Conversation Analysis of Boke-tsukkomi Exchange in Japanese Comedy

Directory of Open Access Journals (Sweden)

Hideo Tsutsumi

2011-12-01

Full Text Available This article analyses and discusses what Japanese comical exchange called boke-tsukkomi is like and how it draws laughter. Conversation analysis and incongruity resolution are used as methods for the examination of the boke-tsukkomi examples. This paper will lend itself to further research on the dyadic exchange in the cross cultural context.

Method of burning ion-exchange resin contaminated with radioactivity

International Nuclear Information System (INIS)

Suzuki, Shigenori.

1986-01-01

Purpose: To process spent ion exchange resins to reduce their volume, without increasing the load on a off-gas system and in a stable state and at the same time not leaving any uncombusted portions. Method: The water slurries of the ion exchange resins contaminated with radioactive materials is dehydrated or dry combusted to reduce the water content. A binder is then added to solidify the ion exchange resin. The solidified ion exchange resins are then combusted in a furnace. This prevents the ion exchange resin from being dispersed by air and combustion gases. Furthermore, the solidified ion exchange resins in the form of small pellets burn from the surface inwards. Moreover the binder is carbonized by the combustion heat and promotes combustion to convert the ion exchange resins into a solid mass, making sure that no uncombusted portion is left. (Takahashi, M.)

Methods of designing and manufacturing a heat exchanger for the ...

African Journals Online (AJOL)

The article describes the method of calculation, design and manufacture of the the plate heat exchanger for the gas turbine plants with heat recovery. We represented the method of threedimensional calculation, which allowed conducting a virtual experiment and clarifying the design of the heat exchanger for the given ...

A method for generating high resolution satellite image time series

Science.gov (United States)

Guo, Tao

2014-10-01

There is an increasing demand for satellite remote sensing data with both high spatial and temporal resolution in many applications. But it still is a challenge to simultaneously improve spatial resolution and temporal frequency due to the technical limits of current satellite observation systems. To this end, much R&D efforts have been ongoing for years and lead to some successes roughly in two aspects, one includes super resolution, pan-sharpen etc. methods which can effectively enhance the spatial resolution and generate good visual effects, but hardly preserve spectral signatures and result in inadequate analytical value, on the other hand, time interpolation is a straight forward method to increase temporal frequency, however it increase little informative contents in fact. In this paper we presented a novel method to simulate high resolution time series data by combing low resolution time series data and a very small number of high resolution data only. Our method starts with a pair of high and low resolution data set, and then a spatial registration is done by introducing LDA model to map high and low resolution pixels correspondingly. Afterwards, temporal change information is captured through a comparison of low resolution time series data, and then projected onto the high resolution data plane and assigned to each high resolution pixel according to the predefined temporal change patterns of each type of ground objects. Finally the simulated high resolution data is generated. A preliminary experiment shows that our method can simulate a high resolution data with a reasonable accuracy. The contribution of our method is to enable timely monitoring of temporal changes through analysis of time sequence of low resolution images only, and usage of costly high resolution data can be reduces as much as possible, and it presents a highly effective way to build up an economically operational monitoring solution for agriculture, forest, land use investigation

New device based on the super spatial resolution (SSR) method

International Nuclear Information System (INIS)

Soluri, A.; Atzeni, G.; Ucci, A.; Bellone, T.; Cusanno, F.; Rodilossi, G.; Massari, R.

2013-01-01

Recently it have been described that innovative methods, namely Super Spatial Resolution (SSR), can be used to improve the scintigraphic imaging. The aim of SSR techniques is the enhancement of the resolution of an imaging system, using information from several images. In this paper we describe a new experimental apparatus that could be used for molecular imaging and small animal imaging. In fact we present a new device, completely automated, that uses the SSR method and provides images with better spatial resolution in comparison to the original resolution. Preliminary small animal imaging studies confirm the feasibility of a very high resolution system in scintigraphic imaging and the possibility to have gamma cameras using the SSR method, to perform the applications on functional imaging. -- Highlights: • Super spatial resolution brings a high resolution image from scintigraphic images. • Resolution improvement depends on the signal to noise ratio of the original images. • The SSR shows significant improvement on spatial resolution in scintigraphic images. • The SSR method is potentially utilizable for all scintigraphic devices

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)

Development and Application of Ligand-Exchange Reaction Method ...

African Journals Online (AJOL)

Purpose: This paper presents an improved kinetic-spectrophotometric procedure for determining clonazepam (CZP) in pharmaceutical formulations and human serum. Methods: The method is based on ligand-exchange reaction. The reaction was followed spectrophotometrically by measuring the rate of change of ...

Hydrogen Exchange Mass Spectrometry

Science.gov (United States)

Mayne, Leland

2018-01-01

Hydrogen exchange (HX) methods can reveal much about the structure, energetics, and dynamics of proteins. The addition of mass spectrometry (MS) to an earlier fragmentation-separation HX analysis now extends HX studies to larger proteins at high structural resolution and can provide information not available before. This chapter discusses experimental aspects of HX labeling, especially with respect to the use of MS and the analysis of MS data. PMID:26791986

Development of Preparation Methods for Alkaline Anion Exchange Membranes by Radiation

International Nuclear Information System (INIS)

Shin, Jun Hwa; Nho, Young Chang; Sohn, Joon Yong

2010-01-01

The objective of this project is to contribute to the environmentally friendly fuel cell system by developing a radiation grafting method for the preparation of anion exchange membranes for alkaline fuel cell and finally to the radiation technology industry. In this project, the preparation methods for the VBC-grafted fluoropolymer films using radiation have been developed and anion exchange membranes have been prepared via the reaction between the VBC-grafted fluoropolymer films and amines. The prepared anion exchange membranes were characterized and the performance of the membranes were evaluated

Multi-example feature-constrained back-projection method for image super-resolution

Institute of Scientific and Technical Information of China (English)

Junlei Zhang; Dianguang Gai; Xin Zhang; Xuemei Li

2017-01-01

Example-based super-resolution algorithms,which predict unknown high-resolution image information using a relationship model learnt from known high- and low-resolution image pairs, have attracted considerable interest in the field of image processing. In this paper, we propose a multi-example feature-constrained back-projection method for image super-resolution. Firstly, we take advantage of a feature-constrained polynomial interpolation method to enlarge the low-resolution image. Next, we consider low-frequency images of different resolutions to provide an example pair. Then, we use adaptive k NN search to find similar patches in the low-resolution image for every image patch in the high-resolution low-frequency image, leading to a regression model between similar patches to be learnt. The learnt model is applied to the low-resolution high-frequency image to produce high-resolution high-frequency information. An iterative back-projection algorithm is used as the final step to determine the final high-resolution image.Experimental results demonstrate that our method improves the visual quality of the high-resolution image.

A practical method for measuring the ion exchange capacity decrease of hydroxide exchange membranes during intrinsic degradation

Science.gov (United States)

Kreuer, Klaus-Dieter; Jannasch, Patric

2018-01-01

In this work we present a practical thermogravimetric method for quantifying the IEC (ion exchange capacity) decrease of hydroxide exchange membranes (HEMs) during intrinsic degradation mainly occurring through nucleophilic attack of the anion exchanging group by hydroxide ions. The method involves measuring weight changes under controlled temperature and relative humidity. These conditions are close to these in a fuel cell, i.e. the measured degradation rate includes all effects originating from the polymeric structure, the consumption of hydroxide ions and the release of water. In particular, this approach involves no added solvents or base, thereby avoiding inaccuracies that may arise in other methods due to the presence of solvents (other than water) or co-ions (such as Na+ or K+). We demonstrate the method by characterizing the decomposition of membranes consisting of poly(2,6-dimethyl-1,4-phenylene oxide) functionalized with trimethyl-pentyl-ammonium side chains. The decomposition rate is found to depend on temperature, relative humidity RH (controlling the hydration number λ) and the total water content (controlled by the actual IEC and RH).

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.

Gas-phase fragmentation of peptides to increase the spatial resolution of the Hydrogen Exchange Mass Spectrometry experiment

DEFF Research Database (Denmark)

Jensen, Pernille Foged; Rand, Kasper Dyrberg

2016-01-01

are produced after precursor ion selection and thus do not add complexity to the LC-MS analysis. The key to obtaining optimal spatial resolution in a hydrogen exchange mass spectrometry (HX-MS) experiment is the fragmentation efficiency. This chapter discusses common fragmentation techniques like collision....../D scrambling, thus making them suitable for HX applications. By combining the classic bottom-up HX-MS workflow with gas-phase fragmentation by ETD, detailed information on protein HX can be obtained....

Resolution enhancement of holographic printer using a hogel overlapping method.

Science.gov (United States)

Hong, Keehoon; Park, Soon-gi; Yeom, Jiwoon; Kim, Jonghyun; Chen, Ni; Pyun, Kyungsuk; Choi, Chilsung; Kim, Sunil; An, Jungkwuen; Lee, Hong-Seok; Chung, U-in; Lee, Byoungho

2013-06-17

We propose a hogel overlapping method for the holographic printer to enhance the lateral resolution of holographic stereograms. The hogel size is directly related to the lateral resolution of the holographic stereogram. Our analysis by computer simulation shows that there is a limit to decreasing the hogel size while printing holographic stereograms. Instead of reducing the size of hogel, the lateral resolution of holographic stereograms can be enhanced by printing overlapped hogels, which makes it possible to take advantage of multiplexing property of the volume hologram. We built a holographic printer, and recorded two holographic stereograms using the conventional and proposed overlapping methods. The images and movies of the holographic stereograms experimentally captured were compared between the conventional and proposed methods. The experimental results confirm that the proposed hogel overlapping method improves the lateral resolution of holographic stereograms compared to the conventional holographic printing method.

Resolution and optimization methods for tour planning problems

International Nuclear Information System (INIS)

Vasserot, Jean-Pierre

1976-12-01

The aim of this study is to describe computerized methods for the resolution of the computer supported tour planning problem. After a presentation of this problem in operational research, the different existing methods of resolution are reviewed with the different approaches which have led to their elaboration. Different critics and comparisons are made on these methods and some improvements and new procedures are proposed, some of them allowing to solve more general problems. Finally, the structure of such a program, made at the CII to solve this kind of problem under multiple constraints is analysed [fr

Lead titanate nanotubes synthesized via ion-exchange method: Characteristics and formation mechanism

International Nuclear Information System (INIS)

Song Liang; Cao Lixin; Li Jingyu; Liu Wei; Zhang Fen; Zhu Lin; Su Ge

2011-01-01

Highlights: → Lead titanate nanotubes PbTi 3 O 7 were firstly synthesized by ion-exchange method. → Sodium titanate nanotubes have ion exchangeability. → Lead titanate nanotubes show a distinct red shift on absorption edge. - Abstract: A two-step method is presented for the synthesis of one dimensional lead titanate (PbTi 3 O 7 ) nanotubes. Firstly, titanate nanotubes were prepared by an alkaline hydrothermal process with TiO 2 nanopowder as precursor, and then lead titanate nanotubes were formed through an ion-exchange reaction. We found that sodium titanate nanotubes have ion exchangeability with lead ions, while protonated titanate nanotubes have not. For the first time, we distinguished the difference between sodium titanate nanotubes and protonated titanate nanotubes in the ion-exchange process, which reveals a layer space effect of nanotubes in the ion-exchange reaction. In comparison with sodium titanate, the synthesized lead titanate nanotubes show a narrowed bandgap.

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.

THE EFFECT OF EXCHANGE RATE ON THE CONSTRUCTION PROJECTS AND PROTECTION METHODS

Directory of Open Access Journals (Sweden)

Handan AKSUYEK,

2017-02-01

Full Text Available As with all sectors, recent extreme changes occurred in the exchange rates have substantially affected the construction operations. While the rise in foreign exchange rates leads to harmful effects in the negative direction at the operations having foreign exchange – based debt or it provides also advantageous effect in the positive direction at the construction companies having foreign exchange – indexed investments. In this context, this sudden change in foreign exchange rates which cannot be predicted beforehand and emerges as a result of speculative events. As with all operations carrying out foreign exchange – based tasks, these fluctuations in the foreign exchange rate head first among the factors which affect the achievement or failure of the cost or profit targets previously determined by the construction companies as well. Therefore, the companies whose costs and profits consist of different units of currency in their construction agreements should apply to the hedging methods in order to be protected against the exchange rate. As for the main tools of protection method are the derivative products such as forward, futures, swap and optional contracts. In this study, the effect of exchange rate fluctuations on the completion costs of construction projects is scrutinized. Moreover, the tools which may be employed by the construction companies in order to get rid of exchange rate which adversely influence the building companies in both directions have been comparatively evaluated.

Detector Motion Method to Increase Spatial Resolution in Photon-Counting Detectors

Energy Technology Data Exchange (ETDEWEB)

Lee, Daehee; Park, Kyeongjin; Lim, Kyung Taek; Cho, Gyuseong [Korea Advanced Institute of Science and Technology, Daejon (Korea, Republic of)

2017-03-15

Medical imaging requires high spatial resolution of an image to identify fine lesions. Photoncounting detectors in medical imaging have recently been rapidly replacing energy-integrating detectors due to the former's high spatial resolution, high efficiency and low noise. Spatial resolution in a photon counting image is determined by the pixel size. Therefore, the smaller the pixel size, the higher the spatial resolution that can be obtained in an image. However, detector redesigning is required to reduce pixel size, and an expensive fine process is required to integrate a signal processing unit with reduced pixel size. Furthermore, as the pixel size decreases, charge sharing severely deteriorates spatial resolution. To increase spatial resolution, we propose a detector motion method using a large pixel detector that is less affected by charge sharing. To verify the proposed method, we utilized a UNO-XRI photon-counting detector (1-mm CdTe, Timepix chip) at the maximum X-ray tube voltage of 80 kVp. A similar spatial resolution of a 55-μm-pixel image was achieved by application of the proposed method to a 110-μm-pixel detector with a higher signal-to-noise ratio. The proposed method could be a way to increase spatial resolution without a pixel redesign when pixels severely suffer from charge sharing as pixel size is reduced.

Development of fast charge exchange recombination spectroscopy by using interference filter method in JT-60U

International Nuclear Information System (INIS)

Kobayashi, Shinji; Sakasai, Akira; Koide, Yoshihiko; Sakamoto, Yoshiteru; Kamada, Yutaka; Hatae, Takaki; Oyama, Naoyuki; Miura, Yukitoshi

2003-01-01

Recent developments and results of fast charge exchange recombination spectroscopy (CXRS) using interference filter method are reported. In order to measure the rapid change of the ion temperature and rotation velocity under collapse or transition phenomena with high-time resolution, two types of interference filter systems were applied to the CXRS diagnostics on the JT-60U Tokamak. One can determine the Doppler broadening and Doppler shift of the CXR emission using three interference filters having slightly different center wavelengths. A rapid estimation method of the temperature ad rotation velocity without non-linear least square fitting is presented. The modification of the three-filters system enables us to improve the minimum time resolution up to 0.8 ms, which is better than that of 16.7 ms for the conventional CXRS system using the CCD detector in JT-60U. The other system having seven wavelength channels is newly fabricated to crosscheck the results obtained by the three-filters assembly, that is, to verify that the CXR emission forms a Gaussian profile under collapse phenomena. In a H-mode discharge having giant edge localized modes, the results obtained by the two systems are compared. The applicability of the three-filters system to the measurement of rapid changes in temperature and rotation velocity is demonstrated. (author)

Study of thermal accumulators-exchangers containing low temperature (20-80c) phase transformation materials

Energy Technology Data Exchange (ETDEWEB)

Lecomte, D.

1983-06-01

After a review of the various types of heat exchanger technologies (especially the tube and plate types), an analytical and experimental study of a rotating cylinder dynamical accumulator-exchanger is presented and extended to a larger scale accumulator. The various analytical and numerical methods for the resolution of the heat equation in a diphasic medium and the problems caused by the presence of an exchanger and by the natural convection are described. Two approaches for the immersed tubular exchangers are compared and used to modelize a real storage system. A dimensioning procedure is then proposed.

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.

Exchange rates of creatine kinase metabolites: feasibility of imaging creatine by chemical exchange saturation transfer MRI.

Science.gov (United States)

Haris, Mohammad; Nanga, Ravi Prakash Reddy; Singh, Anup; Cai, Kejia; Kogan, Feliks; Hariharan, Hari; Reddy, Ravinder

2012-11-01

Creatine (Cr), phosphocreatine (PCr) and adenosine-5-triphosphate (ATP) are major metabolites of the enzyme creatine kinase (CK). The exchange rate of amine protons of CK metabolites at physiological conditions has been limited. In the current study, the exchange rate and logarithmic dissociation constant (pKa) of amine protons of CK metabolites were calculated. Further, the chemical exchange saturation transfer effect (CEST) of amine protons of CK metabolites with bulk water was explored. At physiological temperature and pH, the exchange rate of amine protons in Cr was found to be 7-8 times higher than PCr and ATP. A higher exchange rate in Cr was associated with lower pKa value, suggesting faster dissociation of its amine protons compared to PCr and ATP. CEST MR imaging of these metabolites in vitro in phantoms displayed predominant CEST contrast from Cr and negligible contribution from PCr and ATP with the saturation pulse parameters used in the current study. These results provide a new method to perform high-resolution proton imaging of Cr without contamination from PCr. Potential applications of these finding are discussed. Copyright © 2012 John Wiley & Sons, Ltd.

Composite sorbents of inorganic ion-exchangers and polyacrylonitrile binding matrix. Methods of modification of properties of inorganic ion-exchangers for application in column packed beds

International Nuclear Information System (INIS)

Sebesta, F.

1997-01-01

Methods of preparation of granules of inorganic ion exchangers as well as methods for improvement of granular strength of these materials are reviewed. The resulting ion exchangers are classified in three groups - 'intrinsic', supported and composite ion exchangers. Their properties are compared and possibilities of their technological application are evaluated. A new method of preparation of inorganic-organic composite sorbents of inorganic ion-exchangers and polyacrylonitrile binding matrix is described, advantages and disadvantages of such sorbents are discussed. Proposed fields of application include tratment of liquid radioactive and/or hazardous wastes, decontamination of natural water as well as analytical applications. (author)

A screening method for the optimal selection of plate heat exchanger configurations

Directory of Open Access Journals (Sweden)

Pinto J.M.

2002-01-01

Full Text Available An optimization method for determining the best configuration(s of gasketed plate heat exchangers is presented. The objective is to select the configuration(s with the minimum heat transfer area that still satisfies constraints on the number of channels, the pressure drop of both fluids, the channel flow velocities and the exchanger thermal effectiveness. The configuration of the exchanger is defined by six parameters, which are as follows: the number of channels, the numbers of passes on each side, the fluid locations, the feed positions and the type of flow in the channels. The resulting configuration optimization problem is formulated as the minimization of the exchanger heat transfer area and a screening procedure is proposed for its solution. In this procedure, subsets of constraints are successively applied to eliminate infeasible and nonoptimal solutions. Examples show that the optimization method is able to successfully determine a set of optimal configurations with a minimum number of exchanger evaluations. Approximately 5 % of the pressure drop and channel velocity calculations and 1 % of the thermal simulations are required for the solution.

Methods of uranium isotpic separation by chemical exchange chromatography

International Nuclear Information System (INIS)

Pena V, L.A.; Valle M, L.

1985-01-01

Chemical exchange chromatography as applied to isotope separation has undergone a constant development during the last few years. The results so far indicate that this method could eventually become commercially useful. This work presents a critical review of the experimental methods presently under study by principal research groups, and which have not get been compared. (Author)

Method of solidifying radioactive ion exchange resin

International Nuclear Information System (INIS)

Minami, Yuji; Tomita, Toshihide

1989-01-01

Spent anion exchange resin formed in nuclear power plants, etc. generally catch only a portion of anions in view of the ion exchange resins capacity and most of the anions are sent while possessing activities to radioactive waste processing systems. Then, the anion exchange resins increase the specific gravity by the capture of the anions. Accordingly, anions are caused to be captured on the anion exchange resin wastes such that the specific gravity of the anion exchange resin wastes is greater than that of the thermosetting resins to be mixed. This enables satisfactory mixing with the thermosetting resins and, in addition, enables to form integral solidification products in which anion exchange resins and cation exchange resins are not locallized separately and which are homogenous and free from cracks. (T.M.)

Modified momentum exchange method for fluid-particle interactions in the lattice Boltzmann method.

Science.gov (United States)

Hu, Yang; Li, Decai; Shu, Shi; Niu, Xiaodong

2015-03-01

In this paper, a modified momentum exchange method for fluid-particle interactions is proposed based on the finite-volume lattice Boltzmann method. The idea of the improvement is to remove the restriction that the boundary points must be set as the midpoints of the grid lines or the intersection of the grid lines with the solid boundaries. The particle surface is represented by a set of arc (area) elements, and the interior fluid is used which the geometric conservation law is naturally satisfied. The interactions between fluid and arc (area) elements of particle boundary are considered using the momentum exchange method, and the mass of the fluid particles which collide with an arc (area) element is obtained by means of numerical integration in the control volume. The fluid field is corrected with the help of the smooth kernel function. Moreover, a generalized explicit time marching scheme is introduced to resolve the motion of particle in the problems with the ratio of particle density to fluid density is close to or less than 1. Finally, some numerical case studies of particle sedimentation are carried out to validate the present method. The corresponding results have a good agreement with the previous literature, which strongly demonstrates the capability of the improved method.

Derivation of effectiveness-NTU method for heat exchangers with heat leak; TOPICAL

International Nuclear Information System (INIS)

William M. Soyars

2001-01-01

A powerful and useful method for heat exchanger analysis is the effectiveness-NTU method. The equations for this technique presented in textbooks, however, are limited to the case where all of the heat transfer occurs between the two fluid streams. In an application of interest to us, cryogenic heat exchangers, we wish to consider a heat leak term. Thus, we have derived equations for the(var e psilon)-NTU method with heat leak involved. The cases to be studied include evaporators, condensers, and counter-flow, with heat leak both in and out

A thermal design method for the performance optimization of multi-stream plate-fin heat exchangers

Energy Technology Data Exchange (ETDEWEB)

Wang, Zhe; Li, Yanzhong [Xi’an Jiaotong University, Xi’an (China); Sunden, Bengt [Lund University, Lund (Sweden); Han, Fenghui [Dalian Maritime University, Dalian (China)

2017-06-15

An optimization design method based on field synergy principle is developed for Multi-stream plate-fin heat exchangers (MPHEs) with a segmented differential model. The heat exchanger is divided into a number of sub-exchangers along the main stream, and each sub-exchanger consists of N passages along the height of the exchanger. Compared with the traditional heat exchanger design, this method allows temperature and pressure fields to be obtained via coupling calculation with consideration of variable physical properties and the axial heat loss of the heat exchanger. Finally, the heat exchanger is optimally designed using a temperature-difference uniformity optimization factor based on field synergy principle. This design model can provide an accurate temperature field and pressure field, because the stream properties are determined by the mean temperature and pressure of each local sub-exchanger. Optimum results indicate that the temperature distribution on the cross section of the heat exchanger is relatively uniform and that the temperature difference of heat transfer for each stream is always a small value. These characteristics prove the feasibility and effectiveness of this design model. In this paper, a case of five stream plate-fin heat exchangers for an ethylene plant is designed under a practical cold box operating condition with the proposed model, the structure and heat transfer of which are optimally determined. The design model and optimization method proposed in this work can provide theoretical and technical support to the optimization design of MPHEs.

Comparison of methods for measuring the ion exchange capacity of a soil. Development of a quick method

International Nuclear Information System (INIS)

Amavis, R.

1959-01-01

In the course of a study on the movement of radioactive ions in soil we had to measure the cationic exchange capacity of various soil samples, this parameter being one of the most important in the appreciation of the extent of fixation of radioactive ions in the ground. The object of this report is to describe the various methods used and to compare the results obtained. A colorimetric method, using Co(NH 3 ) 6 3+ as exchangeable ion, was developed. It gives results comparable to those obtained with conventional methods, whilst considerably reducing the time necessary for the operations. (author) [fr

A Method to Establishing Tube Plugging Criterion for Heat Exchangers with Straight Tubes

Energy Technology Data Exchange (ETDEWEB)

Kim, Hyungnam [KHNP CRI, Daejeon (Korea, Republic of)

2016-10-15

The difference of thermal expansion coefficients between the shell and tube materials causes the stress in axial direction of tube. Because of the axial stress due to thermal load, the straight tubes are used for heat exchangers operated in low temperature such as CCW (Component Cooling Water) heat exchangers and condensers. It is inevitable for the materials of the components to be degraded as the power plants become older. The degradation accompanies increasing maintenance cost as well as creating safety issues. The materials and wall thickness of heat exchanger tubes in nuclear power plants are selected to withstand system temperature, pressure, and corrosion. There are many codes and standards to be referred for calculating the minimum thickness of the heat exchanger tube in the designing stage. However, the codes and standards related to show the tube plugging criteria may not exist currently. In this paper, a method to establish the tube plugging criteria of BOP heat exchangers, which is based on the USNRC Regulatory Guide 1.121, is introduced and the tube plugging criteria for the TPCCW heat exchanger of Yonggwang NPP No. 1 and 2. A method to establish the tube plugging criteria of heat exchangers with straight tubes are introduced based on the USNRC Regulatory Guide 1.121. As an example, the tube plugging criterion for the CCW heat exchanger of a nuclear power plant is provided.

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.

Tritium-exchange method for obsidian hydration shell measurement

Energy Technology Data Exchange (ETDEWEB)

Lowe, J P; Wilson, A T; Lowe, D J; Hodder, A P.W. [Waikato Univ., Hamilton (New Zealand)

1984-12-01

A new radiochemical method for measuring the amount of water in the hydrated layer on the surface of obsidians exchanges tritiated water with the water in the layer (20 ..mu..l of 5 Ci ml/sup -1/ at 90/sup 0/C for 10 days) and then back-exchanges it (in 150 ml of water at 35/sup 0/C for approx. 200 hr.). The activity of the back-exchange water (F) is monitored by liquid scintillation counting of aliquots extracted at known time intervals (t). The activity so measured is then related to the thickness of the hydration rim. A sheet diffusion model shows that the thickness of the hydration shell (l) is inversely proportional to the slope of the F vs. tsup(1/2) plot. Comparison of l-values so obtained between obsidians, whose age (x) is inferred from archaeological occupation layers containing radiocarbon-dated wood and charcoal, suggests a relationship between l and x. Implications for New Zealand prehistory are briefly considered. The technique, which is non-destructive, appears particularly applicable to young glasses where the development of hydrated layers may be inadequate for accurate optical measurement.

Site-Specific Hydrogen Isotope Composition of Propane: Mass spectrometric methods, equilibrium temperature dependence, and kinetics of exchange

Science.gov (United States)

Xie, H.; Ponton, C.; Kitchen, N.; Lloyd, M. K.; Lawson, M.; Formolo, M. J.; Eiler, J. M.

2016-12-01

Intramolecular isotope ordering can constrain temperatures of synthesis, mechanisms of formation, and/or source substrates of organic compounds. Here we explore site-specific hydrogen isotope variations of propane. Statistical thermodynamic models predict that at equilibrium methylene hydrogen (-CH2-) in propane will be 10's of per mil higher in D/H ratio than methyl hydrogen (-CH3) at geologically relevant temperatures, and that this difference is highly temperature dependent ( 0.5-1 ‰/°C). Chemical-kinetic controls on site-specific D/H in propane could constrain the mechanisms, conditions and extents of propane synthesis or destruction. We have developed a method for measuring the difference in D/H ratio between methylene and methyl hydrogen in propane by gas source mass spectrometry. The data were measured using the Thermo Fisher Double Focusing Sector high resolution mass spectrometer (DFS), and involve comparison of the D/H ratios of molecular ion (C3H8+) and the ethyl fragmental ion (C2H5+). We demonstrate the accuracy and precision of this method through analysis of D-labeled and independently analyzed propanes. In the exchange experiments, propane was heated (100-200 oC) either alone or in the presence of D-enriched water (δD=1,1419 ‰ SMOW), with or without one of several potentially catalytic substrates for hours to weeks. Propane was found to exchange hydrogen with water vigorously at 200 °C in the presence of metal catalysts. In the presence of Ni catalyst, methylene hydrogen exchanges 2.5 times faster than methyl hydrogen. Hydrogen exchange in the presence of Pd catalyst is more effective and can equilibrate hydrogen isotope distribution on propane on the order of 7 days. Isotopic exchange in the presence of natural materials have also been tested, but is only measurable in the methylene group at 200 °C. High catalytic activity of Pd permits attainment of a bracketed, time-invariant equilibrium state that we use to calibrate the site

Resolution enhancement of tri-stereo remote sensing images by super resolution methods

Science.gov (United States)

Tuna, Caglayan; Akoguz, Alper; Unal, Gozde; Sertel, Elif

2016-10-01

Super resolution (SR) refers to generation of a High Resolution (HR) image from a decimated, blurred, low-resolution (LR) image set, which can be either a single frame or multi-frame that contains a collection of several images acquired from slightly different views of the same observation area. In this study, we propose a novel application of tri-stereo Remote Sensing (RS) satellite images to the super resolution problem. Since the tri-stereo RS images of the same observation area are acquired from three different viewing angles along the flight path of the satellite, these RS images are properly suited to a SR application. We first estimate registration between the chosen reference LR image and other LR images to calculate the sub pixel shifts among the LR images. Then, the warping, blurring and down sampling matrix operators are created as sparse matrices to avoid high memory and computational requirements, which would otherwise make the RS-SR solution impractical. Finally, the overall system matrix, which is constructed based on the obtained operator matrices is used to obtain the estimate HR image in one step in each iteration of the SR algorithm. Both the Laplacian and total variation regularizers are incorporated separately into our algorithm and the results are presented to demonstrate an improved quantitative performance against the standard interpolation method as well as improved qualitative results due expert evaluations.

Two methods to estimate the position resolution for straw chambers with strip readout

International Nuclear Information System (INIS)

Golutvin, I.A.; Movchan, S.A.; Peshekhonov, V.D.; Preda, T.

1992-01-01

The centroid and charge-ratio methods are presented to estimate the position resolution of the straw chambers with strip readout. For the straw chambers of 10 mm in diameter, the highest position resolution was obtained for a strip pitch of 5 mm. With the centroid method and perpendicular X-ray beam, the position resolution was ≅120 μm, for the signal-to-noise ratio of 60-65. The charge-ratio method has demonstrated ≅10% better position resolution at the edges of the strip. 6 refs.; 5 figs

48 CFR 6302.30 - Alternative dispute resolution methods (Rule 30).

Science.gov (United States)

2010-10-01

... TRANSPORTATION BOARD OF CONTRACT APPEALS RULES OF PROCEDURE 6302.30 Alternative dispute resolution methods (Rule... Alternative Dispute Resolution (ADR): Settlement Judges and Mini-Trials. These procedures are designed to... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Alternative dispute...

The ion exchange and its connection the industry II.- Calculation methods for installations; El cambio de ion y su relacion con la industria II.- Metodos de calculo de instalaciones

Energy Technology Data Exchange (ETDEWEB)

Uriarte Hueda, A; Lopez Perez, B; Gutierrez Jodra, L

1960-07-01

An exposure is made of calculation methods for ion exchange installations based on kinetic considerations and similarity with other unitary operations. Factors to be experimentally obtained as well as difficulties which may occur in its determination are also given. Calculation procedures most commonly used in industry are enclosed and explained with numerical resolution of a problem of water demineralization. (Author) 22 refs.

An ROI multi-resolution compression method for 3D-HEVC

Science.gov (United States)

Ti, Chunli; Guan, Yudong; Xu, Guodong; Teng, Yidan; Miao, Xinyuan

2017-09-01

3D High Efficiency Video Coding (3D-HEVC) provides a significant potential on increasing the compression ratio of multi-view RGB-D videos. However, the bit rate still rises dramatically with the improvement of the video resolution, which will bring challenges to the transmission network, especially the mobile network. This paper propose an ROI multi-resolution compression method for 3D-HEVC to better preserve the information in ROI on condition of limited bandwidth. This is realized primarily through ROI extraction and compression multi-resolution preprocessed video as alternative data according to the network conditions. At first, the semantic contours are detected by the modified structured forests to restrain the color textures inside objects. The ROI is then determined utilizing the contour neighborhood along with the face region and foreground area of the scene. Secondly, the RGB-D videos are divided into slices and compressed via 3D-HEVC under different resolutions for selection by the audiences and applications. Afterwards, the reconstructed low-resolution videos from 3D-HEVC encoder are directly up-sampled via Laplace transformation and used to replace the non-ROI areas of the high-resolution videos. Finally, the ROI multi-resolution compressed slices are obtained by compressing the ROI preprocessed videos with 3D-HEVC. The temporal and special details of non-ROI are reduced in the low-resolution videos, so the ROI will be better preserved by the encoder automatically. Experiments indicate that the proposed method can keep the key high-frequency information with subjective significance while the bit rate is reduced.

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.

Resolution Enhancement Method Used for Force Sensing Resistor Array

Directory of Open Access Journals (Sweden)

Karen Flores De Jesus

2015-01-01

Full Text Available Tactile sensors are one of the major devices that enable robotic systems to interact with the surrounding environment. This research aims to propose a mathematical model to describe the behavior of a tactile sensor based on experimental and statistical analyses and moreover to develop a versatile algorithm that can be applied to different tactile sensor arrays to enhance the limited resolution. With the proposed algorithm, the resolution can be increased up to twenty times if multiple measurements are available. To verify if the proposed algorithm can be used for tactile sensor arrays that are used in robotic system, a 16×10 force sensing array (FSR is adopted. The acquired two-dimensional measurements were processed by a resolution enhancement method (REM to enhance the resolution, which can be used to improve the resolution for single image or multiple measurements. As a result, the resolution of the sensor is increased and it can be used as synthetic skin to identify accurate shapes of objects and applied forces.

Letter: Observation of the 16O/18O exchange during electrospray ionization.

Science.gov (United States)

Kostyukevich, Yury; Kononikhin, Alexey; Popov, Igor; Nikolaev, Eugene

2015-01-01

Isotopic exchange approach coupled to high-resolution mass spectrometry has become the power analytical approach for a wide range of analytical and bioanalyticall applications. Considerable efforts have been dedicated to developing fast exchange techniques directly in the ionization source. But all such methods are limited to the hydrogen/deuterium exchange approaches. In this paper we demonstrate that certain types of oxygen atoms can also be exchanged for (18)O on the time scale of the ionization process. Using HIO(3) and NaIO(4) and by infusing the heavy water H(2)(18)O in the ESI source we have demonstrated that it is possible to obtain a high level of oxygen exchange. It was observed that the rate of this exchange depends to a large extent on the temperature of the desolvating capillary of the mass spectrometer. Several other species, such as peptides, oligonucleotides and low weight organic molecules, were subjected to in-ESI (16)O/(18)O exchange but the exchange was not observed.

Removal of plutonium from nitric acid-oxalic acid solutions using anion exchange method

International Nuclear Information System (INIS)

Kasar, U.M.; Pawar, S.M.; Joshi, A.R.

1999-01-01

An anion exchange method using Amberlyst A-26 (MP) resin was developed for removal of Pu from nitric acid-oxalic acid solutions without destroying oxalate. The method consists of sorption of Pu(IV) on Amberlyst A-26, a macroporous anion exchange resin, from nitric acid-oxalic acid medium in the presence of Al(NO 3 ) 3 . Pu(IV) breakthrough capacity of Amberlyst A-26 using synthetic feed solution was determined. (author)

A Simple Halide-to-Anion Exchange Method for Heteroaromatic Salts and Ionic Liquids

Directory of Open Access Journals (Sweden)

Neus Mesquida

2012-04-01

Full Text Available A broad and simple method permitted halide ions in quaternary heteroaromatic and ammonium salts to be exchanged for a variety of anions using an anion exchange resin (A− form in non-aqueous media. The anion loading of the AER (OH− form was examined using two different anion sources, acids or ammonium salts, and changing the polarity of the solvents. The AER (A− form method in organic solvents was then applied to several quaternary heteroaromatic salts and ILs, and the anion exchange proceeded in excellent to quantitative yields, concomitantly removing halide impurities. Relying on the hydrophobicity of the targeted ion pair for the counteranion swap, organic solvents with variable polarity were used, such as CH3OH, CH3CN and the dipolar nonhydroxylic solvent mixture CH3CN:CH2Cl2 (3:7 and the anion exchange was equally successful with both lipophilic cations and anions.

A Momentum-Exchange/Fictitious Domain-Lattice Boltzmann Method for Solving Particle Suspensions

Energy Technology Data Exchange (ETDEWEB)

Jeon, Seok Yun; Yoon, Joon Yong [Hanyang Univ., Seoul (Korea, Republic of); Kim, Chul Kyu [Korea Institute of Civil Engineering and Building Technology, Goyang (Korea, Republic of); Shin, Myung Seob [Korea Intellectual Property Office(KIPO), Daejeon (Korea, Republic of)

2016-06-15

This study presents a Lattice Boltzmann Method (LBM) coupled with a momentum-exchange approach/fictitious domain (MEA/FD) method for the simulation of particle suspensions. The method combines the advantages of the LB and the FD methods by using two unrelated meshes, namely, a Eulerian mesh for the flow domain and a Lagrangian mesh for the solid domain. The rigid body conditions are enforced by the momentum-exchange scheme in which the desired value of velocity is imposed directly in the particle inner domain by introducing a pseudo body force to satisfy the constraint of rigid body motion, which is the key idea of a fictitious domain (FD) method. The LB-MEA/FD method has been validated by simulating two different cases, and the results have been compared with those through other methods. The numerical evidence illustrated the capability and robustness of the present method for simulating particle suspensions.

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)

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.

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.

Pyrosequencing™ : A one-step method for high resolution HLA typing

Directory of Open Access Journals (Sweden)

Marincola Francesco M

2003-11-01

Full Text Available Abstract While the use of high-resolution molecular typing in routine matching of human leukocyte antigens (HLA is expected to improve unrelated donor selection and transplant outcome, the genetic complexity of HLA still makes the current methodology limited and laborious. Pyrosequencing™ is a gel-free, sequencing-by-synthesis method. In a Pyrosequencing reaction, nucleotide incorporation proceeds sequentially along each DNA template at a given nucleotide dispensation order (NDO that is programmed into a pyrosequencer. Here we describe the design of a NDO that generates a pyrogram unique for any given allele or combination of alleles. We present examples of unique pyrograms generated from each of two heterozygous HLA templates, which would otherwise remain cis/trans ambiguous using standard sequencing based typing (SBT method. In addition, we display representative data that demonstrate long read and linear signal generation. These features are prerequisite of high-resolution typing and automated data analysis. In conclusion Pyrosequencing is a one-step method for high resolution DNA typing.

Highly dispersive ion exchangers in the analytical chemistry of uranium, particularly regarding separation methods

International Nuclear Information System (INIS)

Schoening, R.

1975-01-01

The reaction of water-insoluble polyvinyl pyrrolidon with uranium VI was investigated and a determination method for uranium was worked out in which the polyvinyl pyrrolidon was used as specific exchanger. Good separations of uranium from numerous transition metal ions were achieved here. The application of this exchanger for a fast and simple elution and determination method was of particular importance. A possible sorption mechanism was suggested based on the capacity curve of uranium with polyvinyl pyrrolidon and nitrogen and chloride content at maximum load. The sorption occurs by coordination of the carbonyl oxygen of single pyrrolidon rings with the protons of the complex acides and uranium. This assumption is supported by IR investigations. The sorbability of other inorganic acids was also investigated and possible structures were formulated for the sorption mechanism. In addition to this, ion exchangers were prepared based on cellulose by converting cellulose powder with aziridine and tris-1-aziridinyl-phosphine oxide. A polyethylene imine cellulose of high capacity was obtained in the conversion of cellulose powder with aziridine. This exchanger absorbs cobalt III very strongly. The exchanger loaded with cobalt III was used to separate the uranium as cyanato complex. The exchanger obtained in converting chlorated cellulose with tris-1-aziridinyl phosphine oxide also absorbs uranium VI very strongly. Thus a separation method of high specifity and selectivity was developed. (orig.) [de

A relaxation-projection method for compressible flows. Part II: Artificial heat exchanges for multiphase shocks

International Nuclear Information System (INIS)

Petitpas, Fabien; Franquet, Erwin; Saurel, Richard; Le Metayer, Olivier

2007-01-01

The relaxation-projection method developed in Saurel et al. [R. Saurel, E. Franquet, E. Daniel, O. Le Metayer, A relaxation-projection method for compressible flows. Part I: The numerical equation of state for the Euler equations, J. Comput. Phys. (2007) 822-845] is extended to the non-conservative hyperbolic multiphase flow model of Kapila et al. [A.K. Kapila, Menikoff, J.B. Bdzil, S.F. Son, D.S. Stewart, Two-phase modeling of deflagration to detonation transition in granular materials: reduced equations, Physics of Fluids 13(10) (2001) 3002-3024]. This model has the ability to treat multi-temperatures mixtures evolving with a single pressure and velocity and is particularly interesting for the computation of interface problems with compressible materials as well as wave propagation in heterogeneous mixtures. The non-conservative character of this model poses however computational challenges in the presence of shocks. The first issue is related to the Riemann problem resolution that necessitates shock jump conditions. Thanks to the Rankine-Hugoniot relations proposed and validated in Saurel et al. [R. Saurel, O. Le Metayer, J. Massoni, S. Gavrilyuk, Shock jump conditions for multiphase mixtures with stiff mechanical relaxation, Shock Waves 16 (3) (2007) 209-232] exact and approximate 2-shocks Riemann solvers are derived. However, the Riemann solver is only a part of a numerical scheme and non-conservative variables pose extra difficulties for the projection or cell average of the solution. It is shown that conventional Godunov schemes are unable to converge to the exact solution for strong multiphase shocks. This is due to the incorrect partition of the energies or entropies in the cell averaged mixture. To circumvent this difficulty a specific Lagrangian scheme is developed. The correct partition of the energies is achieved by using an artificial heat exchange in the shock layer. With the help of an asymptotic analysis this heat exchange takes a similar form as

A relaxation-projection method for compressible flows. Part II: Artificial heat exchanges for multiphase shocks

Science.gov (United States)

Petitpas, Fabien; Franquet, Erwin; Saurel, Richard; Le Metayer, Olivier

2007-08-01

The relaxation-projection method developed in Saurel et al. [R. Saurel, E. Franquet, E. Daniel, O. Le Metayer, A relaxation-projection method for compressible flows. Part I: The numerical equation of state for the Euler equations, J. Comput. Phys. (2007) 822-845] is extended to the non-conservative hyperbolic multiphase flow model of Kapila et al. [A.K. Kapila, Menikoff, J.B. Bdzil, S.F. Son, D.S. Stewart, Two-phase modeling of deflagration to detonation transition in granular materials: reduced equations, Physics of Fluids 13(10) (2001) 3002-3024]. This model has the ability to treat multi-temperatures mixtures evolving with a single pressure and velocity and is particularly interesting for the computation of interface problems with compressible materials as well as wave propagation in heterogeneous mixtures. The non-conservative character of this model poses however computational challenges in the presence of shocks. The first issue is related to the Riemann problem resolution that necessitates shock jump conditions. Thanks to the Rankine-Hugoniot relations proposed and validated in Saurel et al. [R. Saurel, O. Le Metayer, J. Massoni, S. Gavrilyuk, Shock jump conditions for multiphase mixtures with stiff mechanical relaxation, Shock Waves 16 (3) (2007) 209-232] exact and approximate 2-shocks Riemann solvers are derived. However, the Riemann solver is only a part of a numerical scheme and non-conservative variables pose extra difficulties for the projection or cell average of the solution. It is shown that conventional Godunov schemes are unable to converge to the exact solution for strong multiphase shocks. This is due to the incorrect partition of the energies or entropies in the cell averaged mixture. To circumvent this difficulty a specific Lagrangian scheme is developed. The correct partition of the energies is achieved by using an artificial heat exchange in the shock layer. With the help of an asymptotic analysis this heat exchange takes a similar form as

Fourier Deconvolution Methods for Resolution Enhancement in Continuous-Wave EPR Spectroscopy.

Science.gov (United States)

Reed, George H; Poyner, Russell R

2015-01-01

An overview of resolution enhancement of conventional, field-swept, continuous-wave electron paramagnetic resonance spectra using Fourier transform-based deconvolution methods is presented. Basic steps that are involved in resolution enhancement of calculated spectra using an implementation based on complex discrete Fourier transform algorithms are illustrated. Advantages and limitations of the method are discussed. An application to an experimentally obtained spectrum is provided to illustrate the power of the method for resolving overlapped transitions. © 2015 Elsevier Inc. All rights reserved.

Low resolution spectroscopic investigation of Am stars using Automated method

Science.gov (United States)

Sharma, Kaushal; Joshi, Santosh; Singh, Harinder P.

2018-04-01

The automated method of full spectrum fitting gives reliable estimates of stellar atmospheric parameters (Teff, log g and [Fe/H]) for late A, F, G, and early K type stars. Recently, the technique was further improved in the cooler regime and the validity range was extended up to a spectral type of M6 - M7 (Teff˜ 2900 K). The present study aims to explore the application of this method on the low-resolution spectra of Am stars, a class of chemically peculiar stars, to examine its robustness for these objects. We use ULySS with the Medium-resolution INT Library of Empirical Spectra (MILES) V2 spectral interpolator for parameter determination. The determined Teff and log g values are found to be in good agreement with those obtained from high-resolution spectroscopy.

Mercury Exchange at the Air-Water-Soil Interface: An Overview of Methods

Directory of Open Access Journals (Sweden)

Fengman Fang

2002-01-01

Full Text Available An attempt is made to assess the present knowledge about the methods of determining mercury (Hg exchange at the air-water-soil interface during the past 20 years. Methods determining processes of wet and dry removal/deposition of atmospheric Hg to aquatic and terrestrial ecosystems, as well as methods determining Hg emission fluxes to the atmosphere from natural surfaces (soil and water are discussed. On the basis of the impressive advances that have been made in the areas relating to Hg exchange among air-soil-water interfaces, we analyzed existing problems and shortcomings in our current knowledge. In addition, some important fields worth further research are discussed and proposed.

Method for the positioning of pipes in a heat exchanger

International Nuclear Information System (INIS)

1983-01-01

The invention relates to a method for positioning pipes in a heat exchanger. The grating that supports the pipes of the heat exchanger may be equipped with projections in the passages that also support the pipes. Such projections may, however, obstruct the positioning of the pipes in the grating. The purpose of the invention is to bypass this problem by applying receding projections that move outward when a wedge is put in the grating and thereupon turned round in such a way that the pipes can freely be positioned. Thereupon, the wedge is turned back and the projections will resume their positions. (Auth.)

Methods for tube attachment in a heat exchange equipment

International Nuclear Information System (INIS)

Shilin, O.V.; Vasil'ev, V.B.

1984-01-01

Two main ways of attaching tubes to tube panels in heat exchange equipment are analyzed: expanding and pulse method (by explosion, for instance). Labour-consumption and cost price for the fastening of brass, perlitic and corrosion-resistant tubes for both of the methods are presented. The extent of fitting out with equipment for tube fixing and ways of testing the joints for attachment are evaluated. Measures for improving the joint quality and introduction of the advanced technology are suggested

A Three-Dimensional Target Depth-Resolution Method with a Single-Vector Sensor.

Science.gov (United States)

Zhao, Anbang; Bi, Xuejie; Hui, Juan; Zeng, Caigao; Ma, Lin

2018-04-12

This paper mainly studies and verifies the target number category-resolution method in multi-target cases and the target depth-resolution method of aerial targets. Firstly, target depth resolution is performed by using the sign distribution of the reactive component of the vertical complex acoustic intensity; the target category and the number resolution in multi-target cases is realized with a combination of the bearing-time recording information; and the corresponding simulation verification is carried out. The algorithm proposed in this paper can distinguish between the single-target multi-line spectrum case and the multi-target multi-line spectrum case. This paper presents an improved azimuth-estimation method for multi-target cases, which makes the estimation results more accurate. Using the Monte Carlo simulation, the feasibility of the proposed target number and category-resolution algorithm in multi-target cases is verified. In addition, by studying the field characteristics of the aerial and surface targets, the simulation results verify that there is only amplitude difference between the aerial target field and the surface target field under the same environmental parameters, and an aerial target can be treated as a special case of a surface target; the aerial target category resolution can then be realized based on the sign distribution of the reactive component of the vertical acoustic intensity so as to realize three-dimensional target depth resolution. By processing data from a sea experiment, the feasibility of the proposed aerial target three-dimensional depth-resolution algorithm is verified.

