts of 'cross-domain' and 'within-domain' buffering, and/or because the nature of buffering effects varies according to sociodemographic characteristics that underlie different aspects of social network structure and function. The purpose of this study was to examine whether the buffering effects of global perceptions of positive exchanges on the link between global negative exchanges and mental health varied as a function of age and gender. We used a series of regressions in a sample of 556 Australian older adults (ages 55-94) to test for three-way interactions among gender, positive social exchanges, and negative social exchanges, as well as age and positive and negative social exchanges, in predicting mental health, controlling for years of education, partner status, and physical functioning. We found that positive exchanges buffered against negative exchanges for younger old adults, but not for older old adults, and for women, but not for men. Our findings are interpreted in light of research on individual differences in coping responses and interpersonal goals among late middle-aged and older adults. Our findings are in line with gerontological theories (e.g., socioemotional selectivity theory), and imply that an intervention aimed at using positive social exchanges as a means of coping with negative social exchanges might be more successful among particular populations (i.e., women, 'younger' old adults). Copyright © 2012 S. Karger AG, Basel.

Interface adjustment and exchange coupling in the IrMn/NiFe system

Energy Technology Data Exchange (ETDEWEB)

Spizzo, F.; Tamisari, M.; Chinni, F.; Bonfiglioli, E.; Del Bianco, L., E-mail: lucia.delbianco@unife.it

2017-01-01

The exchange bias effect was investigated, in the 5–300 K temperature range, in samples of IrMn [100 Å]/NiFe [50 Å] (set A) and in samples with inverted layer-stacking sequence (set B), produced at room temperature by DC magnetron sputtering in a static magnetic field of 400 Oe. The samples of each set differ for the nominal thickness (t{sub Cu}) of a Cu spacer, grown at the interface between the antiferromagnetic and ferromagnetic layers, which was varied between 0 and 2 Å. It has been found out that the Cu insertion reduces the values of the exchange field and of the coercivity and can also affect their thermal evolution, depending on the stack configuration. Indeed, the latter also determines a peculiar variation of the exchange bias properties with time, shown and discussed with reference to the samples without Cu of the two sets. The results have been explained considering that, in this system, the exchange coupling mechanism is ruled by the glassy magnetic behavior of the IrMn spins located at the interface with the NiFe layer. Varying the stack configuration and t{sub Cu} results in a modulation of the structural and magnetic features of the interface, which ultimately affects the spins dynamics of the glassy IrMn interfacial component. - Highlights: • Exchange bias effect in IrMn/NiFe samples with interfacial Cu spacer. • A variation of exchange bias with time is observed in as-deposited samples. • Magnetic modification of the interface by varying the stack sequence and Cu thickness. • Interface adjustment affects the dynamics of interfacial IrMn spins. • The exchange bias properties can be tuned by interface adjustment.

Natural clinoptilolite exchanged with iron: characterization and catalytic activity in nitrogen monoxide reduction

Directory of Open Access Journals (Sweden)

Daria Tito-Ferro

2016-12-01

Full Text Available The aim of this work was to characterize the natural clinoptilolite from Tasajeras deposit, Cuba, modified by hydrothermal ion-exchange with solutions of iron (II sulfate and iron (III nitrate in acid medium. Besides this, its catalytic activity to reduce nitrogen monoxide with carbon monoxide/propene in the presence of oxygen was evaluated. The characterization was performed by Mössbauer and UV-Vis diffuse reflectance spectroscopies and adsorption measurements. The obtained results lead to conclude that in exchanged samples, incorporated divalent and trivalent irons are found in octahedral coordination. Both irons should be mainly in cationic extra-framework positions inside clinoptilolite channels as charge compensating cations, and also as iron oxy-hydroxides resulting from limited hydrolysis of these cations. The iron (III exchanged samples has a larger amount of iron oxy-hydroxides agglomerates. The iron (II exchanged samples have additionally iron (II sulfate adsorbed. The catalytic activity in the nitrogen monoxide reduction is higher in the exchanged zeolites than starting. Among all samples, those exchanged of iron (II has the higher catalytic activity. This lead to outline that, main catalytically active centers are associated with divalent iron.

IXM gas sampling procedure

International Nuclear Information System (INIS)

Pingel, L.A.

1995-01-01

Ion Exchange Modules (IXMs) are used at the 105-KE and -KW Fuel Storage Basins to control radionuclide concentrations in the water. A potential safety concern relates to production of hydrogen gas by radiolysis of the water trapped in the ion exchange media of spent IXMs. This document provides a procedure for sampling the gases in the head space of the IXM

Mycological studies housed in the Apollo 16 microbial ecology evaluation device

Science.gov (United States)

Volz, P. A.

1973-01-01

Survival, death, and phenotype count have yielded variation in the number of fungi recovered from the controls and the flight exposed cuvettes during preliminary analysis of postflight first phase data. Also the preliminary analysis was indicative that fungi exposed to specific space flight conditions demonstrated variable survival rates and phenotype counts. Specific space flight conditions included full light space exposure for Chaetomium globosum, exposure at 300- and 254-nanometer wavelengths for Rhodotorula rubra, full light and 280-nanometer wavelength exposure for Trichophyton terrestre, and 254-nanometer wavelength exposure for Saccharomyces cerevisiae. In general, phenotype counts for flight cuvettes and survival rates for control cuvettes were higher compared with the remaining cuvettes.

Charge exchange in galaxy clusters

Science.gov (United States)

Gu, Liyi; Mao, Junjie; de Plaa, Jelle; Raassen, A. J. J.; Shah, Chintan; Kaastra, Jelle S.

2018-03-01

Context. Though theoretically expected, the charge exchange emission from galaxy clusters has never been confidently detected. Accumulating hints were reported recently, including a rather marginal detection with the Hitomi data of the Perseus cluster. As previously suggested, a detection of charge exchange line emission from galaxy clusters would not only impact the interpretation of the newly discovered 3.5 keV line, but also open up a new research topic on the interaction between hot and cold matter in clusters. Aim. We aim to perform the most systematic search for the O VIII charge exchange line in cluster spectra using the RGS on board XMM-Newton. Methods: We introduce a sample of 21 clusters observed with the RGS. In order to search for O VIII charge exchange, the sample selection criterion is a >35σ detection of the O VIII Lyα line in the archival RGS spectra. The dominating thermal plasma emission is modeled and subtracted with a two-temperature thermal component, and the residuals are stacked for the line search. The systematic uncertainties in the fits are quantified by refitting the spectra with a varying continuum and line broadening. Results: By the residual stacking, we do find a hint of a line-like feature at 14.82 Å, the characteristic wavelength expected for oxygen charge exchange. This feature has a marginal significance of 2.8σ, and the average equivalent width is 2.5 × 10-4 keV. We further demonstrate that the putative feature can be barely affected by the systematic errors from continuum modeling and instrumental effects, or the atomic uncertainties of the neighboring thermal lines. Conclusions: Assuming a realistic temperature and abundance pattern, the physical model implied by the possible oxygen line agrees well with the theoretical model proposed previously to explain the reported 3.5 keV line. If the charge exchange source indeed exists, we expect that the oxygen abundance could have been overestimated by 8-22% in previous X

Hydrogen/deuterium exchange in mass spectrometry.

Science.gov (United States)

Kostyukevich, Yury; Acter, Thamina; Zherebker, Alexander; Ahmed, Arif; Kim, Sunghwan; Nikolaev, Eugene

2018-03-30

The isotopic exchange approach is in use since the first observation of such reactions in 1933 by Lewis. This approach allows the investigation of the pathways of chemical and biochemical reactions, determination of structure, composition, and conformation of molecules. Mass spectrometry has now become one of the most important analytical tools for the monitoring of the isotopic exchange reactions. Investigation of conformational dynamics of proteins, quantitative measurements, obtaining chemical, and structural information about individual compounds of the complex natural mixtures are mainly based on the use of isotope exchange in combination with high resolution mass spectrometry. The most important reaction is the Hydrogen/Deuterium exchange, which is mainly performed in the solution. Recently we have developed the approach allowing performing of the Hydrogen/Deuterium reaction on-line directly in the ionization source under atmospheric pressure. Such approach simplifies the sample preparation and can accelerate the exchange reaction so that certain hydrogens that are considered as non-labile will also participate in the exchange. The use of in-ionization source H/D exchange in modern mass spectrometry for structural elucidation of molecules serves as the basic theme in this review. We will focus on the mechanisms of the isotopic exchange reactions and on the application of in-ESI, in-APCI, and in-APPI source Hydrogen/Deuterium exchange for the investigation of petroleum, natural organic matter, oligosaccharides, and proteins including protein-protein complexes. The simple scenario for adaptation of H/D exchange reactions into mass spectrometric method is also highlighted along with a couple of examples collected from previous studies. © 2018 Wiley Periodicals, Inc.

Nickel speciation and complexation kinetics in freshwater by ligand exchange and DPCSV

NARCIS (Netherlands)

Han Bin Xue,; Jansen, S.; Prasch, A.; Sigg, L.

2001-01-01

A technique of ligand exchange with DMG (dimethylglyoxime) and DPCSV was applied to determine Ni speciation in lake, river, and groundwater samples. The working conditions related to ligand-exchange equilibrium were optimized, and the ligand-exchange kinetics were examined. The observed

Speciative determination of phosphorus in environmental water by the isotope exchange method

International Nuclear Information System (INIS)

Ikeda, N.; Yoshikawa, M.; Murakami, S.; Kunika, J.

1988-01-01

An isotope exchage method for the speciative determination of phosphorus (PO 4 3- ,PO 3 3- and total P) in natural water samples is proposed by using the exchange system of molybdophosphate in the aqueous phase and tetraphenylarsonium molybdophosphate in the organic phase. In this exchange system, only PO 4 3- exchanges and is determined. When the sample water is treated with Br 2 water in advance, the amount of PO 4 3- +PO 3 3- can be obtained. When the sample is treated with H 2 SO 4 and HNO 3 , the amount of total P can be determined. (author) 4 refs.; 5 tabs

Research of thermal stability of ion exchangers

International Nuclear Information System (INIS)

Stuchlik, S.; Srnkova, J.

1983-01-01

Prior to the fixation of radioactive ion exchangers into bitumen these exchangers have to be dried. The resulting gaseous products may generate explosive mixtures. An analysis was made of the thermal stability of two types of ion exchangers, the cation exchanger KU-2-8 cS and the anion exchanger AV-17-8 cS which are used in the V-1 nuclear power plant at Jaslovske Bohunice. The thermal stability of the anion exchangers was monitored using gas chromatography at temperatures of 100, 120, 140, 160 and 180 degC and by measuring weight loss by kiln-drying at temperatures of 120, 140, 160 and 180 degC. The ion exchanger was heated for 6 hours and samples were taken continuously at one hour intervals. The thermal stability of the cation exchanger was monitored by measuring the weight loss. Gas chromatography showed the release of trimethylamine from the anion exchanger in direct dependence on temperature. The measurement of weight losses, however, only showed higher losses of released products which are explained by the release of other thermally unstable products. The analysis of the thermal stability of the cation exchanger showed the release of SO 2 and the weight loss (following correction for water content) was found only after the fourth hour of decomposition. The experiment showed that the drying of anion exchanger AV-17-8 cS may cause the formation of explosive mixtures. (J.P.)

Timing Foreign Exchange Markets

Directory of Open Access Journals (Sweden)

Samuel W. Malone

2016-03-01

Full Text Available To improve short-horizon exchange rate forecasts, we employ foreign exchange market risk factors as fundamentals, and Bayesian treed Gaussian process (BTGP models to handle non-linear, time-varying relationships between these fundamentals and exchange rates. Forecasts from the BTGP model conditional on the carry and dollar factors dominate random walk forecasts on accuracy and economic criteria in the Meese-Rogoff setting. Superior market timing ability for large moves, more than directional accuracy, drives the BTGP’s success. We explain how, through a model averaging Monte Carlo scheme, the BTGP is able to simultaneously exploit smoothness and rough breaks in between-variable dynamics. Either feature in isolation is unable to consistently outperform benchmarks throughout the full span of time in our forecasting exercises. Trading strategies based on ex ante BTGP forecasts deliver the highest out-of-sample risk-adjusted returns for the median currency, as well as for both predictable, traded risk factors.

Martingale Regressions for a Continuous Time Model of Exchange Rates

OpenAIRE

Guo, Zi-Yi

2017-01-01

One of the daunting problems in international finance is the weak explanatory power of existing theories of the nominal exchange rates, the so-called “foreign exchange rate determination puzzle”. We propose a continuous-time model to study the impact of order flow on foreign exchange rates. The model is estimated by a newly developed econometric tool based on a time-change sampling from calendar to volatility time. The estimation results indicate that the effect of order flow on exchange rate...

A counter-intuitive approach to calculating non-exchangeable 2H isotopic composition of hair: treating the molar exchange fraction fE as a process-related rather than compound-specific variable

Science.gov (United States)

Landwehr, J.M.; Meier-Augenstein, W.; Kemp, H.F.

2011-01-01

Hair is a keratinous tissue that incorporates hydrogen from material that an animal consumes but it is metabolically inert following synthesis. The stable hydrogen isotope composition of hair has been used in ecological studies to track migrations of mammals as well as for forensic and archaeological purposes to determine the provenance of human remains or the recent geographic life trajectory of living people. Measurement of the total hydrogen isotopic composition of a hair sample yields a composite value comprised of both metabolically informative, non-exchangeable hydrogen and exchangeable hydrogen, with the latter reflecting ambient or sample preparation conditions. Neither of these attributes is directly measurable, and the non-exchangeable hydrogen composition is obtained by estimation using a commonly applied mathematical expression incorporating sample measurements obtained from two distinct equilibration procedures. This commonly used approach treats the fraction of exchangeable hydrogen as a mixing ratio, with a minimal procedural fractionation factor assumed to be close or equal to 1. Instead, we propose to use full molar ratios to derive an expression for the non-exchangeable hydrogen composition explicitly as a function of both the procedural fractionation factor α and the molar hydrogen exchange fraction fE. We apply these derivations in a longitudinal study of a hair sample and demonstrate that the molar hydrogen exchange fraction fE should, like the procedural fractionation factor α, be treated as a process-dependent parameter, i.e. a reaction-specific constant. This is a counter-intuitive notion given that maximum theoretical values for the molar hydrogen exchange fraction fE can be calculated that are arguably protein-type specific and, as such, fE could be regarded as a compound-specific constant. We also make some additional suggestions for future approaches to determine the non-exchangeable hydrogen composition of hair and the use of

Forecasting Exchange Rate Volatility in the Presence of Jumps

DEFF Research Database (Denmark)

Busch, Thomas; Christensen, Bent Jesper; Nielsen, Morten Ørregaard

We study measures of foreign exchange rate volatility based on high-frequency (5-minute) $/DM exchange rate returns using recent nonparametric statistical techniquesto compute realized return volatility and its separate continuous sample path and jumpcomponents, and measures based on prices...... of exchange rate futures options, allowingcalculation of option implied volatility. We find that implied volatility is an informationallyefficient but biased forecast of future realized exchange rate volatility. Furthermore,we show that log-normality is an even better distributional approximation...... for impliedvolatility than for realized volatility in this market. Finally, we show that the jump componentof future realized exchange rate volatility is to some extent predictable, and thatoption implied volatility is the dominant forecast of the future jump component....

Isotopic exchange of carbon-bound hydrogen over geologic timescales

Science.gov (United States)

Sessions, Alex L.; Sylva, Sean P.; Summons, Roger E.; Hayes, John M.

2004-04-01

The increasing popularity of compound-specific hydrogen isotope (D/H) analyses for investigating sedimentary organic matter raises numerous questions about the exchange of carbon-bound hydrogen over geologic timescales. Important questions include the rates of isotopic exchange, methods for diagnosing exchange in ancient samples, and the isotopic consequences of that exchange. This article provides a review of relevant literature data along with new data from several pilot studies to investigate such issues. Published experimental estimates of exchange rates between organic hydrogen and water indicate that at warm temperatures (50-100°C) exchange likely occurs on timescales of 104 to 108 yr. Incubation experiments using organic compounds and D-enriched water, combined with compound-specific D/H analyses, provide a new and highly sensitive method for measuring exchange at low temperatures. Comparison of δD values for isoprenoid and n-alkyl carbon skeletons in sedimentary organic matter provides no evidence for exchange in young (exchange in ancient (>350 Ma) rocks. Specific rates of exchange are probably influenced by the nature and abundance of organic matter, pore-water chemistry, the presence of catalytic mineral surfaces, and perhaps even enzymatic activity. Estimates of equilibrium fractionation factors between organic H and water indicate that typical lipids will be depleted in D relative to water by ∼75 to 140‰ at equilibrium (30°C). Thus large differences in δD between organic molecules and water cannot be unambiguously interpreted as evidence against hydrogen exchange. A better approach may be to use changes in stereochemistry as a proxy for hydrogen exchange. For example, estimated rates of H exchange in pristane are similar to predicted rates for stereochemical inversion in steranes and hopanes. The isotopic consequences of this exchange remain in question. Incubations of cholestene with D2O indicate that the number of D atoms incorporated during

Reduction of molecular gas diffusion through gaskets in leaf gas exchange cuvettes by leaf‐mediated pores

DEFF Research Database (Denmark)

Boesgaard, Kristine Stove; Mikkelsen, Teis Nørgaard; Ro‐Poulsen, Helge

2013-01-01

material such as grass leaves with circular cross section, and the effectiveness is shown with respiration measurements on a harp of Deschampsia flexuosa leaves. We conclude that the best solution for measurements with portable photosynthesis systems is to avoid LMP rather than trying to correct...

A Firm-Specific Analysis of the Exchange-Rate Exposure of Dutch Firms

NARCIS (Netherlands)

A. de Jong (Abe); J. Ligterink; V. Macrae

2002-01-01

textabstractWe examine the relationship between exchange-rate changes and stock returns for a sample of Dutch firms over 1994-1998. We find that over 50% of the firms are significantly exposed to exchange-rate risk. Furthermore, all firms with significant exchange-rate exposure benefit from a

Effects of electron beam irradiation on inorganic exchanger AMP

International Nuclear Information System (INIS)

Rao, K.L.N.; Mathew, C.; Deshpande, R.S.; Jadhav, A.V.; Pande, B.M.; Shukla, J.P.

1996-01-01

The heteropolyacid salt inorganic exchanger ammonium molybdophosphate (AMP) was subjected to an electron dose upto 2 MGy to assess any possible radiation damage. The breakthrough and total exchange capacity of AMP for Cs + from simulated fission product solutions were determined for both control and irradiated samples. The scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDX) were deployed to examine any marked microscopic changes taking place in this exchanger. (author). 3 refs., 3 figs

Intergenerational Exchange and Subjective Well-being among the Elderly.

Science.gov (United States)

Lee, Gary R.; Ellithorpe, Eugene

1982-01-01

Focused on the exchange of aid between older persons and their children. Hypotheses regarding relationships between mutual aid and the morale of the elderly were developed and tested on a sample of 403 parents aged 60 and over. No relationships between morale and the exchange of aid were found. (Author)

Basic exchangeable cations in Finnish mineral soils

Directory of Open Access Journals (Sweden)

Armi Kaila

1972-09-01

Full Text Available The content of exchangeable Ca, Mg, K and Na replaced by neutral ammonium acetate was determined in 470 samples of mineral soils from various parts of Finland, except from Lapland. The amount of all these cations tended to increase with an increase in the clay content, but variation within each textural class was large, and the ranges usually overlapped those of the other classes. The higher acidity of virgin surface soils was connected with a lower average degree of saturation by Ca as compared with the corresponding textural classes of cultivated soils. No significant difference in the respective contents of other cations was detected. The samples of various textural groups from deeper layers were usually poorer in exchangeable Ca and K than the corresponding groups of plough layer. The mean content of exchangeable Mg was equal or even higher in the samples from deeper layers than in the samples from plough layer, except in the group of sand soils. The percentage of Mg of the effective CEC increased, as an average, from 9 in the sand and fine sand soils of plough layer to 30 in the heavy clay soils; in the heavy clay soils from deeper layers its mean value was 38 ± 4 %. In the samples of plough layer, the mean ratio of Ca to Mg in sand and fine sand soils was about 9, in silt and loam soils about 6, in the coarser clay soils about 4, and in heavy clay about 2.

Study of the isotopic exchange associated with ionic exchange for the radiochemical separation of 233-Th

International Nuclear Information System (INIS)

Sepulveda Munita, C.J.A.

1983-01-01

The isotopic ion exchange procedure is applied in order to establish an analytical method for the determination of thorium by means of the 233 Th activity, when the presence of interfering elements does not allow a direct non-destructive activation analysis. The separation is based on the retention of 233 Th by a thorium saturated resin, due to the isotopic exchange effect, and subsequent elution of the interfering radioisotopes with a solution of thorium in diluted hydrochloric acid. The interfering elements were those which either present a great affinity for the resin or emit gamma rays with energies close to that of 233 Th (86.6 KeV), when a NaI(Tl) detector is used to obtain the gama-ray spectra of the irradiated samples. The equilibrium time for the thorium isotopic ion exchange and the distribution coefficients for the interfering elements were determined by using Bio-Rad AG 50W resins (100-200 mesh), with 4% to 8% of divinylbenzene. The best separation conditions were established in terms of the thorium and hydrochloric acid concentrations in the solution, the resin cross-linking degree, and the solution flow through the resin. The analytical method was applied to the determination of thorium in samples of ammonium diuranate as well in standard rock samples from the United States Geological Survey. The sensitivity, precision and accuracy of the method are also discussed. (Author) [pt

Collagen proteins exchange O with demineralisation and gelatinisation reagents and also with atmospheric moisture.

Science.gov (United States)

von Holstein, Isabella; von Tersch, Matthew; Coutu, Ashley N; Penkman, Kirsty E H; Makarewicz, Cheryl A; Collins, Matthew J

2018-01-23

The oxygen isotope composition of collagen proteins is a potential indicator of adult residential location, useful for provenancing in ecology, archaeology and forensics. In acidic solution, proteins can exchange O from carboxylic acid moieties with reagent O. This study investigated whether this exchange occurs during demineralisation and gelatinisation preparation of bone/ivory collagen. EDTA and HCl demineralisation or gelatinisation reagents were made up in waters with different δ 18 O values, and were used to extract collagen from four skeletal tissue samples. Aliquots of extracted collagen were exposed to two different atmospheric waters, at 120°C and ambient temperature, and subsequently dried in a vacuum oven at 40°C or by freeze drying. Sample δ 18 O values were measured by HT/EA pyrolysis-IRMS using a zero-blank autosampler. Collagen samples exchanged O with both reagent waters and atmospheric water, which altered sample δ 18 O values. Exchange with reagent waters occurred in all extraction methods, but was greater at lower pH. Damage to the collagen samples during extraction increased O exchange. The nature of exchange of O with atmospheric water depended on the temperature of exposure: kinetic fractionation of O was identified at 120°C but not at ambient temperature. Exchange was difficult to quantify due to high variability of δ 18 O value between experimental replicates. Studies of δ 18 O values in collagen proteins should avoid extraction methods using acid solutions. This article is protected by copyright. All rights reserved.

Automated ion-exchange system for the radiochemical separation of the noble metals

International Nuclear Information System (INIS)

Parry, S.J.

1980-01-01

Ion-exchange separation is particularly suitable for mechanisation and automated ion exchange has been applied to the activation analysis of biological and environmental samples. In this work a system has been designed for experimental studies, which can be adapted for different modes of operation. The equipment is based on a large-volume sampler for the automatic presentation of 500 ml of liquid to a sampling probe. The sample is delivered to the ion-exchange column by means of a peristaltic pump. The purpose of this work was to automate a procedure for separating the noble metals from irradiated geological samples, for neutron-activation analysis. The process of digesting the rock sample is carried out manually in 30 min and is not suited to unattended operation. The volume of the resulting liquid sample may be 100 ml and so the manual separation step may take as long as 1.25 h per sample. The reason for automating this part of the procedure is to reduce the separation time for a group of five samples and consequently to improve the sensitivity of the analysis for radionuclides with short half-lives. This paper describes the automatic ion-exchange system and the ways in which it can be used. The mode of operation for the separation of the noble metals is given in detail. The reproducibility of the system has been assessed by repeated measurements on a standard reference matte. (author)

Exchange rate policy and external debt in emerging economies: an empirical analysis

OpenAIRE

Cebir, Bilgen

2012-01-01

In this thesis, we empirically analyze the e ects of exchange rate policy on external debt accumulation in emerging market economies with a sample of 15 countries over the period 1998-2010. The exchange rate policy is captured by the de facto exchange rate classi cation of Ilzetzki, Reinhart, and Rogo (2008). This classification is based on the actual exchange rate behavior rather than the officially declared regimes. Therefore, it is expected to better reflect the exchange rate policies act...

Common factors and the exchange rate: results from the Brazilian case

Directory of Open Access Journals (Sweden)

Wilson Rafael de Oliveira Felício

2014-03-01

Full Text Available This paper studies the usefulness of factor models in explaining the dynamics of the exchange rate Real / Dollar from January 1999 to August 2011. The paper verifies that the inclusion of factors embedded on the common movements of exchange rates of a set of countries significantly improves the in-sample and out-of-sample predictive power of the models comprising only macroeconomic fundamentals commonly used in the literature to forecast the exchange rate. The paper also links the information contained in the factors to global shocks like the demand for dollars - a "dollar effect", volatility and liquidity of global financial markets.

The selectivity of zirconium phosphate for caesium in electrochemical ion exchange

International Nuclear Information System (INIS)

Lain, M.J.

1988-11-01

The properties of amorphous zirconium phosphate are investigated as an inorganic ion exchanger for use in liquid waste treatment by electrochemical ion exchange. Experiments to determine and increase the selectivity for caesium exchange over sodium are discussed, including various pulsed waveforms and studies with rotating membranes. Automation of a sampling system with pH and atomic absorption measurements is described. (author)

Preparation and characterization of zirconium phosphate ion exchanger samples with respect to the separation of highly active actinoid elements

International Nuclear Information System (INIS)

Treplan, J.

1972-01-01

Inorganic ion exchangers are of growing interest in connection with separation processes of α-radiators of high specific activity, or with high gamma doses, because they have a considerably higher radiation resistance at their disposal compared to the commonly used organic ion exchangers. In opposition to their use, however, are the worse properties regarding capacity, chemical resistivity, exchange rate and reproducibility of the ion exchange bed. In the present work, an attempt has been made to influence the properties of a typical representative of this group, zirconium phosphate (ZP), by systematic changing of the preparation parameters in such a manner that a sufficient capacity is obtained regarding tri-valent ions. In addition, information is to be gathered in order to clarify the connection between exchanger property and structure of the ZP. (orig./LH) [de

Synthesis and characterization of cobalt ferrocyanides loaded on organic anion exchanger

Energy Technology Data Exchange (ETDEWEB)

Valsala, T.P. [Waste Management Division, Bhabha Atomic Research Centre, Trombay 400 085 (India)], E-mail: tpvalsala@yahoo.co.in; Joseph, Annie [Waste Management Division, Bhabha Atomic Research Centre, Trombay 400 085 (India); Shah, J.G. [Back End Technology Division, Bhabha Atomic Research Centre, Trombay 400 085 (India); Raj, Kanwar [Waste Management Division, Bhabha Atomic Research Centre, Trombay 400 085 (India); Venugopal, V. [Radiochemistry and Isotope Group, Bhabha Atomic Research Centre, Trombay 400 085 (India)

2009-02-15

Transition metal ferrocyanides have important applications in the selective removal of radioactive caesium from low level and intermediate level radioactive liquid waste streams. The microcrystalline nature of these materials renders them useless for application in column mode operations. Special preparation procedures have been developed to prepare granular solids by in situ precipitation of metal ferrocyanides on organic anion exchangers, which is suitable for column mode operations. The elemental compositions of the metal ferrocyanides precipitated inside the pores of anion exchanger were determined by analysing the dissolved samples using ICP-AES system and flame photometer. From the XRD and EDX analyses and the elemental composition of the synthesized materials, the nature of the compound formed inside the anion exchanger was found to be cobalt ferrocyanide. From SEM analysis of the samples, the particle size of the cobalt ferrocyanide precipitated inside the anion exchanger was found to be much less than that of cobalt ferrocyanide precipitated outside. The efficiency of these materials for removal of Cs was evaluated by measuring the distribution coefficient (Kd), ion exchange capacity and kinetics of Cs uptake. The Kd of the materials loaded on anion exchanger was found to be of the order of 10{sup 5} ml/g. The Cs uptake kinetics of the materials loaded on anion exchanger was slower than that of precipitated materials. The ion exchange capacity of the cobalt ferrocyanide loaded on anion exchanger was found to be much higher than that of the precipitated cobalt ferrocyanide.

New Trends in Magnetic Exchange Bias

Science.gov (United States)

Mougin, Alexandra; Mangin, Stéphane; Bobo, Jean-Francois; Loidl, Alois

2005-05-01

of the constituant layers. The spirit of this topical issue is, for the first time, to gather and survey recent and original developments, both experimental and theoretical, which bring new insights into the physics of exchange bias. It has been planned in relation with an international workshop exclusively devoted to exchange bias, namely IWEBMN’04 (International Workshop on Exchange Bias in Magnetic Nanostructures) that took place in Anglet, in the south west of France, from 16th to 18th September 2004. The conference gathered worldwide researchers in the area, both experimentalists and theoreticians. Several research paths are particularly active in the field of magnetic exchange coupling. The conference, as well as this topical issue, which was also open to contributions from scientists not participating in the conference, has been organized according to the following principles: 1. Epitaxial systems: Since the essential behavior of exchange bias critically depends on the atomic-level chemical and spin structure at the interface between the ferromagnetic and antiferromagnetic components, epitaxial AF/F systems in which the quality of the interface and the crystalline coherence are optimized and well known are ideal candidates for a better understanding of the underlying physics of exchange bias. The dependence of exchange bias on the spin configurations at the interfaces can be accomplished by selecting different crystallographic orientations. The role of interface roughness can also be understood from thin-film systems by changing the growth parameters, and correlations between the interface structure and exchange bias can be made, as reported in this issue. 2. Out-of-plane magnetized systems: While much important work has been devoted to the study of structures with in-plane magnetization, little has been done on the study of exchange bias and exchange coupling in samples with out-of-plane magnetization. Some systems can exhibit either in-plane or out

Using Ion Exchange Chromatography to Separate and Quantify Complex Ions

Science.gov (United States)

Johnson, Brian J.

2014-01-01

Ion exchange chromatography is an important technique in the separation of charged species, particularly in biological, inorganic, and environmental samples. In this experiment, students are supplied with a mixture of two substitution-inert complex ions. They separate the complexes by ion exchange chromatography using a "flash"…

Assessing the Sodium Exchange Capacity in Rainfed and Irrigated Soils in the Mediterranean Basin Using GIS

Directory of Open Access Journals (Sweden)

Luís Loures

2017-03-01

Full Text Available The soil exchange complex consists of colloidal materials on which ion exchange phenomena occur allowing it to attract, retain, and exchange elements that have opposite electric charges. Since their mineral constituents (clay and organic components (humus are mainly of a negative nature retained or exchanged ion are predominantly cations. Historically, failing to monitor parameters like the exchange sodium percentage (ESP has led to the permanent deterioration of soils which have become completely unproductive, largely reducing the sustainability of the agricultural systems. This study assesses how the sodium exchange capacity in irrigated soils differs from the rainfed ones through a sample survey that was carried out in the 15,031 ha of the Caia Irrigation Perimeter and adjacent areas, located in the municipalities of Elvas and Campo Maior, Portalegre District, Portugal where 14,280 georeferenced samples were collected from the top soil layer (0–20 cm, which were mixed 10 at a time so that each composite sample representing 11.1 ha. Then the samples were analyzed regarding the most relevant parameters for characterizing the soil exchange complex including the concentrations of exchanged bases and Cation Exchange Capacity (CEC. The results were arranged in a georeferenced grid with 1451 entries. Using classical statistical analysis and Geographic Information Systems (GIS software, it was possible to relate the individual soil samples analyzed with the cultural system practiced (irrigated or rainfed and the present soil group which permitted us to analyze the influence of the cultural system in the soil exchange complex. The distribution chart of the exchange sodium and CEC were created. The obtained results confirm a general decrease of CEC values and an increase of the exchangeable sodium content of irrigated explored soils when compared to the rainfed ones, putting forward noteworthy ideas not only regarding the necessary changes towards

Coulomb replica-exchange method: handling electrostatic attractive and repulsive forces for biomolecules.

Science.gov (United States)

Itoh, Satoru G; Okumura, Hisashi

2013-03-30

We propose a new type of the Hamiltonian replica-exchange method (REM) for molecular dynamics (MD) and Monte Carlo simulations, which we refer to as the Coulomb REM (CREM). In this method, electrostatic charge parameters in the Coulomb interactions are exchanged among replicas while temperatures are exchanged in the usual REM. By varying the atom charges, the CREM overcomes free-energy barriers and realizes more efficient sampling in the conformational space than the REM. Furthermore, this method requires only a smaller number of replicas because only the atom charges of solute molecules are used as exchanged parameters. We performed Coulomb replica-exchange MD simulations of an alanine dipeptide in explicit water solvent and compared the results with those of the conventional canonical, replica exchange, and van der Waals REMs. Two force fields of AMBER parm99 and AMBER parm99SB were used. As a result, the CREM sampled all local-minimum free-energy states more frequently than the other methods for both force fields. Moreover, the Coulomb, van der Waals, and usual REMs were applied to a fragment of an amyloid-β peptide (Aβ) in explicit water solvent to compare the sampling efficiency of these methods for a larger system. The CREM sampled structures of the Aβ fragment more efficiently than the other methods. We obtained β-helix, α-helix, 3(10)-helix, β-hairpin, and β-sheet structures as stable structures and deduced pathways of conformational transitions among these structures from a free-energy landscape. Copyright © 2012 Wiley Periodicals, Inc.

The Dynamics of Foreign Exchange Rate Risk Management in Different Enterprises

OpenAIRE

Khaldoun M. Al-Qaisi

2012-01-01

Foreign currency exchange management is very crucial in firms with foreign deals. The objective of this research was to study the management practices in Jordanian firms of foreign exchange management and its risk on these firms. A questionnaire was used to collect data using a stratified random sample. The results show that the firms interested with foreign currency exchange management as it forms more that 50% of its deals. Most of firms indicated that they have a policy for foreign exchang...

SPEEDUPtrademark ion exchange column model

International Nuclear Information System (INIS)

Hang, T.

2000-01-01

A transient model to describe the process of loading a solute onto the granular fixed bed in an ion exchange (IX) column has been developed using the SpeedUptrademark software package. SpeedUp offers the advantage of smooth integration into other existing SpeedUp flowsheet models. The mathematical algorithm of a porous particle diffusion model was adopted to account for convection, axial dispersion, film mass transfer, and pore diffusion. The method of orthogonal collocation on finite elements was employed to solve the governing transport equations. The model allows the use of a non-linear Langmuir isotherm based on an effective binary ionic exchange process. The SpeedUp column model was tested by comparing to the analytical solutions of three transport problems from the ion exchange literature. In addition, a sample calculation of a train of three crystalline silicotitanate (CST) IX columns in series was made using both the SpeedUp model and Purdue University's VERSE-LC code. All test cases showed excellent agreement between the SpeedUp model results and the test data. The model can be readily used for SuperLigtrademark ion exchange resins, once the experimental data are complete

Exchange bias mediated by interfacial nanoparticles (invited)

Energy Technology Data Exchange (ETDEWEB)

Berkowitz, A. E., E-mail: aberk@ucsd.edu [Department of Physics, University of California, San Diego, La Jolla, California 92093 (United States); Center for Magnetic Recording Research, University of California, California 92093 (United States); Sinha, S. K. [Department of Physics, University of California, San Diego, La Jolla, California 92093 (United States); Fullerton, E. E. [Center for Magnetic Recording Research, University of California, California 92093 (United States); Smith, D. J. [Department of Physics, Arizona State University, Tempe, Arizona 85287 (United States)

2015-05-07

The objective of this study on the iconic exchange-bias bilayer Permalloy/CoO has been to identify those elements of the interfacial microstructure and accompanying magnetic properties that are responsible for the exchange-bias and hysteretic properties of this bilayer. Both epitaxial and polycrystalline samples were examined. X-ray and neutron reflectometry established that there existed an interfacial region, of width ∼1 nm, whose magnetic properties differed from those of Py or CoO. A model was developed for the interfacial microstructure that predicts all the relevant properties of this system; namely; the temperature and Permalloy thickness dependence of the exchange-bias, H{sub EX}, and coercivity, H{sub C}; the much smaller measured values of H{sub EX} from what was nominally expected; the different behavior of H{sub EX} and H{sub C} in epitaxial and polycrystalline bilayers. A surprising result is that the exchange-bias does not involve direct exchange-coupling between Permalloy and CoO, but rather is mediated by CoFe{sub 2}O{sub 4} nanoparticles in the interfacial region.

Accurate Quantitation of Water-amide Proton Exchange Rates Using the Phase-Modulated CLEAN Chemical EXchange (CLEANEX-PM) Approach with a Fast-HSQC (FHSQC) Detection Scheme

International Nuclear Information System (INIS)

Hwang, Tsang-Lin; Zijl, Peter C.M. van; Mori, Susumu

1998-01-01

Measurement of exchange rates between water and NH protons by magnetization transfer methods is often complicated by artifacts, such as intramolecular NOEs, and/or TOCSY transfer from Cα protons coincident with the water frequency, or exchange-relayed NOEs from fast exchanging hydroxyl or amine protons. By applying the Phase-Modulated CLEAN chemical EXchange (CLEANEX-PM) spin-locking sequence, 135 o (x) 120 o (-x) 110 o (x) 110 o (-x) 120 o (x) 135 o (-x) during the mixing period, these artifacts can be eliminated, revealing an unambiguous water-NH exchange spectrum. In this paper, the CLEANEX-PM mixing scheme is combined with Fast-HSQC (FHSQC) detection and used to obtain accurate chemical exchange rates from the initial slope analysis for a sample of 15N labeled staphylococcal nuclease. The results are compared to rates obtained using Water EXchange filter (WEX) II-FHSQC, and spin-echo-filtered WEX II-FHSQC measurements, and clearly identify the spurious NOE contributions in the exchange system

Terms of trade and exchange rate regimes in developing countries

OpenAIRE

Christian Broda

2002-01-01

Since Friedman (1953), an advantage often attributed to flexible exchange rate regimes over fixed regimes is their ability to insulate more effectively the economy against real shocks. I use a post-Bretton Woods sample (1973-96) of seventy-five developing countries to assess whether the responses of real GDP, real exchange rates, and prices to terms-of-trade shocks differ systematically across exchange rate regimes. I find that responses are significantly different across regimes in a way tha...

Political Risk and Foreign Exchange Rates: an Efficient-Market Approach

OpenAIRE

Jean-Claude Cosset; Bruno Doutriaux de la Rianderie

1985-01-01

This paper examines the reaction of the foreign exchange market to the announcement of changes in the business environment of a country. Our results suggest that sampled political risk news conveys important information about a country's investment climate and causes its currency's exchange rate to vary. It appears, however, that the reaction of the foreign exchange market is more dramatic for unfavorable events than for favorable events. The evidence presented is also consisted with the hypo...

Simultaneous determination of platinum group elements and rhenium in rock samples using isotope dilution inductively coupled plasma mass spectrometry after cation exchange separation followed by solvent extraction

International Nuclear Information System (INIS)

Shinotsuka, Kazunori; Suzuki, Katsuhiko

2007-01-01

A simple and precise determination method for platinum group elements (PGEs) and Re in rock samples was developed using isotope dilution coupled with inductively coupled plasma mass spectrometry (ID-ICP-MS). Cation exchange separation was employed for simplicity, because it is applicable to group separation and simultaneous isotopic measurement in contrast with the widely used anion exchange separation which entails separate elution. However, its application to ID-ICP-MS has been limited due to spectral interferences from impurities retained in the PGE fraction even after ion chromatography. To overcome this limitation, solvent extraction using N-benzoyl-N-phenylhydroxylamine (BPHA) in chloroform was successfully applied for further purification. After the examination of optimum experimental parameters in cation exchange separation and solvent extraction using synthetic PGE solution, the established procedure was applied to the determination of PGEs and Re in some geochemical reference materials. The obtained results agreed well with the literature data determined using the different digestion methods (NiS fire assay and the use of a high-pressure asher) within the analytical uncertainties of each other. Significant difference in reproducibility between Ru, Ir, Pt and Os group, and Pd and Re group was observed in the results for BHVO-2 and JA-2. By considering the error factors affecting analytical reproducibility, we concluded that the difference is ascribed to the sample heterogeneity of minor minerals enriched in Ru, Ir, Pt and Os

A firm-specific exposure analyis of the exchange-rate exposure of Dutch firms

NARCIS (Netherlands)

de Jong, A.; Ligterink, J.; Macrae, V.

2006-01-01

We examine the relationship between exchange-rate changes and stock returns for a sample of Dutch firms over 1994-1998. We find that over 50 per cent of the firms are significantly exposed to exchange-rate risk. Furthermore, all firms with significant exchange-rate exposure benefit from a

Exchange-Mediated Contrast in CEST and Spin-Lock Imaging

Science.gov (United States)

Cobb, Jared Guthrie; Li, Ke; Xie, Jingping; Gochberg, Daniel F.; Gore, John C.

2014-01-01

PURPOSE Magnetic resonance images of biological media based on chemical exchange saturation transfer (CEST) show contrast that depends on chemical exchange between water and other protons. In addition, spin-lattice relaxation rates in the rotating frame (R1ρ) are also affected by exchange, especially at high fields, and can be exploited to provide novel, exchange-dependent contrast. Here, we evaluate and compare the factors that modulate the exchange contrast for these methods using simulations and experiments on simple, biologically relevant samples. METHODS Simulations and experimental measurements at 9.4T of rotating frame relaxation rate dispersion and CEST contrast were performed on solutions of macromolecules containing amide and hydroxyl exchanging protons. RESULTS The simulations and experimental measurements confirm that both CEST and R1ρ measurements depend on similar exchange parameters, but they manifest themselves differently in their effects on contrast. CEST contrast may be larger in the slow and intermediate exchange regimes for protons with large resonant frequency offsets (e.g. > 2ppm). Spin-locking techniques can produce larger contrast enhancement when resonant frequency offsets are small (exchange is in the intermediate to fast regime. The image contrasts scale differently with field strength, exchange rate and concentration. CONCLUSION CEST and R1ρ measurements provide different and somewhat complementary information about exchange in tissues. Whereas CEST can depict exchange of protons with specific chemical shifts, appropriate R1ρ dependent acquisitions can be employed to selectively portray protons of specific exchange rates. PMID:24239335

Exchange-mediated contrast in CEST and spin-lock imaging.

