Trace elements detection in whole food samples by Neutron Activation Analysis, k0-method

International Nuclear Information System (INIS)

Sathler, Márcia Maia; Menezes, Maria Ângela de Barros Correia; Salles, Paula Maria Borges de

2017-01-01

Inorganic elements, from natural and anthropogenic sources are present in foods in different concentrations. With the increase in anthropogenic activities, there was also a considerable increase in the emission of these elements in the environment, leading to the need of monitoring the elemental composition of foods available for consumption. Numerous techniques have been used to detect inorganic elements in biological and environmental matrices, always aiming at reaching lower detection limits in order to evaluate the trace element content in the sample. Neutron activation analysis (INAA), applying the k 0 -method, produces accurate and precise results without the need of chemical preparation of the samples – that could cause their contamination. This study evaluated the presence of inorganic elements in whole foods samples, mainly elements on trace levels. For this purpose, seven samples of different types of whole foods were irradiated in the TRIGA MARK I IPR-R1 research reactor - located at CDTN/CNEN, in Belo Horizonte, MG. It was possible to detect twenty two elements above the limit of detection in, at least, one of the samples analyzed. This study reaffirms the INAA, k 0 - method, as a safe and efficient technique for detecting trace elements in food samples. (author)

[Efficiency of photodecomposition of trace NDMA in water by UV irradiation].

Science.gov (United States)

Xu, Bing-Bing; Chen, Zhong-Lin; Qi, Fei; Ma, Jun

2008-07-01

Efficiency of photodecomposition of trace NDMA by UV irradiation was investigated with analyzing the initial concentration of NDMA, solution pH, irradiation area, irradiation intensity and water quality effect on NDMA photolysis. NDMA could be effectively photodegraded by UV irradiation. The removal efficiency of NDMA was 97.5% after 5 min of UV irradiation. Effect of initial NDMA concentration on photodecomposition of NDMA was not remarkable. With pH value ascending, the removal rate of NDMA photodecomposition decreased. The yields of photoquantum were more under lower solution pH than that under higher pH. NDMA had fastest reaction rate at solution pH = 2.2. Removal efficiency of NDMA increased with the available irradiation area ascending. Increscent ultraviolet irradiation intensity was good for NDMA degradation. Water quality affected the removal of NDMA slightly. The removal efficiency of NDMA in tap water and Songhua River raw water were 96.7% and 94.8%, respectively.

METHOD OF CONJUGATED CIRCULAR ARCS TRACING

Directory of Open Access Journals (Sweden)

N. Ageyev Vladimir

2017-01-01

Full Text Available The geometric properties of conjugated circular arcs connecting two points on the plane with set directions of tan- gent vectors are studied in the work. It is shown that pairs of conjugated circular arcs with the same conditions in frontier points create one-parameter set of smooth curves tightly filling all the plane. One of the basic properties of this set is the fact that all coupling points of circular arcs are on the circular curve going through the initially given points. The circle radius depends on the direction of tangent vectors. Any point of the circle curve, named auxiliary in this work, determines a pair of conjugated arcs with given boundary conditions. One more condition of the auxiliary circle curve is that it divides the plane into two parts. The arcs going from the initial point are out of the circle limited by this circle curve and the arcs coming to the final point are inside it. These properties are the basis for the method of conjugated circular arcs tracing pro- posed in this article. The algorithm is rather simple and allows to fulfill all the needed plottings using only the divider and ruler. Two concrete examples are considered. The first one is related to the problem of tracing of a pair of conjugated arcs with the minimal curve jump when going through the coupling point. The second one demonstrates the possibility of trac- ing of the smooth curve going through any three points on the plane under condition that in the initial and final points the directions of tangent vectors are given. The proposed methods of conjugated circular arcs tracing can be applied in solving of a wide variety of problems connected with the tracing of cam contours, for example pattern curves in textile industry or in computer-aided-design systems when programming of looms with numeric control.

Efficiency of Choice Set Generation Methods for Bicycle Routes

DEFF Research Database (Denmark)

Halldórsdóttir, Katrín; Rieser-Schüssler, Nadine; W. Axhausen, Kay

behaviour, observed choices and alternatives composing the choice set of each cyclist are necessary. However, generating the alternative choice sets can prove challenging. This paper analyses the efficiency of various choice set generation methods for bicycle routes in order to contribute to our...... travelling information with GPS loggers, compared to self-reported RP data, is more accurate geographic locations and routes. Also, the GPS traces give more reliable information on times and prevent trip underreporting, and it is possible to collect information on many trips by the same person without...

Reverse ray tracing for transformation optics.

Science.gov (United States)

Hu, Chia-Yu; Lin, Chun-Hung

2015-06-29

Ray tracing is an important technique for predicting optical system performance. In the field of transformation optics, the Hamiltonian equations of motion for ray tracing are well known. The numerical solutions to the Hamiltonian equations of motion are affected by the complexities of the inhomogeneous and anisotropic indices of the optical device. Based on our knowledge, no previous work has been conducted on ray tracing for transformation optics with extreme inhomogeneity and anisotropicity. In this study, we present the use of 3D reverse ray tracing in transformation optics. The reverse ray tracing is derived from Fermat's principle based on a sweeping method instead of finding the full solution to ordinary differential equations. The sweeping method is employed to obtain the eikonal function. The wave vectors are then obtained from the gradient of that eikonal function map in the transformed space to acquire the illuminance. Because only the rays in the points of interest have to be traced, the reverse ray tracing provides an efficient approach to investigate the illuminance of a system. This approach is useful in any form of transformation optics where the material property tensor is a symmetric positive definite matrix. The performance and analysis of three transformation optics with inhomogeneous and anisotropic indices are explored. The ray trajectories and illuminances in these demonstration cases are successfully solved by the proposed reverse ray tracing method.

Method development for trace and ultratrace analysis

International Nuclear Information System (INIS)

Anon.

1992-01-01

Method development, that is, selection of a mode of chromatography and the right column and mobile-phase combination for trace and ultratrace analysis, requires several main considerations. The method should be useful for resolving various trace and ultratrace components present in the sample. If the nature of these components is known, the choice of method may be straightforward, that is, a selection can be made from the following modes of HPLC: (1) adsorption chromatography; (2) normal-phase chromatography; (3) reversed-phase chromatography; (4) ion-pair chromatography; (5) ion-exchange chromatography; (6) ion chromatography. Unfortunately, the nature of all of the components is frequently unknown. However, several intelligent judgments can be made on the nature of impurities. This chapter deals with some basic approaches to mobile-phase selection and optimization. More detailed information may be found in basic texts. Techniques for separation of high-molecular-weight compounds (macromolecules) and chiral compounds may be found elsewhere. Mainly compounds with molecular weight lower than 2,000 are discussed here. 123 refs

A new method for automated discontinuity trace mapping on rock mass 3D surface model

Science.gov (United States)

Li, Xiaojun; Chen, Jianqin; Zhu, Hehua

2016-04-01

This paper presents an automated discontinuity trace mapping method on a 3D surface model of rock mass. Feature points of discontinuity traces are first detected using the Normal Tensor Voting Theory, which is robust to noisy point cloud data. Discontinuity traces are then extracted from feature points in four steps: (1) trace feature point grouping, (2) trace segment growth, (3) trace segment connection, and (4) redundant trace segment removal. A sensitivity analysis is conducted to identify optimal values for the parameters used in the proposed method. The optimal triangular mesh element size is between 5 cm and 6 cm; the angle threshold in the trace segment growth step is between 70° and 90°; the angle threshold in the trace segment connection step is between 50° and 70°, and the distance threshold should be at least 15 times the mean triangular mesh element size. The method is applied to the excavation face trace mapping of a drill-and-blast tunnel. The results show that the proposed discontinuity trace mapping method is fast and effective and could be used as a supplement to traditional direct measurement of discontinuity traces.

Trace elements detection in whole food samples by Neutron Activation Analysis, k{sub 0}-method

Energy Technology Data Exchange (ETDEWEB)

Sathler, Márcia Maia; Menezes, Maria Ângela de Barros Correia, E-mail: maia.sathler@gmail.com, E-mail: menezes@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Salles, Paula Maria Borges de, E-mail: pauladesalles@yahoo.com.br [Universidade Federal de Minas Gerais (DEN/UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear

2017-07-01

Inorganic elements, from natural and anthropogenic sources are present in foods in different concentrations. With the increase in anthropogenic activities, there was also a considerable increase in the emission of these elements in the environment, leading to the need of monitoring the elemental composition of foods available for consumption. Numerous techniques have been used to detect inorganic elements in biological and environmental matrices, always aiming at reaching lower detection limits in order to evaluate the trace element content in the sample. Neutron activation analysis (INAA), applying the k{sub 0}-method, produces accurate and precise results without the need of chemical preparation of the samples – that could cause their contamination. This study evaluated the presence of inorganic elements in whole foods samples, mainly elements on trace levels. For this purpose, seven samples of different types of whole foods were irradiated in the TRIGA MARK I IPR-R1 research reactor - located at CDTN/CNEN, in Belo Horizonte, MG. It was possible to detect twenty two elements above the limit of detection in, at least, one of the samples analyzed. This study reaffirms the INAA, k{sub 0} - method, as a safe and efficient technique for detecting trace elements in food samples. (author)

The importance of radiochemistry and indicator methods for the chemistry of traces

International Nuclear Information System (INIS)

Benes, P.; Majer, V.

1980-01-01

Sensitivity is compared for common chemical methods with respect to nonradioactive materials and methods for determining trace amounts of radioactive substances. The concept of trace amounts is explained and some other notions and terms are discussed from the point of view of chemistry and radiochemistry. The problem of radiation effect is briefly assessed on a sample of material containing trace amounts of a radionuclide and the isotopic effect problem in hydrogen is treated. (M.S.)

Highly efficient removal of trace thallium from contaminated source waters with ferrate: Role of in situ formed ferric nanoparticle.

Science.gov (United States)

Liu, Yulei; Wang, Lu; Wang, Xianshi; Huang, Zhuangsong; Xu, Chengbiao; Yang, Tao; Zhao, Xiaodan; Qi, Jingyao; Ma, Jun

2017-11-01

Thallium (Tl) is highly toxic to mammals and relevant pollution cases are increasing world-widely. Convenient and efficient method for the removal of trace Tl from contaminated source water is imperative. Here, the removal of trace Tl by K 2 FeO 4 [Fe(VI)] was investigated for the first time, with the exploration of reaction mechanisms. Six different types of water treatment agents (powdered activated carbon, Al 2 (SO 4 ) 3 , FeCl 3 , δ-MnO 2 , MnO 2 nano-particles, and K 2 FeO 4 ) were used for the removal of Tl in spiked river water, and K 2 FeO 4 showed excellent removal performance. Over 92% of Tl (1 μg/L) was removed within 5 min by applying 2.5 mg/L of K 2 FeO 4 (pH 7.0, 20 °C). XPS analysis revealed that in the reaction of Tl(I) with K 2 FeO 4 , Tl(I) was oxidized to Tl(III), and removed by the K 2 FeO 4 reduced ferric particles. The removal of Tl by in situ formed and ex situ formed ferric particle was examined respectively, and the results revealed that the removal of trace Tl could be attributed to the combination of adsorption and coprecipitation processes. The hydrodynamic size of the reduced particle from K 2 FeO 4 ranged from 10 nm to 100 nm, and its surface was negatively charged under neutral pH condition. These factors were conducive for the efficient removal of Tl by K 2 FeO 4 . The effects of solution pH, coexisting ions (Na + , Ca 2+ , and HCO 3 - ), humic acid, solution temperature, and reductive environment on the removal and desorption of Tl were investigated, and the elimination of Tl in polluted river water and reservoir water was performed. These results suggest that K 2 FeO 4 could be an efficient and convenient agent on trace Tl removal. Copyright © 2017. Published by Elsevier Ltd.

Application of the efficiency tracing method to the liquid scintillation metrology of 3H and 14C dual-labelled samples; Aplicacion del metodo de la figura de merito a la metrologia por centelleo liquido de muestras doblemente marcadas con 3H y 14C.

Energy Technology Data Exchange (ETDEWEB)

Martin-Casallo, M. T.; Los Arcos, J. M.; Grau, A.

1989-07-01

Two calculation procedures have been tested for the application of the efficiency tracing method to the activity determination of 3H and 14C dual- -labelled samples in the liquid scintillation metrology. A procedure Ieads to the statement of a linear equations system as a function of the quenching parameter, while the other one uses a least-square algorithm to fit the total count rate against the quenching parameter. The first procedure is strongly sensitive to the statistical uncertainty on the partial efficiencies and produces discrepancies which may reach more than 100% compared to the real values. The second procedure leads to more reliable results, showing discrepancies between 0.1% and 0.6% for the 3H activity and between 0.6% and 5% for the 14C activity, as that the efficiency tracing method can be applied to the metro- logy of dual-labelled samples of 3H and 14C by means of this procedure. (Author) 7 refs.

The Combinatorial Trace Method in Action

Science.gov (United States)

Krebs, Mike; Martinez, Natalie C.

2013-01-01

On any finite graph, the number of closed walks of length k is equal to the sum of the kth powers of the eigenvalues of any adjacency matrix. This simple observation is the basis for the combinatorial trace method, wherein we attempt to count (or bound) the number of closed walks of a given length so as to obtain information about the graph's…

Simple Methods to Approximate CPC Shape to Preserve Collection Efficiency

Directory of Open Access Journals (Sweden)

David Jafrancesco

2012-01-01

Full Text Available The compound parabolic concentrator (CPC is the most efficient reflective geometry to collect light to an exit port. Anyway, to allow its actual use in solar plants or photovoltaic concentration systems, a tradeoff between system efficiency and cost reduction, the two key issues for sunlight exploitation, must be found. In this work, we analyze various methods to model an approximated CPC aimed to be simpler and more cost-effective than the ideal one, as well as to preserve the system efficiency. The manufacturing easiness arises from the use of truncated conic surfaces only, which can be realized by cheap machining techniques. We compare different configurations on the basis of their collection efficiency, evaluated by means of nonsequential ray-tracing software. Moreover, due to the fact that some configurations are beam dependent and for a closer approximation of a real case, the input beam is simulated as nonsymmetric, with a nonconstant irradiance on the CPC internal surface.

Quantitative numerical method for analysing slip traces observed by AFM

International Nuclear Information System (INIS)

Veselý, J; Cieslar, M; Coupeau, C; Bonneville, J

2013-01-01

Atomic force microscopy (AFM) is used more and more routinely to study, at the nanometre scale, the slip traces produced on the surface of deformed crystalline materials. Taking full advantage of the quantitative height data of the slip traces, which can be extracted from these observations, requires however an adequate and robust processing of the images. In this paper an original method is presented, which allows the fitting of AFM scan-lines with a specific parameterized step function without any averaging treatment of the original data. This yields a quantitative and full description of the changes in step shape along the slip trace. The strength of the proposed method is established on several typical examples met in plasticity by analysing nano-scale structures formed on the sample surface by emerging dislocations. (paper)

Epidemic contact tracing via communication traces.

Directory of Open Access Journals (Sweden)

Katayoun Farrahi

Full Text Available Traditional contact tracing relies on knowledge of the interpersonal network of physical interactions, where contagious outbreaks propagate. However, due to privacy constraints and noisy data assimilation, this network is generally difficult to reconstruct accurately. Communication traces obtained by mobile phones are known to be good proxies for the physical interaction network, and they may provide a valuable tool for contact tracing. Motivated by this assumption, we propose a model for contact tracing, where an infection is spreading in the physical interpersonal network, which can never be fully recovered; and contact tracing is occurring in a communication network which acts as a proxy for the first. We apply this dual model to a dataset covering 72 students over a 9 month period, for which both the physical interactions as well as the mobile communication traces are known. Our results suggest that a wide range of contact tracing strategies may significantly reduce the final size of the epidemic, by mainly affecting its peak of incidence. However, we find that for low overlap between the face-to-face and communication interaction network, contact tracing is only efficient at the beginning of the outbreak, due to rapidly increasing costs as the epidemic evolves. Overall, contact tracing via mobile phone communication traces may be a viable option to arrest contagious outbreaks.

Epidemic contact tracing via communication traces.

Science.gov (United States)

Farrahi, Katayoun; Emonet, Rémi; Cebrian, Manuel

2014-01-01

Traditional contact tracing relies on knowledge of the interpersonal network of physical interactions, where contagious outbreaks propagate. However, due to privacy constraints and noisy data assimilation, this network is generally difficult to reconstruct accurately. Communication traces obtained by mobile phones are known to be good proxies for the physical interaction network, and they may provide a valuable tool for contact tracing. Motivated by this assumption, we propose a model for contact tracing, where an infection is spreading in the physical interpersonal network, which can never be fully recovered; and contact tracing is occurring in a communication network which acts as a proxy for the first. We apply this dual model to a dataset covering 72 students over a 9 month period, for which both the physical interactions as well as the mobile communication traces are known. Our results suggest that a wide range of contact tracing strategies may significantly reduce the final size of the epidemic, by mainly affecting its peak of incidence. However, we find that for low overlap between the face-to-face and communication interaction network, contact tracing is only efficient at the beginning of the outbreak, due to rapidly increasing costs as the epidemic evolves. Overall, contact tracing via mobile phone communication traces may be a viable option to arrest contagious outbreaks.

Efficient sample preparation method based on solvent-assisted dispersive solid-phase extraction for the trace detection of butachlor in urine and waste water samples.

Science.gov (United States)

Aladaghlo, Zolfaghar; Fakhari, Alireza; Behbahani, Mohammad

2016-10-01

In this work, an efficient sample preparation method termed solvent-assisted dispersive solid-phase extraction was applied. The used sample preparation method was based on the dispersion of the sorbent (benzophenone) into the aqueous sample to maximize the interaction surface. In this approach, the dispersion of the sorbent at a very low milligram level was achieved by inserting a solution of the sorbent and disperser solvent into the aqueous sample. The cloudy solution created from the dispersion of the sorbent in the bulk aqueous sample. After pre-concentration of the butachlor, the cloudy solution was centrifuged and butachlor in the sediment phase dissolved in ethanol and determined by gas chromatography with flame ionization detection. Under the optimized conditions (solution pH = 7.0, sorbent: benzophenone, 2%, disperser solvent: ethanol, 500 μL, centrifuged at 4000 rpm for 3 min), the method detection limit for butachlor was 2, 3 and 3 μg/L for distilled water, waste water, and urine sample, respectively. Furthermore, the preconcentration factor was 198.8, 175.0, and 174.2 in distilled water, waste water, and urine sample, respectively. Solvent-assisted dispersive solid-phase extraction was successfully used for the trace monitoring of butachlor in urine and waste water samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Efficiency and Privacy Enhancement for a Track and Trace System of RFID-Based Supply Chains

Directory of Open Access Journals (Sweden)

Xunjun Chen

2015-06-01

Full Text Available One of the major applications of Radio Frequency Identification (RFID technology is in supply chain management as it promises to provide real-time visibility based on the function of track and trace. However, such an RFID-based track and trace system raises new security and privacy challenges due to the restricted resource of tags. In this paper, we refine three privacy related models (i.e., the privacy, path unlinkability, and tag unlinkability of RFID-based track and trace systems, and clarify the relations among these privacy models. Specifically, we have proven that privacy is equivalent to path unlinkability and tag unlinkability implies privacy. Our results simplify the privacy concept and protocol design for RFID-based track and trace systems. Furthermore, we propose an efficient track and trace scheme, Tracker+, which allows for authentic and private identification of RFID-tagged objects in supply chains. In the Tracker+, no computational ability is required for tags, but only a few bytes of storage (such as EPC Class 1 Gen 2 tags are needed to store the tag state. Indeed, Tracker+ reduces the memory requirements for each tag by one group element compared to the Tracker presented in other literature. Moreover, Tracker+ provides privacy against supply chain inside attacks.

Cultivation and optimized tracing of rat bone marrow mesenchymal stem cells

Directory of Open Access Journals (Sweden)

Xiu-hua HE

2011-02-01

Full Text Available Objective To investigate labelling and tracing methods of bone marrow mesenchymal stem cells(MSCs of rat,and to optimize the trace labelling technique.Methods Rat MSCs were isolated and cultured in vitro.The surface antigens(CD29,CD34,CD45,CD90 of MSCs were identified by flow cytometry,and MSCs were labelled with BrdU,DAPI and GFP,respectively.The labelling efficiency of BrdU was aseessed with immunocytochemistry,and that of DAPI and GFP were observed under fluorescence microscope.The advantages and disadvantages of the three tracer techniques were analyzed.Results Flow cytometry showed that MSCs expressed CD29 and CD90 but not CD34 or CD45.The three kinds of markers showed no significant toxicity to the cells.The optimal dosage and timing of BrdU labeling were respectively 10 μmol/L and 48 hours.And that of DAPI labeling were 1μg/ml and 12 hours.The infected MSCs with lentivirus-GFP at MOI(multiplicity of infection = 8 for 12h expressed GFP with high efficiency(above 90%.Conclusion Comparison with the three tracing methods for MSCs,transfection with GFP gene is a stable,reliable,safe tracing method,and they are important in tracing adult stem cells.

Comparison of Methods to Trace Multiple Subskills: Is LR-DBN Best?

Science.gov (United States)

Xu, Yanbo; Mostow, Jack

2012-01-01

A long-standing challenge for knowledge tracing is how to update estimates of multiple subskills that underlie a single observable step. We characterize approaches to this problem by how they model knowledge tracing, fit its parameters, predict performance, and update subskill estimates. Previous methods allocated blame or credit among subskills…

A new method for automatic discontinuity traces sampling on rock mass 3D model

Science.gov (United States)

Umili, G.; Ferrero, A.; Einstein, H. H.

2013-02-01

A new automatic method for discontinuity traces mapping and sampling on a rock mass digital model is described in this work. The implemented procedure allows one to automatically identify discontinuity traces on a Digital Surface Model: traces are detected directly as surface breaklines, by means of maximum and minimum principal curvature values of the vertices that constitute the model surface. Color influence and user errors, that usually characterize the trace mapping on images, are eliminated. Also trace sampling procedures based on circular windows and circular scanlines have been implemented: they are used to infer trace data and to calculate values of mean trace length, expected discontinuity diameter and intensity of rock discontinuities. The method is tested on a case study: results obtained applying the automatic procedure on the DSM of a rock face are compared to those obtained performing a manual sampling on the orthophotograph of the same rock face.

Methods Research about Accuracy Loss Tracing of Dynamic Measurement System Based on WNN

International Nuclear Information System (INIS)

Lin, S-W; Fei, Y T; Jiang, M L; Tsai, C-Y; Cheng Hsinyu

2006-01-01

The paper presents a method of achieving accuracy loss of the dynamic measurement system according to change of errors on different period of the system. WNN, used to trace the accuracy loss of dynamic measurement system, traces the total precision loss during a certain period to every part of the system, and the accuracy loss of every part can be get, so retaining the accuracy and optimum design of the system is possible. Take tracing the accuracy loss of a simulated system for an example to testify the method

Analysis of Trace Pharmaceuticals and Related Compounds in Municipal Wastewaters by Preconcentration, Chromatography, Derivatization, and Separation Methods

Directory of Open Access Journals (Sweden)

Petra Camilla Lindholm

2014-05-01

Full Text Available A significant portion of pharmaceuticals and other organic chemicals consumed by people and animals are released into municipal wastewater treatment plants. Most of them are degraded during the wastewater treatment processes, but some of them degrade only partially and may be widely transported and dispersed into the aquatic environment. This is why efficient and fast analytical methods are needed for detection of organic compounds in wastewaters at trace levels. Because wastewaters often consist of complex matrices and high-molecular mass materials, e.g., lignocellulosic biomass, which may bring challenges to the sample preparation procedures, efficient pre-concentration methods such as solid phase extraction (SPE solid phase microextraction (SPME, or single drop microextraction (SDME are needed. The most common analysis methods are gas chromatography (GC and liquid chromatography (LC coupled with tandem mass spectrometry (MS/MS. The aim of this review is to give an overview of chromatographic and spectroscopic methods when characterizing low- and medium-molecular weight organic pollutants, mainly focusing on pharmaceuticals, biocides, and personal care products in environmental matrices.

Introducing GAMER: A Fast and Accurate Method for Ray-tracing Galaxies Using Procedural Noise

Science.gov (United States)

Groeneboom, N. E.; Dahle, H.

2014-03-01

We developed a novel approach for fast and accurate ray-tracing of galaxies using procedural noise fields. Our method allows for efficient and realistic rendering of synthetic galaxy morphologies, where individual components such as the bulge, disk, stars, and dust can be synthesized in different wavelengths. These components follow empirically motivated overall intensity profiles but contain an additional procedural noise component that gives rise to complex natural patterns that mimic interstellar dust and star-forming regions. These patterns produce more realistic-looking galaxy images than using analytical expressions alone. The method is fully parallelized and creates accurate high- and low- resolution images that can be used, for example, in codes simulating strong and weak gravitational lensing. In addition to having a user-friendly graphical user interface, the C++ software package GAMER is easy to implement into an existing code.

Introducing GAMER: A fast and accurate method for ray-tracing galaxies using procedural noise

International Nuclear Information System (INIS)

Groeneboom, N. E.; Dahle, H.

2014-01-01

We developed a novel approach for fast and accurate ray-tracing of galaxies using procedural noise fields. Our method allows for efficient and realistic rendering of synthetic galaxy morphologies, where individual components such as the bulge, disk, stars, and dust can be synthesized in different wavelengths. These components follow empirically motivated overall intensity profiles but contain an additional procedural noise component that gives rise to complex natural patterns that mimic interstellar dust and star-forming regions. These patterns produce more realistic-looking galaxy images than using analytical expressions alone. The method is fully parallelized and creates accurate high- and low- resolution images that can be used, for example, in codes simulating strong and weak gravitational lensing. In addition to having a user-friendly graphical user interface, the C++ software package GAMER is easy to implement into an existing code.

Introducing GAMER: A fast and accurate method for ray-tracing galaxies using procedural noise

Energy Technology Data Exchange (ETDEWEB)

Groeneboom, N. E.; Dahle, H., E-mail: nicolaag@astro.uio.no [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, N-0315 Oslo (Norway)

2014-03-10

We developed a novel approach for fast and accurate ray-tracing of galaxies using procedural noise fields. Our method allows for efficient and realistic rendering of synthetic galaxy morphologies, where individual components such as the bulge, disk, stars, and dust can be synthesized in different wavelengths. These components follow empirically motivated overall intensity profiles but contain an additional procedural noise component that gives rise to complex natural patterns that mimic interstellar dust and star-forming regions. These patterns produce more realistic-looking galaxy images than using analytical expressions alone. The method is fully parallelized and creates accurate high- and low- resolution images that can be used, for example, in codes simulating strong and weak gravitational lensing. In addition to having a user-friendly graphical user interface, the C++ software package GAMER is easy to implement into an existing code.

Trace elements in human milk. Part of a coordinated programme on comparative methods for the study of trace elements in human nutrition

International Nuclear Information System (INIS)

Kosta, L.

1981-01-01

New analytical methods based on radiochemical neutron activation analysis were developed for the determination of Sn, V, I and Se at nanogram levels in biological materials, particularly in milk and other foodstuffs. By the application of these and similar methods, results for trace elements in human and cow's milk were collected from which the normal concentration ranges of up to 12 trace elements were established. Significant data on vanadium levels were also collected allowing assessment of the dietary intake and body pool of this element and a reappraisal of its significance in nutrition. Similar data on a smaller scale were also collected for tin. Results were also obtained for several different trace elements in a range of biological reference materials

The complementary use of radioanalytical methods and trace analysis methods for the characterisation of environmental IAEA reference materials

International Nuclear Information System (INIS)

De Regge, P.; Burns, K.; Campbell, M.; Makarewicz, M.; Markowicz, A.; Mattiuzzi, M.; Tajani, A.; Toervenyi, A.; Zeiller, E.

2001-01-01

The IAEA laboratories have access to both nuclear analytical methods and conventional instrumental methods for trace analysis for the characterisation of its environmental and biological reference materials. A technical concept integrating the homogeneity data, the recommended test portion mass and the uncertainty on the trace element concentrations is explored using a combination of INAA, XRF, ICP-MS, ICP-AES, and AAS. The above approach is illustrated by selected examples of reference materials currently under evaluation for their trace element content. They include some or all of the following elements Al, As, Br, Ca, Cd, Co, Cr, Cs, Cu, Fe, Hg, K, Mg, Mn, Mo, Na, Ni, Pb, Rb, Se, Sr, Th, U, Zn in environmental biomonitor organisms (lichen, algae) and air dust filters. (author)

A new method to measure and increase the detection efficiency of a microchannel plate for 100 keV electrons

International Nuclear Information System (INIS)

Tornow, R.P.

1990-01-01

A new method is described which permits measurement of efficiency of a microchannel plate (MCP) simply by tracing the output current pulse in the saturated mode. The dependence of the detection efficiency on the gain of the input stages of a detector is calculated and the result is applied to a MCP. Furthermore, an enhancement of the detection efficiency of a MCP is presented for 100 keV electrons up to more than 90% by means of the field-enhanced secondary electron emission. (author)

Efficient Time-Domain Ray-Tracing Technique for the Analysis of Ultra-Wideband Indoor Environments including Lossy Materials and Multiple Effects

Directory of Open Access Journals (Sweden)

F. Saez de Adana

2009-01-01

Full Text Available This paper presents an efficient application of the Time-Domain Uniform Theory of Diffraction (TD-UTD for the analysis of Ultra-Wideband (UWB mobile communications for indoor environments. The classical TD-UTD formulation is modified to include the contribution of lossy materials and multiple-ray interactions with the environment. The electromagnetic analysis is combined with a ray-tracing acceleration technique to treat realistic and complex environments. The validity of this method is tested with measurements performed inside the Polytechnic building of the University of Alcala and shows good performance of the model for the analysis of UWB propagation.

Efficient Unsteady Flow Visualization with High-Order Access Dependencies

Energy Technology Data Exchange (ETDEWEB)

Zhang, Jiang; Guo, Hanqi; Yuan, Xiaoru

2016-04-19

We present a novel high-order access dependencies based model for efficient pathline computation in unsteady flow visualization. By taking longer access sequences into account to model more sophisticated data access patterns in particle tracing, our method greatly improves the accuracy and reliability in data access prediction. In our work, high-order access dependencies are calculated by tracing uniformly-seeded pathlines in both forward and backward directions in a preprocessing stage. The effectiveness of our proposed approach is demonstrated through a parallel particle tracing framework with high-order data prefetching. Results show that our method achieves higher data locality and hence improves the efficiency of pathline computation.

Efficient removal of trace antimony(III) through adsorption by hematite modified magnetic nanoparticles

International Nuclear Information System (INIS)

Shan, Chao; Ma, Zhiyao; Tong, Meiping

2014-01-01

Graphical abstract: - Highlights: • Sb(III) adsorption capacity of MNP@hematite was twice that of commercial Fe 3 O 4 . • pH, ionic strength, coexisting anions and NOM did not inhibit Sb(III) removal. • MNP@hematite could remove trace Sb(III) and As(III) from water simultaneously. • Efficient removal of Sb(III) from real tap water was achieved. • MNP@hematite could be easily recycled with a magnet and could be used repeatedly. - Abstract: Hematite coated magnetic nanoparticle (MNP@hematite) was fabricated through heterogeneous nucleation technique and used to remove trace Sb(III) from water. Powder X-ray diffraction, transmission electron microscopy (TEM), and alternating gradient magnetometry were utilized to characterize the prepared adsorbent. TEM image showed that MNP@hematite particles were spherical with size of 10–30 nm. With saturation magnetization of 27.0 emu/g, MNP@hematite particles could be easily separated from water with a simple magnetic process in short time (5 min). At initial concentration of 110 μg/L, Sb(III) was rapidly decreased to below 5 μg/L by MNP@hematite in 10 min. Sb(III) adsorption capacity of MNP@hematite was 36.7 mg/g, which was almost twice that of commercial Fe 3 O 4 nanoparticles. The removal of trace Sb(III) was not obviously affected by solution pH (over a wide range from 3 to 11), ionic strength (up to 100 mM), coexisting anions (chloride, nitrate, sulfate, carbonate, silicate, and phosphate, up to 10 mM) and natural organic matters (humic acid and alginate, up to 8 mg/L as TOC). Moreover, MNP@hematite particles were able to remove Sb(III) and As(III) simultaneously. Trace Sb(III) could also be effectively removed from real tap water by MNP@hematite. The magnetic adsorbent could be recycled and used repeatedly

Efficient removal of trace antimony(III) through adsorption by hematite modified magnetic nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Shan, Chao; Ma, Zhiyao; Tong, Meiping, E-mail: tongmeiping@pku.edu.cn

2014-03-01

Graphical abstract: - Highlights: • Sb(III) adsorption capacity of MNP@hematite was twice that of commercial Fe{sub 3}O{sub 4}. • pH, ionic strength, coexisting anions and NOM did not inhibit Sb(III) removal. • MNP@hematite could remove trace Sb(III) and As(III) from water simultaneously. • Efficient removal of Sb(III) from real tap water was achieved. • MNP@hematite could be easily recycled with a magnet and could be used repeatedly. - Abstract: Hematite coated magnetic nanoparticle (MNP@hematite) was fabricated through heterogeneous nucleation technique and used to remove trace Sb(III) from water. Powder X-ray diffraction, transmission electron microscopy (TEM), and alternating gradient magnetometry were utilized to characterize the prepared adsorbent. TEM image showed that MNP@hematite particles were spherical with size of 10–30 nm. With saturation magnetization of 27.0 emu/g, MNP@hematite particles could be easily separated from water with a simple magnetic process in short time (5 min). At initial concentration of 110 μg/L, Sb(III) was rapidly decreased to below 5 μg/L by MNP@hematite in 10 min. Sb(III) adsorption capacity of MNP@hematite was 36.7 mg/g, which was almost twice that of commercial Fe{sub 3}O{sub 4} nanoparticles. The removal of trace Sb(III) was not obviously affected by solution pH (over a wide range from 3 to 11), ionic strength (up to 100 mM), coexisting anions (chloride, nitrate, sulfate, carbonate, silicate, and phosphate, up to 10 mM) and natural organic matters (humic acid and alginate, up to 8 mg/L as TOC). Moreover, MNP@hematite particles were able to remove Sb(III) and As(III) simultaneously. Trace Sb(III) could also be effectively removed from real tap water by MNP@hematite. The magnetic adsorbent could be recycled and used repeatedly.

Energy efficient trace removal by extractive distillation

NARCIS (Netherlands)

Jongmans, M.T.G.

2012-01-01

Separation processes contribute for about 40–70 % to the total energy requirements of the chemical process industry. Especially when trace removal is required to manufacture high purity products, traditional separation technologies become extremely expensive and are not providing satisfying

Determination of trace elements in ground water by two preconcentration methods using atomic absorption spectrometry

International Nuclear Information System (INIS)

Elhag, A. Y.

2004-01-01

This is a comparative study between two different methods of preconcentration done to separate the trace elements cadmium, nickel. chromium, manganese, copper, zinc, and lead in drinking (ground) water samples taken from different locations in Gezira State, central Sudan (the map); these methods are (coprecipitation) with aluminium hydroxide and by Ammonium Pyrrolidine Dithiocarbamate (APDC) using Methyl Isobutyl Ketone (MIBK) as an organic solvent; and subsequent analysis by Atomic Absorption Spectrometry (AAS) for both methods. The result of comparison showed the superiority of the (APDC) coprecipitation method over the aluminium hydroxide coprecipitation method in the total percentage recoveries of the studied trace elements in drinking (ground) water samples, such results confirm previous studies. This study also involves direct analysis of these water samples by atomic absorption spectrometry to determine the concentrations of trace elements Cadmium, Nickel, Chromium, Manganese, Copper, Zinc and Lead and compare it to the corresponding guide line values described by the World Health Organization and the maximum concentrations of trace elements in drinking water permitted by the Sudanese Standards and Metrology Organizations (SSMO), where the concentrations of some elements in some samples were found to be different than the described values by both of the organizations. The study includes a trial to throw light on the effect of the proximity of the water samples sources to the Blue Nile river on its trace elements concentrations; no relation was proved to exist in that respect.(Author)

SOLFAST, a Ray-Tracing Monte-Carlo software for solar concentrating facilities

International Nuclear Information System (INIS)

Roccia, J P; Piaud, B; Coustet, C; Caliot, C; Guillot, E; Flamant, G; Delatorre, J

2012-01-01

In this communication, the software SOLFAST is presented. It is a simulation tool based on the Monte-Carlo method and accelerated Ray-Tracing techniques to evaluate efficiently the energy flux in concentrated solar installations.

An efficient and general numerical method to compute steady uniform vortices

Science.gov (United States)

Luzzatto-Fegiz, Paolo; Williamson, Charles H. K.

2011-07-01

Steady uniform vortices are widely used to represent high Reynolds number flows, yet their efficient computation still presents some challenges. Existing Newton iteration methods become inefficient as the vortices develop fine-scale features; in addition, these methods cannot, in general, find solutions with specified Casimir invariants. On the other hand, available relaxation approaches are computationally inexpensive, but can fail to converge to a solution. In this paper, we overcome these limitations by introducing a new discretization, based on an inverse-velocity map, which radically increases the efficiency of Newton iteration methods. In addition, we introduce a procedure to prescribe Casimirs and remove the degeneracies in the steady vorticity equation, thus ensuring convergence for general vortex configurations. We illustrate our methodology by considering several unbounded flows involving one or two vortices. Our method enables the computation, for the first time, of steady vortices that do not exhibit any geometric symmetry. In addition, we discover that, as the limiting vortex state for each flow is approached, each family of solutions traces a clockwise spiral in a bifurcation plot consisting of a velocity-impulse diagram. By the recently introduced "IVI diagram" stability approach [Phys. Rev. Lett. 104 (2010) 044504], each turn of this spiral is associated with a loss of stability for the steady flows. Such spiral structure is suggested to be a universal feature of steady, uniform-vorticity flows.

A hard tissue cephalometric comparative study between hand tracing and computerized tracing

Directory of Open Access Journals (Sweden)

Ramachandra Prabhakar

2014-01-01

Full Text Available Aims: To analyze and compare the angular and linear hard tissue cephalometric measurements using hand-tracing and computerized tracings with Nemoceph and Dolphin software systems. Subjects and Methods: A total of 30 cephalograms were randomly chosen for study with the following criteria, cephalograms of patients with good contrast, no distortion, and minimal radiographic artifacts were considered using the digital method (Kodak 8000 C with 12 angular and nine linear parameters selected for the study. Comparisons were determined by post-hoc test using Tukey HSD method. The N-Par tests were performed using Kruskal-Walli′s method. Statistical Analysis Used: ANOVA and post-hoc. Results: The results of this study show that there is no significant difference in the angular and linear measurements recorded. The P values were significant at 0.05 levels for two parameters, Co-A and Co-Gn with the hand-tracing method. This was significant in ANOVA and post-hoc test by Tukey HSD method. Conclusions: This study of comparison provides support for transition from digital hand to computerized tracing methodology. In fact, digital computerized tracings were easier and less time consuming, with the same reliability irrespective of each method of tracing.

Method for detecting trace impurities in gases

Science.gov (United States)

Freund, S.M.; Maier, W.B. II; Holland, R.F.; Beattie, W.H.

A technique for considerably improving the sensitivity and specificity of infrared spectrometry as applied to quantitative determination of trace impurities in various carrier or solvent gases is presented. A gas to be examined for impurities is liquefied and infrared absorption spectra of the liquid are obtained. Spectral simplification and number densities of impurities in the optical path are substantially higher than are obtainable in similar gas-phase analyses. Carbon dioxide impurity (approx. 2 ppM) present in commercial Xe and ppM levels of Freon 12 and vinyl chloride added to liquefied air are used to illustrate the method.