Charge exchange measurements on ISX-A

International Nuclear Information System (INIS)

Neilson, G.H.

1979-04-01

Apparatus and techniques for charge exchange neutral analysis on the ISX-A (Impurity Study Experiment) tokamak are described. A new neutral analyzer incorporating mass-energy resolution was constructed and calibrated for use on ISX. Data interpretation methods which account for profile effects and neutral attenuation have also been developed and were applied to data from the mass-energy analyzer. Examples of data from ISX-A are presented to illustrate both the use of this new instrument and the applicability of the described interpretation techniques

Sensing Noncollinear Magnetism at the Atomic Scale Combining Magnetic Exchange and Spin-Polarized Imaging.

Science.gov (United States)

Hauptmann, Nadine; Gerritsen, Jan W; Wegner, Daniel; Khajetoorians, Alexander A

2017-09-13

Storing and accessing information in atomic-scale magnets requires magnetic imaging techniques with single-atom resolution. Here, we show simultaneous detection of the spin-polarization and exchange force with or without the flow of current with a new method, which combines scanning tunneling microscopy and noncontact atomic force microscopy. To demonstrate the application of this new method, we characterize the prototypical nanoskyrmion lattice formed on a monolayer of Fe/Ir(111). We resolve the square magnetic lattice by employing magnetic exchange force microscopy, demonstrating its applicability to noncollinear magnetic structures for the first time. Utilizing distance-dependent force and current spectroscopy, we quantify the exchange forces in comparison to the spin-polarization. For strongly spin-polarized tips, we distinguish different signs of the exchange force that we suggest arises from a change in exchange mechanisms between the probe and a skyrmion. This new approach may enable both nonperturbative readout combined with writing by current-driven reversal of atomic-scale magnets.

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.

Processing method for high resolution monochromator

International Nuclear Information System (INIS)

Kiriyama, Koji; Mitsui, Takaya

2006-12-01

A processing method for high resolution monochromator (HRM) has been developed at Japanese Atomic Energy Agency/Quantum Beam Science Directorate/Synchrotron Radiation Research unit at SPring-8. For manufacturing a HRM, a sophisticated slicing machine and X-ray diffractometer have been installed for shaping a crystal ingot and orienting precisely the surface of a crystal ingot, respectively. The specification of the slicing machine is following; Maximum size of a diamond blade is φ 350mm in diameter, φ 38.1mm in the spindle diameter, and 2mm in thickness. A large crystal such as an ingot with 100mm in diameter, 200mm in length can be cut. Thin crystal samples such as a wafer can be also cut using by another sample holder. Working distance of a main shaft with the direction perpendicular to working table in the machine is 350mm at maximum. Smallest resolution of the main shaft with directions of front-and-back and top-and-bottom are 0.001mm read by a digital encoder. 2mm/min can set for cutting samples in the forward direction. For orienting crystal faces relative to the blade direction adjustment, a one-circle goniometer and 2-circle segment are equipped on the working table in the machine. A rotation and a tilt of the stage can be done by manual operation. Digital encoder in a turn stage is furnished and has angle resolution of less than 0.01 degrees. In addition, a hand drill as a supporting device for detailed processing of crystal is prepared. Then, an ideal crystal face can be cut from crystal samples within an accuracy of about 0.01 degrees. By installation of these devices, a high energy resolution monochromator crystal for inelastic x-ray scattering and a beam collimator are got in hand and are expected to be used for nanotechnology studies. (author)

Measuring the hydrogen/deuterium exchange of proteins at high spatial resolution by mass spectrometry

DEFF Research Database (Denmark)

Rand, Kasper Dyrberg; Zehl, Martin; Jørgensen, Thomas J D

2014-01-01

, and eventually all of the protecting hydrogen bonds will transiently break as the protein-according to thermodynamic principles-cycles through partially unfolded states that correspond to excited free energy levels. As a result, all of the backbone amides will eventually become temporarily solvent....../dysfunction and conformational dynamics requires in many cases higher resolution and ultimately single-residue resolution. In this Account, we summarize our efforts to achieve single-residue deuterium levels in proteins by electron-based or laser-induced gas-phase fragmentation methods. A crucial analytical requirement...

A method for embedding granulated or spent ion-exchanging organic substances in concrete

International Nuclear Information System (INIS)

Christensen, H.; Jejes, P.

1976-01-01

A method of embedding in concrete a spent ion-exchanging organic substance originating from a scrubbing-circuit of a nuclear reactor Prior to solidification of the mixture, a substance is incorporated therewith said substance being capable of preventing water in the grains of the ion-exchanging substance from penetrating into the solidified product

Characterization of HEM silicon for solar cells. [Heat Exchanger Method

Science.gov (United States)

Dumas, K. A.; Khattak, C. P.; Schmid, F.

1981-01-01

The Heat Exchanger Method (HEM) is a promising low-cost ingot casting process for material used for solar cells. This is the only method that is capable of casting single crystal ingots with a square cross section using a directional solidification technique. This paper describes the chemical, mechanical and electrical properties of the HEM silicon material as a function of position within the ingot.

Hydrogen/deuterium exchange of multiply-protonated cytochrome c ions

International Nuclear Information System (INIS)

Wood, T.D.; Guan, Ziqiang; O'Connor, P.B.

1995-01-01

Low resolution measurements show gaseous multiply-protonated cytochrome c ions undergo hydrogen/deuterium (H/D) exchange with pseudo first-order kinetics at three distinct exchange levels, suggesting the co-existence of gaseous protein conformations. Although exchange levels first increase with increasing charge values, they decrease at the highest charge values, consistent with solution-phase behavior of cytochrome c, where the native structure unfolds with decreasing pH until folding into a compact A-state at lowest pH. High resolution measurements indicate the presence of at least six H/D exchange levels. Infrared (IR) laser heating and fast collisions via quadrupolar excitation (QE) increase H/D exchange levels (unfolding) while charge-stripping ions to lower charge values can increase or decrease H/D exchange levels (unfolding or folding). Wolynes has suggested studying proteins in vacuo could play an important role in delineating the contributions various forces play in the protein folding process, provided appropriate comparisons can be made between gas-phase and solution-phase structures

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

One-pot preparation of unsaturated polyester nanocomposites containing functionalized graphene sheets via a novel solvent-exchange method

Science.gov (United States)

This paper reports a convenient one-pot method integrating a novel solvent-exchange method into in situ melt polycondensation to fabricate unsaturated polyester nanocomposites containing functionalized graphene sheets (FGS). A novel solvent-exchange method was first developed to prepare graphene oxi...

A rule-based reference resolution method for Dutch discourse

NARCIS (Netherlands)

Harabagiu, S.; op den Akker, Hendrikus J.A.; Hospers, M.A.; Ferrandez, A.; Kroezen, Erna; Nijholt, Antinus; Lie, Danny

2002-01-01

This paper presents a knowledge-poor method for the solution of anaphoric and deictic expressions in Dutch texts. The method is developed for use in a text summarization system. Anaphora resolution plays an important role in the analysis of the original text as well as in the generation of the text

Cation Exchange Capacity of Biochar: An urgent method modification

Science.gov (United States)

Munera, Jose; Martinsen, Vegard; Mulder, Jan; Tau Strand, Line; Cornelissen, Gerard

2017-04-01

A better understanding of the cation exchange capacity (CEC) values of biochar and its acid neutralizing capacity (ANC) is crucial when tailoring a single biochar for a particular soil and crop. Literature values for the CEC of biochar are surprisingly variable, commonly ranging from 5 to 50 cmol+/Kg even as high as 69 to 204 cmol+/Kg and often poorly reproducible, suggesting methodological problems. Ashes and very fine pores in biochar may complicate the analysis and thus compromise the results. Here, we modify and critically assess different steps in a common method for CEC determination in biochar and investigate how the measured CEC may be affected by slow cation diffusion from micro-pores. We modified the existing ammonium acetate (NH4-OAc) method (buffered at pH 7), based on displaced ammonium (NH4+) in potassium chloride (KCl) extracts after removing excess NH4-OAc with alcohol in batch mode. We used pigeon pea biochar (produced at 350 ˚C; particle size 0.5mm to 2mm) to develop the method and we tested its reproducibility in biochars with different ANC. The biochar sample (1.00g) was pH-adjusted to 7 after 2 days of equilibration, using hydrochloric acid (HCl), and washed with water until the conductivity of the water was modified method were highly reproducible and that 1 day shaking with NH4OAc and KCl is enough to saturate the exchange sites with NH4+ and subsequently with K+. The biochar to NH4OAc solution ratio did not affect the measured CEC. Three washings with at least 15 ml alcohol are required to remove excess NH4-OAc. We found the CEC of biochar with the displacement method from pigeon pea, corncob, rice husk and cacao shell to be 26.4(±0.3), 19.2(±0.5), 20.5(±0.4), 46.5±(0.2) cmol+/Kg, respectively. The selected batch experiment allows a large sample throughput, less laboratory equipment is needed and shaking ensures better contact between the extracting solution and the exchange sites.

A Hydrogen Exchange Method Using Tritium and Sephadex: Its Application to Ribonuclease*

Science.gov (United States)

Englander, S. Walter

2012-01-01

A new method for measuring the hydrogen exchange of macromolecules in solution is described. The method uses tritium to trace the movement of hydrogen, and utilizes Sephadex columns to effect, in about 2 minutes, a separation between tritiated macromolecule and tritiated solvent great enough to allow the measurement of bound tritium. High sensitivity and freedom from artifact is demonstrated and the possible value of the technique for investigation of other kinds of colloid-small molecule interaction is indicated. Competition experiments involving tritium, hydrogen, and deuterium indicate the absence of any equilibrium isotope effect in the ribonuclease-hydrogen isotope system, though a secondary kinetic isotope effect is apparent when ribonuclease is largely deuterated. Ribonuclease shows four clearly distinguishable kinetic classes of exchangeable hydrogens. Evidence is marshaled to suggest the independently measurable classes II, III, and IV (in order of decreasing rate of exchange) to represent “random-chain” peptides, peptides involved in α-helix, and otherwise shielded side-chain and peptide hydrogens, respectively. PMID:14075117

Accessing High Spatial Resolution in Astronomy Using Interference Methods

Science.gov (United States)

Carbonel, Cyril; Grasset, Sébastien; Maysonnave, Jean

2018-04-01

In astronomy, methods such as direct imaging or interferometry-based techniques (Michelson stellar interferometry for example) are used for observations. A particular advantage of interferometry is that it permits greater spatial resolution compared to direct imaging with a single telescope, which is limited by diffraction owing to the aperture of the instrument as shown by Rueckner et al. in a lecture demonstration. The focus of this paper, addressed to teachers and/or students in high schools and universities, is to easily underline both an application of interferometry in astronomy and stress its interest for resolution. To this end very simple optical experiments are presented to explain all the concepts. We show how an interference pattern resulting from the combined signals of two telescopes allows us to measure the distance between two stars with a resolution beyond the diffraction limit. Finally this work emphasizes the breathtaking resolution obtained in state-of-the-art instruments such as the VLTi (Very Large Telescope interferometer).

Numerical simulation of two phase flows in heat exchangers

International Nuclear Information System (INIS)

Grandotto Biettoli, M.

2006-04-01

The author gives an overview of his research activity since 1981. He first gives a detailed presentation of properties and equations of two-phase flows in heat exchangers, and of their mathematical and numerical investigation: semi-local equations (mass conservation, momentum conservation and energy conservation), homogenized conservation equations (mass, momentum and enthalpy conservation, boundary conditions), equation closures, discretization, resolution algorithm, computational aspects and applications. Then, he reports the works performed in the field of turbulent flows, hyperbolic methods, low Mach methods, the Neptune project, and parallel computing

Evaluating the effect of remote sensing image spatial resolution on soil exchangeable potassium prediction models in smallholder farm settings.

Science.gov (United States)

Xu, Yiming; Smith, Scot E; Grunwald, Sabine; Abd-Elrahman, Amr; Wani, Suhas P

2017-09-15

Major end users of Digital Soil Mapping (DSM) such as policy makers and agricultural extension workers are faced with choosing the appropriate remote sensing data. The objective of this research is to analyze the spatial resolution effects of different remote sensing images on soil prediction models in two smallholder farms in Southern India called Kothapally (Telangana State), and Masuti (Karnataka State), and provide empirical guidelines to choose the appropriate remote sensing images in DSM. Bayesian kriging (BK) was utilized to characterize the spatial pattern of exchangeable potassium (K ex ) in the topsoil (0-15 cm) at different spatial resolutions by incorporating spectral indices from Landsat 8 (30 m), RapidEye (5 m), and WorldView-2/GeoEye-1/Pleiades-1A images (2 m). Some spectral indices such as band reflectances, band ratios, Crust Index and Atmospherically Resistant Vegetation Index from multiple images showed relatively strong correlations with soil K ex in two study areas. The research also suggested that fine spatial resolution WorldView-2/GeoEye-1/Pleiades-1A-based and RapidEye-based soil prediction models would not necessarily have higher prediction performance than coarse spatial resolution Landsat 8-based soil prediction models. The end users of DSM in smallholder farm settings need select the appropriate spectral indices and consider different factors such as the spatial resolution, band width, spectral resolution, temporal frequency, cost, and processing time of different remote sensing images. Overall, remote sensing-based Digital Soil Mapping has potential to be promoted to smallholder farm settings all over the world and help smallholder farmers implement sustainable and field-specific soil nutrient management scheme. Copyright © 2017 Elsevier Ltd. All rights reserved.

Impact of river stage prediction methods on stream-aquifer exchanges in a hydro(geo)logical model at the regional scale

Science.gov (United States)

Saleh, F.; Flipo, N.; de Fouquet, C.

2012-04-01

The main objective of this study is to provide a realistic simulation of river stage in regional river networks in order to improve the quantification of stream-aquifer exchanges and better assess the associated aquifer responses that are often impacted by the magnitude and the frequency of the river stage fluctuations. The study focuses on the Oise basin (17 000 km2, part of the 65 000 km2 Seine basin in Northern France) where stream-aquifer exchanges cannot be assessed directly by experimental methods. Nowadays numerical methods are the most appropriate approaches for assessing stream-aquifer exchanges at this scale. A regional distributed process-based hydro(geo)logical model, Eau-Dyssée, is used, which aims at the integrated modeling of the hydrosystem to manage the various elements involved in the quantitative and qualitative aspects of water resources. Eau-Dyssée simulates pseudo 3D flow in aquifer systems solving the diffusivity equation with a finite difference numerical scheme. River flow is simulated with a Muskingum model. In addition to the in-stream discharge, a river stage estimate is needed to calculate the water exchange at the stream-aquifer interface using the Darcy law. Three methods for assessing in-stream river stages are explored to determine the most appropriate representation at regional scale over 25 years (1980-2005). The first method consists in defining rating curves for each cell of a 1D Saint-Venant hydraulic model. The second method consists in interpolating observed rating curves (at gauging stations) onto the river cells of the hydro(geo)logical model. The interpolation technique is based on geostatistics. The last method assesses river stage using Manning equation with a simplified rectangular cross-section (water depth equals the hydraulic radius). Compared to observations, the geostatistical and the Manning methodologies lead to slightly less accurate (but still acceptable) results offering a low computational cost opportunity

Designed-walk replica-exchange method for simulations of complex systems

OpenAIRE

Urano, Ryo; Okamoto, Yuko

2015-01-01

We propose a new implementation of the replica-exchange method (REM) in which replicas follow a pre-planned route in temperature space instead of a random walk. Our method satisfies the detailed balance condition in the proposed route. The method forces tunneling events between the highest and lowest temperatures to happen with an almost constant period. The number of tunneling counts is proportional to that of the random-walk REM multiplied by the square root of moving distance in temperatur...

Validation of the method for determination of the thermal resistance of fouling in shell and tube heat exchangers

International Nuclear Information System (INIS)

Markowski, Mariusz; Trafczynski, Marian; Urbaniec, Krzysztof

2013-01-01

Highlights: • Heat recovery in a heat exchanger network (HEN). • A novel method for on-line determination of the thermal resistance of fouling is presented. • Details are developed for shell and tube heat exchangers. • The method was validated and sensibility analysis was carried out. • Developed approach allows long-term monitoring of changes in the HEN efficiency. - Abstract: A novel method for on-line determination of the thermal resistance of fouling in shell and tube heat exchangers is presented. It can be applied under the condition that the data on pressure, temperature, mass flowrate and thermophysical properties of both heat-exchanging media are continuously available. The calculation algorithm for use in the novel method is robust and ensures reliable determination of the thermal resistance of fouling even if the operating parameters fluctuate. The method was validated using measurement data retrieved from the operation records of a heat exchanger network connected with a crude distillation unit rated 800 t/h. Sensibility analysis of the method was carried out and the calculated values of the thermal resistance of fouling were critically reviewed considering the results of qualitative evaluation of fouling layers in the exchangers inspected during plant overhaul

Real-time hydrogen/deuterium exchange kinetics via supercharged electrospray ionization tandem mass spectrometry.

Science.gov (United States)

Sterling, Harry J; Williams, Evan R

2010-11-01

Amide hydrogen/deuterium exchange (HDX) rate constants of bovine ubiquitin in an ammonium acetate solution containing 1% of the electrospray ionization (ESI) "supercharging" reagent m-nitrobenzyl alcohol (m-NBA) were obtained using top-down, electron transfer dissociation (ETD) tandem mass spectrometry (MS). The supercharging reagent replaces the acid and temperature "quench" step in the conventional MS approach to HDX experiments by causing rapid protein denaturation to occur in the ESI droplet. The higher charge state ions that are produced with m-NBA are more unfolded, as measured by ion mobility, and result in higher fragmentation efficiency and higher sequence coverage with ETD. Single amino acid resolution was obtained for 44 of 72 exchangeable amide sites, and summed kinetic data were obtained for regions of the protein where adjacent fragment ions were not observed, resulting in an overall spatial resolution of 1.3 residues. Comparison of these results with previous values from NMR indicates that the supercharging reagent does not cause significant structural changes to the protein in the initial ESI solution and that scrambling or back-exchange is minimal. This new method for top-down HDX-MS enables real-time kinetic data measurements under physiological conditions, similar to those obtained using NMR, with comparable spatial resolution and significantly better sensitivity.

Comparison of Methods for Computing the Exchange Energy of quantum helium and hydrogen

International Nuclear Information System (INIS)

Cayao, J. L. C. D.

2009-01-01

I investigate approach methods to find the exchange energy for quantum helium and hydrogen. I focus on Heitler-London, Hund-Mullikan, Molecular Orbital and variational approach methods. I use Fock-Darwin states centered at the potential minima as the single electron wavefunctions. Using these we build Slater determinants as the basis for the two electron problem. I do a comparison of methods for two electron double dot (quantum hydrogen) and for two electron single dot (quantum helium) in zero and finite magnetic field. I show that the variational, Hund-Mullikan and Heitler-London methods are in agreement with the exact solutions. Also I show that the exchange energy calculation by Heitler-London (HL) method is an excellent approximation for large inter dot distances and for single dot in magnetic field is an excellent approximation the Variational method. (author)

Analytical method for high resolution liquid chromatography for quality control French Macaw

International Nuclear Information System (INIS)

Garcia Penna, Caridad M; Torres Amaro, Leonid; Menendez Castillo, Rosa; Sanchez, Esther; Martinez Espinosa, Vivian; Gonzalez, Maria Lidia; Rodriguez, Carlos

2007-01-01

Was developed and validated an analytical method for high resolution liquid chromatography applicable to quality control of drugs dry French Macaw (Senna alata L. Roxb.) With ultraviolet detection at 340 nm. The method for high resolution liquid chromatography used to quantify the sennosides A and B, main components, was validated and proved to be specific, linear, precise and accurate. (Author)

Considerations on the question of applying ion exchange or reverse osmosis methods in boiler feedwater processing

International Nuclear Information System (INIS)

Marquardt, K.; Dengler, H.

1976-01-01

This consideration is to show that the method of reverse osmosis presents in many cases an interesting and economical alternative to part and total desolination plants using ion exchangers. The essential advantages of the reverse osmosis are a higher degree of automization, no additional salting of the removed waste water, small constructional volume of the plant as well as favourable operational costs with increasing salt content of the crude water to be processed. As there is a relatively high salt breakthrough compared to the ion exchange method, the future tendency in boiler feedwater processing will be more towards a combination of methods of reverse osmosis and post-purification through continuous ion exchange methods. (orig./LH) [de

Improved methods for high resolution electron microscopy

Energy Technology Data Exchange (ETDEWEB)

Taylor, J.R.

1987-04-01

Existing methods of making support films for high resolution transmission electron microscopy are investigated and novel methods are developed. Existing methods of fabricating fenestrated, metal reinforced specimen supports (microgrids) are evaluated for their potential to reduce beam induced movement of monolamellar crystals of C/sub 44/H/sub 90/ paraffin supported on thin carbon films. Improved methods of producing hydrophobic carbon films by vacuum evaporation, and improved methods of depositing well ordered monolamellar paraffin crystals on carbon films are developed. A novel technique for vacuum evaporation of metals is described which is used to reinforce microgrids. A technique is also developed to bond thin carbon films to microgrids with a polymer bonding agent. Unique biochemical methods are described to accomplish site specific covalent modification of membrane proteins. Protocols are given which covalently convert the carboxy terminus of papain cleaved bacteriorhodopsin to a free thiol. 53 refs., 19 figs., 1 tab.

A fast and automatic mosaic method for high-resolution satellite images

Science.gov (United States)

Chen, Hongshun; He, Hui; Xiao, Hongyu; Huang, Jing

2015-12-01

We proposed a fast and fully automatic mosaic method for high-resolution satellite images. First, the overlapped rectangle is computed according to geographical locations of the reference and mosaic images and feature points on both the reference and mosaic images are extracted by a scale-invariant feature transform (SIFT) algorithm only from the overlapped region. Then, the RANSAC method is used to match feature points of both images. Finally, the two images are fused into a seamlessly panoramic image by the simple linear weighted fusion method or other method. The proposed method is implemented in C++ language based on OpenCV and GDAL, and tested by Worldview-2 multispectral images with a spatial resolution of 2 meters. Results show that the proposed method can detect feature points efficiently and mosaic images automatically.

A Numerical Algorithm and a Graphical Method to Size a Heat Exchanger

DEFF Research Database (Denmark)

Berning, Torsten

2011-01-01

This paper describes the development of a numerical algorithm and a graphical method that can be employed in order to determine the overall heat transfer coefficient inside heat exchangers. The method is based on an energy balance and utilizes the spreadsheet application software Microsoft Excel...

Combining Unsupervised and Supervised Statistical Learning Methods for Currency Exchange Rate Forecasting

OpenAIRE

Vasiljeva, Polina

2016-01-01

In this thesis we revisit the challenging problem of forecasting currency exchange rate. We combine machine learning methods such as agglomerative hierarchical clustering and random forest to construct a two-step approach for predicting movements in currency exchange prices of the Swedish krona and the US dollar. We use a data set with over 200 predictors comprised of different financial and macro-economic time series and their transformations. We perform forecasting for one week ahead with d...

Rapid and accurate processing method for amide proton exchange rate measurement in proteins

International Nuclear Information System (INIS)

Koskela, Harri; Heikkinen, Outi; Kilpelaeinen, Ilkka; Heikkinen, Sami

2007-01-01

Exchange between protein backbone amide hydrogen and water gives relevant information about solvent accessibility and protein secondary structure stability. NMR spectroscopy provides a convenient tool to study these dynamic processes with saturation transfer experiments. Processing of this type of NMR spectra has traditionally required peak integration followed by exponential fitting, which can be tedious with large data sets. We propose here a computer-aided method that applies inverse Laplace transform in the exchange rate measurement. With this approach, the determination of exchange rates can be automated, and reliable results can be acquired rapidly without a need for manual processing

Determination of Backbone Amide Hydrogen Exchange Rates of Cytochrome c Using Partially Scrambled Electron Transfer Dissociation Data

Science.gov (United States)

Hamuro, Yoshitomo; E, Sook Yen

2018-05-01

The technological goal of hydrogen/deuterium exchange-mass spectrometry (HDX-MS) is to determine backbone amide hydrogen exchange rates. The most critical challenge to achieve this goal is obtaining the deuterium incorporation in single-amide resolution, and gas-phase fragmentation may provide a universal solution. The gas-phase fragmentation may generate the daughter ions which differ by a single amino acid and the difference in deuterium incorporations in the two analogous ions can yield the deuterium incorporation at the sub-localized site. Following the pioneering works by Jørgensen and Rand, several papers utilized the electron transfer dissociation (ETD) to determine the location of deuterium in single-amide resolution. This paper demonstrates further advancement of the strategy by determining backbone amide hydrogen exchange rates, instead of just determining deuterium incorporation at a single time point, in combination with a wide time window monitoring. A method to evaluate the effects of scrambling and to determine the exchange rates from partially scrambled HDX-ETD-MS data is described. All parent ions for ETD fragmentation were regio-selectively scrambled: The deuterium in some regions of a peptide ion was scrambled while that in the other regions was not scrambled. The method determined 31 backbone amide hydrogen exchange rates of cytochrome c in the non-scrambled regions. Good fragmentation of a parent ion, a low degree of scrambling, and a low number of exchangeable hydrogens in the preceding side chain are the important factors to determine the exchange rate. The exchange rates determined by the HDX-MS are in good agreement with those determined by NMR. [Figure not available: see fulltext.

Determination of Backbone Amide Hydrogen Exchange Rates of Cytochrome c Using Partially Scrambled Electron Transfer Dissociation Data.

Science.gov (United States)

Hamuro, Yoshitomo; E, Sook Yen

2018-05-01

The technological goal of hydrogen/deuterium exchange-mass spectrometry (HDX-MS) is to determine backbone amide hydrogen exchange rates. The most critical challenge to achieve this goal is obtaining the deuterium incorporation in single-amide resolution, and gas-phase fragmentation may provide a universal solution. The gas-phase fragmentation may generate the daughter ions which differ by a single amino acid and the difference in deuterium incorporations in the two analogous ions can yield the deuterium incorporation at the sub-localized site. Following the pioneering works by Jørgensen and Rand, several papers utilized the electron transfer dissociation (ETD) to determine the location of deuterium in single-amide resolution. This paper demonstrates further advancement of the strategy by determining backbone amide hydrogen exchange rates, instead of just determining deuterium incorporation at a single time point, in combination with a wide time window monitoring. A method to evaluate the effects of scrambling and to determine the exchange rates from partially scrambled HDX-ETD-MS data is described. All parent ions for ETD fragmentation were regio-selectively scrambled: The deuterium in some regions of a peptide ion was scrambled while that in the other regions was not scrambled. The method determined 31 backbone amide hydrogen exchange rates of cytochrome c in the non-scrambled regions. Good fragmentation of a parent ion, a low degree of scrambling, and a low number of exchangeable hydrogens in the preceding side chain are the important factors to determine the exchange rate. The exchange rates determined by the HDX-MS are in good agreement with those determined by NMR. Graphical Abstract ᅟ.

Determination of Backbone Amide Hydrogen Exchange Rates of Cytochrome c Using Partially Scrambled Electron Transfer Dissociation Data

Science.gov (United States)

Hamuro, Yoshitomo; E, Sook Yen

2018-03-01

The technological goal of hydrogen/deuterium exchange-mass spectrometry (HDX-MS) is to determine backbone amide hydrogen exchange rates. The most critical challenge to achieve this goal is obtaining the deuterium incorporation in single-amide resolution, and gas-phase fragmentation may provide a universal solution. The gas-phase fragmentation may generate the daughter ions which differ by a single amino acid and the difference in deuterium incorporations in the two analogous ions can yield the deuterium incorporation at the sub-localized site. Following the pioneering works by Jørgensen and Rand, several papers utilized the electron transfer dissociation (ETD) to determine the location of deuterium in single-amide resolution. This paper demonstrates further advancement of the strategy by determining backbone amide hydrogen exchange rates, instead of just determining deuterium incorporation at a single time point, in combination with a wide time window monitoring. A method to evaluate the effects of scrambling and to determine the exchange rates from partially scrambled HDX-ETD-MS data is described. All parent ions for ETD fragmentation were regio-selectively scrambled: The deuterium in some regions of a peptide ion was scrambled while that in the other regions was not scrambled. The method determined 31 backbone amide hydrogen exchange rates of cytochrome c in the non-scrambled regions. Good fragmentation of a parent ion, a low degree of scrambling, and a low number of exchangeable hydrogens in the preceding side chain are the important factors to determine the exchange rate. The exchange rates determined by the HDX-MS are in good agreement with those determined by NMR. [Figure not available: see fulltext.

Heat exchanger device and method for heat removal or transfer

Science.gov (United States)

Koplow, Jeffrey P

2013-12-10

Systems and methods for a forced-convection heat exchanger are provided. In one embodiment, heat is transferred to or from a thermal load in thermal contact with a heat conducting structure, across a narrow air gap, to a rotating heat transfer structure immersed in a surrounding medium such as air.

A simplified method of calculating heat flow through a two-phase heat exchanger

Energy Technology Data Exchange (ETDEWEB)

Yohanis, Y.G. [Thermal Systems Engineering Group, Faculty of Engineering, University of Ulster, Newtownabbey, Co Antrim, BT37 0QB Northern Ireland (United Kingdom)]. E-mail: yg.yohanis@ulster.ac.uk; Popel, O.S. [Non-traditional Renewable Energy Sources, Institute for High Temperatures, Russian Academy of Sciences, 13/19 Izhorskaya str., IVTAN, Moscow 125412 (Russian Federation); Frid, S.E. [Non-traditional Renewable Energy Sources, Institute for High Temperatures, Russian Academy of Sciences, 13/19 Izhorskaya str., IVTAN, Moscow 125412 (Russian Federation)

2005-10-01

A simplified method of calculating the heat flow through a heat exchanger in which one or both heat carrying media are undergoing a phase change is proposed. It is based on enthalpies of the heat carrying media rather than their temperatures. The method enables the determination of the maximum rate of heat flow provided the thermodynamic properties of both heat-carrying media are known. There will be no requirement to separately simulate each part of the system or introduce boundaries within the heat exchanger if one or both heat-carrying media undergo a phase change. The model can be used at the pre-design stage, when the parameters of the heat exchangers may not be known, i.e., to carry out an assessment of a complex energy scheme such as a steam power plant. One such application of this model is in thermal simulation exercises within the TRNSYS modeling environment.

A simplified method of calculating heat flow through a two-phase heat exchanger

International Nuclear Information System (INIS)

Yohanis, Y.G.; Popel, O.S.; Frid, S.E.

2005-01-01

A simplified method of calculating the heat flow through a heat exchanger in which one or both heat carrying media are undergoing a phase change is proposed. It is based on enthalpies of the heat carrying media rather than their temperatures. The method enables the determination of the maximum rate of heat flow provided the thermodynamic properties of both heat-carrying media are known. There will be no requirement to separately simulate each part of the system or introduce boundaries within the heat exchanger if one or both heat-carrying media undergo a phase change. The model can be used at the pre-design stage, when the parameters of the heat exchangers may not be known, i.e., to carry out an assessment of a complex energy scheme such as a steam power plant. One such application of this model is in thermal simulation exercises within the TRNSYS modeling environment

A Numerical Algorithm and a Graphical Method to Size a Heat Exchanger

DEFF Research Database (Denmark)

Berning, Torsten

2011-01-01

This paper describes the development of a numerical algorithm and a graphical method that can be employed in order to determine the overall heat transfer coefficient inside heat exchangers. The method is based on an energy balance and utilizes the spreadsheet application software Microsoft ExcelTM...

Performance of adsorbent-embedded heat exchangers using binder-coating method

KAUST Repository

Li, Ang

2016-01-01

The performance of adsorption (AD) chillers or desalination cycles is dictated by the rates of heat and mass transfer of adsorbate in adsorbent-packed beds. Conventional granular-adsorbent, packed in fin-tube heat exchangers, suffered from poor heat transfer in heating (desorption) or cooling (adsorption) processes of the batch-operated cycles, with undesirable performance parameters such as higher footprint of plants, low coefficient of performance (COP) of AD cycles and higher capital cost of the machines. The motivation of present work is to mitigate the heat and mass "bottlenecks" of fin-tube heat exchangers by using a powdered-adsorbent cum binder coated onto the fin surfaces of exchangers. Suitable adsorbent-binder pairs have been identified for the silica gel adsorbent with pore surface areas up to 680 m2/g and pore diameters less than 6 nm. The parent silica gel remains largely unaffected despite being pulverized into fine particles of 100 μm, and yet maintaining its water uptake characteristics. The paper presents an experimental study on the selection and testing processes to achieve high efficacy of adsorbent-binder coated exchangers. The test results indicate 3.4-4.6 folds improvement in heat transfer rates over the conventional granular-packed method, resulting a faster rate of water uptake by 1.5-2 times on the suitable silica gel type. © 2015 Elsevier Ltd. All rights reserved.

Multiyear high-resolution carbon exchange over European croplands from the integration of observed crop yields into CarbonTracker Europe

Science.gov (United States)

Combe, Marie; Vilà-Guerau de Arellano, Jordi; de Wit, Allard; Peters, Wouter

2016-04-01

Carbon exchange over croplands plays an important role in the European carbon cycle over daily-to-seasonal time scales. Not only do crops occupy one fourth of the European land area, but their photosynthesis and respiration are large and affect CO2 mole fractions at nearly every atmospheric CO2 monitoring site. A better description of this crop carbon exchange in our CarbonTracker Europe data assimilation system - which currently treats crops as unmanaged grasslands - could strongly improve its ability to constrain terrestrial carbon fluxes. Available long-term observations of crop yield, harvest, and cultivated area allow such improvements, when combined with the new crop-modeling framework we present. This framework can model the carbon fluxes of 10 major European crops at high spatial and temporal resolution, on a 12x12 km grid and 3-hourly time-step. The development of this framework is threefold: firstly, we optimize crop growth using the process-based WOrld FOod STudies (WOFOST) agricultural crop growth model. Simulated yields are downscaled to match regional crop yield observations from the Statistical Office of the European Union (EUROSTAT) by estimating a yearly regional parameter for each crop species: the yield gap factor. This step allows us to better represent crop phenology, to reproduce the observed multiannual European crop yields, and to construct realistic time series of the crop carbon fluxes (gross primary production, GPP, and autotrophic respiration, Raut) on a fine spatial and temporal resolution. Secondly, we combine these GPP and Raut fluxes with a simple soil respiration model to obtain the total ecosystem respiration (TER) and net ecosystem exchange (NEE). And thirdly, we represent the horizontal transport of carbon that follows crop harvest and its back-respiration into the atmosphere during harvest consumption. We distribute this carbon using observations of the density of human and ruminant populations from EUROSTAT. We assess the model

Relevance of traditional methods of conflict resolution in the justice ...

African Journals Online (AJOL)

The traditional methods of African conflict resolution have long existed and are deeply rooted in the customs and traditions of the peoples of Africa. These methods are geared towards maintaining harmonious and peaceful coexistence in the community. Colonialism introduced the modern justice system, which dominated ...

A Method for Retrieving Daily Land Surface Albedo from Space at 30-m Resolution

Directory of Open Access Journals (Sweden)

Bo Gao

2015-08-01

Full Text Available Land surface albedo data with high spatio-temporal resolution are increasingly important for scientific studies addressing spatially and/or temporally small-scale phenomena, such as urban heat islands and urban land surface energy balance. Our previous study derived albedo data with 2–4-day and 30-m temporal and spatial resolution that have better spatio-temporal resolution than existing albedo data, but do not completely satisfy the requirements for monitoring high-frequency land surface changes at the small scale. Downscaling technology provides a chance to further improve the albedo data spatio-temporal resolution and accuracy. This paper introduces a method that combines downscaling technology for land surface reflectance with an empirical method of deriving land surface albedo. Firstly, downscaling daily MODIS land surface reflectance data (MOD09GA from 500 m to 30 m on the basis of HJ-1A/B BRDF data with 2–4-day and 30-m temporal and spatial resolution is performed: this is the key step in the improved method. Subsequently, the daily 30-m land surface albedo data are derived by an empirical method combining prior knowledge of the MODIS BRDF product and the downscaled daily 30-m reflectance. Validation of albedo data obtained using the proposed method shows that the new method has both improved spatio-temporal resolution and good accuracy (a total absolute accuracy of 0.022 and a total root mean squared error at six sites of 0.028.

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

Temporal super resolution using variational methods

DEFF Research Database (Denmark)

Keller, Sune Høgild; Lauze, Francois Bernard; Nielsen, Mads

2010-01-01

Temporal super resolution (TSR) is the ability to convert video from one frame rate to another and is as such a key functionality in modern video processing systems. A higher frame rate than what is recorded is desired for high frame rate displays, for super slow-motion, and for video/film format...... observed when watching video on large and bright displays where the motion of high contrast edges often seem jerky and unnatural. A novel motion compensated (MC) TSR algorithm using variational methods for both optical flow calculation and the actual new frame interpolation is presented. The flow...

Method of detecting defects in ion exchange membranes of electrochemical cells by chemochromic sensors

Science.gov (United States)

Brooker, Robert Paul; Mohajeri, Nahid

2016-01-05

A method of detecting defects in membranes such as ion exchange membranes of electrochemical cells. The electrochemical cell includes an assembly having an anode side and a cathode side with the ion exchange membrane in between. In a configuration step a chemochromic sensor is placed above the cathode and flow isolation hardware lateral to the ion exchange membrane which prevents a flow of hydrogen (H.sub.2) between the cathode and anode side. The anode side is exposed to a first reactant fluid including hydrogen. The chemochromic sensor is examined after the exposing for a color change. A color change evidences the ion exchange membrane has at least one defect that permits H.sub.2 transmission therethrough.

Assessment of modern spectral analysis methods to improve wavenumber resolution of F-K spectra

International Nuclear Information System (INIS)

Shirley, T.E.; Laster, S.J.; Meek, R.A.

1987-01-01

The improvement in wavenumber spectra obtained by using high resolution spectral estimators is examined. Three modern spectral estimators were tested, namely the Autoregressive/Maximum Entropy (AR/ME) method, the Extended Prony method, and an eigenstructure method. They were combined with the conventional Fourier method by first transforming each trace with a Fast Fourier Transform (FFT). A high resolution spectral estimator was applied to the resulting complex spatial sequence for each frequency. The collection of wavenumber spectra thus computed comprises a hybrid f-k spectrum with high wavenumber resolution and less spectral ringing. Synthetic and real data records containing 25 traces were analyzed by using the hybrid f-k method. The results show an FFT-AR/ME f-k spectrum has noticeably better wavenumber resolution and more spectral dynamic range than conventional spectra when the number of channels is small. The observed improvement suggests the hybrid technique is potentially valuable in seismic data analysis

The sky blue method as a screening test to detect misplacement of percutaneous endoscopic gastrostomy tube at exchange.

Science.gov (United States)

Suzuki, Yutaka; Urashima, Mitsuyoshi; Yoshida, Hideki; Iwase, Tsuyoshi; Kura, Toshiroh; Imazato, Shin; Kudo, Michiaki; Ohta, Tomoyuki; Mizuhara, Akihiro; Tamamori, Yutaka; Muramatsu, Hirohito; Nishiguchi, Yukio; Nishiyama, Yorihiro; Takahashi, Mikako; Nishiwaki, Shinji; Matsumoto, Masami; Goshi, Satoshi; Sakamoto, Shigeo; Uchida, Nobuyuki; Ijima, Masashi; Ogawa, Tetsushi; Shimazaki, Makoto; Takei, Shinichi; Kimura, Chikou; Yamashita, Satoyoshi; Endo, Takao; Nakahori, Masato; Itoh, Akihiko; Kusakabe, Toshiro; Ishizuka, Izumi; Iiri, Takao; Fukasawa, Shingo; Arimoto, Yukitsugu; Kajitani, Nobuaki; Ishida, Kazuhiko; Onishi, Koji; Taira, Akihiko; Kobayashi, Makoto; Itano, Yasuto; Kobuke, Toshiya

2009-01-01

During tube exchange for percutaneous endoscopic gastrostomy (PEG), a misplaced tube can cause peritonitis and death. Thus, endoscopic or radiologic observation is required at tube exchange to make sure the tube is placed correctly. However, these procedures cost extensive time and money to perform in all patients at the time of tube exchange. Therefore, we developed the "sky blue method" as a screening test to detect misplacement of the PEG tube during tube exchange. First, sky blue solution consisting of indigocarmine diluted with saline was injected into the gastric space via the old PEG tube just before the tube exchange. Next, the tube was exchanged using a standard method. Then, we checked whether the sky blue solution could be collected through the new tube or not. Finally, we confirmed correct placement of the tube by endoscopic or radiologic observation for all patients. A total of 961 patients were enrolled. Each tube exchange took 1 to 3 minutes, and there were no adverse effects. Four patients experienced a misplaced tube, all of which were detectable with the sky blue method. Diagnostic parameters of the sky blue method were as follows: sensitivity, 94% (95%CI: 92-95%); specificity, 100% (95%CI: 40-100%); positive predictive value, 100% (95%CI: 100-100%); negative predictive value, 6% (95%CI: 2-16%). These results suggest that the number of endoscopic or radiologic observations to confirm correct replacement of the PEG tube may be reduced to one fifteenth using the sky blue method.

Initial results from a charge exchange q-diagnostic on TEXT-U

International Nuclear Information System (INIS)

Valanju, P.M.; Duraiappah, L.; Bengtson, R.D.; Karzhavin, Y.; Nikitin, A.

1994-01-01

The authors present initial results from a new q-diagnostic for TEXT-Upgrade. This method is based on using a toroidal array of detectors to determine the plane in which beam-injected neutrals are emitted after two charge-exchange collisions. The potential advantages are low cost, full plasma accessibility, and good time resolution. Their initial series of experiments on TEXT-U established the feasibility of this technique

Comparative analysis of different methods in mathematical modelling of the recuperative heat exchangers

International Nuclear Information System (INIS)

Debeljkovic, D.Lj.; Stevic, D.Z.; Simeunovic, G.V.; Misic, M.A.

2015-01-01

The heat exchangers are frequently used as constructive elements in various plants and their dynamics is very important. Their operation is usually controlled by manipulating inlet fluid temperatures or mass flow rates. On the basis of the accepted and critically clarified assumptions, a linearized mathematical model of the cross-flow heat exchanger has been derived, taking into account the wall dynamics. The model is based on the fundamental law of energy conservation, covers all heat accumulation storages in the process, and leads to the set of partial differential equations (PDE), which solution is not possible in closed form. In order to overcome the solutions difficulties in this paper are analyzed different methods for modeling the heat exchanger: approach based on Laplace transformation, approximation of partial differential equations based on finite differences, the method of physical discretization and the transport approach. Specifying the input temperatures and output variables, under the constant initial conditions, the step transient responses have been simulated and presented in graphic form in order to compare these results for the four characteristic methods considered in this paper, and analyze its practical significance. (author)

Group IV nanocrystals with ion-exchangeable surface ligands and methods of making the same

Science.gov (United States)

Wheeler, Lance M.; Nichols, Asa W.; Chernomordik, Boris D.; Anderson, Nicholas C.; Beard, Matthew C.; Neale, Nathan R.

2018-01-09

Methods are described that include reacting a starting nanocrystal that includes a starting nanocrystal core and a covalently bound surface species to create an ion-exchangeable (IE) nanocrystal that includes a surface charge and a first ion-exchangeable (IE) surface ligand ionically bound to the surface charge, where the starting nanocrystal core includes a group IV element.

FFT-enhanced IHS transform method for fusing high-resolution satellite images

Science.gov (United States)

Ling, Y.; Ehlers, M.; Usery, E.L.; Madden, M.

2007-01-01

Existing image fusion techniques such as the intensity-hue-saturation (IHS) transform and principal components analysis (PCA) methods may not be optimal for fusing the new generation commercial high-resolution satellite images such as Ikonos and QuickBird. One problem is color distortion in the fused image, which causes visual changes as well as spectral differences between the original and fused images. In this paper, a fast Fourier transform (FFT)-enhanced IHS method is developed for fusing new generation high-resolution satellite images. This method combines a standard IHS transform with FFT filtering of both the panchromatic image and the intensity component of the original multispectral image. Ikonos and QuickBird data are used to assess the FFT-enhanced IHS transform method. Experimental results indicate that the FFT-enhanced IHS transform method may improve upon the standard IHS transform and the PCA methods in preserving spectral and spatial information. ?? 2006 International Society for Photogrammetry and Remote Sensing, Inc. (ISPRS).

A new high-resolution electromagnetic method for subsurface imaging

Science.gov (United States)

Feng, Wanjie

For most electromagnetic (EM) geophysical systems, the contamination of primary fields on secondary fields ultimately limits the capability of the controlled-source EM methods. Null coupling techniques were proposed to solve this problem. However, the small orientation errors in the null coupling systems greatly restrict the applications of these systems. Another problem encountered by most EM systems is the surface interference and geologic noise, which sometimes make the geophysical survey impossible to carry out. In order to solve these problems, the alternating target antenna coupling (ATAC) method was introduced, which greatly removed the influence of the primary field and reduced the surface interference. But this system has limitations on the maximum transmitter moment that can be used. The differential target antenna coupling (DTAC) method was proposed to allow much larger transmitter moments and at the same time maintain the advantages of the ATAC method. In this dissertation, first, the theoretical DTAC calculations were derived mathematically using Born and Wolf's complex magnetic vector. 1D layered and 2D blocked earth models were used to demonstrate that the DTAC method has no responses for 1D and 2D structures. Analytical studies of the plate model influenced by conductive and resistive backgrounds were presented to explain the physical phenomenology behind the DTAC method, which is the magnetic fields of the subsurface targets are required to be frequency dependent. Then, the advantages of the DTAC method, e.g., high-resolution, reducing the geologic noise and insensitive to surface interference, were analyzed using surface and subsurface numerical examples in the EMGIMA software. Next, the theoretical advantages, such as high resolution and insensitive to surface interference, were verified by designing and developing a low-power (moment of 50 Am 2) vertical-array DTAC system and testing it on controlled targets and scaled target coils. At last, a

Method of separating radioactive nuclides from ion exchange resins

International Nuclear Information System (INIS)

Suzuki, Kazunori; Saikoku, Masami; Taneta, Daisuke; Yagi, Takuro.

1987-01-01

Purpose: To enable to safely process radioactive nuclides from spent ion exchange resins by using existent processing facilities. Method: Ion exchange resins in aqueous medium are at first placed to the ultrasonic wave irradiation site and put into such a state where clads and resins are easily separatable from each other by weakening the bonding force between them. Since the clads are magnetic material such as Fe 3 O 4 or NiFe 2 O 4 , the clads can be collected in the direction of the magnetic force by exerting the magnetic field simultaneously. The collected clads are transported by means of the aqueous medium to a collecting tank by removing the effect of magnetic field, for example, by interrupting the current supply to the electromagnet. Finally, they were subjected to stabilization and fixation into inorganic hardening agent such as cement hardener. Thus, processions can be made safely by using existent facilities. (Takahashi, M.)