Science.gov (United States)

Cobb, Jared Guthrie; Li, Ke; Xie, Jingping; Gochberg, Daniel F; Gore, John C

2014-01-01

Magnetic resonance images of biological media based on chemical exchange saturation transfer (CEST) show contrast that depends on chemical exchange between water and other protons. In addition, spin-lattice relaxation rates in the rotating frame (R1ρ) are also affected by exchange, especially at high fields, and can be exploited to provide novel, exchange-dependent contrast. Here, we evaluate and compare the factors that modulate the exchange contrast for these methods using simulations and experiments on simple, biologically relevant samples. Simulations and experimental measurements at 9.4 T of rotating frame relaxation rate dispersion and CEST contrast were performed on solutions of macromolecules containing amide and hydroxyl exchanging protons. The simulations and experimental measurements confirm that both CEST and R1ρ measurements depend on similar exchange parameters, but they manifest themselves differently in their effects on contrast. CEST contrast may be larger in the slow and intermediate exchange regimes for protons with large resonant frequency offsets (e.g. >2 ppm). Spin-locking techniques can produce larger contrast enhancement when resonant frequency offsets are small (exchange is in the intermediate-to-fast regime. The image contrasts scale differently with field strength, exchange rate and concentration. CEST and R1ρ measurements provide different and somewhat complementary information about exchange in tissues. Whereas CEST can depict exchange of protons with specific chemical shifts, appropriate R1ρ-dependent acquisitions can be employed to selectively portray protons of specific exchange rates. © 2013.

Foreign exchange risk management : how are the largest non-financial companies in Norway managing their foreign exchange rate exposure?

OpenAIRE

Eriksen, Krister; Wedøe, Ola

2010-01-01

The purpose of this thesis is to investigate how the largest non-financial companies in Norway manage their foreign exchange rate exposure. This is investigated through the use of a survey distributed to a sample the largest non-financial firms in Norway. According to our results, the largest non-financial companies in Norway have a predefined strategy for managing foreign exchange risk, which is defined by the board of directors or by the management in the organisation. The companies’ mai...

Conformational sampling enhancement of replica exchange molecular dynamics simulations using swarm particle intelligence

International Nuclear Information System (INIS)

Kamberaj, Hiqmet

2015-01-01

In this paper, we present a new method based on swarm particle social intelligence for use in replica exchange molecular dynamics simulations. In this method, the replicas (representing the different system configurations) are allowed communicating with each other through the individual and social knowledge, in additional to considering them as a collection of real particles interacting through the Newtonian forces. The new method is based on the modification of the equations of motion in such way that the replicas are driven towards the global energy minimum. The method was tested for the Lennard-Jones clusters of N = 4,  5, and 6 atoms. Our results showed that the new method is more efficient than the conventional replica exchange method under the same practical conditions. In particular, the new method performed better on optimizing the distribution of the replicas among the thermostats with time and, in addition, ergodic convergence is observed to be faster. We also introduce a weighted histogram analysis method allowing analyzing the data from simulations by combining data from all of the replicas and rigorously removing the inserted bias

Isotopic exchange of nitrogen and ammonia synthesis on uranium nitride

International Nuclear Information System (INIS)

Panov, G.I.; Boreskov, G.K.; Kharitonov, A.S.; Moroz, Eh.M.; Sobolev, V.I.

1984-01-01

The catalytic properties of uranium nitride samples of different chemical composition: α - U 2 N 3 and UNsub(1, 70) are compared. The isotopic exchange at 553-623 K in both cases is realized by reversible dissociative nitrogen adsorption. Despite the proximity of structural and thermodynamic phase characteristics, the nitrogen adsorption heat differs by 120 kJ/mol which leads to strong differences in catalytic sample properties. It is shown that the isotopic exchange serves a reliable characteristic of activation of molecular nitrogen and its ability to react with the ammonia synthesis

Standard methods for sampling and sample preparation for gamma spectroscopy

International Nuclear Information System (INIS)

Taskaeva, M.; Taskaev, E.; Nikolov, P.

1993-01-01

The strategy for sampling and sample preparation is outlined: necessary number of samples; analysis and treatment of the results received; quantity of the analysed material according to the radionuclide concentrations and analytical methods; the minimal quantity and kind of the data needed for making final conclusions and decisions on the base of the results received. This strategy was tested in gamma spectroscopic analysis of radionuclide contamination of the region of Eleshnitsa Uranium Mines. The water samples was taken and stored according to the ASTM D 3370-82. The general sampling procedures were in conformity with the recommendations of ISO 5667. The radionuclides was concentrated by coprecipitation with iron hydroxide and ion exchange. The sampling of soil samples complied with the rules of ASTM C 998, and their sample preparation - with ASTM C 999. After preparation the samples were sealed hermetically and measured. (author)

Molecular exchange of n-hexane in zeolite sieves studied by diffusion-diffusion and T{sub 1}-diffusion nuclear magnetic resonance exchange spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Neudert, Oliver; Stapf, Siegfried; Mattea, Carlos, E-mail: carlos.mattea@tu-ilmenau.de [Fachgebiet Technische Physik II/Polymerphysik, Institute of Physics, Technische Universitaet Ilmenau, PO Box 100 565, 98684 Ilmenau (Germany)

2011-03-15

Molecular exchange properties and diffusion of n-hexane embedded in a bimodal pore structure with characteristic length scales in the order of nano and micrometres, respectively, formed by packing of zeolite particles, are studied. Two-dimensional (2D) nuclear magnetic resonance (NMR) diffusion correlation experiments together with relaxation-diffusion correlation experiments are performed at low magnetic field using a single-sided NMR scanner. The exchange time covers a range from 10{sup -3} to 10{sup -1} s. The molecular exchange properties are modulated by transport inside the zeolite particles. Different exchange regimes are observed for molecules starting from different positions inside the porous sample. The influence of the spin-lattice relaxation properties of the fluid molecules inside the zeolite particles on the signal intensity is also studied. A Monte Carlo simulation of the exchange process is performed and is used to support the analysis of the experimental data.

Oxygen isotope exchange with quartz during pyrolysis of silver sulfate and silver nitrate.

Science.gov (United States)

Schauer, Andrew J; Kunasek, Shelley A; Sofen, Eric D; Erbland, Joseph; Savarino, Joel; Johnson, Ben W; Amos, Helen M; Shaheen, Robina; Abaunza, Mariana; Jackson, Terri L; Thiemens, Mark H; Alexander, Becky

2012-09-30

Triple oxygen isotopes of sulfate and nitrate are useful metrics for the chemistry of their formation. Existing measurement methods, however, do not account for oxygen atom exchange with quartz during the thermal decomposition of sulfate. We present evidence for oxygen atom exchange, a simple modification to prevent exchange, and a correction for previous measurements. Silver sulfates and silver nitrates with excess (17)O were thermally decomposed in quartz and gold (for sulfate) and quartz and silver (for nitrate) sample containers to O(2) and byproducts in a modified Temperature Conversion/Elemental Analyzer (TC/EA). Helium carries O(2) through purification for isotope-ratio analysis of the three isotopes of oxygen in a Finnigan MAT253 isotope ratio mass spectrometer. The Δ(17)O results show clear oxygen atom exchange from non-zero (17)O-excess reference materials to zero (17)O-excess quartz cup sample containers. Quartz sample containers lower the Δ(17)O values of designer sulfate reference materials and USGS35 nitrate by 15% relative to gold or silver sample containers for quantities of 2-10 µmol O(2). Previous Δ(17)O measurements of sulfate that rely on pyrolysis in a quartz cup have been affected by oxygen exchange. These previous results can be corrected using a simple linear equation (Δ(17)O(gold) = Δ(17)O(quartz) * 1.14 + 0.06). Future pyrolysis of silver sulfate should be conducted in gold capsules or corrected to data obtained from gold capsules to avoid obtaining oxygen isotope exchange-affected data. Copyright © 2012 John Wiley & Sons, Ltd.

Distribution of Components in Ion Exchange Materials Taken from the K East Basin and Leaching of Ion Exchange Materials by Nitric/Hydrofluoric Acid and Nitric/Oxalic Acid

International Nuclear Information System (INIS)

Delegard, C.H.; Rinehart, D.E.; Hoopes, F.V.

1998-01-01

Laboratory tests were performed to examine the efficacy of mixed nitric/hydrofluoric acid followed by mixed nitric/oxalic acid leach treatments to decontaminate ion exchange materials that have been found in a number of samples retrieved from K East (KE)Basin sludge. The ion exchange materials contain organic ion exchange resins and zeolite inorganic ion exchange material. Based on process records, the ion exchange resins found in the K Basins is a mixed-bed, strong acid/strong base material marketed as Purolite NRW-037. The zeolite material is Zeolon-900, a granular material composed of the mineral mordenite. Radionuclides sorbed or associated with the ion exchange material can restrict its disposal to the Environmental Restoration Disposal Facility (ERDF). The need for testing to support development of a treatment process for K Basin sludge has been described in Section 4.2 of ''Testing Strategy to Support the Development of K Basins Sludge Treatment Process'' (Flament 1998). Elutriation and washing steps are designed to remove the organic resins from the K Basin sludge. To help understand the effects of the anticipated separation steps, tests were performed with well-rinsed ion exchange (IX) material from KE Basin floor sludge (sample H-08 BEAD G) and with well-rinsed IX having small quantities of added KE canister composite sludge (sample KECOMP). Tests also were performed to determine the relative quantities of organic and inorganic IX materials present in the H-08 K Basin sludge material. Based on chemical analyses of the separated fractions, the rinsed and dry IX material H-08 BEAD G was found to contain 36 weight percent inorganic material (primarily zeolite). The as-received (unrinsed) and dried H-08 material was estimated to contain 45 weight percent inorganic material

Optimization of determination of 126Sn by ion exchange chromatography method (presentation)

International Nuclear Information System (INIS)

Pasteka, L.; Dulanska, S.

2013-01-01

The aim of the work is to optimize the uptake of tin on anion exchange resins and application of this knowledge for the analysis of samples of radioactive waste from the device of Jaslovske Bohunice and Mochovce in determining of 126 Sn. First to be optimized a method for the separation of tin on ion exchange sorbent Anion Exchange Resin (1-X8, Chloride Form) from Eichrom Technologies. Model sample was prepared in 7 mol dm -3 HCl, because in that environment a sorbent effectively captures the tin, which is bounded complexly with chloride anions as SnCl 6 2- . The radiochemical separation yield was monitored by gamma spectrometric measurements on high purity germanium detector HPGe (E = 391 keV) by adding isotope 113 Sn to each model solution. The method of tin separation was optimized on model samples.

Feasibility of wavelength dispersive X-ray fluorescence spectrometry for a simplified analysis of bromine in water samples with the aid of a strong anion exchange disk

International Nuclear Information System (INIS)

An, Jinsung; Jung, Hyeyeon; Bae, Jo-Ri; Yoon, Hye-On; Seo, Jungju

2014-01-01

The feasibility of wavelength dispersive X-ray fluorescence spectrometry (WDXRF) for a simplified analysis of bromine (Br) in water samples with the aid of strong anion exchange (SAX) disk was assessed in this study. Dissolved Br in the water sample was pre-concentrated on the SAX disk and directly analyzed by WDXRF without an elution step. The SAX disk was capable of fully adsorbing both bromide (Br − ) and bromate (BrO 3 − ) on its surface owing to their anionic properties, regardless of the pH level of environmental samples. The SAX–WDXRF system was examined using calibration standards (i.e., SAX disks with specific amounts of Br retained; 1, 10, 50, 100 and 500 μg), and a determination coefficient of R 2 = 0.9999 was yielded. The system had a low detection limit for Br (limit of detection = 0.253 μg for Br on the SAX disk) with good reproducibility (relative standard error (RSE) = 4–7%). Spike and inter-comparison tests were performed to confirm the accuracy of the proposed SAX–WDXRF method. Both tests exhibited reasonable accuracy (RSE = 3–6%). The method is simple and easy, indicating a great possibility of application in various environmental sample types, especially for which a simplified analytical system for the determination of Br is urgently required. - Highlights: • Bromide and bromate were entirely retained on a strong anion exchange (SAX) disk. • The SAX disk was used to pre-concentrate dissolved Br species from water samples. • The SAX disk adsorbing dissolved Br was directly analyzed by WDXRF. • The accuracy of the SAX–WDXRF method was confirmed by spike and inter-comparison tests. • Rapid and sensitive Br analysis can be achieved using the proposed SAX–WDXRF method

Exchangeable fraction of elements in alluvial sediments under waste disposal site (Zagreb, Croatia)

International Nuclear Information System (INIS)

Vertacnik, A.; Barisic, D.; Musani, Lj.; Prohic, E.; Juracic, M.

1997-01-01

Concentrations of Ag, Ba, Cd, Ce, Cs, Co, Cr, Eu, Fe, Rb, Sc, Sr, Th, and Zn exchangeable fractions were determined in alluvial sediments at waste disposal site area in the vicinity of water-well field. Samples have been'leached with 0.5M NH 4 Cl at a sample/solution ratio of 1:20 during 24 hours without shaking. INAA of dry NH 4 Cl residues show that the concentrations of exchangeable elements determined in the most of the sediments below the wastes have natural levels. Ag, Ba and Sr are readily exchangeable; Rb, Cs and Zn have lower exchangeability, while Cd, Ce, Th, Sc, Eu, Cr, Fe and Co are rather immobile. Extremely high total and exchangeable silver concentration was found at 6.5-6.8 meters below waste in the aerated layer occasionally under the water table. Exchangeable concentrations in deeper water-bearing sediment layers are not elevated. Due to this, one can presume that the upper sediment layers act as chemical filter generally preventing the infiltration from overlying wastes into water-bearing layers. (author)

Segmented heat exchanger

Science.gov (United States)

Baldwin, Darryl Dean; Willi, Martin Leo; Fiveland, Scott Byron; Timmons, Kristine Ann

2010-12-14

A segmented heat exchanger system for transferring heat energy from an exhaust fluid to a working fluid. The heat exchanger system may include a first heat exchanger for receiving incoming working fluid and the exhaust fluid. The working fluid and exhaust fluid may travel through at least a portion of the first heat exchanger in a parallel flow configuration. In addition, the heat exchanger system may include a second heat exchanger for receiving working fluid from the first heat exchanger and exhaust fluid from a third heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the second heat exchanger in a counter flow configuration. Furthermore, the heat exchanger system may include a third heat exchanger for receiving working fluid from the second heat exchanger and exhaust fluid from the first heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the third heat exchanger in a parallel flow configuration.

Production of artifact methylmercury during the analysis of certified reference sediments: Use of ionic exchange in the sample treatment step to minimise the problem

International Nuclear Information System (INIS)

Delgado, Alejandra; Prieto, Ailette; Zuloaga, Olatz; Diego, Alberto de; Madariaga, Juan Manuel

2007-01-01

Production of artifact methylmercury (MeHg + ) during the analysis of two certified reference sediments, CRM-580 and IAEA-405, was investigated. Leaching of the analyte from the solid sample was achieved by ultrasound assisted acidic extraction. The aqueous leachate was either ethylated (NaBEt 4 ) or phenylated (NaBPh 4 ) using acetic/acetate or citric/citrate to buffer the solution. Preconcentration of the volatile compounds was carried out by extraction with an organic solvent (n-hexane) or solid phase microextraction (SPME). MeHg + was finally separated and detected by gas chromatography with atomic emission or mass spectrometry detection (GC-MIP-AED or GC-MS). In all the cases the concentrations obtained for MeHg + in the CRM-580 were significantly higher than the certified value. For the IAEA-405, however, the MeHg + concentration found was always statistically indistinguishable from the certified value. Experiments were also conducted with synthetic samples, such as aqueous mixtures of MeHg + and inorganic mercury (Hg 2+ ) or silica-gel spiked with both compounds. The methylation rates found (defined as the percentage of Hg 2+ present in the sample which methylates to give artifact MeHg + ) ranged from not observable (in certain synthetic aqueous mixtures) to 0.57% (analysis of CRM-580 under certain conditions). As the amount of Hg 2+ available in the sample seems to be the main factor controlling the magnitude of the artifact, several experiments were conducted using an ionic exchange resin (Dowex M-41) in order to minimise the concentration of this chemical in the reaction medium. First, a hydrochloric leachate of the sample was passed through a microcolumn packed with the exchanger. Second, the resin was mixed with the sample prior to extraction with HCl. In both cases, the predominant Hg 2+ species, HgCl 4 2- , was adsorbed on the resin, whereas MeHg + , mainly as MeHgCl, remained in solution. Following the second option, a new method to analyse MeHg + in

Exchange rate rebounds after foreign exchange market interventions

Science.gov (United States)

Hoshikawa, Takeshi

2017-03-01

This study examined the rebounds in the exchange rate after foreign exchange intervention. When intervention is strongly effective, the exchange rate rebounds at next day. The effect of intervention is reduced slightly by the rebound after the intervention. The exchange rate might have been 67.12-77.47 yen to a US dollar without yen-selling/dollar-purchasing intervention of 74,691,100 million yen implemented by the Japanese government since 1991, in comparison to the actual exchange rate was 103.19 yen to the US dollar at the end of March 2014.

Ion exchange filter transition plan for BWRs and PWRs

International Nuclear Information System (INIS)

Garcia, Susan; McElrath, Joel; Varnam, Jeremie; Giannelli, Joseph F.

2014-01-01

Analysis and quantification of reactor water, feedwater, and chemical and volume control system (CVCS) soluble metals and radioisotopes are essential for monitoring species that impact fuel performance, steam generator and heat exchanger performance, mitigation of stress corrosion cracking of reactor piping and internals, radiation fields and ensuring that dose mitigation techniques are effective. Soluble species in the CVCS, feedwater, reactor water and other process sample streams are usually collected on ion exchange membranes after the sample has passed through a 0.45 or 0.1 μm membrane filter. Cationic species are predominantly of interest. Most nuclear plants currently use cation exchange membranes from Toray Industries, Inc. In September 2012, it was reported that Toray Industries, Inc. would discontinue the manufacturing of cation exchange membranes at the end of 2012. Similar reports were received concerning ion exchange membranes manufactured by Pall Corporation. These reports prompted several plants and utilities to begin evaluating other products from various vendors to replace their current ion exchange membranes in preparation for a transition. With this possible change having a potential impact on the water chemistry analyses that are important for monitoring fuel reliability and corrosion and dose control, an initial scoping evaluation of ion exchange membrane availability from various vendor and plant experiences was conducted. Recommended approaches were provided to close identified gaps and reduce burden on nuclear plant chemistry laboratories. Additional work required in 2014, includes an independent laboratory review of membrane performance and in-plant demonstrations. These demonstrations and evaluations will assist the industry by providing the technical input needed to manage a change in membrane use so that preferred processes and media can be identified to minimize any adverse impacts on chemistry analyses that support chemistry control

Evaluation of kinetic phosphorescence analysis for the determination of uranium

International Nuclear Information System (INIS)

Croatto, P.V.; Frank, I.W.; Johnson, K.D.; Mason, P.B.; Smith, M.M.

1997-12-01

In the past, New Brunswick Laboratory (NBL) has used a fluorometric method for the determination of sub-microgram quantities of uranium. In its continuing effort to upgrade and improve measurement technology, NBL has evaluated the commercially-available KPA-11 kinetic phosphorescence analyzer (Chemchek, Richland, WA). The Chemchek KPA-11 is a bench-top instrument which performs single-measurement, quench-corrected analyses for trace uranium. It incorporates patented kinetic phosphorimetry techniques to measure and analyze sample phosphorescence as a function of time. With laser excitation and time-corrected photon counting, the KPA-11 has a lower detection limit than conventional fluorometric methods. Operated with a personal computer, the state-of-the-art KPA-11 offers extensive time resolution and phosphorescence lifetime capabilities for additional specificity. Interferences are thereby avoided while obtaining precise measurements. Routine analyses can be easily and effectively accomplished, with the accuracy and precision equivalent to the pulsed-laser fluorometric method presently performed at NBL, without the need for internal standards. Applications of kinetic phosphorimetry at NBL include the measurement of trace level uranium in retention tank, waste samples, and low-level samples. It has also been used to support other experimental activities at NBL by the measuring of nanogram amounts of uranium contamination (in blanks) in isotopic sample preparations, and the determining of elution curves of different ion exchange resins used for uranium purification. In many cases, no pretreatment of samples was necessary except to fume them with nitric acid, and then to redissolve and dilute them to an appropriate concentration with 1 M HNO 3 before measurement. Concentrations were determined on a mass basis (microg U/g of solution), but no density corrections were needed since all the samples (including the samples used for calibration) were in the same density

Time-varying exchange rate pass-through: experiences of some industrial countries

OpenAIRE

Toshitaka Sekine

2006-01-01

This paper estimates exchange rate pass-through of six major industrial countries using a time-varying parameter with stochastic volatility model. Exchange rate pass-through is divided into impacts of exchange rate fluctuations to import prices (first-stage pass-through) and those of import price movements to consumer prices (second-stage pass-through). The paper finds that both stages of pass-through have declined over time for all the sample countries. The decline in second-stage pass-throu...

Out-of-sample Forecasting Performance of Won/Dollar Exchange Rate Return Volatility Model

Directory of Open Access Journals (Sweden)

Hojin Lee

2009-06-01

Full Text Available We compare the out-of-sample forecasting performance of volatility models using daily exchange rate for the KRW/USD during the period from 1992 to 2008. For various forecasting horizons, historical volatility models with a long memory tend to make more accurate forecasts. Especially, we carefully observe the difference between the EWMA and the GARCH(1,1 model. Our empirical finding that the GARCH model puts too much weight on recent observations relative to those in the past is consistent with prior evidence showing that asset market volatility has a long memory, such as Ding and Granger (1996. The forecasting model with the lowest MSFE and VaR forecast error among the models we consider is the EWMA model in which the forecast volatility for the coming period is a weighted average of recent squared return with exponentially declining weights. In terms of forecast accuracy, it clearly dominates the widely accepted GARCH and rolling window GARCH models. We also present a multiple comparison of the out-of-sample forecasting performance of volatility using the stationary bootstrap of Politis and Romano (1994. We find that the White's reality check for the GARCH(1,1 expanding window model and the FIGARCH(1,1 expanding window model clearly reject the null hypothesis and there exists a better model than the two benchmark models. On the other hand, when the EWMA model is the benchmark, the White's for all forecasting horizons are very high, which indicates the null hypothesis may not be rejected. The Hansen's report the same results. The GARCH(1,1 expanding window model and the FIGARCH(1,1 expanding window model are dominated by the best competing model in most of the forecasting horizons. In contrast, the RiskMetrics model seems to be the most preferred. We also consider combining the forecasts generated by averaging the six raw forecasts and a trimmed set of forecasts which calculate the mean of the four forecasts after disregarding the highest and

Sulfur geochemistry of hydrothermal waters in Yellowstone National Park, Wyoming, USA. III. An anion-exchange resin technique for sampling and preservation of sulfoxyanions in natural waters

Directory of Open Access Journals (Sweden)

Ball James W

2003-06-01

Full Text Available A sampling protocol for the retention, extraction, and analysis of sulfoxyanions in hydrothermal waters has been developed in the laboratory and tested at Yellowstone National Park and Green Lake, NY. Initial laboratory testing of the anion-exchange resin Bio-Rad™ AG1-X8 indicated that the resin was well suited for the sampling, preservation, and extraction of sulfate and thiosulfate. Synthetic solutions containing sulfate and thiosulfate were passed through AG1-X8 resin columns and eluted with 1 and 3 M KCl, respectively. Recovery ranged from 89 to 100%. Comparison of results for water samples collected from five pools in Yellowstone National Park between on-site IC analysis (U.S. Geological Survey mobile lab and IC analysis of resin-stored sample at SUNY-Stony Brook indicates 96 to 100% agreement for three pools (Cinder, Cistern, and an unnamed pool near Cistern and 76 and 63% agreement for two pools (Sulfur Dust and Frying Pan. Attempts to extract polythionates from the AG1-X8 resin were made using HCl solutions, but were unsuccessful. Bio-Rad™ AG2-X8, an anion-exchange resin with weaker binding sites than the AG1-X8 resin, is better suited for polythionate extraction. Sulfate and thiosulfate extraction with this resin has been accomplished with KCl solutions of 0.1 and 0.5 M, respectively. Trithionate and tetrathionate can be extracted with 4 M KCl. Higher polythionates can be extracted with 9 M hydrochloric acid. Polythionate concentrations can then be determined directly using ion chromatographic methods, and laboratory results indicate recovery of up to 90% for synthetic polythionate solutions using AG2-X8 resin columns.

Tensor exchange amplitudes in K +- N charge exchange reactions

International Nuclear Information System (INIS)

Svec, M.

1979-01-01

Tensor (A 2 ) exchange amplitudes in K +- N charge exchange (CEX) are constructed from the K +- N CEX data supplemented by information on the vector (rho) exchange amplitudes from πN sca tering. We observed new features in the t-structure of A 2 exchange amplitudes which contradict the t-de pendence anticipated by most of the Regge models. The results also provide evidence for violation of weak exchange degeneracy

Isolation of radioactive strontium from natural samples. Separation of strontium from alkaline and alkaline earth elements by means of mixed solvent anion exchange

International Nuclear Information System (INIS)

Grahek, Z.; Kosutic, K.; Lulic, S.; Kvastek, K.; Eskinja, I.

1999-01-01

This paper presents the results of studies which led to the procedures for the chromatographic separation of radioactive strontium from alkaline, earth-alkaline and other elements in natural samples, on columns filled with strong base anion exchangers using alcoholic solutions of nitric acid as eluents. It has been shown that potassium, caesium, calcium, barium, yttrium and strontium can be adsorbed on strong base anion exchangers of the Dowex and Amberlite type, which contain the quaternary ammonium group with nitrate as counter-ion, from solutions of nitric acid in alcohol. Adsorption strength increases in the order methanol 3 in methanol, while they are adsorbed from ethanol and propanol. The adsorption strength is influenced by the polarity of alcohol, by the concentration of nitrate and by pH. The strength with which strontium adsorbs on the exchangers increases in the interval from 0 to 0.25M NH 4 NO 3 in methanol, after which it starts to decrease. Strontium adsorbs to the exchangers from the alcoholic solution of ammonium nitrate twice as strongly as from the alcoholic solution of nitric acid, while a fraction of water in pure alcohol exceeding 10% prevents adsorption. In the mixture of alcohol and nitric acid, the adsorption strength for calcium and strontium increases with the increase of the volume fraction of alcohol with a lower dielectric constant. The rate and strength of adsorption of ions on the exchanger also increase in the series 0.25M HNO 3 in methanol 3 in ethanol 3 in 1-propanol for each individual ion, as well as in the Ca 3 in methanol, 0.25M HNO 3 in ethanol and 0.25M HNO 3 in propanol. Separation is also possible from alcohol mixtures. Strontium separation is most difficult from calcium, while the efficiency of separation increases with a decrease of the polarity of the used alcohol or alcohol mixture. The first group elements of the periodic table are not separated from each other in this way, while the elements of the second group are

The Effects of Workers’ Remittances on Exchange Rate Volatility and Exports Dynamics -New Evidence from Pakistan

Directory of Open Access Journals (Sweden)

Adnan Khurshid

2017-03-01

Full Text Available This study examines the impact of remittances on the exchange rate and exports in Pakistan, using the system GMM aproach on annual data series. We carry out a full sample Granger causality test along with the sub-sample rolling window approach using monthly data series to find the causal relationship between remittances (REM and the exchange rate (EXR. The System GMM results reveal that remittances depreciate the exchange rate and have a positive influence on export competitiveness. In addition to this, the remittance inflow appreciates the exchange rate only if it is used for savings and negatively affects competitiveness if it is channeled towards consumption. The change in exchange rate regime from multiple to flexible depreciated the exchange rate while, the global financial crises uplifted the currency rate and negatively affect the exports. The results show the bidirectional causal relationship between remittances and the exchange rate. The outcomes further reveal that the parameters in the VAR model are unstable, which is a clear indication of the presence of structural changes. The rolling window estimation approach with time-varying characteristics finds bi-directional causality between REM and the EXR in the different sub-samples. The results of this study fall in line with the portfolio model proposed by Mussa (1984 which states that the flow of remittances causes appreciation. The sub-sample causality is related to significant economic events, which means the results are not a statistical artifact.

Pu Anion Exchange Process Intensification

International Nuclear Information System (INIS)

Taylor-Pashow, Kathryn M. L.

2017-01-01

This research is focused on improving the efficiency of the anion exchange process for purifying plutonium. While initially focused on plutonium, the technology could also be applied to other ion-exchange processes. Work in FY17 focused on the improvement and optimization of porous foam columns that were initially developed in FY16. These foam columns were surface functionalized with poly(4-vinylpyridine) (PVP) to provide the Pu specific anion-exchange sites. Two different polymerization methods were explored for maximizing the surface functionalization with the PVP. The open-celled polymeric foams have large open pores and large surface areas available for sorption. The fluid passes through the large open pores of this material, allowing convection to be the dominant mechanism by which mass transport takes place. These materials generally have very low densities, open-celled structures with high cell interconnectivity, small cell sizes, uniform cell size distributions, and high structural integrity. These porous foam columns provide advantages over the typical porous resin beads by eliminating the slow diffusion through resin beads, making the anion-exchange sites easily accessible on the foam surfaces. The best performing samples exceeded the Pu capacity of the commercially available resin, and also offered the advantage of sharper elution profiles, resulting in a more concentrated product, with less loss of material to the dilute heads and tails cuts. An alternate approach to improving the efficiency of this process was also explored through the development of a microchannel array system for performing the anion exchange.

Pu Anion Exchange Process Intensification

Energy Technology Data Exchange (ETDEWEB)

Taylor-Pashow, Kathryn M. L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2017-10-06

This research is focused on improving the efficiency of the anion exchange process for purifying plutonium. While initially focused on plutonium, the technology could also be applied to other ion-exchange processes. Work in FY17 focused on the improvement and optimization of porous foam columns that were initially developed in FY16. These foam columns were surface functionalized with poly(4-vinylpyridine) (PVP) to provide the Pu specific anion-exchange sites. Two different polymerization methods were explored for maximizing the surface functionalization with the PVP. The open-celled polymeric foams have large open pores and large surface areas available for sorption. The fluid passes through the large open pores of this material, allowing convection to be the dominant mechanism by which mass transport takes place. These materials generally have very low densities, open-celled structures with high cell interconnectivity, small cell sizes, uniform cell size distributions, and high structural integrity. These porous foam columns provide advantages over the typical porous resin beads by eliminating the slow diffusion through resin beads, making the anion-exchange sites easily accessible on the foam surfaces. The best performing samples exceeded the Pu capacity of the commercially available resin, and also offered the advantage of sharper elution profiles, resulting in a more concentrated product, with less loss of material to the dilute heads and tails cuts. An alternate approach to improving the efficiency of this process was also explored through the development of a microchannel array system for performing the anion exchange.

Photomultiplier protector for a fluorometer

International Nuclear Information System (INIS)

Priarone, P.; St John, P.A.

1982-01-01

The photometer is adapted for sensing radiation emitted by a chemical sample held in a cuvette received in a first compartment and includes a highly sensitive photomultiplier in a second compartment adjacent the first compartment for detecting fluorescent radiation emitted by the chemical sample and passing through an opening between the compartments. A mechanical protector assembly is provided for protecting the photomultiplier from ambient light and includes a movable light shield movable between a first position blocking the opening and a second position not blocking the opening. A knob is provided for moving the light shield to the first position to protect the photomultiplier from light entering from the first compartment when the first compartment is opened for insertion or removal of a cuvette, and for moving the light shield to the second position not blocking the opening to permit radiation emitted by the chemical sample to impinge upon the photomultiplier in the second compartment. The photometer also includes a mechanical interlocking assembly for ensuring that the first compartment cannot be opened unless the light shield is in the first position to prevent ambient light from entering the second compartment from the first compartment and reaching the photomultiplier

Exchange functional by a range-separated exchange hole

International Nuclear Information System (INIS)

Toyoda, Masayuki; Ozaki, Taisuke

2011-01-01

An approximation to the exchange-hole density is proposed for the evaluation of the exact exchange energy in electronic structure calculations within the density-functional theory and the Kohn-Sham scheme. Based on the localized nature of density matrix, the exchange hole is divided into the short-range (SR) and long-range (LR) parts by using an adequate filter function, where the LR part is deduced by matching of moments with the exactly calculated SR counterpart, ensuring the correct asymptotic -1/r behavior of the exchange potential. With this division, the time-consuming integration is truncated at a certain interaction range, largely reducing the computation cost. The total energies, exchange energies, exchange potentials, and eigenvalues of the highest-occupied orbitals are calculated for the noble-gas atoms. The close agreement of the results with the exact values suggests the validity of the approximation.

A panel data investigation of real exchange rate misalignment and growth

Directory of Open Access Journals (Sweden)

Flávio Vilela Vieira

2012-09-01

Full Text Available The paper investigates the role of real exchange rate misalignment on long-run growth for a set of ninety countries using time series data from 1980 to 2004. We first estimate a panel data model (fixed and random effects for the real exchange rate in order to produce estimates of the equilibrium real exchange rate and this is then used to construct measures of real exchange rate misalignment. We provide an alternative set of estimates of RER misalignment using panel cointegration methods. The results for the two-step System GMM panel growth models indicate that the coefficients for real exchange rate misalignment are positive for different model specification and samples, which means that a more depreciated (appreciated real exchange rate helps (harms long-run growth. The estimated coefficients are higher for developing and emerging countries.

CYLINDER OF THE DISPOSABLE MASS EXCHANGE DEVICE FOR HEMOSORPTION

Directory of Open Access Journals (Sweden)

F. I. Kazakov

2015-01-01

Full Text Available BACKGROUND. Hemocarboperfusion, previously widely used in our country, can universally pass out of use due to the lack of industrial production of disposable mass exchange devices.MATERIAl AND METHODS. Physicochemical properties of materials and design features of the body samples elements of various sizes have been studied.RESULTS. The elements and materials properties of the hemosorption mass exchanger cylinder have been studied. Hydrodynamic parameters of manipulation using the developed cylinders at different perfusion rates have been studied in bench experiments.CONCLUSION. The original cylinder of the disposable mass exchange device for hemosorption, which meets the current clinical needs, has been developed. 

Oil prices and the rise and fall of the U.S. real exchange rate

International Nuclear Information System (INIS)

Amano, R.A.; Norden, S. van.

1993-12-01

It is examined whether a link exists between oil price shocks and the U.S. real effective exchange rate. Data used for the study are described and their time series properties and the long-run explanatory power of oil prices for the real exchange rate are examined. Apparent causal relationships between exchange rates and oil prices are examined. An unrestricted error correction model is reduced until an error correction model with reasonable properties is derived. Results show that the two variables appear to be cointegrated and that causality runs from oil prices to the exchange rate and not vice-versa. The single equation error correction model linking these two variables is stable and captures much of the in- and out-of-sample movement in the exchange rate in dynamic simulation. Tests are presented to show that the error correction model has significant post-sample predictive ability for both the size and sign of changes in the real effective exchange rate. The results suggest that oil prices may have been the dominant source of persistant real exchange rate shocks over the post-Bretton Woods period and that energy prices may have important implications for future work on exchange rate behaviour. 61 refs., 3 figs., 7 tabs

Treatment of radioactive ionic exchange resins by super- and sub-critical water oxidation (SCWO)

International Nuclear Information System (INIS)

Kim, Kyeongsook; Son, Soon Hwan; Kim, Kwang Sin; Han, Joo Hee; Han, Kee Do; Do, Seung Hoe

2010-01-01

As the usage of ion exchange resins increases the inventory of spent ion exchange resins increases in nuclear power plants. This study is to find an environmental-friendly process to treat theses spent resins. The test samples were prepared by diluting the slurry made by wet ball milling the spent cationic exchange resins for 24 h. The spent cationic exchange resins were separated from mixed ion exchange resins by a fluidized bed gravimetric separator. The decomposition of the samples was investigated with super-critical water oxidation (SCWO) equipment. A statistical test method - the central composite design as a statistical design of experiments - was adopted to find the optimum condition to decompose the spent exchange resins. The optimum condition was 60% of excess oxygen, 22.5 min of residence time, 0.615 wt% of NaOH, 358 of reaction temperature, and 3600 psi of reaction pressure, which is a sub-critical condition. The liquid product of the decomposition has the characteristics of 80-185 ppm of COD (Chemical Oxygen Demand), 4.0-6.0 of pH, and <1.0 ppm of corrosive components (Ni, Fe, Cr, and Mo). The exhaust gas from the SCWO equipment contained NOx of 0 ppm, SOx of 3 ppm (environment exhaust standard in Korea: NOx 200 ppm, SOx 300 ppm). Co-substituted mock samples were prepared to simulate spent cationic exchange resins from nuclear power plants which can contain radioactive Co isotopes. The conditions to obtain organic compound destruction ratio which conforms the effluent stand for the mock samples were found. The treated water filtered with 0.2-filter contained less than 1 ppm of Co. Thus Co recovery rate of more 99% was achieved.

Automated exchange transfusion and exchange rate.

Science.gov (United States)

Funato, M; Shimada, S; Tamai, H; Taki, H; Yoshioka, Y

1989-10-01

An automated blood exchange transfusion (BET) with a two-site technique has been devised by Goldmann et al and by us, using an infusion pump. With this method, we successfully performed exchange transfusions 189 times in the past four years on 110 infants with birth weights ranging from 530 g to 4,000 g. The exchange rate by the automated method was compared with the rate by Diamond's method. Serum bilirubin (SB) levels before and after BET and the maximal SB rebound within 24 hours after BET were: 21.6 +/- 2.4, 11.5 +/- 2.2, and 15.0 +/- 1.5 mg/dl in the automated method, and 22.0 +/- 2.9, 11.2 +/- 2.5, and 17.7 +/- 3.2 mg/dl in Diamond's method, respectively. The result showed that the maximal rebound of the SB level within 24 hours after BET was significantly lower in the automated method than in Diamond's method (p less than 0.01), though SB levels before and after BET were not significantly different between the two methods. The exchange rate was also measured by means of staining the fetal red cells (F cells) both in the automated method and in Diamond's method, and comparing them. The exchange rate of F cells in Diamond's method went down along the theoretical exchange curve proposed by Diamond, while the rate in the automated method was significantly better than in Diamond's, especially in the early stage of BET (p less than 0.01). We believe that the use of this automated method may give better results than Diamond's method in the rate of exchange, because this method is performed with a two-site technique using a peripheral artery and vein.

Leaching studies on ion exchange resins immobilized in bitumen matrix

International Nuclear Information System (INIS)

Grosche Filho, C.E.; Chandra, U.; Villalobos, J.P.

1986-01-01

Many samples of bitumen mixed with ion exchange resin labelled with 134 Cs were prepared to study radionuclide leaching from bitumen waste forms. The resins used in tests were nuclear grade mixed cationic/aniocic bead resins. Different bitumen types were assayed: two distilled and two oxidized bitumens. Leached fractions were collected accordingly to the recommendation of ISO method, with complete exchange of leachant after each sampling. The volume collected for analysis was one liter. Marinelli beckers were used to improve counting efficiency in a Ge(Li) detector. The diffusion coefficients for samples prepared with distilled and oxidized bitumens were obtained. Mathematical models of transport phenomena applied to cylindrical geometry was employed to fit experimental data aiming to explain leaching mechanism and predict the long time behavior of immobilized radionuclides. (M.C.K.) [pt

Scandium sorption by immobilized microdispersed forms of phosporus-containing ion exchangers

International Nuclear Information System (INIS)

Sokolova, Yu.V.; Kurdyumov, G.M.; Smirnov, A.V.; Mezhirov, M.S.

1991-01-01

The possibility to improve considerably kinetics of scandium sorption by phosphate ion exchangers, immobilized into polyacrylonitrile (PAN) fibers, as compared with granular samples of ion exchangers, was shown. The influence of dispersion degree of immobilized ionite particles on sorption rate was studied. It is ascertained that the ionite grinding to the particle size ≤ 52 μm is sufficient for the rate increase by 1-1.5 orders. A lower swelling of the immobilized ion exchanger is its additional advantage as compared with granular form

Heat exchanger

International Nuclear Information System (INIS)

Dostatni, A.W.; Dostatni, Michel.

1976-01-01

In the main patent, a description was given of a heat exchanger with an exchange surface in preformed sheet metal designed for the high pressure and temperature service particularly encountered in nuclear pressurized water reactors and which is characterised by the fact that it is composed of at least one exchanger bundle sealed in a containment, the said bundle or bundles being composed of numerous juxtaposed individual compartments whose exchange faces are built of preformed sheet metal. The present addendun certificate concerns shapes of bundles and their positioning methods in the exchanger containment enabling its compactness to be increased [fr

Quantitative chemical exchange saturation transfer with hyperpolarized nuclei (qHyper-CEST): sensing xenon-host exchange dynamics and binding affinities by NMR.

Science.gov (United States)

Kunth, M; Witte, C; Schröder, L

2014-11-21

The reversible binding of xenon to host molecules has found numerous applications in nuclear magnetic resonance studies. Quantitative characterization of the Xe exchange dynamics is important to understand and optimize the physico-chemical behavior of such Xe hosts, but is often challenging to achieve at low host concentrations. We have investigated a sensitive quantification technique based on chemical exchange saturation transfer with hyperpolarized nuclei, qHyper-CEST. Using simulated signals we demonstrated that qHyper-CEST yielded accurate and precise results and was robust in the presence of large amounts of noise (10%). This is of particular importance for samples with completely unknown exchange rates. Using these findings we experimentally determined the following exchange parameters for the Xe host cryptophane-A monoacid in dimethyl sulfoxide in one type of experiment: the ratio of bound and free Xe, the Xe exchange rate, the resonance frequencies of free and bound Xe, the Xe host occupancy, and the Xe binding constant. Taken together, qHyper-CEST facilitates sensitive quantification of the Xe exchange dynamics and binding to hydrophobic cavities and has the potential to analyze many different host systems or binding sites. This makes qHyper-CEST an indispensable tool for the efficient design of highly specific biosensors.

Tidal exchange of larvae of Sesarma catenata (Decapoda, Brachyura)

African Journals Online (AJOL)

The tidal exchange of larvae of the salt-marsh grapsid crab Sesarma catenata was studied in the Swartkops estuary, a tidally driven, shallow estuary in Algoa Bay, South Africa. Plankton samples were collected bimonlhly during spring and neap tides from October to March at the tidal inlet. Samples were collected hourly for ...

Determination of traces of phosphorus using isotope exchange

International Nuclear Information System (INIS)

Zeman, A.; Kratzer, K.