A Photoluminescence-Based Field Method for Detection of Traces of Explosives

Directory of Open Access Journals (Sweden)

E. Roland Menzel

2004-01-01

Full Text Available We report a photoluminescence-based field method for detecting traces of explosives. In its standard version, the method utilizes a commercially available color spot test kit for treating explosive traces on filter paper after swabbing. The colored products are fluorescent under illumination with a laser that operates on three C-size flashlight batteries and delivers light at 532 nm. In the fluorescence detection mode, by visual inspection, the typical sensitivity gain is a factor of 100. The method is applicable to a wide variety of explosives. In its time-resolved version, intended for in situ work, explosives are tagged with europium complexes. Instrumentation-wise, the time-resolved detection, again visual, can be accomplished in facile fashion. The europium luminescence excitation utilizes a laser operating at 355 nm. We demonstrate the feasibility of CdSe quantum dot sensitization of europium luminescence for time-resolved purposes. This would allow the use of the above 532 nm laser.

Trace Norm Regularized CANDECOMP/PARAFAC Decomposition With Missing Data.

Science.gov (United States)

Liu, Yuanyuan; Shang, Fanhua; Jiao, Licheng; Cheng, James; Cheng, Hong

2015-11-01

In recent years, low-rank tensor completion (LRTC) problems have received a significant amount of attention in computer vision, data mining, and signal processing. The existing trace norm minimization algorithms for iteratively solving LRTC problems involve multiple singular value decompositions of very large matrices at each iteration. Therefore, they suffer from high computational cost. In this paper, we propose a novel trace norm regularized CANDECOMP/PARAFAC decomposition (TNCP) method for simultaneous tensor decomposition and completion. We first formulate a factor matrix rank minimization model by deducing the relation between the rank of each factor matrix and the mode- n rank of a tensor. Then, we introduce a tractable relaxation of our rank function, and then achieve a convex combination problem of much smaller-scale matrix trace norm minimization. Finally, we develop an efficient algorithm based on alternating direction method of multipliers to solve our problem. The promising experimental results on synthetic and real-world data validate the effectiveness of our TNCP method. Moreover, TNCP is significantly faster than the state-of-the-art methods and scales to larger problems.

APPLICATION OF MODIFIED POWER FLOW TRACING METHOD FOR REACTIVE POWER PRICING IN PRACTICAL UTILITY SYSTEM

Directory of Open Access Journals (Sweden)

M. SUSITHRA

2017-01-01

Full Text Available Competitive trend towards restructuring and unbundling of transmission services has resulted in the need to discover the impact of a particular generator to load. This paper initially presents the analysis of three different reactive power valuation methods namely, Modified Ybus , Virtual flow approach and modified power flow tracing to compute the reactive power output from a particular generator to particular load. Among these methods, the modified power flow electricity tracing method is identified as the best method to trace the reactive power contribution from various reactive power sources to loads, transmission line, etc. Also this proposed method breakdown the total reactive power loss in a transmission line into components to be allocated to individual loads. Secondly, based on this Method a novel allocation method for reactive power service for practical system is proposed. Hence, this method can be useful in providing additional insight into power system operation and can be used to modify existing tariffs of charging for reactive power transmission loss and reactive power transmission services. Simulation and comparison results are shown by taking WSCC 9 and IEEE 30 bus system as test system.

Apparatus comprising trace element dosage and method for treating raw water in biofilter

DEFF Research Database (Denmark)

2015-01-01

the inlet (2) to the outlet (3) or in the reverse direction, - the trace element dosage device (13) is positioned upstream of the porous filter material and microbial biomass and is configured to dose trace element(s) to the water flowing through the filter. A method for treating raw water by microbial......Apparatus for treating raw water in a biofilter The present invention relates to an apparatus in which raw water is treated through microbial activity where microbial activity is controlled by nutrients and other parameters. Some of the nutrients controlling the microbial activity are trace...... elements such as certain metals (Cu, Co, Cr, Mo, Ni, W, Zn or a mixture thereof). The apparatus comprising - a volume provided with an inlet (2) for raw water and an outlet (3) for water having been subjected to microbial activity, a filter and a trace element dosage device (13) are placed in this volume...

Effects of source and receiver locations in predicting room transfer functions by a phased beam tracing method

DEFF Research Database (Denmark)

Jeong, Cheol-Ho; Ih, Jeong-Guon

2012-01-01

The accuracy of a phased beam tracing method in predicting transfer functions is investigated with a special focus on the positions of the source and receiver. Simulated transfer functions for various source-receiver pairs using the phased beam tracing method were compared with analytical Green’s...

Electrochemical preconcentration and hydride generation methods for trace determination of selenium by atomic absorption spectrometry

International Nuclear Information System (INIS)

Bye, R.

1986-01-01

The use of atomic absorption spectrometry in combination with two different preconcentration/separation techniques for the determination of trace concentrations of selenium is described. Electrochemical preconcentration onto a platinum electrode with a subsequent atomization of selenium is discussed briefly. Several parameters are considered such as the presence of depolarizers, and the temperature of the electrolyzed solutions. Special attention is payed to the efficiency of the atomization step, and a method to improve this is proposed. Applications of the technique to real samples are also reported. Secondly, the separation of the selenium as the volatile selenium hydride from the sample solution is considered. Several papers in this thesis deal with commonly occurring interferants as nickel and copper and with ways of minimizing or avoiding the interferring effects, whereas other papers relate to more theoretical aspects of the hydride generation process. New methods for the determination of selenium in technical samples with high contents of nickel and copper are also presented

Manual tracing versus smartphone application (app) tracing: a comparative study.

Science.gov (United States)

Sayar, Gülşilay; Kilinc, Delal Dara

2017-11-01

This study aimed to compare the results of conventional manual cephalometric tracing with those acquired with smartphone application cephalometric tracing. The cephalometric radiographs of 55 patients (25 females and 30 males) were traced via the manual and app methods and were subsequently examined with Steiner's analysis. Five skeletal measurements, five dental measurements and two soft tissue measurements were managed based on 21 landmarks. The durations of the performances of the two methods were also compared. SNA (Sella, Nasion, A point angle) and SNB (Sella, Nasion, B point angle) values for the manual method were statistically lower (p < .001) than those for the app method. The ANB value for the manual method was statistically lower than that of app method. L1-NB (°) and upper lip protrusion values for the manual method were statistically higher than those for the app method. Go-GN/SN, U1-NA (°) and U1-NA (mm) values for manual method were statistically lower than those for the app method. No differences between the two methods were found in the L1-NB (mm), occlusal plane to SN, interincisal angle or lower lip protrusion values. Although statistically significant differences were found between the two methods, the cephalometric tracing proceeded faster with the app method than with the manual method.

Ray Tracing for Real-time Games

NARCIS (Netherlands)

Bikker, J.

2012-01-01

This thesis describes efficient rendering algorithms based on ray tracing, and the application of these algorithms to real-time games. Compared to rasterizationbased approaches, rendering based on ray tracing allows elegant and correct simulation of important global effects, such as shadows,

Insights into Tikhonov regularization: application to trace gas column retrieval and the efficient calculation of total column averaging kernels

Directory of Open Access Journals (Sweden)

T. Borsdorff

2014-02-01

Full Text Available Insights are given into Tikhonov regularization and its application to the retrieval of vertical column densities of atmospheric trace gases from remote sensing measurements. The study builds upon the equivalence of the least-squares profile-scaling approach and Tikhonov regularization method of the first kind with an infinite regularization strength. Here, the vertical profile is expressed relative to a reference profile. On the basis of this, we propose a new algorithm as an extension of the least-squares profile scaling which permits the calculation of total column averaging kernels on arbitrary vertical grids using an analytic expression. Moreover, we discuss the effective null space of the retrieval, which comprises those parts of a vertical trace gas distribution which cannot be inferred from the measurements. Numerically the algorithm can be implemented in a robust and efficient manner. In particular for operational data processing with challenging demands on processing time, the proposed inversion method in combination with highly efficient forward models is an asset. For demonstration purposes, we apply the algorithm to CO column retrieval from simulated measurements in the 2.3 μm spectral region and to O3 column retrieval from the UV. These represent ideal measurements of a series of spaceborne spectrometers such as SCIAMACHY, TROPOMI, GOME, and GOME-2. For both spectral ranges, we consider clear-sky and cloudy scenes where clouds are modelled as an elevated Lambertian surface. Here, the smoothing error for the clear-sky and cloudy atmosphere is significant and reaches several percent, depending on the reference profile which is used for scaling. This underlines the importance of the column averaging kernel for a proper interpretation of retrieved column densities. Furthermore, we show that the smoothing due to regularization can be underestimated by calculating the column averaging kernel on a too coarse vertical grid. For both

Trace conditioning in insects-keep the trace!

Science.gov (United States)

Dylla, Kristina V; Galili, Dana S; Szyszka, Paul; Lüdke, Alja

2013-01-01

Trace conditioning is a form of associative learning that can be induced by presenting a conditioned stimulus (CS) and an unconditioned stimulus (US) following each other, but separated by a temporal gap. This gap distinguishes trace conditioning from classical delay conditioning, where the CS and US overlap. To bridge the temporal gap between both stimuli and to form an association between CS and US in trace conditioning, the brain must keep a neural representation of the CS after its termination-a stimulus trace. Behavioral and physiological studies on trace and delay conditioning revealed similarities between the two forms of learning, like similar memory decay and similar odor identity perception in invertebrates. On the other hand differences were reported also, like the requirement of distinct brain structures in vertebrates or disparities in molecular mechanisms in both vertebrates and invertebrates. For example, in commonly used vertebrate conditioning paradigms the hippocampus is necessary for trace but not for delay conditioning, and Drosophila delay conditioning requires the Rutabaga adenylyl cyclase (Rut-AC), which is dispensable in trace conditioning. It is still unknown how the brain encodes CS traces and how they are associated with a US in trace conditioning. Insects serve as powerful models to address the mechanisms underlying trace conditioning, due to their simple brain anatomy, behavioral accessibility and established methods of genetic interference. In this review we summarize the recent progress in insect trace conditioning on the behavioral and physiological level and emphasize similarities and differences compared to delay conditioning. Moreover, we examine proposed molecular and computational models and reassess different experimental approaches used for trace conditioning.

ACCELERATION RENDERING METHOD ON RAY TRACING WITH ANGLE COMPARISON AND DISTANCE COMPARISON

Directory of Open Access Journals (Sweden)

Liliana liliana

2007-01-01

Full Text Available In computer graphics applications, to produce realistic images, a method that is often used is ray tracing. Ray tracing does not only model local illumination but also global illumination. Local illumination count ambient, diffuse and specular effects only, but global illumination also count mirroring and transparency. Local illumination count effects from the lamp(s but global illumination count effects from other object(s too. Objects that are usually modeled are primitive objects and mesh objects. The advantage of mesh modeling is various, interesting and real-like shape. Mesh contains many primitive objects like triangle or square (rare. A problem in mesh object modeling is long rendering time. It is because every ray must be checked with a lot of triangle of the mesh. Added by ray from other objects checking, the number of ray that traced will increase. It causes the increasing of rendering time. To solve this problem, in this research, new methods are developed to make the rendering process of mesh object faster. The new methods are angle comparison and distance comparison. These methods are used to reduce the number of ray checking. The rays predicted will not intersect with the mesh, are not checked weather the ray intersects the mesh. With angle comparison, if using small angle to compare, the rendering process will be fast. This method has disadvantage, if the shape of each triangle is big, some triangles will be corrupted. If the angle to compare is bigger, mesh corruption can be avoided but the rendering time will be longer than without comparison. With distance comparison, the rendering time is less than without comparison, and no triangle will be corrupted.

Process-tracing methods in decision making: on growing up in the 70s

NARCIS (Netherlands)

Schulte-Mecklenbeck, M.; Johnson, J.G.; Böckenholt, U.; Goldstein, D.G.; Russo, J.E.; Sullivan, N.J.; Willemsen, M.C.

2017-01-01

Decision research has experienced a shift from simple algebraic theories of choice to an appreciation of mental processes underlying choice. A variety of process-tracing methods has helped researchers test these process explanations. Here, we provide a survey of these methods, including specific

Pseudo forward ray-tracing: A new method for surface validation in cornea topography

NARCIS (Netherlands)

Sicam, V.; Snellenburg, J.J.; van der Heijde, R.G.; van Stokkum, I.H.M.

2007-01-01

PURPOSE. A pseudo forward ray-tracing (PFRT) algorithm is developed to evaluate surface reconstruction in corneal topography. The method can be applied to topographers where one-to-one correspondence between mire and image points can be established. METHODS. The PFRT algorithm was applied on a

An Energy Conservative Ray-Tracing Method With a Time Interpolation of the Force Field

Energy Technology Data Exchange (ETDEWEB)

Yao, Jin [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2015-02-10

A new algorithm that constructs a continuous force field interpolated in time is proposed for resolving existing difficulties in numerical methods for ray-tracing. This new method has improved accuracy, but with the same degree of algebraic complexity compared to Kaisers method.

Performance of a novel multiple-signal luminescence sediment tracing method

Science.gov (United States)

Reimann, Tony

2014-05-01

Optically Stimulated Luminescence (OSL) is commonly used for dating sediments. Luminescence signals build up due to exposure of mineral grains to natural ionizing radiation, and are reset when these grains are exposed to (sun)light during sediment transport and deposition. Generally, luminescence signals can be read in two ways, potentially providing information on the burial history (dating) or the transport history (sediment tracing) of mineral grains. In this study we use a novel luminescence measurement procedure (Reimann et al., submitted) that simultaneously monitors six different luminescence signals from the same sub-sample (aliquot) to infer the transport history of sand grains. Daylight exposure experiments reveal that each of these six signals resets (bleaches) at a different rate, thus allowing to trace the bleaching history of the sediment in six different observation windows. To test the feasibility of luminescence sediment tracing in shallow-marine coastal settings we took eight sediment samples from the pilot mega-nourishment Zandmotor in Kijkduin (South-Holland). This site provides relatively controlled conditions as the morphological evolution of this nourishment is densely monitored (Stive et al., 2013). After sampling the original nourishment source we took samples along the seaward facing contour of the spit that was formed from August 2011 (start of nourishment) to June 2012 (sampling). It is presumed that these samples originate from the source and were transported and deposited within the first year after construction. The measured luminescence of a sediment sample was interpolated onto the daylight bleaching curve of each signal to assign the Equivalent Exposure Time (EET) to a sample. The EET is a quantitative measure of the full daylight equivalent a sample was exposed to during sediment transport, i.e. the higher the EET the longer the sample has been transported or the more efficient it has been exposed to day-light during sediment

Trace conditioning in insects – Keep the trace!

Directory of Open Access Journals (Sweden)

Kristina V Dylla

2013-08-01

Full Text Available Trace conditioning is a form of associative learning that can be induced by presenting a conditioned stimulus (CS and an unconditioned stimulus (US following each other, but separated by a temporal gap. This gap distinguishes trace conditioning from classical delay conditioning, where the CS and US overlap. To bridge the temporal gap between both stimuli and to form an association between CS and US in trace conditioning, the brain must keep a neural representation of the CS after its termination – a stimulus trace. Behavioral and physiological studies on trace and delay conditioning revealed similarities between the two forms of learning, like similar memory decay and similar odor identity perception in invertebrates. On the other hand differences were reported also, like the requirement of distinct brain structures in vertebrates or disparities in molecular mechanisms in both vertebrates and invertebrates. For example, in commonly used vertebrate conditioning paradigms the hippocampus is necessary for trace but not for delay conditioning, and Drosophila delay conditioning requires the Rutabaga adenylyl cyclase, which is dispensable in trace conditioning. It is still unknown how the brain encodes CS traces and how they are associated with a US in trace conditioning. Insects serve as powerful models to address the mechanisms underlying trace conditioning, due to their simple brain anatomy, behavioral accessibility and established methods of genetic interference. In this review we summarize the recent progress in insect trace conditioning on the behavioral and physiological level and emphasize similarities and differences compared to delay conditioning. Moreover, we examine proposed molecular and computational models and reassess different experimental approaches used for trace conditioning.

New method for mass spectrometric trace analysis of metals in biology and medicine

International Nuclear Information System (INIS)

Schulten, H.R.; Bahr, U.; Palavinskas, R.

1984-01-01

A first survey on the basic aspects and applications of a novel method for trace analyses of metals is given. The advantages of this methodology for analyses of trace metals which was developed by our group are: small sample amount, high sensitivity and selectivity, simple sample preparation for the measurement (no ashing) and reliability and precision of the results. The time consumption for one complete quantitative analysis lies below 30 min. The concentration of monoisotopic metals, as for example aluminium, cesium, manganese etc. is determined using a calibration curve. Using stable isotope dilution analysis quantification of metals with at least two stable isotopes further improved the precision of the results. If this technique is utilized, on one hand contamination of the environment by radioactive substances is avoided, on the other even the smallest changes in concentrations of trace metals are detected unambigeously. The accuracy of the resulting quantitative data has been confirmed test measurements with other analytical methods such as atomic absorption spectroscopy and thermal ionization mass spectrometry. Although there is no doubt that the greatest analytical capacity of field desorption mass spectrometry is in the field of high-molecular weight natural products, it has been possible in the last years to modify the method for qualitative and quantitative investigations of more than 60 metals. (orig./EF) [de

Trace spaces

DEFF Research Database (Denmark)

Fajstrup, Lisbeth; Goubault, Eric; Haucourt, Emmanuel

2012-01-01

in the interleaving semantics of a concurrent program, but rather some equivalence classes. The purpose of this paper is to describe a new algorithm to compute such equivalence classes, and a representative per class, which is based on ideas originating in algebraic topology. We introduce a geometric semantics...... of concurrent languages, where programs are interpreted as directed topological spaces, and study its properties in order to devise an algorithm for computing dihomotopy classes of execution paths. In particular, our algorithm is able to compute a control-flow graph for concurrent programs, possibly containing...... loops, which is “as reduced as possible” in the sense that it generates traces modulo equivalence. A preliminary implementation was achieved, showing promising results towards efficient methods to analyze concurrent programs, with very promising results compared to partial-order reduction techniques....

Kinetics as a tool to assess the immobilization of soil trace metals by binding phase amendments for in situ remediation purposes

International Nuclear Information System (INIS)

Varrault, Gilles; Bermond, Alain

2011-01-01

Highlights: → Assessment of the efficiency of soil remediation method by binding phase amendment. → Use of a kinetic fractionation method to assess trace metal mobility in amended soils. → Vernadite amendments are effective for lead and cadmium remediation. → IHA amendments are only effective for copper remediation. → Advantages of kinetic fractionation vs. extraction schemes performed at equilibrium. - Abstract: Many soil remediation techniques consist in decreasing the mobility of trace metals by means of adding trace metal binding phases. For this study, whose aim is to assess the efficiency of soil remediation method by binding phase amendment, a kinetic fractionation method that provides the labile and slowly labile trace metal amounts in soil has been introduced. Manganese oxides (vernadite) and insolubilized humic acids (IHA) have been used as binding phases for the remediation of four heavily polluted soils. Vernadite amendments are effective for lead and cadmium remediation, whereas IHA amendments are only effective for copper remediation. In most cases, the labile metal fractions decrease dramatically in amended soils (up to 50%); on the other hand, the amounts of total extracted metal near the point of thermodynamic equilibrium often show no significant difference between the amended soil and the control soil. These results highlight the utility of kinetic fractionation in assessing the efficiency of soil remediation techniques and, more generally, in evaluating trace metal mobility in soils and its potential advantages compared to extraction schemes performed under equilibrium conditions. In the future, this kinetic method could be considerably simplified so as to consume much less time allowing its routine use.

Modeling the solute transport by particle-tracing method with variable weights

Science.gov (United States)

Jiang, J.

2016-12-01

Particle-tracing method is usually used to simulate the solute transport in fracture media. In this method, the concentration at one point is proportional to number of particles visiting this point. However, this method is rather inefficient at the points with small concentration. Few particles visit these points, which leads to violent oscillation or gives zero value of concentration. In this paper, we proposed a particle-tracing method with variable weights. The concentration at one point is proportional to the sum of the weights of the particles visiting it. It adjusts the weight factors during simulations according to the estimated probabilities of corresponding walks. If the weight W of a tracking particle is larger than the relative concentration C at the corresponding site, the tracking particle will be splitted into Int(W/C) copies and each copy will be simulated independently with the weight W/Int(W/C) . If the weight W of a tracking particle is less than the relative concentration C at the corresponding site, the tracking particle will be continually tracked with a probability W/C and the weight will be adjusted to be C. By adjusting weights, the number of visiting particles distributes evenly in the whole range. Through this variable weights scheme, we can eliminate the violent oscillation and increase the accuracy of orders of magnitudes.

Tracing Method with Intra and Inter Protocols Correlation

Directory of Open Access Journals (Sweden)

Marin Mangri

2009-05-01

Full Text Available MEGACO or H.248 is a protocol enabling acentralized Softswitch (or MGC to control MGsbetween Voice over Packet (VoP networks andtraditional ones. To analyze much deeper the realimplementations it is useful to use a tracing systemwith intra and inter protocols correlation. For thisreason in the case of MEGACO-H.248 it is necessaryto find the appropriate method of correlation with allprotocols involved. Starting from Rel4 a separation ofCP (Control Plane and UP (User Plane managementwithin the networks appears. MEGACO protocol playsan important role in the migration to the new releasesor from monolithic platform to a network withdistributed components.

GPU-accelerated ray-tracing for real-time treatment planning

International Nuclear Information System (INIS)

Heinrich, H; Ziegenhein, P; Kamerling, C P; Oelfke, U; Froening, H

2014-01-01

Dose calculation methods in radiotherapy treatment planning require the radiological depth information of the voxels that represent the patient volume to correct for tissue inhomogeneities. This information is acquired by time consuming ray-tracing-based calculations. For treatment planning scenarios with changing geometries and real-time constraints this is a severe bottleneck. We implemented an algorithm for the graphics processing unit (GPU) which implements a ray-matrix approach to reduce the number of rays to trace. Furthermore, we investigated the impact of different strategies of accessing memory in kernel implementations as well as strategies for rapid data transfers between main memory and memory of the graphics device. Our study included the overlapping of computations and memory transfers to reduce the overall runtime using Hyper-Q. We tested our approach on a prostate case (9 beams, coplanar). The measured execution times for a complete ray-tracing range from 28 msec for the computations on the GPU to 99 msec when considering data transfers to and from the graphics device. Our GPU-based algorithm performed the ray-tracing in real-time. The strategies efficiently reduce the time consumption of memory accesses and data transfer overhead. The achieved runtimes demonstrate the viability of this approach and allow improved real-time performance for dose calculation methods in clinical routine.

Dynamic Load Balancing Based on Constrained K-D Tree Decomposition for Parallel Particle Tracing

Energy Technology Data Exchange (ETDEWEB)

Zhang, Jiang; Guo, Hanqi; Yuan, Xiaoru; Hong, Fan; Peterka, Tom

2018-01-01

Particle tracing is a fundamental technique in flow field data visualization. In this work, we present a novel dynamic load balancing method for parallel particle tracing. Specifically, we employ a constrained k-d tree decomposition approach to dynamically redistribute tasks among processes. Each process is initially assigned a regularly partitioned block along with duplicated ghost layer under the memory limit. During particle tracing, the k-d tree decomposition is dynamically performed by constraining the cutting planes in the overlap range of duplicated data. This ensures that each process is reassigned particles as even as possible, and on the other hand the new assigned particles for a process always locate in its block. Result shows good load balance and high efficiency of our method.

A "shotgun" method for tracing the birth locations of sheep from flock tags, applied to scrapie surveillance in Great Britain.

Science.gov (United States)

Birch, Colin P D; Del Rio Vilas, Victor J; Chikukwa, Ambrose C

2010-09-01

Movement records are often used to identify animal sample provenance by retracing the movements of individuals. Here we present an alternative method, which uses the same identity tags and movement records as are used to retrace movements, but ignores individual movement paths. The first step uses a simple query to identify the most likely birth holding for every identity tag included in a database recording departures from agricultural holdings. The second step rejects a proportion of the birth holding locations to leave a list of birth holding locations that are relatively reliable. The method was used to trace the birth locations of sheep sampled for scrapie in abattoirs, or on farm as fallen stock. Over 82% of the sheep sampled in the fallen stock survey died at the holding of birth. This lack of movement may be an important constraint on scrapie transmission. These static sheep provided relatively reliable birth locations, which were used to define criteria for selecting reliable traces. The criteria rejected 16.8% of fallen stock traces and 11.9% of abattoir survey traces. Two tests provided estimates that selection reduced error in fallen stock traces from 11.3% to 3.2%, and in abattoir survey traces from 8.1% to 1.8%. This method generated 14,591 accepted traces of fallen stock from samples taken during 2002-2005 and 83,136 accepted traces from abattoir samples. The absence or ambiguity of flock tag records at the time of slaughter prevented the tracing of 16-24% of abattoir samples during 2002-2004, although flock tag records improved in 2005. The use of internal scoring to generate and evaluate results from the database query, and the confirmation of results by comparison with other database fields, are analogous to methods used in web search engines. Such methods may have wide application in tracing samples and in adding value to biological datasets. Crown Copyright 2010. Published by Elsevier B.V. All rights reserved.

Trace and low concentration co2 removal methods and apparatus utilizing metal organic frameworks

KAUST Repository

Eddaoudi, Mohamed

2016-03-10

In general, this disclosure describes techniques for removing trace and low concentration CO2 from fluids using SIFSIX-n-M MOFs, wherein n is at least two and M is a metal. In some embodiments, the metal is zinc or copper. Embodiments include devices comprising SIFSIX-n-M MOFs for removing CO2 from fluids. In particular, embodiments relate to devices and methods utilizing SIFSIX-n-M MOFs for removing CO2 from fluids, wherein CO2 concentration is trace. Methods utilizing SIFSIX-n-M MOFs for removing CO2 from fluids can occur in confined spaces. SIFSIX-n-M MOFs can comprise bidentate organic ligands. In a specific embodiment, SIFSIX-n-M MOFs comprise pyrazine or dipryidilacetylene ligands.

An improved phase-locked loop method for automatic resonance frequency tracing based on static capacitance broadband compensation for a high-power ultrasonic transducer.

Science.gov (United States)

Dong, Hui-juan; Wu, Jian; Zhang, Guang-yu; Wu, Han-fu

2012-02-01

The phase-locked loop (PLL) method is widely used for automatic resonance frequency tracing (ARFT) of high-power ultrasonic transducers, which are usually vibrating systems with high mechanical quality factor (Qm). However, a heavily-loaded transducer usually has a low Qm because the load has a large mechanical loss. In this paper, a series of theoretical analyses is carried out to detail why the traditional PLL method could cause serious frequency tracing problems, including loss of lock, antiresonance frequency tracing, and large tracing errors. The authors propose an improved ARFT method based on static capacitance broadband compensation (SCBC), which is able to address these problems. Experiments using a generator based on the novel method were carried out using crude oil as the transducer load. The results obtained have demonstrated the effectiveness of the novel method, compared with the conventional PLL method, in terms of improved tracing accuracy (±9 Hz) and immunity to antiresonance frequency tracing and loss of lock.

Development of a new method for hydrogen isotope analysis of trace hydrocarbons in natural gas samples

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Xibin Wang

2016-12-01

Full Text Available A new method had been developed for the analysis of hydrogen isotopic composition of trace hydrocarbons in natural gas samples by using solid phase microextraction (SPME combined with gas chromatography-isotope ratio mass spectrometry (GC/IRMS. In this study, the SPME technique had been initially introduced to achieve the enrichment of trace content of hydrocarbons with low abundance and coupled to GC/IRMS for hydrogen isotopic analysis. The main parameters, including the equilibration time, extraction temperature, and the fiber type, were systematically optimized. The results not only demonstrated that high extraction yield was true but also shows that the hydrogen isotopic fractionation was not observed during the extraction process, when the SPME device fitted with polydimethylsiloxane/divinylbenzene/carbon molecular sieve (PDMS/DVB/CAR fiber. The applications of SPME-GC/IRMS method were evaluated by using natural gas samples collected from different sedimentary basins; the standard deviation (SD was better than 4‰ for reproducible measurements; and also, the hydrogen isotope values from C1 to C9 can be obtained with satisfying repeatability. The SPME-GC/IRMS method fitted with PDMS/DVB/CAR fiber is well suited for the preconcentration of trace hydrocarbons, and provides a reliable hydrogen isotopic analysis for trace hydrocarbons in natural gas samples.

Standardization of Tc-99 by three liquid scintillation counting methods

International Nuclear Information System (INIS)

Wyngaardt, W.M. van; Staden, M.J. van; Lubbe, J.; Simpson, B.R.S.

2014-01-01

The NMISA participated in the international key comparison of the pure beta-emitter Technetium-99, CCRI(II)-K2.Tc-99. The comparison solution was standardized using three methods, namely the TDCR efficiency calculation method, the CIEMAT/NIST efficiency tracing method and the 4π(LS)β–γ coincidence tracing method with Co-60 as tracer. Excellent agreement between results obtained with the three methods confirmed the applicability of the beta spectral shape given by the latest (2011) DDEP evaluation of Tc-99 decay data, rather than the earlier (2004) evaluation. - Highlights: • Activity concentration of Tc-99 solution measured using three LSC methods. • Methods used are TDCR, CNET and 4π(LS)β–γ coincidence tracing. • Beta spectral shape confirmed by agreement between three methods

Standardisation of sup 9 sup 0 Sr, sup 6 sup 3 Ni and sup 5 sup 5 Fe by the 4 pi beta liquid scintillation spectrometry method with sup 3 H-standard efficiency tracing

CERN Document Server

Ceccatelli, A

1999-01-01

The 4 pi beta efficiency tracing liquid scintillation spectrometry method was applied with success, at ENEA, to the activity measurement of pure beta-emitters ( sup 9 sup 0 Sr and sup 6 sup 3 Ni) and electron-capturing nuclides ( sup 5 sup 5 Fe), using sup 3 H as tracer nuclide. The agreement of these measurements in comparison to other national metrology institutes was checked by means of two comparisons, carried out in 1996-1997. Furthermore a study of the stability of the prepared sources was performed and the dependence of the measured activity concentration on the quenching level was analysed. The radionuclides were standardised to a combined standard uncertainty of 0.14% for sup 9 sup 0 Sr, 0.55% for sup 6 sup 3 Ni and 1.18% for sup 5 sup 5 Fe.

TCP Packet Trace Analysis. M.S. Thesis

Science.gov (United States)

Shepard, Timothy J.

1991-01-01

Examination of a trace of packets collected from the network is often the only method available for diagnosing protocol performance problems in computer networks. This thesis explores the use of packet traces to diagnose performance problems of the transport protocol TCP. Unfortunately, manual examination of these traces can be so tedious that effective analysis is not possible. The primary contribution of this thesis is a graphical method of displaying the packet trace which greatly reduce, the tediousness of examining a packet trace. The graphical method is demonstrated by the examination of some packet traces of typical TCP connections. The performance of two different implementations of TCP sending data across a particular network path is compared. Traces many thousands of packets long are used to demonstrate how effectively the graphical method simplifies examination of long complicated traces. In the comparison of the two TCP implementations, the burstiness of the TCP transmitter appeared to be related to the achieved throughput. A method of quantifying this burstiness is presented and its possible relevance to understanding the performance of TCP is discussed.

Quantitative Efficiency Evaluation Method for Transportation Networks

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Jin Qin

2014-11-01

Full Text Available An effective evaluation of transportation network efficiency/performance is essential to the establishment of sustainable development in any transportation system. Based on a redefinition of transportation network efficiency, a quantitative efficiency evaluation method for transportation network is proposed, which could reflect the effects of network structure, traffic demands, travel choice, and travel costs on network efficiency. Furthermore, the efficiency-oriented importance measure for network components is presented, which can be used to help engineers identify the critical nodes and links in the network. The numerical examples show that, compared with existing efficiency evaluation methods, the network efficiency value calculated by the method proposed in this paper can portray the real operation situation of the transportation network as well as the effects of main factors on network efficiency. We also find that the network efficiency and the importance values of the network components both are functions of demands and network structure in the transportation network.

Study on method of characteristics based on cell modular ray tracing

International Nuclear Information System (INIS)

Tang Chuntao; Zhang Shaohong

2009-01-01

To address the issue of accurately solving neutron transport problem in complex geometry, method of characteristics (MOC) is studied in this paper, and a quite effective and memory saving cell modular ray tracing (CMRT) method is developed and related angle discretization and boundary condition handling issues are discussed. A CMRT based MOC code-PEACH is developed and tested against C5G7 MOX benchmark problem. Numerical results demonstrate that PEACH can give excellent accuracy for both k eff and pin power distribution for neutron transport problem. (authors)

Determination of trace amounts of Brown HT as a food dye by a CPE-scanometry method

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A. Shokrollahi

2017-01-01

Full Text Available In this study, trace amounts of Brown HT were extracted, pre-concentrated and determined by cloud point extraction-scanometry (CPE-scanometry as a simple, fast and inexpensive method. The procedure is based on CPE of Brown HT from an aqueous solution, diluting the extracted surfactant-rich phase with ethanol to 500 μL, transferring the appropriate volume to Plexiglas® cells and scanning the cells. Then, the colour of each cell was analyzed by software written in visual basic (VB 6 into red, green and blue values. Effective parameters for the extraction efficiency, such as the pH of the system, the concentration of surfactant, the equilibration temperature and equilibration time, were investigated and optimized. Under optimal conditions, the calibration curve was linear in the range of 0.06–2.60 mg L−1. The detection limit of the proposed method was 0.04 mg L−1. In addition, the effects of some foreign species, including cations, anions and dyes, were investigated. The method was applied successfully for the determination of Brown HT in some water samples.

Official Methods for the Determination of Minerals and Trace Elements in Infant Formula and Milk Products: A Review.

Science.gov (United States)

Poitevin, Eric

2016-01-01

The minerals and trace elements that account for about 4% of total human body mass serve as materials and regulators in numerous biological activities in body structure building. Infant formula and milk products are important sources of endogenic and added minerals and trace elements and hence, must comply with regulatory as well as nutritional and safety requirements. In addition, reliable analytical data are necessary to support product content and innovation, health claims, or declaration and specific safety issues. Adequate analytical platforms and methods must be implemented to demonstrate both the compliance and safety assessment of all declared and regulated minerals and trace elements, especially trace-element contaminant surveillance. The first part of this paper presents general information on the mineral composition of infant formula and milk products and their regulatory status. In the second part, a survey describes the main techniques and related current official methods determining minerals and trace elements in infant formula and milk products applied for by various international organizations (AOAC INTERNATIONAL, the International Organization for Standardization, the International Dairy Federation, and the European Committe for Standardization). The third part summarizes method officialization activities by Stakeholder Panels on Infant Formula and Adult Nutritionals and Stakeholder Panel on Strategic Food Analytical Methods. The final part covers a general discussion focusing on analytical gaps and future trends in inorganic analysis that have been applied for in infant formula and milk-based products.

Modeling UV Radiation Feedback from Massive Stars. I. Implementation of Adaptive Ray-tracing Method and Tests

Science.gov (United States)

Kim, Jeong-Gyu; Kim, Woong-Tae; Ostriker, Eve C.; Skinner, M. Aaron

2017-12-01

We present an implementation of an adaptive ray-tracing (ART) module in the Athena hydrodynamics code that accurately and efficiently handles the radiative transfer involving multiple point sources on a three-dimensional Cartesian grid. We adopt a recently proposed parallel algorithm that uses nonblocking, asynchronous MPI communications to accelerate transport of rays across the computational domain. We validate our implementation through several standard test problems, including the propagation of radiation in vacuum and the expansions of various types of H II regions. Additionally, scaling tests show that the cost of a full ray trace per source remains comparable to that of the hydrodynamics update on up to ∼ {10}3 processors. To demonstrate application of our ART implementation, we perform a simulation of star cluster formation in a marginally bound, turbulent cloud, finding that its star formation efficiency is 12% when both radiation pressure forces and photoionization by UV radiation are treated. We directly compare the radiation forces computed from the ART scheme with those from the M 1 closure relation. Although the ART and M 1 schemes yield similar results on large scales, the latter is unable to resolve the radiation field accurately near individual point sources.

Determination of trace lithium in uranium compounds by adsorption on activated alumina using a micro-column method.

Science.gov (United States)

Luo, Ming-Biao; Li, Bo-Ping; Yang, Zhi; Liu, Wei; Sun, Yu-Zhen

2008-08-01

A novel method using a micro-column packed with active alumina as solid phase was proposed for separation of trace lithium from uranium compounds prior to determination. The method is based on a preliminary chromatographic separation of the total amount of uranium. This separation involves passing the solution containing sodium carbonate through active alumina and then eluting the trace lithium retained by the solid phase with a solution of sulfuric acid. Two modes, off-line and on-line micro-column preconcentration, were performed. In conjunction with atomic absorption spectrometry, this on-line preconcentration technique allows a determination of lithium at 10(-9) level. Both off-line and on-line mode operation conditions were investigated in separation and determination of trace lithium by micro-column method (length of column bed, flow rate, etc.). The adsorption capacity of activated alumina was found to be 343 microg g(-1) for lithium. Under the optimal operation condition, the detection limit (DL) of on-line preconcentration corresponding to three times the standard deviation of the blank (S/N = 3) was found to be 1.3 ng mL(-1) and the RSD of this method is 3.32% (n = 5). The on-line calibration graph was linear over the range 20 - 200 ng mL(-1). A good preconcentration factor 820 was achieved by experiment under the on-line mode. The developed method was applied to the analysis of trace lithium in nuclear grade uranium compounds.

Vertex shading of the three-dimensional model based on ray-tracing algorithm

Science.gov (United States)

Hu, Xiaoming; Sang, Xinzhu; Xing, Shujun; Yan, Binbin; Wang, Kuiru; Dou, Wenhua; Xiao, Liquan

2016-10-01

Ray Tracing Algorithm is one of the research hotspots in Photorealistic Graphics. It is an important light and shadow technology in many industries with the three-dimensional (3D) structure, such as aerospace, game, video and so on. Unlike the traditional method of pixel shading based on ray tracing, a novel ray tracing algorithm is presented to color and render vertices of the 3D model directly. Rendering results are related to the degree of subdivision of the 3D model. A good light and shade effect is achieved by realizing the quad-tree data structure to get adaptive subdivision of a triangle according to the brightness difference of its vertices. The uniform grid algorithm is adopted to improve the rendering efficiency. Besides, the rendering time is independent of the screen resolution. In theory, as long as the subdivision of a model is adequate, cool effects as the same as the way of pixel shading will be obtained. Our practical application can be compromised between the efficiency and the effectiveness.

Development of Extended Ray-tracing method including diffraction, polarization and wave decay effects

Science.gov (United States)

Yanagihara, Kota; Kubo, Shin; Dodin, Ilya; Nakamura, Hiroaki; Tsujimura, Toru

2017-10-01

Geometrical Optics Ray-tracing is a reasonable numerical analytic approach for describing the Electron Cyclotron resonance Wave (ECW) in slowly varying spatially inhomogeneous plasma. It is well known that the result with this conventional method is adequate in most cases. However, in the case of Helical fusion plasma which has complicated magnetic structure, strong magnetic shear with a large scale length of density can cause a mode coupling of waves outside the last closed flux surface, and complicated absorption structure requires a strong focused wave for ECH. Since conventional Ray Equations to describe ECW do not have any terms to describe the diffraction, polarization and wave decay effects, we can not describe accurately a mode coupling of waves, strong focus waves, behavior of waves in inhomogeneous absorption region and so on. For fundamental solution of these problems, we consider the extension of the Ray-tracing method. Specific process is planned as follows. First, calculate the reference ray by conventional method, and define the local ray-base coordinate system along the reference ray. Then, calculate the evolution of the distributions of amplitude and phase on ray-base coordinate step by step. The progress of our extended method will be presented.