Applying multi-resolution numerical methods to geodynamics

Science.gov (United States)

Davies, David Rhodri

Computational models yield inaccurate results if the underlying numerical grid fails to provide the necessary resolution to capture a simulation's important features. For the large-scale problems regularly encountered in geodynamics, inadequate grid resolution is a major concern. The majority of models involve multi-scale dynamics, being characterized by fine-scale upwelling and downwelling activity in a more passive, large-scale background flow. Such configurations, when coupled to the complex geometries involved, present a serious challenge for computational methods. Current techniques are unable to resolve localized features and, hence, such models cannot be solved efficiently. This thesis demonstrates, through a series of papers and closely-coupled appendices, how multi-resolution finite-element methods from the forefront of computational engineering can provide a means to address these issues. The problems examined achieve multi-resolution through one of two methods. In two-dimensions (2-D), automatic, unstructured mesh refinement procedures are utilized. Such methods improve the solution quality of convection dominated problems by adapting the grid automatically around regions of high solution gradient, yielding enhanced resolution of the associated flow features. Thermal and thermo-chemical validation tests illustrate that the technique is robust and highly successful, improving solution accuracy whilst increasing computational efficiency. These points are reinforced when the technique is applied to geophysical simulations of mid-ocean ridge and subduction zone magmatism. To date, successful goal-orientated/error-guided grid adaptation techniques have not been utilized within the field of geodynamics. The work included herein is therefore the first geodynamical application of such methods. In view of the existing three-dimensional (3-D) spherical mantle dynamics codes, which are built upon a quasi-uniform discretization of the sphere and closely coupled

Separation of uranium from sodium carbonate - sodium bicarbonate eluate by ion exchange method

International Nuclear Information System (INIS)

Sakane, Kohji; Hirotsu, Takahiro; Fujii, Ayako; Katoh, Shunsaku; Sugasaka, Kazuhiko

1982-01-01

The ion exchange method was used for separating uranium from the eluate (0.5 N Na 2 CO 3 -0.5 N NaHCO 3 ) that was obtained in the extraction process of uranium from natural sea water by using the titanium-activated carbon composite adsorbent. Uranium in the eluate containing 3 mg/1 uranium was adsorbed by ion exchange resin (Amberlite IRA-400), and was eluted with the eluant (5 % NaCl-0.5 % Na 2 CO 3 ). The concentration ratio of uranium in the final concentrated-eluate became more than 20 times. The eluting solution to the adsorbent and the eluant to the resin could be repeatedly used in the desorption-ion exchange process. Sodium carbonate was consumed at the desorption step, and sodium bicarbonate was consumed at the ion exchange step. The concentration ratio of uranium was found to decrease as chloride ion in the eluate increased. (author)

Separation of uranium from sodium carbonate-sodium bicarbonate eluate by ion exchange method

International Nuclear Information System (INIS)

Sakane, Kohji; Hirotsu, Takahiro; Fujii, Ayako; Katoh, Shunsaku; Sugasaka, Kazuhiko

1982-01-01

The ion exchange method was used for separating uranium from the eluate (0.5 N Na 2 CO 3 -0.5 N NaHCO 3 ) that was obtained in the extraction process of uranium from natural sea water by using the titanium-activated carbon composite adsorbent. Uranium in the eluate containing 3 mg/l uranium was adsorbed by ion exchange resin (Amberlite IRA-400), and was eluted with the eluent (5% NaCl-0.5% Na 2 CO 3 ). The concentration ratio of uranium in the final concentrated-eluate became more than 20 times. The eluting solution to the adsorbent and the eluant to the resin could be repeatedly used in the desorption-ion exchange process. Sodium carbonate was consumed at the desorption step, and sodium bicarbonate was consumed at the ion exchange step. The concentration ratio of uranium was found to decrease as chloride ion in the eluate increased. (author)

Hydrogen-tritium exchange survey of allosteric effects in hemoglobin

International Nuclear Information System (INIS)

Englander, J.J.; Englander, S.W.

1987-01-01

The oxy and deoxy forms of hemoglobin display major differences in H-exchange behavior. Hydrogen-tritium exchange experiments on hemoglobin were performed in the low-resolution mode to observe the dependence of these differences on pH (Bohr effect), organic phosphates, and salt. Unlike a prior report, increasing pH was found to decrease the oxy-deoxy difference monotonically, in general accordance with the alkaline Bohr effect. A prior report that the H-exchange difference between oxy- and deoxyhemoglobin vanishes at pH 9, and thus appears to reflect the Bohr effect alone, was found to be due to the borate buffer used, which at high pH tends to abolish the oxy-deoxy difference in a limited region of the H-exchange curve. Effects on hemoglobin H exchange due to organic phosphates parallel the differential binding of these agents (inositol hexaphosphate more than diphosphoglycerate, deoxy more than oxy, at low pH more than at high pH). Added salt slows H exchange of deoxyhemoglobin and has no effect on the oxy form. These results display the sensitivity of simple H-exchange measurements for finding and characterizing effects on structure and dynamics that may occur anywhere in the protein and help to define conditions for higher resolution approaches that can localize the changes observed

High-resolution X-ray crystal structure of bovine H-protein using the high-pressure cryocooling method

International Nuclear Information System (INIS)

Higashiura, Akifumi; Ohta, Kazunori; Masaki, Mika; Sato, Masaru; Inaka, Koji; Tanaka, Hiroaki; Nakagawa, Atsushi

2013-01-01

Using the high-pressure cryocooling method, the high-resolution X-ray crystal structure of bovine H-protein was determined at 0.86 Å resolution. This is the first ultra-high-resolution structure obtained from a high-pressure cryocooled crystal. Recently, many technical improvements in macromolecular X-ray crystallography have increased the number of structures deposited in the Protein Data Bank and improved the resolution limit of protein structures. Almost all high-resolution structures have been determined using a synchrotron radiation source in conjunction with cryocooling techniques, which are required in order to minimize radiation damage. However, optimization of cryoprotectant conditions is a time-consuming and difficult step. To overcome this problem, the high-pressure cryocooling method was developed (Kim et al., 2005 ▶) and successfully applied to many protein-structure analyses. In this report, using the high-pressure cryocooling method, the X-ray crystal structure of bovine H-protein was determined at 0.86 Å resolution. Structural comparisons between high- and ambient-pressure cryocooled crystals at ultra-high resolution illustrate the versatility of this technique. This is the first ultra-high-resolution X-ray structure obtained using the high-pressure cryocooling method

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.

An efficient method based on the uniformity principle for synthesis of large-scale heat exchanger networks

International Nuclear Information System (INIS)

Zhang, Chunwei; Cui, Guomin; Chen, Shang

2016-01-01

Highlights: • Two dimensionless uniformity factors are presented to heat exchange network. • The grouping of process streams reduces the computational complexity of large-scale HENS problems. • The optimal sub-network can be obtained by Powell particle swarm optimization algorithm. • The method is illustrated by a case study involving 39 process streams, with a better solution. - Abstract: The optimal design of large-scale heat exchanger networks is a difficult task due to the inherent non-linear characteristics and the combinatorial nature of heat exchangers. To solve large-scale heat exchanger network synthesis (HENS) problems, two dimensionless uniformity factors to describe the heat exchanger network (HEN) uniformity in terms of the temperature difference and the accuracy of process stream grouping are deduced. Additionally, a novel algorithm that combines deterministic and stochastic optimizations to obtain an optimal sub-network with a suitable heat load for a given group of streams is proposed, and is named the Powell particle swarm optimization (PPSO). As a result, the synthesis of large-scale heat exchanger networks is divided into two corresponding sub-parts, namely, the grouping of process streams and the optimization of sub-networks. This approach reduces the computational complexity and increases the efficiency of the proposed method. The robustness and effectiveness of the proposed method are demonstrated by solving a large-scale HENS problem involving 39 process streams, and the results obtained are better than those previously published in the literature.

A method for measuring exchange stiffness in ferromagnetic films

International Nuclear Information System (INIS)

Girt, Erol; Huttema, W.; Montoya, E.; Kardasz, B.; Eyrich, C.; Heinrich, B.; Mryasov, O. N.; Dobin, A. Yu.; Karis, O.

2011-01-01

An exchange stiffness, A ex , in ferromagnetic films is obtained by fitting the M(H) dependence of two ferromagnetic layers antiferromagnetically coupled across a nonmagnetic spacer layer with a simple micromagnetic model. In epitaxial and textured structures this method allows measuring A ex between the crystallographic planes perpendicular to the growth direction of ferromagnetic films. Our results show that A ex between [0001] planes in textured Co grains is 1.54 ± 0.12 x 10 -11 J/m.

The advanced CECE process for enriching tritium by the chemical exchange method with a hydrophobic catalyst

International Nuclear Information System (INIS)

Kitamoto, Asashi; Shimizu, Masami; Masui, Takashi.

1992-01-01

The monothermal chemical exchange process with electrolysis, i.e., CECE process, was an effective method for enriching and removing tritium from tritiated water with low to middle level activity. The purpose of this study is to propose the theoretical background of the two-parameter evaluation method, which is based on a two-step isotope exchange reaction between hydrogen gas and liquid water, for improvement of the performance of a hydrophobic catalyst by a trickle bed-type column. Finally, a two-parameter method could attain the highest performance of isotope separation and the lowest liquid holdup for a trickle bed-type column. Therefore, this method will present some effective and practical procedures in scaling up a tritium enrichment process. The main aspect of the CECE process in engineering design and system evaluation was to develop the isotope exchange column with a high performance catalyst. (author)

Comparison of neutronic transport equation resolution nodal methods

International Nuclear Information System (INIS)

Zamonsky, O.M.; Gho, C.J.

1990-01-01

In this work, some transport equation resolution nodal methods are comparatively studied: the constant-constant (CC), linear-nodal (LN) and the constant-quadratic (CQ). A nodal scheme equivalent to finite differences has been used for its programming, permitting its inclusion in existing codes. Some bidimensional problems have been solved, showing that linear-nodal (LN) are, in general, obtained with accuracy in CPU shorter times. (Author) [es

Separation of uranium from sodium carbonate - sodium bicarbonate eluate by ion exchange method

Energy Technology Data Exchange (ETDEWEB)

Sakane, Kohji; Hirotsu, Takahiro; Fujii, Ayako; Katoh, Shunsaku; Sugasaka, Kazuhiko (Government Industrial Research Inst., Shikoku, Takamatsu (Japan))

1982-09-01

The ion exchange method was used for separating uranium from the eluate (0.5 N Na/sub 2/CO/sub 3/-0.5 N NaHCO/sub 3/) that was obtained in the extraction process of uranium from natural sea water by using the titanium-activated carbon composite adsorbent. Uranium in the eluate containing 3 mg/1 uranium was adsorbed by ion exchange resin (Amberlite IRA-400), and was eluted with the eluant (5 % NaCl-0.5 % Na/sub 2/CO/sub 3/). The concentration ratio of uranium in the final concentrated-eluate became more than 20 times. The eluting solution to the adsorbent and the eluant to the resin could be repeatedly used in the desorption-ion exchange process. Sodium carbonate was consumed at the desorption step, and sodium bicarbonate was consumed at the ion exchange step. The concentration ratio of uranium was found to decrease as chloride ion in the eluate increased.

Separation of uranium from sodium carbonate-sodium bicarbonate eluate by ion exchange method

Energy Technology Data Exchange (ETDEWEB)

Sakane, K.; Hirotsu, T.; Fujii, A.; Katoh, S.; Sugasaka, K. (Government Industrial Research. Inst., Shikoku, Takamatsu (Japan))

1982-01-01

The ion exchange method was used for separating uranium from the eluate (0.5 N Na/sub 2/CO/sub 3/-0.5 N NaHCO/sub 3/) that was obtained in the extraction process of uranium from natural sea water by using the titanium-activated carbon composite adsorbent. Uranium in the eluate containing 3 mg/l uranium was adsorbed by ion exchange resin (Amberlite IRA-400), and was eluted with the eluent (5% NaCl-0.5% Na/sub 2/CO/sub 3/). The concentration ratio of uranium in the final concentrated-eluate became more than 20 times. The eluting solution to the adsorbent and the eluant to the resin could be repeatedly used in the desorption-ion exchange process. Sodium carbonate was consumed at the desorption step, and sodium bicarbonate was consumed at the ion exchange step. The concentration ratio of uranium was found to decrease as chloride ion in the eluate increased.

Various methods to improve heat transfer in exchangers

Directory of Open Access Journals (Sweden)

Pavel Zitek

2015-01-01

Full Text Available The University of West Bohemia in Pilsen (Department of Power System Engineering is working on the selection of effective heat exchangers. Conventional shell and tube heat exchangers use simple segmental baffles. It can be replaced by helical baffles, which increase the heat transfer efficiency and reduce pressure losses. Their usage is demonstrated in the primary circuit of IV. generation MSR (Molten Salt Reactors. For high-temperature reactors we consider the use of compact desk heat exchangers, which are small, which allows the integral configuration of reactor. We design them from graphite composites, which allow up to 1000°C and are usable as exchangers: salt-salt or salt-acid (e.g. for the hydrogen production. In the paper there are shown thermo-physical properties of salts, material properties and principles of calculations.

METHOD FOR OPTIMAL RESOLUTION OF MULTI-AIRCRAFT CONFLICTS IN THREE-DIMENSIONAL SPACE

Directory of Open Access Journals (Sweden)

Denys Vasyliev

2017-03-01

Full Text Available Purpose: The risk of critical proximities of several aircraft and appearance of multi-aircraft conflicts increases under current conditions of high dynamics and density of air traffic. The actual problem is a development of methods for optimal multi-aircraft conflicts resolution that should provide the synthesis of conflict-free trajectories in three-dimensional space. Methods: The method for optimal resolution of multi-aircraft conflicts using heading, speed and altitude change maneuvers has been developed. Optimality criteria are flight regularity, flight economy and the complexity of maneuvering. Method provides the sequential synthesis of the Pareto-optimal set of combinations of conflict-free flight trajectories using multi-objective dynamic programming and selection of optimal combination using the convolution of optimality criteria. Within described method the following are defined: the procedure for determination of combinations of aircraft conflict-free states that define the combinations of Pareto-optimal trajectories; the limitations on discretization of conflict resolution process for ensuring the absence of unobservable separation violations. Results: The analysis of the proposed method is performed using computer simulation which results show that synthesized combination of conflict-free trajectories ensures the multi-aircraft conflict avoidance and complies with defined optimality criteria. Discussion: Proposed method can be used for development of new automated air traffic control systems, airborne collision avoidance systems, intelligent air traffic control simulators and for research activities.

High-resolution study of the Gamow-Teller strength distribution in the light nuclei 9B and 13N using the (3He,t) charge-exchange reaction at 420 MeV beam energy

International Nuclear Information System (INIS)

Scholl, Clemens

2010-01-01

Excited states in the light nuclei 9 B and 13 C were studied using the ( 3 He,t) charge-exchange reaction on 9 Be and 13 C targets. The measurements were performed at the research center for nuclear physics (RCNP) in Osaka, Japan, using the magnetic spectrometer Grand Raiden and the dispersive WS course. The 3 He beam with an energy of 420 MeV was accelerated by the RCNP Ring Cyclotron. The Grand Raiden spectrometer and the WS course allow to study the ( 3 He,t) charge-exchange reaction with an energy resolution of around 30 keV, which is one order of magnitude better than measurements with the (p,n) charge-exchange reaction. The high resolution allows to better separate individual states and to determine weak excitation strengths because of low background in the spectra. A total of 19 states in 13 N were studied, and a total of 20 states were observed in 9 B. Of these, 9 states in 13 C and 10 states in 9 B were identified as being excited by a Gamow-Teller transition. Charge-exchange reactions are related to beta-decay, and at zero momentum transfer a simple proportionality exists between the cross-section of the charge-exchange experiment and the Fermi (F) or Gamow-Teller (GT) beta-decay strength. While the Fermi strength B(F) is concentrated in the transition to the isobaric analog state, the Gamow-Teller strength B(GT) is scattered among the excited states. The main aim of the present study is to determine the B(GT) strengths in the nuclei 9 B and 13 N. The only charge-exchange study of 9 B was made 30 years ago with the (p,n) reaction and a resolution of around 300-400 keV. Many states, especially at high excitation energy, could not be resolved by that study. The present work was able to separate many weakly excited states with small decay width at high excitation energies (12-19 MeV) in 9 B and determine the B(GT) strength distribution by using recent high-precision beta-decay data. The results point to a strong difference in spatial structure between the

Inverse Problem and Variation Method to Optimize Cascade Heat Exchange Network in Central Heating System

Institute of Scientific and Technical Information of China (English)

ZHANG Yin; WEI Zhiyuan; ZHANG Yinping; WANG Xin

2017-01-01

Urban heating in northern China accounts for 40％ of total building energy usage.In central heating systems,heat is often transfened from heat source to users by the heat network where several heat exchangers arc installed at heat source,substations and terminals respectively.For given overall heating capacity and heat source temperarure,increasing the terminal fluid temperature is an effective way to improve the thermal performance of such cascade heat exchange network for energy saving.In this paper,the mathematical optimization model of the cascade heat exchange network with three-stage heat exchangers in series is established.Aim at maximizing the cold fluid temperature for given hot fluid temperature and overall heating capacity,the optimal heat exchange area distribution and the medium fluids' flow rates are determined through inverse problem and variation method.The preliminary results show that the heat exchange areas should be distributed equally for each heat exchanger.It also indicates that in order to improve the thernmal performance of the whole system,more heat exchange areas should be allocated to the heat exchanger where flow rate difference between two fluids is relatively small.This work is important for guiding the optimization design of practical cascade heating systems.

On absolute scaling in protein crystallography using sums of low-resolution intensities and Wilson statistics at low resolution

International Nuclear Information System (INIS)

Roth, M.

1986-01-01

A method of absolute scaling of diffraction data is proposed, based on the calculation of the sum of the intensity diffracted at low resolution (Bragg d spacing > 15 A). This sum is proportional to the mean-square deviation of the scattering-length density in the unit cell, and this property is used to determine the scale factor. The method is applied to the case of neutron diffraction using contrast variation experiments with biological molecules, and it is used to check the validity of some assumptions concerning the system under study, such as the global rate of H/D exchange or the uniformity of scattering-length density in the molecules. The use of this method requires an asymptotic correction of the sum of intensity. This correction is based on Porod's law, whose application to diffraction experiments is discussed, in particular for contrast variation experiments. An analysis of the spherical average of the diffracted intensity as a function of the scattering vector, compared to isotropic solution scattering, allows the conditions of applicability of Wilson statistics to be specified at low and medium resolution, i.e. the random statistical model underlying the Wilson statistics in this scattering range to be defined. (orig.)

Accessing High Spatial Resolution in Astronomy Using Interference Methods

Science.gov (United States)

Carbonel, Cyril; Grasset, Sébastien; Maysonnave, Jean

2018-01-01

In astronomy, methods such as direct imaging or interferometry-based techniques (Michelson stellar interferometry for example) are used for observations. A particular advantage of interferometry is that it permits greater spatial resolution compared to direct imaging with a single telescope, which is limited by diffraction owing to the aperture of…

Comparison of neuronal spike exchange methods on a Blue Gene/P supercomputer

Directory of Open Access Journals (Sweden)

Michael eHines

2011-11-01

Full Text Available The performance of several spike exchange methods using a Blue Gene/P supercomputerhas been tested with 8K to 128K cores using randomly connected networks of up to 32M cells with 1k connections per cell and 4M cells with 10k connections per cell. The spike exchange methods used are the standard Message Passing Interface collective, MPI_Allgather, and several variants of the non-blocking multisend method either implemented via non-blocking MPI_Isend, or exploiting the possibility of very low overhead direct memory access communication available on the Blue Gene/P. In all cases the worst performing method was that using MPI_Isend due to the high overhead of initiating a spike communication. The two best performing methods --- the persistent multisend method using the Record-Replay feature of the Deep Computing Messaging Framework DCMF_Multicast;and a two phase multisend in which a DCMF_Multicast is used to first send to a subset of phase 1 destination cores which then pass it on to their subset of phase 2 destination cores --- had similar performance with very low overhead for the initiation of spike communication. Departure from ideal scaling for the multisend methods is almost completely due to load imbalance caused by the largevariation in number of cells that fire on each processor in the interval between synchronization. Spike exchange time itself is negligible since transmission overlaps with computation and is handled by a direct memory access controller. We conclude that ideal performance scaling will be ultimately limited by imbalance between incoming processor spikes between synchronization intervals. Thus, counterintuitively, maximization of load balance requires that the distribution of cells on processors should not reflect neural net architecture but be randomly distributed so that sets of cells which are burst firing together should be on different processors with their targets on as large a set of processors as possible.

Thermodynamic optimization of ground heat exchangers with single U-tube by entropy generation minimization method

International Nuclear Information System (INIS)

Li Min; Lai, Alvin C.K.

2013-01-01

Highlights: ► A second-law-based analysis is performed for single U-tube ground heat exchangers. ► Two expressions for the optimal length and flow velocity are developed for GHEs. ► Empirical velocities of GHEs are large compared to thermodynamic optimum values. - Abstract: This paper investigates thermodynamic performance of borehole ground heat exchangers with a single U-tube by the entropy generation minimization method which requires information of heat transfer and fluid mechanics, in addition to thermodynamics analysis. This study first derives an expression for dimensionless entropy generation number, a function that consists of five dimensionless variables, including Reynolds number, dimensionless borehole length, scale factor of pressures, and two duty parameters of ground heat exchangers. The derivation combines a heat transfer model and a hydraulics model for borehole ground heat exchangers with the first law and the second law of thermodynamics. Next, the entropy generation number is minimized to produce two analytical expressions for the optimal length and the optimal flow velocity of ground heat exchangers. Then, this paper discusses and analyzes implications and applications of these optimization formulas with two case studies. An important finding from the case studies is that widely used empirical velocities of circulating fluid are too large to operate ground-coupled heat pump systems in a thermodynamic optimization way. This paper demonstrates that thermodynamic optimal parameters of ground heat exchangers can probably be determined by using the entropy generation minimization method.

Method of relative comparison of the thermohydraulic efficiency of heat exchange intensification in channels of heat-exchange surfaces

International Nuclear Information System (INIS)

Dubrovskij, E.V.; Vasil'ev, V.Ya.

2002-01-01

One introduces a technique to compare relatively thermohydraulic efficiency of heat transfer intensification in channels of heat exchange surfaces of any design types. It is shown that one should compare thermohydraulic efficiency of heat exchange intensification as to the thermal power of heat exchangers and pressure losses in channels with turbulators and in polished channels of heat exchange surfaces on the basis of dimensions of heat exchangers, their heat exchange surfaces and at similar (as to Re numbers) modes of coolant flow [ru

Understanding perovskite formation through the intramolecular exchange method in ambient conditions

Science.gov (United States)

Szostak, Rodrigo; Castro, Jhon A. P.; Marques, Adriano S.; Nogueira, Ana F.

2017-04-01

Among the methods to prepare hybrid organic-inorganic perovskite films, the intramolecular exchange method was the first one that made possible to prepare perovskite solar cells with efficiencies higher than 20%. However, perovskite formation by this method is not completely understood, especially in ambient conditions. In this work, perovskite films were prepared by the intramolecular exchange method in ambient conditions. The spin coating speed and the frequency of the MAI solution dripping onto PbI2(DMSO) were varied during the deposition steps. With the combination of these two parameters, a rigid control of the solvent drying was possible. Thus, depending on the chosen conditions, the intermediate MAPb3I8·2DMSO was formed with residual PbI2. Otherwise, direct formation of perovskite film was attained. A mechanism for the direct formation of bulk perovskite was proposed. We also investigated how the posterior thermal annealing affects the crystallinity and defects in perovskite films. With prolonged thermal annealing, the excess of MAI can be avoided, increasing the efficiency and decreasing the hysteresis of the solar cells. The best perovskite solar cell achieved a stabilized power output of 12.9%. The findings of this work pave the way for realizing the fabrication of efficient perovskite solar cells in ambient atmosphere, a very desirable condition for cost-efficient large scale manufacturing of this technology.

An Assessment of Transport Property Estimation Methods for Ammonia–Water Mixtures and Their Influence on Heat Exchanger Size

DEFF Research Database (Denmark)

Kærn, Martin Ryhl; Modi, Anish; Jensen, Jonas Kjær

2015-01-01

Transport properties of fluids are indispensable for heat exchanger design. The methods for estimating the transport properties of ammonia–water mixtures are not well established in the literature. The few existent methods are developed from none or limited, sometimes inconsistent experimental...... of ammonia–water mixtures. Firstly, the different methods are introduced and compared at various temperatures and pressures. Secondly, their individual influence on the required heat exchanger size (surface area) is investigated. For this purpose, two case studies related to the use of the Kalina cycle...... the interpolative methods in contrast to the corresponding state methods. Nevertheless, all possible mixture transport property combinations used herein resulted in a heat exchanger size within 4.3 % difference for the flue-gas heat recovery boiler, and within 12.3 % difference for the oil-based boiler....

Concepts and Methods of Conflict Resolution and Peace-Building ...

African Journals Online (AJOL)

The need for conflict resolution in our society is crucial. It is imperative because no two people perceive a particular thing exactly in the same way. Efforts to curb conflict and crisis-situations have often times been unsuccessful; occasioned not only by the complex nature of humanity, but also by the methods and means ...

Quantification of Iodine-123-FP-CIT SPECT with a resolution-independent method

International Nuclear Information System (INIS)

Dobbeleir, A.A.; Ham, H.R.; Hambye, A.E.; Vervaet, A.M.

2005-01-01

Accurate quantification of small-sized objects by SPECT is hampered by the partial volume effect. The present work evaluates the magnitude of this phenomenon with Iodine- 123 in phantom studies, and presents a resolution- independent method to quantify striatal I-123 FP-CIT uptake in patients. At first five syringes with internal diameters varying between 9 and 29mm and an anthropomorphic striatal phantom were filled with known concentrations of Iodine-123 and imaged by SPECT using different collimators and radii of rotation. Data were processed with and without scatter correction. From the measured activities, calibration factors were calculated for each specific collimator. Then a resolution-independent method for FP-CIT quantification using large regions of interest was developed and validated in 34 human studies (controls and patients) acquired in 2 different hospitals, by comparing its results to those obtained by a semi- quantitative striatal-to-occipital analysis. Taking the injected activity and decay into account, the measured counts/volume could be converted into absolute tracer concentrations. For the fan-beam, high resolution and medium energy collimators, the measured maximum activity in comparison to the 29 mm-diameter syringe was respectively 38%, 16% and 9% for the 9 mm-diameter syringe and 82%, 80% and 30% for the 16 mm syringe, and not significantly modified after scatter correction. For the anthropomorphic phantom, the error in measurement in % of the true concentration ranged between 0.3-9.5% and was collimator dependent. Medium energy collimators yielded the most homogeneous results. In the human studies, inter- observer variability was 11.4% for the striatal-to-occipital ratio and 3.1% for the resolution-independent method, with correlation coefficients >0.8 between both. The resolution- independent method was 89%-sensitive and 100%-specific to separate the patients without and with abnormal FP-CIT uptake (accuracy: 94%). Also the

A flexible spatiotemporal method for fusing satellite images with different resolutions

Science.gov (United States)

Xiaolin Zhu; Eileen H. Helmer; Feng Gao; Desheng Liu; Jin Chen; Michael A. Lefsky

2016-01-01

Studies of land surface dynamics in heterogeneous landscapes often require remote sensing datawith high acquisition frequency and high spatial resolution. However, no single sensor meets this requirement. This study presents a new spatiotemporal data fusion method, the Flexible Spatiotemporal DAta Fusion (FSDAF) method, to generate synthesized frequent high spatial...

Research on conflict resolution of collaborative design with fuzzy case-based reasoning method

Institute of Scientific and Technical Information of China (English)

HOU Jun-ming; SU Chong; LIANG Shuang; WANG Wan-shan

2009-01-01

Collaborative design is a new style for modern mechanical design to meet the requirement of increasing competition. Designers of different places complete the same work, but the conflict appears in the process of design which may interface the design. Case-based reasoning (CBR) method is applied to the problem of conflict resolution, which is in the artificial intelligence field. However, due to the uncertainties in knowledge representation, attribute description, and similarity measures of CBR, it is very difficult to find the similar cases from case database. A fuzzy CBR method was proposed to solve the problem of conflict resolution in collaborative design. The process of fuzzy CBR was introduced. Based on the feature attributes and their relative weights determined by a fuzzy technique, a fuzzy CBR retrieving mechanism was developed to retrieve conflict resolution cases that tend to enhance the functions of the database. By indexing, calculating the weight and defuzzicating of the cases, the case similarity can be obtained. Then the case consistency was measured to keep the right result. Finally, the fuzzy CBR method for conflict resolution was demonstrated by means of a case study. The prototype system based on web is developed to illustrate the methodology.

Study of the mass and energy resolution of the E parallel B charge exchange analyzer for TFTR

International Nuclear Information System (INIS)

Kaita, R.; Medley, S.S.

1979-09-01

The charge exchange diagnostic for TFTR requires simultaneous multispecie (H + , D + , γ + ) analysis of particles in the energy range of 0.5 - 150 keV. The analyzer design chosen to provide this capability employs a wide gap semi-circular region of superimposed parallel electric and magnetic fields to accomplish mass and energy resolution, respectively. Combined with a large area, multi-anode microchannel plate detector, this arrangement will enable the energy distributions of protons, deuterions, and tritons to be measured concurrently as a function of time during each discharge. A computer simulation program for calculating ion trajectories through the analyzer was written that includes a realistic model of the magnetic and electrostatic fringe fields. This report presents the results of a study of the proposed E parallel B analyzer, and it reveals that the fringe fields are not detrimental to the performance of the analyzer

Power-law behaviour evaluation from foreign exchange market data using a wavelet transform method

Science.gov (United States)

Wei, H. L.; Billings, S. A.

2009-09-01

Numerous studies in the literature have shown that the dynamics of many time series including observations in foreign exchange markets exhibit scaling behaviours. A simple new statistical approach, derived from the concept of the continuous wavelet transform correlation function (WTCF), is proposed for the evaluation of power-law properties from observed data. The new method reveals that foreign exchange rates obey power-laws and thus belong to the class of self-similarity processes.

Power-law behaviour evaluation from foreign exchange market data using a wavelet transform method

Energy Technology Data Exchange (ETDEWEB)

Wei, H.L., E-mail: w.hualiang@sheffield.ac.u [Department of Automatic Control and Systems Engineering, the University of Sheffield, Mappin Street, Sheffield, S1 3JD (United Kingdom); Billings, S.A., E-mail: s.billings@sheffield.ac.u [Department of Automatic Control and Systems Engineering, the University of Sheffield, Mappin Street, Sheffield, S1 3JD (United Kingdom)

2009-09-07

Numerous studies in the literature have shown that the dynamics of many time series including observations in foreign exchange markets exhibit scaling behaviours. A simple new statistical approach, derived from the concept of the continuous wavelet transform correlation function (WTCF), is proposed for the evaluation of power-law properties from observed data. The new method reveals that foreign exchange rates obey power-laws and thus belong to the class of self-similarity processes.

Power-law behaviour evaluation from foreign exchange market data using a wavelet transform method

International Nuclear Information System (INIS)

Wei, H.L.; Billings, S.A.

2009-01-01

Numerous studies in the literature have shown that the dynamics of many time series including observations in foreign exchange markets exhibit scaling behaviours. A simple new statistical approach, derived from the concept of the continuous wavelet transform correlation function (WTCF), is proposed for the evaluation of power-law properties from observed data. The new method reveals that foreign exchange rates obey power-laws and thus belong to the class of self-similarity processes.

A new graphical method for Pinch Analysis applications: Heat exchanger network retrofit and energy integration

International Nuclear Information System (INIS)

Gadalla, Mamdouh A.

2015-01-01

Energy integration is a key solution in chemical process and crude refining industries to minimise external fuel consumption and to face the impact of growing energy crises. Typical energy integration projects can reach a reduction of heating fuels and cold utilities by up to 40% compared with original designs or existing installations. Pinch Analysis is a leading tool and regarded as an efficient method to increase energy efficiency and minimise fuel flow consumptions. It is valid for both natures of design, grassroots and retrofit situations. It can practically be applied to synthesise a HEN (heat exchanger network) or modify an existing preheat train for minimum energy consumption. Heat recovery systems or HENs are networks for exchanging heat between hot and cold process sources. All heat transferred from hot process sources into cold process sinks represent the scope for energy integration. On the other hand, energies required beyond this integrated amount are to be satisfied by external utilities. Graphical representations of Pinch Analysis, such as Composite and Grand Composite Curves are very useful for grassroots designs. Nevertheless, in retrofit situation the analysis is not adequate and besides it is graphically tedious to represent existing exchangers on such graphs. This research proposes a new graphical method for the analysis of heat recovery systems, applicable to HEN retrofit. The new graphical method is based on plotting temperatures of process hot streams versus temperatures of process cold streams. A new graph is constructed for representing existing HENs. For a given network, each existing exchanger is represented by a straight line, whose slope is proportional to the ratio of heat capacities and flows. Further, the length of each exchanger line is related to the heat flow transferred across this exchanger. This new graphical representation can easily identify exchangers across the pinch, Network Pinch, pinching matches and improper placement

Protein hydrogen exchange measured at single-residue resolution by electron transfer dissociation mass spectrometry

DEFF Research Database (Denmark)

Rand, Kasper D; Zehl, Martin; Jensen, Ole Nørregaard

2009-01-01

Because of unparalleled sensitivity and tolerance to protein size, mass spectrometry (MS) has become a popular method for measuring the solution hydrogen (1H/2H) exchange (HX) of biologically relevant protein states. While incorporated deuterium can be localized to different regions by pepsin....... The deuterium labeling pattern of beta2-microglobulin is retained in the gaseous fragment ions by employing mild declustering conditions for electrospray ionization. A recently developed model peptide is used to arrive at such ion source declustering conditions that prevent the occurrence of intramolecular gas...

A study on development of a plugging margin evaluation method taking into account the fouling of shell-and tube heat exchangers

International Nuclear Information System (INIS)

Hwang, Kyeong Mo; Jin, Tae Eun; Kim, Kyung Hoon

2006-01-01

As the operating time of heat exchangers progresses, fouling caused by water-borne deposits and the number of plugged tubes increase and thermal performance decreases. Both fouling and tube plugging are known to interfere with normal flow characteristics and to reduce thermal efficiencies of heat exchangers. The heat exchangers of Korean nuclear power plants have been analyzed in terms of heat transfer rate and overall heat transfer coefficient as a means of heat exchanger management. Except for fouling resulting from the operation of heat exchangers, all the tubes of heat exchangers have been replaced when the number of plugged tubes exceeded the plugging criteria based on design performance sheet. This paper describes a plugging margin evaluation method taking into account the fouling of shell-and-tube heat exchangers. The method can evaluate thermal performance, estimate future fouling variation, and consider current fouling level in the calculation of plugging margin. To identify the effectiveness of the developed method, fouling and plugging margin evaluations were performed at a component cooling heat exchanger in a Korean nuclear power plant

Development of the system based code. v. 5. Method of margin exchange. pt. 2. Determination of quality assurance index based on a 'Vector Method'

International Nuclear Information System (INIS)

Asayama, Tai

2003-03-01

For the commercialization of fast breeder reactors, 'System Based Code', a completely new scheme of a code on structural integrity, is being developed. One of the distinguished features of the System Based Code is that it is able to determine a reasonable total margin on a structural of system, by allowing the exchanges of margins between various technical items. Detailed estimation of failure probability of a given combination of technical items and its comparison with a target value is one way to achieve this. However, simpler and easier methods that allow margin exchange without detailed calculation of failure probability are desirable in design. The authors have developed a simplified method such as a 'design factor method' from this viewpoint. This report describes a 'Vector Method', which was been newly developed. Following points are reported: 1) The Vector Method allows margin exchange evaluation on an 'equi-quality assurance plane' using vector calculation. Evaluation is easy and sufficient accuracy is achieved. The equi-quality assurance plane is obtained by a projection of an 'equi-failure probability surface in a n-dimensional space, which is calculated beforehand for typical combinations of design variables. 2) The Vector Method is considered to give the 'Quality Assurance Index Method' a probabilistic interpretation. 3) An algebraic method was proposed for the calculation of failure probabilities, which is necessary to obtain a equi-failure probability surface. This method calculates failure probabilities without using numerical methods such as Monte Carlo simulation or numerical integration. Under limited conditions, this method is quite effective compared to numerical methods. 4) An illustration of the procedure of margin exchange evaluation is given. It may be possible to use this method to optimize ISI plans; even it is not fully implemented in the System Based Code. (author)

Single-acquisition method for simultaneous determination of extrinsic gamma-camera sensitivity and spatial resolution

Energy Technology Data Exchange (ETDEWEB)

Santos, J.A.M. [Servico de Fisica Medica, Instituto Portugues de Oncologia Francisco Gentil do Porto, E.P.E., Rua Dr. Antonio Bernardino de Almeida, 4200-072 Porto (Portugal)], E-mail: a.miranda@portugalmail.pt; Sarmento, S. [Servico de Fisica Medica, Instituto Portugues de Oncologia Francisco Gentil do Porto, E.P.E., Rua Dr. Antonio Bernardino de Almeida, 4200-072 Porto (Portugal); Alves, P.; Torres, M.C. [Departamento de Fisica da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal); Bastos, A.L. [Servico de Medicina Nuclear, Instituto Portugues de Oncologia Francisco Gentil do Porto, E.P.E., Rua Dr. Antonio Bernardino de Almeida, 4200-072 Porto (Portugal); Ponte, F. [Servico de Fisica Medica, Instituto Portugues de Oncologia Francisco Gentil do Porto, E.P.E., Rua Dr. Antonio Bernardino de Almeida, 4200-072 Porto (Portugal)

2008-01-15

A new method for measuring simultaneously both the extrinsic sensitivity and spatial resolution of a gamma-camera in a single planar acquisition was implemented. A dual-purpose phantom (SR phantom; sensitivity/resolution) was developed, tested and the results compared with other conventional methods used for separate determination of these two important image quality parameters. The SR phantom yielded reproducible and accurate results, allowing an immediate visual inspection of the spatial resolution as well as the quantitative determination of the contrast for six different spatial frequencies. It also proved to be useful in the estimation of the modulation transfer function (MTF) of the image formation collimator/detector system at six different frequencies and can be used to estimate the spatial resolution as function of the direction relative to the digital matrix of the detector.

Single-acquisition method for simultaneous determination of extrinsic gamma-camera sensitivity and spatial resolution

International Nuclear Information System (INIS)

Santos, J.A.M.; Sarmento, S.; Alves, P.; Torres, M.C.; Bastos, A.L.; Ponte, F.

2008-01-01

A new method for measuring simultaneously both the extrinsic sensitivity and spatial resolution of a gamma-camera in a single planar acquisition was implemented. A dual-purpose phantom (SR phantom; sensitivity/resolution) was developed, tested and the results compared with other conventional methods used for separate determination of these two important image quality parameters. The SR phantom yielded reproducible and accurate results, allowing an immediate visual inspection of the spatial resolution as well as the quantitative determination of the contrast for six different spatial frequencies. It also proved to be useful in the estimation of the modulation transfer function (MTF) of the image formation collimator/detector system at six different frequencies and can be used to estimate the spatial resolution as function of the direction relative to the digital matrix of the detector

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

High-resolution method for evolving complex interface networks

Science.gov (United States)

Pan, Shucheng; Hu, Xiangyu Y.; Adams, Nikolaus A.

2018-04-01

In this paper we describe a high-resolution transport formulation of the regional level-set approach for an improved prediction of the evolution of complex interface networks. The novelty of this method is twofold: (i) construction of local level sets and reconstruction of a global level set, (ii) local transport of the interface network by employing high-order spatial discretization schemes for improved representation of complex topologies. Various numerical test cases of multi-region flow problems, including triple-point advection, single vortex flow, mean curvature flow, normal driven flow, dry foam dynamics and shock-bubble interaction show that the method is accurate and suitable for a wide range of complex interface-network evolutions. Its overall computational cost is comparable to the Semi-Lagrangian regional level-set method while the prediction accuracy is significantly improved. The approach thus offers a viable alternative to previous interface-network level-set method.

Optical methods to study the gas exchange processes in large diesel engines

Energy Technology Data Exchange (ETDEWEB)

Gros, S.; Hattar, C. [Wartsila Diesel International Oy, Vaasa (Finland); Hernberg, R.; Vattulainen, J. [Tampere Univ. of Technology, Tampere (Finland). Plasma Technology Lab.

1996-12-01

To be able to study the gas exchange processes in realistic conditions for a single cylinder of a large production-line-type diesel engine, a fast optical absorption spectroscopic method was developed. With this method line-of-sight UV-absorption of SO{sub 2} contained in the exhaust gas was measured as a function of time in the exhaust port area in a continuously fired medium speed diesel engine type Waertsilae 6L20. SO{sub 2} formed during the combustion from the fuel contained sulphur was used as a tracer to study the gas exchange as a function of time in the exhaust channel. In this case of a 4-stroke diesel engine by assuming a known concentration of SO{sub 2} in the exhaust gas after exhaust valve opening and before inlet and exhaust valve overlap period, the measured optical absorption was used to determine the gas density and further the instantaneous exhaust gas temperature during the exhaust cycle. (author)

Oversampling in the computed tomography measurements applied for bone structure studies as a method of spatial resolution improvement

International Nuclear Information System (INIS)

Tatoń, Grzegorz; Rokita, Eugeniusz; Rok, Tomasz; Beckmann, Felix

2012-01-01

Our purpose was to check the potential ability of oversampling as a method for computed tomography axial resolution improvement. The method of achieving isotropic and fine resolution, when the scanning system is characterized by anisotropic resolutions is proposed. In case of typical clinical system the axial resolution is much lower than the planar one. The idea relies on the scanning with a wide overlapping layers and subsequent resolution recovery on the level of scanning step. Simulated three-dimensional images, as well as the real microtomographic images of rat femoral bone were used in proposed solution tests. Original high resolution images were virtually scanned with a wide beam and a small step in order to simulate the real measurements. The low resolution image series were subsequently processed in order to back to the original fine one. Original, virtually scanned and recovered images resolutions were compared with the use of modulation transfer function (MTF). A good ability of oversampling as a method for the resolution recovery was showed. It was confirmed by comparing the resolving powers after and before resolution recovery. The MTF analysis showed resolution improvement. The resolution improvement was achieved but the image noise raised considerably, which is clearly visible on image histograms. Despite this disadvantage the proposed method can be successfully used in practice, especially in the trabecular bone studies because of high contrast between trabeculae and intertrabecular spaces

Heat exchanger performance monitoring guidelines

International Nuclear Information System (INIS)

Stambaugh, N.; Closser, W. Jr.; Mollerus, F.J.

1991-12-01

Fouling can occur in many heat exchanger applications in a way that impedes heat transfer and fluid flow and reduces the heat transfer or performance capability of the heat exchanger. Fouling may be significant for heat exchanger surfaces and flow paths in contact with plant service water. This report presents guidelines for performance monitoring of heat exchangers subject to fouling. Guidelines include selection of heat exchangers to monitor based on system function, safety function and system configuration. Five monitoring methods are discussed: the heat transfer, temperature monitoring, temperature effectiveness, delta P and periodic maintenance methods. Guidelines are included for selecting the appropriate monitoring methods and for implementing the selected methods. The report also includes a bibliography, example calculations, and technical notes applicable to the heat transfer method

A new cascade method for studying isotope effect in chemical exchange system without valance change

International Nuclear Information System (INIS)

Wen Xiaoning; Luo Wenzong

1987-01-01

A new cascade method for studying isotope effect in chemical exchange system without valance change is developed and described. This method is simple to use and consumes less extractant as compared with the commonly used Woodward method. It is also convenient for unstable systems

Method and system for dual resolution translation stage

Science.gov (United States)

Halpin, John Michael

2014-04-22

A dual resolution translation stage includes a stage assembly operable to receive an optical element and a low resolution adjustment device mechanically coupled to the stage assembly. The dual resolution stage also includes an adjustable pivot block mechanically coupled to the stage assembly. The adjustable pivot block includes a pivot shaft. The dual resolution stage further includes a lever arm mechanically coupled to the adjustable pivot block. The lever arm is operable to pivot about the pivot shaft. The dual resolution stage additionally includes a high resolution adjustment device mechanically coupled to the lever arm and the stage assembly.

Diluted melt proton exchange slab waveguides in LiNbO3: A new fabrication and characterization method

DEFF Research Database (Denmark)

Veng, Torben; Skettrup, Torben

1997-01-01

A method of dilute-melt proton exchange employing a mixture of glycerol and KHSO4 with lithium benzoate added is used to fabricate planar waveguides in c-cut LiNbO3. With this exchange melt system the waveguide refractive index profiles can be fabricated with a high degree of reproducibility...... the waveguide refractive index profile from the measured mode indices is introduced. The main advantage of this characterization method compared with other methods is that it also applies to single-mode waveguides. Using the new characterization method we investigate in detail the relation between waveguide...

Microchannel laminated mass exchanger and method of making

Science.gov (United States)

Martin, Peter M.; Bennett, Wendy D.; Matson, Dean W.; Stewart, Donald C.; Drost, Monte K.; Wegeng, Robert S.; Perez, Joseph M.; Feng, Xiangdong; Liu, Jun

2000-01-01

The present invention is a microchannel mass exchanger having a first plurality of inner thin sheets and a second plurality of outer thin sheets. The inner thin sheets each have a solid margin around a circumference, the solid margin defining a slot through the inner thin sheet thickness. The outer thin sheets each have at least two header holes on opposite ends and when sandwiching an inner thin sheet. The outer thin sheets further have a mass exchange medium. The assembly forms a closed flow channel assembly wherein fluid enters through one of the header holes into the slot and exits through another of the header holes after contacting the mass exchange medium.

CATION EXCHANGE METHOD FOR THE RECOVERY OF PROTACTINIUM

Science.gov (United States)

Studier, M.H.; Sullivan, J.C.

1959-07-14

A cation exchange prccess is described for separating protactinium values from thorium values whereby they are initially adsorbed together from an aqueous 0.1 to 2 N hydrochloric acid on a cation exchange resin in a column. Then selectively eluting the thorium by an ammonium sulfate solution and subsequently eluting the protactinium by an oxalate solution.

Efficient exact-exchange time-dependent density-functional theory methods and their relation to time-dependent Hartree-Fock.

Science.gov (United States)

Hesselmann, Andreas; Görling, Andreas

2011-01-21

A recently introduced time-dependent exact-exchange (TDEXX) method, i.e., a response method based on time-dependent density-functional theory that treats the frequency-dependent exchange kernel exactly, is reformulated. In the reformulated version of the TDEXX method electronic excitation energies can be calculated by solving a linear generalized eigenvalue problem while in the original version of the TDEXX method a laborious frequency iteration is required in the calculation of each excitation energy. The lowest eigenvalues of the new TDEXX eigenvalue equation corresponding to the lowest excitation energies can be efficiently obtained by, e.g., a version of the Davidson algorithm appropriate for generalized eigenvalue problems. Alternatively, with the help of a series expansion of the new TDEXX eigenvalue equation, standard eigensolvers for large regular eigenvalue problems, e.g., the standard Davidson algorithm, can be used to efficiently calculate the lowest excitation energies. With the help of the series expansion as well, the relation between the TDEXX method and time-dependent Hartree-Fock is analyzed. Several ways to take into account correlation in addition to the exact treatment of exchange in the TDEXX method are discussed, e.g., a scaling of the Kohn-Sham eigenvalues, the inclusion of (semi)local approximate correlation potentials, or hybrids of the exact-exchange kernel with kernels within the adiabatic local density approximation. The lowest lying excitations of the molecules ethylene, acetaldehyde, and pyridine are considered as examples.

An analytical method of estimating Value-at-Risk on the Belgrade Stock Exchange

Directory of Open Access Journals (Sweden)

Obadović Milica D.

2009-01-01

Full Text Available This paper presents market risk evaluation for a portfolio consisting of shares that are continuously traded on the Belgrade Stock Exchange, by applying the Value-at-Risk model - the analytical method. It describes the manner of analytical method application and compares the results obtained by implementing this method at different confidence levels. Method verification was carried out on the basis of the failure rate that demonstrated the confidence level for which this method was acceptable in view of the given conditions.

Difficult Sudoku Puzzles Created by Replica Exchange Monte Carlo Method

OpenAIRE

Watanabe, Hiroshi

2013-01-01

An algorithm to create difficult Sudoku puzzles is proposed. An Ising spin-glass like Hamiltonian describing difficulty of puzzles is defined, and difficult puzzles are created by minimizing the energy of the Hamiltonian. We adopt the replica exchange Monte Carlo method with simultaneous temperature adjustments to search lower energy states efficiently, and we succeed in creating a puzzle which is the world hardest ever created in our definition, to our best knowledge. (Added on Mar. 11, the ...