1976-01-01

A simple and selective radioanalytical method for the determination of phosphorus (0.015 - 5 μg in a 5 ml sample), based on the heterogeneous isotope exchange, has been developed. The sample containing phosphorus is shaken in the presence of molybdate with a standard solution of tetraphenylarsonium molybdophosphate labelled with phosphorus-32 in 1-2 dicloroethan. From the distribution of the activity between the aqueous and organic phases the amount of phosphorus in the sample can be determined. (Authors)

Sulfur geochemistry of hydrothermal waters in Yellowstone National Park, Wyoming, USA. III. An anion-exchange resin technique for sampling and preservation of sulfoxyanions in natural waters

Science.gov (United States)

Druschel, G.K.; Schoonen, M.A.A.; Nordstorm, D.K.; Ball, J.W.; Xu, Y.; Cohn, C.A.

2003-01-01

A sampling protocol for the retention, extraction, and analysis of sulfoxyanions in hydrothermal waters has been developed in the laboratory and tested at Yellowstone National Park and Green Lake, NY. Initial laboratory testing of the anion-exchange resin Bio-Rad??? AG1-X8 indicated that the resin was well suited for the sampling, preservation, and extraction of sulfate and thiosulfate. Synthetic solutions containing sulfate and thiosulfate were passed through AG1-X8 resin columns and eluted with 1 and 3 M KCl, respectively. Recovery ranged from 89 to 100%. Comparison of results for water samples collected from five pools in Yellowstone National Park between on-site IC analysis (U.S. Geological Survey mobile lab) and IC analysis of resin-stored sample at SUNY-Stony Brook indicates 96 to 100% agreement for three pools (Cinder, Cistern, and an unnamed pool near Cistern) and 76 and 63% agreement for two pools (Sulfur Dust and Frying Pan). Attempts to extract polythionates from the AG1-X8 resin were made using HCl solutions, but were unsuccessful. Bio-Rad??? AG2-X8, an anion-exchange resin with weaker binding sites than the AG1-X8 resin, is better suited for polythionate extraction. Sulfate and thiosulfate extraction with this resin has been accomplished with KCl solutions of 0.1 and 0.5 M, respectively. Trithionate and tetrathionate can be extracted with 4 M KCl. Higher polythionates can be extracted with 9 M hydrochloric acid. Polythionate concentrations can then be determined directly using ion chromatographic methods, and laboratory results indicate recovery of up to 90% for synthetic polythionate solutions using AG2-X8 resin columns. ?? The Royal Society of Chemistry and the Division of Geochemistry of the American Chemical Society 2003.

Exchangeable hydrogen explains the pH of spodosol Oa horizons

Science.gov (United States)

Ross, D.S.; David, M.B.; Lawrence, G.B.; Bartlett, R.J.

1996-01-01

The chemistry of extremely acid Oa horizons does not conform to traditional pH, Al, and base saturation relationships. Results from two separate studies of northeastern U.S. forested soils were used to investigate relationships between pH in water or dilute salt solutions and other soil characteristics. In Oa horizons with pH below 4, soil pH in dilute CaCl2 solution was correlated with exchangeable H+ measured either by titration (r = -0.88, P = 0.0001, n = 142) or by electrode (r = -0.89, P = 0.0001, n = 45). Exchangeable H+ expressed as a percentage of the cation-exchange capacity (CEC) was linear with pH and showed similar slopes for data from both studies. For all samples, pHw = 4.21 - 1.80 x H+/CEC (R2 = 0.69, n = 194). The reciprocal of the H+/CEC ratio is base saturation with Al added to the bases. Because of the low pH, exchangeable Al does not appear to behave as an acid. Exchangeable H+ remains an operationally defined quantity because of the difficulty in separating exchange and hydrolysis reactions. In a variety of neutral-salt extractants, concentration of H+ were correlated with 0.1 M BaCl2-exchangeable H+ (r > 0.91, P = 0.0001, n = 26) regardless of the strength of the extract. Nine successive extractions with 0.33 mM CaCl2 removed more H+ than was removed by single batch extractions with either 1 M KCl or 0.1 M BaCl2 (average H+ of 70, 43, and 49 mmol kg-1, respectively for 26 samples). The data showed little difference in the chemical behavior of Oa horizons from a variety of geographical sites and vegetation types.

Production of artifact methylmercury during the analysis of certified reference sediments: Use of ionic exchange in the sample treatment step to minimise the problem

Energy Technology Data Exchange (ETDEWEB)

Delgado, Alejandra [Kimika Analitikoa Saila, Euskal Herriko Unibertsitatea, 644 P.K., E-48080 Bilbao (Spain); Prieto, Ailette [Kimika Analitikoa Saila, Euskal Herriko Unibertsitatea, 644 P.K., E-48080 Bilbao (Spain); Zuloaga, Olatz [Kimika Analitikoa Saila, Euskal Herriko Unibertsitatea, 644 P.K., E-48080 Bilbao (Spain); Diego, Alberto de [Kimika Analitikoa Saila, Euskal Herriko Unibertsitatea, 644 P.K., E-48080 Bilbao (Spain)]. E-mail: alberto.dediego@ehu.es; Madariaga, Juan Manuel [Kimika Analitikoa Saila, Euskal Herriko Unibertsitatea, 644 P.K., E-48080 Bilbao (Spain)

2007-01-16

Production of artifact methylmercury (MeHg{sup +}) during the analysis of two certified reference sediments, CRM-580 and IAEA-405, was investigated. Leaching of the analyte from the solid sample was achieved by ultrasound assisted acidic extraction. The aqueous leachate was either ethylated (NaBEt{sub 4}) or phenylated (NaBPh{sub 4}) using acetic/acetate or citric/citrate to buffer the solution. Preconcentration of the volatile compounds was carried out by extraction with an organic solvent (n-hexane) or solid phase microextraction (SPME). MeHg{sup +} was finally separated and detected by gas chromatography with atomic emission or mass spectrometry detection (GC-MIP-AED or GC-MS). In all the cases the concentrations obtained for MeHg{sup +} in the CRM-580 were significantly higher than the certified value. For the IAEA-405, however, the MeHg{sup +} concentration found was always statistically indistinguishable from the certified value. Experiments were also conducted with synthetic samples, such as aqueous mixtures of MeHg{sup +} and inorganic mercury (Hg{sup 2+}) or silica-gel spiked with both compounds. The methylation rates found (defined as the percentage of Hg{sup 2+} present in the sample which methylates to give artifact MeHg{sup +}) ranged from not observable (in certain synthetic aqueous mixtures) to 0.57% (analysis of CRM-580 under certain conditions). As the amount of Hg{sup 2+} available in the sample seems to be the main factor controlling the magnitude of the artifact, several experiments were conducted using an ionic exchange resin (Dowex M-41) in order to minimise the concentration of this chemical in the reaction medium. First, a hydrochloric leachate of the sample was passed through a microcolumn packed with the exchanger. Second, the resin was mixed with the sample prior to extraction with HCl. In both cases, the predominant Hg{sup 2+} species, HgCl{sub 4} {sup 2-}, was adsorbed on the resin, whereas MeHg{sup +}, mainly as MeHgCl, remained in

Flameless atomic absorption determination of ruthenium using a ''Saturn-1'' spectrophotometer

International Nuclear Information System (INIS)

Pichkov, V.N.; Sinitsyn, N.M.; Sadikova, F.G.; Govorova, M.I.; Yakshinskij, A.I.

1980-01-01

A flameless atomic absorption method is suggested for determining ruthenium in samples of complicated composition using a ''Saturn-1'' spectrophotometer with a L'vov graphite cuvette. The method was used for determining ruthenium in a copper-based sample (10 -3 % Ru) and in electrolyte slurries (10 -3 -10 -2 %). The limit of detection Csub(min, 0.95) = 3.0x10 -3 μg Ru/ml. Other platinum metals do not interfere [ru

ASPECTS OF USE FRACTAL ANALYSIS IN THE EXCHANGE MARKET OF UKRAINE

Directory of Open Access Journals (Sweden)

K. Krytsun

2014-06-01

Full Text Available The paper describes testing of monofractal analysis for obtaining Herst's indicator by Mandelbrot's method on example of exchange rates in the financial market of Ukraine. The assessment shows an adequacy of the results generated by calculating the Hurst parameters for the selected data sample. The study highlights the relationship between the crisis in the market and obtained indicators. Argued the feasibility of using R / S analysis to obtain data on the foreign exchange in the financial market of Ukraine using a small sample volume. Grounded perspective of using this method in the study of the dynamics of financial time series.

Extreme-value dependence: An application to exchange rate markets

Science.gov (United States)

Fernandez, Viviana

2007-04-01

Extreme value theory (EVT) focuses on modeling the tail behavior of a loss distribution using only extreme values rather than the whole data set. For a sample of 10 countries with dirty/free float regimes, we investigate whether paired currencies exhibit a pattern of asymptotic dependence. That is, whether an extremely large appreciation or depreciation in the nominal exchange rate of one country might transmit to another. In general, after controlling for volatility clustering and inertia in returns, we do not find evidence of extreme-value dependence between paired exchange rates. However, for asymptotic-independent paired returns, we find that tail dependency of exchange rates is stronger under large appreciations than under large depreciations.

High-performance ion-exchange chromatography of alkali metals with conductivity detection

International Nuclear Information System (INIS)

Ahmad, M.; Khan, A.R.

1981-01-01

High-performance ion-exchange chromatography of alkali metal and ammonium ions was studied using a conductivity meter as detector. Elution with 0.003 N mitric acid gave excellent resolution. Sensitivity levels, for a 200 micro litre injection, vary from 5 ppm for potassium to 0.1 ppm for lithium. A method to decrease retention times by reducing the exchange capacity of the cation exchange column used by loading it with calciumions, without affecting the resolation, has been described. Application of the method to water, soil and uranium dioxide samples has been demonstrated. (author)

Experimental Study on the Airside Performance of Aluminum Heat Exchangers Having Slim Louver Fins

Energy Technology Data Exchange (ETDEWEB)

Kim, Nae Hyun [Incheon Nat’l Univ., Incheon (Korea, Republic of); Cho, Honggi [Samsung Electronics Daejeon, Suwon (Korea, Republic of)

2017-09-15

Recent trends in slim air conditioners require heat exchangers of reduced flow depth. In this study, slim louver fin geometry was obtained using predictive correlations. The deduced geometry yielded 10 mm flow depth, 0.9 mm louver pitch, and 35° louver angle. Samples were made and tests were conducted. The new slim sample yielded 36% higher j factor and 2.3% higher f factor compared with those of the standard sample. This implies that 26% reduction of heat exchanger volume was possible by reducing the flow depth. In addition, the j/f1/3 of the slim sample was 55% larger than that of the standard sample. Furthermore, the results are compared with predictions made using existing correlations.

Experimental Study on the Airside Performance of Aluminum Heat Exchangers Having Slim Louver Fins

International Nuclear Information System (INIS)

Kim, Nae Hyun; Cho, Honggi

2017-01-01

Recent trends in slim air conditioners require heat exchangers of reduced flow depth. In this study, slim louver fin geometry was obtained using predictive correlations. The deduced geometry yielded 10 mm flow depth, 0.9 mm louver pitch, and 35° louver angle. Samples were made and tests were conducted. The new slim sample yielded 36% higher j factor and 2.3% higher f factor compared with those of the standard sample. This implies that 26% reduction of heat exchanger volume was possible by reducing the flow depth. In addition, the j/f1/3 of the slim sample was 55% larger than that of the standard sample. Furthermore, the results are compared with predictions made using existing correlations.

Radionuclide Leaching from Organic Ion Exchange Resin

International Nuclear Information System (INIS)

Delegard, C.H.; Rinehart, D.E.

1998-01-01

Laboratory tests were performed to examine the efficacy of leach treatments for decontaminating organic ion exchange resins (OIER), which have been found in a number of samples retrieved from K East Basin sludge. Based on process records, the OIER found in the K Basins is a mixed-bet strong acid/strong base material marketed as Purolitetrademark NRW-037. Radionuclides sorbed or associated with the OIER can restrict its disposal to the Environmental Restoration Disposal Facility (ERDF). The need for testing to support development of a treatment process for K Basin sludge has been described in Section 4.2 of ''Testing Strategy to Support the Development of K Basins Sludge Treatment Process'' (Flament 1998). To help understand the effects of anticipated OIER elutriation and washing, tests were performed with well-rinsed OIER material from K East Basin floor sludge (sample H-08 BEAD G) and with well-rinsed OIER having approximately 5% added K East canister composite sludge (sample KECOMP). The rinsed resin-bearing material also contained the inorganic ion exchanger Zeolon-900trademark, a zeolite primarily composed of the mineral mordenite. The zeolite was estimated to comprise 27 weight percent of the dry H-08 BEAD G material

Use of inorganic ion exchange materials for the treatment of liquid waste

International Nuclear Information System (INIS)

El-Naggar, I.M.; Zakaria, E.S.; El-Absy, M.A.; Abdel-Hamid, M.M.; Abo-Mesalam, M.M.; Shady, S.A.; Abdelwahab, M.A.; Aly, H.F.

1997-01-01

To examine the ion exchange behaviour of the double salts of polybasic acid with tetravalent metals type such as cerium(IV) and tin(IV) antimonates, different samples were prepared, heated at different temperatures and exposed to γ-irradiation. These samples were subject to X-ray, infra-red and thermal analysis. The exchange properties of the studied materials improved on increasing the Sb, Ce or Sn molar ratios and the drying temperature. The rate of the isotopic exchange was controlled by particle diffusion for the metal ions studied and was faster as the heating temperature was increased but slower for materials with a higher exchange capacity. The physical thermodynamic parameters have been evaluated which give some information regarding the mechanism of ion exchange on the surface of inorganic materials. The removal of radioactive isotopes of Na + , Cs + , Sr 2+ , Co 2+ and Eu 3+ was carried out by in-situ precipitation or by using preformed precipitate of tin(IV) and cerium(IV) antimonates. The products of in-situ precipitations act as ion exchange materials with high chemical and radioactive stabilities. The new materials have relatively high capacity compared with CeSb and SnSb. The irradiated cerium(IV) antimonate has been successfully used for the quantitative separation of cesium which suggests its use in the treatment of active liquid waste. (author). 24 refs, 7 figs, 17 tabs

Non-equilibrium hydrogen exchange for determination of H-bond strength and water accessibility in solid proteins.

Science.gov (United States)

Grohe, Kristof; Movellan, Kumar Tekwani; Vasa, Suresh Kumar; Giller, Karin; Becker, Stefan; Linser, Rasmus

2017-05-01

We demonstrate measurement of non-equilibrium backbone amide hydrogen-deuterium exchange rates (HDX) for solid proteins. The target of this study are the slowly exchanging residues in solid samples, which are associated with stable secondary-structural elements of proteins. These hydrogen exchange processes escape methods measuring equilibrium exchange rates of faster processes. The method was applied to a micro-crystalline preparation of the SH3 domain of chicken α-spectrin. Therefore, from a 100% back-exchanged micro-crystalline protein preparation, the supernatant buffer was exchanged by a partially deuterated buffer to reach a final protonation level of approximately 20% before packing the sample in a 1.3 mm rotor. Tracking of the HN peak intensities for 2 weeks reports on site-specific hydrogen bond strength and also likely reflects water accessibility in a qualitative manner. H/D exchange can be directly determined for hydrogen-bonded amides using 1 H detection under fast magic angle spinning. This approach complements existing methods and provides the means to elucidate interesting site-specific characteristics for protein functionality in the solid state.

[Determination of soil exchangeable base cations by using atomic absorption spectrophotometer and extraction with ammonium acetate].

Science.gov (United States)

Zhang, Yu-ge; Xiao, Min; Dong, Yi-hua; Jiang, Yong

2012-08-01

A method to determine soil exchangeable calcium (Ca), magnesium (Mg), potassium (K), and sodium (Na) by using atomic absorption spectrophotometer (AAS) and extraction with ammonium acetate was developed. Results showed that the accuracy of exchangeable base cation data with AAS method fits well with the national standard referential soil data. The relative errors for parallel samples of exchangeable Ca and Mg with 66 pair samples ranged from 0.02%-3.14% and 0.06%-4.06%, and averaged to be 1.22% and 1.25%, respectively. The relative errors for exchangeable K and Na with AAS and flame photometer (FP) ranged from 0.06%-8.39% and 0.06-1.54, and averaged to be 3.72% and 0.56%, respectively. A case study showed that the determination method for exchangeable base cations by using AAS was proven to be reliable and trustable, which could reflect the real situation of soil cation exchange properties in farmlands.

Radiocarbon detection by ion charge exchange mass spectrometry

International Nuclear Information System (INIS)

Hotchkis, Michael; Wei, Tao

2007-01-01

A method for detection of radiocarbon at low levels is described and the results of tests are presented. We refer to this method as ion charge exchange mass spectrometry (ICE-MS). The ICE-MS instrument is a two stage mass spectrometer. In the first stage, molecular interferences which would otherwise affect radiocarbon detection at mass 14 are eliminated by producing high charge state ions directly in the ion source (charge state ≥2). 14 N interference is eliminated in the second stage by converting the beam to negative ions in a charge exchange cell. The beam is mass-analysed at each stage. We have built a test apparatus consisting of an electron cyclotron resonance ion source and a pair of analysing magnets with a charge exchange cell in between, followed by an electrostatic analyser to improve the signal to background ratio. With this apparatus we have measured charge exchange probabilities for (C n+ → C - ) from 4.5 to 40.5 keV (n = 1-3). We have studied the sources of background including assessment of limits for nitrogen interference by searching for negative ions from charge exchange of 14 N ions. Our system has been used to detect 14 C in enriched samples of CO 2 gas with 14 C/ 12 C isotopic ratio down to the 10 -9 level. Combined with a measured sample consumption rate of 4 ng/s, this corresponds to a capability to detect transient signals containing only a few μBq of 14 C activity, such as may be obtained from chromatographic separation. The method will require further development to match the sensitivity of AMS with a gas ion source; however, even in its present state its sensitivity is well suited to tracer studies in biomedical research and drug development

Exchange anisotropy pinning of a standing spin-wave mode

Science.gov (United States)

Magaraggia, R.; Kennewell, K.; Kostylev, M.; Stamps, R. L.; Ali, M.; Greig, D.; Hickey, B. J.; Marrows, C. H.

2011-02-01

Standing spin waves in a thin film are used as sensitive probes of interface pinning induced by an antiferromagnet through exchange anisotropy. Using coplanar waveguide ferromagnetic resonance, pinning of the lowest energy spin-wave thickness mode in Ni80Fe20/Ir25Mn75 exchange-biased bilayers was studied for a range of Ir25Mn75 thicknesses. We show that pinning of the standing mode can be used to amplify, relative to the fundamental resonance, frequency shifts associated with exchange bias. The shifts provide a unique “fingerprint” of the exchange bias and can be interpreted in terms of an effective ferromagnetic film thickness and ferromagnet-antiferromagnet interface anisotropy. Thermal effects are studied for ultrathin antiferromagnetic Ir25Mn75 thicknesses, and the onset of bias is correlated with changes in the pinning fields. The pinning strength magnitude is found to grow with cooling of the sample, while the effective ferromagnetic film thickness simultaneously decreases. These results suggest that exchange bias involves some deformation of magnetic order in the interface region.

The Fuge Tube Diode Array Spectrophotometer

Science.gov (United States)

Arneson, B. T.; Long, S. R.; Stewart, K. K.; Lagowski, J. J.

2008-01-01

We present the details for adapting a diode array UV-vis spectrophotometer to incorporate the use of polypropylene microcentrifuge tubes--fuge tubes--as cuvettes. Optical data are presented validating that the polyethylene fuge tubes are equivalent to the standard square cross section polystyrene or glass cuvettes generally used in…

Financial Performance of Health Insurers: State-Run Versus Federal-Run Exchanges.

Science.gov (United States)

Hall, Mark A; McCue, Michael J; Palazzolo, Jennifer R

2018-06-01

Many insurers incurred financial losses in individual markets for health insurance during 2014, the first year of Affordable Care Act mandated changes. This analysis looks at key financial ratios of insurers to compare profitability in 2014 and 2013, identify factors driving financial performance, and contrast the financial performance of health insurers operating in state-run exchanges versus the federal exchange. Overall, the median loss of sampled insurers was -3.9%, no greater than their loss in 2013. Reduced administrative costs offset increases in medical losses. Insurers performed better in states with state-run exchanges than insurers in states using the federal exchange in 2014. Medical loss ratios are the underlying driver more than administrative costs in the difference in performance between states with federal versus state-run exchanges. Policy makers looking to improve the financial performance of the individual market should focus on features that differentiate the markets associated with state-run versus federal exchanges.

Measurement of gross photosynthesis, respiration in the light, and mesophyll conductance using H218O labeling.

Science.gov (United States)

Gauthier, Paul Pg; Battle, Mark O; Griffin, Kevin L; Bender, Michael L

2018-03-27

A fundamental challenge in plant physiology is independently determining the rates of gross O2 production by photosynthesis and O2 consumption by respiration, photorespiration, and other processes. Previous studies on isolated chloroplasts or leaves have separately constrained net and gross O2 production (NOP and GOP, respectively) by labeling ambient O2 with 18O while leaf water was unlabeled. Here, we describe a method to accurately measure GOP and NOP of whole detached leaves in a cuvette as a routine gas exchange measurement. The petiole is immersed in water enriched to a δ18O of ~9,000‰, and leaf water is labeled through the transpiration stream. Photosynthesis transfers 18O from H2O to O2. GOP is calculated from the increase in δ18O of O2 as air passes through the cuvette. NOP is determined from the increase in O2/N2. Both terms are measured by isotope ratio mass spectrometry. CO2 assimilation and other standard gas exchange parameters are also measured. Reproducible measurements are made on a single leaf for more than 15 hours. We used this method to measure the light response curve of NOP and GOP in Phaseolus vulgaris at 21% and 2% O2. We then used these data to examine the O2/CO2 ratio of net photosynthesis, the light response curve of mesophyll conductance, and the apparent inhibition of respiration in the light (Kok effect) at both oxygen levels. The results are discussed in the context of evaluating the technique as a tool to study and understand leaf physiological traits. {copyright, serif} 2018 American Society of Plant Biologists. All rights reserved.

Ion exchange equilibrium constants

CERN Document Server

Marcus, Y

2013-01-01

Ion Exchange Equilibrium Constants focuses on the test-compilation of equilibrium constants for ion exchange reactions. The book first underscores the scope of the compilation, equilibrium constants, symbols used, and arrangement of the table. The manuscript then presents the table of equilibrium constants, including polystyrene sulfonate cation exchanger, polyacrylate cation exchanger, polymethacrylate cation exchanger, polysterene phosphate cation exchanger, and zirconium phosphate cation exchanger. The text highlights zirconium oxide anion exchanger, zeolite type 13Y cation exchanger, and

Field experiment on multicomponent ion exchange in a sandy aquifer

International Nuclear Information System (INIS)

Bjerg, P.L.; Christensen, T.H.

1990-01-01

A field experiment is performed in a sandy aquifer in order to study ion exchange processes and multicomponent solute transport modeling. An injection of groundwater spiked with sodium and potassium chloride was performed over a continuous period of 37 days. The plume is monitored by sampling 350 filters in a spatial grid. The sampling aims at establishing compound (calcium, magnesium, potassium, sodium, chloride) breakthrough curves at various filters 15 to 100 m from the point of injection and areal distribution maps at various cross sections from 0 to 200 m from the point of injection. A three-dimensional multicomponent solute transport model will be used to model the field experiments. The chemical model includes cation exchange, precipitation, dissolution, complexation, ionic strength and the carbonate system. Preliminary results from plume monitoring show that the plume migration is relatively well controlled considering the scale and conditions of the experiment. The transverse dispersion is small causing less dilution than expected. The ion exchange processes have an important influence on the plume composition. Retardation of the injected ions is substantial, especially for potassium. Calcium exhibits a substantial peak following chloride due to release from the ion exchange sites on the sediment. (Author) (8 refs., 5 figs., tab.)

Magnetoresistance of nanogranular Ni/NiO controlled by exchange anisotropy

International Nuclear Information System (INIS)

Del Bianco, L.; Spizzo, F.; Tamisari, M.; Allia, P.

2013-01-01

A link between exchange anisotropy and magnetoresistance has been found to occur in a Ni/NiO sample consisting of Ni nanocrystallites (mean size ∼13 nm, Ni content ∼33 vol%) dispersed in a NiO matrix. This material shows metallic-type electric conduction and isotropic spin-dependent magnetoresistance as well as exchange bias effect. The latter is the outcome of an exchange anisotropy arising from the contact interaction between the Ni phase and the NiO matrix. Combined analysis of magnetization M(H) and magnetoresistance MR(H) loops measured in the 5–250 K temperature range after zero-field-cooling (ZFC) and after field-cooling (FC) from 300 K reveals that the magnetoresistance is influenced by exchange anisotropy, which is triggered by the FC process and can be modified in strength by varying the temperature. Compared to the ZFC case, the exchange anisotropy produces a horizontal shift of the FC MR(H) loop along with a reduction of the MR response associated to the reorientation of the Ni moments. A strict connection between magnetoresistance and remanent magnetization of FC loops on one side and the exchange field on the other, ruled by exchange anisotropy, is indicated. - Highlights: • Nanogranular Ni/NiO with giant magnetoresistance (MR) and exchange bias effect. • Exchange anisotropy produces a shift of the field-cooled MR(H) loop and reduces MR. • MR, remanence of field-cooled loops and exchange field are three correlated quantities. • It is possible to control MR of nanogranular systems through the exchange anisotropy

Energetics of sodium-calcium exchanged zeolite A.

Science.gov (United States)

Sun, H; Wu, D; Guo, X; Shen, B; Navrotsky, A

2015-05-07

A series of calcium-exchanged zeolite A samples with different degrees of exchange were prepared. They were characterized by powder X-ray diffraction (XRD) and differential scanning calorimetry (DSC). High temperature oxide melt drop solution calorimetry measured the formation enthalpies of hydrated zeolites CaNa-A from constituent oxides. The water content is a linear function of the degree of exchange, ranging from 20.54% for Na-A to 23.77% for 97.9% CaNa-A. The enthalpies of formation (from oxides) at 25 °C are -74.50 ± 1.21 kJ mol(-1) TO2 for hydrated zeolite Na-A and -30.79 ± 1.64 kJ mol(-1) TO2 for hydrated zeolite 97.9% CaNa-A. Dehydration enthalpies obtained from differential scanning calorimetry are 32.0 kJ mol(-1) H2O for hydrated zeolite Na-A and 20.5 kJ mol(-1) H2O for hydrated zeolite 97.9% CaNa-A. Enthalpies of formation of Ca-exchanged zeolites A are less exothermic than for zeolite Na-A. A linear relationship between the formation enthalpy and the extent of calcium substitution was observed. The energetic effect of Ca-exchange on zeolite A is discussed with an emphasis on the complex interactions between the zeolite framework, cations, and water.

Amine-functionalized, silver-exchanged zeolite NaY: Preparation, characterization and antibacterial activity

Energy Technology Data Exchange (ETDEWEB)

Hanim, Siti Aishah Mohd; Malek, Nik Ahmad Nizam Nik, E-mail: niknizam@fbb.utm.my; Ibrahim, Zaharah

2016-01-01

Graphical abstract: - Highlights: • Functionalization of Ag-exchanged zeolite NaY with 3-aminopropyltriethoxysilane APTES (ZSA) as antibacterial agent. • Antibacterial assay of ZSA was performed against Escherichia coli ATCC11229 and Staphylococcus aureus ATCC6538. • Functionalization of Ag-exchanged zeolite NaY with APTES significantly increased the antibacterial agent. • Different mechanisms of bacterial death were suggested for each bacteria type by the functionalized Ag-exchanged zeolite NaY. - Abstract: Amine-functionalized, silver-exchanged zeolite NaY (ZSA) were prepared with three different concentrations of 3-aminopropyltriethoxysilane (APTES) (0.01, 0.20 and 0.40 M) and four different concentrations of silver ions (25%, 50%, 100% and 200% from zeolite cation exchange capacity (CEC)). The samples were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray (EDX), surface area analysis, thermogravimetric analysis (TGA) and zeta potential (ZP) analysis. The FTIR results indicated that the zeolite was functionalized by APTES and that the intensity of the peaks corresponding to APTES increased as the concentration of APTES used was increased. The antibacterial activities of the silver-exchanged zeolite NaY (ZS) and ZSA were studied against Escherichia coli ATCC11229 and Staphylococcus aureus ATCC6538 using the disc diffusion technique (DDT) and minimum inhibitory concentration (MIC). The antibacterial activity of ZSA increased with the increase in APTES on ZS, and E. coli was more susceptible towards the sample compared to S. aureus. The FESEM micrographs of the bacteria after contact with the ZSA suggested different mechanisms of bacterial death for these two bacteria due to exposure to the studied sample. The functionalization of ZS with APTES improved the antibacterial activity of the silver-zeolite, depending on the concentration of silver

Use of a polystyrene-divinylbenzene-based weakly acidic cation-exchange resin column and propionic acid as an eluent in ion-exclusion/adsorption chromatography of aliphatic carboxylic acids and ethanol in food samples.

Science.gov (United States)

Mori, Masanobu; Hironaga, Takahiro; Kajiwara, Hiroe; Nakatani, Nobutake; Kozaki, Daisuke; Itabashi, Hideyuki; Tanaka, Kazuhiko

2011-01-01

We developed an ion-exclusion/adsorption chromatography (IEAC) method employing a polystyrene-divinylbenzene-based weakly acidic cation-exchange resin (PS-WCX) column with propionic acid as the eluent for the simultaneous determination of multivalent aliphatic carboxylic acids and ethanol in food samples. The PS-WCX column well resolved mono-, di-, and trivalent carboxylic acids in the acidic eluent. Propionic acid as the eluent gave a higher signal-to-noise ratio, and enabled sensitive conductimetric detection of analyte acids. We found the optimal separation condition to be the combination of a PS-WCX column and 20-mM propionic acid. Practical applicability of the developed method was confirmed by using a short precolumn with a strongly acidic cation-exchange resin in the H(+)-form connected before the separation column; this was to remove cations from food samples by converting them to hydrogen ions. Consequently, common carboxylic acids and ethanol in beer, wine, and soy sauce were successfully separated by the developed method.

The use of ion exchange chromatography methods for the determination of {sup 93}Zr in the samples of radioactive wastes; Vyuzitie metod ionovymennej chromatografie pre stanovenie {sup 93}Zr vo vzorkach radioaktivnych odpadov

Energy Technology Data Exchange (ETDEWEB)

Gardonova, V; Dulanska, S; Remenec, B; Matel, L [Univerzita Komenskeho v Bratislave, Prirodovedecka fakulta, Katedra jadrovej chemie, 84215 Bratislava (Slovakia)

2012-04-25

A simple and rapid method of preconcentration, separation and purification of {sup 93}Zr based on the methods of ion exchange chromatography with ion exchangers made by Eichrom Technologies, Inc. was developed. Multi-stage method of {sup 93}Zr separation proved to be suitable for the analysis of samples highly contaminated with radioactive waste in a relatively short time and with a high decontamination factor. The use and effectiveness of the method was successfully tested by analysis of heterogeneous waste from Mochovce nuclear power plant, which belongs to the most complex matrixes of radiochemical analysis. (authors)

Exploring the microscopic origin of exchange bias with photoelectron emission microscopy (invited)

International Nuclear Information System (INIS)

Scholl, A.; Nolting, F.; Stohr, J.; Regan, T.; Luning, J.; Seo, J. W.; Locquet, J.-P.; Fompeyrine, J.; Anders, S.; Ohldag, H.

2001-01-01

It is well known that magnetic exchange coupling across the ferromagnet - antiferromagnet interface results in an unidirectional magnetic anisotropy of the ferromagnetic layer, called exchange bias. Despite large experimental and theoretical efforts, the origin of exchange bias is still controversial, mainly because detection of the interfacial magnetic structure is difficult. We have applied photoelectron emission microscopy (PEEM) on several ferromagnet - antiferromagnet thin-film structures and microscopically imaged the ferromagnetic and the antiferromagnetic structure with high spatial resolution. Taking advantage of the surface sensitivity and elemental specificity of PEEM, the magnetic configuration and critical properties such as the Neel temperature were determined on LaFeO 3 and NiO thin films and single crystals. On samples coated with a ferromagnetic layer, we microscopically observe exchange coupling across the interface, causing a clear correspondence of the domain structures in the adjacent ferromagnet and antiferromagnet. Field dependent measurements reveal a strong uniaxial anisotropy in individual ferromagnetic domains. A local exchange bias was observed even in not explicitly field-annealed samples, caused by interfacial uncompensated magnetic spins. These experiments provide highly desired information on the relative orientation of electron spins at the interface between ferromagnets and antiferromagnets. [copyright] 2001 American Institute of Physics

Countercurrent exchange of water in canine jejunum

International Nuclear Information System (INIS)

Ryu, K.H.; Grim, E.

1985-01-01

The possibility of countercurrent exchange of water molecules in canine intestinal villi has been examined. Tritium-labeled water ( 3 H 2 O) molecules were introduced either into the fluid lavaging the intestinal lumen or into the arterial blood supply for varying periods of time. Quickly frozen samples of intestinal tissue were sectioned such that isotopic concentrations at the villus tip, midvillus, villus base, and underlying submucosa and muscle could be determined. The villus concentration gradients observed were consistent with the existence of a countercurrent exchange but could also be explained by alternative arrangements. More convincing evidence of a countercurrent was obtained from experiments in which [ 14 C]inulin was introduced simultaneously with 3 H 2 O into the intestinal artery. The villus tip-to-base concentration ratio for 3 H 2 O was less than one while the ratio for inulin was greater than one, thus vitiating the alternative explanations and leading to the conclusion that the labeled water molecules must have undergone a countercurrent exchange

Exchange rate policy

Directory of Open Access Journals (Sweden)

Plačkov Slađana

2013-01-01

Full Text Available Small oscillations of exchange rate certainly affect the loss of confidence in the currency (Serbian dinar, CSD and because of the shallow market even the smallest change in the supply and demand leads to a shift in exchange rate and brings uncertainty. Some economists suggest that the course should be linked to inflation and thus ensure predictable and stable exchange rates. Real exchange rate or slightly depressed exchange rate will encourage the competitiveness of exporters and perhaps ensure the development of new production lines which, in terms of overvalued exchange rate, had no economic justification. Fixed exchange rate will bring lower interest rates, lower risk and lower business uncertainty (uncertainty avoidance, but Serbia will also reduce foreign exchange reserves by following this trend. On the other hand, a completely free exchange rate, would lead to a (real fall of Serbian currency, which in a certain period would lead to a significant increase in exports, but the consequences for businessmen and citizens with loans pegged to the euro exchange rate, would be disastrous. We will pay special attention to the depreciation of the exchange rate, as it is generally favorable to the export competitiveness of Serbia and, on the other hand, it leads to an increase in debt servicing costs of the government as well as of the private sector. Oscillations of the dinar exchange rate, appreciation and depreciation, sometimes have disastrous consequences on the economy, investors, imports and exports. In subsequent work, we will observe the movement of the dinar exchange rate in Serbia, in the time interval 2009-2012, in order to strike a balance and maintain economic equilibrium. A movement of foreign currencies against the local currency is controlled in the foreign exchange market, so in case economic interests require, The National Bank of Serbia (NBS, on the basis of arbitrary criteria, can intervene in the market.

Synthesis, dehydration studies, and cation-exchange behavior of a new phase of niobium(V) phosphate

International Nuclear Information System (INIS)

Qureshi, M.; Ahmad, A.; Shakeel, N.A.; Gupta, A.P.

1986-01-01

Twenty-three samples of niobium(V) phosphate have been synthesized under different conditions using niobium sulfate and phosphoric acid solutions. The amorphous sample having the ion-exchange capacity of 1.06 mEq g -1 and niobium to phosphorus mole ratio of 0.670 was studied in detail for its cation-exchange behavior. Molar distribution coefficients for 25 cations have been studied on this gel at pH 1,2,3, and 5.5. Four quantitative separations of Mg 2+ -Ca 2+ , Mg 2+ -Ba 2+ , Zn 2+ -Cd 2+ , and Bi 3+ -Zn 2+ have successfully been achieved on it. The properties of this sample have been compared with those of niobium arsenate, niobium antimonate, and niobium molybdate. A tentative structural formula is proposed for this sample of niobium phosphate on the basis of chemical composition, cation-exchange capacity, pH-titration, IR spectra, T.G.A., water absorption, and heat treatment data. (author)

Exchange market pressure

NARCIS (Netherlands)

Jager, H.; Klaassen, F.; Durlauf, S.N.; Blume, L.E.

2010-01-01

Currencies can be under severe pressure in the foreign exchange market, but in a fixed (or managed) exchange rate regime that is not fully visible via the change in the exchange rate. Exchange market pressure (EMP) is a concept developed to nevertheless measure the pressure in such cases. This

The influence of post-annealing treatment on the wettability of Ag+/Na+ ion-exchanged soda-lime glasses

International Nuclear Information System (INIS)

Razzaghi, Ahmad; Maleki, Maniya; Azizian-Kalandaragh, Yashar

2013-01-01

In this paper, the effect of thermal annealing and the duration of ion-exchange on the wetting parameters of the Ag + /Na + ion-exchanged glasses have been reported. The analysis of wetting angle in different post-annealing temperatures shows that the wetting angle is increased by increasing the annealing temperature. The wetting parameters of Ag + /Na + ion-exchanged glasses at different ion-exchanged periods of time have been also investigated. Scanning electron microscopy (SEM), UV–Visible spectroscopy and Fourier transform infrared (FTIR) spectroscopy have been used for determination of surface morphology and composition analysis of the prepared samples. The results of SEM show changes in the surface of the samples for different post-annealing temperatures. The optical characterization using UV–Vis spectroscopy shows an increase in the intensity of the absorption peak with increasing the ion-exchange duration. The FTIR spectroscopy confirms the formation of silver oxide material on the surface of Ag + /Na + ion-exchanged glasses.

EXTERNALITIES IN EXCHANGE NETWORKS AN ADAPTATION OF EXISTING THEORIES OF EXCHANGE NETWORKS

NARCIS (Netherlands)

Dijkstra, Jacob

2009-01-01

The present paper extends the focus of network exchange research to externalities in exchange networks. Externalities of exchange are defined as direct effects on an actor's utility, of an exchange in which this actor is not involved. Existing theories in the field of network exchange do not inform

Enhanced exchange anisotropy in IrMn/CoFeB systems and its correlation with uncompensated interfacial spins

DEFF Research Database (Denmark)

Du, Yuqing; Pan, Genhua; Moate, Roy

2010-01-01

Bottom pinned exchange bias systems of IrMn/CoFe and IrMn/CoFeB on CoFe seed layers were studied. Enhanced exchange anisotropy has been observed for IrMn/CoFeB samples annealed at 350 °C. The ferromagnetic and antiferromagnetic layers of both samples are polycrystalline and textured {110} for the...

Determination of organically bound tritium background level in biological samples from a wide area in the south-west of France

International Nuclear Information System (INIS)

Pointurier, F.; Baglan, N.; Alanic, G.; Chiappini, R.

2003-01-01

In this paper, the authors describe a sensitive method for low-level non-exchangeable OBT determination. This methodology combines suitable sample treatment, a combustion apparatus for large-sized samples and low-background liquid scintillation spectrometry, along with precautions that substantially reduce the risks of sample contamination. Great care must be taken in the measurement of non-exchangeable OBT at environmental levels. Many authors have discussed the opportunities for cross-contamination between samples and contamination by exchange with the laboratory atmosphere. The authors also describe an application of the methodology to a large-scale sampling and measurement campaign, aimed at the determination of the environmental non-exchangeable OBT background level in tree leaves and ferns collected on the site and in the vicinity of a research centre located in the south-west of France, not far from Bordeaux. This study constitutes a 'zero level' for the non-exchangeable OBT activity, as, to our knowledge, there is no tritium source within or in the surroundings of the sampled area capable of producing non-exchangeable OBT activities above the natural levels. Our analyses showed that non-exchangeable OBT activities in the collected samples were very low, ranging from below the detection limit (ca 0.7 Bq kg -1 of dry material) to ca 2 Bq kg -1 of dry material. These values are similar to the natural tritium background measured in water samples. No discrepancies can be shown between fern samples and oak tree leaf samples or between samples collected inside and outside the research site

Determination of organically bound tritium background level in biological samples from a wide area in the south-west of France

Energy Technology Data Exchange (ETDEWEB)

Pointurier, F. E-mail: fabien.pointurier@cea.fr; Baglan, N.; Alanic, G.; Chiappini, R

2003-07-01

In this paper, the authors describe a sensitive method for low-level non-exchangeable OBT determination. This methodology combines suitable sample treatment, a combustion apparatus for large-sized samples and low-background liquid scintillation spectrometry, along with precautions that substantially reduce the risks of sample contamination. Great care must be taken in the measurement of non-exchangeable OBT at environmental levels. Many authors have discussed the opportunities for cross-contamination between samples and contamination by exchange with the laboratory atmosphere. The authors also describe an application of the methodology to a large-scale sampling and measurement campaign, aimed at the determination of the environmental non-exchangeable OBT background level in tree leaves and ferns collected on the site and in the vicinity of a research centre located in the south-west of France, not far from Bordeaux. This study constitutes a 'zero level' for the non-exchangeable OBT activity, as, to our knowledge, there is no tritium source within or in the surroundings of the sampled area capable of producing non-exchangeable OBT activities above the natural levels. Our analyses showed that non-exchangeable OBT activities in the collected samples were very low, ranging from below the detection limit (ca 0.7 Bq kg{sup -1} of dry material) to ca 2 Bq kg{sup -1} of dry material. These values are similar to the natural tritium background measured in water samples. No discrepancies can be shown between fern samples and oak tree leaf samples or between samples collected inside and outside the research site.

Heat exchanger

International Nuclear Information System (INIS)

Leigh, D.G.

1976-01-01

The arrangement described relates particularly to heat exchangers for use in fast reactor power plants, in which heat is extracted from the reactor core by primary liquid metal coolant and is then transferred to secondary liquid metal coolant by means of intermediate heat exchangers. One of the main requirements of such a system, if used in a pool type fast reactor, is that the pressure drop on the primary coolant side must be kept to a minimum consistent with the maintenance of a limited dynamic head in the pool vessel. The intermediate heat exchanger must also be compact enough to be accommodated in the reactor vessel, and the heat exchanger tubes must be available for inspection and the detection and plugging of leaks. If, however, the heat exchanger is located outside the reactor vessel, as in the case of a loop system reactor, a higher pressure drop on the primary coolant side is acceptable, and space restriction is less severe. An object of the arrangement described is to provide a method of heat exchange and a heat exchanger to meet these problems. A further object is to provide a method that ensures that excessive temperature variations are not imposed on welded tube joints by sudden changes in the primary coolant flow path. Full constructional details are given. (U.K.)