Robust Requirements Tracing via Internet Search Technology: Improving an IV and V Technique. Phase 2

Science.gov (United States)

Hayes, Jane; Dekhtyar, Alex

2004-01-01

There are three major objectives to this phase of the work. (1) Improvement of Information Retrieval (IR) methods for Independent Verification and Validation (IV&V) requirements tracing. Information Retrieval methods are typically developed for very large (order of millions - tens of millions and more documents) document collections and therefore, most successfully used methods somewhat sacrifice precision and recall in order to achieve efficiency. At the same time typical IR systems treat all user queries as independent of each other and assume that relevance of documents to queries is subjective for each user. The IV&V requirements tracing problem has a much smaller data set to operate on, even for large software development projects; the set of queries is predetermined by the high-level specification document and individual requirements considered as query input to IR methods are not necessarily independent from each other. Namely, knowledge about the links for one requirement may be helpful in determining the links of another requirement. Finally, while the final decision on the exact form of the traceability matrix still belongs to the IV&V analyst, his/her decisions are much less arbitrary than those of an Internet search engine user. All this suggests that the information available to us in the framework of the IV&V tracing problem can be successfully leveraged to enhance standard IR techniques, which in turn would lead to increased recall and precision. We developed several new methods during Phase II; (2) IV&V requirements tracing IR toolkit. Based on the methods developed in Phase I and their improvements developed in Phase II, we built a toolkit of IR methods for IV&V requirements tracing. The toolkit has been integrated, at the data level, with SAIC's SuperTracePlus (STP) tool; (3) Toolkit testing. We tested the methods included in the IV&V requirements tracing IR toolkit on a number of projects.

Nuclear traces in glass

International Nuclear Information System (INIS)

Segovia A, M. de N.

1978-01-01

The charged particles produce, in dielectric materials, physical and chemical effects which make evident the damaged zone along the trajectory of the particle. This damaged zone is known as the latent trace. The latent traces can be enlarged by an etching of the detector material. This treatment attacks preferently the zones of the material where the charged particles have penetrated, producing concavities which can be observed through a low magnification optical microscope. These concavities are known as developed traces. In this work we describe the glass characteristics as a detector of the fission fragments traces. In the first chapter we present a summary of the existing basic theories to explain the formation of traces in solids. In the second chapter we describe the etching method used for the traces development. In the following chapters we determine some chatacteristics of the traces formed on the glass, such as: the development optimum time; the diameter variation of the traces and their density according to the temperature variation of the detector; the glass response to a radiation more penetrating than that of the fission fragments; the distribution of the developed traces and the existing relation between this ditribution and the fission fragments of 252 Cf energies. The method which has been used is simple and cheap and can be utilized in laboratories whose resources are limited. The commercial glass which has been employed allows the registration of the fission fragments and subsequently the realization of experiments which involve the counting of the traces as well as the identification of particles. (author)

Efficiency profile method to study the hit efficiency of drift chambers

International Nuclear Information System (INIS)

Abyzov, A.; Bel'kov, A.; Lanev, A.; Spiridonov, A.; Walter, M.; Hulsbergen, W.

2002-01-01

A method based on the usage of efficiency profile is proposed to estimate the hit efficiency of drift chambers with a large number of channels. The performance of the method under real conditions of the detector operation has been tested analysing the experimental data from the HERA-B drift chambers

Method to determine trace elements in water samples by neutron activation analysis

International Nuclear Information System (INIS)

Kueppers, G.; Erdtmann, G.

1981-05-01

For the determination of trace elements in water by neutron activation analysis irradiation porcedures and chemical separation procedures have been developed. Irradiation in melted quarz glass ampoules in the presence of a platinum wire (for recombination of the oxyhydrogen gas produced by radiolysis) proved successfull with different variants of the irradiation methods, as long irradiation periods without pressure build-up could be achieved. Possible falsifications of the analysis results were investigated in detail (losses by absorption on vessel walls etc.). The irradiated samples can be measured directly with a gamma ray spectrometer and from the radionuclides found the trace element contents may be calculated. More sensitive determinations are possible if the radionuclides are chemically separated. Procedures for removing the matrix activities, for the separation of the radionuclides in groups of elements and for the isolation of single elements have been developed. For especially sensitive determination of some elements selective separation procedures for antimony, cadmium, selenium, mercury and uranium have been developed. The analytical procedures described have been applied to trace element determinations in river water, glacier ice and water solutions from technical processes. (orig./RB) [de

Intradermal Alcian-Blue Injection Method to Trace Acupuncture Meridians

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Baeckkyoung Sung

2008-06-01

Full Text Available Objective : In this article, we report on the intradermal Alcian blue staining method for tracing the meridians of acupuncture. Methods : 1% Alcian blue solution was injected into acupoints by using a 0.5mL insulin syringe with a 31-gauge needle, then the skin was incised and was observed under a stereoscopic microscope. The specimens were examined by using immunohistochemical methods and were observed under a confocal laser scanning microscope. Results : A threadlike structure, which was visualized with Alcian blue, existed in dermis layer and proceeded to hypodermis. In this structure, characteristic alignments of rod- shaped nuclei and 1-2μm sized DNA granules were observed. Furthermore, abundant blood capillary plexuses, peripheral nerve endings, and a corpusclelike structure(about 300μm in diameter were visualized in the skin tissues of acupoints. Conclusion : It was concluded that the specific threadlike and corpuscle-like structures corresponded to superficial Bonghan duct and corpuscle, respectively.

Utilization of macrominerals and trace elements in pregnant heifers with distinct feed efficiencies.

Science.gov (United States)

Dias, R S; Montanholi, Y R; Lopez, S; Smith, B; Miller, S P; France, J

2016-07-01

The objective of the study was to evaluate utilization of dietary minerals and trace elements in pregnant heifers with distinct residual feed intakes (RFI). Feed intake, body weight (BW), and body composition traits were recorded in 36 crossbred heifers over a period of 37 wk, starting shortly after weaning at 8.3 (0.10; standard deviation) mo of age with an average BW of 276 (7.8) kg. Both BW and body composition were monitored regularly throughout the study, whereas individual feed intake was assessed during the last 84 d of the trial. Data recorded were used to calculate RFI for each heifer. Heifers were ranked based on RFI and assigned to high (n=14) or low (n=10) RFI groups. After the RFI study, 24 selected heifers [age 18.2 (0.14) mo; 87.5 (4.74) d in gestation; 497 (8.5) kg of BW] were used in an indirect digestibility trial (lignin as internal marker). Heifers were fed a ration containing corn silage, haylage, and a mineral premix in which Ca, P, K, Na, Mg, S, Cu, Fe, Mn, Mo, Se, Zn, and Co were provided in the diet according to National Research Council requirements of pregnant replacement heifers. The digestibility trial lasted 1 wk, during which samples of feces were gathered twice daily, and blood and liver biopsy samples were collected on the last day. We noted no significant differences between low- and high-RFI heifers in dry matter digestibility. Apparent absorption of Cu, Zn, and Mn was increased in heifers with low RFI, and apparent absorption of Co tended to be greater for these animals. Concentrations of macrominerals and trace elements in serum of pregnant heifers were similar for both groups except for Se, which was increased in the serum of low-RFI heifers. Liver concentrations of Cu, Fe, Mn, Mo, Se, and Zn did not differ between low- and high-RFI heifers. In conclusion, whereas improved absorption of some trace elements (Cu, Zn, Mn, and Co) and increased Se serum concentration appear to be associated with superior feed efficiency in pregnant

Mathematic models for a ray tracing method and its applications in wireless optical communications.

Science.gov (United States)

Zhang, Minglun; Zhang, Yangan; Yuan, Xueguang; Zhang, Jinnan

2010-08-16

This paper presents a new ray tracing method, which contains a whole set of mathematic models, and its validity is verified by simulations. In addition, both theoretical analysis and simulation results show that the computational complexity of the method is much lower than that of previous ones. Therefore, the method can be used to rapidly calculate the impulse response of wireless optical channels for complicated systems.

76 FR 21673 - Alternative Efficiency Determination Methods and Alternate Rating Methods

Science.gov (United States)

2011-04-18

... EERE-2011-BP-TP-00024] RIN 1904-AC46 Alternative Efficiency Determination Methods and Alternate Rating Methods AGENCY: Office of Energy Efficiency and Renewable Energy, Department of Energy. ACTION: Notice of... and data related to the use of computer simulations, mathematical methods, and other alternative...

A solid-phase extraction method for analyzing trace amounts of polychlorinated dibenzo-p-dioxins and dibenzofurans in waste water

Directory of Open Access Journals (Sweden)

Hye-Sung Cho

2011-03-01

Full Text Available The Korean government has regulated emission of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fsin waste water of manufacturing facilities producing chlorinated compounds since 2009. As this regulation is expected to bereinforced in 2013 to 50 pg I-TEQ/L, a large sample volume is required for the analysis of trace amounts of PCDD/Fs in wastewater. Liquid-liquid extraction (LLE is used to extract PCDD/Fs from aqueous samples; however, its low efficiency makes itinadequate for analyzing large sample volumes. Herein, we present a disk-type solid-phase extraction (SPE method for the analysisof dioxin at a part per quadrillion level in waste water. This SPE system contains airtight glass covers with a decompressionpump, which enables continuous semi-automated extraction. Small (0.5 L and large (7 L samples were extracted using LLE andSPE methods, respectively. The method detection limits (MDLs were 0.001−0.25 and 0.015−4.1 pg I-TEQ/L for the SPE andLLE methods, respectively. The concentrations of detected congeners with both methods were similar. However, the concentrationsof several congeners that were not detected with the LLE method were quantified using the SPE method

Classification of conductance traces with recurrent neural networks

Science.gov (United States)

Lauritzen, Kasper P.; Magyarkuti, András; Balogh, Zoltán; Halbritter, András; Solomon, Gemma C.

2018-02-01

We present a new automated method for structural classification of the traces obtained in break junction experiments. Using recurrent neural networks trained on the traces of minimal cross-sectional area in molecular dynamics simulations, we successfully separate the traces into two classes: point contact or nanowire. This is done without any assumptions about the expected features of each class. The trained neural network is applied to experimental break junction conductance traces, and it separates the classes as well as the previously used experimental methods. The effect of using partial conductance traces is explored, and we show that the method performs equally well using full or partial traces (as long as the trace just prior to breaking is included). When only the initial part of the trace is included, the results are still better than random chance. Finally, we show that the neural network classification method can be used to classify experimental conductance traces without using simulated results for training, but instead training the network on a few representative experimental traces. This offers a tool to recognize some characteristic motifs of the traces, which can be hard to find by simple data selection algorithms.

Radiotracer investigation of the cold-vapour atomic absorption method of analysis for trace mercury

International Nuclear Information System (INIS)

Stuart, D.C.

1978-01-01

Because of certain problems found in application of the atomic absorption method for trace analysis of mercury, a careful check of the procedures used was undertaken, with radiotracer mercury to facilitate the investigation. The results obtained, in conjunction with those of sample ashing procedures, indicate that the method is less straightforward than its simplicity suggests. (Auth.)

Testing Linear Temporal Logic Formulae on Finite Execution Traces

Science.gov (United States)

Havelund, Klaus; Rosu, Grigore; Norvig, Peter (Technical Monitor)

2001-01-01

We present an algorithm for efficiently testing Linear Temporal Logic (LTL) formulae on finite execution traces. The standard models of LTL are infinite traces, reflecting the behavior of reactive and concurrent systems which conceptually may be continuously alive. In most past applications of LTL. theorem provers and model checkers have been used to formally prove that down-scaled models satisfy such LTL specifications. Our goal is instead to use LTL for up-scaled testing of real software applications. Such tests correspond to analyzing the conformance of finite traces against LTL formulae. We first describe what it means for a finite trace to satisfy an LTL property. We then suggest an optimized algorithm based on transforming LTL formulae. The work is done using the Maude rewriting system. which turns out to provide a perfect notation and an efficient rewriting engine for performing these experiments.

Comparative Study of Trace Metrics between Bibliometrics and Patentometrics

Directory of Open Access Journals (Sweden)

Fred Y. Ye

2016-06-01

Full Text Available Purpose: To comprehensively evaluate the overall performance of a group or an individual in both bibliometrics and patentometrics. Design/methodology/approach: Trace metrics were applied to the top 30 universities in the 2014 Academic Ranking of World Universities (ARWU — computer sciences, the top 30 ESI highly cited papers in the computer sciences field in 2014, as well as the top 30 assignees and the top 30 most cited patents in the National Bureau of Economic Research (NBER computer hardware and software category. Findings: We found that, by applying trace metrics, the research or marketing impact efficiency, at both group and individual levels, was clearly observed. Furthermore, trace metrics were more sensitive to the different publication-citation distributions than the average citation and h-index were. Research limitations: Trace metrics considered publications with zero citations as negative contributions. One should clarify how he/she evaluates a zero-citation paper or patent before applying trace metrics. Practical implications: Decision makers could regularly examinine the performance of their university/company by applying trace metrics and adjust their policies accordingly. Originality/value: Trace metrics could be applied both in bibliometrics and patentometrics and provide a comprehensive view. Moreover, the high sensitivity and unique impact efficiency view provided by trace metrics can facilitate decision makers in examining and adjusting their policies.

Toward cost-efficient sampling methods

Science.gov (United States)

Luo, Peng; Li, Yongli; Wu, Chong; Zhang, Guijie

2015-09-01

The sampling method has been paid much attention in the field of complex network in general and statistical physics in particular. This paper proposes two new sampling methods based on the idea that a small part of vertices with high node degree could possess the most structure information of a complex network. The two proposed sampling methods are efficient in sampling high degree nodes so that they would be useful even if the sampling rate is low, which means cost-efficient. The first new sampling method is developed on the basis of the widely used stratified random sampling (SRS) method and the second one improves the famous snowball sampling (SBS) method. In order to demonstrate the validity and accuracy of two new sampling methods, we compare them with the existing sampling methods in three commonly used simulation networks that are scale-free network, random network, small-world network, and also in two real networks. The experimental results illustrate that the two proposed sampling methods perform much better than the existing sampling methods in terms of achieving the true network structure characteristics reflected by clustering coefficient, Bonacich centrality and average path length, especially when the sampling rate is low.

Evaluation of trace elements distribution in water, sediment, soil and cassava plant in Muria peninsula environment by NAA method

International Nuclear Information System (INIS)

Muryono, H.; Sumining; Agus Taftazani; Kris Tri Basuki; Sukarman, A.

1999-01-01

The evaluation of trace elements distribution in water, sediment, soil and cassava plant in Muria peninsula by NAA method were done. The nuclear power plant (NPP) and the coal power plant (CPP) will be built in Muria peninsula, so, the Muria peninsula is an important site for samples collection and monitoring of environment. River-water, sediment, dryland-soil and cassava plant were choosen as specimens samples from Muria peninsula environment. The analysis result of trace elements were used as a contributed data for environment monitoring before and after NPP was built. The trace elements in specimens of river-water, sediment, dryland-soil and cassava plant samples were analyzed by INAA method. It was found that the trace elements distribution were not evenly distributed. Percentage of trace elements distribution in river-water, sediment, dryland-soil and cassava leaves were 0.00026-0.037% in water samples, 0.49-62.7% in sediment samples, 36.29-99.35% in soil samples and 0.21-99.35% in cassava leaves. (author)

Evaluation of trace elements distribution in water, sediment, soil and cassava plant in Muria peninsula environment by NAA method

Energy Technology Data Exchange (ETDEWEB)

Muryono, H.; Sumining; Agus Taftazani; Kris Tri Basuki; Sukarman, A. [Yogyakarta Nuclear Research Center, Yogyakarta (Indonesia)

1999-10-01

The evaluation of trace elements distribution in water, sediment, soil and cassava plant in Muria peninsula by NAA method were done. The nuclear power plant (NPP) and the coal power plant (CPP) will be built in Muria peninsula, so, the Muria peninsula is an important site for samples collection and monitoring of environment. River-water, sediment, dryland-soil and cassava plant were choosen as specimens samples from Muria peninsula environment. The analysis result of trace elements were used as a contributed data for environment monitoring before and after NPP was built. The trace elements in specimens of river-water, sediment, dryland-soil and cassava plant samples were analyzed by INAA method. It was found that the trace elements distribution were not evenly distributed. Percentage of trace elements distribution in river-water, sediment, dryland-soil and cassava leaves were 0.00026-0.037% in water samples, 0.49-62.7% in sediment samples, 36.29-99.35% in soil samples and 0.21-99.35% in cassava leaves. (author)

Abstracts book of 4. Poznan Analytical Seminar on Modern Methods of Sample Preparation and Trace Amounts Determination of Elements

International Nuclear Information System (INIS)

1995-01-01

The 4. Poznan Analytical Seminar on Modern Methods of Sample Preparation and Trace Amounts Determination of Elements has been held in Poznan 27-28 April 1995. The new versions of analytical methods have been presented for quantitative determination of trace elements in biological, environmental and geological materials. Also the number of special techniques for sample preparation enables achievement the best precision of analytical results have been shown and discussed

Robust Adaptive Photon Tracing using Photon Path Visibility

DEFF Research Database (Denmark)

Hachisuka, Toshiya; Jensen, Henrik Wann

2011-01-01

We present a new adaptive photon tracing algorithm which can handle illumination settings that are considered difficult for photon tracing approaches such as outdoor scenes, close-ups of a small part of an illuminated region, and illumination coming through a small gap. The key contribution in our...... algorithm is the use of visibility of photon path as the importance function which ensures that our sampling algorithm focuses on paths that are visible from the given viewpoint. Our sampling algorithm builds on two recent developments in Markov chain Monte Carlo methods: adaptive Markov chain sampling...... and replica exchange. Using these techniques, each photon path is adaptively mutated and it explores the sampling space efficiently without being stuck at a local peak of the importance function. We have implemented this sampling approach in the progressive photon mapping algorithm which provides visibility...

Corporate Accounting Policy Efficiency Improvement

Directory of Open Access Journals (Sweden)

Elena K. Vorobei

2013-01-01

Full Text Available The article is focused on the issues of efficient use of different methods of tax accounting for the optimization of income tax expenses and their consolidation in corporate accounting policy. The article makes reasoned conclusions, concerning optimal selection of depreciation methods for tax and bookkeeping accounting and their consolidation in corporate accounting policy and consolidation of optimal methods of cost recovery in production, considering business environment. The impact of the selected methods on corporate income tax rates and corporate property tax rates was traced and tax recovery was estimated.

An automatic scaling method for obtaining the trace and parameters from oblique ionogram based on hybrid genetic algorithm

Science.gov (United States)

Song, Huan; Hu, Yaogai; Jiang, Chunhua; Zhou, Chen; Zhao, Zhengyu; Zou, Xianjian

2016-12-01

Scaling oblique ionogram plays an important role in obtaining ionospheric structure at the midpoint of oblique sounding path. The paper proposed an automatic scaling method to extract the trace and parameters of oblique ionogram based on hybrid genetic algorithm (HGA). The extracted 10 parameters come from F2 layer and Es layer, such as maximum observation frequency, critical frequency, and virtual height. The method adopts quasi-parabolic (QP) model to describe F2 layer's electron density profile that is used to synthesize trace. And it utilizes secant theorem, Martyn's equivalent path theorem, image processing technology, and echoes' characteristics to determine seven parameters' best fit values, and three parameter's initial values in QP model to set up their searching spaces which are the needed input data of HGA. Then HGA searches the three parameters' best fit values from their searching spaces based on the fitness between the synthesized trace and the real trace. In order to verify the performance of the method, 240 oblique ionograms are scaled and their results are compared with manual scaling results and the inversion results of the corresponding vertical ionograms. The comparison results show that the scaling results are accurate or at least adequate 60-90% of the time.

Trace-based post-silicon validation for VLSI circuits

CERN Document Server

Liu, Xiao

2014-01-01

This book first provides a comprehensive coverage of state-of-the-art validation solutions based on real-time signal tracing to guarantee the correctness of VLSI circuits.  The authors discuss several key challenges in post-silicon validation and provide automated solutions that are systematic and cost-effective.  A series of automatic tracing solutions and innovative design for debug (DfD) techniques are described, including techniques for trace signal selection for enhancing visibility of functional errors, a multiplexed signal tracing strategy for improving functional error detection, a tracing solution for debugging electrical errors, an interconnection fabric for increasing data bandwidth and supporting multi-core debug, an interconnection fabric design and optimization technique to increase transfer flexibility and a DfD design and associated tracing solution for improving debug efficiency and expanding tracing window. The solutions presented in this book improve the validation quality of VLSI circuit...

Tracing a planar algebraic curve

International Nuclear Information System (INIS)

Chen Falai; Kozak, J.

1994-09-01

In this paper, an algorithm that determines a real algebraic curve is outlined. Its basic step is to divide the plane into subdomains that include only simple branches of the algebraic curve without singular points. Each of the branches is then stably and efficiently traced in the particular subdomain. Except for the tracing, the algorithm requires only a couple of simple operations on polynomials that can be carried out exactly if the coefficients are rational, and the determination of zeros of several polynomials of one variable. (author). 5 refs, 4 figs

[Ideas and methods on efficient screening of traditional medicines for anti-osteoporosis activity based on M-Act/Tox integrated evaluation using zebrafish].

Science.gov (United States)

Wang, Mo; Ling, Jie; Chen, Ying; Song, Jie; Sun, E; Shi, Zi-Qi; Feng, Liang; Jia, Xiao-Bin; Wei, Ying-Jie

2017-11-01

The increasingly apparent liver injury problems of bone strengthening Chinese medicines have brought challenges for clinical application, and it is necessary to consider both effectiveness and safety in screening anti-osteoporosis Chinese medicines. Metabolic transformation is closely related to drug efficacy and toxicity, so it is significant to comprehensively consider metabolism-action/toxicity(M-Act/Tox) for screening anti-osteoporosis Chinese medicines. The current evaluation models and the number of compounds(including metabolites) severely restrict efficient screening in vivo. By referring to previous relevant research and domestic and abroad literature, zebrafish M-Act/Tox integrative method was put forward for efficiently screening anti-osteoporosis herb medicines, which has organically integrated zebrafish metabolism model, osteoporosis model and toxicity evaluation method. This method can break through the bottleneck and blind spots that trace compositions can't achieve efficient and integrated in vivo evaluation, and realize both efficient and comprehensive screening on anti-osteoporosis traditional medicines based on in vivo process taking both safety and effectiveness into account, which is significant to accelerate discovery of effective and safe innovative traditional Chinese medicines for osteoporosis. Copyright© by the Chinese Pharmaceutical Association.

Trace impurities in coal by wet chemical methods

International Nuclear Information System (INIS)

Pollock, E.N.

1975-01-01

In determining trace elements in coal by wet chemical methods, conventional atomic absorption spectroscopy (AAS) was used to determine Li, Be, V, Cr, Mn, Co, Ni, Cu, Zn, Ag, Cd, and Pb after dry ashing and acid dissolutions. A graphite furnace accessory was used for the flameless AAS determination of Bi, Se, Sn, Te, Be, Pb, As, Cd, Cr, Sb, and Ge. Mercury can be determined by flameless AAS after oxygen bomb combustion. Arsenic and antimony can be determined as their hydrides by AAS after low temperature ashing. Germanium, tin, bismuth, and tellurium can be determined as their hydrides by AAS after high temperature ashing. Selenium can be determined as its hydride by AAS after a special combustion procedure or after oxygen bomb combustion. Fluorine can be determined by specific ion analysis after oxygen bomb combustion. Boron can be determined colorimetrically. (U.S.)

An efficient sodium citrate-promoted synthetic method for the preparation of AuNPs@mesoSiO2 for surface enhanced Raman spectroscopy in the detection of diluted blood

Directory of Open Access Journals (Sweden)

Yun Zou

2017-12-01

Full Text Available We report on a novel, green, and efficient organically synthetic method for the preparation of gold nanoparticles embedded in mesoporous silica (AuNPs@mesoSiO2. AuNPs@mesoSiO2 prepared by one-pot synthesis method using sodium citrate as the key reactant was applied for surface enhanced Raman spectroscopy (SERS application in the analysis of diluted blood traces. The synthesized nanoparticles are of high quality, as characterized by use of X-ray diffraction, scanning electron microscopy and transmission electron microscopy. They exhibit high surface areas (170.18–883 m2/g and significant SERS enhancement. Detection of diluted blood (v/v, 1:50 traces through AuNPs@mesoSiO2 enhanced SERS is demonstrated, which has not been studied in previous literature. The combination of the SERS and AuNPs@mesoSiO2 would be a valuable tool for forensic investigation. Keywords: Gold nanoparticles, Mesoporous materials, Synthesis, SERS, Blood trace

Modified emission-transmission method for determining trace elements in solid samples using the XRF techniques

International Nuclear Information System (INIS)

Poblete, V.; Alvarez, M.; Hermosilla, M.

2000-01-01

This is a study of an analysis of trace elements in medium thick solid samples, by the modified transmission emission method, using the energy dispersion X-ray fluorescence technique (EDXRF). The effects of absorption and reinforcement are the main disadvantages of the EDXRF technique for the quantitative analysis of bigger elements and trace elements in solid samples. The implementation of this method and its application to a variety of samples was carried out using an infinitely thick multi-element white sample that calculates the correction factors by absorbing all the analytes in the sample. The discontinuities in the masic absorption coefficients versus energies association for each element, with medium thick and homogenous samples, are analyzed and corrected. A thorough analysis of the different theoretical and test variables are proven by using real samples, including certified material with known concentration. The simplicity of the calculation method and the results obtained show the method's major precision, with possibilities for the non-destructive routine analysis of different solid samples, using the EDXRF technique (author)

Anaerobic digestion of thermal pre-treated emulsified slaughterhouse wastes (TESW): Effect of trace element limitation on process efficiency and sludge metabolic properties.

Science.gov (United States)

Eftaxias, Alexandros; Diamantis, Vasileios; Aivasidis, Alexandros

2018-06-01

Slaughterhouse solid wastes, characterized by a high lipid content, are considered a valuable resource for energy production by means of anaerobic digestion technologies. Aim of this study was to examine the effect of trace element limitation on the mesophilic anaerobic digestion of thermally pre-treated emulsified slaughterhouse wastes (TESW). Under two distinct experimental periods (Period I - low and Period II - high trace element dosage respectively) a CSTR with sludge recirculation was operated at increasing organic loading rate (OLR) from 1.5 to 10 g L -1  d -1 . Under optimum conditions, COD removal was higher than 96%, biogas yield equal to 0.53 L g -1  COD feed and the biogas methane content 77%. Trace element limitation however, resulted in a dramatic decline in process efficiency, with VFA accumulation and events of extreme sludge flotation, despite that the soluble concentration of Ni, Co and Mo were between 12 and 28 μg L -1 . This is indicative of mass transfer limitations caused by lipids adsorption onto the anaerobic biomass. Copyright © 2018 Elsevier Ltd. All rights reserved.

A new method to analyze copolymer based superplasticizer traces in cement leachates.

Science.gov (United States)

Guérandel, Cyril; Vernex-Loset, Lionel; Krier, Gabriel; De Lanève, Michel; Guillot, Xavier; Pierre, Christian; Muller, Jean François

2011-03-15

Enhancing the flowing properties of fresh concrete is a crucial step for cement based materials users. This is done by adding polymeric admixtures. Such additives have enabled to improve final mechanicals properties and the development of new materials like high performance or self compacting concrete. Like this, the superplasticizers are used in almost cement based materials, in particular for concrete structures that can have a potential interaction with drinking water. It is then essential to have suitable detection techniques to assess whether these organic compounds are dissolved in water after a leaching process or not. The main constituent of the last generation superplasticizer is a PolyCarboxylate-Ester copolymer (PCE), in addition this organic admixture contains polyethylene oxide (free PEO) which constitutes a synthesis residue. Numerous analytical methods are available to characterize superplasticizer content. Although these techniques work well, they do not bring suitable detection threshold to analyze superplasticizer traces in solution with high mineral content such as leachates of hardened cement based materials formulated with superplasticizers. Moreover those techniques do not enable to distinguish free PEO from PCE in the superplasticizer. Here we discuss two highly sensitive analytical methods based on mass spectrometry suitable to perform a rapid detection of superplasticizer compounds traces in CEM I cement paste leachates: MALDI-TOF mass spectrometry, is used to determine the free PEO content in the leachate. However, industrial copolymers (such as PCE) are characterized by high molecular weight and polymolecular index. These two parameters lead to limitation concerning analysis of copolymers by MALDI-TOFMS. In this study, we demonstrate how pyrolysis and a Thermally assisted Hydrolysis/Methylation coupled with a triple-quadrupole mass spectrometer, provides good results for the detection of PCE copolymer traces in CEM I cement paste

Towards Cost-efficient Sampling Methods

OpenAIRE

Peng, Luo; Yongli, Li; Chong, Wu

2014-01-01

The sampling method has been paid much attention in the field of complex network in general and statistical physics in particular. This paper presents two new sampling methods based on the perspective that a small part of vertices with high node degree can possess the most structure information of a network. The two proposed sampling methods are efficient in sampling the nodes with high degree. The first new sampling method is improved on the basis of the stratified random sampling method and...

Ar39 Detection at the 10-16 Isotopic Abundance Level with Atom Trap Trace Analysis

Science.gov (United States)

Jiang, W.; Williams, W.; Bailey, K.; Davis, A. M.; Hu, S.-M.; Lu, Z.-T.; O'Connor, T. P.; Purtschert, R.; Sturchio, N. C.; Sun, Y. R.; Mueller, P.

2011-03-01

Atom trap trace analysis, a laser-based atom counting method, has been applied to analyze atmospheric Ar39 (half-life=269yr), a cosmogenic isotope with an isotopic abundance of 8×10-16. In addition to the superior selectivity demonstrated in this work, the counting rate and efficiency of atom trap trace analysis have been improved by 2 orders of magnitude over prior results. The significant applications of this new analytical capability lie in radioisotope dating of ice and water samples and in the development of dark matter detectors.

Selenium and Trace Element Distribution in Astragalus Plants: Developing a Differential Pulse Polarographic Method for Their Determination

OpenAIRE

SOMER, Güler; ÇALIŞKAN, A. Cengiz

2007-01-01

Astragalus plants have a wide range of applications in pharmaceuticals (gum tragacanth), as thickening agents in foods, and may have applications in controlling cancer cells. They are used as feed for animals and they are indicator plants for selenium. Because of their use in health-related areas it is very important to determine their selenium and trace element content with high accuracy. A new differential pulse polarographic method was established for trace element determination (...

A review of methods for assessment of trace element bioavailability in humans

International Nuclear Information System (INIS)

Ahmad, T.; Bilal, R.

2001-01-01

Deficiency of micronutrients is widespread among the low socio-economic strata of population. Different intervention strategies are used to eradicate these deficiencies. The most important step in the confirmation of the efficacy/success of an intervention is bioavailability. There are a number of methods for determining the bioavailability, involving both nuclear and non-nuclear techniques. Traditionally, bioavailability of different micronutrients was determined using the chemical balance method, that is, amount excreted subtracted from the amount ingested. Nowadays, methodologies have been developed for measuring the bioavailability of different trace elements incorporating the use of isotopes. The isotopic techniques are very accurate and highly specific. This paper summarizes the various methodologies available with special emphasis on nuclear methods. (author)

An assessment of diagnostic efficiency by Taguchi/DEA methods.

Science.gov (United States)

Taner, Mehmet Tolga; Sezen, Bulent

2009-01-01

The aim of this paper is to propose a new, objective and consistent method for the calculation of the diagnostic efficiency in medical applications. In this study, a hybrid method of Taguchi and DEA is proposed. This method reflects the diversity of inputs and outputs by incorporating the stepwise application of sensitivity, specificity, leveling threshold, and efficiency score. A hypothetical case study is given which involves eight readers of X-ray films in clinical radiology. The selected pairs of sensitivity and specificity yielded two efficient readers. After super efficiency analysis, Reader 6 is found to be the most efficient reader. The paper presents a new, objective and consistent method for the calculation of the diagnostic efficiency in medical applications.

Energy-efficient cooking methods

Energy Technology Data Exchange (ETDEWEB)

De, Dilip K. [Department of Physics, University of Jos, P.M.B. 2084, Jos, Plateau State (Nigeria); Muwa Shawhatsu, N. [Department of Physics, Federal University of Technology, Yola, P.M.B. 2076, Yola, Adamawa State (Nigeria); De, N.N. [Department of Mechanical and Aerospace Engineering, The University of Texas at Arlington, Arlington, TX 76019 (United States); Ikechukwu Ajaeroh, M. [Department of Physics, University of Abuja, Abuja (Nigeria)

2013-02-15

Energy-efficient new cooking techniques have been developed in this research. Using a stove with 649{+-}20 W of power, the minimum heat, specific heat of transformation, and on-stove time required to completely cook 1 kg of dry beans (with water and other ingredients) and 1 kg of raw potato are found to be: 710 {+-}kJ, 613 {+-}kJ, and 1,144{+-}10 s, respectively, for beans and 287{+-}12 kJ, 200{+-}9 kJ, and 466{+-}10 s for Irish potato. Extensive researches show that these figures are, to date, the lowest amount of heat ever used to cook beans and potato and less than half the energy used in conventional cooking with a pressure cooker. The efficiency of the stove was estimated to be 52.5{+-}2 %. Discussion is made to further improve the efficiency in cooking with normal stove and solar cooker and to save food nutrients further. Our method of cooking when applied globally is expected to contribute to the clean development management (CDM) potential. The approximate values of the minimum and maximum CDM potentials are estimated to be 7.5 x 10{sup 11} and 2.2 x 10{sup 13} kg of carbon credit annually. The precise estimation CDM potential of our cooking method will be reported later.

Spectrographic determination of traces of halogens; Dosage de traces d'halogenes par la methode spectrographique

Energy Technology Data Exchange (ETDEWEB)

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

1961-07-01

Hollow cathode source is employed for determining traces of halogens (fluorine - chlorine) in the uranium oxide U{sub 3}O{sub 8} qualitatively, detection of at least 40 ppm of fluorine, as alkali fluoride and 125 ppm of chlorine, is possible. (author) [French] Un tube a decharge a cathode creuse a ete utilise pour la determination spectrographique des halogenes (fluor - chlore) presentes a l'etat de traces dans un oxyde d'uranium U{sub 3}O{sub 8}. On a pu deceler qualitativement des teneurs de 40 ppm de fluor sous forme de fluorures alcalins. En ce qui concerne le chlore, la plus faible teneur decelee a ete de 125 ppm. (auteur)

Trace analysis of semiconductor materials

CERN Document Server

Cali, J Paul; Gordon, L

1964-01-01

Trace Analysis of Semiconductor Materials is a guidebook concerned with procedures of ultra-trace analysis. This book discusses six distinct techniques of trace analysis. These techniques are the most common and can be applied to various problems compared to other methods. Each of the four chapters basically includes an introduction to the principles and general statements. The theoretical basis for the technique involved is then briefly discussed. Practical applications of the techniques and the different instrumentations are explained. Then, the applications to trace analysis as pertaining

Variation in levels and removal efficiency of heavy and trace metals ...

African Journals Online (AJOL)

CPUT

trace metals from wastewater treatment plant effluents in Cape Town and .... Geographical locations and design .... The new. Bellville plant uses University of Cape Town design (UCT) ...... batteries, paints, fungicides, textiles, cosmetics, pulp,.

Trace analysis of actinides in the environment using resonance ionization mass spectrometry

International Nuclear Information System (INIS)

Raeder, Sebastian

2011-01-01

In this work the resonant ionization of neutral atoms using laser radiation was applied and optimized for ultra-trace analysis of the actinides thorium, uranium, neptunium and plutonium. The sensitive detection of these actinides is a challange for the monitoring and quantification of radioactive releases from nuclear facilities. Using resonance ionization spectroscopy combined with a newly developed quadrupole-mass-spectrometer, numerous energy levels in the atomic structure of these actinides could be identified. With this knowledge efficient excitation schemes for the mentioned actinides could be identified and characterised. The applied in-source-ionization ensures for a high detection efficiency due to the good overlap of laser radiation with the atomic beam and allows therefore for a low sample consumption which is required for the analysis of radio nuclides. The selective excitation processes in the resonant ionization method supresses unwanted contaminations and was optimized for analytical detection of ultra-trace amounts in environmental samples as well as for determination of isotopic compositions. The efficient in-source-ionization combined with high power pulsed laser radiation allows for detections efficiency up to 1%. For plutonium detection limits in the range of 10 4 -10 5 atoms could be demonstrated for synthetic samples as well as for first environmental samples. The usage of narrow bandwidth continuous wave lasers in combination with a transversal overlap of the laser radiation and the free propagating atomic beam enable for resolving individual isotopic shifts of the resonant transitions. This results in a high selectivity against dominant neighboring isotopes but with a significant loss in detection efficiency. For the ultra-trace isotope 236 U a detection limit down to 10 -9 for the isotope ratio N ( 236 U)/N ( 238 U) could be determined.

Application of neutron activation analysis to the development of a monitoring system for trace metals in coastal waters

International Nuclear Information System (INIS)

Karbe, L.; Schnier, C.

1976-03-01

In view of the development of monitoring systems for trace metals in coastal waters, a research program has been started for a better understanding of interrelationships between input of trace metals, water chemistry, suspended matter, sediment and organisms. For multielement determinations neutron activation analysis has been chosen. Since environmental studies require the analysis of a large number of samples, the efficiency of the method is improved by automation of the acquisition and analysis of the γ-spectra from the Ge(Li) detectors. An automatic sample changer with counting device is described. First applications of the method in environmental research are presented. (orig.) [de

Geometry-invariant GRIN lens: finite ray tracing.

Science.gov (United States)

Bahrami, Mehdi; Goncharov, Alexander V

2014-11-17

The refractive index distribution of the geometry-invariant gradient refractive index lens (GIGL) model is derived as a function of Cartesian coordinates. The adjustable external geometry of the GIGL model aims to mimic the shape of the human and animal crystalline lens. The refractive index distribution is based on an adjustable power-law profile, which provides additional flexibility of the model. An analytical method for layer-by-layer finite ray tracing through the GIGL model is developed and used to calculate aberrations of the GIGL model. The result of the finite ray tracing aberrations of the GIGL model are compared to those obtained with paraxial ray tracing. The derived analytical expression for the refractive index distribution can be employed in the reconstruction processes of the eye using the conventional ray tracing methods. The layer-by-layer finite ray tracing approach would be an asset in ray tracing through a modified GIGL model, where the refractive index distribution cannot be described analytically. Using the layer-by-layer finite ray-tracing method, the potential of the GIGL model in representing continuous as well as shell-like layered structures is illustrated and the results for both cases are presented and analysed.

Sectional localization of a small hepatocellular carcinoma in the right hepatic lobe by computed tomography: Comparison between the conventional and portal vein tracing methods

Energy Technology Data Exchange (ETDEWEB)

Zhou, Chun-Gao [Seoul National University Hospital, Department of Radiology, Jongro-gu, Seoul (Korea, Republic of); The First Affiliated Hospital of Nanjing Medical University, Department of Interventional Radiology, Nanjing (China); Chung, Jin Wook; Hur, Saebeom; Lee, Myungsu; Kim, Hyo-Cheol; Jae, Hwan Jun; Yin, Yong-Hu; Kim, Young Il [Seoul National University Hospital, Department of Radiology, Jongro-gu, Seoul (Korea, Republic of); Ahn, Sang-bu [Dongnam Institution of Radiological and Medical Sciences, Department of Radiology, Busan (Korea, Republic of); Cho, Baik Hwan [Chonbuk National University Hospital, Department of Radiology, Jeonju (Korea, Republic of)

2016-12-15

To compare the accuracy of the conventional and portal vein tracing methods in the right hepatic lobe in multidetector computed tomography (MDCT). This retrospective study included patients with hepatocellular carcinoma (HCC) lesions in the right hepatic lobe who underwent multiphasic MDCT and C-arm CT hepatic arteriography (C-arm CTHA) for chemoembolization. The accuracies of the conventional and portal vein tracing methods were evaluated using C-arm CTHA as the gold standard. A total of 147 patients with 205 HCC nodules were included. The C-arm CTHA could identify all the tumour-feeding arteries and consequently demonstrated that 120 lesions were located in the anterior section, 78 in the posterior section, and 7 in the border zone. The accuracy rates of conventional vs. portal vein tracing methods were 71.7 % vs. 98.3 % for the anterior section lesions, 67.9 % vs. 96.2 % for the posterior section, and 28.6 % vs. 57.1 % for the border zone. The portal vein tracing method was more accurate than the conventional method (P<0.001). The portal vein tracing method should be used for sectional localization of HCCs in the right lobe, because it predicts the location more accurately than the conventional method. (orig.)