A novel method for enhancing the lateral resolution and image SNR in confocal microscopy

Science.gov (United States)

Chen, Youhua; Zhu, Dazhao; Fang, Yue; Kuang, Cuifang; Liu, Xu

2017-12-01

There is always a tradeoff between the resolution and the signal-to-noise ratio (SNR) in confocal microscopy. In particular, the pinhole size is very important for maintaining a balance between them. In this paper, we propose a method for improving the lateral resolution and image SNR in confocal microscopy without making any changes to the hardware. By using the fluorescence emission difference (FED) approach, we divide the images acquired by different pinhole sizes into one image acquired by the central pinhole and several images acquired by ring-shaped pinholes. Then, they are added together with the deconvolution method. Simulation and experimental results for fluorescent particles and cells show that our method can achieve a far better resolution than a large pinhole and a higher SNR than a small pinhole. Moreover, our method can improve the performance of classic confocal laser scanning microscopy (CLSM) to a certain extent, especially CLSM with a continuously variable pinhole.

Facile method to stain the bacterial cell surface for super-resolution fluorescence microscopy

Energy Technology Data Exchange (ETDEWEB)

Gunsolus, Ian L.; Hu, Dehong; Mihai, Cosmin; Lohse, Samuel E.; Lee, Chang-Soo; Torelli, Marco; Hamers, Robert J.; Murphy, Catherine; Orr, Galya; Haynes, Christy L.

2014-01-01

A method to fluorescently stain the surfaces of both Gram-negative and Gram-positive bacterial cells compatible with super-resolution fluorescence microscopy is presented. This method utilizes a commercially-available fluorescent probe to label primary amines at the surface of the cell. We demonstrate efficient staining of two bacterial strains, the Gram-negative Shewanella oneidensis MR-1 and the Gram-positive Bacillus subtilis 168. Using structured illumination microscopy and stochastic optical reconstruction microscopy, which require high quantum yield or specialized dyes, we show that this staining method may be used to resolve the bacterial cell surface with sub-diffraction-limited resolution. We further use this method to identify localization patterns of nanomaterials, specifically cadmium selenide quantum dots, following interaction with bacterial cells.

Laserspritzer: a simple method for optogenetic investigation with subcellular resolutions.

Directory of Open Access Journals (Sweden)

Qian-Quan Sun

Full Text Available To build a detailed circuit diagram in the brain, one needs to measure functional synaptic connections between specific types of neurons. A high-resolution circuit diagram should provide detailed information at subcellular levels such as soma, distal and basal dendrites. However, a limitation lies in the difficulty of studying long-range connections between brain areas separated by millimeters. Brain slice preparations have been widely used to help understand circuit wiring within specific brain regions. The challenge exists because long-range connections are likely to be cut in a brain slice. The optogenetic approach overcomes these limitations, as channelrhodopsin 2 (ChR2 is efficiently transported to axon terminals that can be stimulated in brain slices. Here, we developed a novel fiber optic based simple method of optogenetic stimulation: the laserspritzer approach. This method facilitates the study of both long-range and local circuits within brain slice preparations. This is a convenient and low cost approach that can be easily integrated with a slice electrophysiology setup, and repeatedly used upon initial validation. Our data with direct ChR2 mediated-current recordings demonstrates that the spatial resolution of the laserspritzer is correlated with the size of the laserspritzer, and the resolution lies within the 30 µm range for the 5 micrometer laserspritzer. Using olfactory cortical slices, we demonstrated that the laserspritzer approach can be applied to selectively activate monosynaptic perisomatic GABAergic basket synapses, or long-range intracortical glutamatergic inputs formed on different subcellular domains within the same cell (e.g. distal and proximal dendrites. We discuss significant advantages of the laserspritzer approach over the widely used collimated LED whole-field illumination method in brain slice electrophysiological research.

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.)

High-resolution X-ray crystal structure of bovine H-protein using the high-pressure cryocooling method.

Science.gov (United States)

Higashiura, Akifumi; Ohta, Kazunori; Masaki, Mika; Sato, Masaru; Inaka, Koji; Tanaka, Hiroaki; Nakagawa, Atsushi

2013-11-01

Recently, many technical improvements in macromolecular X-ray crystallography have increased the number of structures deposited in the Protein Data Bank and improved the resolution limit of protein structures. Almost all high-resolution structures have been determined using a synchrotron radiation source in conjunction with cryocooling techniques, which are required in order to minimize radiation damage. However, optimization of cryoprotectant conditions is a time-consuming and difficult step. To overcome this problem, the high-pressure cryocooling method was developed (Kim et al., 2005) and successfully applied to many protein-structure analyses. In this report, using the high-pressure cryocooling method, the X-ray crystal structure of bovine H-protein was determined at 0.86 Å resolution. Structural comparisons between high- and ambient-pressure cryocooled crystals at ultra-high resolution illustrate the versatility of this technique. This is the first ultra-high-resolution X-ray structure obtained using the high-pressure cryocooling method.

Estimation of Global 1km-grid Terrestrial Carbon Exchange Part II: Evaluations and Applications

Science.gov (United States)

Murakami, K.; Sasai, T.; Kato, S.; Niwa, Y.; Saito, M.; Takagi, H.; Matsunaga, T.; Hiraki, K.; Maksyutov, S. S.; Yokota, T.

2015-12-01

Global terrestrial carbon cycle largely depends on a spatial pattern in land cover type, which is heterogeneously-distributed over regional and global scales. Many studies have been trying to reveal distribution of carbon exchanges between terrestrial ecosystems and atmosphere for understanding global carbon cycle dynamics by using terrestrial biosphere models, satellite data, inventory data, and so on. However, most studies remained within several tens of kilometers grid spatial resolution, and the results have not been enough to understand the detailed pattern of carbon exchanges based on ecological community and to evaluate the carbon stocks by forest ecosystems in each countries. Improving the sophistication of spatial resolution is obviously necessary to enhance the accuracy of carbon exchanges. Moreover, the improvement may contribute to global warming awareness, policy makers and other social activities. We show global terrestrial carbon exchanges (net ecosystem production, net primary production, and gross primary production) with 1km-grid resolution. The methodology for these estimations are shown in the 2015 AGU FM poster "Estimation of Global 1km-grid Terrestrial Carbon Exchange Part I: Developing Inputs and Modelling". In this study, we evaluated the carbon exchanges in various regions with other approaches. We used the satellite-driven biosphere model (BEAMS) as our estimations, GOSAT L4A CO2 flux data, NEP retrieved by NICAM and CarbonTracer2013 flux data, for period from Jun 2001 to Dec 2012. The temporal patterns for this period were indicated similar trends between BEAMS, GOSAT, NICAM, and CT2013 in many sub-continental regions. Then, we estimated the terrestrial carbon exchanges in each countries, and could indicated the temporal patterns of the exchanges in large carbon stock regions.Global terrestrial carbon cycle largely depends on a spatial pattern of land cover type, which is heterogeneously-distributed over regional and global scales. Many

Plasma stream transport method (2) Use of charge exchange plasma source

International Nuclear Information System (INIS)

Tsuchimoto, T.

1978-01-01

The plasma stream transport method using a single plasma source has limitations for practical film deposition. Using a charge exchange phenomenon, a new plasma source is devised and tested by the plasma stream transport machine. Metals, silicon dioxide, and nitride films are deposited by this system. The mechanism of deposition under relatively high vacuum surrounding a silicon wafer is discussed as is the effect of radical atoms

Entropy resistance minimization: An alternative method for heat exchanger analyses

International Nuclear Information System (INIS)

Cheng, XueTao

2013-01-01

In this paper, the concept of entropy resistance is proposed based on the entropy generation analyses of heat transfer processes. It is shown that smaller entropy resistance leads to larger heat transfer rate with fixed thermodynamic force difference and smaller thermodynamic force difference with fixed heat transfer rate, respectively. For the discussed two-stream heat exchangers in which the heat transfer rates are not given and the three-stream heat exchanger with prescribed heat capacity flow rates and inlet temperatures of the streams, smaller entropy resistance leads to larger heat transfer rate. For the two-stream heat exchangers with fixed heat transfer rate, smaller entropy resistance leads to larger effectiveness. Furthermore, it is shown that smaller values of the concepts of entropy generation numbers and modified entropy generation number do not always correspond to better performance of the discussed heat exchangers. - Highlights: • The concept of entropy resistance is defined for heat exchangers. • The concepts based on entropy generation are used to analyze heat exchangers. • Smaller entropy resistance leads to better performance of heat exchangers. • The applicability of entropy generation minimization is conditional

The computational optimization of heat exchange efficiency in stack chimneys

Energy Technology Data Exchange (ETDEWEB)

Van Goch, T.A.J.

2012-02-15

stack chimney heat exchanger is used for heating or cooling applications, what is the expected performance and how do the design parameters relate to this performance'. Simulation models were developed in the BPS tool ESP-r. The most important design parameters and their relative influence on the performance indicators were analysed based on sensitivity analysis (SA). From this analysis general design guidelines were derived ('optimal set of design parameters'). A multi objective optimization of the design parameters was performed on the simulation models, using the responsive surface methods and artificial neural network capabilities of optimization environment ModEContier to speed up the iteration process. In this optimization, 'heat exchange in stack chimneys is optimized annually'. The uncertainty in the optimized results has been analysed using uncertainty analysis (UA). Finally, the appropriateness of deploying a complex, high resolution simulation has been evaluated by studying current modelling resolution selection methodology found in literature.

Resolution improvement of ultrasonic echography methods in non destructive testing by adaptative deconvolution

International Nuclear Information System (INIS)

Vivet, L.

1989-01-01

The ultrasonic echography has a lot of advantages which make it attractive for nondestructive testing. But the important acoustic energy useful to go through very attenuating materials can be got only with resonant translators, that is a limit for the resolution on measured echograms. This resolution can be improved by deconvolution. But this method is a problem for austenitic steel. Here is developed a method of time deconvolution which allows to take in account the characteristics of the wave. A first step of phase correction and a second step of spectral equalization which gives back the spectral contents of ideal reflectivity. The two steps use fast Kalman filters which reduce the cost of the method

Cross-tropopause Transport In Tropopause Folds: Mechanisms and Sensitivity To Model Resolution

Science.gov (United States)

Gray, S. L.

The rate and processes of transfer of mass and chemical species between the strato- sphere and troposphere (stratosphere-troposphere exchange) are currently uncertain. In the midlatitudes exchange appears to be dominated by processes associated with tropopause folds and cut-off lows. The development of a tropopause fold is a reversible process and thus irreversible processes must occur for the permanent transfer of ma- terial across the tropopause boundary. Proposed processes include turbulent mixing, quasi-isentropic mixing, convectively breaking gravity waves, deep convection and radiative heating. Numerical models run at typical climate or regional-scale resolutions are unable to re- solve the fine-scale features observed in tropopause folds. It is hypothesised that both the rate of exchange and its partitioning into different processes, as derived from nu- merical model simulations, are sensitive to model resolution. This hypothesis is tested through simulations of a tropopause folding event associated with a vigorous surface cold front which tracked across the British Isles. Climate to high-mesoscale resolution simulations incorporating passive tracers are performed using the mesoscale version of the Met Office Unified Model. The mechanism by which the parametrized convec- tion leads to exchange is the subject of further examination.

Super-resolution biomolecular crystallography with low-resolution data.

Science.gov (United States)

Schröder, Gunnar F; Levitt, Michael; Brunger, Axel T

2010-04-22

X-ray diffraction plays a pivotal role in the understanding of biological systems by revealing atomic structures of proteins, nucleic acids and their complexes, with much recent interest in very large assemblies like the ribosome. As crystals of such large assemblies often diffract weakly (resolution worse than 4 A), we need methods that work at such low resolution. In macromolecular assemblies, some of the components may be known at high resolution, whereas others are unknown: current refinement methods fail as they require a high-resolution starting structure for the entire complex. Determining the structure of such complexes, which are often of key biological importance, should be possible in principle as the number of independent diffraction intensities at a resolution better than 5 A generally exceeds the number of degrees of freedom. Here we introduce a method that adds specific information from known homologous structures but allows global and local deformations of these homology models. Our approach uses the observation that local protein structure tends to be conserved as sequence and function evolve. Cross-validation with R(free) (the free R-factor) determines the optimum deformation and influence of the homology model. For test cases at 3.5-5 A resolution with known structures at high resolution, our method gives significant improvements over conventional refinement in the model as monitored by coordinate accuracy, the definition of secondary structure and the quality of electron density maps. For re-refinements of a representative set of 19 low-resolution crystal structures from the Protein Data Bank, we find similar improvements. Thus, a structure derived from low-resolution diffraction data can have quality similar to a high-resolution structure. Our method is applicable to the study of weakly diffracting crystals using X-ray micro-diffraction as well as data from new X-ray light sources. Use of homology information is not restricted to X

Improvement to heat exchanger elements, to the corresponding exchangers and their methods of production

International Nuclear Information System (INIS)

1974-01-01

A description is given of a flat rectangular element for a heat exchanger made by closely assembling two regular ribbed sheets against each other. In the element thus obtained the ribbing forms two parallel passages at two opposite sides of the rectangle and running along these two sides, and a series of identical channels parallel to the two other sides of the rectangle. The two ends of these channels respectively give on to the two passages. Each light-alloy sheet is very thin, under .5mm. The total thickness of the element is less than 5 mm. The total area of each rectangular side of the element is around one square metre, its length being greater than 1 metre. The heat exchanger is built up of a bank of these elements juxtaposed side by side with requisite interpositions for the circulation of the external exchange [fr

Estimation of Global 1km-grid Terrestrial Carbon Exchange Part I: Developing Inputs and Modelling

Science.gov (United States)

Sasai, T.; Murakami, K.; Kato, S.; Matsunaga, T.; Saigusa, N.; Hiraki, K.

2015-12-01

Global terrestrial carbon cycle largely depends on a spatial pattern in land cover type, which is heterogeneously-distributed over regional and global scales. However, most studies, which aimed at the estimation of carbon exchanges between ecosystem and atmosphere, remained within several tens of kilometers grid spatial resolution, and the results have not been enough to understand the detailed pattern of carbon exchanges based on ecological community. Improving the sophistication of spatial resolution is obviously necessary to enhance the accuracy of carbon exchanges. Moreover, the improvement may contribute to global warming awareness, policy makers and other social activities. In this study, we show global terrestrial carbon exchanges (net ecosystem production, net primary production, and gross primary production) with 1km-grid resolution. As methodology for computing the exchanges, we 1) developed a global 1km-grid climate and satellite dataset based on the approach in Setoyama and Sasai (2013); 2) used the satellite-driven biosphere model (Biosphere model integrating Eco-physiological And Mechanistic approaches using Satellite data: BEAMS) (Sasai et al., 2005, 2007, 2011); 3) simulated the carbon exchanges by using the new dataset and BEAMS by the use of a supercomputer that includes 1280 CPU and 320 GPGPU cores (GOSAT RCF of NIES). As a result, we could develop a global uniform system for realistically estimating terrestrial carbon exchange, and evaluate net ecosystem production in each community level; leading to obtain highly detailed understanding of terrestrial carbon exchanges.

The potential of high resolution ultrasonic in-situ methods

International Nuclear Information System (INIS)

Schuster, K.

2010-01-01

Document available in extended abstract form only. In the framework of geomechanical assessment of final repository underground openings the knowledge of geophysical rock parameters are of importance. Ultrasonic methods proved to be good geophysical tools to provide appropriate high resolution parameters for the characterisation of rock. In this context the detection and characterisation of rock heterogeneities at different scales, including the Excavation Damaged/disturbed Zone (EDZ/EdZ) features, play an important role. Especially, kinematic and dynamic parameters derived from ultrasonic measurements can be linked very close to rock mechanic investigations and interpretations. BGR uses high resolution ultrasonic methods, starting with emitted frequencies of about 1 kHz (seismic) and going up to about 100 kHz. The method development is going on and appropriate research and investigations are performed since many years at different European radioactive waste disposal related underground research laboratories in different potential host rocks. The most frequented are: Mont Terri Rock Laboratory, Switzerland (Opalinus Clay, OPA), Underground Research Laboratory Meuse/Haute- Marne, France (Callovo-Oxfordian, COX), Underground Research Facility Mol, Belgium (Boom Clay, BC), Aespoe Hard Rock Laboratory, Sweden (granites), Rock Laboratory Grimsel, Switzerland (granites) and Asse salt mine, Germany (rock salt). The methods can be grouped into borehole based methods and noninvasive methods like refraction and reflection methods, which are performed in general from the drift wall. Additionally, as a combination of these both methods a sort of vertical seismic profiling (VSP) is applied. The best qualified method, or a combination of methods, have to be chosen according to the scientific questions and the local site conditions. The degree of spatial resolution of zones of interest or any kind of anomaly depends strongly on the distance of these objects to the ultrasonic

High resolution and high sensitivity methods for oligosaccharide mapping and characterization by normal phase high performance liquid chromatography following derivatization with highly fluorescent anthranilic acid.

Science.gov (United States)

Anumula, K R; Dhume, S T

1998-07-01

Facile labeling of oligosaccharides (acidic and neutral) in a nonselective manner was achieved with highly fluorescent anthranilic acid (AA, 2-aminobenzoic acid) (more than twice the intensity of 2-aminobenzamide, AB) for specific detection at very high sensitivity. Quantitative labeling in acetate-borate buffered methanol (approximately pH 5.0) at 80 degreesC for 60 min resulted in negligible or no desialylation of the oligosaccharides. A high resolution high performance liquid chromatographic method was developed for quantitative oligosaccharide mapping on a polymeric-NH2bonded (Astec) column operating under normal phase and anion exchange (NP-HPAEC) conditions. For isolation of oligosaccharides from the map by simple evaporation, the chromatographic conditions developed use volatile acetic acid-triethylamine buffer (approximately pH 4.0) systems. The mapping and characterization technology was developed using well characterized standard glycoproteins. The fluorescent oligosaccharide maps were similar to the maps obtained by the high pH anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD), except that the fluorescent maps contained more defined peaks. In the map, the oligosaccharides separated into groups based on charge, size, linkage, and overall structure in a manner similar to HPAEC-PAD with contribution of -COOH function from the label, anthranilic acid. However, selectivity of the column for sialic acid linkages was different. A second dimension normal phase HPLC (NP-HPLC) method was developed on an amide column (TSK Gel amide-80) for separation of the AA labeled neutral complex type and isomeric structures of high mannose type oligosaccharides. The oligosaccharides labeled with AA are compatible with biochemical and biophysical techniques, and use of matrix assisted laser desorption mass spectrometry for rapid determination of oligosaccharide mass map of glycoproteins is demonstrated. High resolution of NP-HPAEC and NP-HPLC methods

Layered double hydroxides as the next generation inorganic anion exchangers: Synthetic methods versus applicability.

Science.gov (United States)

Chubar, Natalia; Gilmour, Robert; Gerda, Vasyl; Mičušík, Matej; Omastova, Maria; Heister, Katja; Man, Pascal; Fraissard, Jacques; Zaitsev, Vladimir

2017-07-01

This work is the first report that critically reviews the properties of layered double hydroxides (LDHs) on the level of speciation in the context of water treatment application and dynamic adsorption conditions, as well as the first report to associate these properties with the synthetic methods used for LDH preparation. Increasingly stronger maximum allowable concentrations (MAC) of various contaminants in drinking water and liquid foodstuffs require regular upgrades of purification technologies, which might also be useful in the extraction of valuable substances for reuse in accordance with modern sustainability strategies. Adsorption is the main separation technology that allows the selective extraction of target substances from multicomponent solutions. Inorganic anion exchangers arrived in the water business relatively recently to achieve the newly approved standards for arsenic levels in drinking water. LDHs (or hydrotalcites, HTs) are theoretically the best anion exchangers due to their potential to host anions in their interlayer space, which increases their anion removal capacity considerably. This potential of the interlayer space to host additional amounts of target aqueous anions makes the LDHs superior to bulk anion exchanger. The other unique advantage of these layered materials is the flexibility of the chemical composition of the metal oxide-based layers and the interlayer anions. However, until now, this group of "classical" anion exchangers has not found its industrial application in adsorption and catalysis at the industrial scale. To accelerate application of LDHs in water treatment on the industrial scale, the authors critically reviewed recent scientific and technological knowledge on the properties and adsorptive removal of LDHs from water on the fundamental science level. This also includes review of the research tools useful to reveal the adsorption mechanism and the material properties beyond the nanoscale. Further, these properties are

A method for geological hazard extraction using high-resolution remote sensing

International Nuclear Information System (INIS)

Wang, Q J; Chen, Y; Bi, J T; Lin, Q Z; Li, M X

2014-01-01

Taking Yingxiu, the epicentre of the Wenchuan earthquake, as the study area, a method for geological disaster extraction using high-resolution remote sensing imagery was proposed in this study. A high-resolution Digital Elevation Model (DEM) was used to create mask imagery to remove interfering factors such as buildings and water at low altitudes. Then, the mask imagery was diced into several small parts to reduce the large images' inconsistency, and they were used as the sources to be classified. After that, vector conversion was done on the classified imagery in ArcGIS. Finally, to ensure accuracy, other interfering factors such as buildings at high altitudes, bare land, and land covered by little vegetation were removed manually. Because the method can extract geological hazards in a short time, it is of great importance for decision-makers and rescuers who need to know the degree of damage in the disaster area, especially within 72 hours after an earthquake. Therefore, the method will play an important role in decision making, rescue, and disaster response planning

Experimental Characterization and Modelization of Ion Exchange Kinetics for a Carboxylic Resin in Infinite Solution Volume Conditions. Application to Monovalent-Trivalent Cations Exchange

Energy Technology Data Exchange (ETDEWEB)

Picart, S.; Mokhtari, H.; Jobelin, I. [CEA Marcoule, Nucl Energy Div, RadioChem and Proc Dept, Actinides Chem and Convers Lab, F-30207 Bagnols Sur Ceze (France); Ramiere, I. [Fuel Simulat Lab, Fuel Study Dept, F-13108 St Paul Les Durance (France)

2010-07-01

This study is devoted to the characterization of ion exchange inside a microsphere of carboxylic resin. It aims at describing the kinetics of this exchange reaction which is known to be controlled by interdiffusion in the particle. The fractional attainment of equilibrium function of time depends on the concentration of the cations in the resin which can be modelled by the Nernst-Planck equation. A powerful approach for the numerical resolution of this equation is introduced in this paper. This modeling is based on the work of Helfferich but involves an implicit numerical scheme which reduces the computational cost. Knowing the diffusion coefficients of the cations in the resin and the radius of the spherical exchanger, the kinetics can be hence completely determined. When those diffusion parameters are missing, they can be deduced by fitting experimental data of fractional attainment of equilibrium. An efficient optimization tool coupled with the implicit resolution has been developed for this purpose. A monovalent/trivalent cation exchange had been experimentally characterized for a carboxylic resin. Diffusion coefficients and concentration profiles in the resin were then deduced through this new model. (authors)

Experimental Characterization and Modelization of Ion Exchange Kinetics for a Carboxylic Resin in Infinite Solution Volume Conditions. Application to Monovalent-Trivalent Cations Exchange

International Nuclear Information System (INIS)

Picart, S.; Mokhtari, H.; Jobelin, I.; Ramiere, I.

2010-01-01

This study is devoted to the characterization of ion exchange inside a microsphere of carboxylic resin. It aims at describing the kinetics of this exchange reaction which is known to be controlled by interdiffusion in the particle. The fractional attainment of equilibrium function of time depends on the concentration of the cations in the resin which can be modelled by the Nernst-Planck equation. A powerful approach for the numerical resolution of this equation is introduced in this paper. This modeling is based on the work of Helfferich but involves an implicit numerical scheme which reduces the computational cost. Knowing the diffusion coefficients of the cations in the resin and the radius of the spherical exchanger, the kinetics can be hence completely determined. When those diffusion parameters are missing, they can be deduced by fitting experimental data of fractional attainment of equilibrium. An efficient optimization tool coupled with the implicit resolution has been developed for this purpose. A monovalent/trivalent cation exchange had been experimentally characterized for a carboxylic resin. Diffusion coefficients and concentration profiles in the resin were then deduced through this new model. (authors)

Resolution improvement and noise reduction in human pinhole SPECT using a multi-ray approach and the SHINE method

International Nuclear Information System (INIS)

Seret, A.; Vanhove, C.; Defrise, M.

2009-01-01

Purpose: This work aimed at quantifying the gains in spatial resolution and noise that could be achieved when using resolution modelling based on a multi-ray approach and additionally the Statistical and Heuristic Noise Extraction (SHINE) method in human pinhole single photon emission tomography (PH-SPECT). Methods: PH-SPECT of two line phantoms and one homogeneous cylinder were recorded using parameters suited for studies of the human neck area. They were reconstructed using pinhole dedicated ordered subsets expectation maximisation algorithm including a resolution recovery technique based on 7 or 21 rays. Optionally, the SPECT data were SHINE pre-processed. Transverse and axial full widths at half-maximum (FWHM) were obtained from the line phantoms. The noise was quantified using the coefficient of variation (COV) derived from the uniform phantom. Two human PH-SPECT studies of the thyroid (a hot nodule and a very low uptake) were processed with the same algorithms. Results: Depending on the number of iterations, FWHM decreased by 30 to 50% when using the multi-ray approach in the reconstruction process. The SHINE method did not affect the resolution but decreased the COV by at least 20% and by 45% when combined with the multi-ray method. The two human studies illustrated the gain in spatial resolution and the decrease in noise afforded both by the multi-ray reconstruction and the SHINE method. Conclusion: Iterative reconstruction with resolution modelling allows to obtain high resolution human PH-SPECT studies with reduced noise content. The SHINE method affords an additional noise reduction without compromising the resolution. (orig.)

A Method of Heat Exchange Structure Optimization of the Cricoid Plastic Parts

Directory of Open Access Journals (Sweden)

Dongpo Yang

2014-01-01

Full Text Available This paper research on the effect of heat transfer performance of ring wall structure change of ship water heater top cricoid hood. A method of equivalent conversion is applied on simplify the structure of finned tube heat exchanger, it distinct reduce the computational grid, and improve the simulation speed and accuracy. This method can be used to calculate the ventilation and heat transfer of that compact configuration type structure in the complex component. Changing the ring wall structure can improve heat transfer performance, based on the method of equivalent transformation, a new heat transfer structure is established.

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

The long-run dynamic relationship between exchange rate and its attention index: Based on DCCA and TOP method

Science.gov (United States)

Wang, Xuan; Guo, Kun; Lu, Xiaolin

2016-07-01

The behavior information of financial market plays a more and more important role in modern economic system. The behavior information reflected in INTERNET search data has already been used in short-term prediction for exchange rate, stock market return, house price and so on. However, the long-run relationship between behavior information and financial market fluctuation has not been studied systematically. Further, most traditional statistic methods and econometric models could not catch the dynamic and non-linear relationship. An attention index of CNY/USD exchange rate is constructed based on search data from 360 search engine of China in this paper. Then the DCCA and Thermal Optimal Path methods are used to explore the long-run dynamic relationship between CNY/USD exchange rate and the corresponding attention index. The results show that the significant interdependency exists and the change of exchange rate is 1-2 days lag behind the attention index.

Resolution of the neutron transport equation by a three-dimensional least square method

International Nuclear Information System (INIS)

Varin, Elisabeth

2001-01-01

The knowledge of space and time distribution of neutrons with a certain energy or speed allows the exploitation and control of a nuclear reactor and the assessment of the irradiation dose about an irradiated nuclear fuel storage site. The neutron density is described by a transport equation. The objective of this research thesis is to develop a software for the resolution of this stationary equation in a three-dimensional Cartesian domain by means of a deterministic method. After a presentation of the transport equation, the author gives an overview of the different deterministic resolution approaches, identifies their benefits and drawbacks, and discusses the choice of the Ressel method. The least square method is precisely described and then applied. Numerical benchmarks are reported for validation purposes

Axial flow heat exchanger devices and methods for heat transfer using axial flow devices

Science.gov (United States)

Koplow, Jeffrey P.

2016-02-16

Systems and methods described herein are directed to rotary heat exchangers configured to transfer heat to a heat transfer medium flowing in substantially axial direction within the heat exchangers. Exemplary heat exchangers include a heat conducting structure which is configured to be in thermal contact with a thermal load or a thermal sink, and a heat transfer structure rotatably coupled to the heat conducting structure to form a gap region between the heat conducting structure and the heat transfer structure, the heat transfer structure being configured to rotate during operation of the device. In example devices heat may be transferred across the gap region from a heated axial flow of the heat transfer medium to a cool stationary heat conducting structure, or from a heated stationary conducting structure to a cool axial flow of the heat transfer medium.

Kerr microscopy study of exchange-coupled FePt/Fe exchange spring magnets

Energy Technology Data Exchange (ETDEWEB)

Hussain, Zaineb; Kumar, Dileep [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452001 (India); Reddy, V. Raghavendra, E-mail: varimalla@yahoo.com [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452001 (India); Gupta, Ajay [Amity Center for Spintronic Materials, Amity University, Noida 201303 (India)

2017-05-15

Magnetization reversal and magnetic microstructure of top soft magnetic layer (Fe) in exchange spring coupled L1{sub 0} FePt/Fe is studied using high resolution Kerr microscopy. With remnant state of the hard magnetic layer (L1{sub 0} FePt) as initial condition, magnetization loops along with magnetic domains are recorded for the top soft magnetic layer (Fe) using Kerr microscopy. Considerable shifting of Fe layer hysteresis loop from center which is similar to exchange bias phenomena is observed. It is also observed that one can tune the magnitude of hysteresis shift by reaching the remanent state from different saturating fields (H{sub SAT}) and also by varying the angle between measuring field and H{sub SAT}. The hysteresis loops and magnetic domains of top soft Fe layer demonstrate unambiguously that soft magnetic layer at remanent state in such exchange coupled system is having unidirectional anisotropy. An analogy is drawn and the observations are explained in terms of established model of exchange bias phenomena framed for field-cooled ferromagnetic - antiferromagnetic bilayer systems. - Highlights: • Kerr microscopy of top soft magnetic Fe layer in exchange spring coupled L1{sub 0} FePt (30 nm)/Fe (22 nm) is reported. • Considerable shifting of Fe layer hysteresis loop from center which is similar to exchange bias phenomena is observed. • Tuneable nature of magnitude of hysteresis shift is shown. • It is unambiguously shown that the top soft Fe magnetic layer at remanent state is having unidirectional anisotropy.

Water exchange method for colonoscopy: learning curve of an experienced colonoscopist in a U.S. community practice setting.

Science.gov (United States)

Fischer, Leonard S; Lumsden, Antoinette; Leung, Felix W

2012-07-01

Water exchange colonoscopy has been reported to reduce examination discomfort and to provide salvage cleansing in unsedated or minimally sedated patients. The prolonged insertion time and perceived difficulty of insertion associated with water exchange have been cited as a barrier to its widespread use. To assess the feasibility of learning and using the water exchange method of colonoscopy in a U.S. community practice setting. Quality improvement program in nonacademic community endoscopy centers. Patients undergoing sedated diagnostic, surveillance, or screening colonoscopy. After direct coaching by a knowledgeable trainer, an experienced colonoscopist initiated colonoscopy using the water method. Whenever >5 min elapsed without advancing the colonoscope, conversion to air insufflation was made to ensure timely completion of the examination. Water Method Intention-to-treat (ITT) cecal intubation rate (CIR). Female patients had a significantly higher rate of past abdominal surgery and a significantly lower ITTCIR. The ITTCIR showed a progressive increase over time in both males and females to 85-90%. Mean insertion time was maintained at 9 to 10 min. The overall CIR was 99%. Use of water exchange did not preclude cecal intubation upon conversion to usual air insufflation in sedated patients examined by an experienced colonoscopist. With practice ITTCIR increased over time in both male and female patients. Larger volumes of water exchanged were associated with higher ITTCIR and better quality scores of bowel preparation. The data suggest that learning water exchange by a busy colonoscopist in a community practice setting is feasible and outcomes conform to accepted quality standards.

Separation of thorium from cerium by the ion-exchange sorption method. Pt. 3

International Nuclear Information System (INIS)

Sozanski, A.

1981-01-01

The method is described of separation of trace-quantities of thorium from chloride and ceric sulfate solutions. Thorium is sorbed selectively on the ion exchanger chelating Vofatite MC-50. Thorium-free ceric solutions were achieved and after ionite eluation concentrates of oxides were considerably enriched. (author)

A novel approach for multiple mobile objects path planning: Parametrization method and conflict resolution strategy

International Nuclear Information System (INIS)

Ma, Yong; Wang, Hongwei; Zamirian, M.

2012-01-01

We present a new approach containing two steps to determine conflict-free paths for mobile objects in two and three dimensions with moving obstacles. Firstly, the shortest path of each object is set as goal function which is subject to collision-avoidance criterion, path smoothness, and velocity and acceleration constraints. This problem is formulated as calculus of variation problem (CVP). Using parametrization method, CVP is converted to time-varying nonlinear programming problems (TNLPP) and then resolved. Secondly, move sequence of object is assigned by priority scheme; conflicts are resolved by multilevel conflict resolution strategy. Approach efficiency is confirmed by numerical examples. -- Highlights: ► Approach with parametrization method and conflict resolution strategy is proposed. ► Approach fits for multi-object paths planning in two and three dimensions. ► Single object path planning and multi-object conflict resolution are orderly used. ► Path of each object obtained with parameterization method in the first phase. ► Conflict-free paths gained by multi-object conflict resolution in the second phase.

Topology of foreign exchange markets using hierarchical structure methods

Science.gov (United States)

Naylor, Michael J.; Rose, Lawrence C.; Moyle, Brendan J.

2007-08-01

This paper uses two physics derived hierarchical techniques, a minimal spanning tree and an ultrametric hierarchical tree, to extract a topological influence map for major currencies from the ultrametric distance matrix for 1995-2001. We find that these two techniques generate a defined and robust scale free network with meaningful taxonomy. The topology is shown to be robust with respect to method, to time horizon and is stable during market crises. This topology, appropriately used, gives a useful guide to determining the underlying economic or regional causal relationships for individual currencies and to understanding the dynamics of exchange rate price determination as part of a complex network.

preparation of beryllia n concentrate from beryllium minerals by ion exchange method

International Nuclear Information System (INIS)

Shoukry, M.M.; Atrees, M. Sh.; Hashem, M.D.

2007-01-01

The present work is concerned with the preparation of pure Beryllia concentrate from Zabara beryl mineralization in the mica schist of Wadi El Gemal area in the eastern desert. This has been possible through application of ion exchange techniques to selectively concentrate. This method is based on the fact that the beryllium complex of ethylene diamine tetra acetic acid (EDTA) at a ph of about 3.5, is much weaker than the corresponding complexes of iron and aluminum. It was, therefore, possible to effect a complete separation of beryllium from the latter on a cation exchange resin, the studied optimum conditions of separation include a contact time of 3 minute and ph of 3.5 for the selective separation of beryllium from its EDTA solution after a prior separation of alum

Charge-constrained auxiliary-density-matrix methods for the Hartree–Fock exchange contribution

DEFF Research Database (Denmark)

Merlot, Patrick; Izsak, Robert; Borgoo, Alex

2014-01-01

Three new variants of the auxiliary-density-matrix method (ADMM) of Guidon, Hutter, and VandeVondele [J. Chem. Theory Comput. 6, 2348 (2010)] are presented with the common feature thatthey have a simplified constraint compared with the full orthonormality requirement of the earlier ADMM1 method. ....... All ADMM variants are tested for accuracy and performance in all-electron B3LYP calculations with several commonly used basis sets. The effect of the choice of the exchange functional for the ADMM exchange–correction term is also investigated....

Nuclear magnetic resonance line-shape analysis and determination of exchange rates

International Nuclear Information System (INIS)

Rao, B.D.

1989-01-01

The fact that chemical exchange processes occur at rates that cover a broad range and produce readily detectable effects on the spectrum is one of the attractive features of high-resolution NMR. The description of these line shapes in the presence of spin-spin coupling requires the density matrix theory which is rather complex. Analysis of the line shapes usually needs computer simulations and is capable of providing reliable information on the exchange rates as well as spectral parameters in the absence of exchange. Simplified procedures, ignoring spin-spin coupling, often result in deviations in these exchange and spectral parameters determined. A step-by-step procedure is detailed in this chapter for setting up the matrices required for computing the line shapes of exchanges involving weakly coupled spin systems on the basis of the density matrix theory without the need for a detailed understanding of the theory. A knowledge of the energy level structure and allowed transitions in the NMR spectra of the individual weakly coupled spin systems is all that is required. The procedure is amenable to numerical computation. The group of illustrative examples chosen to demonstrate the development of the computational tools cover some of the commonly encountered cases of exchange from simple systems to rather complex ones. Such exchanges occur frequently in biological molecules, especially those involving enzyme-substrate complexes. In cases where the experimental line shapes are obtained with respectable precision, and the relevant exchange processes are unambiguously identifiable, the computer simulation method of line-shape analysis is capable of providing useful and incisive information. The example of the 31P exchanges in the adenylate kinase is illustrative of this point

Relabeling exchange method (REM) for learning in neural networks

Science.gov (United States)

Wu, Wen; Mammone, Richard J.

1994-02-01

The supervised training of neural networks require the use of output labels which are usually arbitrarily assigned. In this paper it is shown that there is a significant difference in the rms error of learning when `optimal' label assignment schemes are used. We have investigated two efficient random search algorithms to solve the relabeling problem: the simulated annealing and the genetic algorithm. However, we found them to be computationally expensive. Therefore we shall introduce a new heuristic algorithm called the Relabeling Exchange Method (REM) which is computationally more attractive and produces optimal performance. REM has been used to organize the optimal structure for multi-layered perceptrons and neural tree networks. The method is a general one and can be implemented as a modification to standard training algorithms. The motivation of the new relabeling strategy is based on the present interpretation of dyslexia as an encoding problem.

High-resolution study of the Gamow-Teller strength distribution in the light nuclei {sup 9}B and {sup 13}N using the ({sup 3}He,t) charge-exchange reaction at 420 MeV beam energy

Energy Technology Data Exchange (ETDEWEB)

Scholl, Clemens

2010-07-07

Excited states in the light nuclei {sup 9}B and {sup 13}C were studied using the ({sup 3}He,t) charge-exchange reaction on {sup 9}Be and {sup 13}C targets. The measurements were performed at the research center for nuclear physics (RCNP) in Osaka, Japan, using the magnetic spectrometer Grand Raiden and the dispersive WS course. The {sup 3}He beam with an energy of 420 MeV was accelerated by the RCNP Ring Cyclotron. The Grand Raiden spectrometer and the WS course allow to study the ({sup 3}He,t) charge-exchange reaction with an energy resolution of around 30 keV, which is one order of magnitude better than measurements with the (p,n) charge-exchange reaction. The high resolution allows to better separate individual states and to determine weak excitation strengths because of low background in the spectra. A total of 19 states in {sup 13}N were studied, and a total of 20 states were observed in {sup 9}B. Of these, 9 states in {sup 13}C and 10 states in {sup 9}B were identified as being excited by a Gamow-Teller transition. Charge-exchange reactions are related to beta-decay, and at zero momentum transfer a simple proportionality exists between the cross-section of the charge-exchange experiment and the Fermi (F) or Gamow-Teller (GT) beta-decay strength. While the Fermi strength B(F) is concentrated in the transition to the isobaric analog state, the Gamow-Teller strength B(GT) is scattered among the excited states. The main aim of the present study is to determine the B(GT) strengths in the nuclei {sup 9}B and {sup 13}N. The only charge-exchange study of {sup 9}B was made 30 years ago with the (p,n) reaction and a resolution of around 300-400 keV. Many states, especially at high excitation energy, could not be resolved by that study. The present work was able to separate many weakly excited states with small decay width at high excitation energies (12-19 MeV) in {sup 9}B and determine the B(GT) strength distribution by using recent high-precision beta-decay data. The

A Kalman Filter-Based Method to Generate Continuous Time Series of Medium-Resolution NDVI Images

Directory of Open Access Journals (Sweden)

Fernando Sedano

2014-12-01

Full Text Available A data assimilation method to produce complete temporal sequences of synthetic medium-resolution images is presented. The method implements a Kalman filter recursive algorithm that integrates medium and moderate resolution imagery. To demonstrate the approach, time series of 30-m spatial resolution NDVI images at 16-day time steps were generated using Landsat NDVI images and MODIS NDVI products at four sites with different ecosystems and land cover-land use dynamics. The results show that the time series of synthetic NDVI images captured seasonal land surface dynamics and maintained the spatial structure of the landscape at higher spatial resolution. The time series of synthetic medium-resolution NDVI images were validated within a Monte Carlo simulation framework. Normalized residuals decreased as the number of available observations increased, ranging from 0.2 to below 0.1. Residuals were also significantly lower for time series of synthetic NDVI images generated at combined recursion (smoothing than individually at forward and backward recursions (filtering. Conversely, the uncertainties of the synthetic images also decreased when the number of available observations increased and combined recursions were implemented.

Electronic properties of antiferromagnetic UBi2 metal by exact exchange for correlated electrons method

Directory of Open Access Journals (Sweden)

E Ghasemikhah

2012-03-01

Full Text Available This study investigated the electronic properties of antiferromagnetic UBi2 metal by using ab initio calculations based on the density functional theory (DFT, employing the augmented plane waves plus local orbital method. We used the exact exchange for correlated electrons (EECE method to calculate the exchange-correlation energy under a variety of hybrid functionals. Electric field gradients (EFGs at the uranium site in UBi2 compound were calculated and compared with the experiment. The EFGs were predicted experimentally at the U site to be very small in this compound. The EFG calculated by the EECE functional are in agreement with the experiment. The densities of states (DOSs show that 5f U orbital is hybrided with the other orbitals. The plotted Fermi surfaces show that there are two kinds of charges on Fermi surface of this compound.

A method of undifferenced ambiguity resolution for GPS+GLONASS precise point positioning.

Science.gov (United States)

Yi, Wenting; Song, Weiwei; Lou, Yidong; Shi, Chuang; Yao, Yibin

2016-05-25

Integer ambiguity resolution is critical for achieving positions of high precision and for shortening the convergence time of precise point positioning (PPP). However, GLONASS adopts the signal processing technology of frequency division multiple access and results in inter-frequency code biases (IFCBs), which are currently difficult to correct. This bias makes the methods proposed for GPS ambiguity fixing unsuitable for GLONASS. To realize undifferenced GLONASS ambiguity fixing, we propose an undifferenced ambiguity resolution method for GPS+GLONASS PPP, which considers the IFCBs estimation. The experimental result demonstrates that the success rate of GLONASS ambiguity fixing can reach 75% through the proposed method. Compared with the ambiguity float solutions, the positioning accuracies of ambiguity-fixed solutions of GLONASS-only PPP are increased by 12.2%, 20.9%, and 10.3%, and that of the GPS+GLONASS PPP by 13.0%, 35.2%, and 14.1% in the North, East and Up directions, respectively.

Study of electron-molecule collision via finite-element method and r-matrix propagation technique: Exact exchange

International Nuclear Information System (INIS)

Abdolsalami, F.; Abdolsalami, M.; Perez, L.; Gomez, P.

1995-01-01

The authors have applied the finite-element method to electron-molecule collision with the exchange effect implemented rigorously. All the calculations are done in the body-frame within the fixed-nuclei approximation, where the exact treatment of exchange as a nonlocal effect results in a set of coupled integro-differential equations. The method is applied to e-H 2 and e-N 2 scatterings and the cross sections obtained are in very good agreement with the corresponding results the authors have generated from the linear-algebraic approach. This confirms the significant difference observed between their results generated by linear-algebraic method and the previously published e-N 2 cross sections. Their studies show that the finite-element method is clearly superior to the linear-algebraic approach in both memory usage and CPU time especially for large systems such as e-N 2 . The system coefficient matrix obtained from the finite-element method is often sparse and smaller in size by a factor of 12 to 16, compared to the linear-algebraic technique. Moreover, the CPU time required to obtain stable results with the finite-element method is significantly smaller than the linear-algebraic approach for one incident electron energy. The usage of computer resources in the finite-element method can even be reduced much further when (1) scattering calculations involving multiple electron energies are performed in one computer run and (2) exchange, which is a short range effect, is approximated by a sparse matrix. 17 refs., 7 figs., 5 tabs

Functional Dynamics of Hexameric Helicase Probed by Hydrogen Exchange and Simulation

Science.gov (United States)

Radou, Gaël; Dreyer, Frauke N.; Tuma, Roman; Paci, Emanuele

2014-01-01

The biological function of large macromolecular assemblies depends on their structure and their dynamics over a broad range of timescales; for this reason, it is a significant challenge to investigate these assemblies using conventional experimental techniques. One of the most promising experimental techniques is hydrogen-deuterium exchange detected by mass spectrometry. Here, we describe to our knowledge a new computational method for quantitative interpretation of deuterium exchange kinetics and apply it to a hexameric viral helicase P4 that unwinds and translocates RNA into a virus capsid at the expense of ATP hydrolysis. Room-temperature dynamics probed by a hundred nanoseconds of all-atom molecular dynamics simulations is sufficient to predict the exchange kinetics of most sequence fragments and provide a residue-level interpretation of the low-resolution experimental results. The strategy presented here is also a valuable tool to validate experimental data, e.g., assignments, and to probe mechanisms that cannot be observed by x-ray crystallography, or that occur over timescales longer than those that can be realistically simulated, such as the opening of the hexameric ring. PMID:25140434

Ion exchange currents in vacuum accelerator tubes

International Nuclear Information System (INIS)

Eastham, D.A.; Thorn, R.

1978-01-01

Ion exchange currents (microdischarges) have been observed in short lengths of accelerator tube. The occurrence of these discharges can be related to the trajectories of ions in the tube. High-resolution mass spectra of the negative and positive ion components have been obtained. (author)

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...

Workshop on high-resolution, large-acceptance spectrometers

Energy Technology Data Exchange (ETDEWEB)

Zeidman, B. (ed.)

1981-01-01

The purpose of the Workshop on High-Resolution, Large-Acceptance Spectrometers was to provide a means for exchange of information among those actively engaged in the design and construction of these new spectrometers. Thirty-seven papers were prepared for the data base.

The log mean heat transfer rate method of heat exchanger considering the influence of heat radiation

International Nuclear Information System (INIS)

Wong, K.-L.; Ke, M.-T.; Ku, S.-S.

2009-01-01

The log mean temperature difference (LMTD) method is conventionally used to calculate the total heat transfer rate of heat exchangers. Because the heat radiation equation contains the 4th order exponential of temperature which is very complicate in calculations, thus LMTD method neglects the influence of heat radiation. From the recent investigation of a circular duct in some practical situations, it is found that even in the situation of the temperature difference between outer duct surface and surrounding is low to 1 deg. C, the heat radiation effect can not be ignored in the situations of lower ambient convective heat coefficient and greater surface emissivities. In this investigation, the log mean heat transfer rate (LMHTR) method which considering the influence of heat radiation, is developed to calculate the total heat transfer rate of heat exchangers.

Provincial Water Resource Allocation in Agricultural Sector Using Conflict Resolution Methods in Atrak Basin

Directory of Open Access Journals (Sweden)

Parvaneh KazemiMeresht

2017-03-01

Full Text Available Introduction: In spite of improving the water productivity due to development in water infrastructure systems, population increasing causing the water withdrawal is triple in the last fifty years. In this situation competition on water consumption especially in the agricultural sector which is the biggest consumer in the world and also in Iran is a severe problem. Water allocation has been assessed widely in the recent past. Additionally, several studies have explored methods to incorporate conflict resolution methods in water allocation. In a general classification, there are two types of methods. One is the method based on game theory, graph theory and general models based oncooperative game into a category that has the ability to consider the stakeholder preferences and assess the several scenarios under specified policy. Although this type of methods iseligible to cooperate the stakeholder in modeling but due to their weakness on considering the information on details and their limitations in adoption with changes caused from uncertainty, they are not popular in practical cases. Another type of conflict resolution method which is eligible to considering more detailed information of systems has the optimization approach basically, has the most interests between researchers. There is namely the Nash bargaining solution, the Kalai-Smorodinesky solution, the Equal loss solution and the area monotonic solution. There are several studies which areapplied these methods to investigate about groundwater (5, 6 and10. There are a few applications of water resource allocation models which is incorporated with conflict resolution methods in Transboundary Rivers nowadays and restricted to game theory related methods (1 and 2. The aim of this study is the assessment of the application of conflict resolution methods such as symmetric and non symmetric Nash solution, non symmetricKalai-Smorodinesky, non symmetric equal loss solution and finally the area

Method for removing cesium from aqueous liquid, method for purifying the reactor coolant in boiling water and pressurized water reactors and a mixed ion exchanged resin bed, useful in said purification

International Nuclear Information System (INIS)

Otte, J.N.A.; Liebmann, D.