Measurement of cation exchange capacity (CEC) on natural zeolite by percolation method

Science.gov (United States)

Wiyantoko, Bayu; Rahmah, Nafisa

2017-12-01

The cation exchange capacity (CEC)measurement has been carried out in natural zeolite by percolation method. The natural zeolite samples used for cation exchange capacity measurement were activated beforehand with physical activation and chemical activation. The physically activated zeolite was done by calcination process at 600 °C for 4 hours. The natural zeolite was activated chemically by using sodium hydroxide by refluxing process at 60-80 °C for 3 hours. In summary, cation exchange capacity (CEC) determination was performed by percolation, distillation and titration processes. Based on the measurement that has been done, the exchange rate results from physical activated and chemical activated of natural zeolite were 181.90cmol (+)/kg and 901.49cmol (+)/kg respectively.

Study of switching behavior of exchange-coupled nanomagnets by transverse magnetization metrology

Science.gov (United States)

Dey, Himadri S.; Csaba, Gyorgy; Bernstein, Gary H.; Porod, Wolfgang

2017-05-01

We investigate the static switching modes of nanomagnets patterned from antiferromagnetically exchange-coupled magnetic multilayers, and compare them to nanomagnets having only dipole coupling between the ferromagnetic layers. Vibrating sample magnetometry experiments, supported by micromagnetic simulations, reveal two distinct switching mechanisms between the exchange-coupled and only dipole-coupled nanomagnets. The exchange-coupled nanomagnets exhibit gradual switching of the layers, dictated by the strong antiferromagnetic exchange coupling present between the layers. However, the layers of the only dipole-coupled nanomagnets show abrupt nucleation/growth type switching. A comprehensive understanding of the switching modes of such layered and patterned systems can add new insight into the reversal mechanisms of similar systems employed for spintronic and magneto-logic device applications.

Estimating Exchange Market Pressure and the Degree of Exchange Market Intervention for Finland during the Floating Exchange Rate Regime

OpenAIRE

Pösö, Mika; Spolander, Mikko

1997-01-01

In this paper, we use a fairly simple monetary macro model to calculate the quarterly measures of exchange market pressure and the degree of the Bank of Finland's intervention during the time the markka was floated. Exchange market pressure measures the size of the exchange rate change that would have occurred if the central bank had unexpectedly refrained from intervening in the foreign exchange market. Intervention activity of the central bank is measured as the proportion of exchange marke...

Coupling on-line preconcentration by ion-exchange with ETAAS. A novel flow injection approach based on the use of a renewable microcolumn as demonstrated for the determination of nickel in environmental and biological samples

DEFF Research Database (Denmark)

Wang, Jianhua; Hansen, Elo Harald

2000-01-01

microcolumn incorporated within an integrated micro FI-system, the column is loaded with a defined volume of small beads of an SP Sephadex C-25 cation-exchange resin and subsequently exposed to a metered amount of sample solution. However, instead of eluting the retained analyte from the organic ion-exchange......A novel way of exploiting flow injection/sequential injection (FIA/SIA) on-line ion-exchange preconcentration with detection by electrothermal atomic absorption spectrometry (ETAAS) is described and demonstrated for the determination of trace-levels of nickel. Based on the use of a renewable...... resin, the beads are along with 30 mul of carrier (buffer) solution transported via air segmentation directly into the graphite tube, where they are ashed during the pyrolysis and atomization process. The ETAAS determination is performed in parallel with the preconcentration process of the ensuing...

Foreign Exchange Exposure of A Selected Number of Swedish Multinationals : The Capital Market Approach

OpenAIRE

Shudzeka, Basile N; Kum, Hyceinth N.

2007-01-01

This research work analyses the impact of exchange rate fluctuations on firm value. It is based on a sample of 10 Swedish multinational companies selected from two market capitalization segments (Mid and Large Cap) according to the OMX index classification. A multiple linear regression model is used to explore the dependency of the log returns (continuously compounded returns) of each of the sampled companies to the percentage changes in the spot exchange rates for the SEK/U.S. Dollar and SEK...

The new Chalk River AMS ion source, sample changer and external sample magazine

International Nuclear Information System (INIS)

Koslowsky, V.T.; Bray, N.; Imahori, Y.; Andrews, H.R.; Davies, W.G.

1997-01-01

A new sample magazine, sample changer and ion source have been developed and are in routine use at Chalk River. The system features a readily accessible 40-sample magazine at ground potential that is external to the ion source and high-voltage cage. The samples are held in an inert atmosphere and can be individually examined or removed; they can be exchanged en masse as a complete magazine concurrent with an AMS measurement. On-line sample changing is done with a pneumatic rabbit transfer system employing two stages of differential pumping. At Chalk River this is routinely performed across a 200 kV potential. Sample positioning is precise, and hundreds of 36 Cl and 129 I samples have been measured over a period of several days without interruption or alteration of ion source operating conditions. (author)

The Emotional Intelligence of Leaders as Antecedent to Leader-Member Exchanges: A Field Study

Science.gov (United States)

Barbuto, John E., Jr.; Bugenhagen, Marilyn J.

2009-01-01

Eighty elected leaders and 388 followers were sampled to test the relationships between leaders' emotional intelligence and the quality of leader-member exchange. Results of the field study found a significant relationship between leaders' emotional intelligence (total) and leader-member exchange quality. Specific subscales of emotional…

Bayesian analysis for exponential random graph models using the adaptive exchange sampler

KAUST Repository

Jin, Ick Hoon

2013-01-01

Exponential random graph models have been widely used in social network analysis. However, these models are extremely difficult to handle from a statistical viewpoint, because of the existence of intractable normalizing constants. In this paper, we consider a fully Bayesian analysis for exponential random graph models using the adaptive exchange sampler, which solves the issue of intractable normalizing constants encountered in Markov chain Monte Carlo (MCMC) simulations. The adaptive exchange sampler can be viewed as a MCMC extension of the exchange algorithm, and it generates auxiliary networks via an importance sampling procedure from an auxiliary Markov chain running in parallel. The convergence of this algorithm is established under mild conditions. The adaptive exchange sampler is illustrated using a few social networks, including the Florentine business network, molecule synthetic network, and dolphins network. The results indicate that the adaptive exchange algorithm can produce more accurate estimates than approximate exchange algorithms, while maintaining the same computational efficiency.

Psychological contract breach and work performance:Is social exchange a buffer or an intensifier?

OpenAIRE

Bal, P. Matthijs; Chiaburu, Dan S.; Jansen, Paul G. W.

2010-01-01

Purpose: The aim of this paper is to investigate how social exchanges modify the relationship between psychological contract breach and work performance. It aims to present two concurrent hypotheses, based on theoretical interaction effects of social exchanges (conceptualized as social exchange relationships, POS, and trust). Design/methodology/approach: Data were collected from a sample of 266 employees in a service sector company in the USA. Regression analysis was used to explore the moder...

In-situ ionic liquid dispersive liquid-liquid microextraction using a new anion-exchange reagent combined Fe3O4 magnetic nanoparticles for determination of pyrethroid pesticides in water samples.

Science.gov (United States)

Fan, Chen; Liang, You; Dong, Hongqiang; Ding, Guanglong; Zhang, Wenbing; Tang, Gang; Yang, Jiale; Kong, Dandan; Wang, Deng; Cao, Yongsong

2017-07-04

In this work, in-situ ionic liquid dispersive liquid-liquid microextraction combined ultrasmall Fe 3 O 4 magnetic nanoparticles was developed as a kind of pretreatment method to detect pyrethroid pesticides in water samples. New anion-exchange reagents including Na[DDTC] and Na[N(CN) 2 ] were optimized for in-situ extraction pyrethroids, which showed enhanced microextraction performance. Pyrethroids were enriched by hydrophilic ionic liquid [P 4448 ][Br] (aqueous solution, 200 μL, 0.2 mmol mL -1 ) reaction in-situ with anion-exchange reagent Na[N(CN) 2 ] (aqueous solution, 300 μL, 0.2 mmol mL -1 ) forming hydrophobic ionic liquid as extraction agent in water sample (10 mL). Ultrasmall superparamagnetic iron oxide nanoparticles (30 mg) were used to collect the mixture of ionic liquid and pyrethroids followed by elution with acetonitrile. The extraction of ionic liquid strategies was unique and efficiently fulfilled with high enrichment factors (176-213) and good recoveries (80.20-117.31%). The method was successively applied to the determination of pyrethroid pesticides in different kinds of water samples with the limits of detection ranged from 0.16 to 0.21 μg L -1 . The proposed method is actually nanometer-level microextraction (average size 80 nm) with the advantages of simplicity, rapidity, and sensitivity. Copyright © 2017 Elsevier B.V. All rights reserved.

A continuous exchange factor method for radiative exchange in enclosures with participating media

International Nuclear Information System (INIS)

Naraghi, M.H.N.; Chung, B.T.F.; Litkouhi, B.

1987-01-01

A continuous exchange factor method for analysis of radiative exchange in enclosures is developed. In this method two types of exchange functions are defined, direct exchange function and total exchange function. Certain integral equations relating total exchange functions to direct exchange functions are developed. These integral equations are solved using Gaussian quadrature integration method. The results obtained based on the present approach are found to be more accurate than those of the zonal method

The Radioecology Exchange

Energy Technology Data Exchange (ETDEWEB)

Barnett, Catherine L.; Beresford, Nicholas A.; Patel, Sabera; Wells, Claire; Howard, Brenda J. [NERC Centre for Ecology and Hydrology, CEH Lancaster, Lancaster Environment Centre, Library Av., Bailrigg, Lancaster, LA1 4AP (United Kingdom); Mora, Juan Carlos; Real, Almudena [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Avenida complutense 22, Madrid, 28040 (Spain); Beaugelin-Seiller, Karine; Gilbin, Rodolphe; Hinton, Thomas [IRSN-Institut de Radioprotection et de Surete Nucleaire, 31, Avenue de la Division Leclerc, 92260 Fontenay-Aux-Roses (France); Vesterbacka, Pia; Muikku, Maarit; Outola, Iisa [Radiation and Nuclear Safety Authority, P.O. Box 14, FI-00881 Helsinki (Finland); Skuterud, Lavrans; AlbumYtre-Eide, Martin [Norwegian Radiation Protection Authority, Grini Naeringspark 13, Oesteraas, 1332 (Norway); Bradshaw, Clare; Stark, Karolina; Jaeschke, Ben [Stockholms Universitet, Universitetsvaegen 10, Stockholm, 10691 (Sweden); Oughton, Deborah; Skipperud, Lindis [NMBU Norwegian University of Life Science P.O. Box 5003N-1432 Aas, Oslo (Norway); Vandenhove, Hildegarde; Vanhoudt, Nathalie [SCK.CEN, Studiecentrum voor Kernenergie/Centre d' Etude de l' Energie Nucleaire, Avenue Herrmann-Debroux 40, BE-1160 Brussels (Belgium); Willrodt, Christine; Steiner, Martin [Bundesamt fuer Strahlenschutz, Willy-Brandt-Strasse 5, 38226 Salzgitter (Germany)

2014-07-01

The Radioecology Exchange (www.radioecology-exchange.org) was created in 2011 under the EU FP7 STAR (Strategy for Allied Radioecology) network of excellence. The project aims to integrate the research efforts on radioecology of nine European organisations into a sustainable network. The web site (together with associated Twitter feeds and Facebook page) currently provides the gateway to project outputs and other on-line radiation protection and radioecological resources. In 2013, the EU FP7 COMET (Coordination and implementation of a pan-European instrument for radioecology) project commenced; it aims to strengthen research on the impact of radiation on man and the environment. COMET includes the STAR partners with the addition of one Japanese and two Ukrainian research institutes. As STAR and COMET interact closely together and with the European Radioecology Alliance (www.er-alliance.org/), the Radioecology Exchange will be modified to become an international 'hub' for information related to radioecology. Project specific information will be hosted on separate web sites www.star-radioecology.org and www.comet-radioecology.org. This paper will present an overview of the resources hosted on the Radioecology Exchange inviting other scientists to contribute. Highlighted aspects of the site include: Social media (News blog, Twitter, Facebook) - Items announcing project outputs, training courses, jobs, studentships etc. Virtual laboratory - Information which encourages integration through joint research and integrated use of data and sample materials. These pages will focus on three categories: (1) Methodological: descriptions and video clips of commonly used analytical methods and protocols and the procedures used in STAR and COMET; (2) Informative: databases made available by STAR/COMET partners together with details of sample archives held. Fact-sheets on radio-ecologically important radionuclides and 'topical descriptions' which show absorbed

The Radioecology Exchange

Energy Technology Data Exchange (ETDEWEB)

Barnett, Catherine L.; Beresford, Nicholas A.; Patel, Sabera; Wells, Claire; Howard, Brenda J. [NERC Centre for Ecology and Hydrology, CEH Lancaster, Lancaster Environment Centre, Library Av., Bailrigg, Lancaster, LA1 4AP (United Kingdom); Mora, Juan Carlos; Real, Almudena [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Avenida complutense 22, Madrid, 28040 (Spain); Beaugelin-Seiller, Karine; Gilbin, Rodolphe; Hinton, Thomas [IRSN-Institut de Radioprotection et de Surete Nucleaire, 31, Avenue de la Division Leclerc, 92260 Fontenay-Aux-Roses (France); Vesterbacka, Pia; Muikku, Maarit; Outola, Iisa [Radiation and Nuclear Safety Authority, P.O. Box 14, FI-00881 Helsinki (Finland); Skuterud, Lavrans; AlbumYtre-Eide, Martin [Norwegian Radiation Protection Authority, Grini Naeringspark 13, Oesteraas, 1332 (Norway); Bradshaw, Clare; Stark, Karolina; Jaeschke, Ben [Stockholms Universitet, Universitetsvaegen 10, Stockholm, 10691 (Sweden); Oughton, Deborah; Skipperud, Lindis [NMBU Norwegian University of Life Science P.O. Box 5003N-1432 Aas, Oslo (Norway); Vandenhove, Hildegarde; Vanhoudt, Nathalie [SCK.CEN, Studiecentrum voor Kernenergie/Centre d' Etude de l' Energie Nucleaire, Avenue Herrmann-Debroux 40, BE-1160 Brussels (Belgium); Willrodt, Christine; Steiner, Martin [Bundesamt fuer Strahlenschutz, Willy-Brandt-Strasse 5, 38226 Salzgitter (Germany)

2014-07-01

The Radioecology Exchange (www.radioecology-exchange.org) was created in 2011 under the EU FP7 STAR (Strategy for Allied Radioecology) network of excellence. The project aims to integrate the research efforts on radioecology of nine European organisations into a sustainable network. The web site (together with associated Twitter feeds and Facebook page) currently provides the gateway to project outputs and other on-line radiation protection and radioecological resources. In 2013, the EU FP7 COMET (Coordination and implementation of a pan-European instrument for radioecology) project commenced; it aims to strengthen research on the impact of radiation on man and the environment. COMET includes the STAR partners with the addition of one Japanese and two Ukrainian research institutes. As STAR and COMET interact closely together and with the European Radioecology Alliance (www.er-alliance.org/), the Radioecology Exchange will be modified to become an international 'hub' for information related to radioecology. Project specific information will be hosted on separate web sites www.star-radioecology.org and www.comet-radioecology.org. This paper will present an overview of the resources hosted on the Radioecology Exchange inviting other scientists to contribute. Highlighted aspects of the site include: Social media (News blog, Twitter, Facebook) - Items announcing project outputs, training courses, jobs, studentships etc. Virtual laboratory - Information which encourages integration through joint research and integrated use of data and sample materials. These pages will focus on three categories: (1) Methodological: descriptions and video clips of commonly used analytical methods and protocols and the procedures used in STAR and COMET; (2) Informative: databases made available by STAR/COMET partners together with details of sample archives held. Fact-sheets on radio-ecologically important radionuclides and 'topical descriptions' which show absorbed dose estimations for

Electron exchange reaction in anion exchangers as observed in uranium isotope separation

International Nuclear Information System (INIS)

Obanawa, Heiichiro; Takeda, Kunihiko; Seko, Maomi

1991-01-01

The mechanism of electron exchange in an ion exchanger, as occurring between U 4+ and UO 2 2+ in uranium isotope separation, was investigated. The height of the separation unit (H q ) in the presence of metal ion catalysts, as obtained from the separation experiments, was found to be almost coincident with the theoretical value of H q as calculated on the basis of the intrasolution acceleration mechanism of the metal ion, suggesting that the electron exchange mechanism in the ion-exchanger is essentially the same as that in the solution when metal ion catalysts are present. Separation experiments with no metal ion catalyst, on the other hand, showed the electron exchange reaction in the ion exchanger to be substantially higher than that in the solution, suggesting an acceleration of the electron exchange reaction by the ion-exchanger which is due to the close existence of higher order Cl - complexes of UO 2 2+ and U 4+ in the vicinity of the ion-exchange group. (author)

Surface area of antimony oxide by isotope exchange and other methods

Energy Technology Data Exchange (ETDEWEB)

Rao, Y.K.; Acharya, B.V.; Rangamannar, B.

1985-06-17

Specific surface areas of antimony oxide samples, one commercial, the other prepared from antimony trichloride were measured by heterogeneous isotope exchange, gas adsorption, air permeability and microscopic methods. Specific surface areas obtained by these four methods for the two samples were compared and the observed differences are explained.

Investigation of Chemical Exchange at Intermediate Exchange Rates using a Combination of Chemical Exchange Saturation Transfer (CEST) and Spin-Locking methods (CESTrho)

Science.gov (United States)

Kogan, Feliks; Singh, Anup; Cai, Keija; Haris, Mohammad; Hariharan, Hari; Reddy, Ravinder

2011-01-01

Proton exchange imaging is important as it allows for visualization and quantification of the distribution of specific metabolites with conventional MRI. Current exchange mediated MRI methods suffer from poor contrast as well as confounding factors that influence exchange rates. In this study we developed a new method to measure proton exchange which combines chemical exchange saturation transfer (CEST) and T1ρ magnetization preparation methods (CESTrho). We demonstrated that this new CESTrho sequence can detect proton exchange in the slow to intermediate exchange regimes. It has a linear dependence on proton concentration which allows it to be used to quantitatively measure changes in metabolite concentration. Additionally, the magnetization scheme of this new method can be customized to make it insensitive to changes in exchange rate while retaining its dependency on solute concentration. Finally, we showed the feasibility of using CESTrho in vivo. This sequence is able to detect proton exchange at intermediate exchange rates and is unaffected by the confounding factors that influence proton exchange rates thus making it ideal for the measurement of metabolites with exchangeable protons in this exchange regime. PMID:22009759

Investigation of chemical exchange at intermediate exchange rates using a combination of chemical exchange saturation transfer (CEST) and spin-locking methods (CESTrho).

Science.gov (United States)

Kogan, Feliks; Singh, Anup; Cai, Keija; Haris, Mohammad; Hariharan, Hari; Reddy, Ravinder

2012-07-01

Proton exchange imaging is important as it allows for visualization and quantification of the distribution of specific metabolites with conventional MRI. Current exchange mediated MRI methods suffer from poor contrast as well as confounding factors that influence exchange rates. In this study we developed a new method to measure proton exchange which combines chemical exchange saturation transfer and T(1)(ρ) magnetization preparation methods (CESTrho). We demonstrated that this new CESTrho sequence can detect proton exchange in the slow to intermediate exchange regimes. It has a linear dependence on proton concentration which allows it to be used to quantitatively measure changes in metabolite concentration. Additionally, the magnetization scheme of this new method can be customized to make it insensitive to changes in exchange rate while retaining its dependency on solute concentration. Finally, we showed the feasibility of using CESTrho in vivo. This sequence is able to detect proton exchange at intermediate exchange rates and is unaffected by the confounding factors that influence proton exchange rates thus making it ideal for the measurement of metabolites with exchangeable protons in this exchange regime. Copyright © 2011 Wiley Periodicals, Inc.

On one pion exchange potential with quark exchange in the resonating group method

International Nuclear Information System (INIS)

Braeuer, K.; Faessler, A.; Fernandez, F.; Shimizu, K.

1985-01-01

The effect of quark exchange between different nucleons on the one pion exchange potential is studied in the framework of the resonating group method. The calculated phase shifts including the one pion exchange potential with quark exchange in addition to the one gluon plus sigma meson exchange are shown to be consistent with experiments. Especially the p-wave phase shifts are improved by taking into account the quark exchange on the one pion exchange potential. (orig.)

Multiple capillary biochemical analyzer

Science.gov (United States)

Dovichi, N.J.; Zhang, J.Z.

1995-08-08

A multiple capillary analyzer allows detection of light from multiple capillaries with a reduced number of interfaces through which light must pass in detecting light emitted from a sample being analyzed, using a modified sheath flow cuvette. A linear or rectangular array of capillaries is introduced into a rectangular flow chamber. Sheath fluid draws individual sample streams through the cuvette. The capillaries are closely and evenly spaced and held by a transparent retainer in a fixed position in relation to an optical detection system. Collimated sample excitation radiation is applied simultaneously across the ends of the capillaries in the retainer. Light emitted from the excited sample is detected by the optical detection system. The retainer is provided by a transparent chamber having inward slanting end walls. The capillaries are wedged into the chamber. One sideways dimension of the chamber is equal to the diameter of the capillaries and one end to end dimension varies from, at the top of the chamber, slightly greater than the sum of the diameters of the capillaries to, at the bottom of the chamber, slightly smaller than the sum of the diameters of the capillaries. The optical system utilizes optic fibers to deliver light to individual photodetectors, one for each capillary tube. A filter or wavelength division demultiplexer may be used for isolating fluorescence at particular bands. 21 figs.

Measurements on cation exchange capacity of bentonite in the long-term test of buffer material (LOT)

International Nuclear Information System (INIS)

Muurinen, A.

2011-01-01

Determination of cation exchange capacity (CEC) of bentonite in the LOT experiment was the topic of this study. The measurements were performed using the complex of copper(II) ion with trietylenetetramine [Cu(trien)] 2+ as the index cation. Testing of the determination method suggested that (i) drying and wetting of the bentonite, and (ii) exchange time affect the obtained result. The real CEC measurements were carried out with the bentonite samples taken from the A2 parcel of the LOT experiment. The CEC values of the LOT samples were compared with those of the reference samples taken from the same bentonite batch before the compaction of the blocks for the experiment. The conclusions drawn have been made on the basis of the results determined with the wet bentonite samples using the direct exchange of two weeks with 0.01 M [Cu(trien)] 2+ solution because this method gave the most complete cation exchange in the CEC measurements. The differences between the samples taken from different places of the A2 parcel were quite small and close to the accuracy of the method. However, it seems that the CEC values of the field experiment are somewhat higher than the CEC of the reference samples and the values of the hot area are higher than those obtained from the low temperature area. It is also obvious that the variation of CEC increases with increasing temperature. (orig.)

Automation of a battery of ion exchange columns for the determination of Pu in biological samples

International Nuclear Information System (INIS)

Jeanmaire, L.; Ballada, J.; Rigaudiere, R.; Patti, F.; Clanet, F.

1967-01-01

The document describes an apparatus allowing ten automatic and simultaneous determination of plutonium by ion exchange resins in urine. The constant flow rate reactants supply is realized by plastic siphons. The different determination phases are controlled by a programmer. (A.L.B.) [fr

Dual channel detection of ultra low concentration of bacteria in real time by scanning fluorescence correlation spectroscopy

Science.gov (United States)

Altamore, Ilaria; Lanzano, Luca; Gratton, Enrico

2013-06-01

We describe a novel method to detect very low concentrations of bacteria in water. Our device consists of a portable horizontal geometry small confocal microscope with large pinhole and a holder for cylindrical cuvettes containing the sample. Two motors provide fast rotational and slow vertical motion of the cuvette so the device looks like a simplified flow cytometer without flow. To achieve high sensitivity, the design has two detection channels. Bacteria are stained by two different nucleic acid dyes and excited with two different lasers. Data are analyzed with a correlation filter based on particle passage pattern recognition. The passage of a particle through the illumination volume is compared with a Gaussian pattern in both channels. The width of the Gaussian correlates with the time of passage of the particle so one particle is counted when the algorithm finds a match with a Gaussian in both channels. The concentration of particles in the sample is deduced from the total number of coincident hits and the total volume scanned. This portable setup provides higher sensitivity, low-cost advantage, and it can have a wide use ranging from clinical applications to pollution monitors and water and air quality control.

Dual channel detection of ultra low concentration of bacteria in real time by scanning fluorescence correlation spectroscopy

International Nuclear Information System (INIS)

Altamore, Ilaria; Lanzano, Luca; Gratton, Enrico

2013-01-01

We describe a novel method to detect very low concentrations of bacteria in water. Our device consists of a portable horizontal geometry small confocal microscope with large pinhole and a holder for cylindrical cuvettes containing the sample. Two motors provide fast rotational and slow vertical motion of the cuvette so the device looks like a simplified flow cytometer without flow. To achieve high sensitivity, the design has two detection channels. Bacteria are stained by two different nucleic acid dyes and excited with two different lasers. Data are analyzed with a correlation filter based on particle passage pattern recognition. The passage of a particle through the illumination volume is compared with a Gaussian pattern in both channels. The width of the Gaussian correlates with the time of passage of the particle so one particle is counted when the algorithm finds a match with a Gaussian in both channels. The concentration of particles in the sample is deduced from the total number of coincident hits and the total volume scanned. This portable setup provides higher sensitivity, low-cost advantage, and it can have a wide use ranging from clinical applications to pollution monitors and water and air quality control. (paper)

Rapid Sequential in Situ Multiplexing with DNA Exchange Imaging in Neuronal Cells and Tissues.

Science.gov (United States)

Wang, Yu; Woehrstein, Johannes B; Donoghue, Noah; Dai, Mingjie; Avendaño, Maier S; Schackmann, Ron C J; Zoeller, Jason J; Wang, Shan Shan H; Tillberg, Paul W; Park, Demian; Lapan, Sylvain W; Boyden, Edward S; Brugge, Joan S; Kaeser, Pascal S; Church, George M; Agasti, Sarit S; Jungmann, Ralf; Yin, Peng

2017-10-11

To decipher the molecular mechanisms of biological function, it is critical to map the molecular composition of individual cells or even more importantly tissue samples in the context of their biological environment in situ. Immunofluorescence (IF) provides specific labeling for molecular profiling. However, conventional IF methods have finite multiplexing capabilities due to spectral overlap of the fluorophores. Various sequential imaging methods have been developed to circumvent this spectral limit but are not widely adopted due to the common limitation of requiring multirounds of slow (typically over 2 h at room temperature to overnight at 4 °C in practice) immunostaining. We present here a practical and robust method, which we call DNA Exchange Imaging (DEI), for rapid in situ spectrally unlimited multiplexing. This technique overcomes speed restrictions by allowing for single-round immunostaining with DNA-barcoded antibodies, followed by rapid (less than 10 min) buffer exchange of fluorophore-bearing DNA imager strands. The programmability of DEI allows us to apply it to diverse microscopy platforms (with Exchange Confocal, Exchange-SIM, Exchange-STED, and Exchange-PAINT demonstrated here) at multiple desired resolution scales (from ∼300 nm down to sub-20 nm). We optimized and validated the use of DEI in complex biological samples, including primary neuron cultures and tissue sections. These results collectively suggest DNA exchange as a versatile, practical platform for rapid, highly multiplexed in situ imaging, potentially enabling new applications ranging from basic science, to drug discovery, and to clinical pathology.

Formation of silver colloids on ion exchanged soda lime silicate glasses by irradiation

International Nuclear Information System (INIS)

Yoshimura, E.M.; Okuno, E.

1998-01-01

The effect of ionizing radiation (gamma rays, X-rays and electrons) on soda lime silicate glasses, in which part of the Na + was substituted by Ag + by means of an ionic exchange process, was studied. The techniques of thermally stimulated depolarization current (TSDC) and transmission electron microscopy (TEM) were employed to follow the formation of silver colloids by irradiation. Also the thermoluminescence (TL) of the samples was measured and three peaks between room temperature and 450 C were observed. The TEM and TSDC results agree that, as expected, ionizing radiation promotes the formation of silver colloids on the ion exchanged surface of soda lime glasses. Soft X-rays are much more efficient in the process than gamma rays and electrons. The correlation with thermoluminescence glow curves indicates that the intensity of a TL peak at 230 C can provide a rapid means of evaluating the presence of silver colloids. TL sensitivities, measured as area under the glow curve per unit mass and unit dose, are very similar for ion exchanged and not exchanged samples submitted to X-ray irradiation, although the peak temperatures differ in about 40 C in the two cases. For both electron and gamma irradiated samples, the TL sensitivity drops about an order of magnitude when compared to the X-ray irradiated ones. (orig.)

Optimization of spring exchange coupled ferrites, studied by in situ neutron diffraction

DEFF Research Database (Denmark)

Ahlburg, Jakob; Christensen, Mogens; Granados-Miralles, Cecilia

have a spin it will also be possible to measure a magnetic signal and investigate the exchange-coupling. After the reduction the samples was furthermore investigated using powder x-ray diffraction and VSM (vibrating sample magnetometer). To understand the reaction mechanism, a series of experiments...

Exchange bias in Co nanoparticles embedded in an Mn matrix

International Nuclear Information System (INIS)

Domingo, Neus; Testa, Alberto M.; Fiorani, Dino; Binns, Chris; Baker, Stephen; Tejada, Javier

2007-01-01

Magnetic properties of Co nanoparticles of 1.8 nm diameter embedded in Mn and Ag matrices have been studied as a function of the volume fraction (VFF). While the Co nanoparticles in the Ag matrix show superparamagnetic behavior with T B =9.5 K (1.5% VFF) and T B =18.5 K (8.9% VFF), the Co nanoparticles in the antiferromagnetic Mn matrix show a transition peak at ∼65 K in the ZFC/FC susceptibility measurements, and an increase of the coercive fields at low temperature with respect to the Ag matrix. Exchange bias due to the interface exchange coupling between Co particles and the antiferromagnetic Mn matrix has also been studied. The exchange bias field (H eb ), observed for all Co/Mn samples below 40 K, decreases with decreasing volume fraction and with increasing temperature and depends on the field of cooling (H fc ). Exchange bias is accompanied by an increase of coercivity

On-line stable isotope measurements during plant and soil gas exchange

International Nuclear Information System (INIS)

Yakir, D.

2001-01-01

Recent techniques for on-line stable isotope measurements during plant and soil exchange of CO 2 and/or water vapor are briefly reviewed. For CO 2 , these techniques provide means for on-line measurements of isotopic discrimination during CO 2 exchange by leaves in the laboratory and in the field, of isotopic discrimination during soil respiration and during soil-atmosphere CO 2 exchange, and of isotopic discrimination in O 2 during plant respiration. For water vapor, these techniques provide means to measure oxygen isotopic composition of water vapor during leaf transpiration and for the analysis of sub microliter condensed water vapor samples. Most of these techniques involve on-line sampling of CO 2 and water vapor from a dynamic, intact soil or plant system. In the laboratory, these systems also allow on-line isotopic analysis by continuous-flow isotope ratio mass spectrometry. The information obtained with these on-line techniques is becoming increasingly valuable, and often critical, for ecophysiologial research and in the study of biosphere-atmosphere interactions. (author)

Methods of selenium and tellurium determination in geological and enviromental materials

International Nuclear Information System (INIS)

Nazarenko, I.I.; Kislova, I.V.

1988-01-01

Atomic-absorption and atomic-emission methods of tellurium determination in ores and products of their processing are described. Flame variant with extractional concentration permits to determine tellurium with the concentration up to 6x10 -6 %, the use of graphite cuvette after preliminary concentration-up to 1x10 -6 %. Atomic-emissional method permits to determine 3x10 -4 % Te from sample of 0.5 g

17 CFR Appendix B to Part 420 - Sample Large Position Report

Science.gov (United States)

2010-04-01

..., and as collateral for financial derivatives and other securities transactions $ Total Memorandum 1... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Sample Large Position Report B Appendix B to Part 420 Commodity and Securities Exchanges DEPARTMENT OF THE TREASURY REGULATIONS UNDER...

Switching field of partially exchange-coupled particles

International Nuclear Information System (INIS)

Oliva, M.I.; Bertorello, H.R.; Bercoff, P.G.

2004-01-01

The magnetization reversal of partially exchange-coupled particles is studied in detail. The starting point is the observation of a complicated phenomenology in the irreversible susceptibility and FORC distribution functions of Ba hexaferrite samples obtained by means of different sintering conditions. Several peaks in the first-order reversal curve (FORC) distribution functions were identified and associated with clusters with different number of particles. The switching fields of these clusters were related to an effective anisotropy constant Keff that depends on the number of particles in the cluster. Keff is linked to the exchange-coupled volume between two neighboring particles and as a weighted mean between the anisotropy constants of the coupled and uncoupled volumes. By using the modified Brown's equation αex=0.322 is obtained.In order to interpret these results, the switching field of a two-particle system with partial exchange coupling is studied. It is assumed that the spins reorientation across the contact plane between the particles is like a Bloch wall. The energy of the system is written in terms of the fraction of volume affected by exchange coupling and the switching fields for both particles are calculated. At small interaction volume fraction each particle inverts its magnetization independently from the other. As the fraction of exchange-coupled volume increases, cooperative effects appear and the two particles invert their magnetization in a cooperative way.The proposed model allows to interpret for the first time the empirical factor αex in terms of physical arguments and also explain the details observed in the FORC distribution function

Ion-exchange concentration of inorganic anions from aqueous solution

Directory of Open Access Journals (Sweden)

L. P. Bondareva

2016-01-01

Full Text Available Monitoring of natural waters in the present time - consuming process, the accuracy of which is influenced by many factors: the composition of water, the presence of impurities and "interfering" components. The water sample preparation process includes the step of concentration and separation of ions determined. The most versatile, efficient, and frequently used method is the concentration of inorganic anions from aqueous solutions by ion exchanger, which can optimize the composition of water to the optimal for identification and quantitative determination of anions. The characteristics of sorption chloride, nitrate and sulfate ions of basic anion exchange resin AВ-17 and Purolite A430 were compared in the article. The constants of protolysis of ion exchangers both AB 17 and Purolite A430 are the same and equal 0.037 ± 0,002. The value of total capacity (POE Purolite A430 was 4.3 mmol/g, AB 17 – 3.4 mmol/g. The studied ion exchangers have the same type of ionic groups – quaternary ammonium, but their number and denotes differ. The number of quaternary ammonium groups is higher in Purolite A430, respectively the number of absorbed anions of these ion exchanger is higher. The values of dynamic exchange capacity (DOE of ion exchanger Purolite A430 is higher than these values of AB-17 and equal to 1.48 ± 0.03 mmol / dm3 for chloride ion, 1.50 ± 0.03 mmol / dm3 for nitrate ion, 1.62 ± 0.03 mmol / dm3 for sulfate ion. The values of the POE and DOE of anion-exchange resins Purolite A430 and AV-17 and the characteristics of the individual sorption of chloride, nitrate, sulfate ions showed an advantage of the Purolite for the concentrationing of anions. It is found that times of anions sorption from triple-anion solutions by Purolite A430 are significantly different for different anions, and these times are close for anion-exchanger AV-17. It proves the possibility of quantitative separation and concentration by anion-exchanger Purolite A430.

Investigation on copper alloy and titanium heat exchanger tubes behaviour in sea water service

International Nuclear Information System (INIS)

Casarini, G.; Bianchi, M.; Winkler, L.; Caspani, M.

1982-01-01

Because of the contradictory behaviour in service of some copper alloys used in heat exchangers cooled by sea water (Mediterranean Sea - North Africa), a comparative study on the behaviour of some tubular test samples was performed by means of accelerated test run ''in situ'' using two little heat exchangers supplied by Foster Wheeler Italiana. The aim of the investigation was to obtain quick and reliable information on optimizing the choise of the most suitable material for the construction of new heat exchangers

Fabrication of a novel hydrophobic/ion-exchange mixed-mode adsorbent for the dispersive solid-phase extraction of chlorophenols from environmental water samples.

Science.gov (United States)

Gao, Li; Wei, Yinmao

2016-08-01

A novel mixed-mode adsorbent was prepared by functionalizing silica with tris(2-aminoethyl)amine and 3-phenoxybenzaldehyde as the main mixed-mode scaffold due to the presence of the plentiful amino groups and benzene rings in their molecules. The adsorption mechanism was probed with acidic, natural and basic compounds, and the mixed hydrophobic and ion-exchange interactions were found to be responsible for the adsorption of analytes. The suitability of dispersive solid-phase extraction was demonstrated in the determination of chlorophenols in environmental water. Several parameters, including sample pH, desorption solvent, ionic strength, adsorbent dose, and extraction time were optimized. Under the optimal extraction conditions, the proposed dispersive solid-phase extraction coupled with high-performance liquid chromatography showed good linearity range and acceptable limits of detection (0.22∽0.54 ng/mL) for five chlorophenols. Notably, the higher extraction recoveries (88.7∽109.7%) for five chlorophenols were obtained with smaller adsorbent dose (10 mg) and shorter extraction time (15 min) compared with the reported methods. The proposed method might be potentially applied in the determination of trace chlorophenols in real water samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Leaching studies on ion exchange resins immobilized in bitument matrix

International Nuclear Information System (INIS)

Grosche Filho, C.E.; Chandra, U.; Villalobos, J.P.

1987-01-01

To study radionuclide leaching from bitumen waste forms, many samples of bitumen mixed with ion-exchange resin labelled with 134 Cs were prepared. The resins used in the tests were nuclear grade mixed cationic/anionic bead resins. Different bittumen types were assayed: two destilled and to oxidized bitumens. Laboratory to scale samples, with surface/volume ratio (S/V) = 1, were molded to 5 cm diameter and 10 cm height. The composition of the mixtures were: 30, 40, 50 and 60% by weight of dried resin with bitumen. The leachant was deionized water with a leachant volume to sample surface rario of about 8 cm. Leached fractions were collected according to the recommendation of ISO method, with complete exchange of leachant beckers after each sampling. The volume collected for analysis was one liter. Marinelli were used for counting in a Ge(Li) detector. Up to now, results of 250 days have been accumulated. Samples prepared with distilled bitumen have shown a diffusion coefficient of the order of 10 -14 cm 2 /sec and those prepared with oxidized bitumen yielded a diffusion coefficient of the order of 10 -12 cm 2 /sec. Mathematical models of transport phenomena applied to cylindrical geometry were employed to fit experimental data. (Author) [pt

How did China's foreign exchange reform affect the efficiency of foreign exchange market?

Science.gov (United States)

Ning, Ye; Wang, Yiming; Su, Chi-wei

2017-10-01

This study compares the market efficiency of China's onshore and offshore foreign exchange markets before and after the foreign exchange reform on August 11, 2015. We use the multifractal detrended fluctuation analysis of the onshore and offshore RMB/USD spot exchange rate series as basis. We then find that the onshore foreign exchange market before the reform has the lowest market efficiency, which increased after the reform. The offshore foreign exchange market before the reform has the highest market efficiency, which dropped after the reform. This finding implies the increased efficiency of the onshore foreign exchange market and the loss of efficiency in the offshore foreign exchange market. We also find that the offshore foreign exchange market is more efficient than the onshore market and that the gap shrank after the reform. Changes in intervention of the People's Bank of China since the reform is a possible explanation for the changes in the efficiency of the foreign exchange market.

Exchange coupling in hybrid anisotropy magnetic multilayers quantified by vector magnetometry

Energy Technology Data Exchange (ETDEWEB)

Morrison, C., E-mail: C.Morrison.2@warwick.ac.uk; Miles, J. J.; Thomson, T. [School of Computer Science, University of Manchester, Manchester M13 9PL (United Kingdom); Anh Nguyen, T. N. [Materials Physics, School of ICT, KTH Royal Institute of Technology, Electrum 229, 164 40 Kista (Sweden); Spintronics Research Group, Laboratory for Nanotechnology (LNT), VNU-HCM, Ho Chi Minh City (Viet Nam); Fang, Y.; Dumas, R. K. [Department of Physics, University of Gothenburg, 412 96 Gothenburg (Sweden); Åkerman, J. [Materials Physics, School of ICT, KTH Royal Institute of Technology, Electrum 229, 164 40 Kista (Sweden); Department of Physics, University of Gothenburg, 412 96 Gothenburg (Sweden)

2015-05-07

Hybrid anisotropy thin film heterostructures, where layers with perpendicular and in-plane anisotropy are separated by a thin spacer, are novel materials for zero/low field spin torque oscillators and bit patterned media. Here, we report on magnetization reversal and exchange coupling in a archetypal Co/Pd (perpendicular)-NiFe (in-plane) hybrid anisotropy system studied using vector vibrating sample magnetometry. This technique allows us to quantify the magnetization reversal in each individual magnetic layer, and measure of the interlayer exchange as a function of non-magnetic spacer thickness. At large (>1 nm) spacer thicknesses Ruderman-Kittel-Kasuya-Yosida-like exchange dominates, with orange-peel coupling providing a significant contribution only for sub-nm spacer thickness.

Rare events via multiple reaction channels sampled by path replica exchange

NARCIS (Netherlands)

Bolhuis, P.G.

2008-01-01

Transition path sampling (TPS) was developed for studying activated processes in complex systems with unknown reaction coordinate. Transition interface sampling (TIS) allows efficient evaluation of the rate constants. However, when the transition can occur via more than one reaction channel

Investigating the effects of liquidity and exchange rate on Tehran Stock Exchange

Directory of Open Access Journals (Sweden)

Younos Vakil Alroaia

2014-08-01

Full Text Available This paper presents an empirical investigation to study the effects of two macroeconomic factors; namely exchange rate and liquidity on stock index. The proposed study was applied in Iran and on major index of Tehran Stock Exchange over the period 2001-2011. They reported that the currency exchange maintained negative impact on stock exchange for the period of investigation. This is due to the fact that when currency devalued, working capital decreases and firms did not enough money to purchase raw materials, pay wages, etc. In addition, liquidity marinated a direct and positive relationship with exchange index. However, the impact of liquidity seems to be bigger than currency exchange.