A Rotor Tip Vortex Tracing Algorithm for Image Post-Processing

Science.gov (United States)

Overmeyer, Austin D.

2015-01-01

A neurite tracing algorithm, originally developed for medical image processing, was used to trace the location of the rotor tip vortex in density gradient flow visualization images. The tracing algorithm was applied to several representative test images to form case studies. The accuracy of the tracing algorithm was compared to two current methods including a manual point and click method and a cross-correlation template method. It is shown that the neurite tracing algorithm can reduce the post-processing time to trace the vortex by a factor of 10 to 15 without compromising the accuracy of the tip vortex location compared to other methods presented in literature.

The method innovation in nuclear equipment quality witness tracing and management

International Nuclear Information System (INIS)

Hao Guang

2012-01-01

The total construction cost of a nuclear power plant, equipment procurement cost accounts for about 47%-53%. Whether the quality of equipment can meet the technical requirements plays a significant role in the operation and maintenance of a nuclear power plant. Only if we adopt effective management can the equipment quality be ensured. As the most important method of quality control, the effective attendance and track of quality witness points has a crucial effect on contract smooth implementation as well. The essay mainly illustrates the method of quality witness point tracing and management and how to incorporate serious minded ideas and all take part in ways into quality management, hoping to offer some enlightenment on the innovation of nuclear power equipment quality management. (author)

Present and Future Challenges in Trace and Ultra-Trace Analysis

International Nuclear Information System (INIS)

Toulhoat, P.

2005-01-01

The analysis of trace and ultra-trace elements is continuously stimulating the progress in analytical chemistry. Environmental chemistry, radiochemistry, biology, health, agri-food are prescribers of trace analyses, with continuously increasing exigencies: lowering detection limits, lowering costs and analysis time, improving the quality of analytical information. Precise data about the chemical identity and chemical environment of analytes are now requested. Such pieces of information, beyond simple numerical data and confidence intervals, are necessary to understand studied systems, and to predict their evolution. From environmental contamination cases, one can envisage the various aspects of a problem, with for each of them its own exigencies and specificities in terms of analytical methods and approaches. The detection of traces and ultra-traces of actinides and fission products has been recently revisited and stimulates new technological developments (non proliferation issues, waste management). Data on their speciation in geological and biological media are essential for evaluating the safety of nuclear waste repositories. Various techniques are now used to determine speciation in liquid samples or on surfaces, with tremendous spatial resolutions or sensitivities. A new revolution in analytical chemistry is expected with the development of micro- or nano-analytical technologies. (author)

Discrete curved ray-tracing method for radiative transfer in an absorbing-emitting semitransparent slab with variable spatial refractive index

International Nuclear Information System (INIS)

Liu, L.H.

2004-01-01

A discrete curved ray-tracing method is developed to analyze the radiative transfer in one-dimensional absorbing-emitting semitransparent slab with variable spatial refractive index. The curved ray trajectory is locally treated as straight line and the complicated and time-consuming computation of ray trajectory is cut down. A problem of radiative equilibrium with linear variable spatial refractive index is taken as an example to examine the accuracy of the proposed method. The temperature distributions are determined by the proposed method and compared with the data in references, which are obtained by other different methods. The results show that the discrete curved ray-tracing method has a good accuracy in solving the radiative transfer in one-dimensional semitransparent slab with variable spatial refractive index

Determination of trace aluminum by fluorescence quenching method based on catalysis of potassium chlorate oxidizing alizarin red

Science.gov (United States)

Shao-Qin, Lin; Xuan, Lin; Shi-Rong, Hu; Li-Qing, Zeng; Yan, Wang; Li, Chen; Jia-Ming, Liu; Long-Di, Li

2005-11-01

A new method for the determination of trace aluminum has been proposed. It is based on the fact that alizarin red can emit strong and stable fluorescence at 80 °C for 30 min and Al 3+ can effectively catalyze potassium chlorate oxidizing alizarin red to form non-fluorescence complex which cause the fluorescence quenching. The linear dynamic range of this method is 0.040-4.00 ng l -1 with a detection limit of 5.3 pg l -1. The regression equation can be expressed as Δ If = 8.731 + 21.73 c (ng l -1), with the correlation coefficient r = 0.9992 ( n = 6). This sensitive, rapid and accurate method has been applied to the determination of trace aluminum(III) in human hair and tea samples successfully. What is more, the mechanism of catalyzing potassium chlorate oxidizing alizarin red by the fluorescence quenching method is also discussed.

Removal of trace organic chemical contaminants by a membrane bioreactor.

Science.gov (United States)

Trinh, T; van den Akker, B; Stuetz, R M; Coleman, H M; Le-Clech, P; Khan, S J

2012-01-01

Emerging wastewater treatment processes such as membrane bioreactors (MBRs) have attracted a significant amount of interest internationally due to their ability to produce high quality effluent suitable for water recycling. It is therefore important that their efficiency in removing hazardous trace organic contaminants be assessed. Accordingly, this study investigated the removal of trace organic chemical contaminants through a full-scale, package MBR in New South Wales, Australia. This study was unique in the context of MBR research because it characterised the removal of 48 trace organic chemical contaminants, which included steroidal hormones, xenoestrogens, pesticides, caffeine, pharmaceuticals and personal care products (PPCPs). Results showed that the removal of most trace organic chemical contaminants through the MBR was high (above 90%). However, amitriptyline, carbamazepine, diazepam, diclofenac, fluoxetine, gemfibrozil, omeprazole, sulphamethoxazole and trimethoprim were only partially removed through the MBR with the removal efficiencies of 24-68%. These are potential indicators for assessing MBR performance as these chemicals are usually sensitive to changes in the treatment systems. The trace organic chemical contaminants detected in the MBR permeate were 1 to 6 orders of magnitude lower than guideline values reported in the Australian Guidelines for Water Recycling. The outcomes of this study enhanced our understanding of the levels and removal of trace organic contaminants by MBRs.

The Alba ray tracing code: ART

Science.gov (United States)

Nicolas, Josep; Barla, Alessandro; Juanhuix, Jordi

2013-09-01

The Alba ray tracing code (ART) is a suite of Matlab functions and tools for the ray tracing simulation of x-ray beamlines. The code is structured in different layers, which allow its usage as part of optimization routines as well as an easy control from a graphical user interface. Additional tools for slope error handling and for grating efficiency calculations are also included. Generic characteristics of ART include the accumulation of rays to improve statistics without memory limitations, and still providing normalized values of flux and resolution in physically meaningful units.

Application of trace element analysis to determine trace element concentrations in the field of medicine. [Neutrons

Energy Technology Data Exchange (ETDEWEB)

Kasperek, K; Feinendegen, L E

1976-01-01

Applied trace elements research in medicine requires a sensitive and efficient technique of trace elements analysis, such as neutron activation analysis. Essential trace elements act as stabilizators (iron in haem), structural elements (silicon in fibrous tissue), in hormones (iodine in thyroid hormone), in vitamins (cobalt in vitamin B 12), and in enzymes. Most of the essential trace elements act as coenzymes or in coenzymes or directly as metabolic catalyzers. For example, selenium deficiency in PKU and maple syrup patients receiving dietary treatment can be detected by determining the selenium content of the serum, while low selenium values in the whole blood indicate liver cirrhosis. Acrodermatitis enteropathica can be diagnosed by determinig zinc in the serum, and pancreatic insufficiency by determining zinc in the pancreatic juice. Zinc also plays a part in disturbances of growth, in the healing of wounds, and in the insulin metabolism. Cobalt is important in some types of anaemia and in myocardiopathies. Trace elements are also necessary in the treatment of diseases, e.g. iron cobalt in some types of anaemia, and zinc in the delayed healing of wounds in the postoperative phase and in acrodermatitis enteropathica. Chromium is now being tested for the treatment of diabetes mellitus, and fluorides may be of interest in the treatment of osteoporosis. Finally, trace elements are important in the aetiology of acute poisoning, in nutrition, and in environmental protection.

Computational efficiency for the surface renewal method

Science.gov (United States)

Kelley, Jason; Higgins, Chad

2018-04-01

Measuring surface fluxes using the surface renewal (SR) method requires programmatic algorithms for tabulation, algebraic calculation, and data quality control. A number of different methods have been published describing automated calibration of SR parameters. Because the SR method utilizes high-frequency (10 Hz+) measurements, some steps in the flux calculation are computationally expensive, especially when automating SR to perform many iterations of these calculations. Several new algorithms were written that perform the required calculations more efficiently and rapidly, and that tested for sensitivity to length of flux averaging period, ability to measure over a large range of lag timescales, and overall computational efficiency. These algorithms utilize signal processing techniques and algebraic simplifications that demonstrate simple modifications that dramatically improve computational efficiency. The results here complement efforts by other authors to standardize a robust and accurate computational SR method. Increased speed of computation time grants flexibility to implementing the SR method, opening new avenues for SR to be used in research, for applied monitoring, and in novel field deployments.

Application of trace element analysis to determine trace element concentrations in the field of medicine

International Nuclear Information System (INIS)

Kasperek, K.; Feinendegen, L.E.

1976-01-01

Applied trace elements research in medicine requires a sensitive and efficient technique of trace elements analysis such as, e.g., neutron activation analysis. Essential trace elements act as stabilisators (iron in haem), structural elements (silicium in fibrous tissue), in hormones (iodine in thyroid hormone), in vitamins (cobalt in vitamin B 12), and in enzymes. Most of the essential trace elements act as coenzymes or in coenzymes or directly as metabolic catalysators. For example, selenium deficiency in PKU and maple syrup patients receiving dietary treatment can be detected by determining the selenium content of the serum, while low selenium values in the whole blood indicate liver cirrhosis. Acrodermatitis enteropathica can be diagnosed by determinig zinc in the serum, and pancreatic insufficiency by determining zinc in the pancreatic juice. Zinc also plays a part in disturbances of growth, in the healing of wounds, and in the insulin metabolism. Cobalt is important in some types of anaemia and in myocardiopathies. Trace elements are also necessary in the treatment of diseases, e.g. iron cobalt in some types of anaemia, and zinc in the delayed healing of wounds in the postoperative phase and in acrodermatitis enteropathica. Chromium is now being tested for the treatment of diabetes mellitus, and fluorides may be of interest in the treatment of osteoporosis. Finally, trace elements are important in the aetiology of acute poisoning, in nutrition, and in environmental protection. (orig./AK) [de

Methodology for processing pressure traces used as inputs for combustion analyses in diesel engines

International Nuclear Information System (INIS)

Rašić, Davor; Vihar, Rok; Baškovič, Urban Žvar; Katrašnik, Tomaž

2017-01-01

proposed • The efficiency of the new method was demonstrated by spectral analyses and calculations of rate-of-heat-release traces (paper)

A new method for determination of trace amount thorium-spectrophotometric determination of thorium in aqueous phase by chlorophosphonazo-mA

International Nuclear Information System (INIS)

Xia Yuanxian; Qian Hesheng

1986-01-01

In this paper the spectrophotometric method for determination of trace amount of thorium in weak acidic medium by chlorophosphonazo-mA is described. The composition of the complex was estimated to be 1:4 by slope ratio method. The apparent molar absorption of thorium at 675 nm is 9.2 x 10 4 . Beer's law is obeyed for 0-12.0 μg of thorium in 10 ml solution. The coefficient of variation for thorium is 0.88%. The method has been applied to the determination of trace amounts of thorium in the extraction process of thorium

Efficient numerical method for district heating system hydraulics

International Nuclear Information System (INIS)

Stevanovic, Vladimir D.; Prica, Sanja; Maslovaric, Blazenka; Zivkovic, Branislav; Nikodijevic, Srdjan

2007-01-01

An efficient method for numerical simulation and analyses of the steady state hydraulics of complex pipeline networks is presented. It is based on the loop model of the network and the method of square roots for solving the system of linear equations. The procedure is presented in the comprehensive mathematical form that could be straightforwardly programmed into a computer code. An application of the method to energy efficiency analyses of a real complex district heating system is demonstrated. The obtained results show a potential for electricity savings in pumps operation. It is shown that the method is considerably more effective than the standard Hardy Cross method still widely used in engineering practice. Because of the ease of implementation and high efficiency, the method presented in this paper is recommended for hydraulic steady state calculations of complex networks

Preconcentration and Speciation of Trace Elements and Trace-Element Analogues of Radionuclides by Neutron Activation Analysis

International Nuclear Information System (INIS)

Chatt, A.

1999-01-01

We have developed a number of preconcentration neutron activation analysis (PNAA) methods in our laboratory for the determination of trace elements in a variety of complex sample matrices. We developed a number of cocrystallization and coprecipitation methods for the determination of trace elements in water samples. We developed several methods for the determination of I in foods and diets. We have developed a number of PNAA methods in our laboratory We determined As and Sb in geological materials and natural waters by coprecipitation with Se and Au in silicate rocks and ores by coprecipitation with Te followed by NAA. We developed an indirect NAA method for the determination of B in leachates of borosilicate glass. We have been interested in studying the speciation of Am, Tc, and Np in simulated vitrified groundwater leachates of high-level wastes under oxid and anoxic conditions using a number of techniques. We then used PNAA methods to study speciation of trace-element analogues of radionuclides. We have been able to apply biochemical techniques and NAA for the separation, preconcentration, and characterization of metalloprotein and protein-bound trace-element species in subcellular fractions of bovine kidneys. Lately, we have concentrated our efforts to develop chemical and biochemical methods in conjunction with NAA, NMR, and MS for the separation and identification of extractable organohalogens (EOX) in tissues of beluga whales, cod, and northern pink shrimp

Fast voxel and polygon ray-tracing algorithms in intensity modulated radiation therapy treatment planning

International Nuclear Information System (INIS)

Fox, Christopher; Romeijn, H. Edwin; Dempsey, James F.

2006-01-01

We present work on combining three algorithms to improve ray-tracing efficiency in radiation therapy dose computation. The three algorithms include: An improved point-in-polygon algorithm, incremental voxel ray tracing algorithm, and stereographic projection of beamlets for voxel truncation. The point-in-polygon and incremental voxel ray-tracing algorithms have been used in computer graphics and nuclear medicine applications while the stereographic projection algorithm was developed by our group. These algorithms demonstrate significant improvements over the current standard algorithms in peer reviewed literature, i.e., the polygon and voxel ray-tracing algorithms of Siddon for voxel classification (point-in-polygon testing) and dose computation, respectively, and radius testing for voxel truncation. The presented polygon ray-tracing technique was tested on 10 intensity modulated radiation therapy (IMRT) treatment planning cases that required the classification of between 0.58 and 2.0 million voxels on a 2.5 mm isotropic dose grid into 1-4 targets and 5-14 structures represented as extruded polygons (a.k.a. Siddon prisms). Incremental voxel ray tracing and voxel truncation employing virtual stereographic projection was tested on the same IMRT treatment planning cases where voxel dose was required for 230-2400 beamlets using a finite-size pencil-beam algorithm. Between a 100 and 360 fold cpu time improvement over Siddon's method was observed for the polygon ray-tracing algorithm to perform classification of voxels for target and structure membership. Between a 2.6 and 3.1 fold reduction in cpu time over current algorithms was found for the implementation of incremental ray tracing. Additionally, voxel truncation via stereographic projection was observed to be 11-25 times faster than the radial-testing beamlet extent approach and was further improved 1.7-2.0 fold through point-classification using the method of translation over the cross product technique

Analytical method for the determination of trace levels of steroid hormones and corticosteroids in soil, based on PLE/SPE/LC-MS/MS.

Science.gov (United States)

Gineys, N; Giroud, B; Vulliet, E

2010-07-01

The aim of this study was to develop an efficient, sensitive and reliable analytical method for the determination of traces of steroid hormones (including oestrogen, androgens and progestagens) and corticosteroids in soil. A method of sample preparation involving pressurized liquid extraction (PLE) and solid-phase extraction (SPE) was developed for the determination of six steroids and five corticosteroids in soils, followed by analysis by liquid chromatography-tandem mass spectrometry. The conditions employed for PLE involved acetone/methanol (50:50) as the extracting solvent, a temperature of 80 degrees C, two cycles and a static time of 5 min. The extraction was followed by a SPE clean-up based on a polymeric phase. With use of protocol, a residual matrix effect was, however, highlighted. The limit of detection in soil was 0.08-0.89 ng/g for steroids and 0.09-2.84 ng/g for corticosteroids.

A multi-element solid-phase extraction method for trace metals determination in environmental samples on Amberlite XAD-2000

International Nuclear Information System (INIS)

Bulut, Volkan Numan; Gundogdu, Ali; Duran, Celal; Senturk, Hasan Basri; Soylak, Mustafa; Elci, Latif; Tufekci, Mehmet

2007-01-01

A method for the preconcentration of some transition elements at trace level was proposed using a column filled with Amberlite XAD-2000 resin. Metal ions were adsorbed on XAD-2000 as their diethyldithiocarbamate chelates, then analytes retained on the resin were eluted by 1 mol L -1 nitric acid in acetone and determined by flame atomic absorption spectrometry (FAAS). The influences of some analytical parameters including pH of sample solution, ligand amount, the type, concentration and volume of elution solution, flow rates of the sample and eluent solutions, adsorption capacity of the resin and sample volume on the preconcentration efficiency have been investigated. The influences of some matrix elements were also examined. The detection limit (N = 20, 3 sigma) for Mn(II), Fe(II), Co(II), Cu(II), Cd(II), Zn(II), Pb(II) and Ni(II) were found as 0.20, 0.35, 0.25, 0.20, 0.20, 0.15, 0.45 and 0.25 μg L -1 , respectively. The validation of the procedure was carried out by analysis of certified reference materials. The proposed method was applied to natural waters and kale vegetable (Brassica oleracea var. acephala)

A multi-element solid-phase extraction method for trace metals determination in environmental samples on Amberlite XAD-2000

Energy Technology Data Exchange (ETDEWEB)

Bulut, Volkan Numan [Department of Chemistry, Giresun Faculty of Arts and Sciences, Karadeniz Technical University, 28049 Giresun (Turkey); Gundogdu, Ali [Department of Chemistry, Faculty of Arts and Sciences, Karadeniz Technical University, 61080 Trabzon (Turkey); Duran, Celal [Department of Chemistry, Faculty of Arts and Sciences, Karadeniz Technical University, 61080 Trabzon (Turkey); Senturk, Hasan Basri [Department of Chemistry, Faculty of Arts and Sciences, Karadeniz Technical University, 61080 Trabzon (Turkey); Soylak, Mustafa [Department of Chemistry, Faculty of Arts and Sciences, Erciyes University, 38039 Kayseri (Turkey)]. E-mail: msoylak@gmail.com; Elci, Latif [Department of Chemistry, Faculty of Arts and Sciences, Pamukkale University, 20020 Denizli (Turkey); Tufekci, Mehmet [Department of Chemistry, Faculty of Arts and Sciences, Karadeniz Technical University, 61080 Trabzon (Turkey)

2007-07-19

A method for the preconcentration of some transition elements at trace level was proposed using a column filled with Amberlite XAD-2000 resin. Metal ions were adsorbed on XAD-2000 as their diethyldithiocarbamate chelates, then analytes retained on the resin were eluted by 1 mol L{sup -1} nitric acid in acetone and determined by flame atomic absorption spectrometry (FAAS). The influences of some analytical parameters including pH of sample solution, ligand amount, the type, concentration and volume of elution solution, flow rates of the sample and eluent solutions, adsorption capacity of the resin and sample volume on the preconcentration efficiency have been investigated. The influences of some matrix elements were also examined. The detection limit (N = 20, 3 sigma) for Mn(II), Fe(II), Co(II), Cu(II), Cd(II), Zn(II), Pb(II) and Ni(II) were found as 0.20, 0.35, 0.25, 0.20, 0.20, 0.15, 0.45 and 0.25 {mu}g L{sup -1}, respectively. The validation of the procedure was carried out by analysis of certified reference materials. The proposed method was applied to natural waters and kale vegetable (Brassica oleracea var. acephala)

Emissions of trace gases from Australian temperate forest fires: emission factors and dependence on modified combustion efficiency

Science.gov (United States)

Guérette, Elise-Andrée; Paton-Walsh, Clare; Desservettaz, Maximilien; Smith, Thomas E. L.; Volkova, Liubov; Weston, Christopher J.; Meyer, Carl P.

2018-03-01

We characterised trace gas emissions from Australian temperate forest fires through a mixture of open-path Fourier transform infrared (OP-FTIR) measurements and selective ion flow tube mass spectrometry (SIFT-MS) and White cell FTIR analysis of grab samples. We report emission factors for a total of 25 trace gas species measured in smoke from nine prescribed fires. We find significant dependence on modified combustion efficiency (MCE) for some species, although regional differences indicate that the use of MCE as a proxy may be limited. We also find that the fire-integrated MCE values derived from our in situ on-the-ground open-path measurements are not significantly different from those reported for airborne measurements of smoke from fires in the same ecosystem. We then compare our average emission factors to those measured for temperate forest fires elsewhere (North America) and for fires in another dominant Australian ecosystem (savanna) and find significant differences in both cases. Indeed, we find that although the emission factors of some species agree within 20 %, including those of hydrogen cyanide, ethene, methanol, formaldehyde and 1,3-butadiene, others, such as acetic acid, ethanol, monoterpenes, ammonia, acetonitrile and pyrrole, differ by a factor of 2 or more. This indicates that the use of ecosystem-specific emission factors is warranted for applications involving emissions from Australian forest fires.

Efficiency Test Method for Electric Vehicle Chargers

DEFF Research Database (Denmark)

Kieldsen, Andreas; Thingvad, Andreas; Martinenas, Sergejus

2016-01-01

This paper investigates different methods for measuring the charger efficiency of mass produced electric vehicles (EVs), in order to compare the different models. The consumers have low attention to the loss in the charger though the impact on the driving cost is high. It is not a high priority...... different vehicles. A unified method for testing the efficiency of the charger in EVs, without direct access to the component, is presented. The method is validated through extensive tests of the models Renault Zoe, Nissan LEAF and Peugeot iOn. The results show a loss between 15 % and 40 %, which is far...

A fast and efficient adaptive parallel ray tracing based model for thermally coupled surface radiation in casting and heat treatment processes

International Nuclear Information System (INIS)

Fainberg, J; Schaefer, W

2015-01-01

A new algorithm for heat exchange between thermally coupled diffusely radiating interfaces is presented, which can be applied for closed and half open transparent radiating cavities. Interfaces between opaque and transparent materials are automatically detected and subdivided into elementary radiation surfaces named tiles. Contrary to the classical view factor method, the fixed unit sphere area subdivision oriented along the normal tile direction is projected onto the surrounding radiation mesh and not vice versa. Then, the total incident radiating flux of the receiver is approximated as a direct sum of radiation intensities of representative “senders” with the same weight factor. A hierarchical scheme for the space angle subdivision is selected in order to minimize the total memory and the computational demands during thermal calculations. Direct visibility is tested by means of a voxel-based ray tracing method accelerated by means of the anisotropic Chebyshev distance method, which reuses the computational grid as a Chebyshev one. The ray tracing algorithm is fully parallelized using MPI and takes advantage of the balanced distribution of all available tiles among all CPU's. This approach allows tracing of each particular ray without any communication. The algorithm has been implemented in a commercial casting process simulation software. The accuracy and computational performance of the new radiation model for heat treatment, investment and ingot casting applications is illustrated using industrial examples. (paper)

Studies of trace elements in biological systems by energy dispersive x-ray fluorescence (EDXRF) and proton induced x-ray emission (PIXE) methods

International Nuclear Information System (INIS)

Lal, Madan; Choudhury, R.K.

1991-01-01

Applicability of EDXRF and PIXE techniques for trace elemental analysis in biology and medicine is demonstrated. Due to increasing importance of the need to determine the role of essential and toxic trace elements in human health and disease, the method of PIXE analysis has assumed great importance in recent years. This method has been found to be particularly useful for biological samples. EDXRF also offers a complimentary method particularly in the range of elements of Z=45 to 60 where the sensitivity of PIXE analysis is not quite adequate. EDXRF can also be usefully employed for other elements of the periodic chart with relatively lesser sensitivity. The work being presented here includes trace element analysis of normal and cancer bearing tissues of Swiss mice, trace element profiles in cancerous human oesophageal tissues, investigations on the effect of toxic metals such as Hg from Ayurvedic drugs on Wister rats, and investigations of blood lead levels of children admitted to Sion Hospital from Dharavi slums of Bombay. The results of these investigations are presented and discussed. (author). 21 refs., 8 figs., 3 tabs

Spoken word recognition without a TRACE

Science.gov (United States)

Hannagan, Thomas; Magnuson, James S.; Grainger, Jonathan

2013-01-01

How do we map the rapid input of spoken language onto phonological and lexical representations over time? Attempts at psychologically-tractable computational models of spoken word recognition tend either to ignore time or to transform the temporal input into a spatial representation. TRACE, a connectionist model with broad and deep coverage of speech perception and spoken word recognition phenomena, takes the latter approach, using exclusively time-specific units at every level of representation. TRACE reduplicates featural, phonemic, and lexical inputs at every time step in a large memory trace, with rich interconnections (excitatory forward and backward connections between levels and inhibitory links within levels). As the length of the memory trace is increased, or as the phoneme and lexical inventory of the model is increased to a realistic size, this reduplication of time- (temporal position) specific units leads to a dramatic proliferation of units and connections, begging the question of whether a more efficient approach is possible. Our starting point is the observation that models of visual object recognition—including visual word recognition—have grappled with the problem of spatial invariance, and arrived at solutions other than a fully-reduplicative strategy like that of TRACE. This inspires a new model of spoken word recognition that combines time-specific phoneme representations similar to those in TRACE with higher-level representations based on string kernels: temporally independent (time invariant) diphone and lexical units. This reduces the number of necessary units and connections by several orders of magnitude relative to TRACE. Critically, we compare the new model to TRACE on a set of key phenomena, demonstrating that the new model inherits much of the behavior of TRACE and that the drastic computational savings do not come at the cost of explanatory power. PMID:24058349

Efficient Training Methods for Conditional Random Fields

National Research Council Canada - National Science Library

Sutton, Charles A

2008-01-01

.... In this thesis, I investigate efficient training methods for conditional random fields with complex graphical structure, focusing on local methods which avoid propagating information globally along the graph...

Study of the extraction of the traces of Cadmium through the method of subestequiometric isotope dilution

International Nuclear Information System (INIS)

Garate V, Z.

1990-01-01

In this work, it has been used the method of subestequiometric isotope dilution for the determination of traces of cadmium and it has been compared with other conventional's methods for study its performance. The conditions of the experiment had been studied carefully in order to optimize the parameters such as pH, (8,0 - 10,1) it used the buffer NH 3 :NH 4 Cl, the time of agitation (>120 s) and the concentration of the organic reactive (dithizone). Besides, it obtains the respective curve of calibration. In this study, we can watch a line relation in all the range studied (5-40 μg of Cd). This method applied to the analysis of Cadmium in a certified sample of H-8 of the IAEA, it gives us the next value: 195 ± 5,4 ppm (LOD= 1,5 ppm, LOQ= 4,8 ppm), it is enough satisfactory in comparison with the certified middle value of 188,9±19 ppm. It demonstrates the utility of the method in the Cadmium traces analysis if it disposes of the radioisotope of this element and the appropriate detection equipment. (DEM). 34 refs., 15 tabs., 7 figs

Electric discharge for treatment of trace contaminants

Science.gov (United States)

Flamm, D. L.; Wydeven, T. J. (Inventor)

1978-01-01

A radio frequency glow discharge reactor is described for removing trace oxidizable contaminants from an oxygen bearing atmosphere. The reaction chamber is defined by an inner metal electrode facing a dielectric backed by an outer conductive electrode. In one embodiment, a conductive liquid forms the conductor of an outer electrode and cools the dielectric. A resonator coupled to a variable radio frequency source generates the high voltages for creating a glow discharge in the chamber at a predetermined pressure whereby the trace contaminants are oxidized into a few simple non-toxic products that may be easily recovered. The corresponding process for removal of trace contaminants from an oxygen-bearing atmosphere with high efficiency independent of the concentration level is also disclosed.

A novel in vitro method for detecting undifferentiated human pluripotent stem cells as impurities in cell therapy products using a highly efficient culture system.

Directory of Open Access Journals (Sweden)

Keiko Tano

Full Text Available Innovative applications of cell therapy products (CTPs derived from human pluripotent stem cells (hPSCs in regenerative medicine are currently being developed. The presence of residual undifferentiated hPSCs in CTPs is a quality concern associated with tumorigencity. However, no simple in vitro method for direct detection of undifferentiated hPSCs that contaminate CTPs has been developed. Here, we show a novel approach for direct and sensitive detection of a trace amount of undifferentiated human induced pluripotent stem cells (hiPSCs using a highly efficient amplification method in combination with laminin-521 and Essential 8 medium. Essential 8 medium better facilitated the growth of hiPSCs dissociated into single cells on laminin-521 than in mTeSR1 medium. hiPSCs cultured on laminin-521 in Essential 8 medium were maintained in an undifferentiated state and they maintained the ability to differentiate into various cell types. Essential 8 medium allowed robust hiPSC proliferation plated on laminin-521 at low cell density, whereas mTeSR1 did not enhance the cell growth. The highly efficient culture system using laminin-521 and Essential 8 medium detected hiPSCs spiked into primary human mesenchymal stem cells (hMSCs or human neurons at the ratio of 0.001%-0.01% as formed colonies. Moreover, this assay method was demonstrated to detect residual undifferentiated hiPSCs in cell preparations during the process of hMSC differentiation from hiPSCs. These results indicate that our highly efficient amplification system using a combination of laminin-521 and Essential 8 medium is able to detect a trace amount of undifferentiated hPSCs contained as impurities in CTPs and would contribute to quality assessment of hPSC-derived CTPs during the manufacturing process.

Approximate P-wave ray tracing and dynamic ray tracing in weakly orthorhombic media of varying symmetry orientation

KAUST Repository

Masmoudi, Nabil; Pšenčí k, Ivan

2014-01-01

We present an approximate, but efficient and sufficiently accurate P-wave ray tracing and dynamic ray tracing procedure for 3D inhomogeneous, weakly orthorhombic media with varying orientation of symmetry planes. In contrast to commonly used approaches, the orthorhombic symmetry is preserved at any point of the model. The model is described by six weak-anisotropy parameters and three Euler angles, which may vary arbitrarily, but smoothly, throughout the model. We use the procedure for the calculation of rays and corresponding two-point traveltimes in a VSP experiment in a part of the BP benchmark model generalized to orthorhombic symmetry.

Trace element emissions from coal

Energy Technology Data Exchange (ETDEWEB)

NONE

2012-09-15

Trace elements are emitted during coal combustion. The quantity, in general, depends on the physical and chemical properties of the element itself, the concentration of the element in the coal, the combustion conditions and the type of particulate control device used, and its collection efficiency as a function of particle size. Some trace elements become concentrated in certain particle streams following combustion such as bottom ash, fly ash, and flue gas particulate matter, while others do not. Various classification schemes have been developed to describe this partitioning behaviour. These classification schemes generally distinguish between: Class 1: elements that are approximately equally concentrated in the fly ash and bottom ash, or show little or no fine particle enrichment, examples include Mn, Be, Co and Cr; Class 2: elements that are enriched in the fly ash relative to bottom ash, or show increasing enrichment with decreasing particle size, examples include As, Cd, Pb and Sb; Class 3: elements which are emitted in the gas phase (primarily Hg (not discussed in this review), and in some cases, Se). Control of class 1 trace elements is directly related to control of total particulate matter emissions, while control of the class 2 elements depends on collection of fine particulates. Due to the variability in particulate control device efficiencies, emission rates of these elements can vary substantially. The volatility of class 3 elements means that particulate controls have only a limited impact on the emissions of these elements.

Significantly improving trace thallium removal from surface waters during coagulation enhanced by nanosized manganese dioxide.

Science.gov (United States)

Huangfu, Xiaoliu; Ma, Chengxue; Ma, Jun; He, Qiang; Yang, Chun; Jiang, Jin; Wang, Yaan; Wu, Zhengsong

2017-02-01

Thallium (Tl) is an element of high toxicity and significant accumulation in human body. There is an urgent need for the development of appropriate strategies for trace Tl removal in drinking water treatment plants. In this study, the efficiency and mechanism of trace Tl (0.5 μg/L) removal by conventional coagulation enhanced by nanosized manganese dioxide (nMnO 2 ) were explored in simulated water and two representative surface waters (a river water and a reservoir water obtained from Northeast China). Experimental results showed that nMnO 2 significantly improve Tl(I) removal from selected waters. The removal efficiency was dramatically higher in the simulated water, demonstrating by less than 0.1 μg/L Tl residual. The enhancement of trace Tl removal in the surface waters decreased to a certain extent. Both adjusting water pH to alkaline condition and preoxidation of Tl(I) to Tl(III) benefit trace Tl removal from surface waters. Data also indicated that competitive cation of Ca 2+ decreased the efficiency of trace Tl removal, resulting from the reduction of Tl adsorption on nMnO 2 . Humic acid could largely low Tl removal efficiency during nMnO 2 enhanced coagulation processes. Trace elemental Tl firstly adsorbed on nMnO 2 and then removed accompanying with nMnO 2 settling. The information obtained in the present study may provide a potential strategy for drinking water treatment plants threatened by trace Tl. Copyright © 2016 Elsevier Ltd. All rights reserved.

Comparison of three analytical methods for the determination of trace elements in whole blood

International Nuclear Information System (INIS)

Ward, N.I.; Stephens, R.; Ryan, D.E.

1979-01-01

Three different analytical techniques were compared in a study of the role of trace elements in multiple sclerosis. Data for eight elements (Cd, Co, Cr, Cu, Mg, Mn, Pb, Zn) from neutron activation, flame atomic absorption and electrothermal atomic absorption methods were compared and evaluated statistically. No difference (probability less than 0.001) was observed in the elemental values obtained. Comparison of data between suitably different analytical methods gives increased confidence in the results obtained and is of particular value when standard reference materials are not available. (Auth.)

Automated computer analysis of plasma-streak traces from SCYLLAC

International Nuclear Information System (INIS)

Whitman, R.L.; Jahoda, F.C.; Kruger, R.P.

1977-01-01

An automated computer analysis technique that locates and references the approximate centroid of single- or dual-streak traces from the Los Alamos Scientific Laboratory SCYLLAC facility is described. The technique also determines the plasma-trace width over a limited self-adjusting region. The plasma traces are recorded with streak cameras on Polaroid film, then scanned and digitized for processing. The analysis technique uses scene segmentation to separate the plasma trace from a reference fiducial trace. The technique employs two methods of peak detection; one for the plasma trace and one for the fiducial trace. The width is obtained using an edge-detection, or slope, method. Timing data are derived from the intensity modulation of the fiducial trace. To smooth (despike) the output graphs showing the plasma-trace centroid and width, a technique of ''twicing'' developed by Tukey was employed. In addition, an interactive sorting algorithm allows retrieval of the centroid, width, and fiducial data from any test shot plasma for post analysis. As yet, only a limited set of sixteen plasma traces has been processed using this technique

Automated computer analysis of plasma-streak traces from SCYLLAC

International Nuclear Information System (INIS)

Whiteman, R.L.; Jahoda, F.C.; Kruger, R.P.

1977-11-01

An automated computer analysis technique that locates and references the approximate centroid of single- or dual-streak traces from the Los Alamos Scientific Laboratory SCYLLAC facility is described. The technique also determines the plasma-trace width over a limited self-adjusting region. The plasma traces are recorded with streak cameras on Polaroid film, then scanned and digitized for processing. The analysis technique uses scene segmentation to separate the plasma trace from a reference fiducial trace. The technique employs two methods of peak detection; one for the plasma trace and one for the fiducial trace. The width is obtained using an edge-detection, or slope, method. Timing data are derived from the intensity modulation of the fiducial trace. To smooth (despike) the output graphs showing the plasma-trace centroid and width, a technique of ''twicing'' developed by Tukey was employed. In addition, an interactive sorting algorithm allows retrieval of the centroid, width, and fiducial data from any test shot plasma for post analysis. As yet, only a limited set of the plasma traces has been processed with this technique

Evaluation of simulation alternatives for the brute-force ray-tracing approach used in backlight design

Science.gov (United States)

Desnijder, Karel; Hanselaer, Peter; Meuret, Youri

2016-04-01

A key requirement to obtain a uniform luminance for a side-lit LED backlight is the optimised spatial pattern of structures on the light guide that extract the light. The generation of such a scatter pattern is usually performed by applying an iterative approach. In each iteration, the luminance distribution of the backlight with a particular scatter pattern is analysed. This is typically performed with a brute-force ray-tracing algorithm, although this approach results in a time-consuming optimisation process. In this study, the Adding-Doubling method is explored as an alternative way for evaluating the luminance of a backlight. Due to the similarities between light propagating in a backlight with extraction structures and light scattering in a cloud of light scatterers, the Adding-Doubling method which is used to model the latter could also be used to model the light distribution in a backlight. The backlight problem is translated to a form upon which the Adding-Doubling method is directly applicable. The calculated luminance for a simple uniform extraction pattern with the Adding-Doubling method matches the luminance generated by a commercial raytracer very well. Although successful, no clear computational advantage over ray tracers is realised. However, the dynamics of light propagation in a light guide as used the Adding-Doubling method, also allow to enhance the efficiency of brute-force ray-tracing algorithms. The performance of this enhanced ray-tracing approach for the simulation of backlights is also evaluated against a typical brute-force ray-tracing approach.

Intraoral gothic arch tracing.

Science.gov (United States)

Rubel, Barry; Hill, Edward E

2011-01-01

In order to create optimum esthetics, function and phonetics in complete denture fabrication, it is necessary to record accurate maxillo-mandibular determinants of occlusion. This requires clinical skill to establish an accurate, verifiable and reproducible vertical dimension of occlusion (VDO) and centric relation (CR). Correct vertical relation depends upon a consideration of several factors, including muscle tone, inter-dental arch space and parallelism of the ridges. Any errors made while taking maxillo-mandibular jaw relation records will result in dentures that are uncomfortable and, possibly, unwearable. The application of a tracing mechanism such as the Gothic arch tracer (a central bearing device) is a demonstrable method of determining centric relation. Intraoral Gothic arch tracers provide the advantage of capturing VDO and CR in an easy-to-use technique for practitioners. Intraoral tracing (Gothic arch tracing) is a preferred method of obtaining consistent positions of the mandible in motion (retrusive, protrusive and lateral) at a comfortable VDO.