1989-01-01

The invention relates to a method for removing cesium from an aqueous liquid, and to a resin bed containing a mixture of an anion exchange resin and cation exchange resin useful in said purification. In a preferred embodiment, the present invention is a method for purifying the reactor coolant of a presurized water or boiling water reactor. Said method, which is particularly advantageously employed in purifying the reactor coolant in the primary circuit of a pressurized reactor, comprises contacting at least a portion of the reactor coolant with a strong base anion exchange resin and the strong acid cation exchange resin derived from a highly cross-linked, macroporous copolymer of a monovinylidene aromatic and a cross-linking monomer copolymerizable therewith. Although the reactor coolant can sequentially be contacted with one resin type and thereafter with the second resin type, the contact is preferably conducted using a resin bed comprising a mixture of the cation and anion exchange resins. 1 fig., refs

An artificial neural network ensemble method for fault diagnosis of proton exchange membrane fuel cell system

International Nuclear Information System (INIS)

Shao, Meng; Zhu, Xin-Jian; Cao, Hong-Fei; Shen, Hai-Feng

2014-01-01

The commercial viability of PEMFC (proton exchange membrane fuel cell) systems depends on using effective fault diagnosis technologies in PEMFC systems. However, many researchers have experimentally studied PEMFC (proton exchange membrane fuel cell) systems without considering certain fault conditions. In this paper, an ANN (artificial neural network) ensemble method is presented that improves the stability and reliability of the PEMFC systems. In the first part, a transient model giving it flexibility in application to some exceptional conditions is built. The PEMFC dynamic model is built and simulated using MATLAB. In the second, using this model and experiments, the mechanisms of four different faults in PEMFC systems are analyzed in detail. Third, the ANN ensemble for the fault diagnosis is built and modeled. This model is trained and tested by the data. The test result shows that, compared with the previous method for fault diagnosis of PEMFC systems, the proposed fault diagnosis method has higher diagnostic rate and generalization ability. Moreover, the partial structure of this method can be altered easily, along with the change of the PEMFC systems. In general, this method for diagnosis of PEMFC has value for certain applications. - Highlights: • We analyze the principles and mechanisms of the four faults in PEMFC (proton exchange membrane fuel cell) system. • We design and model an ANN (artificial neural network) ensemble method for the fault diagnosis of PEMFC system. • This method has high diagnostic rate and strong generalization ability

Delineation of wetland areas from high resolution WorldView-2 data by object-based method

International Nuclear Information System (INIS)

Hassan, N; Hamid, J R A; Adnan, N A; Jaafar, M

2014-01-01

Various classification methods are available that can be used to delineate land cover types. Object-based is one of such methods for delineating the land cover from satellite imageries. This paper focuses on the digital image processing aspects of discriminating wetland areas via object-based method using high resolution satellite multispectral WorldView-2 image data taken over part of Penang Island region. This research is an attempt to improve the wetland area delineation in conjunction with a range of classification techniques which can be applied to satellite data with high spatial and spectral resolution such as World View 2. The intent is to determine a suitable approach to delineate and map these wetland areas more appropriately. There are common parameters to take into account that are pivotal in object-based method which are the spatial resolution and the range of spectral channels of the imaging sensor system. The preliminary results of the study showed object-based analysis is capable of delineating wetland region of interest with an accuracy that is acceptable to the required tolerance for land cover classification

Inclusion of exact exchange in the noniterative partial-differential-equation method of electron-molecule scattering - Application to e-N2

Science.gov (United States)

Weatherford, C. A.; Onda, K.; Temkin, A.

1985-01-01

The noniterative partial-differential-equation (PDE) approach to electron-molecule scattering of Onda and Temkin (1983) is modified to account for the effects of exchange explicitly. The exchange equation is reduced to a set of inhomogeneous equations containing no integral terms and solved noniteratively in a difference form; a method for propagating the solution to large values of r is described; the changes in the polarization potential of the original PDE method required by the inclusion of exact static exchange are indicated; and the results of computations for e-N2 scattering in the fixed-nuclei approximation are presented in tables and graphs and compared with previous calculations and experimental data. Better agreement is obtained using the modified PDE method.

An Automated Anion-Exchange Method forthe Selective Sorption of five Groups ofTrace Elements in Neutron-IrradiatedBiological Material

International Nuclear Information System (INIS)

Samsahl, K.

1966-02-01

An anion-exchange method based on fast selective sorption steps from mixtures of sulfuric, hydrobromic, and hydrochloric acid solutions has been developed for the separation of five different groups of radioactive trace elements in neutron-irradiated biological material. The separations are performed automatically with a simple proportioning pump apparatus. The apparatus allows the exact adjustment of influent solutions to the series of ion-exchange columns. The practical application of the method is described in detail. The successful use of the method is practically independent on the level of Na activity present in the sample

Multi-GPU Accelerated Admittance Method for High-Resolution Human Exposure Evaluation.

Science.gov (United States)

Xiong, Zubiao; Feng, Shi; Kautz, Richard; Chandra, Sandeep; Altunyurt, Nevin; Chen, Ji

2015-12-01

A multi-graphics processing unit (GPU) accelerated admittance method solver is presented for solving the induced electric field in high-resolution anatomical models of human body when exposed to external low-frequency magnetic fields. In the solver, the anatomical model is discretized as a three-dimensional network of admittances. The conjugate orthogonal conjugate gradient (COCG) iterative algorithm is employed to take advantage of the symmetric property of the complex-valued linear system of equations. Compared against the widely used biconjugate gradient stabilized method, the COCG algorithm can reduce the solving time by 3.5 times and reduce the storage requirement by about 40%. The iterative algorithm is then accelerated further by using multiple NVIDIA GPUs. The computations and data transfers between GPUs are overlapped in time by using asynchronous concurrent execution design. The communication overhead is well hidden so that the acceleration is nearly linear with the number of GPU cards. Numerical examples show that our GPU implementation running on four NVIDIA Tesla K20c cards can reach 90 times faster than the CPU implementation running on eight CPU cores (two Intel Xeon E5-2603 processors). The implemented solver is able to solve large dimensional problems efficiently. A whole adult body discretized in 1-mm resolution can be solved in just several minutes. The high efficiency achieved makes it practical to investigate human exposure involving a large number of cases with a high resolution that meets the requirements of international dosimetry guidelines.

Heat exchangers and methods of construction thereof

International Nuclear Information System (INIS)

Schluderberg, D.C.

1988-01-01

A heat exchanger is described comprising a shell having first inlet means and first outlet means for the flow of a first fluid therethrough, a plurality of tubes within the shell to provide a path for flow of a second fluid in heat exchange relation to the first fluid, second inlet means and second outlet means for flow of the second fluid to and from the tubes respectively, a tubular member concentric with at least a portion of the length of one of the tubes to define a space between the tube and the tubular member, at least one radially outwardly projecting portion on the tubular member, and a plurality of tube support means spaced apart and disposed generally perpendicular to the tube axes, wherein the tubular member is fixedly attached at one end to one of the tube support means and at the other end to an adjacent one of the tube support means, the space between the tube and the tubular member is closed to flow of both the first fluid and the second fluid, and the radially outwardly projecting portion on the tubular member extends longitudinally to allow flexing of the tubular member and expanding thereof radially outwardly during construction of the heat exchanger so as to allow insertion of the tube into the tubular member, the radially outwardly projecting portion defining a gap which contributes to the space between the tube and the tubular member. 6 figs

Resolution of RNA using high-performance liquid chromatography

NARCIS (Netherlands)

Mclaughlin, L.W.; Bischoff, Rainer

1987-01-01

High-performance liquid chromatographic techniques can be very effective for the resolution and isolation of nucleic acids. The characteristic ionic (phosphodiesters) and hydrophobic (nucleobases) properties of RNAs can be exploited for their separation. In this respect anion-exchange and

A high-resolution method for the localization of proanthocyanidins in plant tissues

Directory of Open Access Journals (Sweden)

Panter Stephen

2011-05-01

Full Text Available Abstract Background Histochemical staining of plant tissues with 4-dimethylaminocinnamaldehyde (DMACA or vanillin-HCl is widely used to characterize spatial patterns of proanthocyanidin accumulation in plant tissues. These methods are limited in their ability to allow high-resolution imaging of proanthocyanidin deposits. Results Tissue embedding techniques were used in combination with DMACA staining to analyze the accumulation of proanthocyanidins in Lotus corniculatus (L. and Trifolium repens (L. tissues. Embedding of plant tissues in LR White or paraffin matrices, with or without DMACA staining, preserved the physical integrity of the plant tissues, allowing high-resolution imaging that facilitated cell-specific localization of proanthocyanidins. A brown coloration was seen in proanthocyanidin-producing cells when plant tissues were embedded without DMACA staining and this was likely to have been due to non-enzymatic oxidation of proanthocyanidins and the formation of colored semiquinones and quinones. Conclusions This paper presents a simple, high-resolution method for analysis of proanthocyanidin accumulation in organs, tissues and cells of two plant species with different patterns of proanthocyanidin accumulation, namely Lotus corniculatus (birdsfoot trefoil and Trifolium repens (white clover. This technique was used to characterize cell type-specific patterns of proanthocyanidin accumulation in white clover flowers at different stages of development.

Multi-scale method for the resolution of the neutronic kinetics equations

International Nuclear Information System (INIS)

Chauvet, St.

2008-10-01

In this PhD thesis and in order to improve the time/precision ratio of the numerical simulation calculations, we investigate multi-scale techniques for the resolution of the reactor kinetics equations. We choose to focus on the mixed dual diffusion approximation and the quasi-static methods. We introduce a space dependency for the amplitude function which only depends on the time variable in the standard quasi-static context. With this new factorization, we develop two mixed dual problems which can be solved with Cea's solver MINOS. An algorithm is implemented, performing the resolution of these problems defined on different scales (for time and space). We name this approach: the Local Quasi-Static method. We present here this new multi-scale approach and its implementation. The inherent details of amplitude and shape treatments are discussed and justified. Results and performances, compared to MINOS, are studied. They illustrate the improvement on the time/precision ratio for kinetics calculations. Furthermore, we open some new possibilities to parallelize computations with MINOS. For the future, we also introduce some improvement tracks with adaptive scales. (author)

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.)

Combination of the method of basic precipitation of lanthanons with the ion exchange distribution method by means of ammonium acetate

International Nuclear Information System (INIS)

Hubicki, W.; Hubicka, H.

1980-01-01

The method of basic precipitation of lanthanons was combined with the ion exchange distribution method using ammonium acetate. As a result of chromatogram development 1:2 the good results of distribution of Sm -Nd, the fractions 99,9% Nd 2 O 3 and Pr 6 O 11 and 99,5% La 2 O 3 were obtained. It was found that the way of packing the column influenced greatly the efficiency of ion distribution. (author)

Impacts of tropospheric ozone and climate change on net primary productivity and net carbon exchange of China’s forest ecosystems

Science.gov (United States)

Wei Ren; Hanqin Tian; Bo Tao; Art Chappelka; Ge Sun; et al

2011-01-01

Aim We investigated how ozone pollution and climate change/variability have interactively affected net primary productivity (NPP) and net carbon exchange (NCE) across China’s forest ecosystem in the past half century. Location Continental China. Methods Using the dynamic land ecosystem model (DLEM) in conjunction with 10-km-resolution gridded historical data sets (...

Experimental study to optimize time resolution and detection limit of online 222Rn-in-water measurements

International Nuclear Information System (INIS)

Just, G.; Freyer, K.; Treutler, H.C.; Philipsborn, H. von

2001-01-01

The possibility to detect short-term variations of the activity concentration of 222 Rn in water by online monitoring with temporal resolutions of a few minutes and a lower limit of detection of about 1 Bq/l enhances the applicability of such measurements. New applications would be possible in the field of hydro-geology in which Rn is used as tracer gas, the monitoring of pumping procedures, for the study of exchange processes during groundwater sampling and for various applications with geophysical effects. A suitable, simple method is the measuring principle proposed by Surbeck (Fribourg) some years ago which is based on the separation of air and water by a diffusion membrane. Process parameters enhancing the time resolution of the method as well as the efficiency of different radon detectors have been studied. (orig.) [de

Dissociative charge exchange of H2+

International Nuclear Information System (INIS)

Bruijn, D. de.

1983-01-01

This thesis is devoted to molecular dissociation, in particular the dissociation of the hydrogen molecule H 2 arising from electron capture of its ion H 2 + in a collision. Thereby the important practical question how a chemical bond can be broken is implicitly addressed. This thesis opens (chapter I) with an overview of the available experimental approaches in molecular physics. Further the simple Demkov model for NRCE is described. In chapter II a novel experimental technique for measurements on dissociative processes is introduced which combines a high efficiency with a high energy resolution. A detailed description of the techniques applied in the detector, which has a high spatial and timing resolution with 30 μm and 350 psec FWHM respectively for the detection of one particle, is given in chapter III. A semi-classical theory for NRCE in the medium energy range between a diatomic molecular ion and an atom is developed in chapter IV. The experiments on dissociative charge exchange of H 2 + with Ar, Mg, Na and Cs targets at keV energies are described in Chapter V. The predissociation of the c 3 PIsub(u)-state of H 2 populated after charge exchange of H 2 with several targets at keV energies; is the subject of chapter VI. In chapter VII, orientational oscillations in the cross section for charge exchange of H 2 + with alkali targets are discussed. The last chapter deals with predissociation of highly excited states in H 2 . (Auth.)

Evaluation of unrestrained replica-exchange simulations using dynamic walkers in temperature space for protein structure refinement.

Directory of Open Access Journals (Sweden)

Mark A Olson

Full Text Available A central problem of computational structural biology is the refinement of modeled protein structures taken from either comparative modeling or knowledge-based methods. Simulations are commonly used to achieve higher resolution of the structures at the all-atom level, yet methodologies that consistently yield accurate results remain elusive. In this work, we provide an assessment of an adaptive temperature-based replica exchange simulation method where the temperature clients dynamically walk in temperature space to enrich their population and exchanges near steep energetic barriers. This approach is compared to earlier work of applying the conventional method of static temperature clients to refine a dataset of conformational decoys. Our results show that, while an adaptive method has many theoretical advantages over a static distribution of client temperatures, only limited improvement was gained from this strategy in excursions of the downhill refinement regime leading to an increase in the fraction of native contacts. To illustrate the sampling differences between the two simulation methods, energy landscapes are presented along with their temperature client profiles.

Mechanical calculation of heat exchangers

International Nuclear Information System (INIS)

Osweiller, Francis.

1977-01-01

Many heat exchangers are still being dimensioned at the present time by means of the American TEMA code (Tubular Exchanger Manufacturers Association). The basic formula of this code often gives rise to significant tubular plate thicknesses which, apart from the cost of materials, involve significant machining. Some constructors have brought into use calculation methods that are more analytic so as to take into better consideration the mechanical phenomena which come into play in a heat exchanger. After a brief analysis of these methods it is shown, how the original TEMA formulations have changed to reach the present version and how this code has incorporated Gardner's results for treating exchangers with two fixed heads. A formal and numerical comparison is then made of the analytical and TEMA methods by attempting to highlight a code based on these methods or a computer calculation programme in relation to the TEMA code [fr

Increasing the pump-up rate to polarize 3He gas using spin-exchange optical pumping method

International Nuclear Information System (INIS)

Lee, W.T.; Tong Xin; Rich, Dennis; Liu Yun; Fleenor, Michael; Ismaili, Akbar; Pierce, Joshua; Hagen, Mark; Dadras, Jonny; Robertson, J. Lee

2009-01-01

In recent years, polarized 3 He gas has increasingly been used as neutron polarizers and polarization analyzers. Two of the leading methods to polarize the 3 He gas are the spin-exchange optical pumping (SEOP) method and the meta-stable exchange optical pumping (MEOP) method. At present, the SEOP setup is comparatively compact due to the fact that it does not require the sophisticated compressor system used in the MEOP method. The temperature and the laser power available determine the speed, at which the SEOP method polarizes the 3 He gas. For the quantity of gas typically used in neutron scattering work, this speed is independent of the quantity of the gas required, whereas the polarizing time using the MEOP method is proportional to the quantity of gas required. Currently, using the SEOP method to polarize several bar-liters of 3 He to 70% polarization would require 20-40 h. This is an order of magnitude longer than the MEOP method for the same quantity of gas and polarization. It would therefore be advantageous to speed up the SEOP process. In this article, we analyze the requirements for temperature, laser power, and the type of alkali used in order to shorten the time required to polarize 3 He gas using the SEOP method.

High-capacity cation-exchange column for enhanced resolution of adjacent peaks of cations in ion chromatography.

Science.gov (United States)

Rey, M A

2001-06-22

One of the advantages of ion chromatography [Anal Chem. 47 (1975) 1801] as compared to other analytical techniques is that several ions may be analyzed simultaneously. One of the most important contributions of cation-exchange chromatography is its sensitivity to ammonium ion, which is difficult to analyze by other techniques [J. Weiss, in: E.L. Johnson (Ed.), Handbook of Ion Chromatography, Dionex, Sunnyvale, CA, USA]. The determination of low concentrations of ammonium ion in the presence of high concentrations of sodium poses a challenge in cation-exchange chromatography [J. Weiss, Ion Chromatography, VCH, 2nd Edition, Weinheim, 1995], as both cations have similar selectivities for the common stationary phases containing either sulfonate or carboxylate functional groups. The task was to develop a new cation-exchange stationary phase (for diverse concentration ratios of adjacent peaks) to overcome limitations experienced in previous trails. Various cation-exchange capacities and column body formats were investigated to optimize this application and others. The advantages and disadvantages of two carboxylic acid columns of different cation-exchange capacities and different column formats will be discussed.

Texton-based super-resolution for achieving high spatiotemporal resolution in hybrid camera system

Science.gov (United States)

Kamimura, Kenji; Tsumura, Norimichi; Nakaguchi, Toshiya; Miyake, Yoichi

2010-05-01

Many super-resolution methods have been proposed to enhance the spatial resolution of images by using iteration and multiple input images. In a previous paper, we proposed the example-based super-resolution method to enhance an image through pixel-based texton substitution to reduce the computational cost. In this method, however, we only considered the enhancement of a texture image. In this study, we modified this texton substitution method for a hybrid camera to reduce the required bandwidth of a high-resolution video camera. We applied our algorithm to pairs of high- and low-spatiotemporal-resolution videos, which were synthesized to simulate a hybrid camera. The result showed that the fine detail of the low-resolution video can be reproduced compared with bicubic interpolation and the required bandwidth could be reduced to about 1/5 in a video camera. It was also shown that the peak signal-to-noise ratios (PSNRs) of the images improved by about 6 dB in a trained frame and by 1.0-1.5 dB in a test frame, as determined by comparison with the processed image using bicubic interpolation, and the average PSNRs were higher than those obtained by the well-known Freeman’s patch-based super-resolution method. Compared with that of the Freeman’s patch-based super-resolution method, the computational time of our method was reduced to almost 1/10.

Geneva calling: WHO resolution on mental disorders

Directory of Open Access Journals (Sweden)

Barbui Corrado

2012-06-01

Full Text Available Abstract Background A new resolution on mental, neurological and substance use disorders was adopted in January 2012 by the World Health Organization (WHO Executive Board. The resolution urges WHO and Member States to collaborate in the development of a comprehensive mental health action plan, to be submitted for discussion and approval to the WHO World Health Assembly. This commentary aims at rising awareness on the risk that this resolution may not fulfil its potential. Discussion Lack of political awareness and visibility of the resolution is a first major issue. Theoretically, Member States should be aware of the resolution and support its implementation at their respective national level, but in practice political commitment may not be high enough, and technical and financial resources made available may be limited. A second challenge is that the resolution suggests to work with Member States and technical agencies to promote academic exchange through which to contribute to policy-making in mental health. It is not straightforward, however, how such a statement may be effectively translated into action. A third key methodological aspect is how scientific evidence and factors other than scientific evidence will be handled. This seems particularly relevant in the field of mental health, where value-based decisions together with resource and feasibility considerations may be unavoidable. Summary We argue that WHO and Member States should work together to increase the visibility of the resolution, ensuring that Ministries of Health and other relevant components of the health systems are aware of the resolution and its implications. As the resolution urges for academic exchange, WHO should develop a plan for an explicit, inclusive and open call for support and collaboration, so that partners willing to contribute are not kept out from the process. The production of an action plan for mental disorders should be based on scientifically sound

New high resolution Random Telegraph Noise (RTN) characterization method for resistive RAM

Science.gov (United States)

Maestro, M.; Diaz, J.; Crespo-Yepes, A.; Gonzalez, M. B.; Martin-Martinez, J.; Rodriguez, R.; Nafria, M.; Campabadal, F.; Aymerich, X.

2016-01-01

Random Telegraph Noise (RTN) is one of the main reliability problems of resistive switching-based memories. To understand the physics behind RTN, a complete and accurate RTN characterization is required. The standard equipment used to analyse RTN has a typical time resolution of ∼2 ms which prevents evaluating fast phenomena. In this work, a new RTN measurement procedure, which increases the measurement time resolution to 2 μs, is proposed. The experimental set-up, together with the recently proposed Weighted Time Lag (W-LT) method for the analysis of RTN signals, allows obtaining a more detailed and precise information about the RTN phenomenon.

Nuclide separation by hydrothermal treatment and ion exchange: a highly effective method for treatment of liquid effluents - 59217

International Nuclear Information System (INIS)

Braehler, Georg; Rieck, Ronald; Avramenko, V.A.; Sergienko, V.I.; Antonov, E.A.

2012-01-01

Liquid low level radioactive effluents, when solidified in e.g. cement matrix, contribute to a significant extent to the waste amount to be disposed of in final repositories. Accordingly, since many years scientists and engineers investigate processes to remove the radioactive nuclides selectively from the effluents, to split the raw solution into two separate fractions: a large fraction with activity concentrations below the limits for free release; and a small fraction, containing the activity in concentrated form on e. g. ion exchanger materials (ion exchange has proven to be the most promising method for such 'nuclide separation'). The challenge to be taken up is: When (and this is most often the case) the effluent contains organic materials and complexing agents, the formation of e. g. the 60-Co-EDTA complex prohibits its fixation to the ion exchangers. Accordingly the complexing agent needs to be removed or destroyed. The Institute for Chemistry of the Russian Academy of Sciences has applied the method of hydrothermal treatment (at elevated temperature and pressure, 200 deg. C, 200 bar), supported by Hydrogen Peroxide oxidation, to allow virtually complete removal of radioactive nuclides on inorganic ion exchangers. Pilot plants have been operated successfully in Russian power stations, and an operational plant has been designed. The method is being extended for an interesting and promising application: spent organic ion exchange resins, loaded up to the medium activity level, represent a serious disposal problem. With the hydrothermal process, in a process cycle, the activity can be stripped from the resins, the organic content is destroyed, and the activity is fixed on an inorganic absorber, well suited for final disposal. (authors)

Sorption-spectroscopic and test methods for the determination of metal ions on the solid-phase of ion-exchange materials

International Nuclear Information System (INIS)

Savvin, Sergey B; Dedkova, Valentina P; Shvoeva, Ol'ga P

2000-01-01

Data on sorption-spectroscopic and test methods for the determination of metal ions on the solid-phase of ion-exchange materials published over the past decade are reviewed. The advantages and disadvantages of ion-exchange materials are discussed. The detection limits and selectivity of these techniques are described. The bibliography includes 151 references.

Preparation of Nafion 117™-SnO₂ Composite Membranes using an Ion-Exchange Method

DEFF Research Database (Denmark)

Nørgaard, Casper Frydendal; Nielsen, Ulla Gro; Skou, Eivind Morten

2012-01-01

Nafion 117™-SnO2 composite membranes were prepared by in-situ particle formation using an ion-exchange method. SnO2 was incorporated into Nafion 117ä membranes by ion-exchange in solutions of SnCl2 ∙2 H2O in methanol, followed by oxidation to SnO2 in air. By adjustment of the concentration of SnCl2...... ∙ 2 H2O used in the ion-exchange step, compositions ranging from 2 to 8 wt% SnO2 with SnO2 homogeneously distributed as nanoparticles were obtained. The prepared nanocomposite membranes were characterized by powder XRD, 119Sn MAS NMR spectroscopy, electrochemical impedance spectroscopy, water uptake...

High-efficient method for spectrometric data real time processing with increased resolution of a measuring channel

International Nuclear Information System (INIS)

Ashkinaze, S.I.; Voronov, V.A.; Nechaev, Yu.I.

1988-01-01

Solution of reduction problem as a mean to increase spectrometric tract resolution when it is realized using the digit-by-digit modified method and special strategy, significantly reducing the time of processing, is considered. The results presented confirm that the complex measurement tract plus microcomputer is equivalent to the use of the tract with a higher resolution, and the use of the digit-by-digit modified method permits to process spectrometric information in real time scale

Plasma Exchange for Refractory MDA5 Myositis and ILD

Science.gov (United States)

2017-04-26

plasma exchange, the patient had improvement of hypocarbic respiratory alkalosis and reversal of myositis with resolution of dysphagia/odynophagia and...symptoms with respiratory distress. A five day course of plasmapheresis was initiated on hospital day eight. Subsequently his respiratory acid-base

Fast analysis of quaternary ammonium pesticides in food and beverages using cation-exchange chromatography coupled with isotope-dilution high-resolution mass spectrometry.

Science.gov (United States)

Nardin, Tiziana; Barnaba, Chiara; Abballe, Franco; Trenti, Gianmaria; Malacarne, Mario; Larcher, Roberto

2017-10-01

A fast separation based on cation-exchange liquid chromatography coupled with high-resolution mass spectrometry is proposed for simultaneous determination of chlormequat, difenzoquat, diquat, mepiquat and paraquat in several food and beverage commodities. Solid samples were extracted using a mixture of water/methanol/formic acid (69.6:30:0.4, v/v/v), while liquid samples were ten times diluted with the same solution. Separation was carried out on an experimental length-modified IonPac CS17 column (2 × 15 mm 2 ) that allowed the use of formic acid and acetonitrile as mobile phase. Detection limits for food and beverage matrices were established at 1.5 μg/L for chlormequat, difenzoquat and mepiquat, and 3 μg/L for diquat and paraquat, while for drinking water a pre-analytical sample concentration allowed detection limits of 9 and 20 ng/L, respectively. Precision, as repeatability (RSD%), ranged from 0.2 to 24%, with a median value of 6%, and trueness, as recovery, ranged from 64 to 118%, with a median value of 96%. The method developed was successfully applied to investigate the presence of herbicide residues in commercial commodities (mineral water, orange juice, beer, tea, green coffee bean, toasted coffee powder, cocoa bean, white corn flour, rice and sugar samples). © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Multi-group transport methods for high-resolution neutron activation analysis

International Nuclear Information System (INIS)

Burns, K. A.; Smith, L. E.; Gesh, C. J.; Shaver, M. W.

2009-01-01

The accurate and efficient simulation of coupled neutron-photon problems is necessary for several important radiation detection applications. Examples include the detection of nuclear threats concealed in cargo containers and prompt gamma neutron activation analysis for nondestructive determination of elemental composition of unknown samples. In these applications, high-resolution gamma-ray spectrometers are used to preserve as much information as possible about the emitted photon flux, which consists of both continuum and characteristic gamma rays with discrete energies. Monte Carlo transport is the most commonly used modeling tool for this type of problem, but computational times for many problems can be prohibitive. This work explores the use of multi-group deterministic methods for the simulation of neutron activation problems. Central to this work is the development of a method for generating multi-group neutron-photon cross-sections in a way that separates the discrete and continuum photon emissions so that the key signatures in neutron activation analysis (i.e., the characteristic line energies) are preserved. The mechanics of the cross-section preparation method are described and contrasted with standard neutron-gamma cross-section sets. These custom cross-sections are then applied to several benchmark problems. Multi-group results for neutron and photon flux are compared to MCNP results. Finally, calculated responses of high-resolution spectrometers are compared. Preliminary findings show promising results when compared to MCNP. A detailed discussion of the potential benefits and shortcomings of the multi-group-based approach, in terms of accuracy, and computational efficiency, is provided. (authors)

Contribution to the resolution of algebraic differential equations. Application to electronic circuits and nuclear reactors

International Nuclear Information System (INIS)

Monsef, Youssef.

1977-05-01

This note deals with the resolution of large algebraic differential systems involved in the physical sciences, with special reference to electronics and nuclear physics. The theoretical aspect of the algorithms established and developed for this purpose is discussed in detail. A decomposition algorithm based on the graph theory is developed in detail and the regressive analysis of the error involved in the decomposition is carried out. The specific application of these algorithms on the analyses of non-linear electronic circuits and to the integration of algebraic differential equations simulating the general operation of nuclear reactors coupled to heat exchangers is discussed in detail. To conclude, it is shown that the development of efficient digital resolution techniques dealing with the elements in order is sub-optimal for large systems and calls for the revision of conventional formulation methods. Thus for a high-order physical system, the larger, the number of auxiliary unknowns introduced, the easier the formulation and resolution, owing to the elimination of any form of complex matricial calculation such as those given by the state variables method [fr

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.

Ultrafiltration technique in conjunction with competing ligand exchange method for Ni–humics speciation in aquatic environment

Digital Repository Service at National Institute of Oceanography (India)

Chakraborty, P.; Boissel, M.; Reuillon, A.; Babu, P.V.R.; Parthiban, G.

The combination of ultrafiltration technique with competing ligand exchange method provides a better understanding of interactions between Ni and different molecular weight fractions of humic acid (HA) at varying pH in aquatic environment...

Generator-absorber-heat exchange heat transfer apparatus and method and use thereof in a heat pump

Science.gov (United States)

Phillips, B.A.; Zawacki, T.S.

1998-07-21

Numerous embodiments and related methods for generator-absorber heat exchange (GAX) are disclosed, particularly for absorption heat pump systems. Such embodiments and related methods use, as the heat transfer medium, the working fluid of the absorption system taken from the generator at a location where the working fluid has a rich liquor concentration. 5 figs.

Pixel-Wise Classification Method for High Resolution Remote Sensing Imagery Using Deep Neural Networks

Directory of Open Access Journals (Sweden)

Rui Guo

2018-03-01

Full Text Available Considering the classification of high spatial resolution remote sensing imagery, this paper presents a novel classification method for such imagery using deep neural networks. Deep learning methods, such as a fully convolutional network (FCN model, achieve state-of-the-art performance in natural image semantic segmentation when provided with large-scale datasets and respective labels. To use data efficiently in the training stage, we first pre-segment training images and their labels into small patches as supplements of training data using graph-based segmentation and the selective search method. Subsequently, FCN with atrous convolution is used to perform pixel-wise classification. In the testing stage, post-processing with fully connected conditional random fields (CRFs is used to refine results. Extensive experiments based on the Vaihingen dataset demonstrate that our method performs better than the reference state-of-the-art networks when applied to high-resolution remote sensing imagery classification.

Study on removing nitrate from uranium solution by ion-exchange method

International Nuclear Information System (INIS)

Zhou Genmao

2004-01-01

Nitrate of low concentration can interfere with adsorption of uranyl sulfate anion on anion-exchange resins because the anion-exchange resins have a stronger affinity for nitrate in uranium solution. Nitrate can be adsorbed with a high efficiency resin, then desorbed by sodium hydroxide. The nitrate concentration is about 60 g/L in eluate. The research results show that nitrate can be recovered from uranium solution with N-3 anion-exchange resin

Study of electron-molecule collisions via the finite-element method and R-matrix propagation technique: Model exchange

International Nuclear Information System (INIS)

Abdolsalami, F.; Abdolsalami, M.; Gomez, P.

1994-01-01

We have applied the finite-element method to electron-molecule collisions. All the calculations are done in the body frame within the fixed-nuclei approximation. A model potential, which is added to the static and polarization potential, has been used to represent the exchange effect. The method is applied to electron-H 2 scattering and the eigenphase sums and the cross sections obtained are in very good agreement with the corresponding results from the linear-algebraic approach. Finite-element calculations of the R matrix in the region where the static and exchange interactions are strong, however, has about one-half to one-fourth of the memory requirement of the linear-algebraic technique

FBG Interrogation Method with High Resolution and Response Speed Based on a Reflective-Matched FBG Scheme

Science.gov (United States)

Cui, Jiwen; Hu, Yang; Feng, Kunpeng; Li, Junying; Tan, Jiubin

2015-01-01

In this paper, a high resolution and response speed interrogation method based on a reflective-matched Fiber Bragg Grating (FBG) scheme is investigated in detail. The nonlinear problem of the reflective-matched FBG sensing interrogation scheme is solved by establishing and optimizing the mathematical model. A mechanical adjustment to optimize the interrogation method by tuning the central wavelength of the reference FBG to improve the stability and anti-temperature perturbation performance is investigated. To satisfy the measurement requirements of optical and electric signal processing, a well- designed acquisition circuit board is prepared, and experiments on the performance of the interrogation method are carried out. The experimental results indicate that the optical power resolution of the acquisition circuit border is better than 8 pW, and the stability of the interrogation method with the mechanical adjustment can reach 0.06%. Moreover, the nonlinearity of the interrogation method is 3.3% in the measurable range of 60 pm; the influence of temperature is significantly reduced to 9.5%; the wavelength resolution and response speed can achieve values of 0.3 pm and 500 kHz, respectively. PMID:26184195

Combined cation-exchange and extraction chromatographic method of pre-concentration and concomitant separation of Cu(II) with high molecular mass liquid cation exchanger after its online detection.

Science.gov (United States)

Mandal, B; Roy, U S; Datta, D; Ghosh, N

2011-08-19

A selective method has been developed for the extraction chromatographic trace level separation of Cu(II) with Versatic 10 (liquid cation exchanger) coated on silanised silica gel (SSG-V10). Cu(II) has been extracted from 0.1M acetate buffer at the range of pH 4.0-5.5. The effects of foreign ions, pH, flow-rate, stripping agents on extraction and elution have been investigated. Exchange capacity of the prepared exchanger at different temperatures with respect to Cu(II) has been determined. The extraction equilibrium constant (K(ex)) and different standard thermodynamic parameters have also been calculated by temperature variation method. Positive value of ΔH (7.98 kJ mol⁻¹) and ΔS (0.1916 kJ mol⁻¹) and negative value of ΔG (-49.16 kJ mol⁻¹) indicated that the process was endothermic, entropy gaining and spontaneous. Preconcentration factor was optimized at 74.7 ± 0.2 and the desorption constants K(desorption)¹(1.4 × 10⁻²) and K(desorption)²(9.8 × 10⁻²) were determined. The effect of pH on R(f) values in ion exchange paper chromatography has been investigated. In order to investigate the sorption isotherm, two equilibrium models, the Freundlich and Langmuir isotherms, were analyzed. Cu(II) has been separated from synthetic binary and multi-component mixtures containing various metal ions associated with it in ores and alloy samples. The method effectively permits sequential separation of Cu(II) from synthetic quaternary mixture containing its congeners Bi(III), Sn(II), Hg(II) and Cu(II), Cd(II), Pb(II) of same analytical group. The method was found effective for the selective detection, removal and recovery of Cu(II) from industrial waste and standard alloy samples following its preconcentration on the column. A plausible mechanism for the extraction of Cu(II) has been suggested. Copyright © 2011 Elsevier B.V. All rights reserved.

Improvement of resolution in full-view linear-array photoacoustic computed tomography using a novel adaptive weighting method

Science.gov (United States)

Omidi, Parsa; Diop, Mamadou; Carson, Jeffrey; Nasiriavanaki, Mohammadreza

2017-03-01

Linear-array-based photoacoustic computed tomography is a popular methodology for deep and high resolution imaging. However, issues such as phase aberration, side-lobe effects, and propagation limitations deteriorate the resolution. The effect of phase aberration due to acoustic attenuation and constant assumption of the speed of sound (SoS) can be reduced by applying an adaptive weighting method such as the coherence factor (CF). Utilizing an adaptive beamforming algorithm such as the minimum variance (MV) can improve the resolution at the focal point by eliminating the side-lobes. Moreover, invisibility of directional objects emitting parallel to the detection plane, such as vessels and other absorbing structures stretched in the direction perpendicular to the detection plane can degrade resolution. In this study, we propose a full-view array level weighting algorithm in which different weighs are assigned to different positions of the linear array based on an orientation algorithm which uses the histogram of oriented gradient (HOG). Simulation results obtained from a synthetic phantom show the superior performance of the proposed method over the existing reconstruction methods.

Application of the Oslo method to high resolution gamma spectra

Science.gov (United States)

Simon, A.; Guttormsen, M.; Larsen, A. C.; Beausang, C. W.; Humby, P.

2015-10-01

Hauser-Feshbach statistical model is a widely used tool for calculation of the reaction cross section, in particular for astrophysical processes. The HF model requires as an input an optical potential, gamma-strength function (GSF) and level density (LD) to properly model the statistical properties of the nucleus. The Oslo method is a well established technique to extract GSFs and LDs from experimental data, typically used for gamma-spectra obtained with scintillation detectors. Here, the first application of the Oslo method to high-resolution data obtained using the Ge detectors of the STARLITER setup at TAMU is discussed. The GSFs and LDs extracted from (p,d) and (p,t) reactions on 152154 ,Sm targets will be presented.

Method for ion exchange purification of sodium iodide solution from heavy metals and potassium microimpurities

International Nuclear Information System (INIS)

Smirnov, G.I.; Kachur, N.Ya.; Kostromina, O.N.; Ogorodnikova, A.A.; Khajnakov, S.A.

1990-01-01

A method of deep ion exchange purification of sodium iodide solution from heavy metals (iron, nickel, copper, lead) and potassium microimpurities is developed. The method includes multiple sorption of microimpurities on titanium phosphate with their subsequent desorption by sorbent processing with a solution with a solution of 3-6 N nitric acid, first, and then with a neutral solution of 2 % sodium thiosulfate. The given method permits to increase the purification degree of sodium iodide solution by 25-30 %. 2 tabs

Combining the Pixel-based and Object-based Methods for Building Change Detection Using High-resolution Remote Sensing Images

Directory of Open Access Journals (Sweden)

ZHANG Zhiqiang

2018-01-01

Full Text Available Timely and accurate change detection of buildings provides important information for urban planning and management.Accompanying with the rapid development of satellite remote sensing technology,detecting building changes from high-resolution remote sensing images have received wide attention.Given that pixel-based methods of change detection often lead to low accuracy while object-based methods are complicated for uses,this research proposes a method that combines pixel-based and object-based methods for detecting building changes from high-resolution remote sensing images.First,based on the multiple features extracted from the high-resolution images,a random forest classifier is applied to detect changed building at the pixel level.Then,a segmentation method is applied to segement the post-phase remote sensing image and to get post-phase image objects.Finally,both changed building at the pixel level and post-phase image objects are fused to recognize the changed building objects.Multi-temporal QuickBird images are used as experiment data for building change detection with high-resolution remote sensing images,the results indicate that the proposed method could reduce the influence of environmental difference,such as light intensity and view angle,on building change detection,and effectively improve the accuracies of building change detection.

Input data preprocessing method for exchange rate forecasting via neural network

Directory of Open Access Journals (Sweden)

Antić Dragan S.

2014-01-01

Full Text Available The aim of this paper is to present a method for neural network input parameters selection and preprocessing. The purpose of this network is to forecast foreign exchange rates using artificial intelligence. Two data sets are formed for two different economic systems. Each system is represented by six categories with 70 economic parameters which are used in the analysis. Reduction of these parameters within each category was performed by using the principal component analysis method. Component interdependencies are established and relations between them are formed. Newly formed relations were used to create input vectors of a neural network. The multilayer feed forward neural network is formed and trained using batch training. Finally, simulation results are presented and it is concluded that input data preparation method is an effective way for preprocessing neural network data. [Projekat Ministarstva nauke Republike Srbije, br.TR 35005, br. III 43007 i br. III 44006

Top-Down Hydrogen-Deuterium Exchange Analysis of Protein Structures Using Ultraviolet Photodissociation.

Science.gov (United States)

Brodie, Nicholas I; Huguet, Romain; Zhang, Terry; Viner, Rosa; Zabrouskov, Vlad; Pan, Jingxi; Petrotchenko, Evgeniy V; Borchers, Christoph H

2018-03-06

Top-down hydrogen-deuterium exchange (HDX) analysis using electron capture or transfer dissociation Fourier transform mass spectrometry (FTMS) is a powerful method for the analysis of secondary structure of proteins in solution. The resolution of the method is a function of the degree of fragmentation of backbone bonds in the proteins. While fragmentation is usually extensive near the N- and C-termini, electron capture (ECD) or electron transfer dissociation (ETD) fragmentation methods sometimes lack good coverage of certain regions of the protein, most often in the middle of the sequence. Ultraviolet photodissociation (UVPD) is a recently developed fast-fragmentation technique, which provides extensive backbone fragmentation that can be complementary in sequence coverage to the aforementioned electron-based fragmentation techniques. Here, we explore the application of electrospray ionization (ESI)-UVPD FTMS on an Orbitrap Fusion Lumos Tribrid mass spectrometer to top-down HDX analysis of proteins. We have incorporated UVPD-specific fragment-ion types and fragment-ion mixtures into our isotopic envelope fitting software (HDX Match) for the top-down HDX analysis. We have shown that UVPD data is complementary to ETD, thus improving the overall resolution when used as a combined approach.

Exchange coupling and magnetic anisotropy of exchanged-biased quantum tunnelling single-molecule magnet Ni3Mn2 complexes using theoretical methods based on Density Functional Theory.

Science.gov (United States)

Gómez-Coca, Silvia; Ruiz, Eliseo

2012-03-07

The magnetic properties of a new family of single-molecule magnet Ni(3)Mn(2) complexes were studied using theoretical methods based on Density Functional Theory (DFT). The first part of this study is devoted to analysing the exchange coupling constants, focusing on the intramolecular as well as the intermolecular interactions. The calculated intramolecular J values were in excellent agreement with the experimental data, which show that all the couplings are ferromagnetic, leading to an S = 7 ground state. The intermolecular interactions were investigated because the two complexes studied do not show tunnelling at zero magnetic field. Usually, this exchange-biased quantum tunnelling is attributed to the presence of intermolecular interactions calculated with the help of theoretical methods. The results indicate the presence of weak intermolecular antiferromagnetic couplings that cannot explain the ferromagnetic value found experimentally for one of the systems. In the second part, the goal is to analyse magnetic anisotropy through the calculation of the zero-field splitting parameters (D and E), using DFT methods including the spin-orbit effect.

Knowledge exchange between agents in real-time environments

DEFF Research Database (Denmark)

Frisvad, Jeppe Revall; Falster, Peter; Møller, Gert Lykke

2005-01-01

To obtain unpredictable social interaction between autonomous agents in real-time environments, we present a simple method for logic-based knowledge exchange. A method which is able to form new knowledge rather than do simple exchange of particular rules found in predetermined rule sets. The appl......To obtain unpredictable social interaction between autonomous agents in real-time environments, we present a simple method for logic-based knowledge exchange. A method which is able to form new knowledge rather than do simple exchange of particular rules found in predetermined rule sets...

Continuous Manual Exchange Transfusion for Patients with Sickle Cell Disease: An Efficient Method to Avoid Iron Overload.

Science.gov (United States)

Koehl, Bérengère; Missud, Florence; Holvoet, Laurent; Ithier, Ghislaine; Sakalian-Black, Oliver; Haouari, Zinedine; Lesprit, Emmanuelle; Baruchel, André; Benkerrou, Malika

2017-03-14

Children with sickle cell anemia (SCA) may be at risk of cerebral vasculopathy and strokes, which can be prevented by chronic transfusion programs. Repeated transfusions of packed red blood cells (PRBCs) is currently the simplest and most used technique for chronic transfusion programs. However, iron overload is one of the major side effects of this therapy. More developed methods exist, notably the apheresis of RBC (erythrapheresis), which is currently the safest and most efficient method. However, it is costly, complicated, and cannot be implemented everywhere, nor is it suitable for all patients. Manual exchange transfusions combine one or more manual phlebotomies with a PRBC transfusion. At the Reference Center of Sickle Cell Disease, we set up a continuous method of manual exchange transfusion that is feasible for all hospital settings, demands no specific equipment, and is widely applicable. In terms of HbS decrease, stroke prevention, and iron overload prevention, this method showed comparable efficiency to erythrapheresis. In cases where erythrapheresis is not available, this method can be a good alternative for patients and care centers.

Comparison and validation of dynamic characteristic analytical method for tubular heat exchanger

International Nuclear Information System (INIS)

Huang Qing; Xu Dinggeng; Chen Meng; Shen Rui

2013-01-01

In this study, the natural frequencies of Normal Residual Heat Removal Heat Exchangers are evaluated based on the beam and shell-beam finite element models. The corresponding results are compared and some discrepancies are observed. These discrepancies are analyzed in terms of the analysis of a cylindrical shell and the unreasonable treatment of boundary conditions is accordingly pointed out. The experimental data of the natural frequencies of heat exchangers used for Qinshan Phase Ⅰ Nuclear Power Plant are compared with the computational results from the shell-beam models for corresponding heat exchangers of C-2 program. The experimental and numerical results agree quite well, which implies that the shell-beam finite element simplification is applicable to the heat exchangers. The results indicate that the procedures introduced in this article apply to the dynamic analysis of other similar heat exchangers. (authors)

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...

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.

Comparison of four machine learning methods for object-oriented change detection in high-resolution satellite imagery

Science.gov (United States)

Bai, Ting; Sun, Kaimin; Deng, Shiquan; Chen, Yan

2018-03-01

High resolution image change detection is one of the key technologies of remote sensing application, which is of great significance for resource survey, environmental monitoring, fine agriculture, military mapping and battlefield environment detection. In this paper, for high-resolution satellite imagery, Random Forest (RF), Support Vector Machine (SVM), Deep belief network (DBN), and Adaboost models were established to verify the possibility of different machine learning applications in change detection. In order to compare detection accuracy of four machine learning Method, we applied these four machine learning methods for two high-resolution images. The results shows that SVM has higher overall accuracy at small samples compared to RF, Adaboost, and DBN for binary and from-to change detection. With the increase in the number of samples, RF has higher overall accuracy compared to Adaboost, SVM and DBN.

A sediment extraction and cleanup method for wide-scope multitarget screening by liquid chromatography-high-resolution mass spectrometry.

Science.gov (United States)

Massei, Riccardo; Byers, Harry; Beckers, Liza-Marie; Prothmann, Jens; Brack, Werner; Schulze, Tobias; Krauss, Martin

2018-01-01

Previous studies on organic sediment contaminants focused mainly on a limited number of highly hydrophobic micropollutants accessible to gas chromatography using nonpolar, aprotic extraction solvents. The development of liquid chromatography-high-resolution mass spectrometry (LC-HRMS) permits the spectrum of analysis to be expanded to a wider range of more polar and ionic compounds present in sediments and allows target, suspect, and nontarget screening to be conducted with high sensitivity and selectivity. In this study, we propose a comprehensive multitarget extraction and sample preparation method for characterization of sediment pollution covering a broad range of physicochemical properties that is suitable for LC-HRMS screening analysis. We optimized pressurized liquid extraction, cleanup, and sample dilution for a target list of 310 compounds. Finally, the method was tested on sediment samples from a small river and its tributaries. The results show that the combination of 100 °C for ethyl acetate-acetone (50:50, neutral extract) followed by 80 °C for acetone-formic acid (100:1, acidic extract) and methanol-10 mM sodium tetraborate in water (90:10, basic extract) offered the best extraction recoveries for 287 of 310 compounds. At a spiking level of 1 μg mL -1 , we obtained satisfactory cleanup recoveries for the neutral extract-(93 ± 23)%-and for the combined acidic/basic extracts-(42 ± 16)%-after solvent exchange. Among the 69 compounds detected in environmental samples, we successfully quantified several pharmaceuticals and polar pesticides.