Exchange rate regimes and macroeconomic instabilities in Sub-Saharan Africa

Directory of Open Access Journals (Sweden)

Yaya Camara Seydou

2015-01-01

Full Text Available This article addresses macroeconomic instabilities according to exchange rate regimes in Sub-Saharan Africa (SSA. Based on International Monetary Fund's exchange rate regimes de facto classification, the global sample, SSA, is first divided into two subsamples, which are countries within CFA franc zone (ZCFA and those outside CFA franc zone (HZCFA, and then into four categories, which are the Western Economic and Monetary Union (WAEMU, the Central African Economic and Monetary Community, the countries CFA franc zone with fix exchange rate regimes(HZCFA-FIX, and the countries outside CFA franc zone with flexible exchange rate regimes(HZCFA-FLEX. By applying advanced statistical and econometric methods upon internal and external macroeconomic equilibrium conditions, we show that the inflation, the GDP (or the output and the real exchange rate (RER are very volatile in SSA. However, we found out that they are more volatile in the group HZCFA comparatively to the group ZCFA. We also found out that they are higher in the group HZCFA-FIX than the group HZCFA-FLEX. Moreover, we found out that a high instability of the inflation is combined with those of the output and the RER.

Theory and design of heat exchanger : air cooled plate, spiral heat exchanger

International Nuclear Information System (INIS)

Min, Ui Dong

1960-02-01

This book deals with air cooled heat exchanger, which introduces heat rejection system, wet surface cooler in new from, explanation of structure and design, materials, basic design like plenums chambers and fan ring, finned tube fouling factor, airflow in forced draft and fan design. It also tells of plate heat exchanger and spiral heat exchanger giving descriptions of summary, selection, basic design, device and safety function, maintenance, structure of plate heat exchanger, frames and connector plate and, basic things of spiral tube heat exchanger.

Feasibility study on development of plate-type heat exchanger for BWR plants

International Nuclear Information System (INIS)

Ohyama, Nobuhiro; Suda, Kenichi; Ogata, Hiroshi; Matsuda, Shinichi; Nagasaka, Kazuhiro; Fujii, Toshi; Nozawa, Toshiya; Ishihama, Kiyoshi; Higuchi, Tomokazu

2004-01-01

In order to apply plate-type heat exchanger to RCW, TCW and FPC system in BWR plants, heat test and seismic test of RCW system heat exchanger sample were carried out. The results of these tests showed new design plate-type heat exchanger satisfied the fixed pressure resistance and seismic resistance and keep the function. The evaluation method of seismic design was constructed and confirmed by the results of tests. As anti-adhesion measure of marine organism, an ozone-water circulation method, chemical-feed method and combination of circulation of hot water and air bubbling are useful in place of the chlorine feeding method. Application of the plate-type heat exchanger to BWR plant is confirmed by these investigations. The basic principles, structure, characteristics, application limit and reliability are stated. (S.Y.)

Polyethylene (PE) based proton exchange membrane for use in fuel cell

International Nuclear Information System (INIS)

Moraes, Gilberto de Oliveira

2008-01-01

The irradiation - induced graft of styrene onto polyethylene (PE) in a Cobalt-60 source was carried out using direct (simultaneous) and indirect (preirradiation and peroxidation) methods at room temperature. The dose applied in both cases varied from 0,5 to 80 kGy; In the direct method, the films were immersed in a solution of styrene: methanol (30:70 v/v) and 30% of sulfuric acid(additive) in glass ampoules of 40 ml under inert atmosphere, and then irradiated. After irradiation process, the samples were kept in solution for 8 hours and taken off the ampoules, dried in oven at 60 deg C for another 8 hour period until constant weight. In pre-irradiation method, the samples were irradiated in dry and sealed ampoules, under inert atmosphere. The solution was then added to the samples, and after 8 hours, taken off, dried, sealed and weighted. In peroxidation method, the difference was not inert atmosphere but atmosphere of air (0 2 ).For each samples it was calculated the degree of grafting (DOG). The samples that showed some DOG were sulfonated, characterized (DSC, TGA and infrared) and the ion exchange capacity (IEC) was calculated. The samples processed by indirect method presented no DOG at all. The samples processed by direct method present grafting (best result was 80 kGy). These samples, after sulfonated, presented ion exchange properties. (author)

Reactor fuel exchanging facility

International Nuclear Information System (INIS)

Kubota, Shin-ichi.

1981-01-01

Purpose: To enable operation of an emergency manual operating mechanism for a fuel exchanger with all operatorless trucks and remote operation of a manipulator even if the exchanger fails during the fuel exchanging operation. Constitution: When a fuel exchanging system fails while connected to a pressure tube of a nuclear reactor during a fuel exchanging operation, a stand-by self-travelling truck automatically runs along a guide line to the position corresponding to the stopping position at that time of the fuel exchanger based on a command from a central control chamber. At this time the truck is switched to manual operation, and approaches the exchanger while being monitored through a television camera and then stops. Then, a manipurator is connected to the emergency manual operating mechanism of the exchanger, and is operated through necessary emergency steps by driving the snout, the magazine, the grab or the like in the exchanger in response to the problem, and necessary operations for the emergency treatment are thus performed. (Sekiya, K.)

Alarming of exchange rate crisis: A risk management approach

Directory of Open Access Journals (Sweden)

Da Zhao

2016-05-01

Full Text Available Recently, with increasing volatility of foreign exchange rate, risk management becomes more and more important not only for multinational companies and individuals but also for central governments. This paper attempts to build an econometrics model so as to forecast and manage risks in foreign exchange market, especially during the eve of turbulent periods. By following McNeil and Frey’s (2000 two stage approach called conditional EVT to estimate dynamic VaR commonly used in stock and insurance markets, we extend it by applying a more general asymmetric ARMA-GARCH model to analyze daily foreign exchange dollar-denominated trading data from four countries of different development levels across Asia and Europe for a period of more than 10 years from January 03, 2005 to May 29, 2015, which is certainly representative of global markets. Conventionally, different kinds of backtesting methods are implemented ultimately to evaluate how well the model behaves. Inspiringly, test results show that by taking several specific characteristics (including fat-tails, asymmetry and long-range dependence of the foreign exchange market return data into consideration, the violation ratio of out-of-sample data can be forecasted very well for both fixed and flexible foreign exchange regimes. Moreover, all of the violations are evenly distributed along the whole period which indicates another favorable property of our model. Meanwhile, we find evidence of asymmetry volatility in all of the studied foreign exchange markets even though the magnitudes of the most of them are weak

Theory and design of heat exchanger : Double pipe and heat exchanger in abnormal condition

International Nuclear Information System (INIS)

Min, Ui Dong

1996-02-01

This book introduces theory and design of heat exchanger, which includes HTRI program, multiple tube heat exchanger external heating, theory of heat transfer, basis of design of heat exchanger, two-phase flow, condensation, boiling, material of heat exchanger, double pipe heat exchanger like hand calculation, heat exchanger in abnormal condition such as Jackets Vessel, and Coiled Vessel, design and summary of steam tracing.

Radioanalytical determination of plutonium and americium using ion exchange and extraction chromatography technique in urine

International Nuclear Information System (INIS)

Santhanakrishnan, V.; Sreedevi, K.R.; Rajaram, S.; Ravi, P.M.

2011-01-01

The use of anion exchange chromatography for the separation of Pu and extraction chromatography technique for the separation of Am from urine samples was studied. In the earlier method, Pu separation was carried out by anion exchange chromatography followed by Am separation by cation exchange chromatography. The chemical recovery of Am obtained by cation exchange separation method was inconsistent and low in the range 30-70%. In this study, the average Pu recovery obtained using anion exchange chromatography was 89.2 with standard deviation of 10.4 and the average Am recovery obtained using extraction chromatography with TRU resin was 77.4 with standard deviation of 14.8. Moreover, Am separation could be completed within three hours using the TRU column compared to two days that were required for the cation exchange chromatography. (author)

The Metaphysics of Economic Exchanges

Directory of Open Access Journals (Sweden)

Massin Olivier

2017-05-01

Full Text Available What are economic exchanges? The received view has it that exchanges are mutual transfers of goods motivated by inverse valuations thereof. As a corollary, the standard approach treats exchanges of services as a subspecies of exchanges of goods. We raise two objections against this standard approach. First, it is incomplete, as it fails to take into account, among other things, the offers and acceptances that lie at the core of even the simplest cases of exchanges. Second, it ultimately fails to generalize to exchanges of services, in which neither inverse preferences nor mutual transfers hold true. We propose an alternative definition of exchanges, which treats exchanges of goods as a special case of exchanges of services and which builds in offers and acceptances. According to this theory: (i The valuations motivating exchanges are propositional and convergent rather than objectual and inverse; (ii All exchanges of goods involve exchanges of services/actions, but not the reverse; (iii Offers and acceptances, together with the contractual obligations and claims they bring about, lie at the heart of all cases of exchange.

Method for in situ determination cation exchange capacities of subsurface formations

International Nuclear Information System (INIS)

Fertl, W.H.; Welker, D.W.

1980-01-01

A method is disclosed for the in situ examination of each subsurface formation penetrated by a borehole to ascertain the cation exchange capacity of such formations within a geological region. Natural γ ray logging is used to develop signals functionally related to the total γ radiation and to the potassium-40, uranium and thorium energy-band radiations. A first borehole is traversed by a potential γ ray spectrometer to provide selected measurements of natural γ radiation. Core samples are taken from the logged formation and laboratory tests performed to determine the cation exchange capacity thereof. The cation exchange capacities thus are developed then correlated with selected parameters provided by the γ ray spectrometer to establish functional relationships. Cation exchange capacities of formations in subsequent boreholes within the region are then determined in situ by use of the natural γ ray spectrometer and these established relationships. (author)

The evolutionary synchronization of the exchange rate system in ASEAN+6

Science.gov (United States)

Feng, Xiaobing; Hu, Haibo; Wang, Xiaofan

2010-12-01

Although there are extensive researches on the behavior of the world currency network, the complexity of the Asian regional currency system is not well understood regardless of its importance. Using daily exchange rates this paper examines exchange rate co-movements in the region before and after the China exchange rate reform. It was found that the correlation between Asian currencies and the US Dollar, the previous regional key currency has become weaker and intra-Asia interactions have increased. Cross sample entropy and cross entropy approaches are also applied to examine the synchrony behavior among the Asian currencies. The study also shows that the Asian exchange rate markets featured are neither stochastic nor efficient. These findings may shed some light on the in-depth understanding of collective behaviors in a regional currency network; they will also lay a theoretical foundation for further policy formulation in Asian currency integration.

Marriage exchanges, seed exchanges, and the dynamics of manioc diversity.

Science.gov (United States)

Delêtre, Marc; McKey, Doyle B; Hodkinson, Trevor R

2011-11-08

The conservation of crop genetic resources requires understanding the different variables-cultural, social, and economic-that impinge on crop diversity. In small-scale farming systems, seed exchanges represent a key mechanism in the dynamics of crop genetic diversity, and analyzing the rules that structure social networks of seed exchange between farmer communities can help decipher patterns of crop genetic diversity. Using a combination of ethnobotanical and molecular genetic approaches, we investigated the relationships between regional patterns of manioc genetic diversity in Gabon and local networks of seed exchange. Spatially explicit Bayesian clustering methods showed that geographical discontinuities of manioc genetic diversity mirror major ethnolinguistic boundaries, with a southern matrilineal domain characterized by high levels of varietal diversity and a northern patrilineal domain characterized by low varietal diversity. Borrowing concepts from anthropology--kinship, bridewealth, and filiation--we analyzed the relationships between marriage exchanges and seed exchange networks in patrilineal and matrilineal societies. We demonstrate that, by defining marriage prohibitions, kinship systems structure social networks of exchange between farmer communities and influence the movement of seeds in metapopulations, shaping crop diversity at local and regional levels.

Investigation of the resistance of some naturally occurring and synthetic inorganic ion exchangers against gamma radiation

International Nuclear Information System (INIS)

Nilchi, A.; Khanchi, A.; Ghanadi Maragheh, M.; Bagheri, A.

2003-01-01

The effect of various doses of gamma radiation on the ion-exchange capacity, distribution coefficient values, elution behaviour, physical effect, pH titration and infrared spectra of some synthetic inorganic ion exchangers, namely the cerium substituted phosphates; and naturally occurring inorganic ion exchangers, zeolites from different parts of Iran, have been studied systematically. No significant change has been observed in the ion-exchange capacity (with the exception of CeP(Na), CeP(Di·Na) and zeolite 5 (deposits of arababad talas)), elution behaviour, physical effect, chemical stability and the infrared spectra of the synthetic ion exchangers irradiated up to a total dose of 200 kGy, while a change has been observed in the pH-titration and distribution behaviour. The increase in pH is sharper for irradiated samples with divalent cations than for the normal samples. Furthermore, the K d values, and hence the selectivity towards certain cations increase with the total dose absorbed, reaching its optimum selectivity with the dose of 50-100 kGy. The natural zeolites chosen for these studies, show, similar pattern to those of synthetic ion exchangers, and in some cases an extremely high selectivity toward certain cations, like Be II . These make, zeolites, which are naturally occurring ion exchangers more viable economically, and extremely useful alternative in this industry

Generalized species sampling priors with latent Beta reinforcements

Science.gov (United States)

Airoldi, Edoardo M.; Costa, Thiago; Bassetti, Federico; Leisen, Fabrizio; Guindani, Michele

2014-01-01

Many popular Bayesian nonparametric priors can be characterized in terms of exchangeable species sampling sequences. However, in some applications, exchangeability may not be appropriate. We introduce a novel and probabilistically coherent family of non-exchangeable species sampling sequences characterized by a tractable predictive probability function with weights driven by a sequence of independent Beta random variables. We compare their theoretical clustering properties with those of the Dirichlet Process and the two parameters Poisson-Dirichlet process. The proposed construction provides a complete characterization of the joint process, differently from existing work. We then propose the use of such process as prior distribution in a hierarchical Bayes modeling framework, and we describe a Markov Chain Monte Carlo sampler for posterior inference. We evaluate the performance of the prior and the robustness of the resulting inference in a simulation study, providing a comparison with popular Dirichlet Processes mixtures and Hidden Markov Models. Finally, we develop an application to the detection of chromosomal aberrations in breast cancer by leveraging array CGH data. PMID:25870462

Radiotracer study of phosphate exchange between whey and casein micelles in cow's milk

International Nuclear Information System (INIS)

Kolar, Z.I.; Verburg, T.G.; Dijk, H.J.M. van

1998-01-01

Radiotracer method has been applied to study exchange of calcium ions between the whey calcium salts and micellar calcium phosphate (MCP). The present paper deals with a similar study pertaining to phosphate ions. 32 P-labelled Na 2 HPO 4 was used as the radiotracer for inorganic phosphates of milk. After addition of the radiotracer to skimmed-milk, samples were taken regularly for 700 hours. In the samples casein micelles were separated from whey by ultracentrifugation and finally the radiotracer quantity i.e. 32 P-concentration in the whey samples was measured using a Liquid Scintillation Counter. Compartmental analysis and modelling were used to evaluate the thus obtained time curves for radiotracer quantity in whey. This analysis revealed the presence of three phosphate compartments i.e. exchangeable phosphate entities; one being the whey phosphate. The other two are associated with the exchangeable phosphates of MCP. The mean residence times of phosphate in the latter two compartment differ considerably pointing at two distinctly different embeddings of phosphate groups in the structure of the micellar calcium phosphate of the cow's milk casein. The obtained results are in fair agreement with the mentioned model of MCP

Study of kinetics, equilibrium and isotope exchange in ion exchange systems Pt. 6

International Nuclear Information System (INIS)

Plicka, J.; Stamberg, K.; Cabicar, J.; Gosman, A.

1986-01-01

The description of kinetics of ion exchange in ternary system was based upon three Nernst-Planck equations, each of them describing the particle diffusion flux of a given counterion as an independent process. For experimental verification, the strongly acidic cation exchanger OSTION KS 08 the shallow-bed technique, and 0.2 mol x dm -3 aqueous nitrate solutions were chosen. The kinetics of ion exchange in the system of cations Na + - Mg 2+ - UO 2 2+ was studied. The values of diffusion coefficients obtained by evaluating of kinetics of isotope exchange and binary ion exchange were used for calculation. The comparison of calculated exchange rate curves with the experimental ones was made. It was found that the exchanging counterions were affected by each other. (author)

Quantification of exchangeable and non-exchangeable organically bound tritium (OBT) in vegetation

International Nuclear Information System (INIS)

Kim, S.B.; Korolevych, V.

2013-01-01

The objective of this study is to quantify the relative amounts of exchangeable organically bound tritium (OBT) and non-exchangeable OBT in various vegetables. A garden plot at Perch Lake, where tritium levels are slightly elevated due to releases of tritium from a nearby nuclear waste management area and Chalk River Laboratories (CRL) operations, was used to cultivate a variety of vegetables. Five different kinds of vegetables (lettuce, cabbage, tomato, radish and beet) were studied. Exchangeable OBT behaves like tritium in tissue free water in living organisms and, based on past measurements, accounts for about 20% of the total tritium in dehydrated organic materials. In this study, the percentage of the exchangeable OBT was determined to range from 20% to 57% and was found to depend on the type of vegetables as well as the sequence of the plants exposure to HTO. -- Highlights: ► This study was to quantify the amount of exchangeable OBT compared to non-exchangeable OBT in vegetables. ► The percentage of exchangeable OBT varied between vegetable types and HTO exposure conditions. ► Exchangeable OBT varied from 20 to 36% in un-treated vegetables and from 30 to 57% in treated vegetables

Horizontal Curve Virtual Peer Exchange : an RSPCB Peer Exchange

Science.gov (United States)

2014-06-01

This report summarizes the Horizontal Curve Virtual Peer Exchange sponsored by the Federal Highway Administration (FHWA) Office of Safetys Roadway Safety Professional Capacity Building Program on June 17, 2014. This virtual peer exchange was the f...

Interest Rate Rules, Exchange Market Pressure, and Successful Exchange Rate Management

NARCIS (Netherlands)

Klaassen, F.; Mavromatis, K.

2016-01-01

Central banks with an exchange rate objective set the interest rate in response to what they call ''pressure.'' Instead, existing interest rate rules rely on the exchange rate minus its target. To stay closer to actual policy, we introduce a rule that uses exchange market pressure (EMP), the

Standardizing exchange formats

International Nuclear Information System (INIS)

Lemmel, H.D.; Schmidt, J.J.

1992-01-01

An international network of co-operating data centres is described who maintain identical data bases which are simultaneously updated by an agreed data exchange procedure. The agreement covers ''data exchange formats'' which are compatible to the centres' internal data storage and retrieval systems which remain different, optimized at each centre to the available computer facilities and to the needs of the data users. Essential condition for the data exchange is an agreement on common procedures for the data exchange is an agreement on common procedures for the data compilation, including critical data analysis and validation. The systems described (''EXFOR'', ''ENDF'', ''CINDA'') are used for ''nuclear reaction data'', but the principles used for data compilation and exchange should be valid also for other data types. (author). 24 refs, 4 figs

The Role of Private Information in Short-term Fluctuations of Won/Dollar Exchange Rates

Directory of Open Access Journals (Sweden)

Haesik Park

1999-12-01

Full Text Available In this paper, we have examined the short-run movement of the won/dollar exchange rate using information obtained from the inter-bank market in Korea. First, we constructed the hourly measure of excess demand for dollar and used it as a proxy for the trading pattern of market participants. To construct this time series, we relied on the bid and ask won/dollar exchange rates collected on the two-minute interval. We then estimated the structural VAR model consisting of the actually observed won/dollar exchange rate and the proxied trading pattern of market participants to see if private information, as opposed to public information, is relevant for explaining the hourly movement of the won/dollar exchange rate. Private information is found to account for more 30% of hourly variations of the won/dollar exchange rate. Next, we constructed the trading pattern of market participants on a daily basis using the same data set employed to build the hourly measure. We then examined whether private information is useful for predicting the daily won/dollar exchange rate movement. We found that the forecast model using both private and public information reduces out-of-sample forecast errors of an alternative model relying only on public information by 20~25%. Also, the out-of-sample forecast of the model using both private and public information is found to be more accurate than the random walk model.

Trade balance instability and the optimal exchange rate regime: The case of OPEC countries

Energy Technology Data Exchange (ETDEWEB)

Aljerrah, M.A.

1993-01-01

The OPEC members have experienced wide fluctuations in their trade balances. This can be attributed to several factors: (1) heavy dependence of national income and export earnings on a single primary export-oil; (2) instability of price and world demand for oil; and (3) the exchange rate regime practiced in recent years. An exchange rate policy can be used to minimize the fluctuations in trade balance, given the changes in exchange rates of major international currencies. The purpose of this study is two fold; first, examine the effects of fluctuations in trade balance on the OPEC economies, and second, propose appropriate exchange rate regime for selected OPEC members. The study is divided into two parts. The first part demonstrates the impact of trade balance changes on national income and other macroeconomic variables using a Keynesian framework. The second part involves using conventional trade models to search for the appropriate exchange rate regime to minimize the fluctuations in trade balance of each selective country. The study's findings are: first, fluctuations in trade balances had negative effects on the economics of Algeria, Kuwait, Libya, Saudi Arabia, and the United Arab Emirates. Second, the current exchange rate regime of no sample country is optimal in minimizing trade balance fluctuations. Third, in contrast to expectations, U.S. dollar peg did not stabilize the trade balance of any OPEC member. Finally, the results show that the sample OPEC economies could have enjoyed faster - though with different degree - economic growth if they had pegged their currencies to the derived optimal exchange rate regime. These optimal exchange rate regimes are: the SDR for Algeria and the United Arab Emirates, the purchasing power parity for Libya and Saudi Arabia, and the real Yen for Kuwait.

Enhanced exchange bias in MnN/CoFe bilayers after high-temperature annealing

Science.gov (United States)

Dunz, M.; Schmalhorst, J.; Meinert, M.

2018-05-01

We report an exchange bias of more than 2700 Oe at room temperature in MnN/CoFe bilayers after high-temperature annealing. We studied the dependence of exchange bias on the annealing temperature for different MnN thicknesses in detail and found that samples with tMnN > 32nm show an increase of exchange bias for annealing temperatures higher than TA = 400 °C. Maximum exchange bias values exceeding 2000 Oe with reasonably small coercive fields around 600 Oe are achieved for tMnN = 42, 48 nm. The median blocking temperature of those systems is determined to be 180 °C after initial annealing at TA = 525 °C. X-ray diffraction measurements and Auger depth profiling show that the large increase of exchange bias after high-temperature annealing is accompanied by strong nitrogen diffusion into the Ta buffer layer of the stacks.

Role of Department Heads in Academic Development: A Leader-Member Exchange and Organizational Resource Perspective

Science.gov (United States)

Horne, Andre Leonard; du Plessis, Yvonne; Nkomo, Stella

2016-01-01

This article examines the role of leadership in the development of academic talent in higher education from a social exchange and organizational support perspective. Drawing from a sample of academic staff at a large South African university, the study investigates the extent to which a quality leader-member exchange relationship versus a formal…

Accurate determination of trace amounts of phosphorus in geological samples by inductively coupled plasma atomic emission spectrometry with ion-exchange separation

International Nuclear Information System (INIS)

Asoh, Kazuya; Ebihara, Mitsuru

2013-01-01

Graphical abstract: -- Highlights: •We set up an effective ICP-AES procedure for determining trace P in rock samples. •Some certified values of P for reference rock samples were proved to be doubtful. •Accurate and reliable data were presented for a suite of geological reference rocks. -- Abstract: In order to determine trace amounts of phosphorus in geological and cosmochemical rock samples, simple as well as reliable analytical schemes using an ICP-AES instrument were investigated. A (conventional) ICP-AES procedure could determine phosphorus contents at the level of several 100 μg g −1 with a reasonable reproducibility ( −1 ; 1σ). An ICP-AES procedure coupled with matrix-separation using cation and anion exchange resins could lower the quantification level down to 1 μg g −1 or even lower under the present experimental conditions. The matrix-separation ICP-AES procedure developed in this study was applied to twenty-one geological reference samples issued by Geological Survey of Japan. Obtained values vary from 1250 μg g −1 for JB-3 (basalt) to 2.07 μg g −1 for JCt-1 (carbonate). Matrix-separation ICP-AES yielded reasonable reproducibility (less than 8.3%; 1σ) of three replicate analyses for all the samples analyzed. In comparison of our data with certificate values as well as literature or reported values, there appear to be an apparent (and large) discrepancy between our values and certificate/reported values regardless of phosphorus contents. Based on the reproducibility of our data and the analytical capability of the matrix-separation ICP-AES procedure developed in this study (in terms of quantification limit, recovery, selectivity of an analyte through pre-concentration process, etc.), it is concluded that certified values for several reference standard rocks should be reevaluated and revised accordingly. It may be further pointed that some phosphorus data reported in literatures should be critically evaluated when they are to be

Magnetic stability in exchange-spring and exchange bias systems after multiple switching cycles.

Energy Technology Data Exchange (ETDEWEB)

Jiang, J. S.; Inomata, A.; You, C.-Y.; Pearson, J. E.; Bader, S. D.

2001-06-01

We have studied the magnetic stability in exchange bias and exchange spring systems prepared via epitaxial sputter deposition. The two interfacial exchange coupled systems, Fe/Cr(211) double superlattices consisting of a ferromagnetic and an antiferromagnetic Fe/Cr superlattice that are exchange coupled through a Cr spacer, and Sin-Co/Fe exchange-spring bilayer structures with ferromagnetically coupled hard Sin-Co layer and soft Fe layer, were epitaxially grown on suitably prepared Cr buffer layers to give rise to different microstructure and magnetic anisotropy. The magnetic stability was investigated using the magneto-optic Kerr effect during repeated reversal of the soft layer magnetization by field cycling up to 10{sup 7} times. For uniaxial Fe/Cr exchange biased double superlattices and exchange spring bilayers with uniaxial Sin-Co, small but rapid initial decay in the exchange bias field HE and in the remanent magnetization is observed. However, the exchange spring bilayers with biaxial and random in-plane anisotropy in the Sin-Co layer shows gradual decay in H{sub E} and without large reduction of the magnetization. The different decay behaviors are attributed to the different microstructure and spin configuration of the pinning layers.

Ultrafiltration Membrane Fouling and the Effect of Ion Exchange Resins

KAUST Repository

Jamaly, Sanaa

2011-12-01

Membrane fouling is a challenging process for the ultrafiltration membrane during wastewater treatment. This research paper determines the organic character of foulants of different kinds of wastewater before and after adding some ion exchange resins. Two advanced organic characterization methods are compared in terms of concentration of dissolved organic carbons: The liquid chromatography with organic carbon (LC-OCD) and Shimadzu total organic carbon (TOC). In this study, two secondary wastewater effluents were treated using ultrafiltration membrane. To reduce fouling, pretreatment using some adsorbents were used in the study. Six ion exchange resins out of twenty were chosen to compare the effect of adsorbents on fouling membrane. Based on the percent of dissolved organic carbon’s removal, three adsorbents were determined to be the most efficient (DOWEX Marathon 11 anion exchange resin, DOWEX Optipore SD2 polymeric adsorbent, and DOWEX PSR2 anion exchange), and three other ones were determined to the least efficient (DOWEX Marathon A2 anion exchange resin, DOWEX SAR anion exchange resin, and DOWEX Optipore L493 polymeric adsorbent). Organic characterization for feed, permeate, and backwash samples were tested using LC-OCD and TOC to better understand the characteristics of foulants to prevent ultrafiltration membrane fouling. The results suggested that the polymeric ion exchange resin, DOWEX SD2, reduced fouling potential for both treated wastewaters. All the six ion exchange resins removed more humic fraction than other organic fractions in different percent, so this fraction is not the main for cause for UF membrane fouling. The fouling of colloids was tested before and after adding calcium. There is a severe fouling after adding Ca2+ to effluent colloids.

The effects of real exchange rate misalignment and real exchange volatility on exports

OpenAIRE

Diallo, Ibrahima Amadou

2011-01-01

This paper uses panel data cointegration techniques to study the impacts of real exchange rate misalignment and real exchange rate volatility on total exports for a panel of 42 developing countries from 1975 to 2004. The results show that both real exchange rate misalignment and real exchange rate volatility affect negatively exports. The results also illustrate that real exchange rate volatility is more harmful to exports than misalignment. These outcomes are corroborated by estimations on s...

Impulse Response of the Exchange Rate Volatility to a Foreign Exchange Intervention Shock

OpenAIRE

Hoshikawa, Takeshi

2009-01-01

This paper uses Lin's technique (1997) to report on the impulse response function analysis that traces the dynamics of exchange rate volatility from innovations in Japanese foreign exchange intervention. Using a multivariate GARCH model, we employed a volatility impulse response function based on Lin (1997) to detect the impulse response of exchange rate volatility on a one-unit foreign exchange intervention shock. The main findings of t his paper are as follows: (1) a foreign exchange inter...

Nearly 1000 Protein Identifications from 50 ng of Xenopus laevis Zygote Homogenate Using Online Sample Preparation on a Strong Cation Exchange Monolith Based Microreactor Coupled with Capillary Zone Electrophoresis.

Science.gov (United States)

Zhang, Zhenbin; Sun, Liangliang; Zhu, Guijie; Cox, Olivia F; Huber, Paul W; Dovichi, Norman J

2016-01-05

A sulfonate-silica hybrid strong cation exchange monolith microreactor was synthesized and coupled to a linear polyacrylamide coated capillary for online sample preparation and capillary zone electrophoresis-tandem mass spectrometry (CZE-MS/MS) bottom-up proteomic analysis. The protein sample was loaded onto the microreactor in an acidic buffer. After online reduction, alkylation, and digestion with trypsin, the digests were eluted with 200 mM ammonium bicarbonate at pH 8.2 for CZE-MS/MS analysis using 1 M acetic acid as the background electrolyte. This combination of basic elution and acidic background electrolytes results in both sample stacking and formation of a dynamic pH junction. 369 protein groups and 1274 peptides were identified from 50 ng of Xenopus laevis zygote homogenate, which is comparable with an offline sample preparation method, but the time required for sample preparation was decreased from over 24 h to less than 40 min. Dramatically improved performance was produced by coupling the reactor to a longer separation capillary (∼100 cm) and a Q Exactive HF mass spectrometer. 975 protein groups and 3749 peptides were identified from 50 ng of Xenopus protein using the online sample preparation method.

Exchange Rate Exposure and Its Determinants: A Firm and Industry Analysis of the UK Companies

OpenAIRE

He, Jiao

2010-01-01

This study assesses whether the unexpected exchange rate movements volatilize the UK firms’ stock return based on the firm- and industry-level analysis, and examines whether the magnitude of the exchange rate exposure is determined by the firm-specific factors. Using a sample of 244 UK companies listed in the FTSE 350 during the test period between December 1999 and December 2009, the result documents that the exchange rate fluctuation does affect the firm value. Among the five introduced ex...

Response of a tundra ecosytem to elevated atmospheric carbon dioxide and CO2-induced climate change. Final report

International Nuclear Information System (INIS)

Oechel, W.C.

1996-11-01

The overall objective of this research was to document current patterns of CO 2 flux in selected locations of the circumpolar arctic, and to develop the information necessary to predict how these fluxes may be affected by climate change. In fulfillment of these objectives, net CO 2 flux was measured at several sites on the North Slope of Alaska during the 1990-94 growing season (June-August) to determine the local and regional patterns, of seasonal CO 2 exchange. In addition, net CO 2 flux was measured in the Russian and Icelandic Arctic to determine if the patterns of CO 2 exchange observed in Arctic Alaska were representative of the circumpolar arctic, while cold-season CO 2 flux measurements were carried out during the 1993-94 winter season to determine the magnitude of CO 2 efflux not accounted for by the growing season measurements. Manipulations of soil water table depth and surface temperature, which were identified from the extensive measurements as being the most important variables in determining the magnitude and direction of net CO 2 exchange, were carried out during the 1993-94 growing seasons in tussock and wet sedge tundra ecosystems. Finally, measurements of CH 4 flux were also measured at several of the North Slope study sites during the 1990-91 growing seasons. Measurements were made on small (e.g. 0.5 m 2 ) plots using a portable gas-exchange system and cuvette. The sample design allowed frequent measurements of net CO 2 exchange and respiration over diurnal and seasonal cycles, and a large spatial extent that incorporated both locally and regionally diverse tundra surface types. Measurements both within and between ecosystem types typically extended over soil water table depth and temperature gradients, allowing for the indirect analysis of the effects of anticipated climate change scenarios on net CO 2 exchange. In situ experiments provided a direct means for testing hypotheses

Response of a tundra ecosytem to elevated atmospheric carbon dioxide and CO{sub 2}-induced climate change. Final report

Energy Technology Data Exchange (ETDEWEB)

Oechel, W.C.

1996-11-01

The overall objective of this research was to document current patterns of CO{sub 2} flux in selected locations of the circumpolar arctic, and to develop the information necessary to predict how these fluxes may be affected by climate change. In fulfillment of these objectives, net CO{sub 2} flux was measured at several sites on the North Slope of Alaska during the 1990-94 growing season (June-August) to determine the local and regional patterns, of seasonal CO{sub 2} exchange. In addition, net CO{sub 2} flux was measured in the Russian and Icelandic Arctic to determine if the patterns of CO{sub 2} exchange observed in Arctic Alaska were representative of the circumpolar arctic, while cold-season CO{sub 2} flux measurements were carried out during the 1993-94 winter season to determine the magnitude of CO{sub 2} efflux not accounted for by the growing season measurements. Manipulations of soil water table depth and surface temperature, which were identified from the extensive measurements as being the most important variables in determining the magnitude and direction of net CO{sub 2} exchange, were carried out during the 1993-94 growing seasons in tussock and wet sedge tundra ecosystems. Finally, measurements of CH{sub 4} flux were also measured at several of the North Slope study sites during the 1990-91 growing seasons. Measurements were made on small (e.g. 0.5 m{sup 2}) plots using a portable gas-exchange system and cuvette. The sample design allowed frequent measurements of net CO{sub 2} exchange and respiration over diurnal and seasonal cycles, and a large spatial extent that incorporated both locally and regionally diverse tundra surface types. Measurements both within and between ecosystem types typically extended over soil water table depth and temperature gradients, allowing for the indirect analysis of the effects of anticipated climate change scenarios on net CO{sub 2} exchange. In situ experiments provided a direct means for testing hypotheses.

Spectrophotometric flow injection catalytic determination of molybdenum in plant digest using ion exchange resin

International Nuclear Information System (INIS)

Pessenda, L.C.R.

1987-03-01

A spectrophotometric flow injection analytical method based on the catalytic action of molybdenum on the oxidation of iodide by hydrogen peroxide in acidic medium is proposed for the molybdenum determination in plant digests. A cation exchange resin column is incorporated into a flow injection system for removal of interferents. The following system variables were investigated and optimized: reagent concentrations, sample injection volume, mixing and reaction coil lengths, temperature, sampling time, pumping rate and concentration of eluting agents. The effects of interfering species and of the acidity of samples on the molybdenum retention by the ion exchange resin column were investigated. The proposed method is characterized by good precision (r.s.d. (2.0%), a sampling rate of about 40 samples per hour, and permits the determination of molybdenum in plant digests in the range 1.0 to 40.0 μg/l. The results compare well with those obtained by graphite furnace atomic absorption spectrometry. (author) [pt

Two-dimensional exchange and nutation exchange nuclear quadrupole resonance spectroscopy

International Nuclear Information System (INIS)

Mackowiak, M.; Sinyavsky, N.; Velikite, N.; Nikolaev, D.

2002-01-01

A theoretical treatment of the 2D exchange NQR pulse sequence is presented and applied to a quantitative study of exchange processes in molecular crystals. It takes into account the off-resonance irradiation, which critically influences the spin dynamics. The response to the three-pulse sequence of a system of spins I=3/2 in zero applied field, experiencing electric quadrupole couplings, is analysed. The mixing dynamics by exchange and the expected cross-peak intensities as a function of the frequency offset have been derived. The theory is illustrated by a study of the optimization procedure, which is of crucial importance for the detection of the cross- and diagonal-peaks in a 2D-exchange spectrum. The systems investigated are hexachloroethane and tetrachloroethylene. They show threefold and twofold reorientational jumps about the carbon-carbon axis, respectively. A new method of direct determination of rotational angles based on two-dimensional nutation exchange NQR spectroscopy is proposed. The method involves the detection of exchange processes through NQR nutation spectra recorded after the mixing interval. The response of a system of spins I=3/2 to the three-pulse sequence with increasing pulse widths is analyzed. It is shown that the 2D-nutation exchange NQR spectrum exhibits characteristic ridges, which manifest the motional mechanism in a model-independent fashion. The angles through which the molecule rotates can be read directly from elliptical ridges in the 2D spectrum, which are also sensitive to the asymmetry parameter of the electric field gradient tensor. (orig.)

Phase separation and exchange bias effect in Ca doped EuCrO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Deng, Dongmei, E-mail: dmdeng@shu.edu.cn [Department of Physics and Materials Genome Institute, Shanghai University, Shanghai 200444 (China); Wang, Xingyu; Zheng, Jiashun; Qian, Xiaolong [Department of Physics and Materials Genome Institute, Shanghai University, Shanghai 200444 (China); Yu, Dehong; Sun, Dehui [Bragg Institute, Australian Nuclear Science and Technology Organization, Kirrawee DC, NSW 2232 (Australia); Jing, Chao [Department of Physics and Materials Genome Institute, Shanghai University, Shanghai 200444 (China); Lu, Bo [Analysis and Measurement Center and Laboratory for Microstructures of Shanghai University, Shanghai 200444 (China); Kang, Baojuan; Cao, Shixun; Zhang, Jincang [Department of Physics and Materials Genome Institute, Shanghai University, Shanghai 200444 (China)

2015-12-01

The rare-earth chromites have attracted increasing interests in recent years, as a member of a few single-phase multiferroic materials. We studied the structure and magnetic property of a series of Ca-doped EuCrO{sub 3} samples by using X-ray powder diffraction and Physical Property Measurement System. Phase separation, rotation of magnetization in M(T) curve and exchange bias effect have been identified. The Eu{sub 0.7}Ca{sub 0.3}CrO{sub 3} polycrystalline sample may be intrinsically phase-separated, with Cr{sup 3+}-rich, Cr{sup 4+}-rich canted antiferromagnetic regions surrounded by spin glass-like frustrated phase, resulting in several magnetic features including: (1) a broad and slow increase of M(T) curve with the decrease of temperature; (2) rotation of magnetization with increasing cooling field; (3) exchange bias and glassy magnetism. The rotation of magnetization is ascribed to the rotation of the moment of Cr{sup 4+}-rich regions, arising from the competition between exchange coupling energy and magnetostatic energy. The exchange bias effect suggests the formation of weak ferromagnetic unidirectional anisotropy during field cooling, due to the exchange coupling among weak ferromagnetic domains and surrounding spin glass-like regions. This result helps understanding the interaction among different magnetic domains and phases in a complex system. - Highlights: • Exchange bias effect and glassy magnetism were observed in Eu{sub 0.7}Ca{sub 0.3}CrO{sub 3}. • Rotation of the moments of Cr{sup 4+}-rich regions result in the rotation of magnetization in M(T) curve. • Spin glass-like regions contribute to the observed exchange bias effect.

Why the long hours? Job demands and social exchange dynamics.

Science.gov (United States)

Genin, Emilie; Haines, Victor Y; Pelletier, David; Rousseau, Vincent; Marchand, Alain

2016-11-22

This study investigates the determinants of long working hours from the perspectives of the demand-control model [Karasek, 1979] and social exchange theory [Blau, 1964; Goulder, 1960]. These two theoretical perspectives are tested to understand why individuals work longer (or shorter) hours. The hypotheses are tested with a representative sample of 1,604 employed Canadians. In line with Karasek's model, the results support that high job demands are positively associated with longer work hours. The social exchange perspective would predict a positive association between skill discretion and work hours. This hypothesis was supported for individuals with a higher education degree. Finally, the results support a positive association between active jobs and longer work hours. Our research suggests that job demands and social exchange dynamics need to be considered together in the explanation of longer (or shorter) work hours.

Noninvasive mapping of water diffusional exchange in the human brain using filter-exchange imaging.

Science.gov (United States)

Nilsson, Markus; Lätt, Jimmy; van Westen, Danielle; Brockstedt, Sara; Lasič, Samo; Ståhlberg, Freddy; Topgaard, Daniel

2013-06-01

We present the first in vivo application of the filter-exchange imaging protocol for diffusion MRI. The protocol allows noninvasive mapping of the rate of water exchange between microenvironments with different self-diffusivities, such as the intracellular and extracellular spaces in tissue. Since diffusional water exchange across the cell membrane is a fundamental process in human physiology and pathophysiology, clinically feasible and noninvasive imaging of the water exchange rate would offer new means to diagnose disease and monitor treatment response in conditions such as cancer and edema. The in vivo use of filter-exchange imaging was demonstrated by studying the brain of five healthy volunteers and one intracranial tumor (meningioma). Apparent exchange rates in white matter range from 0.8±0.08 s(-1) in the internal capsule, to 1.6±0.11 s(-1) for frontal white matter, indicating that low values are associated with high myelination. Solid tumor displayed values of up to 2.9±0.8 s(-1). In white matter, the apparent exchange rate values suggest intra-axonal exchange times in the order of seconds, confirming the slow exchange assumption in the analysis of diffusion MRI data. We propose that filter-exchange imaging could be used clinically to map the water exchange rate in pathologies. Filter-exchange imaging may also be valuable for evaluating novel therapies targeting the function of aquaporins. Copyright © 2012 Wiley Periodicals, Inc.

Gendered Pathways: Violent Childhood Maltreatment, Sex Exchange, and Drug Use.

Science.gov (United States)

Verona, Edelyn; Murphy, Brett; Javdani, Shabnam

2015-04-20

Recent work has emphasized the role of violent victimization, along with risky contexts like sex exchange, in pathways to problems of externalizing and substance use in women. Nonetheless, few studies have empirically tested gender differences involving the roles of adversity factors (e.g., childhood violent maltreatment, sex exchange) in drug use patterns. The present study tested a model of gender differences in relationships between childhood physical and sexual abuse, sex exchange, and two indicators of drug use: engagement and symptoms of disorder. We recruited an ethnically-diverse sample of 304 (130 women) adults with recent histories of violence and/or drug use, who completed a substance use diagnostic interview, the Childhood Trauma Questionnaire, and a sex exchange questionnaire. First, structural equation modeling revealed that childhood sexual and physical abuse were related to increased drug engagement in women and men, respectively, above the influence of early childhood contextual variables (e.g., neighborhood, family) and age. Second, sexual abuse was related to sex exchange, which in turn was related to drug use symptoms in women but not men. These data provide empirical support for distinct trauma-related pathways to drug use problems in men and women, which has implications for gendered explanations and prevention approaches.

A novel approach to Ca-Sr separation in the determination of 90Sr using inorganic exchangers

International Nuclear Information System (INIS)

Stella, R.; Pavia Univ.; Valentini, M.T.G.; Maggi, L.