Enhanced gene ranking approaches using modified trace ratio algorithm for gene expression data

Directory of Open Access Journals (Sweden)

Shruti Mishra

Full Text Available Microarray technology enables the understanding and investigation of gene expression levels by analyzing high dimensional datasets that contain few samples. Over time, microarray expression data have been collected for studying the underlying biological mechanisms of disease. One such application for understanding the mechanism is by constructing a gene regulatory network (GRN. One of the foremost key criteria for GRN discovery is gene selection. Choosing a generous set of genes for the structure of the network is highly desirable. For this role, two suitable methods were proposed for selection of appropriate genes. The first approach comprises a gene selection method called Information gain, where the dataset is reformed and fused with another distinct algorithm called Trace Ratio (TR. Our second method is the implementation of our projected modified TR algorithm, where the scoring base for finding weight matrices has been re-designed. Both the methods' efficiency was shown with different classifiers that include variants of the Artificial Neural Network classifier, such as Resilient Propagation, Quick Propagation, Back Propagation, Manhattan Propagation and Radial Basis Function Neural Network and also the Support Vector Machine (SVM classifier. In the study, it was confirmed that both of the proposed methods worked well and offered high accuracy with a lesser number of iterations as compared to the original Trace Ratio algorithm. Keywords: Gene regulatory network, Gene selection, Information gain, Trace ratio, Canonical correlation analysis, Classification

Validation of a field filtration technique for characterization of suspended particulate matter from freshwater. Part II. Minor, trace and ultra trace elements

International Nuclear Information System (INIS)

Odman, Fredrik; Ruth, Thomas; Rodushkin, Ilia; Ponter, Christer

2006-01-01

A field filtration method for the concentration and separation of suspended particulate matter (SPM) from freshwater systems and the subsequent determination of minor, trace and ultra trace elements (As, Ba, Be, Cd, Co, Cr, Cs, Cu, Ga, Hf, Mo, Nb, Ni, Pb, Rb, Sb, Sc, Sn, Sr, Ta, Th, Tl, U, V, W, Zn and Zr) is validated with respect to detection limits, precision and bias. The validation comprises the whole procedure including filtration, sample digestion and instrumental analysis. The method includes two digestion procedures (microwave acid digestion and alkali fusion) in combination with inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma quadrupole mass spectrometry (ICP-QMS). Total concentrations of these 27 trace and minor elements have been determined in suspended particulate matter (SPM) from lake and river water with low levels of suspended solids ( -1 DW), and a wide range of element concentrations. The precision of the method including filtration, digestion and instrumental determination ranges between 8% and 18% RSD for most elements on a dry weight basis. Higher recovery after acid digestion is found for some elements, probably because of volatilization or retention losses in the fusion procedure. Other elements show higher recovery after fusion, which is explained by more efficient decomposition of refractory mineral phases relative to the non-total acid digestion. Non-detectable concentrations of some elements are reported due to small differences between blank filter levels and the amounts of elements present on the filters after sampling. The method limits of detection range between 0.7 ng and 2.65 μg, as estimated from the blank filter samples. These detection limits are 10-550 times higher compared to the corresponding instrumental limits of detection. The accuracy and bias of the overall analytical procedure was assessed from replicate analysis of certified reference materials. A critical evaluation of

An ICP-AES method for the determination of trace metals in uranium by solvent extraction using KSM-17

International Nuclear Information System (INIS)

Jacob, Mary; Radhakrishnan, K.; Dhami, P.S.; Kulkarni, V.T.; Joshi, M.V.; Patwardhan, A.B.; Ramanujam, A.; Mathur, J.N.

1994-01-01

This paper describes the studies carried out for the determination of trace metallic impurities in uranium solutions. Uranium matrix is separated from the impurity elements by its selective extraction using 2-ethylhexyl hydrogen 2-ethylhexyl phosphonate (KSM-17, equivalent to PC88A). The aqueous phase is analysed for trace impurities by inductively coupled argon plasma atomic emission spectrometry. The studies also include recovery of impurities at various acidities and spectral interferences of uranium over the analyte element channels. Based on the above studies, a method has been standardised for the analysis of nineteen elements in uranium solutions. The relative standard deviation of the method for various elements is in the range of +- 1-5%. (author). 7 refs., 8 tabs., 1 fig

Can liming change root anatomy, biomass allocation and trace element distribution among plant parts of Salix × smithiana in trace element-polluted soils?

Science.gov (United States)

Vondráčková, Stanislava; Tlustoš, Pavel; Száková, Jiřina

2017-08-01

Willows (Salix spp.) are considered to be effective for the phytoremediation of trace elements from contaminated soils, but their efficiency is limited in heavily polluted soils because of poor growth. Liming can be a desirable measure to decrease the plant availability of elements, resulting in improved plant development. Notably, large root area and maximum soil penetration are basic parameters that improve the efficiency of phytoremediation. The impact of soil chemical properties on willow root anatomy and the distribution of trace elements below-ground have rarely been studied. The effect of liming on root parameters, biomass allocation and trace element distribution in non-harvestable (coarse roots, fine roots, stumps) and harvestable plant parts (twigs and leaves) of Salix × smithiana was assessed at the end of a 4-year pot experiment with two trace element-polluted soils that differed in terms of soil pH. Stump biomass predominated in weakly acidic soil. In neutral soil, the majority of biomass was located in fine roots and stumps; the difference from other plant parts was minor. Trace elements were the most concentrated in fine roots. Translocation to above-ground biomass increased as follows: Pb roots roots). Lime application decreased the concentrations of mobile Cd and Zn and related levels in plants, improved biomass production and root parameters and increased the removal of all trace elements in weakly acidic soil. None or minimum differences in the monitored parameters were recorded for dolomite treatments in both soils. The dose and source of liming had crucial effects on root anatomy. Growing willows in limed trace element-polluted soils is a suitable measure for combination of two remediation strategies, i.e. phytoextraction of Cd and Zn and assisted phytostabilization of As and Pb.

Nuclear analytical methods for trace element studies in calcified tissues

International Nuclear Information System (INIS)

Chaudhry, M.A.; Chaudhry, M.N.

2001-01-01

Full text: Various nuclear analytical methods have been developed and applied to determine the elemental composition of calcified tissues (teeth and bones). Fluorine was determined by prompt gamma activation analysis through the 19 F(p,ag) 16 O reaction. Carbon was measured by activation analysis with He-3 ions, and the technique of Proton-Induced X-ray Emission (PIXE) was applied to simultaneously determine Ca, P, and trace elements in well-documented teeth. Dental hard tissues, enamel, dentine, cement, and their junctions, as well as different parts of the same tissue, were examined separately. Furthermore, using a Proton Microprobe, we measured the surface distribution of F and other elements on and around carious lesions on the enamel. The depth profiles of F, and other elements, were also measured right up to the amelodentin junction

Requirement-specific use of trace element biogas additives under consideration of the bioavailability; Bedarfsgerechter Einsatz von Spurenelement-Biogasadditiven unter Beruecksichtigung der Bioverfuegbarkeit

Energy Technology Data Exchange (ETDEWEB)

Feher, Adam; Fritz, Thomas; Loewen, Achim; Nelles, Michael [HAWK Hochschule fuer Angewandte Wissenschaft und Kunst Hildesheim/Holzminden/Goettingen, Goettingen (Germany). Fachgebiet Nachhaltige Energie- und Umwelttechnik (NEUTec)

2013-10-01

A highly efficient utilisation of substrates and operational stability at the same time is essential for the efficiency of a biogas plant. The research project SequEx of HAWK and /SF GmbH investigates the increase of efficiency of biogas plants by targeted use of trace elements taking into account bio-availability. Based on sequential extraction diagrams a method for the determination of bio-availability of macro- and micro-nutrients is developed. Within this context, different trace element compounds are analysed during the fermentation process on their share of bioavailable micro-nutrients as well as their effect on the biological activity of microorganisms. The actual knowledge gap between common practice of nutrients' supply and real impact shall be closed by the knowledge base enhancement of the bio-availability of nutrients. (orig.)

Efficient Numeric and Geometric Computations using Heterogeneous Shared Memory Architectures

Science.gov (United States)

2017-10-04

to the memory architectures of CPUs and GPUs to obtain good performance and result in good memory performance using cache management. These methods ...Accomplishments: The PI and students has developed new methods for path and ray tracing and their Report Date: 14-Oct-2017 INVESTIGATOR(S): Phone...The efficiency of our method makes it a good candidate for forming hybrid schemes with wave-based models. One possibility is to couple the ray curve

Trace elements in cigarette tobacco by a method of instrumental neutron activation analysis

International Nuclear Information System (INIS)

Noordin Ibrahim

1986-01-01

A total of ten cigarette brands were investigated for determining the trace elemental concentrations in tobacco so as to assess their role in the induction of related diseases through smoking. A method instrumental Neutron Activation analysis was employed due to high sensitivity, speed and ability to analyse sample for a wide spectrum of elements simultaneously. A total of 18 elements were detected of which the majority are toxic elements. A full result and conclusion will be reported in the forthcoming paper. (A.J.)

Agreement of Tracing and Direct Viewing Techniques for Cervical Vertebral Maturation Assessment.

Science.gov (United States)

Wiwatworakul, Opas; Manosudprasit, Montian; Pisek, Poonsak; Chatrchaiwiwatana, Supaporn; Wangsrimongkol, Tasanee

2015-08-01

This study aimed to evaluate agreement among three methods for cervical vertebral maturation (CVM) assessment, comprising direct viewing, tracing only, and tracing with digitized points. Two examiners received training and tests of reliability with each CVM method before evaluation of agreement among methods. The subjects were 96 female-cleft lateral cephalometric radiographs (films of eight subjects for each age ranged from seven to 18 years). The examiners interpreted CVM stages of the subjects with four-week interval between uses of each method. The range of weighted kappa values for paired comparisons among the three methods were: 0.96-0.98 for direct viewing and tracing only comparison; 0.93-0.94 for direct viewing and tracing with digitized points comparison; and 0.96-0.97 for tracing only and tracing with digitized points comparison. The intraclass correlation coefficient (ICC) value among the three methods was 0.95. These results indicated very good agreement among methods. Use of direct viewing is suitable for CVM assessment without spending more time for tracing. However, the three methods might be used interchangeably.

EPA’s Travel Efficiency Method (TEAM) AMPO Presentation

Science.gov (United States)

Presentation describes EPA’s Travel Efficiency Assessment Method (TEAM) assessing potential travel efficiency strategies for reducing travel activity and emissions, includes reduction estimates in Vehicle Miles Traveled in four different geographic areas.

A sensitive method to extract DNA from biological traces present on ammunition for the purpose of genetic profiling.

Science.gov (United States)

Dieltjes, Patrick; Mieremet, René; Zuniga, Sofia; Kraaijenbrink, Thirsa; Pijpe, Jeroen; de Knijff, Peter

2011-07-01

Exploring technological limits is a common practice in forensic DNA research. Reliable genetic profiling based on only a few cells isolated from trace material retrieved from a crime scene is nowadays more and more the rule rather than the exception. On many crime scenes, cartridges, bullets, and casings (jointly abbreviated as CBCs) are regularly found, and even after firing, these potentially carry trace amounts of biological material. Since 2003, the Forensic Laboratory for DNA Research is routinely involved in the forensic investigation of CBCs in the Netherlands. Reliable DNA profiles were frequently obtained from CBCs and used to match suspects, victims, or other crime scene-related DNA traces. In this paper, we describe the sensitive method developed by us to extract DNA from CBCs. Using PCR-based genotyping of autosomal short tandem repeats, we were able to obtain reliable and reproducible DNA profiles in 163 out of 616 criminal cases (26.5%) and in 283 out of 4,085 individual CBC items (6.9%) during the period January 2003-December 2009. We discuss practical aspects of the method and the sometimes unexpected effects of using cell lysis buffer on the subsequent investigation of striation patterns on CBCs.

Internal standard method for determination of gallium and some trace elements in bauxite by neutron activation analysis

International Nuclear Information System (INIS)

Chen, S.G.; Tsai, H.T.

1983-01-01

A method is described for the determination of gallium and other trace elements such as Ce, Cr, Hf, Lu and Th in bauxite by the technique of neutron activation analysis using gold as internal standard. Isopropyl ether was used as organic extractant radioactive gallium from the sample. This method yields very good accuracy with a relative error of +-3%. (author)

Method of isolation of traces of americium by using the +6 oxidation state properties

International Nuclear Information System (INIS)

Kwinta, Jean; Michel, Jean-Jacques

1969-05-01

The authors present a method to separate traces of americium from a solution containing fission products and actinides. This method comprises the following steps: firstly, the oxidation of americium at the +6 state by ammonium persulfate and carrying over of actinides and III and IV lanthanides by lanthanum fluoride; secondly, the reduction by hydrazine of the oxidized americium and carrying over of the reduced americium by lutetium fluoride; and thirdly, the americium-lutetium separation by selective extractions either with di 2 ethyl hexyl phosphoric acid, or by fractionated elution on an anionic resin column by a mixture of nitric acid and methanol [fr

Temporally rendered automatic cloud extraction (TRACE) system

Science.gov (United States)

Bodrero, Dennis M.; Yale, James G.; Davis, Roger E.; Rollins, John M.

1999-10-01

Smoke/obscurant testing requires that 2D cloud extent be extracted from visible and thermal imagery. These data are used alone or in combination with 2D data from other aspects to make 3D calculations of cloud properties, including dimensions, volume, centroid, travel, and uniformity. Determining cloud extent from imagery has historically been a time-consuming manual process. To reduce time and cost associated with smoke/obscurant data processing, automated methods to extract cloud extent from imagery were investigated. The TRACE system described in this paper was developed and implemented at U.S. Army Dugway Proving Ground, UT by the Science and Technology Corporation--Acuity Imaging Incorporated team with Small Business Innovation Research funding. TRACE uses dynamic background subtraction and 3D fast Fourier transform as primary methods to discriminate the smoke/obscurant cloud from the background. TRACE has been designed to run on a PC-based platform using Windows. The PC-Windows environment was chosen for portability, to give TRACE the maximum flexibility in terms of its interaction with peripheral hardware devices such as video capture boards, removable media drives, network cards, and digital video interfaces. Video for Windows provides all of the necessary tools for the development of the video capture utility in TRACE and allows for interchangeability of video capture boards without any software changes. TRACE is designed to take advantage of future upgrades in all aspects of its component hardware. A comparison of cloud extent determined by TRACE with manual method is included in this paper.

Trace element inhibition of phytase activity.

Science.gov (United States)

Santos, T; Connolly, C; Murphy, R

2015-02-01

Nowadays, 70 % of global monogastric feeds contains an exogenous phytase. Phytase supplementation has enabled a more efficient utilisation of phytate phosphorous (P) and reduction of P pollution. Trace minerals, such as iron (Fe), zinc (Zn), copper (Cu) and manganese (Mn) are essential for maintaining health and immunity as well as being involved in animal growth, production and reproduction. Exogenous sources of phytase and trace elements are regularly supplemented to monogastric diets and usually combined in a premix. However, the possibility for negative interaction between individual components within the premix is high and is often overlooked. Therefore, this initial study focused on assessing the potential in vitro interaction between inorganic and organic chelated sources of Fe, Zn, Cu and Mn with three commercially available phytase preparations. Additionally, this study has investigated if the degree of enzyme inhibition was dependent of the type of chelated sources. A highly significant relationship between phytase inhibition, trace mineral type as well as mineral source and concentration, p phytases for Fe and Zn, as well as for Cu with E. coli and Aspergillus niger phytases. Different chelate trace mineral sources demonstrated diversifying abilities to inhibit exogenous phytase activity.

Application of the nudged elastic band method to the point-to-point radio wave ray tracing in IRI modeled ionosphere

Science.gov (United States)

Nosikov, I. A.; Klimenko, M. V.; Bessarab, P. F.; Zhbankov, G. A.

2017-07-01

Point-to-point ray tracing is an important problem in many fields of science. While direct variational methods where some trajectory is transformed to an optimal one are routinely used in calculations of pathways of seismic waves, chemical reactions, diffusion processes, etc., this approach is not widely known in ionospheric point-to-point ray tracing. We apply the Nudged Elastic Band (NEB) method to a radio wave propagation problem. In the NEB method, a chain of points which gives a discrete representation of the radio wave ray is adjusted iteratively to an optimal configuration satisfying the Fermat's principle, while the endpoints of the trajectory are kept fixed according to the boundary conditions. Transverse displacements define the radio ray trajectory, while springs between the points control their distribution along the ray. The method is applied to a study of point-to-point ionospheric ray tracing, where the propagation medium is obtained with the International Reference Ionosphere model taking into account traveling ionospheric disturbances. A 2-dimensional representation of the optical path functional is developed and used to gain insight into the fundamental difference between high and low rays. We conclude that high and low rays are minima and saddle points of the optical path functional, respectively.

Aerodynamic sampling for landmine trace detection

Science.gov (United States)

Settles, Gary S.; Kester, Douglas A.

2001-10-01

Electronic noses and similar sensors show promise for detecting buried landmines through the explosive trace signals they emit. A key step in this detection is the sampler or sniffer, which acquires the airborne trace signal and presents it to the detector. Practicality demands no physical contact with the ground. Further, both airborne particulates and molecular traces must be sampled. Given a complicated minefield terrain and microclimate, this becomes a daunting chore. Our prior research on canine olfactory aerodynamics revealed several ways that evolution has dealt with such problems: 1) proximity of the sniffer to the scent source is important, 2) avoid exhaling back into the scent source, 3) use an aerodynamic collar on the sniffer inlet, 4) use auxiliary airjets to stir up surface particles, and 5) manage the 'impedance mismatch' between sniffer and sensor airflows carefully. Unfortunately, even basic data on aerodynamic sniffer performance as a function of inlet-tube and scent-source diameters, standoff distance, etc., have not been previously obtained. A laboratory-prototype sniffer was thus developed to provide guidance for landmine trace detectors. Initial experiments with this device are the subject of this paper. For example, a spike in the trace signal is observed upon starting the sniffer airflow, apparently due to rapid depletion of the available signal-laden air. Further, shielding the sniffer from disruptive ambient airflows arises as a key issue in sampling efficiency.

Multiscale optical simulation settings: challenging applications handled with an iterative ray-tracing FDTD interface method.

Science.gov (United States)

Leiner, Claude; Nemitz, Wolfgang; Schweitzer, Susanne; Kuna, Ladislav; Wenzl, Franz P; Hartmann, Paul; Satzinger, Valentin; Sommer, Christian

2016-03-20

We show that with an appropriate combination of two optical simulation techniques-classical ray-tracing and the finite difference time domain method-an optical device containing multiple diffractive and refractive optical elements can be accurately simulated in an iterative simulation approach. We compare the simulation results with experimental measurements of the device to discuss the applicability and accuracy of our iterative simulation procedure.

A simple chemical method for the separation of phosphorus interfering the trace element determinations by neutron activation analysis in high doped silicon wafers

International Nuclear Information System (INIS)

Wagler, H.; Flachowsky, J.

1986-01-01

Neutron activation analysis is one of the most available method for the determination of trace elements, but in the case of P-doped silicon wafers the 32 P-activity interferes the gamma spectrometry. It is not possible to determine the trace elements without chemical manipulations. On the other hand, time consuming chemical separations should be avoided. Therefore, a simple and rapid P-separation method has to be developed, in which the following twelve trace elements should be taken into consideration: Ag, As, Au, Co, Cr, Cu, Fe, Mo, Na, Sb, W, and Zn. After acid oxidative dissolution of the activated sample, P is present as phosphate ion. The phosphate ion is removed by precipitation as BiPO 4 . (author)

Effects of landforms on the erosion rate in a small watershed by the 137Cs tracing method

International Nuclear Information System (INIS)

Li Mian; Yao Wenyi; Li Zhanbin; Liu Puling; Shen Zhenzhou

2010-01-01

It's very important to analyze and evaluate quantitatively the effects of landforms on soil erosion for the prevention and treatment of soil loss in a small watershed. The objective of this study was to evaluate the effects of landform factors on erosion rate by the 137 Cs tracing method in a small watershed in the Purple Hilly Area of China. The erosion rates under different slope lengths, slope gradients and slope aspects were estimated in Xiangshuitan watershed in the Purple Hilly Area in Sichuan Basin by the 137 Cs tracing method. The results showed that the erosion rate decreased exponentially with downslope distance, and it increased with increasing slope gradient during the scope of 5 deg. - 16 deg. The slope aspect had great impact on the erosion rate, and the hillside on the sunny slope had larger erosion rate than that on the shady slope, particularly for the farmland.

Offset Trace-Based Video Quality Evaluation Network Transport

DEFF Research Database (Denmark)

Seeling, P.; Reisslein, M.; Fitzek, Frank

2006-01-01

Video traces contain information about encoded video frames, such as frame sizes and qualities, and provide a convenient method to conduct multimedia networking research. Although wiedely used in networking research, these traces do not allow to determine the video qaulityin an accurate manner...... after networking transport that includes losses and delays. In this work, we provide (i) an overview of frame dependencies that have to be taken into consideration when working with video traces, (ii) an algorithmic approach to combine traditional video traces and offset distortion traces to determine...... the video quality or distortion after lossy network transport, (iii) offset distortion and quality characteristics and (iv) the offset distortion trace format and tools to create offset distortion traces....

Optimum off-line trace synchronization of computer clusters

International Nuclear Information System (INIS)

Jabbarifar, Masoume; Dagenais, Michel; Roy, Robert; Sendi, Alireza Shameli

2012-01-01

A tracing and monitoring framework produces detailed execution trace files for a system. Each trace file contains events with associated timestamps based on the local clock of their respective system, which are not perfectly synchronized. To monitor all behavior in multi-core distributed systems, a global time reference is required, thus the need for traces synchronization techniques. The synchronization is time consuming when there is a cluster of many computers. In this paper we propose an optimized technique to reduce the total synchronization time. Compared with related techniques that have been used on kernel level traces, this method improves the performance while maintaining a high accuracy. It uses the packet rate and the hop count as two major criteria to focus the computation on more accurate network links during synchronization. These criteria, tested in real-word experiments, were identified as most important features of a network. Furthermore, we present numerical and analytical evaluation results, and compare these with previous methods demonstrating the accuracy and the performance of the method.

Comparison of methods for certification of stannic, stibium and lead traces in reference materials for steel

Directory of Open Access Journals (Sweden)

I. V. Khodakovskaya

2016-01-01

Full Text Available Development and introduction of new metallurgical technologies, new additional chemical compound indexes controlled in metallurgical materials demand to develop the new, more advanced methods of analytical control. The particular attention should be paid to identify the traces of stannic, stinium and lead because of their influence on metal characteristics.

A Fast Radiochemical Method for the Determination of Some Essential Trace Elements in Biology and Medicine

Energy Technology Data Exchange (ETDEWEB)

Samsahl, K

1966-02-15

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.

An evaluation of trace element release associated with acid mine drainage

International Nuclear Information System (INIS)

Sullivan, P.J.; Yelton, J.L.

1988-01-01

The determination of trace element release from geologic materials, such as oil shale and coal overburden, is important for proper solid waste management planning. The objective of this study was to determine a correlation between release using the following methods: (1) sequential selective dissolution for determining trace element residencies, (2) toxicity characteristic leaching procedure (TCLP), and (3) humidity cell weathering study simulating maximum trace element release. Two eastern oil shales were used, a New Albany shale that contains 4.6 percent pyrite, and a Chattanooga shale that contains 1.5 percent pyrite. Each shale was analyzed for elemental concentrations by soluble, adsorbed, organic, carbonate, and sulfide phases. The results of the results of the selective dissolution studies show that each trace element has a unique distribution between the various phases. Thus, it is possible to predict trace element release based on trace element residency. The TCLP results show that this method is suitable for assessing soluble trace element release but does not realistically assess potential hazards. The results of the humidity cell studies do demonstrate a more reasonable method for predicting trace element release and potential water quality hazards. The humidity cell methods, however, require months to obtain the required data with a large number of analytical measurements. When the selective dissolution data are compared to the trace element concentrations in the TCLP and humidity cell leachates, it is shown that leachate concentrations are predicted by the selective dissolution data. Therefore, selective dissolution may represent a rapid method to assess trace element release associated with acid mine drainage

Efficiency and stability of the DSBGK method

KAUST Repository

Li, Jun

2012-07-09

Recently, the DSBGK method (Note: the original name DS-BGK is changed to DSBGK for simplicity) was proposed to reduce the stochastic noise in simulating rarefied gas flows at low velocity. Its total computational time is almost independent of the magnitude of deviation from equilibrium state. It was verified by the DSMC method in different benchmark problems over a wide range of Kn number. Some simulation results of the closed lid-driven cavity flow, thermal transpiration flow and the open channel flow by the DSBGK method are given here to show its efficiency and numerical stability. In closed problems, the density distribution is subject to unphysical fluctuation due to the absence of density constraint at the boundary. Thus, many simulated molecules are employed by DSBGK simulations to improve the stability and reduce the magnitude of fluctuation. This increases the memory usage remarkably but has small influence to the efficiency of DSBGK simulations. In open problems, the DSBGK simulation remains stable when using about 10 simulated molecules per cell because the fixed number densities at open boundaries eliminate the unphysical fluctuation. Small modification to the CLL reflection model is introduced to further improve the efficiency slightly.

Efficiency and stability of the DSBGK method

KAUST Repository

Li, Jun

2012-01-01

Recently, the DSBGK method (Note: the original name DS-BGK is changed to DSBGK for simplicity) was proposed to reduce the stochastic noise in simulating rarefied gas flows at low velocity. Its total computational time is almost independent of the magnitude of deviation from equilibrium state. It was verified by the DSMC method in different benchmark problems over a wide range of Kn number. Some simulation results of the closed lid-driven cavity flow, thermal transpiration flow and the open channel flow by the DSBGK method are given here to show its efficiency and numerical stability. In closed problems, the density distribution is subject to unphysical fluctuation due to the absence of density constraint at the boundary. Thus, many simulated molecules are employed by DSBGK simulations to improve the stability and reduce the magnitude of fluctuation. This increases the memory usage remarkably but has small influence to the efficiency of DSBGK simulations. In open problems, the DSBGK simulation remains stable when using about 10 simulated molecules per cell because the fixed number densities at open boundaries eliminate the unphysical fluctuation. Small modification to the CLL reflection model is introduced to further improve the efficiency slightly.

A novel method for trace tritium transport studies

International Nuclear Information System (INIS)

Bonheure, Georges; Mlynar, Jan; Murari, A.; Giroud, C.; Popovichev, S.; Belo, P.; Bertalot, L.

2009-01-01

A new method combining a free-form solution for the neutron emissivity and the ratio method (Bonheure et al 2006 Nucl. Fusion 46 725-40) is applied to the investigation of tritium particle transport in JET plasmas. The 2D neutron emissivity is calculated using the minimum Fisher regularization method (MFR) (Anton et al 1996 Plasma Phys. Control. Fusion 38 1849, Mlynar et al 2003 Plasma Phys. Control. Fusion 45 169). This method is being developed and studied alongside other methods at JET. The 2D neutron emissivity was significantly improved compared with the first MFR results by constraining the emissivity along the magnetic flux surfaces. 1D profiles suitable for transport analysis are then obtained by subsequent poloidal integration. In methods on which previous JET publications are based (Stork et al 2005 Nucl. Fusion 45 S181, JET Team (prepared by Zastrow) 1999 Nucl. Fusion 39 1891, Zastrow et al 2004 Plasma Phys. Control. Fusion 46 B255, Adams et al 1993 Nucl. Instrum. Methods A 329 277, Jarvis et al 1997 Fusion Eng. Des. 34-35 59, Jarvis et al 1994 Plasma Phys. Control. Fusion 36 219), the 14.07 MeV D-T neutron line integrals measurements were simulated and the transport coefficients varied until good fits were obtained. In this novel approach, direct knowledge of tritium concentration or the fuel ratio n T /n D is obtained using all available neutron profile information, e.g both 2.45 MeV D-D neutron profiles and 14.07 MeV D-T neutron profiles (Bonheure et al 2006 Nucl.Fusion 46 725-40). Tritium particle transport coefficients are then determined using a linear regression from the dynamic response of the tritium concentration n T /n D profile. The temporal and spatial evolution of tritium particle concentration was studied for a set of JET discharges with tritium gas puffs from the JET trace tritium experiments. Local tritium transport coefficients were derived from the particle flux equation Γ = -D∇n T + Vn T , where D is the particle diffusivity and V

Informative importance of determination of trace elements in biologocal mediums in patients with endocrine pathology

Directory of Open Access Journals (Sweden)

Ирина Николаевна Андрусишина

2015-07-01

Full Text Available Aim. The changes of mineral metabolism in human organism caused by the deficiency or excess of trace elements in environment (air, food stuffs, water can lead to disorder of functional status of organism.An excess or deficiency of the certain metals disturb the balance of metabolic processes in organism that causes the different changes in endocrine system too. That is why the aim of research was to detect the peculiarities of distribution of macro and trace elements in patients with different endocrine pathology and to show the reasonability of the complex approach in assessment of microelementoses at hyperthyroidism and diabetes mellitus.Methods. The balance of 15 macro and trace elements in different biological mediums (hairs, whole blood, blood serum, urine was studied using EAAS and AES-ICP methods.Result. There was demonstrated the high informative importance of determination of K, Mg, Mn, Cr, Zn at pancreas pathology and Cr, Mn, Se, Zn- at thyroid pathology in human. There was detected that endocrine pathology is characterized with the surplus accumulation of Al, As and Pb in organism of examined patients.Conclusions. To increase the reliability and efficiency of the clinical diagnostics of endocrine human pathology there was demonstrated the high informative importance of the complex approach in choice of biological mediums at assessment of the trace elements imbalance. 

Application of the radioreagent method to the determination of trace quantities of lead

International Nuclear Information System (INIS)

Figueiredo, A.M.G.; Saiki, M.; Lima, F.W. de

1983-01-01

The radioreagent method of analysis was applied to determine trace quantities of lead in several types of samples. This method is based on the extraction of radioactive cobalt, displaced by lead from the cobalt chelate of ethylenediaminetetraacetate labeled with 60 Co, into a tetracycline-benzyl alcohol solution. The radioactivity of the released cobalt, extracted into the organic phase, measured by menas of a single channel gamma-ray analyzer coupled to a Na(T1) scintillation detector, is proportional to the lead concentration. The elements which might interfere with the analysis were removed by a chemical separation procedure of lead using dithizone. The method was applied for lead determination in air samples, gasoline and samples from the International Atomic Energy Agency, namely: simulated air filter (Air-3), fresh water (W-3), dried animal whole blood(A-2) and calcinated animal bone (A3/1). The sensitivity, accuracy and precision of the method were also discussed. (Author) [pt

Application of the neutron activation analysis method for determing trace elements in Brazilian food sample

International Nuclear Information System (INIS)

Maihara, V.A.; Vasconcellos, M.B.A.

1988-01-01

Recently there has been an increase of consciousness about the importance of trace elements in human health and disease as well as rising concern about food contamination. The development of sensitive, accurate and price methods is one of the most important of the knowledge of trace elements contents in foods and in biological samples. Neutron activation analysis is one of the most suitable tecniques because a great number of elements can be determined in concentrations in the range of μg/g to ng/g. The present work is a part of an AIEA Co-ordinated Research Programme on the applications of nuclear techniques for toxic elements in foodstuffs. Neutron activation analysis is applied to analysis of bread, milk powder and rice that are considered essential foods in the Brazilian diet. Some aspects of the activation analysis of biological matrices are discussed. (author) [pt

Efficient methods of piping cleaning

Directory of Open Access Journals (Sweden)

Orlov Vladimir Aleksandrovich

2014-01-01

Full Text Available The article contains the analysis of the efficient methods of piping cleaning of water supply and sanitation systems. Special attention is paid to the ice cleaning method, in course of which biological foil and various mineral and organic deposits are removed due to the ice crust buildup on the inner surface of water supply and drainage pipes. These impurities are responsible for the deterioration of the organoleptic properties of the transported drinking water or narrowing cross-section of drainage pipes. The co-authors emphasize that the use of ice compared to other methods of pipe cleaning has a number of advantages due to the relative simplicity and cheapness of the process, economical efficiency and lack of environmental risk. The equipment for performing ice cleaning is presented, its technological options, terms of cleansing operations, as well as the volumes of disposed pollution per unit length of the water supply and drainage pipelines. It is noted that ice cleaning requires careful planning in the process of cooking ice and in the process of its supply in the pipe. There are specific requirements to its quality. In particular, when you clean drinking water system the ice applied should be hygienically clean and meet sanitary requirements.In pilot projects, in particular, quantitative and qualitative analysis of sediments adsorbed by ice is conducted, as well as temperature and the duration of the process. The degree of pollution of the pipeline was estimated by the volume of the remote sediment on 1 km of pipeline. Cleaning pipelines using ice can be considered one of the methods of trenchless technologies, being a significant alternative to traditional methods of cleaning the pipes. The method can be applied in urban pipeline systems of drinking water supply for the diameters of 100—600 mm, and also to diversion collectors. In the world today 450 km of pipelines are subject to ice cleaning method.Ice cleaning method is simple

Electricity transmission pricing: Tracing based point-of-connection tariff

International Nuclear Information System (INIS)

Abhyankar, A.R.; Khaparde, S.A.

2009-01-01

Point-of-connection (POC) scheme of transmission pricing in decentralized markets charges the participants a single rate per MW depending on their point-of-connection. Use of grossly aggregated postage stamp rates as POC charges fails to provide appropriate price signals. The POC tariff based on distribution of network sunk costs by employing conventional tracing assures recovery of sunk costs based on extent of use of network by participants. However, the POC tariff by this method does not accommodate economically efficient price signals which correspond to marginal costs. On the other hand, the POC tariff, if made proportional to marginal costs alone, fails to account for sunk costs and extent of use of network. This paper overcomes these lacunae by combining the above stated desired objectives under the recently proposed optimal tracing framework. Since real power tracing problem is amenable to multiple solutions, it is formulated as linearly constrained optimization problem. By employing this methodology, consideration of extent of network use and sunk cost recovery are guaranteed, while objective function is designed such that the spatial pattern of price signals closely follows the pattern of scaled locational marginal prices. The methodology is tested on IEEE 30 bus system, wherein average power flow pattern is established by running various simulation states on congested and un-congested network conditions. (author)

An Efficient Vital Area Identification Method

International Nuclear Information System (INIS)

Jung, Woo Sik

2017-01-01

A new Vital Area Identification (VAI) method was developed in this study for minimizing the burden of VAI procedure. It was accomplished by performing simplification of sabotage event trees or Probabilistic Safety Assessment (PSA) event trees at the very first stage of VAI procedure. Target sets and prevention sets are calculated from the sabotage fault tree. The rooms in the shortest (most economical) prevention set are selected and protected as vital areas. All physical protection is emphasized to protect these vital areas. All rooms in the protected area, the sabotage of which could lead to core damage, should be incorporated into sabotage fault tree. So, sabotage fault tree development is a very difficult task that requires high engineering costs. IAEA published INFCIRC/225/Rev.5 in 2011 which includes principal international guidelines for the physical protection of nuclear material and nuclear installations. A new efficient VAI method was developed and demonstrated in this study. Since this method drastically reduces VAI problem size, it provides very quick and economical VAI procedure. A consistent and integrated VAI procedure had been developed by taking advantage of PSA results, and more efficient VAI method was further developed in this study by inserting PSA event tree simplification at the initial stage of VAI procedure.

Effect of parameters in moving average method for event detection enhancement using phase sensitive OTDR

Science.gov (United States)

Kwon, Yong-Seok; Naeem, Khurram; Jeon, Min Yong; Kwon, Il-bum

2017-04-01

We analyze the relations of parameters in moving average method to enhance the event detectability of phase sensitive optical time domain reflectometer (OTDR). If the external events have unique frequency of vibration, then the control parameters of moving average method should be optimized in order to detect these events efficiently. A phase sensitive OTDR was implemented by a pulsed light source, which is composed of a laser diode, a semiconductor optical amplifier, an erbium-doped fiber amplifier, a fiber Bragg grating filter, and a light receiving part, which has a photo-detector and high speed data acquisition system. The moving average method is operated with the control parameters: total number of raw traces, M, number of averaged traces, N, and step size of moving, n. The raw traces are obtained by the phase sensitive OTDR with sound signals generated by a speaker. Using these trace data, the relation of the control parameters is analyzed. In the result, if the event signal has one frequency, then the optimal values of N, n are existed to detect the event efficiently.

Trace elements as paradigms of developmental neurotoxicants

DEFF Research Database (Denmark)

Grandjean, Philippe; Herz, Katherine T

2015-01-01

Trace elements have contributed unique insights into developmental neurotoxicity and serve as paradigms for such adverse effects. Many trace elements are retained in the body for long periods and can be easily measured to assess exposure by inexpensive analytical methods that became available...

Trace radioactive measurement in foodstuffs using high purity germanium detector

International Nuclear Information System (INIS)

Morco, Ryan P.; Racho, Joseph Michael D.; Castaneda, Soledad S.; Almoneda, Rosalina V.; Pabroa, Preciosa Corazon B.; Sucgang, Raymond J.

2010-01-01

Trace radioactivity in food has been seriously considered sources of potential harm after the accidental radioactive releases in the last decades which led to contamination of the food chain. Countermeasures are being used to reduce the radiological health risk to the population and to ensure that public safety and international commitments are met. Investigation of radioactive traces in foods was carried out by gamma-ray spectrometry. The radionuclides being measured were fission products 1 37Cs and 1 34Cs and naturally occurring 4 0Κ. Gamma-ray measurements were performed using a hybrid gamma-ray counting system with coaxial p-type Tennelec High Purity Germanium (HPGe) detector with relative efficiency of 18.4%. Channels were calibrated to energies using a standard check source with 1 37Cs and 6 0Co present. Self-shielding within samples was taken into account by comparing directly with reference standards of similar matrix and geometry. Efficiencies of radionuclides of interests were accounted in calculating the activity concentrations in the samples. Efficiency calibration curve was generated using an in-house validated program called FINDPEAK, a least-square method that fits a polynomial up to sixth-order of equation. Lower Limits of Detection (LLD) obtained for both 1 37Cs and 1 34Cs ranges from 1-6 Bq/Kg depending on the sample matrix. In the last five years, there have been no foodstuffs analyzed exceeded the local and international regulatory limit of 1000Bq/Kg for the summed activities of 1 37Cs and 1 34Cs. (author)

RAY TRACING IMPLEMENTATION IN JAVA PROGRAMMING LANGUAGE

Directory of Open Access Journals (Sweden)

Aybars UĞUR

2002-01-01

Full Text Available In this paper realism in computer graphics and components providing realism are discussed at first. It is mentioned about illumination models, surface rendering methods and light sources for this aim. After that, ray tracing which is a technique for creating two dimensional image of a three-dimensional virtual environment is explained briefly. A simple ray tracing algorithm was given. "SahneIzle" which is a ray tracing program implemented in Java programming language which can be used on the internet is introduced. As a result, importance of network-centric ray tracing software is discussed.

GTSO: Global Trace Synchronization and Ordering Mechanism for Wireless Sensor Network Monitoring Platforms.

Science.gov (United States)

Navia, Marlon; Campelo, José Carlos; Bonastre, Alberto; Ors, Rafael

2017-12-23

Monitoring is one of the best ways to evaluate the behavior of computer systems. When the monitored system is a distributed system-such as a wireless sensor network (WSN)-the monitoring operation must also be distributed, providing a distributed trace for further analysis. The temporal sequence of occurrence of the events registered by the distributed monitoring platform (DMP) must be correctly established to provide cause-effect relationships between them, so the logs obtained in different monitor nodes must be synchronized. Many of synchronization mechanisms applied to DMPs consist in adjusting the internal clocks of the nodes to the same value as a reference time. However, these mechanisms can create an incoherent event sequence. This article presents a new method to achieve global synchronization of the traces obtained in a DMP. It is based on periodic synchronization signals that are received by the monitor nodes and logged along with the recorded events. This mechanism processes all traces and generates a global post-synchronized trace by scaling all times registered proportionally according with the synchronization signals. It is intended to be a simple but efficient offline mechanism. Its application in a WSN-DMP demonstrates that it guarantees a correct ordering of the events, avoiding the aforementioned issues.