A Cost-effective Method for Resolution Increase of the Twostage Piecewise Linear ADC Used for Sensor Linearization

Directory of Open Access Journals (Sweden)

Jovanović Jelena

2016-02-01

Full Text Available A cost-effective method for resolution increase of a two-stage piecewise linear analog-to-digital converter used for sensor linearization is proposed in this paper. In both conversion stages flash analog-to-digital converters are employed. Resolution increase by one bit per conversion stage is performed by introducing one additional comparator in front of each of two flash analog-to-digital converters, while the converters’ resolutions remain the same. As a result, the number of employed comparators, as well as the circuit complexity and the power consumption originating from employed comparators are for almost 50 % lower in comparison to the same parameters referring to the linearization circuit of the conventional design and of the same resolution. Since the number of employed comparators is significantly reduced according to the proposed method, special modifications of the linearization circuit are needed in order to properly adjust reference voltages of employed comparators.

Fabrication of Cationic Exchange Polystyrene Nanofibers for Drug ...

African Journals Online (AJOL)

Purpose: To prepare polystyrene nanofiber ion exchangers (PSNIE) with surface cation exchange functionality using a new method based on electrospinning and also to optimize crosslinking and sulfonation reactions to obtain PSNIE with maximum ion exchange capacity (IEC). Method: The nanofibers were prepared from ...

Visual quantification of diffuse emphysema with Sakal's method and high-resolution chest CT

International Nuclear Information System (INIS)

Feuerstein, I.M.; McElvaney, N.G.; Simon, T.R.; Hubbard, R.C.; Crystal, R.G.

1990-01-01

This paper determines the accuracy and efficacy of visual quantitation for a diffuse form of pulmonary emphysema with high-resolution CT (HRCT). Twenty- five adults patients with symptomatic emphysema due to α-antitrypsin deficiency prospectively underwent HRCT with 1.5-mm sections, a high-spatial-resolution algorithm, and targeted reconstruction. Photography was performed with narrow lung windows to accentuate diffuse emphysema. Emphysema was then scored with use of a modification of Sakai's extent and severity scoring method. The scans were all scored by the same blinded observer. Pulmonary function testing (PFT), including diffusing capacity measurement, was performed in all patients. Results were statistically correlated with the use of regression analysis

Orbital-dependent exchange-correlation functionals in density-functional theory realized by the FLAPW method

Energy Technology Data Exchange (ETDEWEB)

Betzinger, Markus

2011-12-14

In this thesis, we extended the applicability of the full-potential linearized augmented-plane-wave (FLAPW) method, one of the most precise, versatile and generally applicable electronic structure methods for solids working within the framework of density-functional theory (DFT), to orbital-dependent functionals for the exchange-correlation (xc) energy. Two different schemes that deal with orbital-dependent functionals, the Kohn-Sham (KS) and the generalized Kohn-Sham (gKS) formalism, have been realized. Hybrid functionals, combining some amount of the orbital-dependent exact exchange energy with local or semi-local functionals of the density, are implemented within the gKS scheme. We work in particular with the PBE0 hybrid of Perdew, Burke, and Ernzerhof. Our implementation relies on a representation of the non-local exact exchange potential - its calculation constitutes the most time consuming step in a practical calculation - by an auxiliary mixed product basis (MPB). In this way, the matrix elements of the Hamiltonian corresponding to the non-local potential become a Brillouin-zone (BZ) sum over vector-matrix-vector products. Several techniques are developed and explored to further accelerate our numerical scheme. We show PBE0 results for a variety of semiconductors and insulators. In comparison with experiment, the PBE0 functional leads to improved band gaps and an improved description of localized states. Even for the ferromagnetic semiconductor EuO with localized 4f electrons, the electronic and magnetic properties are correctly described by the PBE0 functional. Subsequently, we discuss the construction of the local, multiplicative exact exchange (EXX) potential from the non-local, orbital-dependent exact exchange energy. For this purpose we employ the optimized effective potential (OEP) method. Central ingredients of the OEP equation are the KS wave-function response and the single-particle density response function. We show that a balance between the LAPW

Orbital-dependent exchange-correlation functionals in density-functional theory realized by the FLAPW method

International Nuclear Information System (INIS)

Betzinger, Markus

2011-01-01

In this thesis, we extended the applicability of the full-potential linearized augmented-plane-wave (FLAPW) method, one of the most precise, versatile and generally applicable electronic structure methods for solids working within the framework of density-functional theory (DFT), to orbital-dependent functionals for the exchange-correlation (xc) energy. Two different schemes that deal with orbital-dependent functionals, the Kohn-Sham (KS) and the generalized Kohn-Sham (gKS) formalism, have been realized. Hybrid functionals, combining some amount of the orbital-dependent exact exchange energy with local or semi-local functionals of the density, are implemented within the gKS scheme. We work in particular with the PBE0 hybrid of Perdew, Burke, and Ernzerhof. Our implementation relies on a representation of the non-local exact exchange potential - its calculation constitutes the most time consuming step in a practical calculation - by an auxiliary mixed product basis (MPB). In this way, the matrix elements of the Hamiltonian corresponding to the non-local potential become a Brillouin-zone (BZ) sum over vector-matrix-vector products. Several techniques are developed and explored to further accelerate our numerical scheme. We show PBE0 results for a variety of semiconductors and insulators. In comparison with experiment, the PBE0 functional leads to improved band gaps and an improved description of localized states. Even for the ferromagnetic semiconductor EuO with localized 4f electrons, the electronic and magnetic properties are correctly described by the PBE0 functional. Subsequently, we discuss the construction of the local, multiplicative exact exchange (EXX) potential from the non-local, orbital-dependent exact exchange energy. For this purpose we employ the optimized effective potential (OEP) method. Central ingredients of the OEP equation are the KS wave-function response and the single-particle density response function. We show that a balance between the LAPW

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

Methods of Thermal Calculations for a Condensing Waste-Heat Exchanger

Directory of Open Access Journals (Sweden)

Rączka Paweł

2014-12-01

Full Text Available The paper presents the algorithms for a flue gas/water waste-heat exchanger with and without condensation of water vapour contained in flue gas with experimental validation of theoretical results. The algorithms were used for calculations of the area of a heat exchanger using waste heat from a pulverised brown coal fired steam boiler operating in a power unit with a capacity of 900 MWe. In calculation of the condensing part, the calculation results obtained with two algorithms were compared (Colburn-Hobler and VDI algorithms. The VDI algorithm allowed to take into account the condensation of water vapour for flue gas temperatures above the temperature of the water dew point. Thanks to this, it was possible to calculate more accurately the required heat transfer area, which resulted in its reduction by 19 %. In addition, the influence of the mass transfer on the heat transfer area was taken into account, which contributed to a further reduction in the calculated size of the heat exchanger - in total by 28% as compared with the Colburn-Hobler algorithm. The presented VDI algorithm was used to design a 312 kW pilot-scale condensing heat exchanger installed in PGE Belchatow power plant. Obtained experimental results are in a good agreement with calculated values.

FBG Interrogation Method with High Resolution and Response Speed Based on a Reflective-Matched FBG Scheme.

Science.gov (United States)

Cui, Jiwen; Hu, Yang; Feng, Kunpeng; Li, Junying; Tan, Jiubin

2015-07-08

In this paper, a high resolution and response speed interrogation method based on a reflective-matched Fiber Bragg Grating (FBG) scheme is investigated in detail. The nonlinear problem of the reflective-matched FBG sensing interrogation scheme is solved by establishing and optimizing the mathematical model. A mechanical adjustment to optimize the interrogation method by tuning the central wavelength of the reference FBG to improve the stability and anti-temperature perturbation performance is investigated. To satisfy the measurement requirements of optical and electric signal processing, a well- designed acquisition circuit board is prepared, and experiments on the performance of the interrogation method are carried out. The experimental results indicate that the optical power resolution of the acquisition circuit border is better than 8 pW, and the stability of the interrogation method with the mechanical adjustment can reach 0.06%. Moreover, the nonlinearity of the interrogation method is 3.3% in the measurable range of 60 pm; the influence of temperature is significantly reduced to 9.5%; the wavelength resolution and response speed can achieve values of 0.3 pm and 500 kHz, respectively.

Relativistic four-component calculations of indirect nuclear spin-spin couplings with efficient evaluation of the exchange-correlation response kernel

Energy Technology Data Exchange (ETDEWEB)

Křístková, Anežka; Malkin, Vladimir G. [Institute of Inorganic Chemistry, Slovak Academy of Sciences, Dúbravská cesta 9, SK-84536 Bratislava (Slovakia); Komorovsky, Stanislav; Repisky, Michal [Centre for Theoretical and Computational Chemistry, University of Tromsø - The Arctic University of Norway, N-9037 Tromsø (Norway); Malkina, Olga L., E-mail: olga.malkin@savba.sk [Institute of Inorganic Chemistry, Slovak Academy of Sciences, Dúbravská cesta 9, SK-84536 Bratislava (Slovakia); Department of Inorganic Chemistry, Comenius University, Bratislava (Slovakia)

2015-03-21

In this work, we report on the development and implementation of a new scheme for efficient calculation of indirect nuclear spin-spin couplings in the framework of four-component matrix Dirac-Kohn-Sham approach termed matrix Dirac-Kohn-Sham restricted magnetic balance resolution of identity for J and K, which takes advantage of the previous restricted magnetic balance formalism and the density fitting approach for the rapid evaluation of density functional theory exchange-correlation response kernels. The new approach is aimed to speedup the bottleneck in the solution of the coupled perturbed equations: evaluation of the matrix elements of the kernel of the exchange-correlation potential. The performance of the new scheme has been tested on a representative set of indirect nuclear spin-spin couplings. The obtained results have been compared with the corresponding results of the reference method with traditional evaluation of the exchange-correlation kernel, i.e., without employing the fitted electron densities. Overall good agreement between both methods was observed, though the new approach tends to give values by about 4%-5% higher than the reference method. On the average, the solution of the coupled perturbed equations with the new scheme is about 8.5 times faster compared to the reference method.

Relativistic four-component calculations of indirect nuclear spin-spin couplings with efficient evaluation of the exchange-correlation response kernel

International Nuclear Information System (INIS)

Křístková, Anežka; Malkin, Vladimir G.; Komorovsky, Stanislav; Repisky, Michal; Malkina, Olga L.

2015-01-01

In this work, we report on the development and implementation of a new scheme for efficient calculation of indirect nuclear spin-spin couplings in the framework of four-component matrix Dirac-Kohn-Sham approach termed matrix Dirac-Kohn-Sham restricted magnetic balance resolution of identity for J and K, which takes advantage of the previous restricted magnetic balance formalism and the density fitting approach for the rapid evaluation of density functional theory exchange-correlation response kernels. The new approach is aimed to speedup the bottleneck in the solution of the coupled perturbed equations: evaluation of the matrix elements of the kernel of the exchange-correlation potential. The performance of the new scheme has been tested on a representative set of indirect nuclear spin-spin couplings. The obtained results have been compared with the corresponding results of the reference method with traditional evaluation of the exchange-correlation kernel, i.e., without employing the fitted electron densities. Overall good agreement between both methods was observed, though the new approach tends to give values by about 4%-5% higher than the reference method. On the average, the solution of the coupled perturbed equations with the new scheme is about 8.5 times faster compared to the reference method

Numerical analysis on interactions between fluid flow and structure deformation in plate-fin heat exchanger by Galerkin method

Science.gov (United States)

Liu, Jing-cheng; Wei, Xiu-ting; Zhou, Zhi-yong; Wei, Zhen-wen

2018-03-01

The fluid-structure interaction performance of plate-fin heat exchanger (PFHE) with serrated fins in large scale air-separation equipment was investigated in this paper. The stress and deformation of fins were analyzed, besides, the interaction equations were deduced by Galerkin method. The governing equations of fluid flow and heat transfer in PFHE were deduced by finite volume method (FVM). The distribution of strain and stress were calculated in large scale air separation equipment and the coupling situation of serrated fins under laminar situation was analyzed. The results indicated that the interactions between fins and fluid flow in the exchanger have significant impacts on heat transfer enhancement, meanwhile, the strain and stress of fins includes dynamic pressure of the sealing head and flow impact with the increase of flow velocity. The impacts are especially significant at the conjunction of two fins because of the non-alignment fins. It can be concluded that the soldering process and channel width led to structure deformation of fins in the exchanger, and degraded heat transfer efficiency.

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.

A Throughfall Collection Method Using Mixed Bed Ion Exchange Resin Columns

Directory of Open Access Journals (Sweden)

Mark E. Fenn

2002-01-01

Full Text Available Measurement of ionic deposition in throughfall is a widely used method for measuring deposition inputs to the forest floor. Many studies have been published, providing a large database of throughfall deposition inputs to forests. However, throughfall collection and analysis is labor intensive and expensive because of the large number of replicate collectors needed and because sample collection and chemical analyses are required on a stochastic precipitation event-based schedule. Therefore we developed and tested a throughfall collector system using a mixed bed ion exchange resin column. We anticipate that this method will typically require only one to three samplings per year. With this method, bulk deposition and bulk throughfall are collected by a funnel or snow tube and ions are retained as the solution percolates through the resin column. Ions retained by the resin are then extracted in the same column with 2N KCl and analyzed for nitrate and ammonium. Deposition values in throughfall from conventional throughfall solution collectors and colocated ion exchange samplers were not significantly different during consecutive 3- and 4-month exposure periods at a high (Camp Paivika; >35 kg N ha-1 year-1 and a low deposition (Barton Flats; 5–9 kg N ha-1 year-1 site in the San Bernardino Mountains in southern California. N deposition in throughfall under mature pine trees at Camp Paivika after 7 months of exposure was extremely high (87 and 92 kg ha-1 based on the two collector types compared to Barton Flats (11 and 13 kg ha-1. A large proportion of the N deposited in throughfall at Camp Paivika occurred as fog drip, demonstrating the importance of fog deposition as an input source of N at this site. By comparison, bulk deposition rates in open areas were 5.1 and 5.4 kg ha-1 at Camp Paivika based on the two collector types, and 1.9 and 3.0 kg ha-1 at Barton Flats.

Probing protein interactions with hydrogen/deuterium exchange and mass spectrometry—A review

International Nuclear Information System (INIS)

Percy, Andrew J.; Rey, Martial; Burns, Kyle M.; Schriemer, David C.

2012-01-01

Highlights: ► Protein chemistry generates mass shifts useful for structure–function studies. ► H/DX supports a powerful mass shift method for protein interaction analysis. ► H/DX mass shifts are useful for determining binding data (K d , off-rates). ► Improved H/DX–MS workflows can accommodate complex protein systems. - Abstract: Assessing the functional outcome of protein interactions in structural terms is a goal of structural biology, however most techniques have a limited capacity for making structure–function determinations with both high resolution and high throughput. Mass spectrometry can be applied as a reader of protein chemistries in order to fill this void, and enable methodologies whereby protein structure–function determinations may be made on a proteome-wide level. Protein hydrogen/deuterium exchange (H/DX) offers a chemical labeling strategy suitable for tracking changes in “dynamic topography” and thus represents a powerful means of monitoring protein structure–function relationships. This review presents the exchange method in the context of interaction analysis. Applications involving interface detection, quantitation of binding, and conformational responses to ligation are discussed, and commentary on recent analytical developments is provided.

Super-resolution for asymmetric resolution of FIB-SEM 3D imaging using AI with deep learning.

Science.gov (United States)

Hagita, Katsumi; Higuchi, Takeshi; Jinnai, Hiroshi

2018-04-12

Scanning electron microscopy equipped with a focused ion beam (FIB-SEM) is a promising three-dimensional (3D) imaging technique for nano- and meso-scale morphologies. In FIB-SEM, the specimen surface is stripped by an ion beam and imaged by an SEM installed orthogonally to the FIB. The lateral resolution is governed by the SEM, while the depth resolution, i.e., the FIB milling direction, is determined by the thickness of the stripped thin layer. In most cases, the lateral resolution is superior to the depth resolution; hence, asymmetric resolution is generated in the 3D image. Here, we propose a new approach based on an image-processing or deep-learning-based method for super-resolution of 3D images with such asymmetric resolution, so as to restore the depth resolution to achieve symmetric resolution. The deep-learning-based method learns from high-resolution sub-images obtained via SEM and recovers low-resolution sub-images parallel to the FIB milling direction. The 3D morphologies of polymeric nano-composites are used as test images, which are subjected to the deep-learning-based method as well as conventional methods. We find that the former yields superior restoration, particularly as the asymmetric resolution is increased. Our super-resolution approach for images having asymmetric resolution enables observation time reduction.

The outline of the processes for lithium isotope separation by ion exchange method

International Nuclear Information System (INIS)

Fujine, Sachio; Saito, Keiichiro; Naruse, Yuji; Shiba, Koreyuki; Kosuge, Masao; Itoi, Toshiaki; Kitsukawa, Tomohiko.

1981-10-01

A plant of lithium isotope separation by displacement chromatography is preliminary designed. The construction expenses of a 100 kg 7 Li/year plant and the unit cost of separation are estimated on the basis of the data taken from the literature, and the feasibility is studied. Experimental equipment of continuous displacement chromatography is set up and is tested with the stable automatic operation. These results indicate that the ion exchange method is promising for industrial lithium isotope separation. (author)

A simple and rapid method for high-resolution visualization of single-ion tracks

Directory of Open Access Journals (Sweden)

Masaaki Omichi

2014-11-01

Full Text Available Prompt determination of spatial points of single-ion tracks plays a key role in high-energy particle induced-cancer therapy and gene/plant mutations. In this study, a simple method for the high-resolution visualization of single-ion tracks without etching was developed through the use of polyacrylic acid (PAA-N, N’-methylene bisacrylamide (MBAAm blend films. One of the steps of the proposed method includes exposure of the irradiated films to water vapor for several minutes. Water vapor was found to promote the cross-linking reaction of PAA and MBAAm to form a bulky cross-linked structure; the ion-track scars were detectable at a nanometer scale by atomic force microscopy. This study demonstrated that each scar is easily distinguishable, and the amount of generated radicals of the ion tracks can be estimated by measuring the height of the scars, even in highly dense ion tracks. This method is suitable for the visualization of the penumbra region in a single-ion track with a high spatial resolution of 50 nm, which is sufficiently small to confirm that a single ion hits a cell nucleus with a size ranging between 5 and 20 μm.

Research on Horizontal Accuracy Method of High Spatial Resolution Remotely Sensed Orthophoto Image

Science.gov (United States)

Xu, Y. M.; Zhang, J. X.; Yu, F.; Dong, S.

2018-04-01

At present, in the inspection and acceptance of high spatial resolution remotly sensed orthophoto image, the horizontal accuracy detection is testing and evaluating the accuracy of images, which mostly based on a set of testing points with the same accuracy and reliability. However, it is difficult to get a set of testing points with the same accuracy and reliability in the areas where the field measurement is difficult and the reference data with high accuracy is not enough. So it is difficult to test and evaluate the horizontal accuracy of the orthophoto image. The uncertainty of the horizontal accuracy has become a bottleneck for the application of satellite borne high-resolution remote sensing image and the scope of service expansion. Therefore, this paper proposes a new method to test the horizontal accuracy of orthophoto image. This method using the testing points with different accuracy and reliability. These points' source is high accuracy reference data and field measurement. The new method solves the horizontal accuracy detection of the orthophoto image in the difficult areas and provides the basis for providing reliable orthophoto images to the users.

A simple and rapid method for high-resolution visualization of single-ion tracks

Energy Technology Data Exchange (ETDEWEB)

Omichi, Masaaki [Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Osaka 565-0871 (Japan); Center for Collaborative Research, Anan National College of Technology, Anan, Tokushima 774-0017 (Japan); Choi, Wookjin; Sakamaki, Daisuke; Seki, Shu, E-mail: seki@chem.eng.osaka-u.ac.jp [Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Osaka 565-0871 (Japan); Tsukuda, Satoshi [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Miyagi 980-8577 (Japan); Sugimoto, Masaki [Japan Atomic Energy Agency, Takasaki Advanced Radiation Research Institute, Gunma, Gunma 370-1292 (Japan)

2014-11-15

Prompt determination of spatial points of single-ion tracks plays a key role in high-energy particle induced-cancer therapy and gene/plant mutations. In this study, a simple method for the high-resolution visualization of single-ion tracks without etching was developed through the use of polyacrylic acid (PAA)-N, N’-methylene bisacrylamide (MBAAm) blend films. One of the steps of the proposed method includes exposure of the irradiated films to water vapor for several minutes. Water vapor was found to promote the cross-linking reaction of PAA and MBAAm to form a bulky cross-linked structure; the ion-track scars were detectable at a nanometer scale by atomic force microscopy. This study demonstrated that each scar is easily distinguishable, and the amount of generated radicals of the ion tracks can be estimated by measuring the height of the scars, even in highly dense ion tracks. This method is suitable for the visualization of the penumbra region in a single-ion track with a high spatial resolution of 50 nm, which is sufficiently small to confirm that a single ion hits a cell nucleus with a size ranging between 5 and 20 μm.

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...

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 Method of Spatial Mapping and Reclassification for High-Spatial-Resolution Remote Sensing Image Classification

Directory of Open Access Journals (Sweden)

Guizhou Wang

2013-01-01

Full Text Available This paper presents a new classification method for high-spatial-resolution remote sensing images based on a strategic mechanism of spatial mapping and reclassification. The proposed method includes four steps. First, the multispectral image is classified by a traditional pixel-based classification method (support vector machine. Second, the panchromatic image is subdivided by watershed segmentation. Third, the pixel-based multispectral image classification result is mapped to the panchromatic segmentation result based on a spatial mapping mechanism and the area dominant principle. During the mapping process, an area proportion threshold is set, and the regional property is defined as unclassified if the maximum area proportion does not surpass the threshold. Finally, unclassified regions are reclassified based on spectral information using the minimum distance to mean algorithm. Experimental results show that the classification method for high-spatial-resolution remote sensing images based on the spatial mapping mechanism and reclassification strategy can make use of both panchromatic and multispectral information, integrate the pixel- and object-based classification methods, and improve classification accuracy.

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.

Comparative study of key exchange and authentication methods in application, transport and network level security mechanisms

Science.gov (United States)

Fathirad, Iraj; Devlin, John; Jiang, Frank

2012-09-01

The key-exchange and authentication are two crucial elements of any network security mechanism. IPsec, SSL/TLS, PGP and S/MIME are well-known security approaches in providing security service to network, transport and application layers; these protocols use different methods (based on their requirements) to establish keying materials and authenticates key-negotiation and participated parties. This paper studies and compares the authenticated key negotiation methods in mentioned protocols.

Comparison of super-resolution benefits for downsampled iages and real low-resolution data

NARCIS (Netherlands)

Peng, Y.; Spreeuwers, Lieuwe Jan; Gökberk, B.; Veldhuis, Raymond N.J.

2013-01-01

Recently, more and more researchers are exploring the benefits of super-resolution methods on low-resolution face recognition. However, often results presented are obtained on downsampled high-resolution face images. Because downsampled images are different from real images taken at low resolution,

Application of Super-Resolution Convolutional Neural Network for Enhancing Image Resolution in Chest CT.

Science.gov (United States)

Umehara, Kensuke; Ota, Junko; Ishida, Takayuki

2017-10-18

In this study, the super-resolution convolutional neural network (SRCNN) scheme, which is the emerging deep-learning-based super-resolution method for enhancing image resolution in chest CT images, was applied and evaluated using the post-processing approach. For evaluation, 89 chest CT cases were sampled from The Cancer Imaging Archive. The 89 CT cases were divided randomly into 45 training cases and 44 external test cases. The SRCNN was trained using the training dataset. With the trained SRCNN, a high-resolution image was reconstructed from a low-resolution image, which was down-sampled from an original test image. For quantitative evaluation, two image quality metrics were measured and compared to those of the conventional linear interpolation methods. The image restoration quality of the SRCNN scheme was significantly higher than that of the linear interpolation methods (p < 0.001 or p < 0.05). The high-resolution image reconstructed by the SRCNN scheme was highly restored and comparable to the original reference image, in particular, for a ×2 magnification. These results indicate that the SRCNN scheme significantly outperforms the linear interpolation methods for enhancing image resolution in chest CT images. The results also suggest that SRCNN may become a potential solution for generating high-resolution CT images from standard CT images.

NACP North American 8-km Net Ecosystem Exchange and Component Fluxes, 2004

Data.gov (United States)

National Aeronautics and Space Administration — ABSTRACT: This data set provides modeled carbon flux estimates at 8-km spatial resolution over North America for the year 2004 of (1) net ecosystem exchange (NEE) of...

NACP North American 8-km Net Ecosystem Exchange and Component Fluxes, 2004

Data.gov (United States)

National Aeronautics and Space Administration — This data set provides modeled carbon flux estimates at 8-km spatial resolution over North America for the year 2004 of (1) net ecosystem exchange (NEE) of carbon...

A Method for Optimal Load Dispatch of a Multi-zone Power System with Zonal Exchange Constraints

Science.gov (United States)

Hazarika, Durlav; Das, Ranjay

2018-04-01

This paper presented a method for economic generation scheduling of a multi-zone power system having inter zonal operational constraints. For this purpose, the generator rescheduling for a multi area power system having inter zonal operational constraints has been represented as a two step optimal generation scheduling problem. At first, the optimal generation scheduling has been carried out for the zone having surplus or deficient generation with proper spinning reserve using co-ordination equation. The power exchange required for the deficit zones and zones having no generation are estimated based on load demand and generation for the zone. The incremental transmission loss formulas for the transmission lines participating in the power transfer process among the zones are formulated. Using these, incremental transmission loss expression in co-ordination equation, the optimal generation scheduling for the zonal exchange has been determined. Simulation is carried out on IEEE 118 bus test system to examine the applicability and validity of the method.

Implementation and assessment of high-resolution numerical methods in TRACE

Energy Technology Data Exchange (ETDEWEB)

Wang, Dean, E-mail: wangda@ornl.gov [Oak Ridge National Laboratory, 1 Bethel Valley RD 6167, Oak Ridge, TN 37831 (United States); Mahaffy, John H.; Staudenmeier, Joseph; Thurston, Carl G. [U.S. Nuclear Regulatory Commission, Washington, DC 20555 (United States)

2013-10-15

Highlights: • Study and implement high-resolution numerical methods for two-phase flow. • They can achieve better numerical accuracy than the 1st-order upwind scheme. • They are of great numerical robustness and efficiency. • Great application for BWR stability analysis and boron injection. -- Abstract: The 1st-order upwind differencing numerical scheme is widely employed to discretize the convective terms of the two-phase flow transport equations in reactor systems analysis codes such as TRACE and RELAP. While very robust and efficient, 1st-order upwinding leads to excessive numerical diffusion. Standard 2nd-order numerical methods (e.g., Lax–Wendroff and Beam–Warming) can effectively reduce numerical diffusion but often produce spurious oscillations for steep gradients. To overcome the difficulties with the standard higher-order schemes, high-resolution schemes such as nonlinear flux limiters have been developed and successfully applied in numerical simulation of fluid-flow problems in recent years. The present work contains a detailed study on the implementation and assessment of six nonlinear flux limiters in TRACE. These flux limiters selected are MUSCL, Van Leer (VL), OSPRE, Van Albada (VA), ENO, and Van Albada 2 (VA2). The assessment is focused on numerical stability, convergence, and accuracy of the flux limiters and their applicability for boiling water reactor (BWR) stability analysis. It is found that VA and MUSCL work best among of the six flux limiters. Both of them not only have better numerical accuracy than the 1st-order upwind scheme but also preserve great robustness and efficiency.

Implementation and assessment of high-resolution numerical methods in TRACE

International Nuclear Information System (INIS)

Wang, Dean; Mahaffy, John H.; Staudenmeier, Joseph; Thurston, Carl G.

2013-01-01

Highlights: • Study and implement high-resolution numerical methods for two-phase flow. • They can achieve better numerical accuracy than the 1st-order upwind scheme. • They are of great numerical robustness and efficiency. • Great application for BWR stability analysis and boron injection. -- Abstract: The 1st-order upwind differencing numerical scheme is widely employed to discretize the convective terms of the two-phase flow transport equations in reactor systems analysis codes such as TRACE and RELAP. While very robust and efficient, 1st-order upwinding leads to excessive numerical diffusion. Standard 2nd-order numerical methods (e.g., Lax–Wendroff and Beam–Warming) can effectively reduce numerical diffusion but often produce spurious oscillations for steep gradients. To overcome the difficulties with the standard higher-order schemes, high-resolution schemes such as nonlinear flux limiters have been developed and successfully applied in numerical simulation of fluid-flow problems in recent years. The present work contains a detailed study on the implementation and assessment of six nonlinear flux limiters in TRACE. These flux limiters selected are MUSCL, Van Leer (VL), OSPRE, Van Albada (VA), ENO, and Van Albada 2 (VA2). The assessment is focused on numerical stability, convergence, and accuracy of the flux limiters and their applicability for boiling water reactor (BWR) stability analysis. It is found that VA and MUSCL work best among of the six flux limiters. Both of them not only have better numerical accuracy than the 1st-order upwind scheme but also preserve great robustness and efficiency

Extraction Method for Earthquake-Collapsed Building Information Based on High-Resolution Remote Sensing

International Nuclear Information System (INIS)

Chen, Peng; Wu, Jian; Liu, Yaolin; Wang, Jing

2014-01-01

At present, the extraction of earthquake disaster information from remote sensing data relies on visual interpretation. However, this technique cannot effectively and quickly obtain precise and efficient information for earthquake relief and emergency management. Collapsed buildings in the town of Zipingpu after the Wenchuan earthquake were used as a case study to validate two kinds of rapid extraction methods for earthquake-collapsed building information based on pixel-oriented and object-oriented theories. The pixel-oriented method is based on multi-layer regional segments that embody the core layers and segments of the object-oriented method. The key idea is to mask layer by layer all image information, including that on the collapsed buildings. Compared with traditional techniques, the pixel-oriented method is innovative because it allows considerably rapid computer processing. As for the object-oriented method, a multi-scale segment algorithm was applied to build a three-layer hierarchy. By analyzing the spectrum, texture, shape, location, and context of individual object classes in different layers, the fuzzy determined rule system was established for the extraction of earthquake-collapsed building information. We compared the two sets of results using three variables: precision assessment, visual effect, and principle. Both methods can extract earthquake-collapsed building information quickly and accurately. The object-oriented method successfully overcomes the pepper salt noise caused by the spectral diversity of high-resolution remote sensing data and solves the problem of same object, different spectrums and that of same spectrum, different objects. With an overall accuracy of 90.38%, the method achieves more scientific and accurate results compared with the pixel-oriented method (76.84%). The object-oriented image analysis method can be extensively applied in the extraction of earthquake disaster information based on high-resolution remote sensing

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

Choice of spatial resolution measurement methods to implement: considerations under a “New Laboratory”-scenario for imaging optical testing and research

CSIR Research Space (South Africa)

Theron, B

2013-04-01

Full Text Available A key imaging quality metric for an optical system (e.g. a camera or surveillance device) is its resolution. Methods to measure this, range from visual observation methods on resolution target charts, through more rigorous characterization, e...

Theoretical study of annealed proton-exchanged Nd $LiNbO_{3}$ channel waveguide lasers with variational method

CERN Document Server

De Long Zhang; Yuan Guo Xie; Guilan, Ding; Yuming, Cui; Cai He Chen

2001-01-01

The controllable fabrication parameters, including anneal time, initial exchange time, channel width, dependences of TM/sub 00/ mode size, corresponding effective refractive index, effective pump area, and coupling efficiency between pump and laser modes in z-cut annealed proton-exchanged (APE) Nd:LiNbO/sub 3/ channel waveguide lasers were studied by using variational method. The effect of channel width on the surface index increment and the waveguide depth was taken into account. The features of mode size and effective refractive index were summarized, discussed, and compared with previously published experimental results. The effective pump area, which is directly proportional to threshold pump power, increases strongly, slightly, and very slightly with the increase of anneal time, channel width, and initial exchange time, respectively. However, the coupling efficiency, which is directly proportional to slope efficiency, remains constant (around 0.82) no matter what changes made to these parameters. The var...

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.

Cryptographic Combinatorial Securities Exchanges

Science.gov (United States)

Thorpe, Christopher; Parkes, David C.

We present a useful new mechanism that facilitates the atomic exchange of many large baskets of securities in a combinatorial exchange. Cryptography prevents information about the securities in the baskets from being exploited, enhancing trust. Our exchange offers institutions who wish to trade large positions a new alternative to existing methods of block trading: they can reduce transaction costs by taking advantage of other institutions’ available liquidity, while third party liquidity providers guarantee execution—preserving their desired portfolio composition at all times. In our exchange, institutions submit encrypted orders which are crossed, leaving a “remainder”. The exchange proves facts about the portfolio risk of this remainder to third party liquidity providers without revealing the securities in the remainder, the knowledge of which could also be exploited. The third parties learn either (depending on the setting) the portfolio risk parameters of the remainder itself, or how their own portfolio risk would change if they were to incorporate the remainder into a portfolio they submit. In one setting, these third parties submit bids on the commission, and the winner supplies necessary liquidity for the entire exchange to clear. This guaranteed clearing, coupled with external price discovery from the primary markets for the securities, sidesteps difficult combinatorial optimization problems. This latter method of proving how taking on the remainder would change risk parameters of one’s own portfolio, without revealing the remainder’s contents or its own risk parameters, is a useful protocol of independent interest.

Probable causes of damage of heat-exchange tubes of low-pressure-exchanges of PND-3 type and repair methods

Science.gov (United States)

Trifonov, N. N.; Esin, S. B.; Nikolaenkova, E. K.; Sukhorukov, Yu. G.; Svyatkin, F. A.; Sintsova, T. G.; Modestov, V. S.

2017-08-01

The structures of low-pressure heaters (LPH), which are installed at nuclear power plants with the K-1000-60/1500 type turbine plants are considered. It was revealed that only the PND-3 type low-pressure heaters have the damages of the heat exchange tubes. For a short operation life, the number of the damaged heat-exchange tubes of PND-3 is approximately 50 pcs for Kalinin NPP and 100-150 pcs for Balakovo NPP. The low-pressure heaters were manufactured at AO Ural Plant of Chemical Machine-Building "Uralkhimmash," OAO Taganrog Boiler-Making Works "Krasny Kotelshchik," and Vitkovice Machinery Group, but the damage nature of the heat-exchange tubes is identical for all PND-3. The damages occur in the place of passage of the heat exchange tubes through the first, the second, and the third partitions over the lower tube plate (the first path of the turbine condensate). Hydraulic shocks can be one of the possible causes of the damage of the heat-exchange tubes of PND-3. The analysis of the average thermal and dynamic loads of the tube systems of PND-1-PND-4 revealed that PND-3 by the thermal power are loaded 1.4-1.6 times and by the dynamic effects are loaded 1.8-2.0 times more than the remaining LPHs. Another possible cause of damage can be the cascaded drain of the separate into PND-4 and then through the drainage heat exchange into PND-3. An additional factor can be the structure of the condensate drainage unit. The advanced system of the heating steam flow and pumping scheme of the separate drain using the existing drainage pumps of PND-3 for K-1000-60/1500 turbine plants for Balakovo and Kalinin NPPs were proposed. The considered decisions make it possible to reduce the flow rate of the heating steam condensate from PND-3 into PND-4 and the speed of the heating steam in the tube space of PND-3 and eliminate the occurrence of hydraulic shocks and damages of the heat exchanger tubes.

A new MUSIC electromagnetic imaging method with enhanced resolution for small inclusions

Energy Technology Data Exchange (ETDEWEB)

Zhong Yu; Chen Xudong [Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576 (Singapore)], E-mail: zhongyu@nus.edu.sg

2008-11-01

This paper investigates the influence of test dipole on the resolution of the multiple signal classification (MUSIC) imaging method applied to the electromagnetic inverse scattering problem of determining the locations of a collection of small objects embedded in a known background medium. Based on the analysis of the induced electric dipoles in eigenstates, an algorithm is proposed to determine the test dipole that generates a pseudo-spectrum with enhanced resolution. The amplitudes in three directions of the optimal test dipole are not necessarily in phase, i.e., the optimal test dipole may not correspond to a physical direction in the real three-dimensional space. In addition, the proposed test-dipole-searching algorithm is able to deal with some special scenarios, due to the shapes and materials of objects, to which the standard MUSIC doesn't apply.

A new MUSIC electromagnetic imaging method with enhanced resolution for small inclusions

International Nuclear Information System (INIS)

Zhong Yu; Chen Xudong

2008-01-01

This paper investigates the influence of test dipole on the resolution of the multiple signal classification (MUSIC) imaging method applied to the electromagnetic inverse scattering problem of determining the locations of a collection of small objects embedded in a known background medium. Based on the analysis of the induced electric dipoles in eigenstates, an algorithm is proposed to determine the test dipole that generates a pseudo-spectrum with enhanced resolution. The amplitudes in three directions of the optimal test dipole are not necessarily in phase, i.e., the optimal test dipole may not correspond to a physical direction in the real three-dimensional space. In addition, the proposed test-dipole-searching algorithm is able to deal with some special scenarios, due to the shapes and materials of objects, to which the standard MUSIC doesn't apply.

Calibration of high resolution digital camera based on different photogrammetric methods

International Nuclear Information System (INIS)

Hamid, N F A; Ahmad, A

2014-01-01

This paper presents method of calibrating high-resolution digital camera based on different configuration which comprised of stereo and convergent. Both methods are performed in the laboratory and in the field calibration. Laboratory calibration is based on a 3D test field where a calibration plate of dimension 0.4 m × 0.4 m with grid of targets at different height is used. For field calibration, it uses the same concept of 3D test field which comprised of 81 target points located on a flat ground and the dimension is 9 m × 9 m. In this study, a non-metric high resolution digital camera called Canon Power Shot SX230 HS was calibrated in the laboratory and in the field using different configuration for data acquisition. The aim of the calibration is to investigate the behavior of the internal digital camera whether all the digital camera parameters such as focal length, principal point and other parameters remain the same or vice-versa. In the laboratory, a scale bar is placed in the test field for scaling the image and approximate coordinates were used for calibration process. Similar method is utilized in the field calibration. For both test fields, the digital images were acquired within short period using stereo and convergent configuration. For field calibration, aerial digital images were acquired using unmanned aerial vehicle (UAV) system. All the images were processed using photogrammetric calibration software. Different calibration results were obtained for both laboratory and field calibrations. The accuracy of the results is evaluated based on standard deviation. In general, for photogrammetric applications and other applications the digital camera must be calibrated for obtaining accurate measurement or results. The best method of calibration depends on the type of applications. Finally, for most applications the digital camera is calibrated on site, hence, field calibration is the best method of calibration and could be employed for obtaining accurate

Methods of Conflict Resolution in African Traditional Society | Ajayi ...

African Journals Online (AJOL)

This study examined the patterns or mechanism for conflict resolution in traditional African societies with particular reference to Yoruba and Igbo societies in Nigeria and Pondo tribe in South Africa. The paper notes that conflict resolution in traditional African societies provides opportunity to interact with the parties ...

Methods and apparatus for multi-resolution replication of files in a parallel computing system using semantic information

Science.gov (United States)

Faibish, Sorin; Bent, John M.; Tzelnic, Percy; Grider, Gary; Torres, Aaron

2015-10-20

Techniques are provided for storing files in a parallel computing system using different resolutions. A method is provided for storing at least one file generated by a distributed application in a parallel computing system. The file comprises one or more of a complete file and a sub-file. The method comprises the steps of obtaining semantic information related to the file; generating a plurality of replicas of the file with different resolutions based on the semantic information; and storing the file and the plurality of replicas of the file in one or more storage nodes of the parallel computing system. The different resolutions comprise, for example, a variable number of bits and/or a different sub-set of data elements from the file. A plurality of the sub-files can be merged to reproduce the file.

Parametric study on design fractors for the SCS heat exchanger using the Taguchi method

International Nuclear Information System (INIS)

Kim, S. H.; Choi, B. S.; Yoon, J. H.; Jang, M. H.

2002-01-01

Using Taguchi method, design factors, i.e. control factors of the shutdown cooling heat exchanger were investigated to qualify the effect for the time elapsed after the beginning of the system operation. Levels of the control factors were selected from calculations based on the effectiveness-NTU method. From 18 simulations with the KDESCENT program, it was found that the performance of the system is greatly influenced by inlet temperature from the component cooling water at the shell side and mass flow rate of the reactor coolant at the tube side. The Taguchi method makes it possible to select the control factor that has to be controlled and designed with caution. The method gives the effective way to estimate the influence of each control factor to the system performance

WE-EF-303-04: An Advanced Image Processing Method to Improve the Spatial Resolution of Proton Radiographies

International Nuclear Information System (INIS)

Rinaldi, I; Parodi, K; Krah, N

2015-01-01

Purpose: We present an optimization method to improve the spatial resolution and the water equivalent thickness accuracy of proton radiographies. Methods: The method is designed for imaging systems measuring only the residual range of protons without relying on tracker detectors to determine the beam trajectory before and after the target. Specifically, the method was used for an imaging set-up consisting of a stack of 61 parallel-plate ionization chambers (PPIC) working as a range telescope. The method uses a decomposition approach of the residual range signal measured by the PPIC and constructs subimages with small size pixels geometrically rearranged and appropriately averaged to be merged into a final single radiography. The method was tested using Monte Carlo simulated and experimental proton radiographies of a PMMA step phantom and an anthropomorphic head phantom. Results: For the step phantom, the effective spatial resolution was found to be 4 and 3 times higher than the nominal resolution for the simulated and experimental radiographies, respectively. For the head phantom, a gamma index was calculated to quantify the conformity of the simulated proton radiographies with a digitally reconstructed X-ray radiography convolved with a Gaussian kernel equal to the proton beam spot-size. For DTA=2.5 mm and RD=2.5%, the passing ratio was 100%/85% for the optimized/non-optimized case, respectively. An extension of the method allows reducing the dose given to the patient during radiography acquisition. We show that despite a dose reduction of 25 times (leading to a dose of 0.016 mGy for the current imaging set-up), the image quality of the optimized radiographies remains fairly unaffected for both the simulated and experimental results. Conclusion: The optimization method leads to a significant increase of the spatial resolution allowing recovering image details that are unresolved in non-optimized radiographies. These results represent a major step towards clinical

Researching Online Foreign Language Interaction and Exchange: Theories, Methods and Challenges. Telecollaboration in Education. Volume 3

Science.gov (United States)

Dooly, Melinda; O'Dowd, Robert

2012-01-01

This book provides an accessible introduction to some of the methods and theoretical approaches for investigating foreign language (FL) interaction and exchange in online environments. Research approaches which can be applied to Computer-Mediated Communication (CMC) are outlined, followed by discussion of the way in which tools and techniques for…

A new method for measuring temporal resolution in electrocardiogram-gated reconstruction image with area-detector computed tomography

International Nuclear Information System (INIS)

Kaneko, Takeshi; Takagi, Masachika; Kato, Ryohei; Anno, Hirofumi; Kobayashi, Masanao; Yoshimi, Satoshi; Sanda, Yoshihiro; Katada, Kazuhiro

2012-01-01

The purpose of this study was to design and construct a phantom for using motion artifact in the electrocardiogram (ECG)-gated reconstruction image. In addition, the temporal resolution under various conditions was estimated. A stepping motor was used to move the phantom over an arc in a reciprocating manner. The program for controlling the stepping motor permitted the stationary period and the heart rate to be adjusted as desired. Images of the phantom were obtained using a 320-row area-detector computed tomography (ADCT) system under various conditions using the ECG-gated reconstruction method. For estimation, the reconstruction phase was continuously changed and the motion artifacts were quantitatively assessed. The temporal resolution was calculated from the number of motion-free images. Changes in the temporal resolution according to heart rate, rotation time, the number of reconstruction segments and acquisition position in z-axis were also investigated. The measured temporal resolution of ECG-gated half reconstruction is 180 ms, which is in good agreement with the nominal temporal resolution of 175 ms. The measured temporal resolution of ECG-gated segmental reconstruction is in good agreement with the nominal temporal resolution in most cases. The estimated temporal resolution improved to approach the nominal temporal resolution as the number of reconstruction segments was increased. Temporal resolution in changing acquisition position is equal. This study shows that we could design a new phantom for estimating temporal resolution. (author)

A morphologically preserved multi-resolution TIN surface modeling and visualization method for virtual globes

Science.gov (United States)

Zheng, Xianwei; Xiong, Hanjiang; Gong, Jianya; Yue, Linwei

2017-07-01

Virtual globes play an important role in representing three-dimensional models of the Earth. To extend the functioning of a virtual globe beyond that of a "geobrowser", the accuracy of the geospatial data in the processing and representation should be of special concern for the scientific analysis and evaluation. In this study, we propose a method for the processing of large-scale terrain data for virtual globe visualization and analysis. The proposed method aims to construct a morphologically preserved multi-resolution triangulated irregular network (TIN) pyramid for virtual globes to accurately represent the landscape surface and simultaneously satisfy the demands of applications at different scales. By introducing cartographic principles, the TIN model in each layer is controlled with a data quality standard to formulize its level of detail generation. A point-additive algorithm is used to iteratively construct the multi-resolution TIN pyramid. The extracted landscape features are also incorporated to constrain the TIN structure, thus preserving the basic morphological shapes of the terrain surface at different levels. During the iterative construction process, the TIN in each layer is seamlessly partitioned based on a virtual node structure, and tiled with a global quadtree structure. Finally, an adaptive tessellation approach is adopted to eliminate terrain cracks in the real-time out-of-core spherical terrain rendering. The experiments undertaken in this study confirmed that the proposed method performs well in multi-resolution terrain representation, and produces high-quality underlying data that satisfy the demands of scientific analysis and evaluation.

A new automated assign and analysing method for high-resolution rotationally resolved spectra using genetic algorithms

NARCIS (Netherlands)

Meerts, W.L.; Schmitt, M.

2006-01-01

This paper describes a numerical technique that has recently been developed to automatically assign and fit high-resolution spectra. The method makes use of genetic algorithms (GA). The current algorithm is compared with previously used analysing methods. The general features of the GA and its

Patient-specific quantification of image quality: An automated method for measuring spatial resolution in clinical CT images

Energy Technology Data Exchange (ETDEWEB)

Sanders, Jeremiah, E-mail: jeremiah.sanders@duke.edu [Medical Physics Graduate Program, Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Clinical Imaging Physics Group, Duke University, Durham, North Carolina 27710 (United States); Hurwitz, Lynne [Department of Radiology, Duke University, Durham, North Carolina 27710 (United States); Samei, Ehsan [Medical Physics Graduate Program, Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Clinical Imaging Physics Group, Duke University, Durham, North Carolina 27710 and Departments of Physics, Biomedical Engineering, Electrical and Computer Engineering, Duke University, Durham, North Carolina 27710 (United States)

2016-10-15

Purpose: To develop and validate an automated technique for evaluating the spatial resolution characteristics of clinical computed tomography (CT) images. Methods: Twenty one chest and abdominopelvic clinical CT datasets were examined in this study. An algorithm was developed to extract a CT resolution index (RI) analogous to the modulation transfer function from clinical CT images by measuring the edge-spread function (ESF) across the patient’s skin. A polygon mesh of the air-skin boundary was created. The faces of the mesh were then used to measure the ESF across the air-skin interface. The ESF was differentiated to obtain the line-spread function (LSF), and the LSF was Fourier transformed to obtain the RI. The algorithm’s ability to detect the radial dependence of the RI was investigated. RIs measured with the proposed method were compared with a conventional phantom-based method across two reconstruction algorithms (FBP and iterative) using the spatial frequency at 50% RI, f{sub 50}, as the metric for comparison. Three reconstruction kernels were investigated for each reconstruction algorithm. Finally, an observer study was conducted to determine if observers could visually perceive the differences in the measured blurriness of images reconstructed with a given reconstruction method. Results: RI measurements performed with the proposed technique exhibited the expected dependencies on the image reconstruction. The measured f{sub 50} values increased with harder kernels for both FBP and iterative reconstruction. Furthermore, the proposed algorithm was able to detect the radial dependence of the RI. Patient-specific measurements of the RI were comparable to the phantom-based technique, but the patient data exhibited a large spread in the measured f{sub 50}, indicating that some datasets were blurrier than others even when the projection data were reconstructed with the same reconstruction algorithm and kernel. Results from the observer study substantiated this

Determination of mycophenolic acid in mest products using mixed mode reversed phase-anion exchange clean-up and liquid chromatography-high-resolution mass spectrometry

DEFF Research Database (Denmark)

Sørensen, Louise Marie; Nielsen, Kristian Fog; Jacobsen, Thomas

2008-01-01

A method for determination of mycophenolic acid (MPA) in dry-cured ham, fermented sausage and liver pate is described. MPA was extracted from meat with bicarbonate-acetonitrile, further cleaned-up by mixed mode reversed phase-anion exchange and detected using a LC-MS system with electrospray...