1992-01-01

A procedure for 90 Sr determination in calcium rich samples is presented. It is based on the precipitation of calcium oxalate in homogeneous solution and under controlled conditions to minimize the comprecipitation of strontium. The latter is subsequently separated as carbonate and radiochemical purification is completed by ion exchange chromatography on two inorganic exchangers: PRTD (partially reduced tin dioxide) and CUCR (copper chromate). The procedure was applied to environmental samples such as ashed sediment, fish and vegetable and results are reported. (author) 15 refs.; 2 tabs

Optimization of Heat Exchangers

International Nuclear Information System (INIS)

Catton, Ivan

2010-01-01

The objective of this research is to develop tools to design and optimize heat exchangers (HE) and compact heat exchangers (CHE) for intermediate loop heat transport systems found in the very high temperature reator (VHTR) and other Generation IV designs by addressing heat transfer surface augmentation and conjugate modeling. To optimize heat exchanger, a fast running model must be created that will allow for multiple designs to be compared quickly. To model a heat exchanger, volume averaging theory, VAT, is used. VAT allows for the conservation of mass, momentum and energy to be solved for point by point in a 3 dimensional computer model of a heat exchanger. The end product of this project is a computer code that can predict an optimal configuration for a heat exchanger given only a few constraints (input fluids, size, cost, etc.). As VAT computer code can be used to model characteristics (pumping power, temperatures, and cost) of heat exchangers more quickly than traditional CFD or experiment, optimization of every geometric parameter simultaneously can be made. Using design of experiment, DOE and genetric algorithms, GE, to optimize the results of the computer code will improve heat exchanger design.

A two-particle exchange interaction model

International Nuclear Information System (INIS)

Lyubina, Julia; Mueller, Karl-Hartmut; Wolf, Manfred; Hannemann, Ullrich

2010-01-01

The magnetisation reversal of two interacting particles was investigated within a simple model describing exchange coupling of magnetically uniaxial single-domain particles. Depending on the interaction strength W, the reversal may be cooperative or non-cooperative. A non-collinear reversal mode is obtained even for two particles with parallel easy axes. The model yields different phenomena as observed in spring magnets such as recoil hysteresis in the second quadrant of the field-magnetisation-plane, caused by exchange bias, as well as the mentioned reversal-rotation mode. The Wohlfarth's remanence analysis performed on aggregations of such pairs of interacting particles shows that the deviation δM(H m ) usually being considered as a hallmark of magnetic interaction vanishes for all maximum applied fields H m not only at W=0, but also for sufficiently large values of W. Furthermore, this so-called δM-plot depends on whether the sample is ac-field or thermally demagnetised.

A two-particle exchange interaction model

Energy Technology Data Exchange (ETDEWEB)

Lyubina, Julia, E-mail: j.lyubina@ifw-dresden.d [IFW Dresden, Institute for Metallic Materials, P.O. Box 270016, D-01171 Dresden (Germany); Mueller, Karl-Hartmut; Wolf, Manfred; Hannemann, Ullrich [IFW Dresden, Institute for Metallic Materials, P.O. Box 270016, D-01171 Dresden (Germany)

2010-10-15

The magnetisation reversal of two interacting particles was investigated within a simple model describing exchange coupling of magnetically uniaxial single-domain particles. Depending on the interaction strength W, the reversal may be cooperative or non-cooperative. A non-collinear reversal mode is obtained even for two particles with parallel easy axes. The model yields different phenomena as observed in spring magnets such as recoil hysteresis in the second quadrant of the field-magnetisation-plane, caused by exchange bias, as well as the mentioned reversal-rotation mode. The Wohlfarth's remanence analysis performed on aggregations of such pairs of interacting particles shows that the deviation {delta}M(H{sub m}) usually being considered as a hallmark of magnetic interaction vanishes for all maximum applied fields H{sub m} not only at W=0, but also for sufficiently large values of W. Furthermore, this so-called {delta}M-plot depends on whether the sample is ac-field or thermally demagnetised.

Treatment of carprofen overdose with therapeutic plasma exchange in a dog.

Science.gov (United States)

Kjaergaard, Astrid B; Davis, Jennifer L; Acierno, Mark J

2018-06-13

To report the use of therapeutic plasma exchange (TPE) in a dog with carprofen toxicosis. A 6-year-old female neutered Bichon Frise weighing 6.9 kg was examined after it had ingested 72 mg/kg carprofen. Mild dehydration without azotemia and with a urine specific gravity of 1.050 was noted at presentation. Treatment consisted of induction of emesis, symptomatic medical therapy, and TPE. The TPE achieved 1.5 plasma volume exchanges over 3 hours. Blood samples and effluent samples were collected every 30 minutes during TPE and additional blood samples were collected 11 and 35 hours after treatment. Carprofen concentrations in these samples were determined by high-pressure liquid chromatography. A 51% reduction in serum carprofen concentration was achieved following TPE. This report describes the successful reduction of plasma carprofen concentration in a dog using TPE. Although recent studies suggest that this particular dog may not have received a toxic dose, a 51% reduction of plasma carprofen concentration was achieved over 180 minutes, and TPE may be beneficial for treatment of dogs that have ingested higher doses. © Veterinary Emergency and Critical Care Society 2018.

Foreign exchange transaction exposure of enterprises in Serbia

Directory of Open Access Journals (Sweden)

Bogićević Jasmina

2016-01-01

Full Text Available Enterprises involved in international business face transaction exposure to foreign exchange risk. This type of exposure occurs when an enterprise trades, borrows, or lеnds in foreign currency. Transaction exposure has a direct effect on an enterprise’s financial position and profitability. It is one of the three forms of exposure to exchange rate fluctuations, the other two being translation exposure and operating exposure. The aim of this paper is to assess the transaction exposure of enterprises in Serbia operating internationally. In addition to identifying and measuring transaction exposure, this paper explores the practical importance that enterprises in Serbia attach to management of this type of foreign exchange risk. We do not find significant differences between domestic and foreign enterprises in their choice of the type of foreign exchange risk exposure to manage. Although transaction exposure is the most managed type of foreign exchange risk, research has shown that, compared to foreign businesses, Serbian enterprises do not use sufficient protective measures to minimize the negative impact of this type of exposure on their cash flows and profitability. We expected that there would be a statistically significant dependence between the volume of enterprises’ foreign currency transactions and the level of applied transaction exposure management practices. However, the results of our research, based on a sample of enterprises in Serbia operating internationally, show that transaction exposure management practices can be influenced by factors other than the level of an enterprise’s foreign currency transactions, such as the enterprise’s country of origin.

Ion-Exchange Chromatography: Basic Principles and Application.

Science.gov (United States)

Cummins, Philip M; Rochfort, Keith D; O'Connor, Brendan F

2017-01-01

Ion-Exchange Chromatography (IEC) allows for the separation of ionizable molecules on the basis of differences in charge properties. Its large sample-handling capacity, broad applicability (particularly to proteins and enzymes), moderate cost, powerful resolving ability, and ease of scale-up and automation have led to it becoming one of the most versatile and widely used of all liquid chromatography (LC) techniques. In this chapter, we review the basic principles of IEC, as well as the broader criteria for selecting IEC conditions. By way of further illustration, we outline basic laboratory protocols to partially purify a soluble serine peptidase from bovine whole brain tissue, covering crude tissue extract preparation through to partial purification of the target enzyme using anion-exchange chromatography. Protocols for assaying total protein and enzyme activity in both pre- and post-IEC fractions are also described.

Determination of phosphorus in urban sewage sludge using the isotopic exchange kinetics method

International Nuclear Information System (INIS)

Rojas de Tramontini, Susana; Barbaro, Nestor O.; Lopez, Silvia C.

1999-01-01

The aim of this work was to assess the differences among soil available P, the use by the plants of sludge P, and of a water soluble fertilizer (Ca(H 2 PO 4 ) 2 ) P, using isotopic exchange kinetics methods. The sludge was provided by the Sewage Sludge Treatment Plant of Tucuman City, Argentina. The isotopic exchange kinetics experiment, in which the fate of carrier free 32 PO 4 added to the soil solution at a steady state was studied, gives information on soil P exchangeability. The experiment was carried out in the laboratory, where sewage sludge and water soluble fertilizer were added to soil samples taken at a depth of 0-25 and 25-40 cm. Changes in the soil P isotopically exchangeable within 1 minute measurements in the soil with sludge and in the soil with water soluble fertilizer showed that the 0-25 cm deep soil samples had a low P sorption capacity (r1 /R values were low). The sludge had high total and organic P, but the P in the soil solution was lower than the P provided by the water soluble fertilizer. Therefore, despite its higher total P content, this sludge contained slow available forms of P

Estimating Exchange Rate Exposure over Various Return Horizons: Focusing on Major Countries in East Asia

Directory of Open Access Journals (Sweden)

Jeong Wook Lee

2016-12-01

Full Text Available In this paper, we estimate the exchange rate exposure, indicating the effect of exchange rate movements on firm values, for a sample of 1,400 firms in seven East Asian countries. The exposure estimates based on various exchange rate variables, return horizons and a control variable are compared. A key result from our analysis is that the long term effect of exchange rate movements on firm values is greater than the short term effect. And we find very similar results from using other exchange rate variables such as the U.S. dollar exchange rate, etc. Second, we add exchange rate volatility as a control variable and find that the extent of exposure is not much changed. Third, we examine the changes in exposure to exchange rate volatility with an increase in return horizon. Consequently the ratio of firms with significant exposures increases with the return horizons. Interestingly, the increase of exposure with the return horizons is faster for exposure to volatility than for exposure to exchange rate itself. Taken as a whole, our findings suggest that the so-called "exposure puzzle" may be a matter of the methodology used to measure exposure.

Comparison of inorganic ion exchange materials for removing cesium, strontium, and transuranic elements from K-basin water

International Nuclear Information System (INIS)

Brown, G.N.; Bontha, J.R.; Carson, K.J.; Elovich, R.J.; DesChane, J.R.

1997-10-01

The work presented in this report was conducted by the Pacific Northwest National Laboratory (PNNL) under the Efficient Separations and Crosscutting Program (ESP), Office of Science and Technology, U.S. Department of Energy (DOE). The objective of this work was to investigate radionuclide uptake by several newly produced ion exchange materials under actual waste conditions, and to compare the performance of those materials with that of commercially available ion exchangers. The equilibrium uptake data presented in this report are useful for identifying potential materials that are capable of removing cesium and strontium from 105-KE Basin water. The data show the relative selectivities of the ion exchange materials under similar operating conditions. Additional flow studies are needed to predict material capacities and to develop complete ion exchange process flow sheets. The materials investigated in this study include commercially available ion exchangers such as IONSIV reg-sign IE-911 (manufactured by UOP), clinoptilolite (a naturally occurring zeolite), and materials produced on an experimental basis by AlliedSignal (biotites and nonatitanates), 3M (hexacyanoferrates), Selion Technologies, Inc. (hexacyanoferrates and titanates), and Texas A ampersand M University (pharmacosiderites, biotites, and nonatitanates). In all, the performance of 14 ion exchange materials was evaluated at two solution-to-exchanger mass ratios (i.e., 10 4 and 10 5 ) using actual 105-KE Basin water. Evaluation consisted of determining cesium and strontium batch distribution coefficients, loading, and decontamination factors. Actual 105-KE Basin water was obtained from a sample collected during the sludge dissolution work conducted by PNNL in FY 1996. This sample was taken from the bottom of the basin and contained significantly higher concentrations of the radioactive constituents than do samples taken from the top of the basin

Comparison of inorganic ion exchange materials for removing cesium, strontium, and transuranic elements from K-basin water

Energy Technology Data Exchange (ETDEWEB)

Brown, G.N.; Bontha, J.R.; Carson, K.J.; Elovich, R.J.; DesChane, J.R.

1997-10-01

The work presented in this report was conducted by the Pacific Northwest National Laboratory (PNNL) under the Efficient Separations and Crosscutting Program (ESP), Office of Science and Technology, U.S. Department of Energy (DOE). The objective of this work was to investigate radionuclide uptake by several newly produced ion exchange materials under actual waste conditions, and to compare the performance of those materials with that of commercially available ion exchangers. The equilibrium uptake data presented in this report are useful for identifying potential materials that are capable of removing cesium and strontium from 105-KE Basin water. The data show the relative selectivities of the ion exchange materials under similar operating conditions. Additional flow studies are needed to predict material capacities and to develop complete ion exchange process flow sheets. The materials investigated in this study include commercially available ion exchangers such as IONSIV{reg_sign} IE-911 (manufactured by UOP), clinoptilolite (a naturally occurring zeolite), and materials produced on an experimental basis by AlliedSignal (biotites and nonatitanates), 3M (hexacyanoferrates), Selion Technologies, Inc. (hexacyanoferrates and titanates), and Texas A&M University (pharmacosiderites, biotites, and nonatitanates). In all, the performance of 14 ion exchange materials was evaluated at two solution-to-exchanger mass ratios (i.e., 10{sup 4} and 10{sup 5}) using actual 105-KE Basin water. Evaluation consisted of determining cesium and strontium batch distribution coefficients, loading, and decontamination factors. Actual 105-KE Basin water was obtained from a sample collected during the sludge dissolution work conducted by PNNL in FY 1996. This sample was taken from the bottom of the basin and contained significantly higher concentrations of the radioactive constituents than do samples taken from the top of the basin.

The Social Act of Exchange in Power Relations: The study of the ...

African Journals Online (AJOL)

Key words: Corruption, Nichekeleko, Power relations, Social act of Exchange, Practice. ..... also sampled 18 policemen and Anti-corruption commission officers who ... based upon their availability and knowledge of the activities of Nichekeleko.

Variation in the human lymphocyte sister chromatid exchange frequency as a function of time: results of daily and twice-weekly sampling

Energy Technology Data Exchange (ETDEWEB)

Tucker, J.D.; Christensen, M.L.; Strout, C.L.; McGee, K.A.; Carrano, A.V.

1987-01-01

The variation in lymphocyte sister chromatid exchange (SCE) frequency was investigated in healthy nonsmokers who were not taking any medication. Two separate studies were undertaken. In the first, blood was drawn from four women twice a week for 8 weeks. These donors recorded the onset and termination of menstruation and times of illness. In the second study, blood was obtained from two women and two men for 5 consecutive days on two separate occasions initiated 14 days apart. Analysis of the mean SCE frequencies in each study indicated that significant temporal variation occurred in each donor, and that more variation occurred in the longer study. Some of the variation was found to be associated with the menstrual cycle. In the daily study, most of the variation appeared to be random, but occasional day-to-day changes occurred that were greater than those expected by chance. To determine how well a single SCE sample estimated the pooled mean for each donor in each study, the authors calculated the number of samples that encompassed that donor's pooled mean within 1 or more standard errors. For both studies, about 75% of the samples encompassed the pooled mean within 2 standard errors. An analysis of high-frequency cells (HFCs) was also undertaken. The results for each study indicate that the proportion of HFCs, compared with the use of Fisher's Exact test, is significantly more constant than the means, which were compared by using the t-test. These results coupled with our previous work suggest that HFC analysis may be the method of choice when analyzing data from human population studies.

Ion exchange kinetics of alkaline earths on Zr(IV) arsenosilicate cation exchanger

International Nuclear Information System (INIS)

Varshney, K.G.; Agrawal, S.; Varshney, K.

1984-01-01

A new approach based on the Nernst-Planck equations was applied to study the ion exchange kinetics for the exchange reactions of Mg(II), Ca(II), Sr(II) and Ba(II) with H + -ions at various temperatures on the zirconium(IV) arsenosilicate phase. Under the conditions of particle diffusion, the rate of exchange was found to be independent of the metal ion concentration at and above 0.1 M in aqueous medium. Energy and entropy of activation were determined and found to vary linearly with the ionic radii and mobilities of alkaline earths, a unique feature observed for an inorganic ion exchanger. The results are useful for predicting the ion exchange processes occurring on the surface of an inorganic material of the type studied. (author)

Does exchange rate always affect the number of inbound tourists significantly in China?

OpenAIRE

Xue GAO; Hsu-Ling CHANG; Chi-Wei SU

2018-01-01

This investigation examines the time-varying causality between the exchange rate and the number of the inbound tourism of China using the rolling window estimation. The full-sample causality test suggests no causality between the exchange rate and the number of inbound tourists. However, the parameter stability test revels that this causality is unstable, which suggests that fullsample causality tests cannot be relied upon. Then, we use a time-varying rolling window approach to...

Efficient parallel implementations of QM/MM-REMD (quantum mechanical/molecular mechanics-replica-exchange MD) and umbrella sampling: isomerization of H2O2 in aqueous solution.

Science.gov (United States)

Fedorov, Dmitri G; Sugita, Yuji; Choi, Cheol Ho

2013-07-03

An efficient parallel implementation of QM/MM-based replica-exchange molecular dynamics (REMD) as well as umbrella samplings techniques was proposed by adopting the generalized distributed data interface (GDDI). Parallelization speed-up of 40.5 on 48 cores was achieved, making our QM/MM-MD engine a robust tool for studying complex chemical dynamics in solution. They were comparatively used to study the torsional isomerization of hydrogen peroxide in aqueous solution. All results by QM/MM-REMD and QM/MM umbrella sampling techniques yielded nearly identical potentials of mean force (PMFs) regardless of the particular QM theories for solute, showing that the overall dynamics are mainly determined by solvation. Although the entropic penalty of solvent rearrangements exists in cisoid conformers, it was found that both strong intermolecular hydrogen bonding and dipole-dipole interactions preferentially stabilize them in solution, reducing the torsional free-energy barrier at 0° by about 3 kcal/mol as compared to that in gas phase.

Differential multiple quantum relaxation caused by chemical exchange outside the fast exchange limit

International Nuclear Information System (INIS)

Wang Chunyu; Palmer, Arthur G.

2002-01-01

Differential relaxation of multiple quantum coherences is a signature for chemical exchange processes in proteins. Previous analyses of experimental data have used theoretical descriptions applicable only in the limit of fast exchange. Theoretical expressions for differential relaxation rate constants that are accurate outside fast exchange are presented for two-spin-system subject to two-site chemical exchange. The theoretical expressions are validated using experimental results for 15 N- 1 H relaxation in basic pancreatic trypsin inhibitor. The new theoretical expression is valuable for identification and characterization of exchange processes in proteins using differential relaxation of multiple quantum coherences

Polarized neutron reflectivity study of a thermally treated MnIr/CoFe exchange bias system.

Science.gov (United States)

Awaji, Naoki; Miyajima, Toyoo; Doi, Shuuichi; Nomura, Kenji

2010-12-01

It has recently been found that the exchange bias of a MnIr/CoFe system can be increased significantly by adding a thermal treatment to the bilayer. To reveal the origin of the higher exchange bias, we performed polarized neutron reflectivity measurements at the JRR-3 neutron source. The magnetization vector near the MnIr/CoFe interface for thermally treated samples differed from that for samples without the treatment. We propose a model in which the pinned spin area at the interface is extended due to the increased roughness and atomic interdiffusion that result from the thermal treatment.

Outlook for ion exchange

International Nuclear Information System (INIS)

Kunin, R.

1977-01-01

This paper presents the history and theory of ion exchange technology and discusses the usefulness of ion exchange resins which found broad applications in chemical operations. It is demonstrated that the theory of ion exchange technology seems to be moving away from the physical chemist back to the polymer chemist where it started originally. This but confronted the polymer chemists with some knotty problems. It is pointed out that one has still to learn how to use ion exchange materials as efficiently as possible in terms of the waste load that is being pumped into the environment. It is interesting to note that, whereas ion exchange is used for abating pollution, it is also a polluter. One must learn how to use ion exchange as an antipollution device, and at the same time minimize its polluting properties

Longitudinal exchange: an alternative strategy towards quantification of dynamics parameters in ZZ exchange spectroscopy

International Nuclear Information System (INIS)

Kloiber, Karin; Spitzer, Romana; Grutsch, Sarina; Kreutz, Christoph; Tollinger, Martin

2011-01-01

Longitudinal exchange experiments facilitate the quantification of the rates of interconversion between the exchanging species, along with their longitudinal relaxation rates, by analyzing the time-dependence of direct correlation and exchange cross peaks. Here we present a simple and robust alternative to this strategy, which is based on the combination of two complementary experiments, one with and one without resolving exchange cross peaks. We show that by combining the two data sets systematic errors that are caused by differential line-broadening of the exchanging species are avoided and reliable quantification of kinetic and relaxation parameters in the presence of additional conformational exchange on the ms–μs time scale is possible. The strategy is applied to a bistable DNA oligomer that displays different line-broadening in the two exchanging species.

Analytical applications of ion exchangers

CERN Document Server

Inczédy, J

1966-01-01

Analytical Applications of Ion Exchangers presents the laboratory use of ion-exchange resins. This book discusses the development in the analytical application of ion exchangers. Organized into 10 chapters, this book begins with an overview of the history and significance of ion exchangers for technical purposes. This text then describes the properties of ion exchangers, which are large molecular water-insoluble polyelectrolytes having a cross-linked structure that contains ionic groups. Other chapters consider the theories concerning the operation of ion-exchange resins and investigate th

Methane emissions abatement by multi-ion-exchanged zeolite A prepared from both commercial-grade zeolite and coal fly ash.

Science.gov (United States)

Hui, K S; Chao, C Y H

2008-10-01

The performance of multimetal-(Cu, Cr, Zn, Ni, and Co)-ion-exchanged zeolite A prepared from both a commercial-grade sample and one produced from coal fly ash in methane emissions abatement was evaluated in this study. The ion-exchange process was used to load the metal ions in zeolite A samples. The methane conversion efficiency by the samples was studied under various parameters including the amount of metal loading (7.3-19.4 wt%), reaction temperature (25-500 degrees C), space velocity (8400-41 900 h(-1)), and methane concentration (0.5-3.2 vol %). At 500 degrees C, the original commercial-grade zeolite A catalyzed 3% of the methane only, whereas the addition of different percentages of metals in the sample enhanced the methane conversion efficiency by 40-85%. Greater methane conversion was observed by increasing the percentage of metals added to the zeolite even though the BET surface area of the zeolite consequently decreased. Higher percentage methane conversion over the multi-ion-exchanged samples was observed at lower space velocities indicating the importance of the mass diffusion of reactants and products in the zeolite. Compared to the multi-ion-exchanged zeolite A prepared from the commercial-grade zeolite, the one produced from coal fly ash demonstrated similar performances in methane emissions abatement, showing the potential use of this low cost recycled material in gaseous pollutant treatment.

Agreement between pre-operative and intra-operative bacteriological samples in 85 chronic peri-prosthetic infections.

Science.gov (United States)

Matter-Parrat, V; Ronde-Oustau, C; Boéri, C; Gaudias, J; Jenny, J-Y

2017-04-01

Whether pre-operative microbiological sampling contributes to the management of chronic peri-prosthetic infection remains controversial. We assessed agreement between the results of pre-operative and intra-operative samples in patients undergoing single-stage prosthesis exchange to treat chronic peri-prosthetic infection. Agreement between pre-operative and intra-operative samples exceeds 75% in patients undergoing single-stage exchange of a hip or knee prosthesis to treat chronic peri-prosthetic infection. This single-centre retrospective study included 85 single-stage prosthesis exchange procedures in 82 patients with chronic peri-prosthetic infection at the hip or knee. Agreement between pre-operative and intra-operative sample results was evaluated. Changes to the initial antibiotic regimen made based on the intra-operative sample results were recorded. Of 149 pre-operative samples, 109 yielded positive cultures, in 75/85 cases. Of 452 intra-operative samples, 354 yielded positive cultures, in 85/85 cases. Agreement was complete in 54 (63%) cases and partial in 9 (11%) cases; there was no agreement in the remaining 22 (26%) cases. The complete agreement rate was significantly lower than 75% (P=0.01). The initial antibiotic regimen was inadequate in a single case. Pre-operative sampling may contribute to the diagnosis of peri-prosthetic infection but is neither necessary nor sufficient to confirm the diagnosis and identify the causative agent. The spectrum of the initial antibiotic regimen cannot be safely narrowed based on the pre-operative sample results. We suggest the routine prescription of a probabilistic broad-spectrum antibiotic regimen immediately after the prosthesis exchange, even when a pathogen was identified before surgery. IV, retrospective study. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Evaluation of capacity ion exchange of MMT-Na+with rare earth salts for use in polymeric nano composites

International Nuclear Information System (INIS)

Maino, Isabel B.; Scienza, Lisete C.; Piazza, Diego; Zattera, Ademir J.; Ferreira, Carlos A.

2011-01-01

The modification of the montmorillonite clay is associated with materials science, arousing interest in science and technology provide significant improvements when incorporated into polymeric materials neat and conventional composites. The process of modification of clays occurs mainly through the ion exchange of exchangeable cations in its crystal structure. In this study, we performed ion exchange of sodium montmorillonite with rare earth salts (cerium) through two routes: centrifugation and filtration. The samples were characterized by X-ray diffraction (XRD) and energy dispersive analysis by X-ray (EDS). The sample obtained by the filtration route showed an increase of basal clay by XRD, indicating the presence of salts of cerium on the structure, and corroborated by EDS analysis. (author)

Evidence of exchange-coupled behavior in chromium-cobalt ferrite nanoparticles

Science.gov (United States)

Tanbir, Kamar; Sharma, Lalit Kumar; Aakash; Singh, Rakesh Kumar; Choubey, Ravi Kant; Mukherjee, Samrat

2018-06-01

Cr doped cobalt ferrite nanoparticles were synthesized with the generic formula Co1-xCrxFe2O4 (x = 0, 0.05, 0.15, 0.25) through standard chemical co-precipitation method. XRD studies confirmed the pure spinel cubic structure belonging to Fd 3 bar m space group. From the Williamson-Hall plots, crystallite sizes were found to lie within the range (42 ± 1) nm for the different doped samples. The lattice parameter was found to decrease linearly with increase in the concentration of Cr3+ ion. The magnetic behavior of the samples was determined by M-H studies at 300 K, field cooled (5 T) at 5 K and temperature dependent studies. The M-H at 300 K show soft magnetic behavior whereas the M-H plots at 5 K predict the existence of in-homogeneity of the exchange interactions due to strong exchange coupling between the spins at the core and the surface of the nanoparticles.

Data quality objectives for Ion Exchange Module (IXM) disposition

International Nuclear Information System (INIS)

Choi, I.

1995-01-01

This Data Quality Objective (DQO) document presents the data needs and accuracy requirements for sampling ion exchange modules at the K Basins, 100 K Area, to determine if there is a hydrogen gas buildup within the modules. This document was produced by PNL, with the assistance of Neptune and Associates, and was partly funded (for facilitator) by DOE-HQ as a demonstration DQO for EM activities. PNL involved a number of PNL, WHC and support contract staff (including external technical consultants) in meetings to define the data needed, along with the necessary accuracy, to resolve issues associated with hydrogen accumulation in Ion Exchange Modules (IXMS) that were generated prior to July 1994 and only have one nuc-fil vent. IXMs generated after July 1994 have multiple nuc-fil vents and do not require sampling. PNL transmitted this DQO to WHC on January 31, 1995. This Supporting Document is to assure that the document is captured into the document retrieval system. WHC review focused on the acceptability of the technical conclusions such that the data collected will meet minimum operational, safety and environmental needs

High-throughput preparation and testing of ion-exchanged zeolites

International Nuclear Information System (INIS)

Janssen, K.P.F.; Paul, J.S.; Sels, B.F.; Jacobs, P.A.

2007-01-01

A high-throughput research platform was developed for the preparation and subsequent catalytic liquid-phase screening of ion-exchanged zeolites, for instance with regard to their use as heterogeneous catalysts. In this system aqueous solutions and other liquid as well as solid reagents are employed as starting materials and 24 samples are prepared on a library plate with a 4 x 6 layout. Volumetric dispensing of metal precursor solutions, weighing of zeolite and subsequent mixing/washing cycles of the starting materials and distributing reaction mixtures to the library plate are automatically performed by liquid and solid handlers controlled by a single common and easy-to-use programming software interface. The thus prepared materials are automatically contacted with reagent solutions, heated, stirred and sampled continuously using a modified liquid handling. The high-throughput platform is highly promising in enhancing synthesis of catalysts and their screening. In this paper the preparation of lanthanum-exchanged NaY zeolites (LaNaY) on the platform is reported, along with their use as catalyst for the conversion of renewables

Social dilemmas as exchange dilemmas

NARCIS (Netherlands)

Dijkstra, Jacob; van Assen, Marcel A.L.M.

2016-01-01

We develop a new paradigm to study social dilemmas, called exchange dilemmas. Exchange dilemmas arise from externalities of exchanges with third parties, and many real-life social dilemmas are more accurately modeled as exchange dilemmas rather than prisoner's dilemmas. Building on focusing and

Social dilemmas as exchange dilemmas

NARCIS (Netherlands)

Dijkstra, J.; van Assen, M.A.L.M.

2016-01-01

We develop a new paradigm to study social dilemmas, called exchange dilemmas. Exchange dilemmas arise from externalities of exchanges with third parties, and many real-life social dilemmas are more accurately modeled as exchange dilemmas rather than prisoner's dilemmas. Bulding on focusing and

The structure of social exchange in self-help support groups: development of a measure.

Science.gov (United States)

Brown, Louis D; Tang, Xiaohui; Hollman, Ruth L

2014-03-01

Self-help support groups are indigenous community resources designed to help people manage a variety of personal challenges, from alcohol abuse to xeroderma pigmentosum. The social exchanges that occur during group meetings are central to understanding how people benefit from participation. This paper examines the different types of social exchange behaviors that occur during meetings, using two studies to develop empirically distinct scales that reliably measure theoretically important types of exchange. Resource theory informed the initial measurement development efforts. Exploratory factor analyses from the first study led to revisions in the factor structure of the social exchange scales. The revised measure captured the exchange of emotional support, experiential information, humor, unwanted behaviors, and exchanges outside meetings. Confirmatory factor analyses from a follow-up study with a different sample of self-help support groups provided good model fit, suggesting the revised structure accurately represented the data. Further, the scales demonstrated good convergent and discriminant validity with related constructs. Future research can use the scales to identify aspects of social exchange that are most important in improving health outcomes among self-help support group participants. Groups can use the scales in practice to celebrate strengths and address weaknesses in their social exchange dynamics.

Leader - Member Exchange in Different Organizational Cultures and Effects to Organizational Burnout

Directory of Open Access Journals (Sweden)

Erdem Kırkbeşoğlu

2014-06-01

Full Text Available The purpose of this study is to examine the effect of leader- member exchange to burnout syndrome in different organizational cultures. Sample of the study is constituted by 183 participants who work in life insurance companies which represent organic organizational culture and non-life insurance companies which represent mechanical organizational culture. As a result of regression and correlation analysis, it is determined that leader-member exchange in organic organizational culture affects organizational culture negatively and in higher level compared to mechanical organizational cultures.

Foundations and latest advances in replica exchange transition interface sampling

NARCIS (Netherlands)

Cabriolu, R.; Refsnes, K.M.S; Bolhuis, P.G.; van Erp, T.S.

2017-01-01

Nearly 20 years ago, transition path sampling (TPS) emerged as an alternative method to free energy based approaches for the study of rare events such as nucleation, protein folding, chemical reactions, and phase transitions. TPS effectively performs Monte Carlo simulations with relatively short

Colour-singlet exchange and tests of models of diffractive DIS

International Nuclear Information System (INIS)

Williams, J.C.

2000-03-01

Diffractive deep-inelastic scattering events observed at the HERA electron-proton collider are interpreted as an interaction involving a virtual photon scattering off a colour-singlet state within the proton. Models which attempt to describe the colour-singlet exchanged in diffractive interactions range from the purely phenomenological Donnachie-Landshoff form factor approach to the QCD-motivated gluon-exchange models and the scalar-pomeron model. It is important to find ways to test these models. In this thesis colour-singlet exchange models of diffractive DIS are compared with cross section and structure function data from the H1 detector. H1 select diffractive data by requiring there to be a large angle between the forward proton direction and any other significant detector activity. This pseudo-rapidity gap cut extracts colour-singlet exchange events from the standard DIS data sample. For a wide range of the parameter space covered by the HERA experiments, however, the pseudo-rapidity gap cuts restrict the final-state phase space available for diffractive scattering. One consequence is that pseudo-rapidity gap cuts can be used to select diffractive events in which the colour-singlet only couples to off-shell partons. To leading order in the strong coupling constant, the diffractive final state consists of a quark-antiquark pair. Higher-order events include diffractive production of quark-antiquark-gluon states. In the region where pseudo-rapidity gap cuts restrict the accessible phase space, the cuts reject low transverse momentum quark-antiquark diffractive events. Pseudo-rapidity gap data selection cuts also allow selection of an enhanced 3-jet data sample. The structure function and transverse momentum distribution data can be described by either a two-gluon model or by the Donnachie-Landshoff model, both models requiring a significant contribution from quark-antiquark-gluon diffractive final states to fit the full kinematic range of the diffractive data

Update heat exchanger designing principles

International Nuclear Information System (INIS)

Lipets, A.U.; Yampol'skij, A.E.

1985-01-01

Update heat exchanger design principles are analysed. Different coolant pattern in a heat exchanger are considered. It is suggested to rationally organize flow rates irregularity in it. Applying on heat exchanger designing measures on using really existing temperature and flow rate irregularities will permit to improve heat exchanger efficiency. It is expedient in some cases to artificially produce irregularities. In this connection some heat exchanger design principles must be reviewed now

Identification of genetically modified DNA found in Roundup Ready soybean using gold nanoparticles

International Nuclear Information System (INIS)

Jang, Huisoo; Kwak, Cheol Hwan; Kim, Gibum; Kim, Sun Min; Huh, Yun Suk; Jeon, Tae-Joon

2016-01-01

The authors describe an SPR sensor chip coated with gold nanoparticles (AuNPs) that enables highly sensitive determination of genetically modified (GM) crops. Detection is based on localized surface plasmon resonance (LSPR) with its known sensitivity to even minute changes in refractive index. The device consists of a halogen light source, a light detector, and a cuvette cell that contains a sensor chip coated with AuNPs. It is operated in the transmission mode of the optical path to enhance the plasmonic signal. The sample solution containing target DNA (e.g. from the GM crop) is introduced into the cuvette with the sensor chip whose surface was functionalized with a capture DNA. Following a 30-min hybridization, the changes of the signal are recorded at 540 nm. The chip responds to target DNA in the 1 to 100 nM concentration range and has a 1 nM detection limit. Features of this sensor chip include a short reaction time, ease of handling, and portability, and this enables on-site detection and in-situ testing. (author)

Persorption of 35S-labelled cation exchangers in mammals

International Nuclear Information System (INIS)

Dedek, W.; Grahl, R.; Mothes, B.; Reuter, H.; Sabrowski, E.; Moehring, M.

1983-01-01

Persorption rates were determined of 35 S-labelled cation exchangers (sulphonated polystyrene-divinyl benzene copolymerisate) in two particle sizes, between 80μm and 125μm and smaller than 45μm in diameter, following oral administration to pigs of one single dose of 5 g / 25 kg body weight. Maximum persorption rates were 5 x 10 -3 after 51 hours and 7 x 10 -4 after 35 days for the larger particle size. For the fine grain sample the persorption rate showed already after 51 hours a lower value of 2 x 10 -3 , after 35 days it reached with 5 x 10 -4 approximately the same value as it was observed with the large grain sample. About 80 per cent of all substance recorded had been absorbed by muscles. Only less than 1 x 10 -4 of water-soluble 35 S activity and less than 2 x 10 -5 of solid particles were recordable from urine and could be, as well, identified directly by means of autoradiography. The number of particles absorbed by fine grain samples was roughly a hundred times higher than that in large grain samples. However, absorbed amounts were approximately the same after 35 days, related to the SO 3 H group active in ion exchange. The conclusion was drawn that no dependence of persorption rates on particle size was any longer detectable, when 35 days had passed. (author)

Compact heat exchanger for power plants

International Nuclear Information System (INIS)

Kinnunen, L.

2001-01-01

Vahterus Oy, located at Kalanti, has manufactured heat exchangers since the beginning of 1990s. About 90% of the equipment produced are exported. In the PSHE (Plate and Shell) solution of the Vahterus heat exchanger the heat is transferred by round plated welded to form a compact package, which is assembled into a cylindrical steel casing. The heat exchanger contains no gaskets or soldered joints, which eliminates the leak risks. Traditional heat exchanges are usually operated at higher temperatures and pressures, but the heat transfer capacities of them are lower. Plate heat exchangers, on the other hand, are efficient, but the application range of them is narrow. Additionally, the rubber gasket of the heat exchange plates, sealing the joints of the heat exchanging plates, does not stand high pressures or temperatures, or corroding fluids. The new welded plate heat exchanger combine the pressure and temperature resistance of tube heat exchangers and the high heat exchange capacity of plate heat exchangers. The new corrosion resisting heat exchanger can be applied for especially hard conditions. The operating temperature range of the PSHE heat exchanger is - 200 - 900 deg C. The pressure resistance is as high as 100 bar. The space requirement of PSHE is only one tenth of the space requirement of traditional tube heat exchangers. Adjusting the number of heat exchanging plates can change the capacity of the heat exchanger. Power range of the heat exchanger can be as high as 80 MW. Due to the corrosion preventive construction and the small dimension the PSHE heat exchanger can be applied for refrigerators using ammonia as refrigerant. These kinds of new Vahterus heat exchangers are in use in 60 countries in more than 2000 refrigerators

Exchanging Description Logic Knowledge Bases

NARCIS (Netherlands)

Arenas, M.; Botoeva, E.; Calvanese, D.; Ryzhikov, V.; Sherkhonov, E.

2012-01-01

In this paper, we study the problem of exchanging knowledge between a source and a target knowledge base (KB), connected through mappings. Differently from the traditional database exchange setting, which considers only the exchange of data, we are interested in exchanging implicit knowledge. As

Automated Sample Preparation for Radiogenic and Non-Traditional Metal Isotopes: Removing an Analytical Barrier for High Sample Throughput

Science.gov (United States)

Field, M. Paul; Romaniello, Stephen; Gordon, Gwyneth W.; Anbar, Ariel D.; Herrmann, Achim; Martinez-Boti, Miguel A.; Anagnostou, Eleni; Foster, Gavin L.

2014-05-01

MC-ICP-MS has dramatically improved the analytical throughput for high-precision radiogenic and non-traditional isotope ratio measurements, compared to TIMS. The generation of large data sets, however, remains hampered by tedious manual drip chromatography required for sample purification. A new, automated chromatography system reduces the laboratory bottle neck and expands the utility of high-precision isotope analyses in applications where large data sets are required: geochemistry, forensic anthropology, nuclear forensics, medical research and food authentication. We have developed protocols to automate ion exchange purification for several isotopic systems (B, Ca, Fe, Cu, Zn, Sr, Cd, Pb and U) using the new prepFAST-MC™ (ESI, Nebraska, Omaha). The system is not only inert (all-flouropolymer flow paths), but is also very flexible and can easily facilitate different resins, samples, and reagent types. When programmed, precise and accurate user defined volumes and flow rates are implemented to automatically load samples, wash the column, condition the column and elute fractions. Unattended, the automated, low-pressure ion exchange chromatography system can process up to 60 samples overnight. Excellent reproducibility, reliability, recovery, with low blank and carry over for samples in a variety of different matrices, have been demonstrated to give accurate and precise isotopic ratios within analytical error for several isotopic systems (B, Ca, Fe, Cu, Zn, Sr, Cd, Pb and U). This illustrates the potential of the new prepFAST-MC™ (ESI, Nebraska, Omaha) as a powerful tool in radiogenic and non-traditional isotope research.

Atmospheric pressure photo ionization hydrogen/deuterium exchange mass spectrometry--a method to differentiate isomers by mass spectrometry.

Science.gov (United States)

Ahmed, Arif; Kim, Sunghwan

2013-12-01

In this report, a method for in-source hydrogen/deuterium (H/D) exchange at atmospheric pressure is reported. The method was named atmospheric pressure photo ionization hydrogen/deuterium exchange mass spectrometry (APPI HDX MS). H/D exchange was performed by mixing samples dissolved in toluene with CH3OD solvent and analyzing the mixture using atmospheric pressure photo ionization mass spectrometry (APPI-MS). The APPI HDX spectra obtained with contact times between the analyte solution and methanol-OD (CH3OD) of atmospheric pressure. H/D exchange can be performed in any laboratory with a mass spectrometer and a commercial APPI source. Using this method, multiple H/D exchanges of aromatic hydrogen and/or H/D exchange of active hydrogen were observed. These results demonstrated that H/D exchange can be used to distinguish between isomers containing primary, secondary, and tertiary amines, as well as pyridine and pyrrole functional groups.

Social dilemmas as exchange dilemmas

OpenAIRE

Dijkstra, J.; van Assen, M.A.L.M.

2016-01-01

We develop a new paradigm to study social dilemmas, called exchange dilemmas. Exchange dilemmas arise from externalities of exchanges with third parties, and many real-life social dilemmas are more accurately modeled as exchange dilemmas rather than prisoner's dilemmas. Bulding on focusing and framing research we predict that defection is omnipresent in exchange dilemmas, which is corroborated in to very different experiments. Our results suggest that the fundamental problem of cooperation in...

Daily Social Exchanges and Affect in Middle and Later Adulthood: The Impact of Loneliness and Age

Science.gov (United States)

Russell, Alissa; Bergeman, C. S.; Scott, Stacey B.

2012-01-01

Although daily social exchanges are important for well-being, it is unclear how different types of exchanges affect daily well-being, as well as which factors influence the way in which individuals react to their daily social encounters. The present study included a sample of 705 adults aged 31 to 91, and using Multilevel Modeling analyses…

Apparatus and process for deuterium exchange

International Nuclear Information System (INIS)

Ergenc, M.S.

1976-01-01

The deuterium exchange plant is combined with an absorption refrigeration plant in order to improve the exchange process and to produce refrigeration. The refrigeration plant has a throttling means for expanding and cooling a portion of the liquid exchange medium separated in the exchange plant as well as an evaporator, in which the said liquid exchange medium is brought into heat exchange with a cold consumer device, absorption means for forming a solution of the used exchange medium and fresh water and a pump for pumping the solution into the exchange plant

Exchange, x-ray and IR spectral behaviour of lanthanum and praseodymium exchanged zeolite X

International Nuclear Information System (INIS)

Das, D.; Upreti, M.C.

1995-01-01

Exchange behaviour of lanthanum and praseodymium ions in zeolite X involves three steps: preferential exchange, intrazeolitic exchange and irreversible exchange. At room temperature , higher exchange has been observed with La(III) than with Pr(III) which is attributed to the smaller hydrosphere of lanthanum than praseodymium. IR spectra of these zeolites in KBr pellets show a shift in the major Si-O stretching vibration of 972 cm -1 to higher frequencies. Their x-ray diffraction patterns remain unchanged except a large decrease of the line intensities caused by the absorption of x-rays by heavy La(III) and Pr(III) ions. The present study reports the preparation and physicochemical properties of lanthanum and praseodymium exchanged zeolite X. (author). 12 refs., 3 figs., 3 tabs

Isotopically exchangeable phosphorus

International Nuclear Information System (INIS)

Barbaro, N.O.