GTSO: Global Trace Synchronization and Ordering Mechanism for Wireless Sensor Network Monitoring Platforms

Science.gov (United States)

Bonastre, Alberto; Ors, Rafael

2017-01-01

Monitoring is one of the best ways to evaluate the behavior of computer systems. When the monitored system is a distributed system—such as a wireless sensor network (WSN)—the monitoring operation must also be distributed, providing a distributed trace for further analysis. The temporal sequence of occurrence of the events registered by the distributed monitoring platform (DMP) must be correctly established to provide cause-effect relationships between them, so the logs obtained in different monitor nodes must be synchronized. Many of synchronization mechanisms applied to DMPs consist in adjusting the internal clocks of the nodes to the same value as a reference time. However, these mechanisms can create an incoherent event sequence. This article presents a new method to achieve global synchronization of the traces obtained in a DMP. It is based on periodic synchronization signals that are received by the monitor nodes and logged along with the recorded events. This mechanism processes all traces and generates a global post-synchronized trace by scaling all times registered proportionally according with the synchronization signals. It is intended to be a simple but efficient offline mechanism. Its application in a WSN-DMP demonstrates that it guarantees a correct ordering of the events, avoiding the aforementioned issues. PMID:29295494

RAY TRACING IMPLEMENTATION IN JAVA PROGRAMMING LANGUAGE

OpenAIRE

Aybars UĞUR; Mustafa TÜRKSEVER

2002-01-01

In this paper realism in computer graphics and components providing realism are discussed at first. It is mentioned about illumination models, surface rendering methods and light sources for this aim. After that, ray tracing which is a technique for creating two dimensional image of a three-dimensional virtual environment is explained briefly. A simple ray tracing algorithm was given. "SahneIzle" which is a ray tracing program implemented in Java programming language which ...

Application of environmental isotope tracing technology to geothermal geochemistry

International Nuclear Information System (INIS)

Shang Yingnan

2006-01-01

This paper reviews the recent application and development of environmental isotope tracing technology to geothermal geochemistry in the following aspects: gas isotopes (He, C) tracing of warm springs; H, O isotope tracing on the origin and cause of geothermal water, environmental isotope dating of geothermal water, and the advantage of excess parameter of deuterium (d) in geothermal research. The author also suggests that isotope method should combine with other geological methods to expand its advantage. (authors)

Kinetic method of ruthenium ion traces determination, basing on the reaction of oxidation of direct blue 6B, by means of hydrogen peroxide

International Nuclear Information System (INIS)

Suwinska, T.; Gregorowicz, A.; Matysek-Majewska, D.

1980-01-01

A sensitive and selective method of determination of ruthenium ion traces (1.10 - 3 μg/cm 3 ) has been worked out. The method is based on oxidation of direct blue 6B by hydrogen peroxide under acidic conditions at pH = 0,8 - 1,2 in the presence of ruthenium ions as catalyst. The method has been applied for determination of ruthenium traces in Pt, PdCl 2 , PtCl 4 and RhCl 3 .n H 2 O. In these materials ruthenium has been determined within the range of 1,10 - 2 % - 5,10 - 4 %. (author)

Division of methods for counting helminths’ eggs and the problem of efficiency of these methods

Directory of Open Access Journals (Sweden)

Katarzyna Jaromin-Gleń

2017-03-01

Full Text Available From the sanitary and epidemiological aspects, information concerning the developmental forms of intestinal parasites, especially the eggs of helminths present in our environment in: water, soil, sandpits, sewage sludge, crops watered with wastewater are very important. The methods described in the relevant literature may be classified in various ways, primarily according to the methodology of the preparation of samples from environmental matrices prepared for analysis, and the sole methods of counting and chambers/instruments used for this purpose. In addition, there is a possibility to perform the classification of the research methods analyzed from the aspect of the method and time of identification of the individuals counted, or the necessity for staining them. Standard methods for identification of helminths’ eggs from environmental matrices are usually characterized by low efficiency, i.e. from 30% to approximately 80%. The efficiency of the method applied may be measured in a dual way, either by using the method of internal standard or the ‘Split/Spike’ method. While measuring simultaneously in an examined object the efficiency of the method and the number of eggs, the ‘actual’ number of eggs may be calculated by multiplying the obtained value of the discovered eggs of helminths by inverse efficiency.

Opo lidar sounding of trace atmospheric gases in the 3 - 4 μm spectral range

Science.gov (United States)

Romanovskii, Oleg A.; Sadovnikov, Sergey A.; Kharchenko, Olga V.; Yakovlev, Semen V.

2018-04-01

The applicability of a KTA crystal-based laser system with optical parametric oscillators (OPO) generation to lidar sounding of the atmosphere in the spectral range 3-4 μm is studied in this work. A technique developed for lidar sounding of trace atmospheric gases (TAG) is based on differential absorption lidar (DIAL) method and differential optical absorption spectroscopy (DOAS). The DIAL-DOAS technique is tested to estimate its efficiency for lidar sounding of atmospheric trace gases. The numerical simulation performed shows that a KTA-based OPO laser is a promising source of radiation for remote DIAL-DOAS sounding of the TAGs under study along surface tropospheric paths. A possibility of using a PD38-03-PR photodiode for the DIAL gas analysis of the atmosphere is shown.

Major and trace elements in mouse bone measured by surface and bulk sensitive methods

International Nuclear Information System (INIS)

Benkoe, I.; Geresi, K.; Ungvari, E.; Szabo, B.; Paripas, B.

2011-01-01

Complete text of publication follows. In the past years an increasing research interest turned to the accurate determination of the components of bone samples. These investigations focused on both the major and trace elements in the bone. Work in this field is strongly motivated because various major and trace element concentrations can be good indicators of several diseases. Number of studies also focused on the determination of the components both in the organic and inorganic parts of the bone separately, because they both have role during bone remodeling processes. Also important to note that bone can be one of the final destinations in the body where toxic elements are deposited. In this work we performed various surface and bulk sensitive analyses for the mouse bone samples to determine its major and trace element components. We have shown concentration profiles for various major and observable trace elements of the mouse bone. We found, in accordance with our expectation, that the mostly surface sensitive XPS technique is not suitable to determine the concentration of the trace elements in bone samples. It was also shown that XPS is a valuable tool not only in the determination of the chemical states of the major components of the bone powder but in the quantitative determination of their relative concentrations. Both the major and the trace elements of the bone samples are determined using PIXE and SNMS spectra. Although the information depths are very different for PIXE (a few tens of micrometer) and for XPS analysis (a few nanometers), our present PIXE result, using the bone sample in its original form for the concentration ratio between Ca and P is in excellent agreement with the XPS results using calcinated mouse bone powder. Discrepancy in Ca/Mg ratio (PIXE: 35.7 and XPS: 12.7) maybe due to many factors, which influence this ratio in bone samples. In the case of PIXE we studied native bones and determined composition of the compact bone at outside

A Fast Radiochemical Method for the Determination of Some Essential Trace Elements in Biology and Medicine

International Nuclear Information System (INIS)

Samsahl, K.

1964-12-01

A method has been developed for the determination with neutron-activation analysis of the following trace elements in soft biological tissues: Br, Ca, Cl, Cu, K, Mg, Mn, Mo, Na, P, Sr and Zn. The method consists in performing a short-term irradiation of the samples with a high thermal neutron flux, followed by fast chemical separations and gamma-spectrometric measurements. The chemical separations and the measurements of short-lived nuclides from a run are finished within 70 min, after the end of irradiation

A Fast Radiochemical Method for the Determination of Some Essential Trace Elements in Biology and Medicine

Energy Technology Data Exchange (ETDEWEB)

Samsahl, K

1964-12-15

A method has been developed for the determination with neutron-activation analysis of the following trace elements in soft biological tissues: Br, Ca, Cl, Cu, K, Mg, Mn, Mo, Na, P, Sr and Zn. The method consists in performing a short-term irradiation of the samples with a high thermal neutron flux, followed by fast chemical separations and gamma-spectrometric measurements. The chemical separations and the measurements of short-lived nuclides from a run are finished within 70 min, after the end of irradiation.

Development of an Origin Trace Method based on Bayesian Inference and Artificial Neural Network for Missing or Stolen Nuclear Materials

Energy Technology Data Exchange (ETDEWEB)

Bin, Yim Ho; Min, Lee Seung; Min, Kim Kyung; Jeong, Hong Yoon; Kim, Jae Kwang [Nuclear Security Div., Daejeon (Korea, Republic of)

2014-05-15

Thus, 'to put nuclear materials under control' is an important issue for prosperity mankind. Unfortunately, numbers of illicit trafficking of nuclear materials have been increased for decades. Consequently, security of nuclear materials is recently spotlighted. After the 2{sup nd} Nuclear Security Summit in Seoul in 2012, the president of Korea had showed his devotion to nuclear security. One of the main responses for nuclear security related interest of Korea was to develop a national nuclear forensic support system. International Atomic Energy Agency (IAEA) published the document of Nuclear Security Series No.2 'Nuclear Forensics Support' in 2006 to encourage international cooperation of all IAEA member states for tracking nuclear attributions. There are two main questions related to nuclear forensics to answer in the document. The first question is 'what type of material is it?', and the second one is 'where did the material come from?' Korea Nuclear Forensic Library (K-NFL) and mathematical methods to trace origins of missing or stolen nuclear materials (MSNMs) are being developed by Korea Institute of Nuclear Non-proliferation and Control (KINAC) to answer those questions. Although the K-NFL has been designed to perform many functions, K-NFL is being developed to effectively trace the origin of MSNMs and tested to validate suitability of trace methods. New fuels and spent fuels need each trace method because of the different nature of data acquisition. An inductive logic was found to be appropriate for new fuels, which had values as well as a bistable property. On the other hand, machine learning was suitable for spent fuels, which were unable to measure, and thus needed simulation.

Traces of Teaching Methods in a Language Class and the Relationship between Teachers' Intended Learning Outcomes and Students' Uptake

Science.gov (United States)

Mahmoudabadi, Zahra

2017-01-01

This study has two main objectives: first, to find traces of teaching methods in a language class and second, to study the relationship between intended learning outcomes and uptake, which is defined as what students claim to have learned. In order to identify the teaching method, after five sessions of observation, class activities and procedures…

A method for speciation of trace elements (stable and radioactive) in natural waters

International Nuclear Information System (INIS)

Salbu, B.; Bjoernstad, H.E.; Pappas, A.C.

1986-01-01

The interaction of radionuclides and trace metals with colloids changes their size and charge characteristics and thereby influences their transport, mobility and bioavailability. In order to investigate the role of colloids as transport agents for radionuclides or trace elements, a continuous mixing and separation system, using hollow fiber cartridges has been developed. This system allows the association of traces with naturally occurring colloids of a given size distribution to be followed and information on the degree of binding, binding constants and number of sorption sites can be obtained. Based on diffusion rate measurements using the hollow fibres, the molecular weight of species diffusing through membranes can also be estimated. (author)

Chapter 1: Introduction. The Uniform Methods Project: Methods for Determining Energy-Efficiency Savings for Specific Measures

Energy Technology Data Exchange (ETDEWEB)

Li, Michael [Dept. of Energy (DOE), Washington DC (United States). Office of Energy Efficiency and Renewable Energy; Haeri, Hossein [The Cadmus Group, Portland, OR (United States); Reynolds, Arlis [The Cadmus Group, Portland, OR (United States)

2017-09-28

This chapter provides a set of model protocols for determining energy and demand savings that result from specific energy efficiency measures implemented through state and utility efficiency programs. The methods described here are approaches that are or are among the most commonly used and accepted in the energy efficiency industry for certain measures or programs. As such, they draw from the existing body of research and best practices for energy efficiency program evaluation, measurement, and verification (EM&V). These protocols were developed as part of the Uniform Methods Project (UMP), funded by the U.S. Department of Energy (DOE). The principal objective for the project was to establish easy-to-follow protocols based on commonly accepted methods for a core set of widely deployed energy efficiency measures.

Combination of flame atomic absorption spectrometry with ligandless-dispersive liquid- liquid microextraction for preconcentration and determination of trace amount of lead in water samples

Directory of Open Access Journals (Sweden)

Y.M. Baghelani

2013-05-01

Full Text Available A new ligandless-dispersive liquid–liquid microextraction method has been developed for the separation and flame atomic absorption spectrometry determination of trace amount of lead(II ion. In the proposed approach 1,2-dicholorobenzene and ethanol were used as extraction and dispersive solvents. Factors influencing the extraction efficiency of lead, including the extraction and dispersive solvent type and volume, pH of sample solution, concentration of chloride and extraction time were studied. Under the optimal conditions, the calibration curve was linear in the range of 7.0–6000 ng mL−1 of lead with R2 = 0.9992 (n = 10 and detection limit based on three times the standard deviation of the blank (3Sb was 0.5 ng mL−1 in original solution. The relative standard deviation for eight replicate determinations of 1.0 mg mL-1 lead was ±1.6%. The high efficiency of dispersive liquid-liquid microextraction to carry out the determination of trace amounts of lead in complex matrices was demonstrated. The proposed method has been applied for determination of trace amounts of lead in water samples and satisfactory results were obtained. The accuracy was checked by analyzing a certified reference material from the National Institute of Standard and Technology, Trace elements in water (NIST CRM 1643e.

Efficient and robust implementation of the TLISMNI method

Science.gov (United States)

Aboubakr, Ahmed K.; Shabana, Ahmed A.

2015-09-01

The dynamics of large scale and complex multibody systems (MBS) that include flexible bodies and contact/impact pairs is governed by stiff equations. Because explicit integration methods can be inefficient and often fail in the case of stiff problems, the use of implicit numerical integration methods is recommended in this case. This paper presents a new and efficient implementation of the two-loop implicit sparse matrix numerical integration (TLISMNI) method proposed for the solution of constrained rigid and flexible MBS differential and algebraic equations. The TLISMNI method has desirable features that include avoiding numerical differentiation of the forces, allowing for an efficient sparse matrix implementation, and ensuring that the kinematic constraint equations are satisfied at the position, velocity and acceleration levels. In this method, a sparse Lagrangian augmented form of the equations of motion that ensures that the constraints are satisfied at the acceleration level is used to solve for all the accelerations and Lagrange multipliers. The generalized coordinate partitioning or recursive methods can be used to satisfy the constraint equations at the position and velocity levels. In order to improve the efficiency and robustness of the TLISMNI method, the simple iteration and the Jacobian-Free Newton-Krylov approaches are used in this investigation. The new implementation is tested using several low order formulas that include Hilber-Hughes-Taylor (HHT), L-stable Park, A-stable Trapezoidal, and A-stable BDF methods. The HHT method allows for including numerical damping. Discussion on which method is more appropriate to use for a certain application is provided. The paper also discusses TLISMNI implementation issues including the step size selection, the convergence criteria, the error control, and the effect of the numerical damping. The use of the computer algorithm described in this paper is demonstrated by solving complex rigid and flexible tracked

Coacervative extraction of trace lead from natural waters prior to its determination by electrothermal atomic absorption spectrometry

Energy Technology Data Exchange (ETDEWEB)

Hagarová, Ingrid, E-mail: hagarova@fns.uniba.sk; Bujdoš, Marek; Matúš, Peter; Kubová, Jana

2013-10-01

In this work, a relatively simple and sensitive method for separation/preconcentration of trace lead from natural waters prior to its determination by electrothermal atomic absorption spectrometry has been proposed. The method is based on the extraction of Pb–dithizone chelate with coacervates made up of lauric acid in the presence of potassium ions and methanol. Several important factors affecting extraction efficiency such as pH, concentration of lauric acid and dithizone, ionic strength, incubation and centrifugation time were investigated and optimized. After separation of aqueous bulk solution from surfactant-rich phase, the final extract was redissolved by using 500 μl of methanol acidified with 0.2 mol l{sup −1} HNO{sub 3}. Under the optimized conditions (using initial sample volume of 10 ml), enrichment factor of 17.0, detection limit of 0.12 μg l{sup −1}, quantification limit of 0.38 μg l{sup −1}, relative standard deviation of 4.2% (for 2 μg l{sup −1} of Pb; n = 26), linearity of the calibration graph in the range of 0.5–4.0 μg l{sup −1} (with correlation coefficient better than 0.995) were achieved. The method was validated by the analysis of certified reference material (TMDA-61). Extraction recoveries for the CRM, spiked model solutions and spiked natural water samples were in the range of 91–96%. Finally, the method was applied to the separation/preconcentration and determination of trace lead in natural waters. - Highlights: • The potential of coacervates for the extraction of metal ions is examined. • No difficulties in coupling of ETAAS with the proposed CAE are observed. • Achieved preconcentration factor results in enhanced sensitivity. • Analytical performance is confirmed by the reliable determination of trace Pb. • The proposed CAE is ecofriendly and efficient.

Remediation using trace element humate surfactant

Energy Technology Data Exchange (ETDEWEB)

Riddle, Catherine Lynn; Taylor, Steven Cheney; Bruhn, Debra Fox

2016-08-30

A method of remediation at a remediation site having one or more undesirable conditions in which one or more soil characteristics, preferably soil pH and/or elemental concentrations, are measured at a remediation site. A trace element humate surfactant composition is prepared comprising a humate solution, element solution and at least one surfactant. The prepared trace element humate surfactant composition is then dispensed onto the remediation site whereby the trace element humate surfactant composition will reduce the amount of undesirable compounds by promoting growth of native species activity. By promoting native species activity, remediation occurs quickly and environmental impact is minimal.

Sampling and sample preparation methods for the analysis of trace elements in biological material

International Nuclear Information System (INIS)

Sansoni, B.; Iyengar, V.

1978-05-01

The authors attempt to give a most systamtic possible treatment of the sample taking and sample preparation of biological material (particularly in human medicine) for trace analysis (e.g. neutron activation analysis, atomic absorption spectrometry). Contamination and loss problems are discussed as well as the manifold problems of the different consistency of solid and liquid biological materials, as well as the stabilization of the sample material. The process of dry and wet ashing is particularly dealt with, where new methods are also described. (RB) [de

ASSESSMENT OF THE EFFICIENCY OF DISINFECTION METHOD ...

African Journals Online (AJOL)

eobe

ABSTRACT. The efficiencies of three disinfection methods namely boiling, water guard and pur purifier were assessed. ... Water is an indispensable resource for supporting life systems [2- ...... developing country context: improving decisions.

Computation and analysis of backward ray-tracing in aero-optics flow fields.

Science.gov (United States)

Xu, Liang; Xue, Deting; Lv, Xiaoyi

2018-01-08

A backward ray-tracing method is proposed for aero-optics simulation. Different from forward tracing, the backward tracing direction is from the internal sensor to the distant target. Along this direction, the tracing in turn goes through the internal gas region, the aero-optics flow field, and the freestream. The coordinate value, the density, and the refractive index are calculated at each tracing step. A stopping criterion is developed to ensure the tracing stops at the outer edge of the aero-optics flow field. As a demonstration, the analysis is carried out for a typical blunt nosed vehicle. The backward tracing method and stopping criterion greatly simplify the ray-tracing computations in the aero-optics flow field, and they can be extended to our active laser illumination aero-optics study because of the reciprocity principle.

Effective removal of hazardous trace metals from recovery boiler fly ashes.

Science.gov (United States)

Kinnarinen, Teemu; Golmaei, Mohammad; Jernström, Eeva; Häkkinen, Antti

2018-02-15

The objective of this study is to introduce a treatment sequence enabling straightforward and effective recovery of hazardous trace elements from recovery boiler fly ash (RBFA) by a novel method, and to demonstrate the subsequent removal of Cl and K with the existing crystallization technology. The treatment sequence comprises two stages: dissolution of most other RBFA components than the hazardous trace elements in water in Step 1 of the treatment, and crystallization of the process chemicals in Step 2. Solid-liquid separation has an important role in the treatment, due to the need to separate first the small solid residue containing the trace elements, and to separate the valuable crystals, containing Na and S, from the liquid rich in Cl and K. According to the results, nearly complete recovery of cadmium, lead and zinc can be reached even without pH adjustment. Some other metals, such as Mg and Mn, are removed together with the hazardous metals. Regarding the removal of Cl and K from the process, in this non-optimized case the removal efficiency was satisfactory: 60-70% for K when 80% of sodium was recovered, and close to 70% for Cl when 80% of sulfate was recovered. Copyright © 2017 Elsevier B.V. All rights reserved.

Integrated method for the measurement of trace nitrogenous atmospheric bases

Directory of Open Access Journals (Sweden)

D. Key

2011-12-01

Full Text Available Nitrogenous atmospheric bases are thought to play a key role in the global nitrogen cycle, but their sources, transport, and sinks remain poorly understood. Of the many methods available to measure such compounds in ambient air, few meet the current need of being applicable to the complete range of potential analytes and fewer still are convenient to implement using instrumentation that is standard to most laboratories. In this work, an integrated approach to measuring trace, atmospheric, gaseous nitrogenous bases has been developed and validated. The method uses a simple acid scrubbing step to capture and concentrate the bases as their phosphite salts, which then are derivatized and analyzed using GC/MS and/or LC/MS. The advantages of both techniques in the context of the present measurements are discussed. The approach is sensitive, selective, reproducible, as well as convenient to implement and has been validated for different sampling strategies. The limits of detection for the families of tested compounds are suitable for ambient measurement applications (e.g., methylamine, 1 pptv; ethylamine, 2 pptv; morpholine, 1 pptv; aniline, 1 pptv; hydrazine, 0.1 pptv; methylhydrazine, 2 pptv, as supported by field measurements in an urban park and in the exhaust of on-road vehicles.

An efficient unstructured WENO method for supersonic reactive flows

Science.gov (United States)

Zhao, Wen-Geng; Zheng, Hong-Wei; Liu, Feng-Jun; Shi, Xiao-Tian; Gao, Jun; Hu, Ning; Lv, Meng; Chen, Si-Cong; Zhao, Hong-Da

2018-03-01

An efficient high-order numerical method for supersonic reactive flows is proposed in this article. The reactive source term and convection term are solved separately by splitting scheme. In the reaction step, an adaptive time-step method is presented, which can improve the efficiency greatly. In the convection step, a third-order accurate weighted essentially non-oscillatory (WENO) method is adopted to reconstruct the solution in the unstructured grids. Numerical results show that our new method can capture the correct propagation speed of the detonation wave exactly even in coarse grids, while high order accuracy can be achieved in the smooth region. In addition, the proposed adaptive splitting method can reduce the computational cost greatly compared with the traditional splitting method.

Methods for optimizing over the efficient and weakly efficient sets of an affine fractional vector optimization program

DEFF Research Database (Denmark)

Le, T.H.A.; Pham, D. T.; Canh, Nam Nguyen

2010-01-01

Both the efficient and weakly efficient sets of an affine fractional vector optimization problem, in general, are neither convex nor given explicitly. Optimization problems over one of these sets are thus nonconvex. We propose two methods for optimizing a real-valued function over the efficient...... and weakly efficient sets of an affine fractional vector optimization problem. The first method is a local one. By using a regularization function, we reformulate the problem into a standard smooth mathematical programming problem that allows applying available methods for smooth programming. In case...... the objective function is linear, we have investigated a global algorithm based upon a branch-and-bound procedure. The algorithm uses Lagrangian bound coupling with a simplicial bisection in the criteria space. Preliminary computational results show that the global algorithm is promising....

Methods of Efficient Study Habits and Physics Learning

Science.gov (United States)

Zettili, Nouredine

2010-02-01

We want to discuss the methods of efficient study habits and how they can be used by students to help them improve learning physics. In particular, we deal with the most efficient techniques needed to help students improve their study skills. We focus on topics such as the skills of how to develop long term memory, how to improve concentration power, how to take class notes, how to prepare for and take exams, how to study scientific subjects such as physics. We argue that the students who conscientiously use the methods of efficient study habits achieve higher results than those students who do not; moreover, a student equipped with the proper study skills will spend much less time to learn a subject than a student who has no good study habits. The underlying issue here is not the quantity of time allocated to the study efforts by the students, but the efficiency and quality of actions so that the student can function at peak efficiency. These ideas were developed as part of Project IMPACTSEED (IMproving Physics And Chemistry Teaching in SEcondary Education), an outreach grant funded by the Alabama Commission on Higher Education. This project is motivated by a major pressing local need: A large number of high school physics teachers teach out of field. )

Effects of landforms on the erosion rate in a small watershed by the {sup 137}Cs tracing method

Energy Technology Data Exchange (ETDEWEB)

Li Mian, E-mail: hnli-mian@163.co [Yellow River Institute of Hydraulic Research, Key Laboratory of Sediment Research of Yellow River of Ministry of Water Resources, Zhengzhou, Henan 450003 (China); Yao Wenyi [Yellow River Institute of Hydraulic Research, Key Laboratory of Sediment Research of Yellow River of Ministry of Water Resources, Zhengzhou, Henan 450003 (China); Li Zhanbin [Xi' an University of Technology, Xi' an, Shaanxi 710048 (China); Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shaanxi 712100 (China); Liu Puling [Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shaanxi 712100 (China); Shen Zhenzhou [Yellow River Institute of Hydraulic Research, Key Laboratory of Sediment Research of Yellow River of Ministry of Water Resources, Zhengzhou, Henan 450003 (China)

2010-05-15

It's very important to analyze and evaluate quantitatively the effects of landforms on soil erosion for the prevention and treatment of soil loss in a small watershed. The objective of this study was to evaluate the effects of landform factors on erosion rate by the {sup 137}Cs tracing method in a small watershed in the Purple Hilly Area of China. The erosion rates under different slope lengths, slope gradients and slope aspects were estimated in Xiangshuitan watershed in the Purple Hilly Area in Sichuan Basin by the {sup 137}Cs tracing method. The results showed that the erosion rate decreased exponentially with downslope distance, and it increased with increasing slope gradient during the scope of 5 deg. - 16 deg. The slope aspect had great impact on the erosion rate, and the hillside on the sunny slope had larger erosion rate than that on the shady slope, particularly for the farmland.

NEXUS: tracing the cosmic web connection

Science.gov (United States)

Cautun, Marius; van de Weygaert, Rien; Jones, Bernard J. T.

2013-02-01

We introduce the NEXUS algorithm for the identification of cosmic web environments: clusters, filaments, walls and voids. This is a multiscale and automatic morphological analysis tool that identifies all the cosmic structures in a scale free way, without preference for a certain size or shape. We develop the NEXUS method to incorporate the density, tidal field, velocity divergence and velocity shear as tracers of the cosmic web. We also present the NEXUS+ procedure which, taking advantage of a novel filtering of the density in logarithmic space, is very successful at identifying the filament and wall environments in a robust and natural way. To assess the algorithms we apply them to an N-body simulation. We find that all methods correctly identify the most prominent filaments and walls, while there are differences in the detection of the more tenuous structures. In general, the structures traced by the density and tidal fields are clumpier and more rugged than those present in the velocity divergence and velocity shear fields. We find that the NEXUS+ method captures much better the filamentary and wall networks and is successful in detecting even the fainter structures. We also confirm the efficiency of our methods by examining the dark matter particle and halo distributions.

Liquid phase microextraction for the analysis of trace elements and their speciation

International Nuclear Information System (INIS)

Hu, Bin; He, Man; Chen, Beibei; Xia, Linbo

2013-01-01

Trace/ultra-trace elements and their speciation analysis in complex matrices usually require sample preparation procedures to achieve sample clean-up and analyte preconcentration. Sample preparation is often the bottleneck in trace elements and their speciation analysis which has a direct impact on accuracy, precision and limits of detection and is often the rate-determining step of the analytical process. Recent trends in sample preparation include miniaturization, automation, high-throughput performance and reduction in solvent/sample consumption and operation time. Liquid-phase microextraction (LPME) technique as a novel and promising alternative in sample preparation can meet these requirements and has become a very efficient sample preparation technique. This review updates the state of art of LPME for trace elements and their speciation analysis and discusses its promising prospects. The major thrust of the article highlights the applications of LPME including single-drop microextraction (SDME), hollow fiber-liquid phase microextraction (HF-LPME), dispersive liquid liquid microextraction (DLLME) and solidified floating organic drop microextraction (SFODME) to the fields of elemental and their speciation analysis by atomic spectrometry-based methods, especially inductively coupled plasma mass spectrometry. General and specific concepts, different extraction formats and characteristics of LPME are described and compared, along with examples of recent innovations and applications presented to demonstrate its potential for trace elements and their speciation analysis in biological and environmental fields. Moreover, the application potential and an outlook on the combination of LPME and atomic spectrometry-based techniques for inorganic analysis are commentated. - Highlights: • The state of art of LPME for trace elements and their speciation analysis is updated. • Different extraction formats of LPME are described. • The application potential and future

Trace elements in airborne particulates in South Africa

International Nuclear Information System (INIS)

Vleggaar, C.M.; Van As, D.; Watkins, J.L.; Mingay, D.W.; Wells, R.B.; Briggs, A.B.; Louw, C.W.

1980-10-01

Airborne particulate materials were monitored continously with calendar month sampling periods at 5 rural/background, 4 rural/developing/peri-urban, 6 urban and 7 industrial sites in South Africa. Concentrations of Al, Br, Ca, Cs, Cd, Cl, Co, Cr, Cu, Eu, Fe, K, Mg, Mn, Na, Ni, Pb, Rb, S, Sb, Sc, Se, Ti, V and Zn were determined with neutron activation analysis (NAA), atomic absorption spectroscopy (AAS) and particle-induced X-ray emission spectroscopy (PIXE) employed on a complementary basis. A review of sources of airborne trace elements is given. The monitoring program, sampling, sample-handling procedures, as well as the analytical methods used, are discussed in detail. The results of related studies, i.e. effects of filter materials; sampling rates and geometry; determinations of collection efficiencies; particle size ranges; effects of internal flux monitors on the precision and accuracy of NAA; trace impurities in blank materials; quality control by routine analysis of reference materials; comparison of results obtained by NAA, AAS, and PIXE analysis; are given, as is a review of air-pollution control and research policy in South Africa and of ambient air quality standards. Results are discussed in terms of general patterns in trace-element concentrations and enrichments, the general pattern in population centres, the variability of monthly concentrations, and in terms of long-term trends at background, rural, developing, peri-urban, urban and industrial sites. Cases of concern in respect of increasing concentrations are pointed out, as are the constantly high Pb levels at urban sites [af

Real time ray tracing based on shader

Science.gov (United States)

Gui, JiangHeng; Li, Min

2017-07-01

Ray tracing is a rendering algorithm for generating an image through tracing lights into an image plane, it can simulate complicate optical phenomenon like refraction, depth of field and motion blur. Compared with rasterization, ray tracing can achieve more realistic rendering result, however with greater computational cost, simple scene rendering can consume tons of time. With the GPU's performance improvement and the advent of programmable rendering pipeline, complicated algorithm can also be implemented directly on shader. So, this paper proposes a new method that implement ray tracing directly on fragment shader, mainly include: surface intersection, importance sampling and progressive rendering. With the help of GPU's powerful throughput capability, it can implement real time rendering of simple scene.

Efficient reconstruction of dispersive dielectric profiles using time domain reflectometry (TDR

Directory of Open Access Journals (Sweden)

P. Leidenberger

2006-01-01

Full Text Available We present a numerical model for time domain reflectometry (TDR signal propagation in dispersive dielectric materials. The numerical probe model is terminated with a parallel circuit, consisting of an ohmic resistor and an ideal capacitance. We derive analytical approximations for the capacitance, the inductance and the conductance of three-wire probes. We couple the time domain model with global optimization in order to reconstruct water content profiles from TDR traces. For efficiently solving the inverse problem we use genetic algorithms combined with a hierarchical parameterization. We investigate the performance of the method by reconstructing synthetically generated profiles. The algorithm is then applied to retrieve dielectric profiles from TDR traces measured in the field. We succeed in reconstructing dielectric and ohmic profiles where conventional methods, based on travel time extraction, fail.

Comparative evaluation of trace elements in blood

International Nuclear Information System (INIS)

Goeij, J.J.M. de; Tjioe, P.S.; Pries, C.; Zwiers, J.H.L.

1976-01-01

The Interuniversitair Reactor Instituut and the Centraal Laboratorium TNO have carried out a common investigation on neutron-activation-analytical procedures for the determination of trace elements in blood. A comparative evaluation of five methods, destructive as well as non-destructive, is given. The sensitivity and reproducibility of the procedures are discussed. By combining some of the methods it is possible, starting with 1 ml blood, to give quantitative information on 14 important trace elements: antimony, arsenic, bromine, cadmium, cobalt, gold, copper, mercury, molybdenum, nickel, rubidium, selenium, iron and zinc. The methods have also been applied to sodium, chromium and potassium

Freeze dried samples of volcanic gases - a new method for the determination of trace elements by NAA

International Nuclear Information System (INIS)

Bichler, M.; Sortino, F.

1997-01-01

A new routine technique for the determination of trace elements in volcanic gases by NAA is presented. For time and money saving reasons this method is applicable to samples, collected by the conventional method. This technique uses evacuated glass bottles, partly filled with NaOH solution to absorb acidic gas components and CO 2 , which is the main constituent of the incondensable gas fraction at ambient conditions. The application of NAA to samples collected by this method shows two main sources of difficulties: drying of NaOH without loosing volatile elements of interest (in particular Hg and Se) and the high activities of 24 Na after neutron irradiation. The first can be avoided by liquid irradiation, thereby limiting the irradiation time, the second excludes the determination of short and medium lived nuclides because of the high γ-background due to 24 Na. A new freeze drying technique enables the application of long irradiation times and therefore the use of long-lived activation products for analysis. The samples of volcanic gases were collected at the fumarole fields of La Fossa volcano on the island Vulcano. Southern Italy. This technique allows very sensitive determinations of trace elements in volcanic gases and adds highly valuable information to the understanding and modeling of volcanic gas sources. (orig.)

A new method of derived equatorial plasma bubbles motion by tracing OI 630 nm emission all-sky images

Science.gov (United States)

Li, M.; Yu, T.; Chunliang, X.; Zuo, X.; Liu, Z.

2017-12-01

A new method for estimating the equatorial plasma bubbles (EPBs) motions from airglow emission all-sky images is presented in this paper. This method, which is called 'cloud-derived wind technology' and widely used in satellite observation of wind, could reasonable derive zonal and meridional velocity vectors of EPBs drifts by tracking a series of successive airglow 630.0 nm emission images. Airglow emission images data are available from an all sky airglow camera in Hainan Fuke (19.5°N, 109.2°E) supported by China Meridional Project, which can receive the 630.0nm emission from the ionosphere F region at low-latitudes to observe plasma bubbles. A series of pretreatment technology, e.g. image enhancement, orientation correction, image projection are utilized to preprocess the raw observation. Then the regions of plasma bubble extracted from the images are divided into several small tracing windows and each tracing window can find a target window in the searching area in following image, which is considered as the position tracing window moved to. According to this, velocities in each window are calculated by using the technology of cloud-derived wind. When applying the cloud-derived wind technology, the maximum correlation coefficient (MCC) and the histogram of gradient (HOG) methods to find the target window, which mean to find the maximum correlation and the minimum euclidean distance between two gradient histograms in respectively, are investigated and compared in detail. The maximum correlation method is fianlly adopted in this study to analyze the velocity of plasma bubbles because of its better performance than HOG. All-sky images from Hainan Fuke, between August 2014 and October 2014, are analyzed to investigate the plasma bubble drift velocities using MCC method. The data at different local time at 9 nights are studied and find that zonal drift velocity in different latitude at different local time ranges from 50 m/s to 180 m/s and there is a peak value at

Tracing Asian Seabass Individuals to Single Fish Farms Using Microsatellites

Science.gov (United States)

Yue, Gen Hua; Xia, Jun Hong; Liu, Peng; Liu, Feng; Sun, Fei; Lin, Grace

2012-01-01

Traceability through physical labels is well established, but it is not highly reliable as physical labels can be easily changed or lost. Application of DNA markers to the traceability of food plays an increasingly important role for consumer protection and confidence building. In this study, we tested the efficiency of 16 polymorphic microsatellites and their combinations for tracing 368 fish to four populations where they originated. Using the maximum likelihood and Bayesian methods, three most efficient microsatellites were required to assign over 95% of fish to the correct populations. Selection of markers based on the assignment score estimated with the software WHICHLOCI was most effective in choosing markers for individual assignment, followed by the selection based on the allele number of individual markers. By combining rapid DNA extraction, and high-throughput genotyping of selected microsatellites, it is possible to conduct routine genetic traceability with high accuracy in Asian seabass. PMID:23285169

On the trace anomaly of a Weyl fermion

Energy Technology Data Exchange (ETDEWEB)

Bastianelli, Fiorenzo; Martelli, Riccardo [Dipartimento di Fisica e Astronomia, Università di Bologna,via Irnerio 46, I-40126 Bologna (Italy); INFN - Sezione di Bologna,via Irnerio 46, I-40126 Bologna (Italy)

2016-11-29

We calculate the trace anomaly of a Weyl fermion coupled to gravity by using Fujikawa’s method supplemented by a consistent regulator. The latter is constructed out of Pauli-Villars regulating fields. The motivation for presenting such a calculation stems from recent studies that suggest that the trace anomaly of chiral fermions in four dimensions might contain an imaginary part proportional to the Pontryagin density. We find that the trace anomaly of a Weyl fermion is given by half the trace anomaly of a Dirac fermion, so that no imaginary part proportional to the Pontryagin density is seen to arise.

A Computationally Efficient Method for Polyphonic Pitch Estimation

Directory of Open Access Journals (Sweden)

Ruohua Zhou

2009-01-01

Full Text Available This paper presents a computationally efficient method for polyphonic pitch estimation. The method employs the Fast Resonator Time-Frequency Image (RTFI as the basic time-frequency analysis tool. The approach is composed of two main stages. First, a preliminary pitch estimation is obtained by means of a simple peak-picking procedure in the pitch energy spectrum. Such spectrum is calculated from the original RTFI energy spectrum according to harmonic grouping principles. Then the incorrect estimations are removed according to spectral irregularity and knowledge of the harmonic structures of the music notes played on commonly used music instruments. The new approach is compared with a variety of other frame-based polyphonic pitch estimation methods, and results demonstrate the high performance and computational efficiency of the approach.

The validation of a method for determining the migration of trace elements from food packaging materials into food

International Nuclear Information System (INIS)

Thompson, D.; Parry, S.J.; Benzing, R.

1997-01-01

A new radiotracer method has been developed to measure the migration of trace elements from food contact packaging into four standard food simulants; acetic acid, ethanol, olive oil, deionised water. A sample of material is irradiated in a thermal neutron flux of 10 16 n x m -2 x s -1 to activate the trace elements and produce a range of radionuclides. The samples is then placed in the food simulant and the migration of the radionuclides is monitored by performing γ-ray spectrometry on a sample of the simulant. Any radionuclides measured must be due entirely to the migration of the elements present in the plastic, since the simulant itself is not radioactive. Preliminary studies have shown that detection limits of around 0.2 μg x dm -2 (0.002 mg/kg) can be achieved for antimony in a sample of polyethylene terephthalate. This method can now been extended to measure migration into real foods. This will highlight any differences between the standard simulants currently used and real foods. Since the method only involves irradiation of the packaging material any food matrix can be studied. (author)

Bulk derivatization and cation exchange restricted access media-based trap-and-elute liquid chromatography–mass spectrometry method for determination of trace estrogens in serum

International Nuclear Information System (INIS)

Beinhauer, Jana; Bian, Liangqiao; Fan, Hui; Šebela, Marek; Kukula, Maciej; Barrera, Jose A.