Resolution enhancement for ultrasonic echographic technique in non destructive testing with an adaptive deconvolution method

International Nuclear Information System (INIS)

Vivet, L.

1989-01-01

The ultrasonic echographic technique has specific advantages which makes it essential in a lot of Non Destructive Testing (NDT) investigations. However, the high acoustic power necessary to propagate through highly attenuating media can only be transmitted by resonant transducers, which induces severe limitations of the resolution on the received echograms. This resolution may be improved with deconvolution methods. But one-dimensional deconvolution methods come up against problems in non destructive testing when the investigated medium is highly anisotropic and inhomogeneous (i.e. austenitic steel). Numerous deconvolution techniques are well documented in the NDT literature. But they often come from other application fields (biomedical engineering, geophysics) and we show they do not apply well to specific NDT problems: frequency-dependent attenuation and non-minimum phase of the emitted wavelet. We therefore introduce a new time-domain approach which takes into account the wavelet features. Our method solves the deconvolution problem as an estimation one and is performed in two steps: (i) A phase correction step which takes into account the phase of the wavelet and estimates a phase-corrected echogram. The phase of the wavelet is only due to the transducer and is assumed time-invariant during the propagation. (ii) A band equalization step which restores the spectral content of the ideal reflectivity. The two steps of the method are performed using fast Kalman filters which allow a significant reduction of the computational effort. Synthetic and actual results are given to prove that this is a good approach for resolution improvement in attenuating media [fr

Magnetic exchange in {Gd(III)-radical} complexes: method assessment, mechanism of coupling and magneto-structural correlations.

Science.gov (United States)

Gupta, Tulika; Rajeshkumar, Thayalan; Rajaraman, Gopalan

2014-07-28

Density functional studies have been performed on ten different {Gd(III)-radical} complexes exhibiting both ferro and antiferromagnetic exchange interaction with an aim to assess a suitable exchange-correlation functional within DFT formalism. This study has also been extended to probe the mechanism of magnetic coupling and to develop suitable magneto-structural correlations for this pair. Our method assessments reveal the following order of increasing accuracy for the evaluation of J values compared to experimental coupling constants: B(40HF)LYP X3LYP < B3LYP < B2PLYP. Grimme's double-hybrid functional is found to be superior compared to other functionals tested and this is followed very closely by the conventional hybrid B3LYP functional. At the basis set front, our calculations reveal that the incorporation of relativistic effect is important in these calculations and the relativistically corrected effective core potential (ECP) basis set is found to yield better Js compared to other methods. The supposedly empty 5d/6s/6p orbitals of Gd(III) are found to play an important role in the mechanism of magnetic coupling and different contributions to the exchange terms are probed using Molecular Orbital (MO) and Natural Bond Orbital (NBO) analysis. Magneto-structural correlations for Gd-O distances, Gd-O-N angles and Gd-O-N-C dihedral angles are developed where the bond angles as well as dihedral angle parameters are found to dictate the sign and strength of the magnetic coupling in this series.

Use of the ion exchange method for determination of stability constants of uranyl ions with three soil humic acids

International Nuclear Information System (INIS)

Tao Zuyi; Du Jinzhou

1994-01-01

The ion exchange equilibrium method proposed by Ardakani and Stevenson has not been widely used to determine the stability constants of metal-soil organic matter complexes. In this paper the Ardakani-Stevenson's method has been modified and the stability constants of uranyl ion complexes with three soil humic acids were determined by using the modified Ardakani-Stevenson's method. (orig.)

AN EXPERIMENTAL ASSESSMENT OF THE PLATE HEAT EXCHANGER CHARACTERISTICS BY WILSON PLOT METHOD

Directory of Open Access Journals (Sweden)

Jan Opatřil

2016-10-01

Full Text Available An aim of this paper is suggestion of the evaluation method based on the experimental data and the Wilson plot method for the Plate Heat Exchangers (PHE. For the purpose of the project the new experimental loop was built for the testing of PHE to obtain the overhaul heat transfer coefficient and pressure drop between inlet and outlet of the fluid. The measurement were done for three different PHE with the performance range 30-100kW. The working fluid was water on both sides of the PHE. The differences are in number of pates as well as in extrusion profiles. The Wilson plot evaluation method was involved for the processing experimental data. To obtain more accurate correlations between the experimental data and theoretical results yield of the Wilson plot, the method was enhanced by the measured pressure drop involving. This approach could be useful for PHE designing software and for the manufacturing company.

AIRCRAFT CONFLICTS RESOLUTION BY COURSE MANEUVERING

Directory of Open Access Journals (Sweden)

В. Харченко

2011-02-01

Full Text Available Enhancement of requirements for air traffic efficiency at increasing of flights intensity determines the necessity of development of new optimization methods for aircraft conflict resolutions. The statement of problem of optimal conflict resolutions at Cooperative Air Traffic Management was done. The method for optimal aircraft conflict  resolution by course maneuvering has been  developed. The method using dynamic programming provides planning of aircraft conflict-free trajectory with minimum length. The decomposition of conflict resolution process on phases and stages, definition of states, controls and recursive  equations for generation of optimal course control program were done. Computer modeling of aircraft conflict resolution by developed method was done

Transendothelial lipoprotein exchange and microalbuminuria

DEFF Research Database (Denmark)

Jensen, Jan Skov; Feldt-Rasmussen, Bo; Jensen, Kurt Svarre

2004-01-01

OBJECTIVE: Microalbuminuria associates with increased risk of atherosclerosis in individuals without diabetes. We hypothesized that transendothelial lipoprotein exchange is elevated among such individuals, possibly explaining increased intimal lipoprotein accumulation and thus atherosclerosis....... METHODS: Using an in vivo isotope technique, transendothelial exchange of low density lipoprotein (LDL) was measured in 77 non-diabetic individuals. Autologous 131-iodinated LDL was reinjected intravenously, and the 1-h fractional escape rate was calculated as index of transendothelial exchange. RESULTS......: There was no difference in transendothelial LDL exchange between subjects with microalbuminuria versus normoalbuminuria (mean (95% confidence interval) 3.8%/h (3.3-4.3%/h) versus 4.2%/h (3.7-4.7%/h); P=0.33). In contrast, there was a positive correlation between transendothelial LDL exchange and (logarithmically...

Preparation of very small point sources for high resolution radiography

International Nuclear Information System (INIS)

Case, F.N.

1976-01-01

The need for very small point sources of high specific activity 192 Ir, 169 Yb, 170 Tm, and 60 Co in non-destructive testing has motivated the development of techniques for the fabrication of these sources. To prepare 192 Ir point sources for use in examination of tube sheet welds in LMFBR heat exchangers, 191 Ir enriched to greater than 90 percent was melted in a helium blanketed arc to form spheres as small as 0.38 mm in diameter. Methods were developed to form the roughly spherical shaped arc product into nearly symmetrical spheres that could be used for high resolution radiography. Similar methods were used for spherical shaped sources of 169 Yb and 170 Tm. The oxides were arc melted to form rough spheres followed by grinding to precise dimensions, neutron irradiation of the spheres at a flux of 2 to 3 x 10 15 nv, and use of enriched 168 Yb to provide the maximum specific activity. Cobalt-60 with a specific activity of greater than 1100 Ci/g was prepared by processing 59 Co that had been neutron irradiated to nearly complete burnup of the 59 Co target to produce 60 Co, 61 Ni, and 62 Ni. Ion exchange methods were used to separate the cobalt from the nickel. The cobalt was reduced to metal by plating either onto aluminum foil which was dissolved away from the cobalt plate, or by plating onto mercury to prepare amalgam that could be easily formed into a pellet of cobalt with exclusion of the mercury. Both methods are discussed

Comparison of online and offline based merging methods for high resolution rainfall intensities

Science.gov (United States)

Shehu, Bora; Haberlandt, Uwe

2016-04-01

Accurate rainfall intensities with high spatial and temporal resolution are crucial for urban flow prediction. Commonly, raw or bias corrected radar fields are used for forecasting, while different merging products are employed for simulation. The merging products are proven to be adequate for rainfall intensities estimation, however their application in forecasting is limited as they are developed for offline mode. This study aims at adapting and refining the offline merging techniques for the online implementation, and at comparing the performance of these methods for high resolution rainfall data. Radar bias correction based on mean fields and quantile mapping are analyzed individually and also are implemented in conditional merging. Special attention is given to the impact of different spatial and temporal filters on the predictive skill of all methods. Raw radar data and kriging interpolation of station data are considered as a reference to check the benefit of the merged products. The methods are applied for several extreme events in the time period 2006-2012 caused by different meteorological conditions, and their performance is evaluated by split sampling. The study area is located within the 112 km radius of Hannover radar in Lower Saxony, Germany and the data set constitutes of 80 recording stations in 5 min time steps. The results of this study reveal how the performance of the methods is affected by the adjustment of radar data, choice of merging method and selected event. Merging techniques can be used to improve the performance of online rainfall estimation, which gives way to the application of merging products in forecasting.

Cobalt sulfide aerogel prepared by anion exchange method with enhanced pseudocapacitive and water oxidation performances

Science.gov (United States)

Gao, Qiuyue; Shi, Zhenyu; Xue, Kaiming; Ye, Ziran; Hong, Zhanglian; Yu, Xinyao; Zhi, Mingjia

2018-05-01

This work introduces the anion exchange method into the sol-gel process for the first time to prepare a metal sulfide aerogel. A porous Co9S8 aerogel with a high surface area (274.2 m2 g‑1) and large pore volume (0.87 cm3 g‑1) has been successfully prepared by exchanging cobalt citrate wet gel in thioacetamide and subsequently drying in supercritical ethanol. Such a Co9S8 aerogel shows enhanced supercapacitive performance and catalytic activity toward oxygen evolution reaction (OER) compared to its oxide aerogel counterpart. High specific capacitance (950 F g‑1 at 1 A g‑1), good rate capability (74.3% capacitance retention from 1 to 20 A g‑1) and low onset overpotential for OER (220 mV) were observed. The results demonstrated here have implications in preparing various sulfide chalcogels.

A new method to calculate pressure drop and shell-side heat transfer coefficient in a shell-and-tube heat exchanger

International Nuclear Information System (INIS)

Baptista Filho, B.D.; Konuk, A.A.

1981-01-01

A new method to calculate pressure drop (Δp) and shell-side heat transfer coefficient (h sub(c)) in a shell-and-tube heat exchanger with segmental baffles is presented. The method is based on the solution of the equations of conservation of mass and momentum between two baffles. The calculated distributions of pressure and velocities given respectively, Δp and h sub(c). The values of Δp and h sub(c) are correlated for a given geometry whit the shell side fluid properties and flow rate. The calculated and experimental results agree very well for a U-Tube heat exchanger. (Author) [pt

Optimization of parameters of heat exchangers vehicles

Directory of Open Access Journals (Sweden)

Andrei MELEKHIN

2014-09-01

Full Text Available The relevance of the topic due to the decision of problems of the economy of resources in heating systems of vehicles. To solve this problem we have developed an integrated method of research, which allows to solve tasks on optimization of parameters of heat exchangers vehicles. This method decides multicriteria optimization problem with the program nonlinear optimization on the basis of software with the introduction of an array of temperatures obtained using thermography. The authors have developed a mathematical model of process of heat exchange in heat exchange surfaces of apparatuses with the solution of multicriteria optimization problem and check its adequacy to the experimental stand in the visualization of thermal fields, an optimal range of managed parameters influencing the process of heat exchange with minimal metal consumption and the maximum heat output fin heat exchanger, the regularities of heat exchange process with getting generalizing dependencies distribution of temperature on the heat-release surface of the heat exchanger vehicles, defined convergence of the results of research in the calculation on the basis of theoretical dependencies and solving mathematical model.

Methods to assess high-resolution subsurface gas concentrations and gas fluxes in wetland ecosystems

DEFF Research Database (Denmark)

Elberling, Bo; Kühl, Michael; Glud, Ronnie Nøhr

2013-01-01

The need for measurements of soil gas concentrations and surface fluxes of greenhouse gases at high temporal and spatial resolution in wetland ecosystem has lead to the introduction of several new analytical techniques and methods. In addition to the automated flux chamber methodology for high-re...

Potential for Small Unmanned Aircraft Systems Applications for Identifying Groundwater-Surface Water Exchange in a Meandering River Reach

Science.gov (United States)

Pai, H.; Malenda, H. F.; Briggs, M. A.; Singha, K.; González-Pinzón, R.; Gooseff, M. N.; Tyler, S. W.

2017-12-01

The exchange of groundwater and surface water (GW-SW), including dissolved constituents and energy, represents a critical yet challenging characterization problem for hydrogeologists and stream ecologists. Here we describe the use of a suite of high spatial resolution remote sensing techniques, collected using a small unmanned aircraft system (sUAS), to provide novel and complementary data to analyze GW-SW exchange. sUAS provided centimeter-scale resolution topography and water surface elevations, which are often drivers of exchange along the river corridor. Additionally, sUAS-based vegetation imagery, vegetation-top elevation, and normalized difference vegetation index mapping indicated GW-SW exchange patterns that are difficult to characterize from the land surface and may not be resolved from coarser satellite-based imagery. We combined these data with estimates of sediment hydraulic conductivity to provide a direct estimate of GW "shortcutting" through meander necks, which was corroborated by temperature data at the riverbed interface.

Study of time resolution by digital methods with a DRS4 module

Science.gov (United States)

Du, Cheng-Ming, Du; Jin-Da, Chen; Xiu-Ling, Zhang; Yang, Hai-Bo; Cheng, Ke; Kong, Jie; Hu, Zheng-Guo; Sun, Zhi-Yu; Su, Hong; Xu, Hu-Shan

2016-04-01

A new Digital Pulse Processing (DPP) module has been developed, based on a domino ring sampler version 4 chip (DRS4), with good time resolution for LaBr3 detectors, and different digital timing analysis methods for processing the raw detector signals are reported. The module, composed of an eight channel DRS4 chip, was used as the readout electronics and acquisition system to process the output signals from XP20D0 photomultiplier tubes (PMTs). Two PMTs were coupled with LaBr3 scintillators and placed on opposite sides of a radioactive positron 22Na source for 511 keV γ-ray tests. By analyzing the raw data acquired by the module, the best coincidence timing resolution is about 194.7 ps (FWHM), obtained by the digital constant fraction discrimination (dCFD) method, which is better than other digital methods and analysis methods based on conventional analog systems which have been tested. The results indicate that it is a promising approach to better localize the positron annihilation in positron emission tomography (PET) with time of flight (TOF), as well as for scintillation timing measurement, such as in TOF-ΔE and TOF-E systems for particle identification, with picosecond accuracy timing measurement. Furthermore, this module is more simple and convenient than other systems. Supported by the Science Foundation of the Chinese Academy of Sciences (210340XBO), National Natural Science Foundation of China (11305233,11205222), General Program of National Natural Science Foundation of China (11475234), Specific Fund of National Key Scientific Instrument and Equipment Development Project (2011YQ12009604) and Joint Fund for Research Based on Large-Scale Scientific Facilities (U1532131).

Developing bulk exchange spring magnets

Science.gov (United States)

Mccall, Scott K.; Kuntz, Joshua D.

2017-06-27

A method of making a bulk exchange spring magnet by providing a magnetically soft material, providing a hard magnetic material, and producing a composite of said magnetically soft material and said hard magnetic material to make the bulk exchange spring magnet. The step of producing a composite of magnetically soft material and hard magnetic material is accomplished by electrophoretic deposition of the magnetically soft material and the hard magnetic material to make the bulk exchange spring magnet.

Can Exchange Rates Be Predicted?

OpenAIRE

Siriwutiset, Trin

2007-01-01

Foreign exchange rates produce significant impacts on both the macroeconomic and microeconomic scale. Countries� government and multinational companies have been seeking ways to stabilize the exchange rates for a few decades. However, there is no perfect consensus on methods to control and stabilize the exchange rates. In fact, there are several occasions in history where turbulence movements caused crisis in the economies. There are several factors that are identified by economis...

An evaluation of solution algorithms and numerical approximation methods for modeling an ion exchange process

Science.gov (United States)

Bu, Sunyoung; Huang, Jingfang; Boyer, Treavor H.; Miller, Cass T.

2010-07-01

The focus of this work is on the modeling of an ion exchange process that occurs in drinking water treatment applications. The model formulation consists of a two-scale model in which a set of microscale diffusion equations representing ion exchange resin particles that vary in size and age are coupled through a boundary condition with a macroscopic ordinary differential equation (ODE), which represents the concentration of a species in a well-mixed reactor. We introduce a new age-averaged model (AAM) that averages all ion exchange particle ages for a given size particle to avoid the expensive Monte-Carlo simulation associated with previous modeling applications. We discuss two different numerical schemes to approximate both the original Monte-Carlo algorithm and the new AAM for this two-scale problem. The first scheme is based on the finite element formulation in space coupled with an existing backward difference formula-based ODE solver in time. The second scheme uses an integral equation based Krylov deferred correction (KDC) method and a fast elliptic solver (FES) for the resulting elliptic equations. Numerical results are presented to validate the new AAM algorithm, which is also shown to be more computationally efficient than the original Monte-Carlo algorithm. We also demonstrate that the higher order KDC scheme is more efficient than the traditional finite element solution approach and this advantage becomes increasingly important as the desired accuracy of the solution increases. We also discuss issues of smoothness, which affect the efficiency of the KDC-FES approach, and outline additional algorithmic changes that would further improve the efficiency of these developing methods for a wide range of applications.

Heat exchanger network retrofit optimization involving heat transfer enhancement

International Nuclear Information System (INIS)

Wang Yufei; Smith, Robin; Kim, Jin-Kuk

2012-01-01

Heat exchanger network retrofit plays an important role in energy saving in process industry. Many design methods for the retrofit of heat exchanger networks have been proposed during the last three decades. Conventional retrofit methods rely heavily on topology modifications which often result in a long retrofit duration and high initial costs. Moreover, the addition of extra surface area to the heat exchanger can prove difficult due to topology, safety and downtime constraints. Both of these problems can be avoided through the use of heat transfer enhancement in heat exchanger network retrofit. This paper presents a novel design approach to solve heat exchanger network retrofit problems based on heat transfer enhancement. An optimisation method based on simulated annealing has been developed to find the appropriate heat exchangers to be enhanced and to calculate the level of enhancement required. The physical insight of enhanced exchangers is also analysed. The new methodology allows several possible retrofit strategies using different retrofit methods be determined. Comparison of these retrofit strategies demonstrates that retrofit modification duration and payback time are reduced when heat transfer enhancement is utilised. Heat transfer enhancement can be also used as a substitute for increased heat exchanger network surface area to reduce retrofit investment costs.

Technical Note: Measuring contrast- and noise-dependent spatial resolution of an iterative reconstruction method in CT using ensemble averaging

Energy Technology Data Exchange (ETDEWEB)

Yu, Lifeng, E-mail: yu.lifeng@mayo.edu; Vrieze, Thomas J.; Leng, Shuai; Fletcher, Joel G.; McCollough, Cynthia H. [Department of Radiology, Mayo Clinic, Rochester, Minnesota 55905 (United States)

2015-05-15

Purpose: The spatial resolution of iterative reconstruction (IR) in computed tomography (CT) is contrast- and noise-dependent because of the nonlinear regularization. Due to the severe noise contamination, it is challenging to perform precise spatial-resolution measurements at very low-contrast levels. The purpose of this study was to measure the spatial resolution of a commercially available IR method using ensemble-averaged images acquired from repeated scans. Methods: A low-contrast phantom containing three rods (7, 14, and 21 HU below background) was scanned on a 128-slice CT scanner at three dose levels (CTDI{sub vol} = 16, 8, and 4 mGy). Images were reconstructed using two filtered-backprojection (FBP) kernels (B40 and B20) and a commercial IR method (sinogram affirmed iterative reconstruction, SAFIRE, Siemens Healthcare) with two strength settings (I40-3 and I40-5). The same scan was repeated 100 times at each dose level. The modulation transfer function (MTF) was calculated based on the edge profile measured on the ensemble-averaged images. Results: The spatial resolution of the two FBP kernels, B40 and B20, remained relatively constant across contrast and dose levels. However, the spatial resolution of the two IR kernels degraded relative to FBP as contrast or dose level decreased. For a given dose level at 16 mGy, the MTF{sub 50%} value normalized to the B40 kernel decreased from 98.4% at 21 HU to 88.5% at 7 HU for I40-3 and from 97.6% to 82.1% for I40-5. At 21 HU, the relative MTF{sub 50%} value decreased from 98.4% at 16 mGy to 90.7% at 4 mGy for I40-3 and from 97.6% to 85.6% for I40-5. Conclusions: A simple technique using ensemble averaging from repeated CT scans can be used to measure the spatial resolution of IR techniques in CT at very low contrast levels. The evaluated IR method degraded the spatial resolution at low contrast and high noise levels.

[TVT (transvaginal mesh) surgical method for complex resolution of pelvic floor defects].

Science.gov (United States)

Adamík, Z

2006-01-01

Assessment of the effects of a new surgical method for complex resolution of pelvic floor defects. Case study. Department of Obstetrics and Gynaecology, Bata Hospital, Zlín. We evaluated the procedures and results of the new TVM (transvaginal mesh) surgical method which we used in a group of 12 patients. Ten patients had vaginal prolapse following vaginal hysterectomy and in two cases there was uterine prolapse and vaginal prolapse. Only in one case there was a small protrusion in the range of 0.5 cm which we resolved by removal of the penetrated section. The resulting anatomic effect was very good in all the cases.

A new method for high-resolution characterization of hydraulic conductivity

Science.gov (United States)

Liu, Gaisheng; Butler, J.J.; Bohling, Geoffrey C.; Reboulet, Ed; Knobbe, Steve; Hyndman, D.W.

2009-01-01

A new probe has been developed for high-resolution characterization of hydraulic conductivity (K) in shallow unconsolidated formations. The probe was recently applied at the Macrodispersion Experiment (MADE) site in Mississippi where K was rapidly characterized at a resolution as fine as 0.015 m, which has not previously been possible. Eleven profiles were obtained with K varying up to 7 orders of magnitude in individual profiles. Currently, high-resolution (0.015-m) profiling has an upper K limit of 10 m/d; lower-resolution (???0.4-m) mode is used in more permeable zones pending modifications. The probe presents a new means to help address unresolved issues of solute transport in heterogeneous systems. Copyright 2009 by the American Geophysical Union.

Application of the finite element method to problems with heat radiation exchange

International Nuclear Information System (INIS)

Breitbach, G.; Altes, J.

1985-07-01

The calculation of temperature distributions for systems exchanging heat radiation requires in a first step the determination of the heat fluxes caused by radiation at its surfaces. In this paper the radiation transport equation is developed and it is shown, that it can be derived from a variational principle. The functional of the variational principle is the starting point of a numerical solution method. By using Finite Element Procedures a system of linear equations is derived, which supplies an approximation of the radiosity. Having the radiosity the heat flux at the surfaces, which governs as the boundary condition the temperature distribution in the structure, can be calculated. (orig.) [de

Simultaneous super-resolution and blind deconvolution

International Nuclear Information System (INIS)

Sroubek, F; Flusser, J; Cristobal, G

2008-01-01

In many real applications, blur in input low-resolution images is a nuisance, which prevents traditional super-resolution methods from working correctly. This paper presents a unifying approach to the blind deconvolution and superresolution problem of multiple degraded low-resolution frames of the original scene. We introduce a method which assumes no prior information about the shape of degradation blurs and which is properly defined for any rational (fractional) resolution factor. The method minimizes a regularized energy function with respect to the high-resolution image and blurs, where regularization is carried out in both the image and blur domains. The blur regularization is based on a generalized multichannel blind deconvolution constraint. Experiments on real data illustrate robustness and utilization of the method

The Brazilian dilution method for ballast water exchange; O metodo de diluicao brasileiro para troca de agua de lastro

Energy Technology Data Exchange (ETDEWEB)

Mauro, Celso Alleluia [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas. Avaliacao e Monitoramento Ambiental]. E-mail: celso@cenpes.petrobras.com.br; Land, Claudio Goncalves [PETROBRAS, Rio de Janeiro, RJ (Brazil). Abastecimento, Logistica e Planejamento]. E-mail: cgland@petrobras.com.br; Pimenta, Jose Maria Hollanda Alvares; Barreto, Francisco Carlos Peixoto [PETROBRAS, Rio de Janeiro, RJ (Brazil). Engenharia; Brandao, Marcus Vinicius Lisboa; Marroig, Nilton Lemos [Transpetro, Rio de Janeiro, RJ (Brazil). Frota Nacional de Petroleiros. Inspetoria Geral; Tristao, Maria Luiza Braganca [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas. Quimica; Fadel, Andre Luiz da Fonseca [PETROBRAS, Rio de Janeiro, RJ (Brazil). Financas Corporativa e Tesouraria; Villac, Maria Celia; Fernandes, Lohengrin; Paranhos, Rodolfo; Dias, Cristina; Bonecker, Sergio; Denise Tenenbaum [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Biologia; Persich, Graziela; Garcia, Virginia; Odebrecht, Clarisse [Fundacao Universidade do Rio Grande, RS (Brazil). Dept. de Oceanografia

2002-12-01

In a precautionary approach and dealing with the coming International Maritime Organization (IMO) regulations on ballast water, PETROBRAS developed a new method for ballast water exchange in tankers. Differently from ordinary methods PETROBRAS method which have been called Brazilian Dilution Method (BDM) or Dilution Method involves ballast loading through the top with simultaneous unloading from the bottom of the tanks. The method proposal was firstly presented to IMO, which encouraged PETROBRAS to carry out a field trial. PETROBRAS in June 1998 carried out a trial in the product carrier M/V Lavras. A simulation study was useful to plan the trial assessing the theoretical efficiency of the method, establishing the best sampling points and comparing the BDM with the Tank Overfilling Method (TOM). Simulation showed that for the same tank shape, the water renewal in BDM is more effective than in TOM and that 90 % of water renewal could be obtained by BDM. A dye concentration variation monitoring and a biological assessment were performed and the results confirmed that over than 90 % of the ballast water was renewed after three exchanges. The method was proved safe, practical, economical and suitable to minimize the risk of exotic species transport between ports. (author)

Ion exchange behaviour of citrate and EDTA anions on strong and weak base organic ion exchangers

International Nuclear Information System (INIS)

Askarieh, M.M.; White, D.A.

1988-01-01

The exchange of citrate and EDTA ions with two strong base and two weak base exchangers is considered. Citrate and EDTA analysis for this work was performed using a colorimetric method developed here. The ions most selectively exchanged on the resins are H 2 cit - and H 2 EDTA 2- , though EDTA is generally less strongly sorbed on strong base resins. In contact with weak base resins, deprotonation of the resin occurs during ion exchange with a noticeable drop in solution pH. Although EDTA sorption can be reversed by nitric acid, citrate ions are significantly held on the resin at low pH. The exchange of citrate can be made reversible if bicarbonate is added to the initial solutions. Alkaline regeneration of exchangers loaded with EDTA proved to be very effective. (author)

High resolution imaging of vadose zone transport using crosswell radar and seismic methods; TOPICAL

International Nuclear Information System (INIS)

Majer, Ernest L.; Williams, Kenneth H.; Peterson, John E.; Daley, Thomas E.

2001-01-01

The summary and conclusions are that overall the radar and seismic results were excellent. At the time of design of the experiments we did not know how well these two methods could penetrate or resolve the moisture content and structure. It appears that the radar could easily go up to 5, even 10 meters between boreholes at 200 Mhz and even father (up to 20 to 40 m) at 50 Mhz. The seismic results indicate that at several hundred hertz propagation of 20 to 30 meters giving high resolution is possible. One of the most important results, however is that together the seismic and radar are complementary in their properties estimation. The radar being primarily sensitive to changes in moisture content, and the seismic being primarily sensitive to porosity. Taken in a time lapse sense the radar can show the moisture content changes to a high resolution, with the seismic showing high resolution lithology. The significant results for each method are: Radar: (1) Delineated geological layers 0.25 to 3.5 meters thick with 0.25 m resolution; (2) Delineated moisture movement and content with 0.25 m resolution; (3) Compared favorably with neutron probe measurements; and (4) Penetration up to 30 m. Radar results indicate that the transport of the riverwater is different from that of the heavier and more viscous sodium thiosulfate. It appears that the heavier fluids are not mixing readily with the in-situ fluids and the transport may be influenced by them. Seismic: (1) Delineated lithology at .25 m resolution; (2) Penetration over 20 meters, with a possibility of up to 30 or more meters; and (3) Maps porosity and density differences of the sediments. Overall the seismic is mapping the porosity and density distribution. The results are consistent with the flow field mapped by the radar, there is a change in flow properties at the 10 to 11 meter depth in the flow cell. There also appears to be break through by looking at the radar data with the denser sodium thiosulfate finally

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.

High resolution neutron spectroscopy - a tool for the investigation of dynamics of polymers and soft matter

International Nuclear Information System (INIS)

Monkenbusch, M.; Richter, D.

2007-01-01

Neutron scattering, with the ability to vary the contrast of molecular items by hydrogen/deuterium exchanges, is an invaluable tool for soft matter research. Besides the structural information on the mesoscopic scale that is obtained by diffraction methods like small angle neutron scattering, the slow dynamics of molecular motion on mesoscopic scale is accessible by high resolution neutron spectroscopy. The basic features of neutron backscattering spectroscopy, and in particular neutron spin-echo spectroscopy, are presented, in combination with illustrations of results from polymer melt dynamics to protein dynamics which are obtained by these techniques. (authors)

Effective exchange potentials for electronically inelastic scattering

International Nuclear Information System (INIS)

Schwenke, D.W.; Staszewska, G.; Truhlar, D.G.

1983-01-01

We propose new methods for solving the electron scattering close coupling equations employing equivalent local exchange potentials in place of the continuum-multiconfiguration-Hartree--Fock-type exchange kernels. The local exchange potentials are Hermitian. They have the correct symmetry for any symmetries of excited electronic states included in the close coupling expansion, and they have the same limit at very high energy as previously employed exchange potentials. Comparison of numerical calculations employing the new exchange potentials with the results obtained with the standard nonlocal exchange kernels shows that the new exchange potentials are more accurate than the local exchange approximations previously available for electronically inelastic scattering. We anticipate that the new approximations will be most useful for intermediate-energy electronically inelastic electron--molecule scattering

Applications of high-resolution spatial discretization scheme and Jacobian-free Newton–Krylov method in two-phase flow problems

International Nuclear Information System (INIS)

Zou, Ling; Zhao, Haihua; Zhang, Hongbin

2015-01-01

Highlights: • Using high-resolution spatial scheme in solving two-phase flow problems. • Fully implicit time integrations scheme. • Jacobian-free Newton–Krylov method. • Analytical solution for two-phase water faucet problem. - Abstract: The majority of the existing reactor system analysis codes were developed using low-order numerical schemes in both space and time. In many nuclear thermal–hydraulics applications, it is desirable to use higher-order numerical schemes to reduce numerical errors. High-resolution spatial discretization schemes provide high order spatial accuracy in smooth regions and capture sharp spatial discontinuity without nonphysical spatial oscillations. In this work, we adapted an existing high-resolution spatial discretization scheme on staggered grids in two-phase flow applications. Fully implicit time integration schemes were also implemented to reduce numerical errors from operator-splitting types of time integration schemes. The resulting nonlinear system has been successfully solved using the Jacobian-free Newton–Krylov (JFNK) method. The high-resolution spatial discretization and high-order fully implicit time integration numerical schemes were tested and numerically verified for several two-phase test problems, including a two-phase advection problem, a two-phase advection with phase appearance/disappearance problem, and the water faucet problem. Numerical results clearly demonstrated the advantages of using such high-resolution spatial and high-order temporal numerical schemes to significantly reduce numerical diffusion and therefore improve accuracy. Our study also demonstrated that the JFNK method is stable and robust in solving two-phase flow problems, even when phase appearance/disappearance exists

Effect of ADS-B Characteristics on Airborne Conflict Detection and Resolution

NARCIS (Netherlands)

Langejan, T.P.; Sunil, E.; Ellerbroek, J.; Hoekstra, J.M.

2016-01-01

Most Free-Flight concepts rely on self-separation by means of airborne Conflict Detection and Resolution (CD&R) algorithms. A key enabling technology for airborne CD&R is the Automatic Dependent Surveillance-Broadcast (ADS-B) system, which is used for direct state information exchange

Use of a New High Resolution Melting Method for Genotyping Pathogenic Leptospira spp.

Directory of Open Access Journals (Sweden)

Florence Naze

Full Text Available Leptospirosis is a worldwide zoonosis that is endemic in tropical areas, such as Reunion Island. The species Leptospira interrogans is the primary agent in human infections, but other pathogenic species, such as L. kirschner and L. borgpetersenii, are also associated with human leptospirosis.In this study, a melting curve analysis of the products that were amplified with the primer pairs lfb1 F/R and G1/G2 facilitated an accurate species classification of Leptospira reference strains. Next, we combined an unsupervised high resolution melting (HRM method with a new statistical approach using primers to amplify a two variable-number tandem-repeat (VNTR for typing at the subspecies level. The HRM analysis, which was performed with ScreenClust Software, enabled the identification of genotypes at the serovar level with high resolution power (Hunter-Gaston index 0.984. This method was also applied to Leptospira DNA from blood samples that were obtained from Reunion Island after 1998. We were able to identify a unique genotype that is identical to that of the L. interrogans serovars Copenhageni and Icterohaemorrhagiae, suggesting that this genotype is the major cause of leptospirosis on Reunion Island.Our simple, rapid, and robust genotyping method enables the identification of Leptospira strains at the species and subspecies levels and supports the direct genotyping of Leptospira in biological samples without requiring cultures.

Sediment Core Extrusion Method at Millimeter Resolution Using a Calibrated, Threaded-rod.

Science.gov (United States)

Schwing, Patrick T; Romero, Isabel C; Larson, Rebekka A; O'Malley, Bryan J; Fridrik, Erika E; Goddard, Ethan A; Brooks, Gregg R; Hastings, David W; Rosenheim, Brad E; Hollander, David J; Grant, Guy; Mulhollan, Jim

2016-08-17

Aquatic sediment core subsampling is commonly performed at cm or half-cm resolution. Depending on the sedimentation rate and depositional environment, this resolution provides records at the annual to decadal scale, at best. An extrusion method, using a calibrated, threaded-rod is presented here, which allows for millimeter-scale subsampling of aquatic sediment cores of varying diameters. Millimeter scale subsampling allows for sub-annual to monthly analysis of the sedimentary record, an order of magnitude higher than typical sampling schemes. The extruder consists of a 2 m aluminum frame and base, two core tube clamps, a threaded-rod, and a 1 m piston. The sediment core is placed above the piston and clamped to the frame. An acrylic sampling collar is affixed to the upper 5 cm of the core tube and provides a platform from which to extract sub-samples. The piston is rotated around the threaded-rod at calibrated intervals and gently pushes the sediment out the top of the core tube. The sediment is then isolated into the sampling collar and placed into an appropriate sampling vessel (e.g., jar or bag). This method also preserves the unconsolidated samples (i.e., high pore water content) at the surface, providing a consistent sampling volume. This mm scale extrusion method was applied to cores collected in the northern Gulf of Mexico following the Deepwater Horizon submarine oil release. Evidence suggests that it is necessary to sample at the mm scale to fully characterize events that occur on the monthly time-scale for continental slope sediments.

High Resolution DNS of Turbulent Flows using an Adaptive, Finite Volume Method

Science.gov (United States)

Trebotich, David

2014-11-01

We present a new computational capability for high resolution simulation of incompressible viscous flows. Our approach is based on cut cell methods where an irregular geometry such as a bluff body is intersected with a rectangular Cartesian grid resulting in cut cells near the boundary. In the cut cells we use a conservative discretization based on a discrete form of the divergence theorem to approximate fluxes for elliptic and hyperbolic terms in the Navier-Stokes equations. Away from the boundary the method reduces to a finite difference method. The algorithm is implemented in the Chombo software framework which supports adaptive mesh refinement and massively parallel computations. The code is scalable to 200,000 + processor cores on DOE supercomputers, resulting in DNS studies at unprecedented scale and resolution. For flow past a cylinder in transition (Re = 300) we observe a number of secondary structures in the far wake in 2D where the wake is over 120 cylinder diameters in length. These are compared with the more regularized wake structures in 3D at the same scale. For flow past a sphere (Re = 600) we resolve an arrowhead structure in the velocity in the near wake. The effectiveness of AMR is further highlighted in a simulation of turbulent flow (Re = 6000) in the contraction of an oil well blowout preventer. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Advanced Scientific Computing Research, Applied Mathematics program under Contract Number DE-AC02-05-CH11231.

Analysis of radiation-natural convection interactions in 1-G and low-G environments using the discrete exchange factor method

International Nuclear Information System (INIS)

Kassemi, M.

1990-01-01

In this paper a new numerical method is presented for the analysis of combined natural convection and radiation heat transfer which has application in many engineering situations such as materials processing, combustion and fire research. Because of the recent interest in the performance of these engineering processes in the low-gravity environment of space, attention is devoted to both 1-g and low-g applications. The numerical study is based on a two-dimensional mathematical model represented by a set of coupled nonlinear partial differential equations for conservation of mass, momentum, and energy and the integro-differential equations which describe radiative heat transfer. Radiative exchange is formulated using the discrete exchange factor method (DEF). This method considers point to point exchange and provides accurate results over a wide range of radiation parameters. The desirable features of DEF are briefly described. Our numerical results show that radiation significantly influences the flow and heat transfer in the enclosure. In both low-g and 1-g applications, radiation modifies the temperature profiles and enhances the convective heat transfer at the cold wall. In a low-g environment, convection is weak, and radiation can easily become the dominant heat transfer mode. It is also shown that in the top-heated enclosure, volumetric heating by radiation gives rise to an intricate cell pattern in the cavity

Probes for inspections of heat exchanges installed at nuclear power plants type PWR by eddy current method

International Nuclear Information System (INIS)

Silva, Alonso F.O.

2007-01-01

From all non destructive examination methods usable to perform integrity evaluation of critical equipment installed at nuclear power plants (NPP), eddy current test (ET) may be considered the most important one, when examining heat exchangers. For its application, special probes and reference calibration standards are employed. In pressurized water reactor (PWR) NPPs, a particularly critical equipment is the steam generator (SG), a huge heat exchanger that contains thousands of U-bend thin wall tubes. Due to its severe working conditions (pressure and temperature), that component is periodically examined by means of ET. In this paper a revision of the operating fundamentals of the main ET probes, used to perform SG inspections is presented. (author)

High resolution through-the-wall radar image based on beamspace eigenstructure subspace methods

Science.gov (United States)

Yoon, Yeo-Sun; Amin, Moeness G.

2008-04-01

Through-the-wall imaging (TWI) is a challenging problem, even if the wall parameters and characteristics are known to the system operator. Proper target classification and correct imaging interpretation require the application of high resolution techniques using limited array size. In inverse synthetic aperture radar (ISAR), signal subspace methods such as Multiple Signal Classification (MUSIC) are used to obtain high resolution imaging. In this paper, we adopt signal subspace methods and apply them to the 2-D spectrum obtained from the delay-andsum beamforming image. This is in contrast to ISAR, where raw data, in frequency and angle, is directly used to form the estimate of the covariance matrix and array response vector. Using beams rather than raw data has two main advantages, namely, it improves the signal-to-noise ratio (SNR) and can correctly image typical indoor extended targets, such as tables and cabinets, as well as point targets. The paper presents both simulated and experimental results using synthesized and real data. It compares the performance of beam-space MUSIC and Capon beamformer. The experimental data is collected at the test facility in the Radar Imaging Laboratory, Villanova University.

Inverse transformation algorithm of transient electromagnetic field and its high-resolution continuous imaging interpretation method

International Nuclear Information System (INIS)

Qi, Zhipeng; Li, Xiu; Lu, Xushan; Zhang, Yingying; Yao, Weihua

2015-01-01

We introduce a new and potentially useful method for wave field inverse transformation and its application in transient electromagnetic method (TEM) 3D interpretation. The diffusive EM field is known to have a unique integral representation in terms of a fictitious wave field that satisfies a wave equation. The continuous imaging of TEM can be accomplished using the imaging methods in seismic interpretation after the diffusion equation is transformed into a fictitious wave equation. The interpretation method based on the imaging of a fictitious wave field could be used as a fast 3D inversion method. Moreover, the fictitious wave field possesses some wave field features making it possible for the application of a wave field interpretation method in TEM to improve the prospecting resolution.Wave field transformation is a key issue in the migration imaging of a fictitious wave field. The equation in the wave field transformation belongs to the first class Fredholm integration equation, which is a typical ill-posed equation. Additionally, TEM has a large dynamic time range, which also facilitates the weakness of this ill-posed problem. The wave field transformation is implemented by using pre-conditioned regularized conjugate gradient method. The continuous imaging of a fictitious wave field is implemented by using Kirchhoff integration. A synthetic aperture and deconvolution algorithm is also introduced to improve the interpretation resolution. We interpreted field data by the method proposed in this paper, and obtained a satisfying interpretation result. (paper)

Platform dependencies in bottom-up hydrogen/deuterium exchange mass spectrometry.

Science.gov (United States)

Burns, Kyle M; Rey, Martial; Baker, Charles A H; Schriemer, David C

2013-02-01

Hydrogen-deuterium exchange mass spectrometry is an important method for protein structure-function analysis. The bottom-up approach uses protein digestion to localize deuteration to higher resolution, and the essential measurement involves centroid mass determinations on a very large set of peptides. In the course of evaluating systems for various projects, we established two (HDX-MS) platforms that consisted of a FT-MS and a high-resolution QTOF mass spectrometer, each with matched front-end fluidic systems. Digests of proteins spanning a 20-110 kDa range were deuterated to equilibrium, and figures-of-merit for a typical bottom-up (HDX-MS) experiment were compared for each platform. The Orbitrap Velos identified 64% more peptides than the 5600 QTOF, with a 42% overlap between the two systems, independent of protein size. Precision in deuterium measurements using the Orbitrap marginally exceeded that of the QTOF, depending on the Orbitrap resolution setting. However, the unique nature of FT-MS data generates situations where deuteration measurements can be inaccurate, because of destructive interference arising from mismatches in elemental mass defects. This is shown through the analysis of the peptides common to both platforms, where deuteration values can be as low as 35% of the expected values, depending on FT-MS resolution, peptide length and charge state. These findings are supported by simulations of Orbitrap transients, and highlight that caution should be exercised in deriving centroid mass values from FT transients that do not support baseline separation of the full isotopic composition.

Studies on inorganic exchanger: zirconium antimonate

International Nuclear Information System (INIS)

Dash, A.; Balasubramanian, K.R.

1992-01-01

The inorganic exchanger zirconium antimonate has been prepared and its characteristics evaluated. A method has been developed for the separation of 90 Sr and 144 Ce from fission products solution using this exchanger. (author). 23 refs., 18 f igs., 9 tabs

Is high-resolution inverse characterization of heterogeneous river bed hydraulic conductivities needed and possible?

Directory of Open Access Journals (Sweden)

W. Kurtz

2013-10-01

Full Text Available River–aquifer exchange fluxes influence local and regional water balances and affect groundwater and river water quality and quantity. Unfortunately, river–aquifer exchange fluxes tend to be strongly spatially variable, and it is an open research question to which degree river bed heterogeneity has to be represented in a model in order to achieve reliable estimates of river–aquifer exchange fluxes. This research question is addressed in this paper with the help of synthetic simulation experiments, which mimic the Limmat aquifer in Zurich (Switzerland, where river–aquifer exchange fluxes and groundwater management activities play an important role. The solution of the unsaturated–saturated subsurface hydrological flow problem including river–aquifer interaction is calculated for ten different synthetic realities where the strongly heterogeneous river bed hydraulic conductivities (L are perfectly known. Hydraulic head data (100 in the default scenario are sampled from the synthetic realities. In subsequent data assimilation experiments, where L is unknown now, the hydraulic head data are used as conditioning information, with the help of the ensemble Kalman filter (EnKF. For each of the ten synthetic realities, four different ensembles of L are tested in the experiments with EnKF; one ensemble estimates high-resolution L fields with different L values for each element, and the other three ensembles estimate effective L values for 5, 3 or 2 zones. The calibration of higher-resolution L fields (i.e. fully heterogeneous or 5 zones gives better results than the calibration of L for only 3 or 2 zones in terms of reproduction of states, stream–aquifer exchange fluxes and parameters. Effective L for a limited number of zones cannot always reproduce the true states and fluxes well and results in biased estimates of net exchange fluxes between aquifer and stream. Also in case only 10 head data are used for conditioning, the high-resolution

Comprehensive analysis of pharmaceutical products using simultaneous mixed-mode (ion-exchange/reversed-phase) and hydrophilic interaction liquid chromatography.

Science.gov (United States)

Kazarian, Artaches A; Nesterenko, Pavel N; Soisungnoen, Phimpha; Burakham, Rodjana; Srijaranai, Supalax; Paull, Brett

2014-08-01

Liquid chromatographic assays were developed using a mixed-mode column coupled in sequence with a hydrophilic interaction liquid chromatography column to allow the simultaneous comprehensive analysis of inorganic/organic anions and cations, active pharmaceutical ingredients, and excipients (carbohydrates). The approach utilized dual sample injection and valve-mediated column switching and was based upon a single high-performance liquid chromatography gradient pump. The separation consisted of three distinct sequential separation mechanisms, namely, (i) ion-exchange, (ii) mixed-mode interactions under an applied dual gradient (reversed-phase/ion-exchange), and (iii) hydrophilic interaction chromatography. Upon first injection, the Scherzo SS C18 column (Imtakt) provided resolution of inorganic anions and cations under isocratic conditions, followed by a dual organic/salt gradient to elute active pharmaceutical ingredients and their respective organic counterions and potential degradants. At the top of the mixed-mode gradient (high acetonitrile content), the mobile phase flow was switched to a preconditioned hydrophilic interaction liquid chromatography column, and the standard/sample was reinjected for the separation of hydrophilic carbohydrates, some of which are commonly known excipients in drug formulations. The approach afforded reproducible separation and resolution of up to 23 chemically diverse solutes in a single run. The method was applied to investigate the composition of commercial cough syrups (Robitussin®), allowing resolution and determination of inorganic ions, active pharmaceutical ingredients, excipients, and numerous well-resolved unknown peaks. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Relationship between indoor radon concentrations and air exchange rate

International Nuclear Information System (INIS)

Wang Jingshu; Liu Yuyu; Yao Xiaohua; Meng Jianfeng; Zhang Yongyi; Wang Xiaohe; Yu Xiufen.

1995-01-01

The indoor concentration of radon and the air exchange rate were simultaneously measured in four empty rooms, made of brick and cement, which were located in different floors of dwelling houses in Taiyuan, Shanxi, China. SF 6 tracer gas decay method was used to measure the air exchange rate. Indoor radon was collected with the dimembrane method. When the ventilation rate increased, the concentration of radon dropped rapidly. Regression analysis indicated that the indoor concentration of radon was equal to the outdoor level of radon when the air exchange rate was greater than 3-4. SF 6 decay method was an effective and convenient method for measuring the air exchange rate. There was no marked difference in measurements obtained in different locations of a room. (N.K.)

A VIRTUAL GLOBE-BASED MULTI-RESOLUTION TIN SURFACE MODELING AND VISUALIZETION METHOD

Directory of Open Access Journals (Sweden)

X. Zheng

2016-06-01

Full Text Available The integration and visualization of geospatial data on a virtual globe play an significant role in understanding and analysis of the Earth surface processes. However, the current virtual globes always sacrifice the accuracy to ensure the efficiency for global data processing and visualization, which devalue their functionality for scientific applications. In this article, we propose a high-accuracy multi-resolution TIN pyramid construction and visualization method for virtual globe. Firstly, we introduce the cartographic principles to formulize the level of detail (LOD generation so that the TIN model in each layer is controlled with a data quality standard. A maximum z-tolerance algorithm is then used to iteratively construct the multi-resolution TIN pyramid. Moreover, the extracted landscape features are incorporated into each-layer TIN, thus preserving the topological structure of terrain surface at different levels. In the proposed framework, a virtual node (VN-based approach is developed to seamlessly partition and discretize each triangulation layer into tiles, which can be organized and stored with a global quad-tree index. Finally, the real time out-of-core spherical terrain rendering is realized on a virtual globe system VirtualWorld1.0. The experimental results showed that the proposed method can achieve an high-fidelity terrain representation, while produce a high quality underlying data that satisfies the demand for scientific analysis.