1984-01-01

A critique revision of isotope dilution is presented. The concepts and use of exchangeable phosphorus, the phosphate adsorption, the kinetics of isotopic exchange and the equilibrium time in soils are discussed. (M.A.C.) [pt

Exchange anisotropy and micromagnetic properties of PtMn/NiFe bilayers

International Nuclear Information System (INIS)

Pokhil, Taras; Linville, Eric; Mao, Sining

2001-01-01

Magnetic microstructure, exchange induced uniaxial and unidirectional anisotropy and structural transformation have been studied in PtMn/NiFe bilayer films and small elements as a function of annealing time. The relationship between the fcc-fct ordering phase transformation in PtMn and the development of exchange induced magnetic properties in PtMn/NiFe bilayers is complicated by the fact that the transformation occurs throughout the entire volume of the PtMn film, while the exchange between the layers is predominantly an interface effect. Consequently, the development of the exchange anisotropy should depend primarily on the character of the structural transformation at the interface between PtMn and NiFe. The purpose of this article is to correlate the volume phase transformation in PtMn to the development of exchange anisotropy and micromagnetic behavior in PtMn/NiFe bilayers. The interface structure can be inferred from the anisotropy and micromagnetic measurements, leading to a model that explains the relationship between the volume and interface transformation structures in PtMn, and magnetic properties of the bilayers. The structure and magnetic properties were characterized by x-ray diffraction, vibrating sample magnetometry, and magnetic force microscopy. [copyright] 2001 American Institute of Physics

Is a more stable exchange rate associated with reduced exchange rate pass-through?

OpenAIRE

Mark J. Holmes

2007-01-01

Pass-through from the nominal effective exchange rate to import prices is modelled within a regime-switching environment. Evidence suggests that exchange rate pass through can be characterised as regime-specific where the probability of switching between regimes is influenced by the extent of exchange rate volatility.

Exchange of Information in Tax Matters

Directory of Open Access Journals (Sweden)

Paweł Szwajdler

2017-01-01

Full Text Available The main aim of this paper is to present issues related to exchange of tax information. The author focuses on models of exchange of information and boundaries of obligations in reference to above-mentioned problems. Automatic exchange of information, spontaneous exchange of information and exchange of information on request are analysed in this work on the base of OECD Convention on Mutual Administrative Assistance in Tax Matters, Council Directive 2011/16 and OECD Model Agreement on Exchange of Information in Tax Matters. In the summary, it was showed that the most efficient method of exchange of tax information is automatic exchange of information. Furthermore, it was stated that exchange on request can be related to negative phenomenon such as fishing expedition. Spontaneous exchange of information is thought to play only supportive role.  The author also considers that boundaries of exchange of information in tax matters were regulated so as to protect jeopardised raison d’ État.

Exchangeable phosphorus and others parameters in soil samples from Sapucai

International Nuclear Information System (INIS)

Facetti, J.F.; Zanotti, J.F.

1972-01-01

Soils samples from the alkaline rocks area at Sapucai were studied. The total amount of P in the soils shows to be high, as well as the E value for the 32 P exclangeable phosphorus. Other parameters like V values, TEC, etc., and their relationschip also were analyzed

Exchangeable phosphorus and others parameters in soil samples from Sapucai

Energy Technology Data Exchange (ETDEWEB)

Facetti, J F; Zanotti, J F [Asuncion Nacional Univ. (Paraguay). Inst. de Ciencias

1972-01-01

Soils samples from the alkaline rocks area at Sapucai were studied. The total amount of P in the soils shows to be high, as well as the E value for the 32 P exclangeable phosphorus. Other parameters like V values, TEC, etc., and their relationschip also were analyzed.

Bretton Woods Fixed Exchange Rate System versus Floating Exchange Rate System

OpenAIRE

Geza, Paula; Giurca Vasilescu, Laura

2011-01-01

One of the most important issues of monetary policy is to find out whether the state should intervene among the exchange rates, taking into account the fact that changes in the exchange rates represent a significant transmission channel of the effects generated by the monetary policy. Taking into consideration the failure of fixed exchange rate regimes and the recent improvement of financial markets, the return in the near future to such a regime – as for example the Bretton Woods system –...

A column exchange chromatographic procedure for the automated purification of analytical samples in nuclear spent fuel reprocessing and plutonium fuel fabrication

International Nuclear Information System (INIS)

Zahradnik, P.; Swietly, H.; Doubek, N.; Bagliano, G.

1992-11-01

A Column Exchange Chromatographic procedure using Tri-n-Octyl-Phosphine-Oxide (TOPO) as stationary phase, is in routine use at SAL since 1984 on nuclear spent fuel reprocessing and on Pu product samples, prior to alpha and mass spectrometric analysis. This standard procedure was further on modified in view of its automation in a glove box; the resulting new procedure is described in this paper. Laboratory Robot Compatible (LRC) disposable columns were selected because their dimensions are particularly favorable and reproducible. A less corrosive HNO 3 -HI mixture substituted the former HC1-HI plutonium eluant. The inorganic support of the stationary phase used to test the above mentioned changes was unexpectedly withdrawn from the market so that another support had to be selected and the procedure reoptimized accordingly. The resulting procedure was tested with the robot and validated against the manual procedure taken as reference: the comparison showed that the modified procedure meets the analytical requirements and has the same performance than the original procedure. (author). Refs, figs and tabs

Hydrogen exchange

DEFF Research Database (Denmark)

Jensen, Pernille Foged; Rand, Kasper Dyrberg

2016-01-01

Hydrogen exchange (HX) monitored by mass spectrometry (MS) is a powerful analytical method for investigation of protein conformation and dynamics. HX-MS monitors isotopic exchange of hydrogen in protein backbone amides and thus serves as a sensitive method for probing protein conformation...... and dynamics along the entire protein backbone. This chapter describes the exchange of backbone amide hydrogen which is highly quenchable as it is strongly dependent on the pH and temperature. The HX rates of backbone amide hydrogen are sensitive and very useful probes of protein conformation......, as they are distributed along the polypeptide backbone and form the fundamental hydrogen-bonding networks of basic secondary structure. The effect of pressure on HX in unstructured polypeptides (poly-dl-lysine and oxidatively unfolded ribonuclease A) and native folded proteins (lysozyme and ribonuclease A) was evaluated...

Anion exchange membrane

Science.gov (United States)

Verkade, John G; Wadhwa, Kuldeep; Kong, Xueqian; Schmidt-Rohr, Klaus

2013-05-07

An anion exchange membrane and fuel cell incorporating the anion exchange membrane are detailed in which proazaphosphatrane and azaphosphatrane cations are covalently bonded to a sulfonated fluoropolymer support along with anionic counterions. A positive charge is dispersed in the aforementioned cations which are buried in the support to reduce the cation-anion interactions and increase the mobility of hydroxide ions, for example, across the membrane. The anion exchange membrane has the ability to operate at high temperatures and in highly alkaline environments with high conductivity and low resistance.

Radial flow heat exchanger

Science.gov (United States)

Valenzuela, Javier

2001-01-01

A radial flow heat exchanger (20) having a plurality of first passages (24) for transporting a first fluid (25) and a plurality of second passages (26) for transporting a second fluid (27). The first and second passages are arranged in stacked, alternating relationship, are separated from one another by relatively thin plates (30) and (32), and surround a central axis (22). The thickness of the first and second passages are selected so that the first and second fluids, respectively, are transported with laminar flow through the passages. To enhance thermal energy transfer between first and second passages, the latter are arranged so each first passage is in thermal communication with an associated second passage along substantially its entire length, and vice versa with respect to the second passages. The heat exchangers may be stacked to achieve a modular heat exchange assembly (300). Certain heat exchangers in the assembly may be designed slightly differently than other heat exchangers to address changes in fluid properties during transport through the heat exchanger, so as to enhance overall thermal effectiveness of the assembly.

Quantification of protein backbone hydrogen-deuterium exchange rates by solid state NMR spectroscopy

International Nuclear Information System (INIS)

Lopez del Amo, Juan-Miguel; Fink, Uwe; Reif, Bernd

2010-01-01

We present the quantification of backbone amide hydrogen-deuterium exchange rates (HDX) for immobilized proteins. The experiments make use of the deuterium isotope effect on the amide nitrogen chemical shift, as well as on proton dilution by deuteration. We find that backbone amides in the microcrystalline α-spectrin SH3 domain exchange rather slowly with the solvent (with exchange rates negligible within the individual 15 N-T 1 timescales). We observed chemical exchange for 6 residues with HDX exchange rates in the range from 0.2 to 5 s -1 . Backbone amide 15 N longitudinal relaxation times that we determined previously are not significantly affected for most residues, yielding no systematic artifacts upon quantification of backbone dynamics (Chevelkov et al. 2008b). Significant exchange was observed for the backbone amides of R21, S36 and K60, as well as for the sidechain amides of N38, N35 and for W41ε. These residues could not be fit in our previous motional analysis, demonstrating that amide proton chemical exchange needs to be considered in the analysis of protein dynamics in the solid-state, in case D 2 O is employed as a solvent for sample preparation. Due to the intrinsically long 15 N relaxation times in the solid-state, the approach proposed here can expand the range of accessible HDX rates in the intermediate regime that is not accessible so far with exchange quench and MEXICO type experiments.

Rapid and automated determination of plutonium and neptunium in environmental samples

International Nuclear Information System (INIS)

Qiao, J.

2011-03-01

This thesis presents improved analytical methods for rapid and automated determination of plutonium and neptunium in environmental samples using sequential injection (SI) based chromatography and inductively coupled plasma mass spectrometry (ICP-MS). The progress of methodology development in this work consists of 5 subjects stated as follows: 1) Development and optimization of an SI-anion exchange chromatographic method for rapid determination of plutonium in environmental samples in combination of inductively coupled plasma mass spectrometry detection (Paper II); (2) Methodology development and optimization for rapid determination of plutonium in environmental samples using SI-extraction chromatography prior to inductively coupled plasma mass spectrometry (Paper III); (3) Development of an SI-chromatographic method for simultaneous determination of plutonium and neptunium in environmental samples (Paper IV); (4) Investigation of the suitability and applicability of 242 Pu as a tracer for rapid neptunium determination using anion exchange chromatography in an SI-network coupled with inductively coupled plasma mass spectrometry (Paper V); (5) Exploration of macro-porous anion exchange chromatography for rapid and simultaneous determination of plutonium and neptunium within an SI system (Paper VI). The results demonstrate that the developed methods in this study are reliable and efficient for accurate assays of trace levels of plutonium and neptunium as demanded in different situations including environmental risk monitoring and assessment, emergency preparedness and surveillance of contaminated areas. (Author)

Rapid and automated determination of plutonium and neptunium in environmental samples

Energy Technology Data Exchange (ETDEWEB)

Qiao, J.

2011-03-15

This thesis presents improved analytical methods for rapid and automated determination of plutonium and neptunium in environmental samples using sequential injection (SI) based chromatography and inductively coupled plasma mass spectrometry (ICP-MS). The progress of methodology development in this work consists of 5 subjects stated as follows: 1) Development and optimization of an SI-anion exchange chromatographic method for rapid determination of plutonium in environmental samples in combination of inductively coupled plasma mass spectrometry detection (Paper II); (2) Methodology development and optimization for rapid determination of plutonium in environmental samples using SI-extraction chromatography prior to inductively coupled plasma mass spectrometry (Paper III); (3) Development of an SI-chromatographic method for simultaneous determination of plutonium and neptunium in environmental samples (Paper IV); (4) Investigation of the suitability and applicability of 242Pu as a tracer for rapid neptunium determination using anion exchange chromatography in an SI-network coupled with inductively coupled plasma mass spectrometry (Paper V); (5) Exploration of macro-porous anion exchange chromatography for rapid and simultaneous determination of plutonium and neptunium within an SI system (Paper VI). The results demonstrate that the developed methods in this study are reliable and efficient for accurate assays of trace levels of plutonium and neptunium as demanded in different situations including environmental risk monitoring and assessment, emergency preparedness and surveillance of contaminated areas. (Author)

Ion exchanger material based on Titanium phosphate for liquid radioactive waste treatment

Energy Technology Data Exchange (ETDEWEB)

Maslova, M.; Gerasimova, L. [Tananaev Institute of Chemistry and Technology of Rare Elements and Mineral Resources, Kola Scientific Center, Russian Academy of Sciences, Apatity (Russian Federation)

2013-07-01

A comparative study of the physicochemical and service properties of samples of Ti(OH) 1.36(HPO4) 1.32 * 2.3H2O sorbent in the finely dispersed and granulated forms, mastered for commercial production, was made. The sorption of Cs and Sr cations from solutions of various, compositions was studied in batch experiments, and the diffusion coefficients of the exchanging ions were determined. The hydrolytic stability of the. sorbents was examined with the aim to determine the optimal operation conditions. Experiments showed that the cation exchangers based on titanium phosphate are the most efficient in removal from liquid radioactive waste of induced radioactive isotopes of corrosion products, which is due to formation of weakly dissociating compounds of nonferrous metal ions with functional groups of the ion exchangers in the sorbent phase. (author)

Reduction of exchangeable calcium and magnesium in soil with increasing pH

Directory of Open Access Journals (Sweden)

Miyazawa Mário

2001-01-01

Full Text Available A laboratory study was conducted with soil samples and synthetic solutions to investigate possible mechanisms related with reduction in KCl exchangeable Ca and Mg with increasing pH. Increasing soil pH over 5.3 with CaCO3 added to the soil and with NaOH solution added to soil/KCl suspension increased adsorptions of Ca and Mg. The reduction of Mg was greater than Ca and was related to the concentration of soil exchangeable Al. The decreases of soluble Ca and Mg following addition of Al in synthetic solution were at pH > 7.5. The isomorphic coprecipitation reaction with Al compounds may be the most possible mechanism responsible for the decrease of exchangeable Ca and Mg with increasing pH. Possible chemical reactions are presented.

Isotope exchange of molecular oxygen with oxygen of La0,7Sr0,3CoO3-δ

International Nuclear Information System (INIS)

Vdovin, G.K.; Kuzin, B.L.; Kurumchin, Eh.Kh.

1991-01-01

The exchange rate of the oxygen in La 0,7 Sr 0,3 CoO 3-δ has been measured by an isotopic exchange method at temperatures 620-1250 K and pressures 1.6-10 torr. The activation energy and the dependence of the exchange rate on pressures in gas have been defined. It is suggested that the knees on the temperature dependences of the exchange rate are attributed to the appearance of Co 2+ ions on the surface of the sample at elevated temperature as new centres of the exchange reaction. The activation energies of the adsorption and desorption processes on the La 0,7 Sr 0,3 CoO 3-δ surface have been estimated

Determination of Mercury in Aqueous Samples by Means of Neutron Activation Analysis with an Account of Flux Disturbances

Energy Technology Data Exchange (ETDEWEB)

Brune, D; Jirlow, K

1967-08-15

The technique of low temperature neutron irradiation combined with isotopic exchange separation technique has been applied in the determination of mercury in aqueous samples. The kinetics of the isotopic exchange reaction has been studied for various sample volumes. The effect of the flux perturbation caused by aqueous samples has been investigated for samples of various size and geometry in a central position in a well moderated heavy water reactor. The effect has been studied both theoretically and experimentally. The 'Thermos' code has been used in the calculations.

Determination of Mercury in Aqueous Samples by Means of Neutron Activation Analysis with an Account of Flux Disturbances

International Nuclear Information System (INIS)

Brune, D.; Jirlow, K.

1967-08-01

The technique of low temperature neutron irradiation combined with isotopic exchange separation technique has been applied in the determination of mercury in aqueous samples. The kinetics of the isotopic exchange reaction has been studied for various sample volumes. The effect of the flux perturbation caused by aqueous samples has been investigated for samples of various size and geometry in a central position in a well moderated heavy water reactor. The effect has been studied both theoretically and experimentally. The 'Thermos' code has been used in the calculations

Exchange Studies as Actor-Networks: Following Korean Exchange Students in Swedish Higher Education

Science.gov (United States)

Ahn, Song-ee

2011-01-01

This article explores how Korean exchange students organized their studies during exchange programs in Swedish higher education. For most students, the programs became a disordered period in relation to their education. The value of exchange studies seems mainly to be extra-curricular. Drawing upon actor network theory, the article argues that the…

Imaging of endogenous exchangeable proton signals in the human brain using frequency labeled exchange transfer imaging.

Science.gov (United States)

Yadav, Nirbhay N; Jones, Craig K; Hua, Jun; Xu, Jiadi; van Zijl, Peter C M

2013-04-01

To image endogenous exchangeable proton signals in the human brain using a recently reported method called frequency labeled exchange transfer (FLEX) MRI. As opposed to labeling exchangeable protons using saturation (i.e., chemical exchange saturation transfer, or CEST), FLEX labels exchangeable protons with their chemical shift evolution. The use of short high-power frequency pulses allows more efficient labeling of rapidly exchanging protons, while time domain acquisition allows removal of contamination from semi-solid magnetization transfer effects. FLEX-based exchangeable proton signals were detected in human brain over the 1-5 ppm frequency range from water. Conventional magnetization transfer contrast and the bulk water signal did not interfere in the FLEX spectrum. The information content of these signals differed from in vivo CEST data in that the average exchange rate of these signals was 350-400 s(-1) , much faster than the amide signal usually detected using direct saturation (∼30 s(-1) ). Similarly, fast exchanging protons could be detected in egg white in the same frequency range where amide and amine protons of mobile proteins and peptides are known to resonate. FLEX MRI in the human brain preferentially detects more rapidly exchanging amide/amine protons compared to traditional CEST experiments, thereby changing the information content of the exchangeable proton spectrum. This has the potential to open up different types of endogenous applications as well as more easy detection of rapidly exchanging protons in diaCEST agents or fast exchanging units such as water molecules in paracest agents without interference of conventional magnetization transfer contrast. Copyright © 2013 Wiley Periodicals, Inc.

Hibernation and gas exchange.

Science.gov (United States)

Milsom, William K; Jackson, Donald C

2011-01-01

Hibernation in endotherms and ectotherms is characterized by an energy-conserving metabolic depression due to low body temperatures and poorly understood temperature-independent mechanisms. Rates of gas exchange are correspondly reduced. In hibernating mammals, ventilation falls even more than metabolic rate leading to a relative respiratory acidosis that may contribute to metabolic depression. Breathing in some mammals becomes episodic and in some small mammals significant apneic gas exchange may occur by passive diffusion via airways or skin. In ectothermic vertebrates, extrapulmonary gas exchange predominates and in reptiles and amphibians hibernating underwater accounts for all gas exchange. In aerated water diffusive exchange permits amphibians and many species of turtles to remain fully aerobic, but hypoxic conditions can challenge many of these animals. Oxygen uptake into blood in both endotherms and ectotherms is enhanced by increased affinity of hemoglobin for O₂ at low temperature. Regulation of gas exchange in hibernating mammals is predominately linked to CO₂/pH, and in episodic breathers, control is principally directed at the duration of the apneic period. Control in submerged hibernating ectotherms is poorly understood, although skin-diffusing capacity may increase under hypoxic conditions. In aerated water blood pH of frogs and turtles either adheres to alphastat regulation (pH ∼8.0) or may even exhibit respiratory alkalosis. Arousal in hibernating mammals leads to restoration of euthermic temperature, metabolic rate, and gas exchange and occurs periodically even as ambient temperatures remain low, whereas body temperature, metabolic rate, and gas exchange of hibernating ectotherms are tightly linked to ambient temperature. © 2011 American Physiological Society.

Enabling Self-Monitoring Data Exchange in Participatory Medicine.

Science.gov (United States)

Lopez-Campos, Guillermo; Ofoghi, Bahadorreza; Martin-Sanchez, Fernando

2015-01-01

The development of new methods, devices and apps for self-monitoring have enabled the extension of the application of these approaches for consumer health and research purposes. The increase in the number and variety of devices has generated a complex scenario where reporting guidelines and data exchange formats will be needed to ensure the quality of the information and the reproducibility of results of the experiments. Based on the Minimal Information for Self Monitoring Experiments (MISME) reporting guideline we have developed an XML format (MISME-ML) to facilitate data exchange for self monitoring experiments. We have also developed a sample instance to illustrate the concept and a Java MISME-ML validation tool. The implementation and adoption of these tools should contribute to the consolidation of a set of methods that ensure the reproducibility of self monitoring experiments for research purposes.

Immobilisation in cement of ion exchange resins arising from the purification of reagents used for the decontamination of reactor circuits

International Nuclear Information System (INIS)

Howard, C.G.; Jolliffe, C.B.; Lee, D.J.

1988-09-01

The process developed previously for the immobilisation of Ion Exchange resin in cement has been scaled up to 200 litres. Large scale samples produced exhibit acceptable compressive strengths and dimensional stabilities. Destructive examination has shown that these samples are homogeneous and monolithic. A number of samples have been stored under water, this appears to have no detrimental effects on the dimensional stability and elastic modulus when compared to samples stored in air. Finally, a description of leach test work initiated using waste ion exchange resin treated with LOMI from the reactor at Winfrith is given. This work will be performed in accordance with the ISO leach test procedure. (author)

Technical studies on a composite groundwater sample from F- and H-Area

International Nuclear Information System (INIS)

Bibler, J.P.

1990-01-01

A composite sample of groundwater from F- and H-Areas was collected by Waste Management Tech and delivered to the Savannah River Laboratory to use in preliminary experiments that would test three remediation technologies under consideration. The three technologies are pH adjustment and filtration, decontamination with a strong acid ion exchange resin, and decontamination with a chelating ion exchange resin

Synthesis, structural characterization, and catalytic properties of tungsten-exchanged H-ZSM5

International Nuclear Information System (INIS)

Ding, Weiping; Meitzner, George D.; Marler, David O.; Iglesia, Enrique

2001-01-01

W-exchanged H-ZSM5 was prepared by sublimation of WCl6 at 673 K followed by hydrolysis of exchanged WClx species at 523 K. D2 exchange with residual OH groups showed that each W initially replaced about two zeolitic protons for W/Al ratios of 0.29 and 0.44, consistent with the formation of (WO2)2+ containing W6+ species bridging two cation exchange sites. As temperatures reached973 K during D2-OH exchange, these species reduced to (WO2)+ with the concurrent formation of one OD group. CH4 conversion turnover rates (per W) and C2-C1 2 selectivities are very similar to those observed on a Mo/H-ZSM5 sample with similar cation exchange level. As in the case of Mo/H-ZSM5, WOx/H-ZSM5 precursors are initially inactive in CH4 reactions, but they activate during induction with the concurrent evolution of CO, H2O, and an excess amount of H2. The reduction and carburization processes occurring during CH4 reactions and the structure of the exchanged WOx precursors was probed using in situ X-ray absorption spectroscopy (XAS). XAS studies confirmed the isolated initial nature of the exchanged WOx precursors after hydrolysis and dehydration and the formation of WCx clusters 0.6 nm in diameter during CH4 reactions at 973 K. The structural and catalytic resemblance between W- and Mo-exchanged H-ZSM5 is not unexpected, in view of chemical similarities between oxides or carbides of Mo and W. The synthesis of exchanged WOx precursors and their subsequent carburization during CH4 reactions, however, are more difficult than the corresponding processes for the MoOx counterparts. This may account for previous reports of lower CH4 reaction rates and aromatics selectivities on W/H-ZSM5 compared with those observed on Mo/H-ZSM5 and with those reported here for rigorously exchanged W/H-ZSM5

Ion exchangers in radioactive waste management: natural Iranian zeolites.

Science.gov (United States)

Nilchi, A; Maalek, B; Khanchi, A; Ghanadi Maragheh, M; Bagheri, A; Savoji, K

2006-01-01

Five samples of natural zeolites from different parts of Iran were chosen for this study. In order to characterize and determine their structures, X-ray diffraction and infrared spectrometry were carried out for each sample. The selective absorption properties of each zeolite were found by calculating the distribution coefficient (K(d)) of various simulated wastes which were prepared by spiking the radionuclides with (131)I, (99)Mo, (153)Sm, (140)La and (147)Nd. All the zeolite samples used in this study had extremely high absorption value towards (140)La; clinoptolite from Mianeh and analsite from Ghalehkhargoshi showed good absorption for (147)Nd; clinoptolite from Semnan and clinoptolite from Firozkoh showed high absorption for (153)Sm; mesolite from Arababad Tabas showed good absorption for (99)Mo; and finally mesolite from Arababad Tabas, clinoptolite from Semnan and clinoptolite from Firozkoh could be used to selectively absorb (131)I from the stimulated waste which was prepared. The natural zeolites chosen for these studies show a similar pattern to those synthetic ion exchangers in the literature and in some cases an extremely high selectivity towards certain radioactive elements. Hence the binary separation of radioactive elements could easily be carried out. Furthermore, these zeolites, which are naturally occurring ion exchangers, are viable economically and extremely useful alternatives in this industry.

Cobalt 60 cation exchange with mexican clays

International Nuclear Information System (INIS)

Nava Galve, R.G.

1993-01-01

Mexican clays can be used to remove radioactive elements from contaminated aqueous solutions. Cation exchange experiments were performed with 60 Co radioactive solution. In the present work the effect of contact time on the sorption of Co 2+ was studied. The contact time in hydrated montmorillonite was from 5 to 120 minutes and in dehydrated montmorillonite 5 to 1400 minutes. The Co 2+ uptake value was, in hydrated montmorillonite, between 0.3 to 0.85 m eq/g and in dehydrated montmorillonite, between 0.6 to 1.40 m eq/g. The experiments were done in a pH 5.1 to 5.7 and normal conditions. XRD patterns were used to characterize the samples. The crystallinity was determined by X-ray Diffraction and it was maintained before and after the cation exchange. DTA thermo grams showed the temperatures of the lost humidity and crystallization water. Finally, was observed that dehydrated montmorillonite adsorb more cobalt than hydrated montmorillonite. (Author)

Mastering Microsoft Exchange Server 2010

CERN Document Server

McBee, Jim

2010-01-01

A top-selling guide to Exchange Server-now fully updated for Exchange Server 2010. Keep your Microsoft messaging system up to date and protected with the very newest version, Exchange Server 2010, and this comprehensive guide. Whether you're upgrading from Exchange Server 2007 SP1 or earlier, installing for the first time, or migrating from another system, this step-by-step guide provides the hands-on instruction, practical application, and real-world advice you need.: Explains Microsoft Exchange Server 2010, the latest release of Microsoft's messaging system that protects against spam and vir

Tourism, real output and real effective exchange rate in Malaysia: a view from rolling sub-samples

OpenAIRE

Tang, Chor Foon

2011-01-01

The objective of this study is to examine the tourism-growth nexus for Malaysia with the cointegration and Granger causality tests. This study covers the monthly data from January 1989 to May 2010. The Johansen’s cointegration and the residuals-based test for cointegration with regime shift consistently suggest that tourist arrivals, real output, and real effective exchange rate in Malaysia are cointegrated. In terms of Granger causality, this study finds different sources of causality. In th...

Study of ion exchange equilibrium and determination of heat of ion exchange by ion chromatography

International Nuclear Information System (INIS)

Liu Kailu; Yang Wenying

1996-01-01

Ion chromatography using pellicularia ion exchange resins and dilute solution can be devoted to the study of ion exchange thermodynamics and kinetics. Ion exchange equilibrium equation was obtained, and examined by the experiments. Based on ion exchange equilibrium, the influence of eluent concentration and resin capacity on adjusted retention volumes was examined. The effect of temperature on adjusted retention volumes was investigated and heats of ion exchange of seven anions were determined by ion chromatography. The interaction between anions and skeleton structure of resins were observed

CACHE: an extended BASIC program which computes the performance of shell and tube heat exchangers

International Nuclear Information System (INIS)

Tallackson, J.R.

1976-03-01

An extended BASIC program, CACHE, has been written to calculate steady state heat exchange rates in the core auxiliary heat exchangers, (CAHE), designed to remove afterheat from High-Temperature Gas-Cooled Reactors (HTGR). Computationally, these are unbaffled counterflow shell and tube heat exchangers. The computational method is straightforward. The exchanger is subdivided into a user-selected number of lengthwise segments; heat exchange in each segment is calculated in sequence and summed. The program takes the temperature dependencies of all thermal conductivities, viscosities and heat capacities into account providing these are expressed algebraically. CACHE is easily adapted to compute steady state heat exchange rates in any unbaffled counterflow exchanger. As now used, CACHE calculates heat removal by liquid weight from high-temperature helium and helium mixed with nitrogen, oxygen and carbon monoxide. A second program, FULTN, is described. FULTN computes the geometrical parameters required as input to CACHE. As reported herein, FULTN computes the internal dimensions of the Fulton Station CAHE. The two programs are chained to operate as one. Complete user information is supplied. The basic equations, variable lists, annotated program lists, and sample outputs with explanatory notes are included

Sparse Power-Law Network Model for Reliable Statistical Predictions Based on Sampled Data

Directory of Open Access Journals (Sweden)

Alexander P. Kartun-Giles

2018-04-01

Full Text Available A projective network model is a model that enables predictions to be made based on a subsample of the network data, with the predictions remaining unchanged if a larger sample is taken into consideration. An exchangeable model is a model that does not depend on the order in which nodes are sampled. Despite a large variety of non-equilibrium (growing and equilibrium (static sparse complex network models that are widely used in network science, how to reconcile sparseness (constant average degree with the desired statistical properties of projectivity and exchangeability is currently an outstanding scientific problem. Here we propose a network process with hidden variables which is projective and can generate sparse power-law networks. Despite the model not being exchangeable, it can be closely related to exchangeable uncorrelated networks as indicated by its information theory characterization and its network entropy. The use of the proposed network process as a null model is here tested on real data, indicating that the model offers a promising avenue for statistical network modelling.

Development of techniques to dispose of the Windscale AGR heat exchangers

International Nuclear Information System (INIS)

Crossley, H.; Wakefield, J.R.

1991-01-01

In a gas-cooled nuclear power plant the gas side of the heat exchanger tubes becomes contaminated with radioactive deposits carried from the reactor in the coolant stream. In order to dispose of the heat exchangers in the safest and most cost-effective way during plant decommissioning, the deposits have to be removed. In situ chemical decontamination is considered to be the only viable method. This paper describes the research and development of chemical decontamination methods for the Windscale AGR heat exchangers, and the testing of a selected method on an in situ superheater. The research involved characterization of tube corrosion and radioactivity deposits, laboratory testing of chemical reagents on actual tube samples, and the provision and operation of a plant to apply the selected reagent. Disposal of radioactive effluent is an important consideration in chemical decontamination and in the present case was the major factor in determining the process

Progress in liquid ion exchangers

International Nuclear Information System (INIS)

Nakagawa, Genkichi

1974-01-01

Review is made on the extraction with anion exchangers and the extraction with liquid cation exchangers. On the former, explanation is made on the extraction of acids, the relation between anion exchange and the extraction of metals, the composition of the metallic complexes that are extracted, and the application of the extraction with anion exchangers to analytical chemistry. On the latter, explanation is made on the extraction of metals and its application to analytical chemistry. The extraction with liquid ion exchangers is suitable for the operation in chromatography, because the distribution of extracting agents into aqueous phase is small, and extraction equilibrium is quickly reached, usually within 1 to several minutes. The separation by means of anion exchangers is usually made from hydrochloric acid solution. For example, Brinkman et al. determined Rf values for more than 50 elements by thin layer chromatography. Tables are given for showing the structure of the liquid ion exchangers and the polymerized state of various amines. (Mori, K.)

Road Safety Peer Exchange for Tribal Governments : an RSPCB Peer Exchange

Science.gov (United States)

2014-12-01

This report provides a summary of the proceedings of the Road Safety Peer Exchange for Tribal : Governments held in Albuquerque, New Mexico on December 9th and 10th, 2014. The peer exchange : brought together safety practitioners from across the Unit...

Studies of cation exchange for the isolation and concentration of trace level components of complex aqueous mixtures

International Nuclear Information System (INIS)

Kaczvinsky, J.R. Jr.

1984-01-01

Trace level organic bases are concentrated from aqueous solution by cation exchange on a column of sulfonated macroreticular XAD-4 resin. Washing of the column with organic solvents removes neutrals and acids. Ammonia gas is introduced into the column prior to elution of the basic organics with either methanol or ether containing ammonia. After solvent evaporation, the concentrated sample is analyzed by gas chromatography. Recoveries of over 85% are found with at least one of the eluents for over 50 bases tested at levels < 1 ppm. Improved recoveries and reproducibility are seen over a simple ether extraction procedure. Samples of river water, shale oil process water, and supernatant from an agricultural chemical disposal pit are analyzed. Preliminary studies of functionalized poly(styrene-divinylbenzene)s, coated exchangers, and liquid ion exchangers as possible approaches to nuclear waste decontamination are performed

The Impact of Leader-member Exchange (LMX and Empowerment on Employee Voice Behavior

Directory of Open Access Journals (Sweden)

Chan Simon C. H.

2016-06-01

Full Text Available This study examines the impact of leader-member exchange (LMX and the moderating role of empowerment on employee voice behavior. A sample of 314 supervisor-subordinate dyadic exchanges was collected from a manufacturing firm in Mainland China. The results provided support the view that LMX and empowerment were both significantly associated with employee voice behavior. The positive relationship between LMX and employee voice behavior was stronger when employees received higher levels of empowerment. Theoretical and managerial implications of the research are discussed.

Ion exchange of strontium on synthetic hydroxyapatite

International Nuclear Information System (INIS)

Lazic, S.; Vukovic, Z.

1991-01-01

Adsorption of strontium ions on synthetic hydroxyapatite was examined using both batch and column methods. The apatite was prepared from aqueous solutions and characterized by standard analytical methods. The sample obtained had characteristics of well crystallized stoichiometric hydroxyapatite. The experimental data for sorption of strontium can be very well fitted with Langmuir's adsorption isotherm. It was found that sorption occurs by an ion exchange reaction between strontium ions in solution and calcium ions in apatite. (author) 14 refs.; 5 figs.; 1 tab

Exchange of Information in Tax Matters

OpenAIRE

Paweł Szwajdler

2017-01-01

The main aim of this paper is to present issues related to exchange of tax information. The author focuses on models of exchange of information and boundaries of obligations in reference to above-mentioned problems. Automatic exchange of information, spontaneous exchange of information and exchange of information on request are analysed in this work on the base of OECD Convention on Mutual Administrative Assistance in Tax Matters, Council Directive 2011/16 and OECD Model Agreement on Exchange...

Exchange bias energy in Co/Pt/IrMn multilayers with perpendicular and in-plane anisotropy

Energy Technology Data Exchange (ETDEWEB)

Czapkiewicz, M. [Department of Electronics, AGH University of Science and Technology, 30-059 Cracow (Poland)]. E-mail: czapkiew@agh.edu.pl; Stobiecki, T. [Department of Electronics, AGH University of Science and Technology, 30-059 Cracow (Poland); Rak, R. [Department of Electronics, AGH University of Science and Technology, 30-059 Cracow (Poland); Zoladz, M. [Department of Electronics, AGH University of Science and Technology, 30-059 Cracow (Poland); Dijken, S. van [CRANN and School of Physics, Trinity College, Dublin 2 (Ireland)

2007-09-15

The magnetization reversal process in perpendicularly biased [Pt/Co]{sub 3}/d{sub Pt} Pt/IrMn and in-plane biased Co/d{sub Pt} Pt/IrMn multilayers with 0nm=exchange bias field decreases monotonically with Pt insertion layer thickness, while its coercivity remains constant. The samples with perpendicular magnetic anisotropy, on the other hand, exhibit maximum exchange bias and minimum coercivity for d{sub Pt}=0.1nm. In both cases, the existence of large exchange bias fields correlates with a high domain density during magnetization reversal. The interface exchange coupling energy is larger for the in-plane biased films than for the perpendicularly biased multilayers.

3.5 Radiation stability of ion exchangers

International Nuclear Information System (INIS)

Marhol, M.

1976-01-01

The main knowledge is summed up of the radiation stability of ion exchangers. No basic changes occur in inorganic ion exchangers with the exception of the exchange capacity at doses of up to 10 9 rad. This also applies to coal-based ion exchangers. Tables are given showing the changes in specific volume, exchange capacity and weight of different types of organic ion exchangers in dependence on the radiation dose. The effects are discussed of the structure of organic cation and anion exchangers, polymeric strong basic anion exchangers, polycondensate anion exchangers and ion exchange membranes on their radiation stability. General experimental procedures are given for laboratory tests of the radiation stability of exchangers. (L.K.)

Local Road Safety Peer Exchange - Region 4 : An RSPCB Peer Exchange

Science.gov (United States)

2013-03-01

This report provides a summary of the proceedings of the Local Road Safety Peer Exchange held in Atlanta, Georgia on March 6th and 7th, 2013. The Federal Highway Administration (FHWA) sponsored the Peer Exchange in coordination with Region 4 Local Te...

Local Road Safety Peer Exchange - Region 7 : An RSPCB Peer Exchange

Science.gov (United States)

2012-05-01

This report provides a summary of the proceedings of the Local Road Safety Peer Exchange held in Denver, Colorado from May 31 to June 1, 2012. The Federal Highway Administration (FHWA) sponsored the Peer Exchange in coordination with Region 7 Local a...

Local Road Safety Peer Exchange - Region 1 : An RSPCB Peer Exchange

Science.gov (United States)

2012-10-01

This report provides a summary of the proceedings of the Local Road Safety Peer Exchange held in Piscataway, New Jersey October 10th and 11th, 2012. The Federal Highway Administration (FHWA) sponsored the Peer Exchange in coordination with Region 1 L...

Synthetic inorganic ion-exchange materials

International Nuclear Information System (INIS)

Abe, M.

1979-01-01

Exchange isotherms for hydrogen ion/alkali metal ions have been measured at 20 and 40 0 C, with a solution ionic strength of 0.1, in crystalline antimonic(V) acid as a cation-exchanger. The isotherms showed S-shaped curves for the systems of H + /Na + , H + /K + , H + /Rb + and H + /Cs + , but not for H + /Li + exchange. The selectivity coefficients (logarithm scale) vs equivalent fraction of alkali metal ions in the exchanger give linear functions for all systems studied. The selectivity sequences are shown. Overall and hypothetical (zero loading) thermodynamic equilibrium constants were evaluated for these ion-exchange reactions. (author)

Estimating the Distribution and Production of Microplankton in a Coastal Upwelling Front from the Cellular Content of Guanosine-5’-Triphosphate and Adenosine-5’-Triphosphate.

Science.gov (United States)

1981-09-01

through a microfine glass fiber tilter (Reeve Angel 984-H with a pore size of approximately 0.45 pnm). This...buffer (pH 7.7) in order to extract the nucleotides present in the water sample. The test tubes containing the extracts were labeled and stored frozen...into a series of disposable glass cuvettes (12x75mm) and placed in a test tube rack in an incubating water bath at 300 C. Each tube was allowed to

Institute for Advanced Pharmaceutical Sciences: Molecular Targets and Drug Screens to Combat Bioterrorism

Science.gov (United States)

2008-12-01

reaction volume with a 1.00 cm cuvette, and then calculating the rate of reaction (NADH/min) using the Beer –Lambert equation (AU=e·l· ACHTUNGTRENNUNG...10) Michel, K. H.; Boeck, L. D.; Hoehn, M. M.; Jones, N. D.; Chaney, M. O. The discovery, fermentation , isolation, and structure of antibiotic A...Antibiotic A-33853 was produced by aerobic fermentation from a new Streptomyces sp. that was isolated from an Illinois soil sample. Antibiotic A

Effect of spin structure transition in IrMn on the CoPd/IrMn perpendicular exchange biased system

Energy Technology Data Exchange (ETDEWEB)

Janjua, Muhammad Bilal; Guentherodt, Gernot [II. Physikalisches Institut A, RWTH Aachen University, Aachen (Germany)

2011-07-01

The exchange bias (EB) phenomenon is studied in MBE grown Pd(10 nm)/CoPd(x=8,16,30 nm)/IrMn(15 nm)/Pd(4 nm) samples, which exhibit a perpendicular anisotropy of Co22Pd78. These samples are field cooled along the out-of-plane direction and hysteresis loops are measured along both the out-of-plane and in-plane directions. It is observed that there is a transition temperature where the out-of-plane EB becomes greater than the in-plane EB. This behavior of EB is an evidence of the change in the spin structure of the given system, which is also revealed by the magnetization versus temperature measurements of the exchange biased and of the sole IrMn samples. It is found that with increasing temperature there is a spin structure transition in Ir25Mn75 (15nm) related to the 2Q to 3Q transition in the bulk, which is responsible for the increase in out-of-plane EB. A vertical shift in the hysteresis loop is also observed in these exchange biased samples at low temperatures (T<50 K).

Microsoft Exchange 2013 cookbook

CERN Document Server

Van Horenbeeck, Michael

2013-01-01

This book is a practical, hands-on guide that provides the reader with a number of clear, step-by-step exercises.""Microsoft Exchange 2013 Cookbook"" is targeted at network administrators who deal with the Exchange server in their day-to-day jobs. It assumes you have some practical experience with previous versions of Exchange (although this is not a requirement), without being a subject matter expert.

Plutonium metal exchange program : current status and statistical analysis

Energy Technology Data Exchange (ETDEWEB)

Tandon, L. (Lav); Eglin, J. L. (Judith Lynn); Michalak, S. E. (Sarah E.); Picard, R. R.; Temer, D. J. (Donald J.)

2004-01-01

The Rocky Flats Plutonium (Pu) Metal Sample Exchange program was conducted to insure the quality and intercomparability of measurements such as Pu assay, Pu isotopics, and impurity analyses. The Rocky Flats program was discontinued in 1989 after more than 30 years. In 2001, Los Alamos National Laboratory (LANL) reestablished the Pu Metal Exchange program. In addition to the Atomic Weapons Establishment (AWE) at Aldermaston, six Department of Energy (DOE) facilities Argonne East, Argonne West, Livermore, Los Alamos, New Brunswick Laboratory, and Savannah River are currently participating in the program. Plutonium metal samples are prepared and distributed to the sites for destructive measurements to determine elemental concentration, isotopic abundance, and both metallic and nonmetallic impurity levels. The program provides independent verification of analytical measurement capabilies for each participating facility and allows problems in analytical methods to be identified. The current status of the program will be discussed with emphasis on the unique statistical analysis and modeling of the data developed for the program. The discussion includes the definition of the consensus values for each analyte (in the presence and absence of anomalous values and/or censored values), and interesting features of the data and the results.