2015-01-01

Highlights: • Analysis of estrogens in small volume samples at low parts-per-trillion concentration. • Charged bulk derivatization facilitates on-line ion exchange sample preparation. • On-line WCX restricted access media traps analytes, but not proteins and lipids. • Complete preparation and LC–MS/MS analysis completed in 30 min/sample. - Abstract: Estrone (E1), estradiols (α/β-E2), and estriol (E3) are four major metabolically active estrogens exerting strong biological activities at very low circulating concentrations. This paper reports a sensitive and efficient method with automated, on-line clean-up and detection to determine trace estrogens in a small volume of serum samples using liquid chromatography–electrospray ionization–tandem mass spectrometry directly, without off-line liquid–liquid or solid-phase extraction pretreatments. Serum aliquots (charcoal stripped fetal bovine serum, 100 μL) were spiked with four estrogen standards and their corresponding isotope-labeled internal standards, then bulk derivatized with 2-fluoro-1-methyl-pyridium p-toluenesulfonate (2-FMP) to establish the calibration curves and perform method validation. Calibration was established in the concentration ranges of 5–1000 pg mL −1 , and demonstrated good linearity of R 2 from 0.9944 to 0.9997 for the four derivatized estrogens. The lower detection limits obtained were 3–7 pg mL −1 . Good accuracy and precision in the range of 86–112% and 2.3–11.9%, respectively, were observed for the quality control (QC) samples at low, medium, and high concentration levels. The stability tests showed that the derivatized serum samples were stable 8 h after derivatization at room temperature and at least to 48 h if stored at −20 °C. The method was applied to measure trace estrogens in real human and bovine serum samples, and three of four estrogen compounds studied were observed and quantified

Trace element measurements with synchrotron radiation

International Nuclear Information System (INIS)

Hanson, A.L.; Kraner, H.W.; Jones, K.W.; Gordon, B.M.; Mills, R.E.

1982-01-01

Aspects of the application of synchrotron radiation to trace element determinations by x-ray fluorescence have been investigated using beams from the Cornell facility, CHESS. Fluoresced x rays were detected with a Si(Li) detector placed 4 cm from the target at 90 0 to the beam. Thick samples of NBS Standard Reference Materials were used to calibrate trace element sensitivity and estimate minimum detectable limits for this method

Quantitative sampling and analysis of trace elements in atmospheric aerosols: impactor characterization and Synchrotron-XRF mass calibration

Directory of Open Access Journals (Sweden)

A. Richard

2010-10-01

Full Text Available Identification of trace elements in ambient air can add substantial information to pollution source apportionment studies, although they do not contribute significantly to emissions in terms of mass. A method for quantitative size and time-resolved trace element evaluation in ambient aerosols with a rotating drum impactor and synchrotron radiation based X-ray fluorescence is presented. The impactor collection efficiency curves and size segregation characteristics were investigated in an experiment with oil and salt particles. Cutoff diameters were determined through the ratio of size distributions measured with two particle sizers. Furthermore, an external calibration technique to empirically link fluorescence intensities to ambient concentrations was developed. Solutions of elemental standards were applied with an ink-jet printer on thin films and area concentrations were subsequently evaluated with external wet chemical methods. These customized and reusable reference standards enable quantification of different data sets analyzed under varying experimental conditions.

Ultrasensitive microchip based on smart microgel for real-time online detection of trace threat analytes.

Science.gov (United States)

Lin, Shuo; Wang, Wei; Ju, Xiao-Jie; Xie, Rui; Liu, Zhuang; Yu, Hai-Rong; Zhang, Chuan; Chu, Liang-Yin

2016-02-23

Real-time online detection of trace threat analytes is critical for global sustainability, whereas the key challenge is how to efficiently convert and amplify analyte signals into simple readouts. Here we report an ultrasensitive microfluidic platform incorporated with smart microgel for real-time online detection of trace threat analytes. The microgel can swell responding to specific stimulus in flowing solution, resulting in efficient conversion of the stimulus signal into significantly amplified signal of flow-rate change; thus highly sensitive, fast, and selective detection can be achieved. We demonstrate this by incorporating ion-recognizable microgel for detecting trace Pb(2+), and connecting our platform with pipelines of tap water and wastewater for real-time online Pb(2+) detection to achieve timely pollution warning and terminating. This work provides a generalizable platform for incorporating myriad stimuli-responsive microgels to achieve ever-better performance for real-time online detection of various trace threat molecules, and may expand the scope of applications of detection techniques.

Photometric determination of traces of metals

International Nuclear Information System (INIS)

Onishi, H.

1986-01-01

The first three editions of this widely used classic were published under the title Colorimetric Determination of Traces of Metals, with E.B. Sandell as author. Part I (General Aspects) of the fourth edition was co-authored by E.B. Sandell and H. Onishi and published in 1978. After Sandell's death in 1984, Onishi assumed the monumental task of revising Part II. This book (Part IIA) consists of 21 chapters in which the photometric determinations of the individual metals, aluminium to lithium (including the lanthanoids), are described. Each chapter is divided into three sections: Separations, Methods of Determination, and Applications. The sections on Separations are of general interest and include methods based on precipitation, ion-exchange, chromatography, and liquid-liquid extraction. Molecular absorption and fluorescence techniques are described in the sections on determinations, and the emphasis is on the use of well-established reagents. Several reagents that have been recently introduced for the determination of trace levels of metals are also critically reviewed at the end of each section on methods of determination. Important applications of these methods to the determination of trace metals in complex organic and inorganic materials are described in detail at the end of each chapter

Efficient forced vibration reanalysis method for rotating electric machines

Science.gov (United States)

Saito, Akira; Suzuki, Hiromitsu; Kuroishi, Masakatsu; Nakai, Hideo

2015-01-01

Rotating electric machines are subject to forced vibration by magnetic force excitation with wide-band frequency spectrum that are dependent on the operating conditions. Therefore, when designing the electric machines, it is inevitable to compute the vibration response of the machines at various operating conditions efficiently and accurately. This paper presents an efficient frequency-domain vibration analysis method for the electric machines. The method enables the efficient re-analysis of the vibration response of electric machines at various operating conditions without the necessity to re-compute the harmonic response by finite element analyses. Theoretical background of the proposed method is provided, which is based on the modal reduction of the magnetic force excitation by a set of amplitude-modulated standing-waves. The method is applied to the forced response vibration of the interior permanent magnet motor at a fixed operating condition. The results computed by the proposed method agree very well with those computed by the conventional harmonic response analysis by the FEA. The proposed method is then applied to the spin-up test condition to demonstrate its applicability to various operating conditions. It is observed that the proposed method can successfully be applied to the spin-up test conditions, and the measured dominant frequency peaks in the frequency response can be well captured by the proposed approach.

Developments in the ray-tracing code Zgoubi for 6-D multiturn tracking in FFAG rings

International Nuclear Information System (INIS)

Lemuet, F.; Meot, F.

2005-01-01

A geometrical method for 3-D modeling of the magnetic field in scaling and non-scaling FFAG magnets has been installed in the ray-tracing code Zgoubi. The method in particular allows a good simulation of transverse non-linearities, of field fall-offs and possible merging fields in configurations of neighboring magnets, while using realistic models of magnetic fields. That yields an efficient tool for FFAG lattice design and optimizations, and for 6-D tracking studies. It is applied for illustration to the simulation of an acceleration cycle in a 150 MeV radial sector proton FFAG

An Efficient Method for Electron-Atom Scattering Using Ab-initio Calculations

Energy Technology Data Exchange (ETDEWEB)

Xu, Yuan; Yang, Yonggang; Xiao, Liantuan; Jia, Suotang [Shanxi University, Taiyuan (China)

2017-02-15

We present an efficient method based on ab-initio calculations to investigate electron-atom scatterings. Those calculations profit from methods implemented in standard quantum chemistry programs. The new approach is applied to electron-helium scattering. The results are compared with experimental and other theoretical references to demonstrate the efficiency of our method.

Method development for liquid chromatographic/triple quadrupole mass spectrometric analysis of trace level perfluorocarboxylic acids in articles of commerce

Science.gov (United States)

An analytical method to identify and quantify trace levels of C5 to C12 perfluorocarboxylic acids (PFCAs) in articles of commerce (AOC) is developed and rigorously validated. Solid samples were extracted in methanol, and liquid samples were diluted with a solvent consisting of 60...

The role of plant-associated bacteria in the mobilization and phytoextraction of trace elements in contaminated soils.

Science.gov (United States)

Sessitsch, Angela; Kuffner, Melanie; Kidd, Petra; Vangronsveld, Jaco; Wenzel, Walter W; Fallmann, Katharina; Puschenreiter, Markus

2013-05-01

Phytoextraction makes use of trace element-accumulating plants that concentrate the pollutants in their tissues. Pollutants can be then removed by harvesting plants. The success of phytoextraction depends on trace element availability to the roots and the ability of the plant to intercept, take up, and accumulate trace elements in shoots. Current phytoextraction practises either employ hyperaccumulators or fast-growing high biomass plants; the phytoextraction process may be enhanced by soil amendments that increase trace element availability in the soil. This review will focus on the role of plant-associated bacteria to enhance trace element availability in the rhizosphere. We report on the kind of bacteria typically found in association with trace element - tolerating or - accumulating plants and discuss how they can contribute to improve trace element uptake by plants and thus the efficiency and rate of phytoextraction. This enhanced trace element uptake can be attributed to a microbial modification of the absorptive properties of the roots such as increasing the root length and surface area and numbers of root hairs, or by increasing the plant availability of trace elements in the rhizosphere and the subsequent translocation to shoots via beneficial effects on plant growth, trace element complexation and alleviation of phytotoxicity. An analysis of data from literature shows that effects of bacterial inoculation on phytoextraction efficiency are currently inconsistent. Some key processes in plant-bacteria interactions and colonization by inoculated strains still need to be unravelled more in detail to allow full-scale application of bacteria assisted phytoremediation of trace element contaminated soils.

Toxic and trace elements in foodstuffs in Japan

International Nuclear Information System (INIS)

Muramatsu, Y.; Sumiya, M.; Ohmomo, Y.

1988-01-01

From the viewpoint of environmental safety assessment it is important to have information on the levels of toxic and trace elements in foodstuffs. It is also essential to develop suitable analytical methods for these elements in order to obtain accurate analytical data. In this paper, two analytical methods were used, inductively-coupled plasma atomic emission spectrometry (ICP-AES) and neutron activation analysis (NAA), for analysing toxic and trace elements in several food samples. 3 tabs

Topological Hochschild homology and the Bass trace conjecture

DEFF Research Database (Denmark)

Berrick, A. J.; Hesselholt, Lars

2015-01-01

We use the methods of topological Hochschild homology to shed new light on groups satisfying the Bass trace conjecture. Factorization of the Hattori–Stallings rank map through the Bökstedt–Hsiang–Madsen cyclotomic trace map leads to Linnell's restriction on such groups. As a new consequence...

Method for calculating annual energy efficiency improvement of TV sets

International Nuclear Information System (INIS)

Varman, M.; Mahlia, T.M.I.; Masjuki, H.H.

2006-01-01

The popularization of 24 h pay-TV, interactive video games, web-TV, VCD and DVD are poised to have a large impact on overall TV electricity consumption in the Malaysia. Following this increased consumption, energy efficiency standard present a highly effective measure for decreasing electricity consumption in the residential sector. The main problem in setting energy efficiency standard is identifying annual efficiency improvement, due to the lack of time series statistical data available in developing countries. This study attempts to present a method of calculating annual energy efficiency improvement for TV set, which can be used for implementing energy efficiency standard for TV sets in Malaysia and other developing countries. Although the presented result is only an approximation, definitely it is one of the ways of accomplishing energy standard. Furthermore, the method can be used for other appliances without any major modification

Method for calculating annual energy efficiency improvement of TV sets

Energy Technology Data Exchange (ETDEWEB)

Varman, M. [Department of Mechanical Engineering, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia); Mahlia, T.M.I. [Department of Mechanical Engineering, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia)]. E-mail: indra@um.edu.my; Masjuki, H.H. [Department of Mechanical Engineering, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia)

2006-10-15

The popularization of 24 h pay-TV, interactive video games, web-TV, VCD and DVD are poised to have a large impact on overall TV electricity consumption in the Malaysia. Following this increased consumption, energy efficiency standard present a highly effective measure for decreasing electricity consumption in the residential sector. The main problem in setting energy efficiency standard is identifying annual efficiency improvement, due to the lack of time series statistical data available in developing countries. This study attempts to present a method of calculating annual energy efficiency improvement for TV set, which can be used for implementing energy efficiency standard for TV sets in Malaysia and other developing countries. Although the presented result is only an approximation, definitely it is one of the ways of accomplishing energy standard. Furthermore, the method can be used for other appliances without any major modification.

Evaluation of Test Method for Solar Collector Efficiency

DEFF Research Database (Denmark)

Fan, Jianhua; Shah, Louise Jivan; Furbo, Simon

The test method of the standard EN12975-2 (European Committee for Standardization, 2004) is used by European test laboratories to determine the efficiency of solar collectors. In the test methods the mean solar collector fluid temperature in the solar collector, Tm is determined by the approximat...... and the sky temperature. Based on the investigations, recommendations for change of the test methods and test conditions are considered. The investigations are carried out within the NEGST (New Generation of Solar Thermal Systems) project financed by EU.......The test method of the standard EN12975-2 (European Committee for Standardization, 2004) is used by European test laboratories to determine the efficiency of solar collectors. In the test methods the mean solar collector fluid temperature in the solar collector, Tm is determined by the approximated...... equation where Tin is the inlet temperature to the collector and Tout is the outlet temperature from the collector. The specific heat of the solar collector fluid is in the test method as an approximation determined as a constant equal to the specific heat of the solar collector fluid at the temperature Tm...

77 FR 31756 - Energy Conservation Program: Alternative Efficiency Determination Methods and Alternative Rating...

Science.gov (United States)

2012-05-30

...-AC46 Energy Conservation Program: Alternative Efficiency Determination Methods and Alternative Rating... regulations authorizing the use of alternative methods of determining energy efficiency or energy consumption... alternative methods of determining energy efficiency or energy consumption of various consumer products and...

Partition/Ion-Exclusion Chromatographic Ion Stacking for the Analysis of Trace Anions in Water and Salt Samples by Ion Chromatography.

Science.gov (United States)

Akter, Fouzia; Saito, Shingo; Tasaki-Handa, Yuiko; Shibukawa, Masami

2018-01-01

A new analytical methodology for a simple and efficient on-line preconcentration of trace inorganic anions in water and salt samples prior to ion chromatographic determination is proposed. The preconcentration method is based on partition/ion-exclusion chromatographic ion stacking (PIEC ion stacking) with a hydrophilic polymer gel column containing a small amount of fixed anionic charges. The developed on-line PIEC ion stacking-ion chromatography method was validated by recovery experiments for the determination of nitrate in tap water in terms of both accuracy and precision, and the results showed the reliability of the method. The method proposed was also successfully applied to the determination of trace impurity nitrite and nitrate in reagent-grade salts of sodium sulfate. A low background level can be achieved since pure water is used as the eluant for the PIEC ion stacking. It is possible to reach sensitive detection at sub-μg L -1 levels by on-line PIEC ion stacking-ion chromatography.

Effects of cleaning methods upon preservation of stable isotopes and trace elements in shells of Cyprideis torosa (Crustacea, Ostracoda): Implications for palaeoenvironmental reconstruction

Science.gov (United States)

Roberts, L. R.; Holmes, J. A.; Leng, M. J.; Sloane, H. J.; Horne, D. J.

2018-06-01

The trace element (Sr/Ca and Mg/Ca) and stable isotope (δ18O and δ13C) geochemistry of fossil ostracod valves provide valuable information, particularly in lacustrine settings, on palaeo-water composition and palaeotemperature. The removal of sedimentary and organic contamination prior to geochemical analysis is essential to avoid bias of the results. Previous stable isotope and trace element work on ostracod shells has, however, employed different treatments for the removal of contamination beyond simple 'manual' cleaning using a paint brush and methanol under a low-power binocular microscope. For isotopic work pre-treatments include chemical oxidation, vacuum roasting and plasma ashing, and for trace element work sonication, chemical oxidation and reductive cleaning. The impact of different treatments on the geochemical composition of the valve calcite has not been evaluated in full, and a universal protocol has not been established. Here, a systematic investigation of the cleaning methods is undertaken using specimens of the ubiquitous euryhaline species, Cyprideis torosa. Cleaning methods are evaluated by undertaking paired analyses on a single carapace (comprising two valves); in modern ostracods, whose valves are assumed to be unaltered, the two valves should have identical geochemical and isotopic composition. Hence, when one valve is subjected to the chosen treatment and the other to simple manual cleaning any difference in composition can confidently be assigned to the treatment method. We show that certain cleaning methods have the potential to cause alteration to the geochemical signal, particularly Mg/Ca and δ18O, and hence have implications for palaeoenvironmental reconstructions. For trace-element determinations we recommend cleaning by sonication and for stable isotope analysis, oxidation by hydrogen peroxide. These methods remove contamination, yet do not significantly alter the geochemical signal.

Ray tracing method for simulation of laser beam interaction with random packings of powders

Science.gov (United States)

Kovalev, O. B.; Kovaleva, I. O.; Belyaev, V. V.

2018-03-01

Selective laser sintering is a technology of rapid manufacturing of a free form that is created as a solid object by selectively fusing successive layers of powder using a laser. The motivation of this study is due to the currently insufficient understanding of the processes and phenomena of selective laser melting of powders whose time scales differ by orders of magnitude. To construct random packings from mono- and polydispersed solid spheres, the algorithm of their generation based on the discrete element method is used. A numerical method of ray tracing is proposed that is used to simulate the interaction of laser radiation with a random bulk packing of spherical particles and to predict the optical properties of the granular layer, the extinction and absorption coefficients, depending on the optical properties of a powder material.

Biological optimization systems for enhancing photosynthetic efficiency and methods of use

Science.gov (United States)

Hunt, Ryan W.; Chinnasamy, Senthil; Das, Keshav C.; de Mattos, Erico Rolim

2012-11-06

Biological optimization systems for enhancing photosynthetic efficiency and methods of use. Specifically, methods for enhancing photosynthetic efficiency including applying pulsed light to a photosynthetic organism, using a chlorophyll fluorescence feedback control system to determine one or more photosynthetic efficiency parameters, and adjusting one or more of the photosynthetic efficiency parameters to drive the photosynthesis by the delivery of an amount of light to optimize light absorption of the photosynthetic organism while providing enough dark time between light pulses to prevent oversaturation of the chlorophyll reaction centers are disclosed.

Determination of trace gold in rocks and minerals by neutron activation analysis

International Nuclear Information System (INIS)

Zhao Yunlong; Zhou Suqing; Liang Yutang

1988-05-01

The determination of trace gold in rocks and minerals by neutron activation analysis is described. Two methods are used for pre-separating and concentrating the trace gold in geological samples. one of the methods is that the samples are dissolved in aqua regia solution; activated carbon paper pulp filter is used for pre-separating and concentrating trace gold by dynamic adsorption method; then the activated carbon containing gold was ashed at 650 ∼ 700 deg c. The other method is that the samples are dissolved in aqua regia solution; the polyurethane foam plastic filled with activated carbon is used for pre-separating and concentrating trace gold by dynamic adsorption method; then the foam plastic containing gold was ashed at 650 deg c. The gold in ashes is determinated by neutron activation analysis. The detection limit is 0.004ng/g. The accuracy of the method is examined by gold in reference standard material. The results of this method are in good agreement with the recommended value. For analysis of the trace gold by the methods of instrumental neutron activation analysis and epithermal neutron activation analysis, the interference of 411.8 keV γ-ray from 153 Sm, 152 Eu and fission products of uranium and the correction methods are discussed

Ionic liquid ultrasound assisted dispersive liquid-liquid microextraction method for preconcentration of trace amounts of rhodium prior to flame atomic absorption spectrometry determination

Energy Technology Data Exchange (ETDEWEB)

Molaakbari, Elaheh [Chemistry Department, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Young Research Society, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Mostafavi, Ali, E-mail: mostafavi.ali@gmail.com [Chemistry Department, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Afzali, Daryoush [Environment and Nanochemistry Department, Research Institute of Environmental Science, International Center for Science, High Technology and Environmental Science, Kerman (Iran, Islamic Republic of); Mineral Industries Research Center, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of)

2011-01-30

In this article, we consider ionic liquid based ultrasound-assisted dispersive liquid-liquid microextraction of trace amounts of rhodium from aqueous samples and show that this is a fast and reliable sample pre-treatment for the determination of rhodium ions by flame atomic absorption spectrometry. The Rh(III) was transferred into its complex with 2-(5-bromo-2-pyridylazo)-5-diethylamino phenol as a chelating agent, and an ultrasonic bath with the ionic liquid, 1-octyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide at room temperature was used to extract the analyte. The centrifuged rhodium complex was then enriched in the form of ionic liquid droplets and prior to its analysis by flame atomic absorption spectrometry, 300 {mu}L ethanol was added to the ionic liquid-rich phase. Finally, the influence of various parameters on the recovery of Rh(III) was optimized. Under optimum conditions, the calibration graph was linear in the range of 4.0-500.0 ng mL{sup -1}, the detection limit was 0.37 ng mL{sup -1} (3S{sub b}/m, n = 7) and the relative standard deviation was {+-}1.63% (n = 7, C = 200 ng mL{sup -1}). The results show that ionic liquid based ultrasound assisted dispersive liquid-liquid microextraction, combined with flame atomic absorption spectrometry, is a rapid, simple, sensitive and efficient analytical method for the separation and determination of trace amounts of Rh(III) ions with minimum organic solvent consumption.

Efficient decomposition and linearization methods for the stochastic transportation problem

International Nuclear Information System (INIS)

Holmberg, K.

1993-01-01

The stochastic transportation problem can be formulated as a convex transportation problem with nonlinear objective function and linear constraints. We compare several different methods based on decomposition techniques and linearization techniques for this problem, trying to find the most efficient method or combination of methods. We discuss and test a separable programming approach, the Frank-Wolfe method with and without modifications, the new technique of mean value cross decomposition and the more well known Lagrangian relaxation with subgradient optimization, as well as combinations of these approaches. Computational tests are presented, indicating that some new combination methods are quite efficient for large scale problems. (authors) (27 refs.)

Ar-39 Detection at the 10^-16 Isotopic Abundance Level with Atom Trap Trace Analysis

OpenAIRE

Jiang, W.; Williams, W. D.; Bailey, K.; Davis, A. M.; Hu, S. -M.; Lu, Z. -T.; O'Connor, T. P.; Purtschert, R.; Sturchio, N. C.; Sun, Y. R.; Mueller, P.

2011-01-01

Atom Trap Trace Analysis (ATTA), a laser-based atom counting method, has been applied to analyze atmospheric Ar-39 (half-life = 269 yr), a cosmogenic isotope with an isotopic abundance of 8x10^-16. In addition to the superior selectivity demonstrated in this work, counting rate and efficiency of ATTA have been improved by two orders of magnitude over prior results. Significant applications of this new analytical capability lie in radioisotope dating of ice and water samples and in the develop...

Opo lidar sounding of trace atmospheric gases in the 3 – 4 μm spectral range

Directory of Open Access Journals (Sweden)

Romanovskii Oleg A.

2018-01-01

Full Text Available The applicability of a KTA crystal-based laser system with optical parametric oscillators (OPO generation to lidar sounding of the atmosphere in the spectral range 3–4 μm is studied in this work. A technique developed for lidar sounding of trace atmospheric gases (TAG is based on differential absorption lidar (DIAL method and differential optical absorption spectroscopy (DOAS. The DIAL-DOAS technique is tested to estimate its efficiency for lidar sounding of atmospheric trace gases. The numerical simulation performed shows that a KTA-based OPO laser is a promising source of radiation for remote DIAL-DOAS sounding of the TAGs under study along surface tropospheric paths. A possibility of using a PD38-03-PR photodiode for the DIAL gas analysis of the atmosphere is shown.

Tracing Geothermal Fluids

Energy Technology Data Exchange (ETDEWEB)

Michael C. Adams; Greg Nash

2004-03-01

Geothermal water must be injected back into the reservoir after it has been used for power production. Injection is critical in maximizing the power production and lifetime of the reservoir. To use injectate effectively the direction and velocity of the injected water must be known or inferred. This information can be obtained by using chemical tracers to track the subsurface flow paths of the injected fluid. Tracers are chemical compounds that are added to the water as it is injected back into the reservoir. The hot production water is monitored for the presence of this tracer using the most sensitive analytic methods that are economically feasible. The amount and concentration pattern of the tracer revealed by this monitoring can be used to evaluate how effective the injection strategy is. However, the tracers must have properties that suite the environment that they will be used in. This requires careful consideration and testing of the tracer properties. In previous and parallel investigations we have developed tracers that are suitable from tracing liquid water. In this investigation, we developed tracers that can be used for steam and mixed water/steam environments. This work will improve the efficiency of injection management in geothermal fields, lowering the cost of energy production and increasing the power output of these systems.

Efficient Methods of Estimating Switchgrass Biomass Supplies

Science.gov (United States)

Switchgrass (Panicum virgatum L.) is being developed as a biofuel feedstock for the United States. Efficient and accurate methods to estimate switchgrass biomass feedstock supply within a production area will be required by biorefineries. Our main objective was to determine the effectiveness of in...

Trace analysis of U, Th and other heavy metals in high purity aluminium with isotope dilution mass spectrometry

International Nuclear Information System (INIS)

Beer, B.; Heumann, K.G.

1992-01-01

A method for the determination of very low concentrations of U, Th, Fe, Zn, Tl, Cd, Cu and Ag in high purity aluminium with isotope dilution mass spectrometry (IDMS) is developed using a compact and cost-efficient thermal ionization quadrupole mass spectrometer. The detection limits obtained are (in ng/g):U=0.018, Th=0.06, Fe=82, Zn=86, Tl=0.2, Cd=4, Cu=1, Ag=2.6. By this method it is possible to determine the α-emitters U and Th in aluminium down to the sub-ng/g level with good precision of 0.4-10% and 0.5-5%, respectively. The results should also be accurate because IDMS is a reliable analytical method. The dissolution of aluminium is carried out by aqua regia followed by the trace/matrix separation and the isolation of the trace elements by anion exchange chromatography (U, Th, Zn, Tl, Cd), electrodeposition (Cu, Ag) and extraction (Fe). Different aluminium samples are analysed by IDMS and the results are compared with those of other methods. (orig.)

Trace Dynamics and a non-commutative special relativity

International Nuclear Information System (INIS)

Lochan, Kinjalk; Singh, T.P.

2011-01-01

Trace Dynamics is a classical dynamical theory of non-commuting matrices in which cyclic permutation inside a trace is used to define the derivative with respect to an operator. We use the methods of Trace Dynamics to construct a non-commutative special relativity. We define a line-element using the Trace over space-time coordinates which are assumed to be operators. The line-element is shown to be invariant under standard Lorentz transformations, and is used to construct a non-commutative relativistic dynamics. The eventual motivation for constructing such a non-commutative relativity is to relate the statistical thermodynamics of this classical theory to quantum mechanics. -- Highlights: → Classical time is external to quantum mechanics. → This implies need for a formulation of quantum theory without classical time. → A starting point could be a non-commutative special relativity. → Such a relativity is developed here using the theory of Trace Dynamics. → A line-element is defined using the Trace over non-commuting space-time operators.

Interpretation of complexometric titration data: An intercomparison of methods for estimating models of trace metal complexation by natural organic ligands

NARCIS (Netherlands)

Pižeta, I.; Sander, S.G.; Hudson, R.J.M.; Omanovic, D.; Baars, O.; Barbeau, K.A.; Buck, K.N.; Bundy, R.M.; Carrasco, G.; Croot, P.L.; Garnier, C.; Gerringa, L.J.A.; Gledhill, M.; Hirose, K.; Kondo, Y.; Laglera, L.M.; Nuester, J.; Rijkenberg, M.J.A.; Takeda, S.; Twining, B.S.; Wells, M.

2015-01-01

With the common goal of more accurately and consistently quantifying ambient concentrations of free metal ions and natural organic ligands in aquatic ecosystems, researchers from 15 laboratories that routinely analyze trace metal speciation participated in an intercomparison of statistical methods

Multielement determination of trace metals in river water (certified reference material, JSAC 0301-1) by high efficiency nebulization ICP-MS after 100-fold preconcentration with a chelating resin-packed minicolumn

International Nuclear Information System (INIS)

Zhu, Yanbei; Hattori, Ryota; Fujimori, Eiji; Umemura, Tomonari; Haraguchi, Hiroki

2005-01-01

The determination of 34 trace metals in a river water certified reference material (CRM), i.e. JSAC 0301-1, which was issued by the Japan Society for Analytical Chemistry in January 2004, was performed by ICP-MS with a high efficiency nebulizer after preconcentration with a laboratory-made chelating resin-packed minicolumn, with which trace metals were concentrated 100-fold from 50 mL of a river water sample to 0.5 mL of the final analysis solution. Trace metals in JSAC 0301-1 were observed in the concentration range from 19 μg L -1 of Al to 0.000053 μg L -1 of Bi. It was found that most of the concentrations of trace metals, including rare earth elements (REEs), in JSAC 0301-1 were lower than those in JAC 0031, which was also a previously issued CRM prepared with water from the same river as that of JSAC 0301-1. The low concentrations of trace metals in JSAC 0301-1 might be attributed to the fact that there was heavy rain before collecting the original water sample to prepare the present CRM. Furthermore, the REE distribution patterns of JSAC 0301-1, JAC 0031 and the average values of river water samples in Japan were parallel to each other. These results indicate that the distributions of REEs in JSAC 0301-1 and JAC 0031 were the typical ones of river water samples in Japan. (author)

Technical Note: A direct ray-tracing method to compute integral depth dose in pencil beam proton radiography with a multilayer ionization chamber.

Science.gov (United States)

Farace, Paolo; Righetto, Roberto; Deffet, Sylvain; Meijers, Arturs; Vander Stappen, Francois

2016-12-01

To introduce a fast ray-tracing algorithm in pencil proton radiography (PR) with a multilayer ionization chamber (MLIC) for in vivo range error mapping. Pencil beam PR was obtained by delivering spots uniformly positioned in a square (45 × 45 mm 2 field-of-view) of 9 × 9 spots capable of crossing the phantoms (210 MeV). The exit beam was collected by a MLIC to sample the integral depth dose (IDD MLIC ). PRs of an electron-density and of a head phantom were acquired by moving the couch to obtain multiple 45 × 45 mm 2 frames. To map the corresponding range errors, the two-dimensional set of IDD MLIC was compared with (i) the integral depth dose computed by the treatment planning system (TPS) by both analytic (IDD TPS ) and Monte Carlo (IDD MC ) algorithms in a volume of water simulating the MLIC at the CT, and (ii) the integral depth dose directly computed by a simple ray-tracing algorithm (IDD direct ) through the same CT data. The exact spatial position of the spot pattern was numerically adjusted testing different in-plane positions and selecting the one that minimized the range differences between IDD direct and IDD MLIC . Range error mapping was feasible by both the TPS and the ray-tracing methods, but very sensitive to even small misalignments. In homogeneous regions, the range errors computed by the direct ray-tracing algorithm matched the results obtained by both the analytic and the Monte Carlo algorithms. In both phantoms, lateral heterogeneities were better modeled by the ray-tracing and the Monte Carlo algorithms than by the analytic TPS computation. Accordingly, when the pencil beam crossed lateral heterogeneities, the range errors mapped by the direct algorithm matched better the Monte Carlo maps than those obtained by the analytic algorithm. Finally, the simplicity of the ray-tracing algorithm allowed to implement a prototype procedure for automated spatial alignment. The ray-tracing algorithm can reliably replace the TPS method in MLIC PR for in

Study of trace metals in evaporites of Sergipe, Brazil

International Nuclear Information System (INIS)

Andrade, L.L.

1982-01-01

Heavy metals and others which form strong complexes must be present in the brine feed of electrolytic cells only at very low levels. Their occurrence in quantities above the established levels has a deleterious effect on the membranes of the cells and will produce interference on voltage, current efficiency and other factors. The waste resulting from decantation of the brine causes serious environmental problems. Thirty brine samples from different sites, provided by Petrobras Mineracao S.A. (Brazil) were studied. The sample preparation method and the analytical results obtained from semiquantitative determination of trace metals by optical emission spectrography are described. The toxicity of certain metals, their effects on the environment and on electrolytic cell membranes are also discussed. (Author) [pt

Tracing Asian seabass individuals to single fish farms using microsatellites.

Directory of Open Access Journals (Sweden)

Gen Hua Yue

Full Text Available Traceability through physical labels is well established, but it is not highly reliable as physical labels can be easily changed or lost. Application of DNA markers to the traceability of food plays an increasingly important role for consumer protection and confidence building. In this study, we tested the efficiency of 16 polymorphic microsatellites and their combinations for tracing 368 fish to four populations where they originated. Using the maximum likelihood and Bayesian methods, three most efficient microsatellites were required to assign over 95% of fish to the correct populations. Selection of markers based on the assignment score estimated with the software WHICHLOCI was most effective in choosing markers for individual assignment, followed by the selection based on the allele number of individual markers. By combining rapid DNA extraction, and high-throughput genotyping of selected microsatellites, it is possible to conduct routine genetic traceability with high accuracy in Asian seabass.

Modeling of Methods to Control Heat-Consumption Efficiency

Science.gov (United States)

Tsynaeva, E. A.; Tsynaeva, A. A.

2016-11-01

In this work, consideration has been given to thermophysical processes in automated heat consumption control systems (AHCCSs) of buildings, flow diagrams of these systems, and mathematical models describing the thermophysical processes during the systems' operation; an analysis of adequacy of the mathematical models has been presented. A comparison has been made of the operating efficiency of the systems and the methods to control the efficiency. It has been determined that the operating efficiency of an AHCCS depends on its diagram and the temperature chart of central quality control (CQC) and also on the temperature of a low-grade heat source for the system with a heat pump.

A method for speciation of trace elements (stable and radioactive) in natural waters

International Nuclear Information System (INIS)

Salbu, B.; Bjornstad, H.E.; Pappas, A.C.

1985-01-01

Radioactive nuclides and stable trace metals entering natural aquatic systems interact with naturally occurring particles through exchange and sorption processes. The extent of which depends not only on the elements and particles in question, but also on size distribution of particles being most pronounced for colloids having large surface areas to volume ratios. The interaction of radionuclides and trace metals with colloids changes their size and charge characteristics and thereby influences their transport, mobility and bioavailability

Resonant photoacoustic detection of NO2 traces with a Q-switched green laser

Science.gov (United States)

Slezak, Verónica; Codnia, Jorge; Peuriot, Alejandro L.; Santiago, Guillermo

2003-01-01

Resonant photoacoustic detection of NO2 traces by means of a high repetition pulsed green laser is presented. The resonator is a cylindrical Pyrex glass cell with a measured Q factor 380 for the first radial mode in air at atmospheric pressure. The system is calibrated with known mixtures in dry air and a minimum detectable volume concentration of 50 parts in 109 is obtained (S/N=1). Its sensitivity allows one to detect and quantify NO2 traces in the exhaust gases of cars. Previously, the analysis of gas adsorption and desorption on the walls and of changes in the sample composition is carried out in order to minimize errors in the determination of NO2 content upon application of the extractive method. The efficiency of catalytic converters of several models of automobiles is studied and the NO2 concentration in samples from exhausts of different types of engine (gasoline, diesel, and methane gas) at idling operation are measured.

Animate tracings in Michelangelo’s paper modani at San Lorenzo

DEFF Research Database (Denmark)

Foote, Jonathan

2016-01-01

exhibit no evidence of the use of compass or rule, a realization that has led scholars to conclude that he drew them free-hand. However, new observations reveal that his modani were constructed by means of a deliberate and highly ordered working method linked through cutting and tracing. Although...... Michelangelo did not rely on instruments of geometry or mathematics, manipulative tracing nevertheless generated a sequential order of guide marks, ticks, and smears. While tracing, he would freely shift, rotate, or flip the template, trace only part of it, or combine it with other sketches or tracings. Far...

Quantitative evaluation of ultrasonic wave propagation in inhomogeneous anisotropic austenitic welds using 3D ray tracing method. Numerical and experimental validation

International Nuclear Information System (INIS)

Kolkoori, Sanjeevareddy

2014-01-01

Austenitic welds and dissimilar welds are extensively used in primary circuit pipes and pressure vessels in nuclear power plants, chemical industries and fossil fuelled power plants because of their high fracture toughness, resistance to corrosion and creep at elevated temperatures. However, cracks may initiate in these weld materials during fabrication process or stress operations in service. Thus, it is very important to evaluate the structural integrity of these materials using highly reliable non-destructive testing (NDT) methods. Ultrasonic non-destructive inspection of austenitic welds and dissimilar weld components is complicated because of anisotropic columnar grain structure leading to beam splitting and beam deflection. Simulation tools play an important role in developing advanced reliable ultrasonic testing (UT) techniques and optimizing experimental parameters for inspection of austenitic welds and dissimilar weld components. The main aim of the thesis is to develop a 3D ray tracing model for quantitative evaluation of ultrasonic wave propagation in an inhomogeneous anisotropic austenitic weld material. Inhomogenity in the anisotropic weld material is represented by discretizing into several homogeneous layers. According to ray tracing model, ultrasonic ray paths are traced during its energy propagation through various discretized layers of the material and at each interface the problem of reflection and transmission is solved. The influence of anisotropy on ultrasonic reflection and transmission behaviour in an anisotropic austenitic weld material are quantitatively analyzed in three dimensions. The ultrasonic beam directivity in columnar grained austenitic steel material is determined three dimensionally using Lamb's reciprocity theorem. The developed ray tracing model evaluates the transducer excited ultrasonic fields accurately by taking into account the directivity of the transducer, divergence of the ray bundle, density of rays and phase

Quantitative evaluation of ultrasonic wave propagation in inhomogeneous anisotropic austenitic welds using 3D ray tracing method. Numerical and experimental validation

Energy Technology Data Exchange (ETDEWEB)

Kolkoori, Sanjeevareddy

2014-07-01

Austenitic welds and dissimilar welds are extensively used in primary circuit pipes and pressure vessels in nuclear power plants, chemical industries and fossil fuelled power plants because of their high fracture toughness, resistance to corrosion and creep at elevated temperatures. However, cracks may initiate in these weld materials during fabrication process or stress operations in service. Thus, it is very important to evaluate the structural integrity of these materials using highly reliable non-destructive testing (NDT) methods. Ultrasonic non-destructive inspection of austenitic welds and dissimilar weld components is complicated because of anisotropic columnar grain structure leading to beam splitting and beam deflection. Simulation tools play an important role in developing advanced reliable ultrasonic testing (UT) techniques and optimizing experimental parameters for inspection of austenitic welds and dissimilar weld components. The main aim of the thesis is to develop a 3D ray tracing model for quantitative evaluation of ultrasonic wave propagation in an inhomogeneous anisotropic austenitic weld material. Inhomogenity in the anisotropic weld material is represented by discretizing into several homogeneous layers. According to ray tracing model, ultrasonic ray paths are traced during its energy propagation through various discretized layers of the material and at each interface the problem of reflection and transmission is solved. The influence of anisotropy on ultrasonic reflection and transmission behaviour in an anisotropic austenitic weld material are quantitatively analyzed in three dimensions. The ultrasonic beam directivity in columnar grained austenitic steel material is determined three dimensionally using Lamb's reciprocity theorem. The developed ray tracing model evaluates the transducer excited ultrasonic fields accurately by taking into account the directivity of the transducer, divergence of the ray bundle, density of rays and phase

Scalar and configuration traces of operators in large spectroscopic spaces

International Nuclear Information System (INIS)

Chang, B.D.; Wong, S.S.M.

1978-01-01

In statistical spectroscopic calculations, the primary input is the trace of products of powers of Hamiltonian and excitation operators. The lack of a systematic approach to trace evaluation has been in the past one of the major difficulties in the applications of statistical spectroscopic methods. A general method with a simple derivation is described here to evaluate the scalar and configuration traces for operators expressed either in the m-scheme or fully coupled JT scheme. It is shown to be an effective method by actually programming it on a computer. Implications on the future applications of statistical spectroscopy in the area of level density, strength function and perturbation theory are also briefly discussed. (Auth.)