On the Effect of Clamping Pressure and Method on the Current Mapping of Proton Exchange Membrane Water Electrolysis

DEFF Research Database (Denmark)

Al Shakhshir, Saher; Zhou, Fan; Kær, Søren Knudsen

The degradation of the electrochemical reaction of the proton exchange membrane water electrolysis (PEMWE) can be characterized using in-situ current mapping measurements (CMM). CMM is significantly affected by the amount of clamping pressure and method. In this work the current is mapped...

Argentina's experience with parallel exchange markets: 1981-1990

OpenAIRE

Steven B. Kamin

1991-01-01

This paper surveys the development and operation of the parallel exchange market in Argentina during the 1980s, and evaluates its impact upon macroeconomic performance and policy. The historical evolution of Argentina's exchange market policies is reviewed in order to understand the government's motives for imposing exchange controls. The parallel exchange market engendered by these controls is then analyzed, and econometric methods are used to evaluate the behavior of the parallel exchange r...

Exchange-correlation energy in the orbital occupancy method: electronic structure of organic molecules

International Nuclear Information System (INIS)

Oszwaldowski, R; Vazquez, H; Pou, P; Ortega, J; Perez, R; Flores, F

2003-01-01

A new DF-LCAO (density functional with local combination of atomic orbitals) method is used to calculate the electronic properties of 3,4,9,10 perylenetetracarboxylic dianhydride (PTCDA), C 6 H 6 , CH 4 , and CO. The method, called the OO (orbital occupancy) method, is a DF-based theory, which uses the OOs instead of ρ(r) to calculate the exchange and correlation energies. In our calculations, we compare the OO method with the conventional local density approximation approach. Our results show that, using a minimal basis set, we obtain equilibrium bond lengths and binding energies for PTCDA, C 6 H 6 , and CH 4 which are respectively within 6, and 10-15% of the experimental values. We have also calculated the affinity and ionization levels, as well as the optical gap, for benzene and PTCDA and have found that a variant of Koopmans' theorem works well for these molecules. Using this theorem we calculate the Koopmans relaxation energies of the σ- and π-orbitals for PTCDA and have obtained this molecule's density of states which compares well with experimental evidence

Heat exchanger tube inspection using ultrasonic arrays

International Nuclear Information System (INIS)

Meyer, P.A.; Carodiskey, T.J.

1986-01-01

Tubing used in industrial heat exchangers is often subject to failure caused by corrosion and cracking. Technical conferences are used as a forum in the steam generator industry to ensure that the failure mechanisms are well understood and that the quality of the heat exchanger is maintained. The quality of a heat exchanger can be thought of as its ability to operate to design specifications over its intended life. This is the motivation to inspect and evaluate these devices periodically. Inspection, however, normally requires shutdown of the heat exchanger which is costly but is much more acceptable than an unscheduled shutdown due to failure of a tube. Therefore, the degree of inspection is established by balancing the cost of inspection with the risk of a tube failure. Any method of reducing the cost of inspection will permit a higher degree of inspection and, therefore, improve heat exchanger quality. This paper reviews the design and performance of an improved method of ultrasonic inspection of heat exchanger tubing with emphasis on applications in the nuclear industry

Novel Method for Exchange of Impella Circulatory Assist Catheter: The "Trojan Horse" Technique.

Science.gov (United States)

Phillips, Colin T; Tamez, Hector; Tu, Thomas M; Yeh, Robert W; Pinto, Duane S

2017-07-01

Patients with an indwelling Impella may require escalation of hemodynamic support or exchange to another circulatory assistance platform. As such, preservation of vascular access is preferable in cases where anticoagulation cannot be discontinued or to facilitate exchange to an alternative catheter or closure device. Challenges exist in avoiding bleeding and loss of wire access in these situations. We describe a single-access "Trojan Horse" technique that minimizes bleeding while maintaining arterial access for rapid exchange of this percutaneous ventricular assist device.

Rapid ion-exchange separations of actinides

International Nuclear Information System (INIS)

Usuda, Shigekazu

1988-01-01

For the purpose of studying short-lived actinide nuclides, three methods for rapid ion exchange separation of actinide elements with mineral acid-alcohol mixed media were developed: anion exchange with nitric acid-methyl alcohol mixed media to separate the transplutonium and rare earth elements from target material, U or Pu and Al catcher foils; anion exchange with hydrochloric acid-methyl alcohol media to separate Am+Cm, Bk and Cf+Fm from the target, catcher foils and major fission products; and cation exchange with hydrochloric acid-methyl alcohol media and with concentrated hydrochloric acid to separate the transplutonium elements as a group from the rare earths after eliminating the large amounts of U, Al, Cu, Fe etc. The methods enable one to perform rapid and effective separation at elevated temperature (90 deg C) and immediate source preparation for alpha-ray spectrometry. (author) 47 refs.; 10 figs

Measurement of liquid mixing characteristics in large-sized ion exchange column for isotope separation by stepwise response method

International Nuclear Information System (INIS)

Fujine, Sachio; Saito, Keiichiro; Iwamoto, Kazumi; Itoi, Toshiaki.

1981-07-01

Liquid mixing in a large-sized ion exchange column for isotope separation was measured by the step-wise response method, using NaCl solution as tracer. A 50 cm diameter column was packed with an ion exchange resin of 200 μm in mean diameter. Experiments were carried out for several types of distributor and collector, which were attached to each end of the column. The smallest mixing was observed for the perforated plate type of the collector, coupled with a minimum stagnant volume above the ion exchange resin bed. The 50 cm diameter column exhibited the better characteristics of liquid mixing than the 2 cm diameter column for which the good performance of lithium isotope separation had already been confirmed. These results indicate that a large increment of throughput is attainable by the scale-up of column diameter with the same performance of isotope separation as for the 2 cm diameter column. (author)

Example-Based Super-Resolution Fluorescence Microscopy.

Science.gov (United States)

Jia, Shu; Han, Boran; Kutz, J Nathan

2018-04-23

Capturing biological dynamics with high spatiotemporal resolution demands the advancement in imaging technologies. Super-resolution fluorescence microscopy offers spatial resolution surpassing the diffraction limit to resolve near-molecular-level details. While various strategies have been reported to improve the temporal resolution of super-resolution imaging, all super-resolution techniques are still fundamentally limited by the trade-off associated with the longer image acquisition time that is needed to achieve higher spatial information. Here, we demonstrated an example-based, computational method that aims to obtain super-resolution images using conventional imaging without increasing the imaging time. With a low-resolution image input, the method provides an estimate of its super-resolution image based on an example database that contains super- and low-resolution image pairs of biological structures of interest. The computational imaging of cellular microtubules agrees approximately with the experimental super-resolution STORM results. This new approach may offer potential improvements in temporal resolution for experimental super-resolution fluorescence microscopy and provide a new path for large-data aided biomedical imaging.

Application of ion exchangers

International Nuclear Information System (INIS)

Markhol, M.

1985-01-01

Existing methods of multi-element separation for radiochemical analysis are considered. The majority of existing methods is noted to be based on application of organic and inorganic ion exchangers. Distillation, coprecipitation, extraction as well as combination of the above methods are also used. Concrete flowsheets of multi-element separation are presented

Gas exchange measurements in natural systems

International Nuclear Information System (INIS)

Broecker, W.S.; Peng, T.H.

1983-01-01

Direct knowledge of the rates of gas exchange in lakes and the ocean is based almost entirely on measurements of the isotopes 14 C, 222 Rn and 3 He. The distribution of natural radiocarbon has yielded the average rate of CO 2 exchange for the ocean and for several closed basin lakes. That of bomb produced radiocarbon has been used in the same systems. The 222 Rn to 226 Ra ratio in open ocean surface water has been used to give local short term gas exchange rates. The radon method generally cannot be used in lakes, rivers, estuaries or shelf areas because of the input of radon from sediments. A few attempts have been made to use the excess 3 He produced by decay of bomb produced tritium in lakes to give gas transfer rates. The uncertainty in the molecular diffusivity of helium and in the diffusivity dependence of the rate of gas transfer holds back the application of this method. A few attempts have been made to enrich the surface waters of small lakes with 226 Ra and 3 H in order to allow the use of the 222 Rn and 3 He methods. While these studies give broadly concordant results, many questions remain unanswered. The wind velocity dependence of gas exchange rate has yet to be established in field studies. The dependence of gas exchange rate on molecular diffusivity also remains in limbo. Finally, the degree of enhancement of CO 2 exchange through chemical reactions has been only partially explored. 49 references, 2 figures, 2 tables

DNA template strand sequencing of single-cells maps genomic rearrangements at high resolution

OpenAIRE

Falconer, Ester; Hills, Mark; Naumann, Ulrike; Poon, Steven S. S.; Chavez, Elizabeth A.; Sanders, Ashley D.; Zhao, Yongjun; Hirst, Martin; Lansdorp, Peter M.

2012-01-01

DNA rearrangements such as sister chromatid exchanges (SCEs) are sensitive indicators of genomic stress and instability, but they are typically masked by single-cell sequencing techniques. We developed Strand-seq to independently sequence parental DNA template strands from single cells, making it possible to map SCEs at orders-of-magnitude greater resolution than was previously possible. On average, murine embryonic stem (mES) cells exhibit eight SCEs, which are detected at a resolution of up...

Newmark-Beta-FDTD method for super-resolution analysis of time reversal waves

Science.gov (United States)

Shi, Sheng-Bing; Shao, Wei; Ma, Jing; Jin, Congjun; Wang, Xiao-Hua

2017-09-01

In this work, a new unconditionally stable finite-difference time-domain (FDTD) method with the split-field perfectly matched layer (PML) is proposed for the analysis of time reversal (TR) waves. The proposed method is very suitable for multiscale problems involving microstructures. The spatial and temporal derivatives in this method are discretized by the central difference technique and Newmark-Beta algorithm, respectively, and the derivation results in the calculation of a banded-sparse matrix equation. Since the coefficient matrix keeps unchanged during the whole simulation process, the lower-upper (LU) decomposition of the matrix needs to be performed only once at the beginning of the calculation. Moreover, the reverse Cuthill-Mckee (RCM) technique, an effective preprocessing technique in bandwidth compression of sparse matrices, is used to improve computational efficiency. The super-resolution focusing of TR wave propagation in two- and three-dimensional spaces is included to validate the accuracy and efficiency of the proposed method.

A Baseline Method for Genealogical Entity Resolution

NARCIS (Netherlands)

Efremova, J.; Ranjbar-Sahraei, B.; Oliehoek, F.A.; Calders, T.; Tuyls, K.

2014-01-01

In this paper we study the application of entity resolution (ER) techniques on a real-world multi-source genealogical dataset. Our goal is to identify all persons involved in various notary acts and link them to their birth, marriage and death certificates. In order to evaluate the performance of a

Abstracts of International Conference on Experimental and Computing Methods in High Resolution Diffraction Applied for Structure Characterization of Modern Materials - HREDAMM

International Nuclear Information System (INIS)

2004-01-01

The conference addressed all aspects of high resolution diffraction. The topics of meeting include advanced experimental diffraction methods and computer data analysis for characterization of modern materials as well as the progress and new achievements in high resolution diffraction (X-ray, electrons, neutrons). Application of these methods for characterization of modern materials are widely presented among the invited, oral and poster contributions

Hydrogen/deuterium exchange, a unique and effective method for MS fragmentation behavior elucidation of ginkgolides and its application to systematic research in Ginkgo biloba.

Science.gov (United States)

Niu, Xingliang; Luo, Jun; Xu, Deran; Zou, Hongyan; Kong, Lingyi

2017-02-05

Ginkgolides, the main active constituents of Ginkgo biloba, possess significant selectively inhibition on platelet-activating factor and pancreatic lipase and attract wide attention in pharmacological research area. In our study, an effective hydrogen/deuterium (H/D) exchange method was developed by exchanging the α-Hs of lactone groups in ginkgolides with Ds, which was very useful for the elucidation of the fragmentation patterns of ginkgolides in Quadrupole Time-of-flight Mass Spectrometry (Q-TOF-MS), especially in accurately distinguishing the type and position of substituent in framework of ginkgolides. Then, a systematic research strategy for qualitative and quantitative analysis of ginkgolides, based on H/D exchange, tandem solid-phase extraction and LC-Q-TOF-MS, was developed, which was successfully applied in each medicinal part of G. biloba, which indicated that ginkgolide B was the most abundant ginkgolide in the seeds of G. biloba (60.6μg/g). This research was the successful application of H/D exchange in natural products, and proved that H/D exchange is a potential method for analysis research of complex TCMs active constituents. Copyright © 2016 Elsevier B.V. All rights reserved.

High resolution neutron spectroscopy - a tool for the investigation of dynamics of polymers and soft matter; La spectroscopie de neutrons a haute resolution-un outil pour l'etude de la dynamique des polymeres et de la matiere molle

Energy Technology Data Exchange (ETDEWEB)

Monkenbusch, M.; Richter, D. [Institut fur Festkorperforschung (IFF), Forschungszentrum Julich, Julich (Germany)

2007-09-15

Neutron scattering, with the ability to vary the contrast of molecular items by hydrogen/deuterium exchanges, is an invaluable tool for soft matter research. Besides the structural information on the mesoscopic scale that is obtained by diffraction methods like small angle neutron scattering, the slow dynamics of molecular motion on mesoscopic scale is accessible by high resolution neutron spectroscopy. The basic features of neutron backscattering spectroscopy, and in particular neutron spin-echo spectroscopy, are presented, in combination with illustrations of results from polymer melt dynamics to protein dynamics which are obtained by these techniques. (authors)

Graphene-coated polymeric anion exchangers for ion chromatography

Energy Technology Data Exchange (ETDEWEB)

Zhang, Kai; Cao, Minyi; Lou, Chaoyan [Department of Chemistry, Xixi Campus, Zhejiang University, Hangzhou 310028 (China); Wu, Shuchao, E-mail: wushch2002@163.com [Zhejiang Institute of Geology and Mineral Resources, Hangzhou 310007 (China); Zhang, Peimin [Department of Chemistry, Xixi Campus, Zhejiang University, Hangzhou 310028 (China); Zhi, Mingyu [Hangzhou Vocational & Technical College, Hangzhou, 310018 (China); Zhu, Yan, E-mail: zhuyan@zju.edu.cn [Department of Chemistry, Xixi Campus, Zhejiang University, Hangzhou 310028 (China)

2017-06-01

Carbonaceous stationary phases have gained much attention for their peculiar selectivity and robustness. Herein we report the fabrication and application of a graphene-coated polymeric stationary phase for anion exchange chromatography. The graphene-coated particles were fabricated by a facile evaporation-reduction method. These hydrophilic particles were proven appropriate substrates for grafting of hyperbranched condensation polymers (HBCPs) to make pellicular anion exchangers. The new phase was characterized by zeta potentials, Fourier transform infrared spectroscopy, thermogravimetry and scanning electron microscope. Frontal displacement chromatography showed that the capacities of the anion exchangers were tuned by both graphene amount and HBCPs layer count. The chromatographic performance of graphene-coated anion exchangers was demonstrated with separation of inorganic anions, organic acids, carbohydrates and amino acids. Good reproducibility was obtained by consecutive injections, indicating high chemical stability of the coating. - Highlights: • Graphene-coated polymeric particles were fabricated by a facile method. • Hyperbranched condensation polymers (HBCPs) were grafted from graphene-coated particles to make anion exchangers. • Graphene amount and HBCPs layer count had significant effects on the anion exchange capacities. • Separation of diverse anionic analytes on the anion exchangers was demonstrated. • The prepared anion exchangers exhibited high stability.

Resolution analysis by random probing

NARCIS (Netherlands)

Fichtner, Andreas; van Leeuwen, T.

2015-01-01

We develop and apply methods for resolution analysis in tomography, based on stochastic probing of the Hessian or resolution operators. Key properties of our methods are (i) low algorithmic complexity and easy implementation, (ii) applicability to any tomographic technique, including full‐waveform

Stability conditions for exact-exchange Kohn-Sham methods and their relation to correlation energies from the adiabatic-connection fluctuation-dissipation theorem.

Science.gov (United States)

Bleiziffer, Patrick; Schmidtel, Daniel; Görling, Andreas

2014-11-28

The occurrence of instabilities, in particular singlet-triplet and singlet-singlet instabilities, in the exact-exchange (EXX) Kohn-Sham method is investigated. Hessian matrices of the EXX electronic energy with respect to the expansion coefficients of the EXX effective Kohn-Sham potential in an auxiliary basis set are derived. The eigenvalues of these Hessian matrices determine whether or not instabilities are present. Similar as in the corresponding Hartree-Fock case instabilities in the EXX method are related to symmetry breaking of the Hamiltonian operator for the EXX orbitals. In the EXX methods symmetry breaking can easily be visualized by displaying the local multiplicative exchange potential. Examples (N2, O2, and the polyyne C10H2) for instabilities and symmetry breaking are discussed. The relation of the stability conditions for EXX methods to approaches calculating the Kohn-Sham correlation energy via the adiabatic-connection fluctuation-dissipation (ACFD) theorem is discussed. The existence or nonexistence of singlet-singlet instabilities in an EXX calculation is shown to indicate whether or not the frequency-integration in the evaluation of the correlation energy is singular in the EXX-ACFD method. This method calculates the Kohn-Sham correlation energy through the ACFD theorem theorem employing besides the Coulomb kernel also the full frequency-dependent exchange kernel and yields highly accurate electronic energies. For the case of singular frequency-integrands in the EXX-ACFD method a regularization is suggested. Finally, we present examples of molecular systems for which the self-consistent field procedure of the EXX as well as the Hartree-Fock method can converge to more than one local minimum depending on the initial conditions.

Stability conditions for exact-exchange Kohn-Sham methods and their relation to correlation energies from the adiabatic-connection fluctuation-dissipation theorem

International Nuclear Information System (INIS)

Bleiziffer, Patrick; Schmidtel, Daniel; Görling, Andreas

2014-01-01

The occurrence of instabilities, in particular singlet-triplet and singlet-singlet instabilities, in the exact-exchange (EXX) Kohn-Sham method is investigated. Hessian matrices of the EXX electronic energy with respect to the expansion coefficients of the EXX effective Kohn-Sham potential in an auxiliary basis set are derived. The eigenvalues of these Hessian matrices determine whether or not instabilities are present. Similar as in the corresponding Hartree-Fock case instabilities in the EXX method are related to symmetry breaking of the Hamiltonian operator for the EXX orbitals. In the EXX methods symmetry breaking can easily be visualized by displaying the local multiplicative exchange potential. Examples (N 2 , O 2 , and the polyyne C 10 H 2 ) for instabilities and symmetry breaking are discussed. The relation of the stability conditions for EXX methods to approaches calculating the Kohn-Sham correlation energy via the adiabatic-connection fluctuation-dissipation (ACFD) theorem is discussed. The existence or nonexistence of singlet-singlet instabilities in an EXX calculation is shown to indicate whether or not the frequency-integration in the evaluation of the correlation energy is singular in the EXX-ACFD method. This method calculates the Kohn-Sham correlation energy through the ACFD theorem theorem employing besides the Coulomb kernel also the full frequency-dependent exchange kernel and yields highly accurate electronic energies. For the case of singular frequency-integrands in the EXX-ACFD method a regularization is suggested. Finally, we present examples of molecular systems for which the self-consistent field procedure of the EXX as well as the Hartree-Fock method can converge to more than one local minimum depending on the initial conditions

The determination of Plutonium content in urine using anion exchange resin method

International Nuclear Information System (INIS)

Mukh-Syaifudin

1996-01-01

The possibility of internal contamination by plutonium is usually determined through urine analysis. The technique involved the co-precipitation of plutonium with rhodizonic acid by the addition of sodium hydroxide, the re-extraction of Pu into concentrated HCl, dissolution of Pu in 8 N HCI + Cl 2 solution, and the purification of plutonium through AGI-X8 anion exchange resin in columns with a diameter of 4 and 7 mm. The eluent was evaporated and the residu was dissolved in 8 N HCI and then deposited directly onto a Lexan slide or electrodeposited onto a stainless steel disc and the alpha emission of Pu was counted by using alpha spectrometry. The results showed that the recoveries of Pu-242 tracer by using column 7 mm and direct deposition and electrodeposition methods were 28.783% and 16.444%, respectively. The recoveries of Pu-242 by using column 4 mm and direct deposition and electrodeposition methods were 64.834% and 55.661%, respectively. From the percentage of recovery, it can be concluded that the direct deposition method was relatively better than the electrodeposition method. The recovery of Pu-242 by using column of 4 mm in diameter was higher than that of column 7 mm

Object-based methods for individual tree identification and tree species classification from high-spatial resolution imagery

Science.gov (United States)

Wang, Le

2003-10-01

Modern forest management poses an increasing need for detailed knowledge of forest information at different spatial scales. At the forest level, the information for tree species assemblage is desired whereas at or below the stand level, individual tree related information is preferred. Remote Sensing provides an effective tool to extract the above information at multiple spatial scales in the continuous time domain. To date, the increasing volume and readily availability of high-spatial-resolution data have lead to a much wider application of remotely sensed products. Nevertheless, to make effective use of the improving spatial resolution, conventional pixel-based classification methods are far from satisfactory. Correspondingly, developing object-based methods becomes a central challenge for researchers in the field of Remote Sensing. This thesis focuses on the development of methods for accurate individual tree identification and tree species classification. We develop a method in which individual tree crown boundaries and treetop locations are derived under a unified framework. We apply a two-stage approach with edge detection followed by marker-controlled watershed segmentation. Treetops are modeled from radiometry and geometry aspects. Specifically, treetops are assumed to be represented by local radiation maxima and to be located near the center of the tree-crown. As a result, a marker image was created from the derived treetop to guide a watershed segmentation to further differentiate overlapping trees and to produce a segmented image comprised of individual tree crowns. The image segmentation method developed achieves a promising result for a 256 x 256 CASI image. Then further effort is made to extend our methods to the multiscales which are constructed from a wavelet decomposition. A scale consistency and geometric consistency are designed to examine the gradients along the scale-space for the purpose of separating true crown boundary from unwanted

Spectral Resolution for Five-Element, Filtered, X-Ray Detector (XRD) Arrays Using the Methods of Backus and Gilbert

International Nuclear Information System (INIS)

FEHL, DAVID LEE; BIGGS, F.; CHANDLER, GORDON A.; STYGAR, WILLIAM A.

2000-01-01

The generalized method of Backus and Gilbert (BG) is described and applied to the inverse problem of obtaining spectra from a 5-channel, filtered array of x-ray detectors (XRD's). This diagnostic is routinely fielded on the Z facility at Sandia National Laboratories to study soft x-ray photons ((le)2300 eV), emitted by high density Z-pinch plasmas. The BG method defines spectral resolution limits on the system of response functions that are in good agreement with the unfold method currently in use. The resolution so defined is independent of the source spectrum. For noise-free, simulated data the BG approximating function is also in reasonable agreement with the source spectrum (150 eV black-body) and the unfold. This function may be used as an initial trial function for iterative methods or a regularization model

PRO-QUEST: a rapid assessment method based on progressive saturation for quantifying exchange rates using saturation times in CEST.

Science.gov (United States)

Demetriou, Eleni; Tachrount, Mohamed; Zaiss, Moritz; Shmueli, Karin; Golay, Xavier

2018-03-05

To develop a new MRI technique to rapidly measure exchange rates in CEST MRI. A novel pulse sequence for measuring chemical exchange rates through a progressive saturation recovery process, called PRO-QUEST (progressive saturation for quantifying exchange rates using saturation times), has been developed. Using this method, the water magnetization is sampled under non-steady-state conditions, and off-resonance saturation is interleaved with the acquisition of images obtained through a Look-Locker type of acquisition. A complete theoretical framework has been set up, and simple equations to obtain the exchange rates have been derived. A reduction of scan time from 58 to 16 minutes has been obtained using PRO-QUEST versus the standard QUEST. Maps of both T 1 of water and B 1 can simply be obtained by repetition of the sequence without off-resonance saturation pulses. Simulations and calculated exchange rates from experimental data using amino acids such as glutamate, glutamine, taurine, and alanine were compared and found to be in good agreement. The PRO-QUEST sequence was also applied on healthy and infarcted rats after 24 hours, and revealed that imaging specificity to ischemic acidification during stroke was substantially increased relative to standard amide proton transfer-weighted imaging. Because of the reduced scan time and insensitivity to nonchemical exchange factors such as direct water saturation, PRO-QUEST can serve as an excellent alternative for researchers and clinicians interested to map pH changes in vivo. © 2018 International Society for Magnetic Resonance in Medicine.

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.

A resolution-enhancing image reconstruction method for few-view differential phase-contrast tomography

Science.gov (United States)

Guan, Huifeng; Anastasio, Mark A.

2017-03-01

It is well-known that properly designed image reconstruction methods can facilitate reductions in imaging doses and data-acquisition times in tomographic imaging. The ability to do so is particularly important for emerging modalities such as differential X-ray phase-contrast tomography (D-XPCT), which are currently limited by these factors. An important application of D-XPCT is high-resolution imaging of biomedical samples. However, reconstructing high-resolution images from few-view tomographic measurements remains a challenging task. In this work, a two-step sub-space reconstruction strategy is proposed and investigated for use in few-view D-XPCT image reconstruction. It is demonstrated that the resulting iterative algorithm can mitigate the high-frequency information loss caused by data incompleteness and produce images that have better preserved high spatial frequency content than those produced by use of a conventional penalized least squares (PLS) estimator.

Two-photon exchange in elastic electron-nucleon scattering

International Nuclear Information System (INIS)

Blunden, P.G.; Melnitchouk, W.; Tjon, J.A.

2005-01-01

A detailed study of two-photon exchange in unpolarized and polarized elastic electron-nucleon scattering is presented, taking particular account of nucleon finite size effects. Contributions from nucleon elastic intermediate states are found to have a strong angular dependence, which leads to a partial resolution of the discrepancy between the Rosenbluth and polarization transfer measurements of the proton electric to magnetic form factor ratio, G E /G M . The two-photon exchange contribution to the longitudinal polarization transfer P L is small, whereas the contribution to the transverse polarization transfer P T is enhanced at backward angles by several percent, increasing with Q 2 . This gives rise to a small, E /G M obtained from the polarization transfer ratio P T /P L at large Q 2 . We also compare the two-photon exchange effects with data on the ratio of e + p to e - p cross sections, which is predicted to be enhanced at backward angles. Finally, we evaluate the corrections to the form factors of the neutron and estimate the elastic intermediate state contribution to the 3 He form factors

New developments in the discrete ordinate method for the resolution of the radiative transfer equation

International Nuclear Information System (INIS)

Ben Jaffel, L.; Vidal-Madjar, A.

1989-01-01

The discrete ordinate method for the resolution of the radiative transfer equation is developed. We show that the construction of a quasi-analytical solution to the corresponding matrix diagonalization problem reduces the time calculation and allows the use of more dense discrete frequency and angle grids. Comparison with previous work is made, showing that the present method reduces by more than a factor of ten the computational time, and is more appropriate in all cases

Comparison of methods for measuring the ion exchange capacity of a soil. Development of a quick method; Comparaison des methodes de mesure de la capacite d'echange d'ions d'un sol. Mise au point d'une methode rapide

Energy Technology Data Exchange (ETDEWEB)

Amavis, R [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

1959-07-01

In the course of a study on the movement of radioactive ions in soil we had to measure the cationic exchange capacity of various soil samples, this parameter being one of the most important in the appreciation of the extent of fixation of radioactive ions in the ground. The object of this report is to describe the various methods used and to compare the results obtained. A colorimetric method, using Co(NH{sub 3}){sub 6}{sup 3+} as exchangeable ion, was developed. It gives results comparable to those obtained with conventional methods, whilst considerably reducing the time necessary for the operations. (author) [French] A l'occasion de l'etude du mouvement des ions radio-actifs dans un sol, nous avons ete amenes a mesurer la capacite d'echange cationique de differents echantillons de sols; ce parametre etant un des plus importants pour apprecier la valeur de la fixation des ions radioactifs dans un terrain. L'objet de ce rapport est d'exposer les diverses methodes utilisees et de comparer les resultats obtenus. Une methode calorimetrique, utilisant Co(NH{sub 3}){sub 6}{sup 3+} comme ion echangeable, a ete mise au point: elle donne des resultats comparables a ceux obtenus avec les methodes habituelles et permet de reduire considerablement la duree des manipulations. (auteur)

Eculizumab Therapy Leads to Rapid Resolution of Thrombocytopenia in Atypical Hemolytic Uremic Syndrome

Directory of Open Access Journals (Sweden)

Han-Mou Tsai

2014-01-01

Full Text Available Eculizumab is highly effective in controlling complement activation in patients with the atypical hemolytic uremic syndrome (aHUS. However, the course of responses to the treatment is not well understood. We reviewed the responses to eculizumab therapy for aHUS. The results show that, in patients with aHUS, eculizumab therapy, when not accompanied with concurrent plasma exchange therapy, led to steady increase in the platelet count and improvement in extra-renal complications within 3 days. By day 7, the platelet count was normal in 15 of 17 cases. The resolution of hemolytic anemia and improvement in renal function were less predictable and were not apparent for weeks to months in two patients. The swift response in the platelet counts was only observed in one of five cases who received concurrent plasma exchange therapy and was not observed in a case of TMA due to gemcitabine/carboplatin. In summary, eculizumab leads to rapid increase in the platelet counts and resolution of extrarenal symptoms in patients with aHUS. Concurrent plasma exchange greatly impedes the response of aHUS to eculizumab therapy. Eculizumab is ineffective for gemcitabine/carboplatin associated TMA.

High resolution time integration for SN radiation transport

International Nuclear Information System (INIS)

Thoreson, Greg; McClarren, Ryan G.; Chang, Jae H.

2009-01-01

First-order, second-order, and high resolution time discretization schemes are implemented and studied for the discrete ordinates (S N ) equations. The high resolution method employs a rate of convergence better than first-order, but also suppresses artificial oscillations introduced by second-order schemes in hyperbolic partial differential equations. The high resolution method achieves these properties by nonlinearly adapting the time stencil to use a first-order method in regions where oscillations could be created. We employ a quasi-linear solution scheme to solve the nonlinear equations that arise from the high resolution method. All three methods were compared for accuracy and convergence rates. For non-absorbing problems, both second-order and high resolution converged to the same solution as the first-order with better convergence rates. High resolution is more accurate than first-order and matches or exceeds the second-order method

A method to characterize structure and symmetry in low-resolution images of colloidal thin films

International Nuclear Information System (INIS)

McDonald, Matthew J; Yethiraj, Anand; Beaulieu, L Y

2012-01-01

A method is presented for characterizing particle centres, particle size and crystal symmetries with sub-pixel resolution from 8-bit digital images of colloidal thin films taken with a scanning electron microscope (SEM). Digital images are converted to xyz data points by converting colour contrast to a numerical intensity. The data are then passed through a modified form of a Savitzky–Golay filter which allows particle centres to be determined. A subsequent routine is presented that, by analysing the weighted standard deviation and average intensity of the pixels along shifting rings, improves the accuracy of the detected particle centres and provides the radius of each particle. Obtaining the particle centres allows the symmetry of each particle (with respect to its neighbours) along with the mean crystal orientation to be obtained, all in one cohesive package. A key advantage of the method presented here is that it is very robust and works with both low- and high-resolution images—enabling, for example, routine quantitative analysis of SEM images. Because of the low level of user input, the method can be used to process a batch of images in order to characterize the evolution of samples. (paper)

Gas exchange rates measured using a dual-tracer (SF6 and3he) method in the coastal waters of Korea

Science.gov (United States)

Lee, Hyun-Woo; Lee, Kitack; Kaown, Duk-In

2008-03-01

Over a period of 5 days between August 12 and 17, 2005, we performed a gas exchange experiment using the dual tracer method in a tidal coastal ocean located off the southern coast of Korea. The gas exchange rate was determined from temporal changes in the ratio of3He to SF6 measured daily in the surface mixed layer. The measured gas exchange rate ( k CO 2), normalized to a Schmidt number of 600 for CO2 in fresh water at 20°C, was approximately 5.0 cm h-1 at a mean wind speed of 3.9 m s-1 during the study period. This value is significantly less than those obtained from floating chamber-based experiments performed previously in estuarine environments, but is similar in magnitude to values obtained using the dual tracer method in river and tidal coastal waters and values predicted on the basis of the relationship between the gas exchange rate and wind speed (Wanninkhof 1992), which is generally applicable to the open ocean. Our result is also consistent with the relationship of Raymond and Cole (2001), which was derived from experiments carried out in estuarine environments using222Rn and chlorofluorocarbons along with measurements undertaken in the Hudson River, Canada, using SF6 and3He. Our results indicate that tidal action in a microtidal region did not discernibly enhance the measured k CO 2 value.

A high-resolution neutron spectra unfolding method using the Genetic Algorithm technique

CERN Document Server

Mukherjee, B

2002-01-01

The Bonner sphere spectrometers (BSS) are commonly used to determine the neutron spectra within various nuclear facilities. Sophisticated mathematical tools are used to unfold the neutron energy distribution from the output data of the BSS. This paper highlights a novel high-resolution neutron spectra-unfolding method using the Genetic Algorithm (GA) technique. The GA imitates the biological evolution process prevailing in the nature to solve complex optimisation problems. The GA method was utilised to evaluate the neutron energy distribution, average energy, fluence and equivalent dose rates at important work places of a DIDO class research reactor and a high-energy superconducting heavy ion cyclotron. The spectrometer was calibrated with a sup 2 sup 4 sup 1 Am/Be (alpha,n) neutron standard source. The results of the GA method agreed satisfactorily with the results obtained by using the well-known BUNKI neutron spectra unfolding code.

Did you have an impact? A theory-based method for planning and evaluating knowledge-transfer and exchange activities in occupational health and safety.

Science.gov (United States)

Kramer, Desré M; Wells, Richard P; Carlan, Nicolette; Aversa, Theresa; Bigelow, Philip P; Dixon, Shane M; McMillan, Keith

2013-01-01

Few evaluation tools are available to assess knowledge-transfer and exchange interventions. The objective of this paper is to develop and demonstrate a theory-based knowledge-transfer and exchange method of evaluation (KEME) that synthesizes 3 theoretical frameworks: the promoting action on research implementation of health services (PARiHS) model, the transtheoretical model of change, and a model of knowledge use. It proposes a new term, keme, to mean a unit of evidence-based transferable knowledge. The usefulness of the evaluation method is demonstrated with 4 occupational health and safety knowledge transfer and exchange (KTE) implementation case studies that are based upon the analysis of over 50 pre-existing interviews. The usefulness of the evaluation model has enabled us to better understand stakeholder feedback, frame our interpretation, and perform a more comprehensive evaluation of the knowledge use outcomes of our KTE efforts.

Monte Carlo Planning Method Estimates Planning Horizons during Interactive Social Exchange.

Science.gov (United States)

Hula, Andreas; Montague, P Read; Dayan, Peter

2015-06-01

Reciprocating interactions represent a central feature of all human exchanges. They have been the target of various recent experiments, with healthy participants and psychiatric populations engaging as dyads in multi-round exchanges such as a repeated trust task. Behaviour in such exchanges involves complexities related to each agent's preference for equity with their partner, beliefs about the partner's appetite for equity, beliefs about the partner's model of their partner, and so on. Agents may also plan different numbers of steps into the future. Providing a computationally precise account of the behaviour is an essential step towards understanding what underlies choices. A natural framework for this is that of an interactive partially observable Markov decision process (IPOMDP). However, the various complexities make IPOMDPs inordinately computationally challenging. Here, we show how to approximate the solution for the multi-round trust task using a variant of the Monte-Carlo tree search algorithm. We demonstrate that the algorithm is efficient and effective, and therefore can be used to invert observations of behavioural choices. We use generated behaviour to elucidate the richness and sophistication of interactive inference.

Optimal design of tests for heat exchanger fouling identification

International Nuclear Information System (INIS)

Palmer, Kyle A.; Hale, William T.; Such, Kyle D.; Shea, Brian R.; Bollas, George M.

2016-01-01

Highlights: • Built-in test design that optimizes the information extractable from the said test. • Method minimizes the covariance of a fault with system uncertainty. • Method applied for the identification and quantification of heat exchanger fouling. • Heat exchanger fouling is identifiable despite the uncertainty in inputs and states. - Graphical Abstract: - Abstract: Particulate fouling in plate fin heat exchangers of aircraft environmental control systems is a recurring issue in environments rich in foreign object debris. Heat exchanger fouling detection, in terms of quantification of its severity, is critical for aircraft maintenance scheduling and safe operation. In this work, we focus on methods for offline fouling detection during aircraft ground handling, where the allowable variability range of admissible inputs is wider. We explore methods of optimal experimental design to estimate heat exchanger inputs and input trajectories that maximize the identifiability of fouling. In particular, we present a methodology in which D-optimality is used as a criterion for statistically significant inference of heat exchanger fouling in uncertain environments. The optimal tests are designed on the basis of a heat exchanger model of the inherent mass, energy and momentum balances, validated against literature data. The model is then used to infer sensitivities of the heat exchanger outputs with respect to fouling metrics and maximize them by manipulating input trajectories; thus enhancing the accuracy in quantifying the fouling extent. The proposed methodology is evaluated with statistical indices of the confidence in estimating thermal fouling resistance at uncertain operating conditions, explored in a series of case studies.

Conflict resolution patterns and violence perpetration in adolescent couples: A gender-sensitive mixed-methods approach.

Science.gov (United States)

Fernet, Mylène; Hébert, Martine; Paradis, Alison

2016-06-01

This study used a sequential two-phase explanatory design. The first phase of this mixed-methods design aimed to explore conflict resolution strategies in adolescent dating couples, and the second phase to document, from both the perspective of the individual and of the couple, dyadic interaction patterns distinguishing youth inflicting dating violence from those who do not. A sample of 39 heterosexual couples (mean age 17.8 years) participated in semi-structured interviews and were observed during a 45 min dyadic interaction. At phase 1, qualitative analysis revealed three main types of conflict resolution strategies: 1) negotiating expectations and individual needs; 2) avoiding conflicts or their resolution; 3) imposing personal needs and rules through the use of violence. At phase 2, we focused on couples with conflictive patterns. Results indicate that couples who inflict violence differ from nonviolent couples by their tendency to experience conflicts when in disagreement and to resort to negative affects as a resolution strategy. In addition, while at an individual level, they show a tendency to withdraw from conflict and to use less positive affect, at a dyadic level they present less symmetry. Results offer important insights for prevention programs. Copyright © 2016. Published by Elsevier Ltd.

A METHOD TO CALIBRATE THE HIGH-RESOLUTION CATANIA ASTROPHYSICAL OBSERVATORY SPECTROPOLARIMETER

Energy Technology Data Exchange (ETDEWEB)

Leone, F.; Gangi, M.; Giarrusso, M.; Scalia, C. [Università di Catania, Dipartimento di Fisica e Astronomia, Sezione Astrofisica, Via S. Sofia 78, I-95123 Catania (Italy); Avila, G. [ESO, Karl-Schwarzschild-Straße 2, D-85748, Garching bei München (Germany); Bellassai, G.; Bruno, P.; Catalano, S.; Benedetto, R. Di; Stefano, A. Di; Greco, V.; Martinetti, E.; Miraglia, M.; Munari, M.; Pontoni, C.; Scuderi, S.; Spanó, P. [INAF—Osservatorio Astrofisico di Catania, Via S. Sofia 78, I-95123 Catania (Italy)

2016-05-01

The Catania Astrophysical Observatory Spectropolarimeter (CAOS) is a white-pupil cross-dispersed échelle spectrograph with a spectral resolution of up to R  = 55,000 in the 375–1100 nm range in a single exposure, with complete coverage up to 856 nm. CAOS is linked to the 36-inch telescope, at Mount Etna Observatory, with a couple of 100 μ m optical fibers and it achieves a signal-to-noise ratio better than 60 for a V  = 10 mag star in one hour. CAOS is thermally stabilized in temperature within a 0.01 K rms, so that radial velocities are measured with a precision better than 100 m s{sup −1} from a single spectral line. Linear and circular spectropolarimetric observations are possible by means of a Savart plate working in series with a half-wave and a quarter-wave retarder plate in the 376–850 nm range. As is usual for high-resolution spectropolarimeters, CAOS is suitable to measure all Stokes parameters across spectral lines and it cannot measure the absolute degree of polarization. Observations of unpolarized standard stars show that instrumental polarization is generally zero at 550 nm and can increase up to 3% at the other wavelengths. Since polarized and unpolarized standard stars are useless, we suggest a method to calibrate a high-resolution spectropolarimeter on the basis of the polarimetric properties of spectral lines formed in the presence of a magnetic field. As applied to CAOS, observations of magnetic chemically peculiar stars of the main sequence show that the cross-talk from linear to circular polarization is smaller than 0.4% and that conversion from circular to linear is less than 2.7%. Strength and wavelength dependences of cross-talk can be entirely ascribed, via numerical simulations, to the incorrect retardance of achromatic wave plates.

Experimental (e, 2e) study of exchange interferences in the resonant Auger decay of Ar induced by electron impact

International Nuclear Information System (INIS)

Paripás, Béla; Palásthy, Béla; Žitnik, Matjaz

2013-01-01

Highlights: •The interference of autoionizing resonances with a common final ionic state is measured. •We have developed a method to experimentally verify for the exchange interference effect. •The sum of kinetic energies of the two detected electrons is kept constant. •Mainly the interference effects of [2p 3/2 ]4p and [2p 1/2 ]4p resonances in argon are studied. •The results possibly indicate small exchange interference effects. -- Abstract: Any two autoionizing resonances with a common final ionic state can be made to interfere by an appropriate selection of electron impact energy. To reveal the exchange interference effects a selective detection of electron pairs related to the selected final state is desired. We have performed a constant ionic state (e, 2e) experiment (CIS) isolating the final state by keeping the sum of transmission energies of two independent electron spectrometers constant. In the focus of this work are the exchange interference effects of 2p 3/2 −1 4p and 2p 1/2 −1 4p resonances in argon decaying to the 3p −2 ( 1 D)4p 2 P, 2 D final ionic state with energy E F = 37.3 ± 0.2 eV. We have developed a method to experimentally verify for the exchange interference effect. It is based on a comparison of the CIS spectrum recorded at the critical primary electron energy that activates the interferences, and the constructed, interference-free CIS spectrum that is build up from the CIS spectrum measured at primary electron energy away from the critical value. The results possibly indicate small exchange interference effects that may have been considerably smeared out at present experimental energy resolution

Application of Micro-coprecipitation Method to Alpha Source Preparation for Measuring Alpha Nuclides

International Nuclear Information System (INIS)

Lee, Myung Ho; Park, Jong Ho; Oh, Se Jin; Song, Byung Chul; Song, Kyuseok

2011-01-01

Among the source preparations, an electrodeposition is a commonly used method for the preparation of sources for an alpha spectrometry, because this technique is simple and produces a very thin deposit, which is essential for a high resolution of the alpha peak. Recently, micro-coprecipitation with rare earths have been used to yield sources for -spectrometry. In this work, the Pu, Am and Cm isotopes were purified from hindrance nuclides and elements with an a TRU resin in radioactive waste samples, and the activity concentrations of the Pu, Am and Cm isotopes were determined by radiation counting methods after alpha source preparation like micro coprecipitation. After the Pu isotopes in the radioactive waste samples were separated from the other nuclides with an anion exchange resin, the Am isotopes were purified with a TRU resin and an anion exchange resin or a TRU resin. Activity concentrations and chemical recoveries of 241 Am purified with the TRU resin were similar to those with the TRU resin and anion exchange resin. In this study, to save on the analytical time and cost, the Am isotopes were purified with the TRU resin without using an additional anion exchange resin. After comparing the electrodeposition method with the micro-coprecipitation method, the micro-coprecipitation method was used for the alpha source preparation, because the micro-coprecipitation method is simple and more reliable for source preparation of the Pu, Am and Cm isotopes

A Novel Method to Implement the Matrix Pencil Super Resolution Algorithm for Indoor Positioning

Directory of Open Access Journals (Sweden)

Tariq Jamil Saifullah Khanzada

2011-10-01

Full Text Available This article highlights the estimation of the results for the algorithms implemented in order to estimate the delays and distances for the indoor positioning system. The data sets for the transmitted and received signals are captured at a typical outdoor and indoor area. The estimation super resolution algorithms are applied. Different state of art and super resolution techniques based algorithms are applied to avail the optimal estimates of the delays and distances between the transmitted and received signals and a novel method for matrix pencil algorithm is devised. The algorithms perform variably at different scenarios of transmitted and received positions. Two scenarios are experienced, for the single antenna scenario the super resolution techniques like ESPRIT (Estimation of Signal Parameters via Rotational Invariance Technique and theMatrix Pencil algorithms give optimal performance compared to the conventional techniques. In two antenna scenario RootMUSIC and Matrix Pencil algorithm performed better than other algorithms for the distance estimation, however, the accuracy of all the algorithms is worst than the single antenna scenario. In all cases our devised Matrix Pencil algorithm achieved the best estimation results.

A novel method for selective separation of {sup 111}In from impurities by ion exchange chromatography

Energy Technology Data Exchange (ETDEWEB)

Yavari, R.; Khanachi, A.R.; Ghannad Maragheh, M.; Bagheri, G. [Jaber Ibn-e Hayan Research Laboratories, A.E.O.I., Tehran (Iran)

2004-07-01

{sup 111}In is one of the most important cyclotron-produced radionuclides that is prepared from nuclear reactions like Cd (p,xn){sup 111}In and Cd (d,xn) {sup 111}In. It is used in various branches of medicine such as lymphoscintigraphy and cisternography. Several methods have been reported in the literature for the separation of carrier-free {sup 111}In from irradiated cadmium matrix. But there has not been a sufficiently fast method for this purpose until recently. In this work, a new method has been developed for the separation of {sup 111}In from a cadmium target by using Dowex 50W-X8 as an ion exchanger. (orig.)

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

Conformational exchange of aromatic side chains characterized by L-optimized TROSY-selected ¹³C CPMG relaxation dispersion.

Science.gov (United States)

Weininger, Ulrich; Respondek, Michal; Akke, Mikael

2012-09-01

Protein dynamics on the millisecond time scale commonly reflect conformational transitions between distinct functional states. NMR relaxation dispersion experiments have provided important insights into biologically relevant dynamics with site-specific resolution, primarily targeting the protein backbone and methyl-bearing side chains. Aromatic side chains represent attractive probes of protein dynamics because they are over-represented in protein binding interfaces, play critical roles in enzyme catalysis, and form an important part of the core. Here we introduce a method to characterize millisecond conformational exchange of aromatic side chains in selectively (13)C labeled proteins by means of longitudinal- and transverse-relaxation optimized CPMG relaxation dispersion. By monitoring (13)C relaxation in a spin-state selective manner, significant sensitivity enhancement can be achieved in terms of both signal intensity and the relative exchange contribution to transverse relaxation. Further signal enhancement results from optimizing the longitudinal relaxation recovery of the covalently attached (1)H spins. We validated the L-TROSY-CPMG experiment by measuring fast folding-unfolding kinetics of the small protein CspB under native conditions. The determined unfolding rate matches perfectly with previous results from stopped-flow kinetics. The CPMG-derived chemical shift differences between the folded and unfolded states are in excellent agreement with those obtained by urea-dependent chemical shift analysis. The present method enables characterization of conformational exchange involving aromatic side chains and should serve as a valuable complement to methods developed for other types of protein side chains.

Optimized anion exchange column isolation of zirconium-89 (89Zr) from yttrium cyclotron target: Method development and implementation on an automated fluidic platform.

Science.gov (United States)

O'Hara, Matthew J; Murray, Nathaniel J; Carter, Jennifer C; Morrison, Samuel S