Determination of degradation conditions of exchange resins containing technetium

International Nuclear Information System (INIS)

Rivera S, A.; Monroy G, F.; Quintero P, E.

2014-10-01

The quantification of Tc-99 in spent exchange resins, coming from nuclear power plants, is indispensable to define their administration. The Tc-99 is a pure beta emitter of 210000 years of half-life, volatile and of a high mobility in water and soil. For this reason, the objective of this work is to establish a digestion method of ionic exchange resins containing technetium that retains more than 95% of this radioisotope. Mineralization tests were carried out of a resin Amberlite IRN-150 by means of an oxidation heat, in acid medium, varying the resin mass, the medium volume, the media type, the temperature and the digestion time. The digested samples were analyzed by gas chromatography to estimate the grade of their degradation. The 99m Tc was used as tracer to determine the technetium percentage recovered after mineralizing the resin. The digestion process depends on the temperature and the resin mass. At higher temperature better mineralization of samples and to greater resin mass to a constant temperature, less degradation of the resin. The spectra beta of the 99m Tc and 99 Tc are presented. (Author)

Choice of exchange rate regimes for African countries: Fixed or Flexible Exchange rate regimes?

OpenAIRE

Simwaka, Kisu

2010-01-01

The choice of an appropriate exchange rate regime has been a subject of ongoing debate in international economics. The majority of African countries are small open economies and thus where the choice of the exchange rate regime is an important policy issue. Aside from factors such as interest rates and inflation, the exchange rate is one of the most important determinants of a country’s relative level of economic health. For this reason, exchange rates are among the most watched analyzed and ...

Innovative heat exchangers

CERN Document Server

Scholl, Stephan

2018-01-01

This accessible book presents unconventional technologies in heat exchanger design that have the capacity to provide solutions to major concerns within the process and power-generating industries. Demonstrating the advantages and limits of these innovative heat exchangers, it also discusses micro- and nanostructure surfaces and micro-scale equipment, and introduces pillow-plate, helical and expanded metal baffle concepts. It offers step-by-step worked examples, which provide instructions for developing an initial configuration and are supported by clear, detailed drawings and pictures. Various types of heat exchangers are available, and they are widely used in all fields of industry for cooling or heating purposes, including in combustion engines. The market in 2012 was estimated to be U$ 42.7 billion and the global demand for heat exchangers is experiencing an annual growth of about 7.8 %. The market value is expected to reach U$ 57.9 billion in 2016, and approach U$ 78.16 billion in 2020. Providing a valua...

Upright heat exchanger

International Nuclear Information System (INIS)

Martoch, J.; Kugler, V.; Krizek, V.; Strmiska, F.

1988-01-01

The claimed heat exchanger is characteristic by the condensate level being maintained directly in the exchanger while preserving the so-called ''dry'' tube plate. This makes it unnecessary to build another pressure vessel into the circuit. The design of the heat exchanger allows access to both tube plates, which facilitates any repair. Another advantage is the possibility of accelerating the indication of leakage from the space of the second operating medium which is given by opening the drainage pipes of the lower bundle into the collar space and from there through to the indication pipe. The exchanger is especially suitable for deployment in the circuits of nuclear power plants where the second operating medium will be hot water of considerably lower purity than is that of the condensate. A rapid display of leakage can prevent any long-term penetration of this water into the condensate, which would result in worsening water quality in the entire secondary circuit of the nuclear power plant. (J.B.). 1 fig

Exchange Bias Optimization by Controlled Oxidation of Cobalt Nanoparticle Films Prepared by Sputter Gas Aggregation

Directory of Open Access Journals (Sweden)

Ricardo López Antón

2017-03-01

Full Text Available Porous films of cobalt nanoparticles have been obtained by sputter gas aggregation and controllably oxidized by air annealing at 100 °C for progressively longer times (up to more than 1400 h. The magnetic properties of the samples were monitored during the process, with a focus on the exchange bias field. Air annealing proves to be a convenient way to control the Co/CoO ratio in the samples, allowing the optimization of the exchange bias field to a value above 6 kOe at 5 K. The occurrence of the maximum in the exchange bias field is understood in terms of the density of CoO uncompensated spins and their degree of pinning, with the former reducing and the latter increasing upon the growth of a progressively thicker CoO shell. Vertical shifts exhibited in the magnetization loops are found to correlate qualitatively with the peak in the exchange bias field, while an increase in vertical shift observed for longer oxidation times may be explained by a growing fraction of almost completely oxidized particles. The presence of a hummingbird-like form in magnetization loops can be understood in terms of a combination of hard (biased and soft (unbiased components; however, the precise origin of the soft phase is as yet unresolved.

Australian Universities' Strategic Goals of Student Exchange and Participation Rates in Outbound Exchange Programmes

Science.gov (United States)

Daly, Amanda; Barker, Michelle

2010-01-01

International student exchange programmes are acknowledged as one aspect of a broader suite of internationalisation strategies aimed at enhancing students' intercultural understanding and competence. The decision to participate in an exchange programme is dependent on both individual and contextual factors such as student exchange policies and…

78 FR 46622 - Application of Topaz Exchange, LLC for Registration as a National Securities Exchange; Findings...

Science.gov (United States)

2013-08-01

... Exchange, LLC for Registration as a National Securities Exchange; Findings, Opinion, and Order of the... Registration as a National Securities Exchange (``Form 1 Application'') \\1\\ under Section 6 of the Securities... substantive, are consistent with the existing rules of other registered national securities exchanges, or are...

Increased CEST specificity for amide and fast-exchanging amine protons using exchange-dependent relaxation rate.

Science.gov (United States)

Zhang, Xiao-Yong; Wang, Feng; Xu, Junzhong; Gochberg, Daniel F; Gore, John C; Zu, Zhongliang

2018-02-01

Chemical exchange saturation transfer (CEST) imaging of amides at 3.5 ppm and fast-exchanging amines at 3 ppm provides a unique means to enhance the sensitivity of detection of, for example, proteins/peptides and neurotransmitters, respectively, and hence can provide important information on molecular composition. However, despite the high sensitivity relative to conventional magnetic resonance spectroscopy (MRS), in practice, CEST often has relatively poor specificity. For example, CEST signals are typically influenced by several confounding effects, including direct water saturation (DS), semi-solid non-specific magnetization transfer (MT), the influence of water relaxation times (T 1w ) and nearby overlapping CEST signals. Although several editing techniques have been developed to increase the specificity by removing DS, semi-solid MT and T 1w influences, it is still challenging to remove overlapping CEST signals from different exchanging sites. For instance, the amide proton transfer (APT) signal could be contaminated by CEST effects from fast-exchanging amines at 3 ppm and intermediate-exchanging amines at 2 ppm. The current work applies an exchange-dependent relaxation rate (R ex ) to address this problem. Simulations demonstrate that: (1) slowly exchanging amides and fast-exchanging amines have distinct dependences on irradiation powers; and (2) R ex serves as a resonance frequency high-pass filter to selectively reduce CEST signals with resonance frequencies closer to water. These characteristics of R ex provide a means to isolate the APT signal from amines. In addition, previous studies have shown that CEST signals from fast-exchanging amines have no distinct features around their resonance frequencies. However, R ex gives Lorentzian lineshapes centered at their resonance frequencies for fast-exchanging amines and thus can significantly increase the specificity of CEST imaging for amides and fast-exchanging amines. Copyright © 2017 John Wiley & Sons

Determination of americium and curium using ion-exchange in the nitric-acid-methanol medium for environmental analysis

International Nuclear Information System (INIS)

Holm, E.; Fukai, R.

1976-01-01

While transplutonic elements are only slightly sorbed to anion exchangers from hydrochloric or nitric acid media, the presence of alcohol enhances the anionic exchange of these elements, especially in nitric and sulfuric solutions. In the present work a method has been developed for determining americium and curium in environmental samples, on the basis of the difference between the sorption characteristics to anion exchangers in the acid-methanol system of these transplutonic elements and those of plutonium, polonium and thorium. The method also permits us to perform sequential determination of plutonium, when necessary

Role of Dividend of Power to Buy Shares in Companies in Indonesia Stock Exchange

Directory of Open Access Journals (Sweden)

Iskandar Muda

2017-06-01

Full Text Available This study aims to determine the role of the Purchasing Power Shares on manufacturing companies in Indonesia Stock Exchange Period 2014-2015. The variables used in this study as an Independent Variable Dividend and Purchasing Power Shares as Dependent Variables. Power Buy Stocks in this study was measured by the volume of stock sales every year. This research was conducted in Manufacturing company listed on the Indonesia Stock Exchange. The population of this study were 144 companies with purposive sampling as many as 19 of the Company's Manufacturing Company listed on the Indonesia Stock Exchange with the study of the 2014-2015 period in order to obtain 38 units of analysis. Data of this research are secondary data from the financial statements of 19 companies published in the Indonesia Stock Exchange. This research data processing method using the Test Statistics Deskribtif, Classical Assumption Test, Test Linear Regression using SPSS. The results of this study demonstrate that the role of the Dividend has significant influence on the Purchasing Power Shares in Manufacturing Company in Indonesia Stock Exchange (BEI.

Exchange rate regulation, the behavior of exchange rates, and macroeconomic stability in Brazil

Directory of Open Access Journals (Sweden)

Francisco Eduardo Pires de Souza

2011-12-01

Full Text Available In the last two decades an entirely new set of rules governing the foreign exchange transactions was established in Brazil, substituting for the framework inherited from the 1930s. Foreign exchange controls were dismantled and a floating exchange rate regime replaced different forms of peg. In this paper we argue that although successful by comparison to previous experiences, the current arrangement has important flaws that should be addressed. We discuss how it first led to high volatility and extremely high interest rates, which, when overcome, gave way to a long lasting appreciation of the real exchange rate with adverse consequences to industry.

Exchange bias behavior in Ni{sub 50.0}Mn{sub 35.5} In{sub 14.5} ribbons annealed at different temperatures

Energy Technology Data Exchange (ETDEWEB)

Sanchez, T. [Dept. de Fisica, Universidad de Oviedo, Calvo Sotelo s/n, 33007 Oviedo (Spain); Sato Turtelli, R.; Groessinger, R. [Institut fur Festkoerperphysik, Technische Universitaet Wien, Wiedner Hauptstr. 8-10, 1040 Vienna (Austria); Sanchez, M.L.; Santos, J.D.; Rosa, W.O.; Prida, V.M. [Dept. de Fisica, Universidad de Oviedo, Calvo Sotelo s/n, 33007 Oviedo (Spain); Escoda, Ll.; Sunol, J.J. [Campus de Montilivi, Universidad de Girona, edifici PII, Lluis Santalo s/n. 17003 Girona (Spain); Koledov, V. [Kotelnikov Institute of Radio Engineering and Electronics, RAS, Moscow 125009 (Russian Federation); Hernando, B., E-mail: grande@uniovi.es [Dept. de Fisica, Universidad de Oviedo, Calvo Sotelo s/n, 33007 Oviedo (Spain)

2012-10-15

Heusler alloy Ni{sub 50.0}Mn{sub 35.5}In{sub 14.5} ribbons were prepared by melt-spinning technique. Several short time annealings were carried out in order to enhance the exchange bias effect in this alloy ribbon. The magnetic transition temperature increases with the annealing, compared to the as-spun sample, however no significant differences in respective Curie temperatures were observed for austenite and martensite phases in such annealed samples. Exchange bias effect is observed at low temperatures for all samples and practically vanishes at 60 K for the as-spun sample, whereas for the annealed ribbons it vanishes at 100 K.

A multi-species exchange model for fully fluctuating polymer field theory simulations.

Science.gov (United States)

Düchs, Dominik; Delaney, Kris T; Fredrickson, Glenn H

2014-11-07

Field-theoretic models have been used extensively to study the phase behavior of inhomogeneous polymer melts and solutions, both in self-consistent mean-field calculations and in numerical simulations of the full theory capturing composition fluctuations. The models commonly used can be grouped into two categories, namely, species models and exchange models. Species models involve integrations of functionals that explicitly depend on fields originating both from species density operators and their conjugate chemical potential fields. In contrast, exchange models retain only linear combinations of the chemical potential fields. In the two-component case, development of exchange models has been instrumental in enabling stable complex Langevin (CL) simulations of the full complex-valued theory. No comparable stable CL approach has yet been established for field theories of the species type. Here, we introduce an extension of the exchange model to an arbitrary number of components, namely, the multi-species exchange (MSE) model, which greatly expands the classes of soft material systems that can be accessed by the complex Langevin simulation technique. We demonstrate the stability and accuracy of the MSE-CL sampling approach using numerical simulations of triblock and tetrablock terpolymer melts, and tetrablock quaterpolymer melts. This method should enable studies of a wide range of fluctuation phenomena in multiblock/multi-species polymer blends and composites.

Searching for long-range dependence in real effective exchange rate: towards parity?

Directory of Open Access Journals (Sweden)

André M. Marques

2015-12-01

Full Text Available Abstract After the widespread adoption of flexible exchange rate regime since 1973 the volatility of the exchange rate has increased, as a consequence of greater trade openness and financial integration. As a result, it has become difficult to find evidence of the purchasing power parity hypothesis (PPP. This study investigates the possibility of a fall in the persistence of the real exchange rate as a consequence of the financial and commercial integration by employing monthly real effective exchange rate dataset provided by the International Monetary Fund (IMF. Beginning with an exploratory data analysis in the frequency domain, the fractional coefficient d was estimated employing the bias-reduced estimator on a sample of 20 countries over the period ranging from 1975 to 2011. As the main novelty, this study applies a bias-reduced log-periodogram regression estimator instead of the traditional method proposed by GPH which eliminates the first and higher orders biases by a data-dependent plug-in method for selecting the number of frequencies to minimize asymptotic mean-squared error (MSE. Additionally, this study also estimates a moving window of fifteen years to observe the path of the fractional coefficient in each country. No evidence was found of a statistically significant change in the persistence of the real exchange rate.

Preoperative gender differences in pulmonary gas exchange in morbidly obese subjects.

Science.gov (United States)

Zavorsky, Gerald S; Christou, Nicolas V; Kim, Do Jun; Carli, Franco; Mayo, Nancy E

2008-12-01

Morbidly obese men may have poorer pulmonary gas exchange compared to morbidly obese women (see Zavorsky et al., Chest 131:362-367, 2007). The purpose was to compare pulmonary gas exchange in morbidly obese men and women at rest and throughout exercise. Twenty-five women (age=38+/-10 years, 164+/-7 cm, body mass index or BMI = 51+/-7 kg/m(2), peak oxygen consumption or VO(2peak)=2.0+/-0.4 l/min) and 17 men (age=43+/-9 years, 178+/-7 cm, BMI=50+/-10 kg/m(2), VO(2peak)=2.6+/-0.8 l/min) were recruited to perform a graded exercise test on a cycle ergometer with temperature-corrected arterial blood-gas samples taken at rest and every minute of exercise, including peak exercise. At rest, women were 98% predicted for pulmonary diffusion compared to 88% predicted in men. At rest, women had better pulmonary gas exchange compared to the men which was related to women having a lower waist-to-hip ratio (WHR; por=25 mmHg) at peak exercise, but 75% of the subjects showed inadequate compensatory hyperventilation at peak exercise (arterial carbon dioxide pressure >35 mmHg), and both were not different between genders. At rest, morbidly obese men have poorer pulmonary gas exchange and pulmonary diffusion compared to morbidly obese women. The better gas exchange in women is related to the lower WHR in the women. During exercise, few subjects showed disturbances in pulmonary gas exchange despite demonstrating poor compensatory hyperventilation at peak exercise.

Rapid oxygen exchange across the leaves of Littorella uniflora provides tolerance to sediment anoxia

DEFF Research Database (Denmark)

Møller, Claus Lindskov; Jensen, Kaj Sand

2012-01-01

1. Littorella uniflora and Lobelia dortmanna are prominent small rosette species in nutrient-poor, soft-water lakes because of efficient root exchange of CO2 and O2. We hypothesise that higher gas exchange across the leaves of L.similar to uniflora than of L.similar to dortmanna ensures O2 uptake...... from water and underlies its greater tolerance to sediment anoxia following organic enrichment. 2. We studied plant response to varying sediment O2 demand and biogeochemistry by measuring photosynthesis, gas exchange across leaves and O2 dynamics in plants during long-term laboratory and field studies....... Frequent non-destructive sampling of sediment pore water was used to track changes in sediment biogeochemistry. 3. Addition of organic matter triggered O2 depletion and accumulation of , Fe2+ and CO2 in sediments. Gas exchange across leaf surfaces was 1316 times higher for L.similar to uniflora than for L...

Comparison between conventional heat exchanger performance and an heat pipes exchanger

International Nuclear Information System (INIS)

Souza, J.R.G. de; Rocha, N.R.

1989-01-01

The thermal performance of conventional compact heat exchanger and of exchanger with heat pipes are simulated using a digital computer, for equal volumes and the same process conditions. The comparative analysis is depicted in graphs that indicate which of the situations each equipment is more efficient. (author)

Effect of shell thickness on the exchange bias blocking temperature and coercivity in Co-CoO core-shell nanoparticles

Science.gov (United States)

Thomas, S.; Reethu, K.; Thanveer, T.; Myint, M. T. Z.; Al-Harthi, S. H.

2017-08-01

The exchange bias blocking temperature distribution of naturally oxidized Co-CoO core-shell nanoparticles exhibits two distinct signatures. These are associated with the existence of two magnetic entities which are responsible for the temperature dependence of an exchange bias field. One is from the CoO grains which undergo thermally activated magnetization reversal. The other is from the disordered spins at the Co-CoO interface which exhibits spin-glass-like behavior. We investigated the oxide shell thickness dependence of the exchange bias effect. For particles with a 3 nm thick CoO shell, the predominant contribution to the temperature dependence of exchange bias is the interfacial spin-glass layer. On increasing the shell thickness to 4 nm, the contribution from the spin-glass layer decreases, while upholding the antiferromagnetic grain contribution. For samples with a 4 nm CoO shell, the exchange bias training was minimal. On the other hand, 3 nm samples exhibited both the training effect and a peak in coercivity at an intermediate set temperature Ta. This is explained using a magnetic core-shell model including disordered spins at the interface.

A spin exchange model for singlet fission

Science.gov (United States)

Yago, Tomoaki; Wakasa, Masanobu

2018-03-01

Singlet fission has been analyzed with the Dexter model in which electron exchange occurs between chromophores, conserving the spin for each electron. In the present study, we propose a spin exchange model for singlet fission. In the spin exchange model, spins are exchanged by the exchange interaction between two electrons. Our analysis with simple spin functions demonstrates that singlet fission is possible by spin exchange. A necessary condition for spin exchange is a variation in exchange interactions. We also adapt the spin exchange model to triplet fusion and triplet energy transfer, which often occur after singlet fission in organic solids.

Effect of borax on immune cell proliferation and sister chromatid exchange in human chromosomes

OpenAIRE

Pongsavee Malinee

2009-01-01

Abstract Background Borax is used as a food additive. It becomes toxic when accumulated in the body. It causes vomiting, fatigue and renal failure. Methods The heparinized blood samples from 40 healthy men were studied for the impact of borax toxicity on immune cell proliferation (lymphocyte proliferation) and sister chromatid exchange in human chromosomes. The MTT assay and Sister Chromatid Exchange (SCE) technic were used in this experiment with the borax concentrations of 0.1, 0.15, 0.2, 0...

Ion-exchange chromatographic protein refolding

NARCIS (Netherlands)

Freydell, E.; Wielen, van der L.; Eppink, M.H.M.; Ottens, M.

2010-01-01

The application of ion-exchange (IEX) chromatography to protein refolding (IExR) has been successfully proven, as supported by various studies using different model proteins, ion-exchange media and flow configurations. Ion-exchange refolding offers a relatively high degree of process

Sample displacement chromatography as a method for purification of proteins and peptides from complex mixtures

Science.gov (United States)

Gajdosik, Martina Srajer; Clifton, James; Josic, Djuro

2012-01-01

Sample displacement chromatography (SDC) in reversed-phase and ion-exchange modes was introduced approximately twenty years ago. This method takes advantage of relative binding affinities of components in a sample mixture. During loading, there is a competition among different sample components for the sorption on the surface of the stationary phase. SDC was first used for the preparative purification of proteins. Later, it was demonstrated that this kind of chromatography can also be performed in ion-exchange, affinity and hydrophobic-interaction mode. It has also been shown that SDC can be performed on monoliths and membrane-based supports in both analytical and preparative scale. Recently, SDC in ion-exchange and hydrophobic interaction mode was also employed successfully for the removal of trace proteins from monoclonal antibody preparations and for the enrichment of low abundance proteins from human plasma. In this review, the principals of SDC are introduced, and the potential for separation of proteins and peptides in micro-analytical, analytical and preparative scale is discussed. PMID:22520159

Factors Influencing Electronic Clinical Information Exchange in Small Medical Group Practices

Science.gov (United States)

Kralewski, John E.; Zink, Therese; Boyle, Raymond

2012-01-01

Purpose: The purpose of this study was to identify the organizational factors that influence electronic health information exchange (HIE) by medical group practices in rural areas. Methods: A purposive sample of 8 small medical group practices in 3 experimental HIE regions were interviewed to determine the extent of clinical information exchange…

Fluoride Thin Films: from Exchange Bias to Multferroicity

Science.gov (United States)

Johnson, Trent A.

This dissertation concerns research into the growth and characterization fluoride thin films by molecular beam epitaxy. After a discussion of relevant background material and experimental procedures in the first two chapters, we study exchange bias in magnetic multilayers incorporating the uniaxial antiferromagnet FeF2, grown to varying thicknesses, sandwiched between ferromagnetic Co layers with fixed thicknesses of 5 and 20 nm. Several bilayers with only the 20 nm thick Co layer were grown for comparative study. The samples were grown on Al2O3 (112¯0) substrates at room temperature. In-situ RHEED and x-ray diffraction indicated the films were polycrystalline. The films were determined to have low surface and interlayer roughness, as determined by AFM and x-ray reflectivity. After field-cooling to below the Neel temperature of FeF2 in a magnetic field of 1 kOe, magnetic hysteresis loops were measured as a function of temperature. We found that both layers had a negative exchange bias, with the exchange bias of the thinner layer larger than that of the thicker layer. In addition, the coercivity below the blocking temperature TB of the thinner layer was significantly larger than that of the thick layer, even though the coercivity of the two layers was the same for T > TB. The exchange bias effect, manifested by a shift in these hysteresis loops, showed a strong dependence on the thickness of the antiferromagnet. Anisotropic magnetoresistance measurements provided additional insight into the magnetization reversal mechanism within the ferromagnets. The thickness dependent exchange anisotropy of trilayer and bilayer samples is explained by adapting a random field model to the antiferromagnet/ferromagnet interface. Finally, We investigate the temperature dependent growth, as well as the magnetic and ferroelectric properties of thin films of the multiferroic compounds BaMF4, where M = Fe, Co, Ni. The films were grown to thicknesses of 50 or 100 nm on single crystal Al2

31 CFR 500.325 - National securities exchange.

Science.gov (United States)

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false National securities exchange. 500.325... Definitions § 500.325 National securities exchange. The term national securities exchange shall mean an exchange registered as a national securities exchange under section 6 of the Securities Exchange Act of...

31 CFR 515.325 - National securities exchange.

Science.gov (United States)

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false National securities exchange. 515.325... Definitions § 515.325 National securities exchange. The term national securities exchange shall mean an exchange registered as a national securities exchange under section 6 of the Securities Exchange Act of...

An Empirical Investigation into Exchange Rate Regime Choice and Exchange Rate Volatility

OpenAIRE

Helge Berger; Jan-Egbert Sturm; Jakob de Haan

2000-01-01

We test a simple model of exchange rate regime choice with data for 65 non-OECD countries covering the period 1980-94. We find that the variance of output at home and in potential target c ountries as well as the correlation between home and foreign real activity are powerful and robust predictors of exchange rate regime choice. Surprisingly, a more volatile foreign economy can be an argument in favor of a fixed exchange rate regime once similarities in the business cycle are taken into accou...

Experimental test of exchange degeneracy in hypercharge exchange reactions

International Nuclear Information System (INIS)

Moffeit, K.C.

1978-10-01

Two pairs of line-reversed reactions π + P → K + Σ + , K - p → π - Σ + and π + p → K + Y* + (1385), K - p → π - Y* + (1385) provide an experimental test of exchange degeneracy in hypercharge exchange reactions. From their study it is concluded that in contrast to the lower energy data, the 11.5 results for the two pairs of reactions are consistent with exchange degeneracy predictions for both helicity-flip and nonflip amplitudes. The Y(1385) decay angular distributions indicate that the quark model and Stodolsky--Sakurai predictions are in agreement with the main features of the data. However, small violations are observed at small momentum transfer. While the Y(1385) vertex is helicity-flip dominated, the nonvanishing of T/sub 3/2 - 1/2/ and T/sub -3/2 1/2/ suggests some finite helicity nonflip contribution in the forward direction. 23 references

Sm isotope composition and Sm/Eu ratio determination in an irradiated 153Eu sample by ion exchange chromatography-quadrupole inductively coupled plasma mass spectrometry combined with double spike isotope dilution technique

International Nuclear Information System (INIS)

Bourgeois, M.; Isnard, H.; Gourgiotis, A.; Stadelmann, G.; Gautier, C.; Mialle, S.; Nonell, A.; Chartier, F.

2011-01-01

Within the framework of the research undertaken by the French Atomic Energy Commission on transmutation of long-lived radionuclides, targets of highly enriched actinides and fission products were irradiated in the fast neutron reactor Phenix. Precise and accurate measurements of the isotopic and elemental composition of the enriched elements are therefore required. In order to obtain the uncertainties of several per mil and to reduce handling time and exposure to analyst on radioactive material, the on-line coupling of ion exchange chromatography with quadrupole inductively coupled plasma mass spectrometry has been associated with the technique of the double spike isotope dilution. We present in this paper the results obtained on an irradiated sample of Europium oxide powder (enriched at 99.13% in 153 Eu). After irradiation of around 5 mg of Eu 2 O 3 powder the theoretical calculations predict the formation of several micrograms of gadolinium and samarium isotopes. In relation to the very high activity of the sample after irradiation and the very low quantity of Sm formed, the on-line ion exchange chromatography separation of Gd, Sm and Eu before Sm isotope ratio measurements has been developed for the quantification of the 152 Sm/ 153 Eu ratio. These on-line measurements were associated with the double spike isotope dilution technique after calibration of a 147 Sm/ 151 Eu spike solution. The external reproducibility of Sm isotopic ratios was determined to be around 0.5% (2 σ) resulting in a final uncertainty on the 152 Sm/ 153 Eu ratio of around 1% (2 σ). These on-line measurements present therefore a robust and high-throughput alternative to the thermal-ionisation mass spectrometry technique used so far in combination with off-line chromatographic separation, particularly in nuclear applications where characterisation of high activity sample solutions is required. (authors)

Ion exchange technology assessment report

International Nuclear Information System (INIS)

Duhn, E.F.

1992-01-01

In the execution of its charter, the SRS Ion Exchange Technology Assessment Team has determined that ion exchange (IX) technology has evolved to the point where it should now be considered as a viable alternative to the SRS reference ITP/LW/PH process. The ion exchange media available today offer the ability to design ion exchange processing systems tailored to the unique physical and chemical properties of SRS soluble HLW's. The technical assessment of IX technology and its applicability to the processing of SRS soluble HLW has demonstrated that IX is unquestionably a viable technology. A task team was chartered to evaluate the technology of ion exchange and its potential for replacing the present In-Tank Precipitation and proposed Late Wash processes to remove Cs, Sr, and Pu from soluble salt solutions at the Savannah River Site. This report documents the ion exchange technology assessment and conclusions of the task team

Lead isotope analyses of standard rock samples

International Nuclear Information System (INIS)

Koide, Yoshiyuki; Nakamura, Eizo

1990-01-01

New results on lead isotope compositions of standard rock samples and their analytical procedures are reported. Bromide form anion exchange chromatography technique was adopted for the chemical separation lead from rock samples. The lead contamination during whole analytical procedure was low enough to determine lead isotope composition of common natural rocks. Silica-gel activator method was applied for emission of lead ions in the mass spectrometer. Using the data reduction of 'unfractionated ratios', we obtained good reproducibility, precision and accuracy on lead isotope compositions of NBS SRM. Here we present new reliable lead isotope compositions of GSJ standard rock samples and USGS standard rock, BCR-1. (author)

Introduction to solid supported membrane based electrophysiology.

Science.gov (United States)

Bazzone, Andre; Costa, Wagner Steuer; Braner, Markus; Călinescu, Octavian; Hatahet, Lina; Fendler, Klaus

2013-05-11

The electrophysiological method we present is based on a solid supported membrane (SSM) composed of an octadecanethiol layer chemisorbed on a gold coated sensor chip and a phosphatidylcholine monolayer on top. This assembly is mounted into a cuvette system containing the reference electrode, a chlorinated silver wire. After adsorption of membrane fragments or proteoliposomes containing the membrane protein of interest, a fast solution exchange is used to induce the transport activity of the membrane protein. In the single solution exchange protocol two solutions, one non-activating and one activating solution, are needed. The flow is controlled by pressurized air and a valve and tubing system within a faraday cage. The kinetics of the electrogenic transport activity is obtained via capacitive coupling between the SSM and the proteoliposomes or membrane fragments. The method, therefore, yields only transient currents. The peak current represents the stationary transport activity. The time dependent transporter currents can be reconstructed by circuit analysis. This method is especially suited for prokaryotic transporters or eukaryotic transporters from intracellular membranes, which cannot be investigated by patch clamp or voltage clamp methods.

Study of the influence of Nb buffer layer on the exchange coupling induced at the Co/IrMn interface

Energy Technology Data Exchange (ETDEWEB)

Merino, I.L.C., E-mail: isabel5cas@gmail.com [Centro Brasileiro de Pesquisas Físicas, Rio de Janeiro 22290-180 (Brazil); Figueiredo, L.C. [Instituto de Física, Universidade de Brasília, Brasília 70910-900 (Brazil); Passamani, E.C.; Nascimento, V.P. [Departamento de Física, Universidade Federal do Espírito Santo, Vitória 29075-910 (Brazil); Pelegrini, F. [Instituto de Física, Universidade Federal de Goiás, Goiânia 74560-900 (Brazil); Baggio Saitovitch, E. [Centro Brasileiro de Pesquisas Físicas, Rio de Janeiro 22290-180 (Brazil)

2017-06-15

Highlights: • Nb buffer layer favors smooth/rough Co/IrMn interfaces, depending on its thickness. • Double and single-like hysteresis loop features depend on the Nb thickness. • Co uniaxial anisotropy induced exchange-bias in as-deposited sample. • Uniaxial and exchange-bias anisotropy directions depend on the Nb thickness. • Thicker Nb favors non-collinear anisotropies, while thinner Nb favors collinear. - Abstract: Hybrid Nb(t{sub Nb})/Co(10 nm)/IrMn(15 nm)/Nb(10 nm) heterostructured materials were prepared by DC Magnetron Sputtering and systematically studied by X-ray, magnetization and ferromagnetic resonance techniques. For thinner Nb buffer layer (≤10 nm), it was found that there is an inter-diffusion at Co/IrMn interface, which favors double-like hysteresis loop. For thicker Nb layers, however, a gradual transition from double to single-like hysteresis loops is observed and it is associated with the reduction of the Nb roughness, which also enhances the exchange coupling at the Co/IrMn interface. Nb grown on IrMn layer induces the formation of an NbIrMn alloy layer, while no evidence of inter-diffusion at the Co/Nb interface is observed. For rougher Nb buffer layers (t{sub Nb} < 50 nm), exchange bias and Co uniaxial anisotropies are pointing at the same direction (β∼zero), but for smoother Nb buffer layer (t{sub Nb} = 50 nm) a β angle of 150{sup o} is found. Exchange bias effect was measured in as-prepared and in field-cooled samples; being its presence, in as-prepared sample, attributed to the unidirectional anisotropy of the Co layer (its intensity is modified in case of sample with a CoIrMn alloy layer). Considering that the Si/Nb/Co/IrMn interfaces have different β values (t{sub Nb} = 35 and 50 nm), a study of the influence of magnetization direction, governed by exchange-biased layers, on superconducting properties of Nb films can be successfully done in this hybrid system.

Custom, contract, and kidney exchange.

Science.gov (United States)

Healy, Kieran; Krawiec, Kimberly D

2012-01-01

In this Essay, we examine a case in which the organizational and logistical demands of a novel form of organ exchange (the nonsimultaneous, extended, altruistic donor (NEAD) chain) do not map cleanly onto standard cultural schemas for either market or gift exchange, resulting in sociological ambiguity and legal uncertainty. In some ways, a NEAD chain resembles a form of generalized exchange, an ancient and widespread instance of the norm of reciprocity that can be thought of simply as the obligation to “pay it forward” rather than the obligation to reciprocate directly with the original giver. At the same time, a NEAD chain resembles a string of promises and commitments to deliver something in exchange for some valuable consideration--that is, a series of contracts. Neither of these salient "social imaginaries" of exchange--gift giving or formal contract--perfectly meets the practical demands of the NEAD system. As a result, neither contract nor generalized exchange drives the practice of NEAD chains. Rather, the majority of actual exchanges still resemble a simpler form of exchange: direct, simultaneous exchange between parties with no time delay or opportunity to back out. If NEAD chains are to reach their full promise for large-scale, nonsimultaneous organ transfer, legal uncertainties and sociological ambiguities must be finessed, both in the practices of the coordinating agencies and in the minds of NEAD-chain participants. This might happen either through the further elaboration of gift-like language and practices, or through a creative use of the cultural form and motivational vocabulary, but not necessarily the legal and institutional machinery, of contract.

New type fuel exchange system

International Nuclear Information System (INIS)

Meshii, Toshio; Maita, Yasushi; Hirota, Koichi; Kamishima, Yoshio.

1988-01-01

When the reduction of the construction cost of FBRs is considered from the standpoint of the machinery and equipment, to make the size small and to heighten the efficiency are the assigned mission. In order to make a reactor vessel small, it is indispensable to decrease the size of the equipment for fuel exchange installed on the upper part of a core. Mitsubishi Heavy Industries Ltd. carried out the research on the development of a new type fuel exchange system. As for the fuel exchange system for FBRs, it is necessary to change the mode of fuel exchange from that of LWRs, such as handling in the presence of chemically active sodium and inert argon atmosphere covering it and handling under heavy shielding against high radiation. The fuel exchange system for FBRs is composed of a fuel exchanger which inserts, pulls out and transfers fuel and rotary plugs. The mechanism adopted for the new type fuel exchange system that Mitsubishi is developing is explained. The feasibility of the mechanism on the upper part of a core was investigated by water flow test, vibration test and buckling test. The design of the mechanism on the upper part of the core of a demonstration FBR was examined, and the new type fuel exchange system was sufficiently applicable. (Kako, I.)

Transition from reversible to irreversible magnetic exchange-spring processes in antiferromagnetically exchange-coupled hard/soft/hard trilayer structures

International Nuclear Information System (INIS)

Wang Xiguang; Guo Guanghua; Zhang Guangfu

2011-01-01

The demagnetization processes of antiferromagnetically exchange-coupled hard/soft/hard trilayer structures have been studied based on the discrete one-dimensional atomic chain model and the linear partial domain-wall model. It is found that, when the magnetic anisotropy of soft layer is taken into account, the changes of the soft layer thickness and the interfacial exchange coupling strength may lead a transition of demagnetization process in soft layer from the reversible to the irreversible magnetic exchange-spring process. For the trilayer structures with very thin soft layer, the demagnetization process exhibits typical reversible exchange-spring behavior. However, as the thickness of soft layer is increased, there is a crossover point t c , after which the process becomes irreversible. Similarly, there is also a critical interfacial exchange coupling constant A sh c , above which the exchange-spring process is reversible. When A sh sh c , the irreversible exchange-spring process is achieved. The phase diagram of reversible and irreversible exchange-spring processes is mapped in the plane of the interfacial exchange coupling A sh and soft layer thickness N s . - Research highlights: → A differing magnetic exchange-spring process is found in antiferromagnetically exchange-coupled hard/soft/hard trilayers if the magnetic anisotropy of the soft layers is taken into account. → The change of the soft layer thickness may lead to a transition of demagnetization process in soft layer from the reversible to the irreversible exchange-spring process. → The change of the soft-hard interfacial exchange coupling strength may lead a transition of demagnetization process in soft layer from the reversible to the irreversible exchange-spring process. → The phase diagram of reversible and irreversible exchange-spring processes is mapped in the plane of the interfacial exchange coupling and soft layer thickness.

Sampling and characterization of spent exchange resins of Atucha I nuclear power plant

International Nuclear Information System (INIS)

Varani, Jose L.; Cernadas, D.; Iglesias, Alberto M.; Raffo Calderon, Maria del C.

2004-01-01

The present storage facilities for spent resins in Atucha I NPP would be full within the next 5 years, accordingly some tasks are being planned to conditioning these waste and so generate enough storage capacity for the remaining life of the plant. Among this tasks is the characterization of spent resins that has several objectives: to know their chemical and radiochemical composition; the homogeneity of these parameters in the total volume of spent resins; the existence or not of compact zones; the proportion of 'crud'; the breakage degree of the micro-spheres; etc. The first step was to analyse the criterion to follow for sampling resins in the storage deposit of 40 m 3 . In order to take some samples from different points, a special device was required. It had to be introduced closed in the resin bed, opened to take the sample and then closed again to return to the surface. A device used in cereal industry for sampling silos to different depths was modified in its internal capacity for reducing operator dose and increasing the length of rod in order to reaching the bottom of the pit. The device was tested in cold mock up before to taking actual samples. Active resins samples, five in total up to now, were taken from deposit to different depths and kept in lead containers. After analysing the samples, the following average results were extracted: 1.7 x 10 5 Bq/g of Co-60, 9.7 x 10 5 Bq/g of Cs-137 and 774 Bq/g of total alpha, which corresponds to intermediate activity waste. The differences between the values of activity of the different samples are of up to 310 % for Co-60 and of up to 788 % for the Cs-137 what indicates a great inhomogeneity. The direct observation of resin grains, placed in a transparent glass burette, did not demonstrate an important proportion of broken or divided resins. (author)

Indiana Health Information Exchange

Science.gov (United States)

The Indiana Health Information Exchange is comprised of various Indiana health care institutions, established to help improve patient safety and is recognized as a best practice for health information exchange.

Hydrogen exchange during cell-free incorporation of deuterated amino acids and an approach to its inhibition

Energy Technology Data Exchange (ETDEWEB)

Tonelli, Marco; Singarapu, Kiran K. [University of Wisconsin-Madison, National Magnetic Resonance Facility at Madison (NMRFAM), Department of Biochemistry (United States); Makino, Shin-ichi; Sahu, Sarata C.; Matsubara, Yuko [University of Wisconsin-Madison, Center for Eukaryotic Structural Genomics (CESG), Department of Biochemistry (United States); Endo, Yaeta [Ehime University, Cell-Free Science and Technology Research Center (Japan); Kainosho, Masatsune [Tokyo Metropolitan University, Center for Priority Areas (Japan); Markley, John L., E-mail: markley@nmrfam.wisc.edu [University of Wisconsin-Madison, National Magnetic Resonance Facility at Madison (NMRFAM), Department of Biochemistry (United States)

2011-12-15

Perdeuteration, selective deuteration, and stereo array isotope labeling (SAIL) are valuable strategies for NMR studies of larger proteins and membrane proteins. To minimize scrambling of the label, it is best to use cell-free methods to prepare selectively labeled proteins. However, when proteins are prepared from deuterated amino acids by cell-free translation in H{sub 2}O, exchange reactions can lead to contamination of {sup 2}H sites by {sup 1}H from the solvent. Examination of a sample of SAIL-chlorella ubiquitin prepared by Escherichia coli cell-free synthesis revealed that exchange had occurred at several residues (mainly at Gly, Ala, Asp, Asn, Glu, and Gln). We present results from a study aimed at identifying the exchanging sites and level of exchange and at testing a strategy for minimizing {sup 1}H contamination during wheat germ cell-free translation of proteins produced from deuterated amino acids by adding known inhibitors of transaminases (1 mM aminooxyacetic acid) and glutamate synthetase (0.1 mM l-methionine sulfoximine). By using a wheat germ cell-free expression system, we produced [U-{sup 2}H, {sup 15}N]-chlorella ubiquitin without and with added inhibitors, and [U-{sup 15}N]-chlorella ubiquitin as a reference to determine the extent of deuterium incorporation. We also prepared a sample of [U-{sup 13}C, {sup 15}N]-chlorella ubiquitin, for use in assigning the sites of exchange. The added inhibitors did not reduce the protein yield and were successful in blocking hydrogen exchange at C{sup {alpha}} sites, with the exception of Gly, and at C{sup {beta}} sites of Ala. We discovered, in addition, that partial exchange occurred with or without the inhibitors at certain side-chain methyl and methylene groups: Asn-H{sup {beta}}, Asp-H{sup {beta}}, Gln-H{sup {gamma}}, Glu-H{sup {gamma}}, and Lys-H{sup {epsilon}}. The side-chain labeling pattern, in particular the mixed chiral labeling resulting from partial exchange at certain sites, should be of

Exchange effects in Relativistic Schroedinger Theory

International Nuclear Information System (INIS)

Sigg, T.; Sorg, M.

1998-01-01

The Relativistic Schroedinger Theory predicts the occurrence of exchange and overlap effects in many-particle systems. For a 2-particle system, the interaction energy of the two particles consists of two contributions: Coulomb energy and exchange energy, where the first one is revealed to be the same as in standard quantum theory. However the exchange energy is mediated by an exchange potential, contrary to the kinematical origin of the exchange term in the standard theory

Effective Exchange Rate Classifications and Growth

OpenAIRE

Justin M. Dubas; Byung-Joo Lee; Nelson C. Mark

2005-01-01

We propose an econometric procedure for obtaining de facto exchange rate regime classifications which we apply to study the relationship between exchange rate regimes and economic growth. Our classification method models the de jure regimes as outcomes of a multinomial logit choice problem conditional on the volatility of a country's effective exchange rate, a bilateral exchange rate and international reserves. An `effective' de facto exchange rate regime classification is then obtained by as...

Exchange currents in nuclear physics

International Nuclear Information System (INIS)

Truglik, Eh.

1980-01-01

Starting from Adler's low-energy theorem for the soft pion production amplitudes the predictions of the meson exchange currents theory for the nuclear physics are discussed. The results are reformulated in terms of phenomenological lagrangians. This method allows one to pass naturally to the more realistic case of hard mesons. The predictions are critically compared with the existing experimental data. The main processes in which vector isovector exchange currents, vector isoscalar exchange currents and axial exchange currents take place are pointed out