A study of the kinetics and the effect of trace elements on mixed anaerobic fermentative biogas production by ternary quadratic general rotary unitised design

International Nuclear Information System (INIS)

Zhang, Chenxiao; Lian, Jing; Jiang, Zongshan; Guo, Jianbo; Guo, Yankai; Gou, Chenye

2016-01-01

In this study the effect of trace elements on methanogenesis was investigated during mixed anaerobic fermentation using a single-factor experiment in the present study. The most effective concentrations of Fe"0, Fe"2"+, Co"2"+ and Ni"2"+ that were added were 1500, 250, 0.3 and 0.6 mg/L, respectively. The optimal trace element combination was 0.58 mg/L Ni"2"+, 1200 mg/L Fe"0 and 0.34 mg/L Co"2"+ by the ternary quadratic general rotary unitised design method. The degree of influence exerted by trace elements on the cumulative methane yields decreased in the order of Ni"2"+, Fe"0 and Co"2"+, and the maximum CH_4 yield was 241.6 mL/g volatile solids (VS), according to a regression equation. The non-dissolved organic carbon hydrolytic process showed a good fit with the first-order kinetic model. The maximum value of CH_4 was 312.87 mL/g VS. Compared to the control, the bioconversion efficiencies of CH_4 and CO_2 production increased by 36.76% and 74.50%, respectively, at the optimal trace element combination. The obtained results provide new knowledge for improvements in the efficiency of anaerobic fermentation biogas production

An Evaluation of the Efficiency of Different Hygienisation Methods

Science.gov (United States)

Zrubková, M.

2017-10-01

The aim of this study is to evaluate the efficiency of hygienisation by pasteurisation, temperature-phased anaerobic digestion and sludge liming. A summary of the legislation concerning sludge treatment, disposal and recycling is included. The hygienisation methods are compared not only in terms of hygienisation efficiency but a comparison of other criteria is also included.

Probing Trace-elements in Bitumen by Neutron Activation Analysis

NARCIS (Netherlands)

Nahar, S.N.; Schmets, A.J.M.; Scarpas, Athanasios

Trace elements and their concentrations play an important role in both chemical and physical properties of bitumen. Instrumental Neutron Activation Analysis (INAA) has been applied to determine the concentration of trace elements in bitumen. This method requires irradiation of the material with

TraceContract

Science.gov (United States)

Kavelund, Klaus; Barringer, Howard

2012-01-01

TraceContract is an API (Application Programming Interface) for trace analysis. A trace is a sequence of events, and can, for example, be generated by a running program, instrumented appropriately to generate events. An event can be any data object. An example of a trace is a log file containing events that a programmer has found important to record during a program execution. Trace - Contract takes as input such a trace together with a specification formulated using the API and reports on any violations of the specification, potentially calling code (reactions) to be executed when violations are detected. The software is developed as an internal DSL (Domain Specific Language) in the Scala programming language. Scala is a relatively new programming language that is specifically convenient for defining such internal DSLs due to a number of language characteristics. This includes Scala s elegant combination of object-oriented and functional programming, a succinct notation, and an advanced type system. The DSL offers a combination of data-parameterized state machines and temporal logic, which is novel. As an extension of Scala, it is a very expressive and convenient log file analysis framework.

Method for determining efficiency in a liquid scintillation system

International Nuclear Information System (INIS)

Laney, B.H.

1975-01-01

In a liquid scintillation system utilizing plural photomultiplyier means, a method for determining efficiency of coincident pulse detection. Various incremental counting efficiency levels are associated with asymptotic functions in a two dimension matrix in which the abscissa and ordinate correspond to the pulse heights of each of a pair of coincident pulses from different photomultiplier means. An efficiency determining point is located in the matrix based on the sum of the pulse heights of each of the coincident pulses as well as on the amplitude of the smallest pulse of the coincident pulses. The single counting efficiency determining point is recorded as the level of efficiency at which the photomultiplier means detect scintillations that generate coincident pulses having pulse heights equal to those recorded. (Patent Office Record)

INAA Application for Trace Element Determination in Biological Reference Material

Science.gov (United States)

Atmodjo, D. P. D.; Kurniawati, S.; Lestiani, D. D.; Adventini, N.

2017-06-01

Trace element determination in biological samples is often used in the study of health and toxicology. Determination change to its essentiality and toxicity of trace element require an accurate determination method, which implies that a good Quality Control (QC) procedure should be performed. In this study, QC for trace element determination in biological samples was applied by analyzing the Standard Reference Material (SRM) Bovine muscle 8414 NIST using Instrumental Neutron Activation Analysis (INAA). Three selected trace element such as Fe, Zn, and Se were determined. Accuracy of the elements showed as %recovery and precision as %coefficient of variance (%CV). The result showed that %recovery of Fe, Zn, and Se were in the range between 99.4-107%, 92.7-103%, and 91.9-112%, respectively, whereas %CV were 2.92, 3.70, and 5.37%, respectively. These results showed that INAA method is precise and accurate for trace element determination in biological matrices.

Paper based Flexible and Conformal SERS Substrate for Rapid Trace Detection on Real-world Surfaces

Science.gov (United States)

Singamaneni, Srikanth; Lee, Chang; Tian, Limei

2011-03-01

One of the important but often overlooked considerations in the design of surface enhanced Raman scattering (SERS) substrates for trace detection is the efficiency of sample collection. Conventional designs based on rigid substrates such as silicon, alumina, and glass resist conformal contact with the surface under investigation, making the sample collection inefficient. We demonstrate a novel SERS substrate based on common filter paper adsorbed with gold nanorods, which allows conformal contact with real-world surfaces, thus dramatically enhancing the sample collection efficiency compared to conventional rigid substrates. We demonstrate the detection of trace amounts of analyte (140 pg spread over 4 cm2) by simply swabbing the surface under investigation with the novel SERS substrate. The hierarchical fibrous structure of paper serves as a 3D vasculature for easy uptake and transport of the analytes to the electromagnetic hot spots in the paper. Simple yet highly efficient and cost effective SERS substrate demonstrated here brings SERS based trace detection closer to real-world applications. We acknowledge the financial support from Center for Materials Innovation at Washington University.

An efficient multilevel optimization method for engineering design

Science.gov (United States)

Vanderplaats, G. N.; Yang, Y. J.; Kim, D. S.

1988-01-01

An efficient multilevel deisgn optimization technique is presented. The proposed method is based on the concept of providing linearized information between the system level and subsystem level optimization tasks. The advantages of the method are that it does not require optimum sensitivities, nonlinear equality constraints are not needed, and the method is relatively easy to use. The disadvantage is that the coupling between subsystems is not dealt with in a precise mathematical manner.

Trace and ultratrace analysis methods for the determination of phosphorus by flow-injection techniques.

Science.gov (United States)

Motomizu, Shoji; Li, Zhen-Hai

2005-04-15

Trace (phosphorus determination by flow-injection analysis are reviewed. Most of the methods cited in this review are fundamentally based on the reaction of orthophosphate with molybdate to form heteropoly acids, such as molybdenum yellow and molybdenum blue, and some of the methods are based on the formation of such secondary reactions as ion associates and their aggregates with bulky cations, such as cationic dyes and quaternary ammonium ions. The heteropoly acids themselves can be measured by spectrophotometry, and the ion associate formed with a cationic dye, Malachite Green (MG), can be measured based on the coloration of MG. Light scattering detection methods can be used for measuring the aggregates of ion associates formed with bulky cations. Highly sensitive detection of phosphorus can be accomplished by fluorophotometry; Rhodamine B (RB) and its analogues react with molybdophosphate to form ion associates, which shows fluorescence quenching of RB: LOD is about 5 nM. The detection method based on the chemiluminescence of luminal oxidized with molybdophosphoric acids is probably the most sensitive of all the detection methods reported so far: LOD of the method is as low as 1nM. The LOD of the molybdenum blue method can be improved by using a liquid core waveguide: LOD is 0.5 nM.

A trace display and editing program for data from fluorescence based sequencing machines.

Science.gov (United States)

Gleeson, T; Hillier, L

1991-12-11

'Ted' (Trace editor) is a graphical editor for sequence and trace data from automated fluorescence sequencing machines. It provides facilities for viewing sequence and trace data (in top or bottom strand orientation), for editing the base sequence, for automated or manual trimming of the head (vector) and tail (uncertain data) from the sequence, for vertical and horizontal trace scaling, for keeping a history of sequence editing, and for output of the edited sequence. Ted has been used extensively in the C.elegans genome sequencing project, both as a stand-alone program and integrated into the Staden sequence assembly package, and has greatly aided in the efficiency and accuracy of sequence editing. It runs in the X windows environment on Sun workstations and is available from the authors. Ted currently supports sequence and trace data from the ABI 373A and Pharmacia A.L.F. sequencers.

Automatic Detect and Trace of Solar Filaments

Science.gov (United States)

Fang, Cheng; Chen, P. F.; Tang, Yu-hua; Hao, Qi; Guo, Yang

We developed a series of methods to automatically detect and trace solar filaments in solar Hα images. The programs are able to not only recognize filaments and determine their properties, such as the position, the area and other relevant parameters, but also to trace the daily evolution of the filaments. For solar full disk Hα images, the method consists of three parts: first, preprocessing is applied to correct the original images; second, the Canny edge-detection method is used to detect the filaments; third, filament properties are recognized through the morphological operators. For each Hα filament and its barb features, we introduced the unweighted undirected graph concept and adopted Dijkstra shortest-path algorithm to recognize the filament spine; then, using polarity inversion line shift method for measuring the polarities in both sides of the filament to determine the filament axis chirality; finally, employing connected components labeling method to identify the barbs and calculating the angle between each barb and spine to indicate the barb chirality. Our algorithms are applied to the observations from varied observatories, including the Optical & Near Infrared Solar Eruption Tracer (ONSET) in Nanjing University, Mauna Loa Solar Observatory (MLSO) and Big Bear Solar Observatory (BBSO). The programs are demonstrated to be effective and efficient. We used our method to automatically process and analyze 3470 images obtained by MLSO from January 1998 to December 2009, and a butterfly diagram of filaments is obtained. It shows that the latitudinal migration of solar filaments has three trends in the Solar Cycle 23: The drift velocity was fast from 1998 to the solar maximum; after the solar maximum, it became relatively slow and after 2006, the migration became divergent, signifying the solar minimum. About 60% filaments with the latitudes larger than 50 degree migrate towards the Polar Regions with relatively high velocities, and the latitudinal migrating

Efficiency Optimization Methods in Low-Power High-Frequency Digitally Controlled SMPS

Directory of Open Access Journals (Sweden)

Aleksandar Prodić

2010-06-01

Full Text Available This paper gives a review of several power efficiency optimization techniques that are utilizing advantages of emerging digital control in high frequency switch-mode power supplies (SMPS, processing power from a fraction of watt to several hundreds of watts. Loss mechanisms in semiconductor components are briefly reviewed and the related principles of online efficiency optimization through power stage segmentation and gate voltage variation presented. Practical implementations of such methods utilizing load prediction or data extraction from a digital control loop are shown. The benefits of the presented efficiency methods are verified through experimental results, showing efficiency improvements, ranging from 2% to 30%,depending on the load conditions.

An Efficient Parallel Multi-Scale Segmentation Method for Remote Sensing Imagery

Directory of Open Access Journals (Sweden)

Haiyan Gu

2018-04-01

Full Text Available Remote sensing (RS image segmentation is an essential step in geographic object-based image analysis (GEOBIA to ultimately derive “meaningful objects”. While many segmentation methods exist, most of them are not efficient for large data sets. Thus, the goal of this research is to develop an efficient parallel multi-scale segmentation method for RS imagery by combining graph theory and the fractal net evolution approach (FNEA. Specifically, a minimum spanning tree (MST algorithm in graph theory is proposed to be combined with a minimum heterogeneity rule (MHR algorithm that is used in FNEA. The MST algorithm is used for the initial segmentation while the MHR algorithm is used for object merging. An efficient implementation of the segmentation strategy is presented using data partition and the “reverse searching-forward processing” chain based on message passing interface (MPI parallel technology. Segmentation results of the proposed method using images from multiple sensors (airborne, SPECIM AISA EAGLE II, WorldView-2, RADARSAT-2 and different selected landscapes (residential/industrial, residential/agriculture covering four test sites indicated its efficiency in accuracy and speed. We conclude that the proposed method is applicable and efficient for the segmentation of a variety of RS imagery (airborne optical, satellite optical, SAR, high-spectral, while the accuracy is comparable with that of the FNEA method.

From trace chemistry to single atom chemistry

International Nuclear Information System (INIS)

Adloff, J.P.

1993-01-01

Hot atom chemistry in the vast majority of experimental works deals with the trace amount of radioactive matters. Accordingly, the concept of trace chemistry is at the heart of hot atom chemistry. Some aspects of the chemistry at trace scale and at subtrace scale are presented together with the related problems of speciation and the complication which may arise due to the formation of radio colloids. The examples of 127 I(n,γ) 128 I and 132 Te (β - ) 132 I are shown, and the method based on radioactivity was used. The procedure of separating the elements in pitchblende is shown as the example of the chemistry of traces. 13 27 Al+ 2 4 He→ 0 1 n+ 15 30 P and 15 30 P→ 14 30 Si+e + +V are shown, and how to recognize the presence of radioactive colloids is explained. The formation of radiocolloids is by the sorption of a trace radioelement on pre-existing colloidal impurity or the self-condensation of monomeric species. The temporal parameters of the nature of reactions at trace concentration are listed. The examples of Class A and Class B reactions are shown. The kinetics of reactions at trace level, radon concentration, anthropogenic Pu and natural Pu in environment, the behavior of Pu atoms and so on are described. (K.I.)

The efficiency of different estimation methods of hydro-physical limits

Directory of Open Access Journals (Sweden)

Emma María Martínez

2012-12-01

Full Text Available The soil water available to crops is defined by specific values of water potential limits. Underlying the estimation of hydro-physical limits, identified as permanent wilting point (PWP and field capacity (FC, is the selection of a suitable method based on a multi-criteria analysis that is not always clear and defined. In this kind of analysis, the time required for measurements must be taken into consideration as well as other external measurement factors, e.g., the reliability and suitability of the study area, measurement uncertainty, cost, effort and labour invested. In this paper, the efficiency of different methods for determining hydro-physical limits is evaluated by using indices that allow for the calculation of efficiency in terms of effort and cost. The analysis evaluates both direct determination methods (pressure plate - PP and water activity meter - WAM and indirect estimation methods (pedotransfer functions - PTFs. The PTFs must be validated for the area of interest before use, but the time and cost associated with this validation are not included in the cost of analysis. Compared to the other methods, the combined use of PP and WAM to determine hydro-physical limits differs significantly in time and cost required and quality of information. For direct methods, increasing sample size significantly reduces cost and time. This paper assesses the effectiveness of combining a general analysis based on efficiency indices and more specific analyses based on the different influencing factors, which were considered separately so as not to mask potential benefits or drawbacks that are not evidenced in efficiency estimation.

Application of an efficient Bayesian discretization method to biomedical data

Directory of Open Access Journals (Sweden)

Gopalakrishnan Vanathi

2011-07-01

Full Text Available Abstract Background Several data mining methods require data that are discrete, and other methods often perform better with discrete data. We introduce an efficient Bayesian discretization (EBD method for optimal discretization of variables that runs efficiently on high-dimensional biomedical datasets. The EBD method consists of two components, namely, a Bayesian score to evaluate discretizations and a dynamic programming search procedure to efficiently search the space of possible discretizations. We compared the performance of EBD to Fayyad and Irani's (FI discretization method, which is commonly used for discretization. Results On 24 biomedical datasets obtained from high-throughput transcriptomic and proteomic studies, the classification performances of the C4.5 classifier and the naïve Bayes classifier were statistically significantly better when the predictor variables were discretized using EBD over FI. EBD was statistically significantly more stable to the variability of the datasets than FI. However, EBD was less robust, though not statistically significantly so, than FI and produced slightly more complex discretizations than FI. Conclusions On a range of biomedical datasets, a Bayesian discretization method (EBD yielded better classification performance and stability but was less robust than the widely used FI discretization method. The EBD discretization method is easy to implement, permits the incorporation of prior knowledge and belief, and is sufficiently fast for application to high-dimensional data.

Some Chemical Group Separations of Radioactive Trace Elements

Energy Technology Data Exchange (ETDEWEB)

Samsahl, K

1962-06-15

As a pretreatment for gamma spectrometric analysis methods have been developed for the chemical separation of traces of P, Sc, Ge, As, Se, Br, Zr, Nb, Ru, Ag, Cd, Sn, Sb, I, Hf, Ta, Re, Os, Au and Hg into 9 different groups. By combining the present methods with already existing chemical group separation methods for traces of Na, K, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Rb, Sr, Mo, In, Fe, Cs, Ba, L.a, the rare earths, W and Ir, a complete separation scheme comprising 15 groups of elements has been worked out. The chemical 15-group separation method has been advantageously used in gamma spectrometric routine analysis of biological materials.

Some Chemical Group Separations of Radioactive Trace Elements

International Nuclear Information System (INIS)

Samsahl, K.

1962-06-01

As a pretreatment for gamma spectrometric analysis methods have been developed for the chemical separation of traces of P, Sc, Ge, As, Se, Br, Zr, Nb, Ru, Ag, Cd, Sn, Sb, I, Hf, Ta, Re, Os, Au and Hg into 9 different groups. By combining the present methods with already existing chemical group separation methods for traces of Na, K, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Rb, Sr, Mo, In, Fe, Cs, Ba, L.a, the rare earths, W and Ir, a complete separation scheme comprising 15 groups of elements has been worked out. The chemical 15-group separation method has been advantageously used in gamma spectrometric routine analysis of biological materials

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

Preconcentration of trace elements

International Nuclear Information System (INIS)

Zolotov, Yu. A.; Kuz'min, N.M.

1990-01-01

This monograph deals with the theory and practical applications of trace metals preconcentration. It gives general characteristics of the process and describes in detail the methods of preconcentration: solvent extraction, sorption, co-precipitation, volatilization, and others. Special attention is given to preconcentration in combination with subsequent determination methods. The use of preconcentration in analysis of environmental and biological samples, mineral raw materials, high purity substances, and various industrial materials is also considered

Analysis of trace elements in human hair by PIXE

International Nuclear Information System (INIS)

Baptista, G.B.; Montenegro, E.C.; Paschoa, A.S.; Barros Leite, C.V. de.

1980-10-01

The PIXE method was applied to the analysis of trace elements in scalp hair using two methods for target preparation. In the first method eigth hair strands each with nearly cylindrical geommetry and approximately the same diameter were selected and placed on an aluminum frame. In the second method a given mass of hair was dissolved with nitric acid and a known amount of strontium was added to the solution and dripped on a membrane filter using a micropipet. The results for the concentrations of trace elements in hair obtained by the two methods are compared and several aspects of the analysis is discussed. (Author) [pt

The reliability of head film measurements. 3. Tracing superimposition.

Science.gov (United States)

Baumrind, S; Miller, D; Molthen, R

1976-12-01

The superimposition of tracings from lateral skull x-ray films taken at different timepoints is an important method for assessing developmental and treatment changes through time. The usefulness of the data derived is, however, limited by the fact that the physical act of superimposing tracings is performed with some error. The magnitudes of error for superimpositions on different "planes" have not been amenable to quantitation by previously available methods. Using newly developed computer-aided techniques, we have been able to quantitate both the primary errors of tracing superimposition and the associated secondary landmark displacements for four conventionally employed anatomic reference "planes". For each reference "plane," twenty-five independent film pairs were examined independently by each of four judges. Therefore, 100 acts of tracing superimposition were available for each reference "plane." Output data are presented which appear to support the conclusion that measurement errors in tracing superimposition are a consequential factor affecting the confidence which should be placed in head film comparisons, particularly with regard to individual cases. Some consequences of this conclusion with respect to growth prediction and to the evaluation of treatment effects are considered.

Identification case of evidence in timber tracing of Pinus radiate, using high-resolution melting (HRM) analysis.

Science.gov (United States)

Solano, Jaime; Anabalón, Leonardo; Encina, Francisco

2016-03-01

Fast, accurate detection of plant species and their hybrids using molecular tools will facilitate assessment and monitoring of timber tracing evidence. In this study the origin of unknown pine samples is determined for a case of timber theft in the region of Araucania southern Chile. We evaluate the utility of the trnL marker region for species identification applied to pine wood based on High Resolution Melting. This efficient tracing methods can be incorporated into forestry applications such as certification of origin. The object of this work was genotype identification using high-resolution melting (HRM) and trnL approaches for Pinus radiata (Don) in timber tracing evidence. Our results indicate that trnL is a very sensitive marker for delimiting species and HRM analysis was used successfully for genotyping Pinus samples for timber tracing purposes. Genotyping samples by HRM analysis with the trnL1 approach allowed us to differentiate two wood samples from the Pinaceae family: Pinus radiata (Don) and Pseudotsuga menziesii (Mirb.) Franco. The same approach with Pinus trnL wood was not able to discriminate between samples of Pinus radiata, indicating that the samples were genetically indistinguishable, possibly because they have the same genotype at this locus. Timber tracing with HRM analysis is expected to contribute to future forest certification schemes, control of illegal trading, and molecular traceability of Pinus spp. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Efficient Algorithms for Real-Time GPU Volumetric Cloud Rendering with Enhanced Geometry

OpenAIRE

Carlos Jiménez de Parga; Sebastián Rubén Gómez Palomo

2018-01-01

This paper presents several new techniques for volumetric cloud rendering using efficient algorithms and data structures based on ray-tracing methods for cumulus generation, achieving an optimum balance between realism and performance. These techniques target applications such as flight simulations, computer games, and educational software, even with conventional graphics hardware. The contours of clouds are defined by implicit mathematical expressions or triangulated structures inside which ...

Removing efficiency of radon from water by different methods

International Nuclear Information System (INIS)

Muellerova, M.; Holy, K.; Gulasova, Z.; Polaskova, A.

2008-01-01

In this contribution problem of radon removing from water samples by different methods was tested. Lowest efficiency of deemanation was achieved at tossing of water from one vessel into the other. For increasing of efficiency deemanation of radon use of needle-bath principle was also used. Low efficiency deemanation was found at trapping of radon from sample of water by toluene (83 ± 5) %, too. Reversal highest efficiency deemanation of radon from water was reached at aerating by argon (95 ± 6)%. It is shown, that reduction of volume activity of radon in water under 0.1 Bq/dm l - 3 is big problem. Suppression of this limit will claim use of more completion and sophistic approaches. (author)

An Overview Of Tool For Response Action Cost Estimating (TRACE)

International Nuclear Information System (INIS)

Ferries, S.R.; Klink, K.L.; Ostapkowicz, B.

2012-01-01

Tools and techniques that provide improved performance and reduced costs are important to government programs, particularly in current times. An opportunity for improvement was identified for preparation of cost estimates used to support the evaluation of response action alternatives. As a result, CH2M HILL Plateau Remediation Company has developed Tool for Response Action Cost Estimating (TRACE). TRACE is a multi-page Microsoft Excel(reg s ign) workbook developed to introduce efficiencies into the timely and consistent production of cost estimates for response action alternatives. This tool combines costs derived from extensive site-specific runs of commercially available remediation cost models with site-specific and estimator-researched and derived costs, providing the best estimating sources available. TRACE also provides for common quantity and key parameter links across multiple alternatives, maximizing ease of updating estimates and performing sensitivity analyses, and ensuring consistency.

Consumer perception of Brazilian traced beef

Directory of Open Access Journals (Sweden)

Júlio Otávio Jardim Barcellos

2012-03-01

Full Text Available The objective of this study was to determine consumers understanding of beef traceability, identifying how consumers value this meat and traceability elements to be presented on retail shelves. The method used in this study was a survey through the internet applying the Sphinx software. The sample consisted of 417 consumers, mostly living in Porto Alegre, Brazil. Consumers are aware of certified beef, consider it important, but this is not a demand. As to traced beef, most consumers (62.4% are in favor of mandatory traceability of beef cattle in Brazil, but 86.6% disagree with the destination of traced beef only to the foreign market. The majority of people are willing to pay more for traced beef and consider traceability a market opportunity, used as a differentiating tool.

Application of neutron activation and high resolution X-ray spectrometry to the development of analytical methods suitable for the assay of trace elements in biological materials. Part of a coordinated programme on comparative methods for the study of trace elements in human nutrition

International Nuclear Information System (INIS)

Mantel, J.

1980-12-01

A new method for determining trace elements in biological materials by instrumental neutron activation analysis (INAA) has been investigated. This method is based on the measurement of low-energy X-rays emitted by the sample after appropriate activation with thermal neutrons. The X-rays were detected by a Si(Li) diode connected to a multichannel analyser. The background in the energy region of interest was reduced by means of an electromagnet which deflects high-energy beta-particles away from the detector. This method of measurement has been evaluated by application to a number of different biological reference materials. The use of the electromagnet for background reduction was shown to be extremely effective for several radionuclides that are common sources of disturbance in INAA. For 32 P the background was only 0.8% of its original value. For real samples the background reduction depends somewhat on the matrix and therefore varies from one material to another. Practical detection limits for typical biological materials were derived for 18 different trace elements. The use of a perspex absorber was also considered as an alternative to magnetic deflection of the beta rays. In practice, magnetic deflection is preferable for the lower-energy X-ray emitters such as the activation products of Co, Cr, Cu and Zn

Polarographic determination of trace amounts of thorium

Energy Technology Data Exchange (ETDEWEB)

Zaofan Zhao; Xiaohua Cai; Peibiao Li; Handong Yang

1986-07-01

A sensitive linear-sweep polarographic method for the determination of thorium is described. It is based on the thorium complex with Xylidyl Blue I (XBI) in a medium containing ethylenediamine, 1, 10-phenanthroline, oxalic acid and ninhydrin, at pH 10.5-11.5. The complex has been proved to be Th(XBI)/sub 2/, with log ..beta..'=9.6. The method can be used to determine trace amounts of thorium over the range 3.5x10/sup -8/-3x10/sup -6/M. The detection limit is 1x10/sup -8/M. A solvent extraction procedure is necessary to eliminate interference from several cations. The method has been applied to determination of traces of thorium in minerals, with good results.

TiO_2 assisted photo-oxidation of wastewater prior to voltammetric determination of trace metals: Eco-friendly alternative to traditional digestion methods

International Nuclear Information System (INIS)

Lejbt, Beata; Ospina-Alvarez, Natalia; Miecznikowski, Krzysztof; Krasnodębska-Ostręga, Beata

2016-01-01

Highlights: • Cheap and eco-friendly method using anatase-assisted photodecomposition to pre-treat wastewater samples prior to trace metal analysis. • Addition of polyvinylidene fluoride did not affect the efficiency of organic matter decomposition. • TiO_2 assisted photo-oxidation procedure is equally effective than ICP MS determination after UV assisted digestion with H_2O_2 addition. - Abstract: Voltammetry is a sensitive method for metal determination and one alternative to ICP MS, but its limitation is the influence of the organic matrix on the measurements. To avoid those interferences, wet digestion with H_2O_2 accelerated with UV irradiation is applied and evaporation of excess of reagents is required. In this study, photolytic oxidation in quartz tubes with anatase was carried out, using as object of study wastewater samples with high amount of organic matter. Cadmium and lead determination was carried out in order to test metal recoveries. Lead recoveries reached c.a 85% for UV digestion with hydrogen peroxide, 98% for digestion with anatase immobilized with polyvinylidene fluoride (N-metylo-2-pirolidon) and c.a 103% for digestion with immobilized anatase (anatase in gum). The results obtained showed the usefulness of TiO_2 layer as an oxidation medium. An easy, cheap and eco-friendly digestion method of surfactants without any reagent has been developed, with equal sensitivity but and the same detection limit of traditional digestion methods.

Source apportionment of trace metals in river sediments: A comparison of three methods

International Nuclear Information System (INIS)

Chen, Haiyang; Teng, Yanguo; Li, Jiao; Wu, Jin; Wang, Jinsheng

2016-01-01

Increasing trace metal pollution in river sediment poses a significant threat to watershed ecosystem health. Identifying potential sources of sediment metals and apportioning their contributions are of key importance for proposing prevention and control strategies of river pollution. In this study, three advanced multivariate receptor models, factor analysis with nonnegative constraints (FA-NNC), positive matrix factorization (PMF), and multivariate curve resolution weighted-alternating least-squares (MCR-WALS), were comparatively employed for source apportionment of trace metals in river sediments and applied to the Le'an River, a main tributary of Poyang Lake which is the largest freshwater lake in China. The pollution assessment with contamination factor and geoaccumulation index suggested that the river sediments in Le'an River were contaminated severely by trace metals due to human activities. With the three apportionment tools, similar source profiles of trace metals in sediments were extracted. Especially, the MCR-WALS and PMF models produced essentially the same results. Comparatively speaking, the weighted schemes might give better solutions than the unweighted FA-NNC because the uncertainty information of environmental data was considered by PMF and MCR-WALS. Anthropogenic sources were apportioned as the most important pollution sources influencing the sediment metals in Le'an River with contributions of about 90%. Among them, copper tailings occupied the largest contribution (38.4–42.2%), followed by mining wastewater (29.0–33.5%), and agricultural activities (18.2–18.7%). To protect the ecosystem of Le'an River and Poyang Lake, special attention should be paid to the discharges of mining wastewater and the leachates of copper tailing ponds in that region. - Highlights: • Three advanced receptor models were comparatively employed for source apportionment. • The MCR-WALS and PMF models produce essentially same source profiles. • Copper

Determination of ultra-trace aluminum in human albumin by cloud point extraction and graphite furnace atomic absorption spectrometry

International Nuclear Information System (INIS)

Sun Mei; Wu Qianghua

2010-01-01

A cloud point extraction (CPE) method for the preconcentration of ultra-trace aluminum in human albumin prior to its determination by graphite furnace atomic absorption spectrometry (GFAAS) had been developed in this paper. The CPE method was based on the complex of Al(III) with 1-(2-pyridylazo)-2-naphthol (PAN) and Triton X-114 was used as non-ionic surfactant. The main factors affecting cloud point extraction efficiency, such as pH of solution, concentration and kind of complexing agent, concentration of non-ionic surfactant, equilibration temperature and time, were investigated in detail. An enrichment factor of 34.8 was obtained for the preconcentration of Al(III) with 10 mL solution. Under the optimal conditions, the detection limit of Al(III) was 0.06 ng mL -1 . The relative standard deviation (n = 7) of sample was 3.6%, values of recovery of aluminum were changed from 92.3% to 94.7% for three samples. This method is simple, accurate, sensitive and can be applied to the determination of ultra-trace aluminum in human albumin.

Determination of ultra-trace aluminum in human albumin by cloud point extraction and graphite furnace atomic absorption spectrometry

Energy Technology Data Exchange (ETDEWEB)

Sun Mei, E-mail: sunmei@ustc.edu.cn [Hefei National Laboratory for Physical Sciences on Microscale, University of Science and Technology of China, No. 96, Jinzhai Road, Hefei 230026 (China); Wu Qianghua [Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei 230026 (China)

2010-04-15

A cloud point extraction (CPE) method for the preconcentration of ultra-trace aluminum in human albumin prior to its determination by graphite furnace atomic absorption spectrometry (GFAAS) had been developed in this paper. The CPE method was based on the complex of Al(III) with 1-(2-pyridylazo)-2-naphthol (PAN) and Triton X-114 was used as non-ionic surfactant. The main factors affecting cloud point extraction efficiency, such as pH of solution, concentration and kind of complexing agent, concentration of non-ionic surfactant, equilibration temperature and time, were investigated in detail. An enrichment factor of 34.8 was obtained for the preconcentration of Al(III) with 10 mL solution. Under the optimal conditions, the detection limit of Al(III) was 0.06 ng mL{sup -1}. The relative standard deviation (n = 7) of sample was 3.6%, values of recovery of aluminum were changed from 92.3% to 94.7% for three samples. This method is simple, accurate, sensitive and can be applied to the determination of ultra-trace aluminum in human albumin.

New Efficient Fourth Order Method for Solving Nonlinear Equations

Directory of Open Access Journals (Sweden)

Farooq Ahmad

2013-12-01

Full Text Available In a paper [Appl. Math. Comput., 188 (2 (2007 1587--1591], authors have suggested and analyzed a method for solving nonlinear equations. In the present work, we modified this method by using the finite difference scheme, which has a quintic convergence. We have compared this modified Halley method with some other iterative of fifth-orders convergence methods, which shows that this new method having convergence of fourth order, is efficient.

Phytoaccumulation of trace elements by wetland plants: 3. Uptake and accumulation of ten trace elements by twelve plant species

Energy Technology Data Exchange (ETDEWEB)

Qian, J.H.; Zayed, A.; Zhu, Y.L.; Yu, M.; Terry, N.

1999-10-01

Interest is increasing in using wetland plants in constructed wetlands to remove toxic elements from polluted wastewater. To identify those wetland plants that hyperaccumulate trace elements, 12 plant species were tested for their efficiency to bioconcentrate 10 potentially toxic trace elements including As, b, Cd, Cr, Cu, Pb, Mn, Hg, Ni, and Se. Individual plants were grown under carefully controlled conditions and supplied with 1 mg L{sup {minus}1} of each trace element individually for 10 d. Except B, all elements accumulated to much higher concentrations in roots than in shoots. Highest shoot tissue concentrations (mg kg{sup {minus}1} DW) of the various trace elements were attained by the following species: umbrella plant (Cyperus alternifolius L.) for Mn (198) and Cr (44); water zinnia (Wedelia trilobata Hitchc.) for Cd (148) and Ni (80); smartweed (Polygonum hydropiperoides Michx.) for Cu (95) and Pb (64); water lettuce (Pistia stratiotes L.) for Hg (92), As (34), and Se (39); and mare's tail (hippuris vulgaris L.) for B (1132). Whereas, the following species attained the highest root tissue concentrations (mg kg{sup {minus}1} DW); stripped rush (Baumia rubiginosa) for Mn (1683); parrot's feather (Myriophyllum brasiliense Camb.) for Cd (1426) and Ni (1077); water lettuce for Cu (1038), Hg (1217), and As (177); smartweed for Cr (2980) and Pb (1882); mare's tail for B (1277); and monkey flower (Mimulus guttatus Fisch.) for Se (384). From a phytoremediation perspective, smartweed was probably the best plant species for trace element removal from wastewater due to its faster growth and higher plant density.

A Computer Library for Ray Tracing in Analytical Media

International Nuclear Information System (INIS)

Miqueles, Eduardo; Coimbra, Tiago A; Figueiredo, J J S de

2013-01-01

Ray tracing technique is an important tool not only for forward but also for inverse problems in Geophysics, which most of the seismic processing steps depends on. However, implementing ray tracing codes can be very time consuming. This article presents a computer library to trace rays in 2.5D media composed by stack of layers. The velocity profile inside each layer is such that the eikonal equation can be analitically solved. Therefore, the ray tracing within such profile is made fast and accurately. The great advantage of an analytical ray tracing library is the numerical precision of the quantities computed and the fast execution of the implemented codes. Although ray tracing programs already exist for a long time, for example the seis package by Cervený, with a numerical approach to compute the ray. Regardless of the fact that numerical methods can solve more general problems, the analytical ones could be part of a more sofisticated simulation process, where the ray tracing time is completely relevant. We demonstrate the feasibility of our codes using numerical examples.

TRACE/PARCS modelling of rips trip transients for Lungmen ABWR

Energy Technology Data Exchange (ETDEWEB)

Chang, C. Y. [Inst. of Nuclear Engineering and Science, National Tsing-Hua Univ., No.101, Kuang-Fu Road, Hsinchu 30013, Taiwan (China); Lin, H. T.; Wang, J. R. [Inst. of Nuclear Energy Research, No. 1000, Wenhua Rd., Longtan Township, Taoyuan County 32546, Taiwan (China); Shih, C. [Inst. of Nuclear Engineering and Science, Dept. of Engineering and System Science, National Tsing-Hua Univ., No.101, Kuang-Fu Road, Hsinchu 30013, Taiwan (China)

2012-07-01

The objectives of this study are to examine the performances of the steady-state results calculated by the Lungmen TRACE/PARCS model compared to SIMULATE-3 code, as well as to use the analytical results of the final safety analysis report (FSAR) to benchmark the Lungmen TRACE/PARCS model. In this study, three power generation methods in TRACE were utilized to analyze the three reactor internal pumps (RIPs) trip transient for the purpose of validating the TRACE/PARCS model. In general, the comparisons show that the transient responses of key system parameters agree well with the FSAR results, including core power, core inlet flow, reactivity, etc. Further studies will be performed in the future using Lungmen TRACE/PARCS model. After the commercial operation of Lungmen nuclear power plant, TRACE/PARCS model will be verified. (authors)

Trace element studies at University of Pittsburgh

International Nuclear Information System (INIS)

Cohen, B.L.; Chan, K.C.; Shabason, L.; Wedberg, G.; Rudolph, H.

1974-01-01

Seven areas of research are discussed. A method was developed for analyzing samples for their major constituent elements by irradiating with protons and detecting prompt gamma rays, mostly produced in (p,p'γ) reactions. Among other applications, the method was used to analyze air particulates for C, N, O, Al, Si, S, Co, and Fe. Trace element analysis by proton or alpha particle induced x-ray fluorescence was used on thin samples in a study of the variations of Pb, Br, Fe, and Zn in air particulates as a function of time. Among other applications this method was also used in studying trace elements in rainwater. An x-ray fluorescence method that is effective in the analysis of thick samples was developed. A method based on measuring energies of elastically scattered protons was developed for the analysis of light elements. The use of proton and neutron activation analyses, as well as methods for studying depth profiles for hydrogen and helium in materials are discussed

Trace analysis of actinides in the environment using resonance ionization mass spectrometry; Spurenanalyse von Aktiniden in der Umwelt mittels Resonanzionisations-Massenspektrometrie

Energy Technology Data Exchange (ETDEWEB)

Raeder, Sebastian

2011-04-12

In this work the resonant ionization of neutral atoms using laser radiation was applied and optimized for ultra-trace analysis of the actinides thorium, uranium, neptunium and plutonium. The sensitive detection of these actinides is a challange for the monitoring and quantification of radioactive releases from nuclear facilities. Using resonance ionization spectroscopy combined with a newly developed quadrupole-mass-spectrometer, numerous energy levels in the atomic structure of these actinides could be identified. With this knowledge efficient excitation schemes for the mentioned actinides could be identified and characterised. The applied in-source-ionization ensures for a high detection efficiency due to the good overlap of laser radiation with the atomic beam and allows therefore for a low sample consumption which is required for the analysis of radio nuclides. The selective excitation processes in the resonant ionization method supresses unwanted contaminations and was optimized for analytical detection of ultra-trace amounts in environmental samples as well as for determination of isotopic compositions. The efficient in-source-ionization combined with high power pulsed laser radiation allows for detections efficiency up to 1%. For plutonium detection limits in the range of 10{sup 4}-10{sup 5} atoms could be demonstrated for synthetic samples as well as for first environmental samples. The usage of narrow bandwidth continuous wave lasers in combination with a transversal overlap of the laser radiation and the free propagating atomic beam enable for resolving individual isotopic shifts of the resonant transitions. This results in a high selectivity against dominant neighboring isotopes but with a significant loss in detection efficiency. For the ultra-trace isotope {sup 236}U a detection limit down to 10{sup -9} for the isotope ratio N ({sup 236}U)/N ({sup 238}U) could be determined.

Extreme-Scale Stochastic Particle Tracing for Uncertain Unsteady Flow Analysis

Energy Technology Data Exchange (ETDEWEB)

Guo, Hanqi; He, Wenbin; Seo, Sangmin; Shen, Han-Wei; Peterka, Tom

2016-11-13

We present an efficient and scalable solution to estimate uncertain transport behaviors using stochastic flow maps (SFM,) for visualizing and analyzing uncertain unsteady flows. SFM computation is extremely expensive because it requires many Monte Carlo runs to trace densely seeded particles in the flow. We alleviate the computational cost by decoupling the time dependencies in SFMs so that we can process adjacent time steps independently and then compose them together for longer time periods. Adaptive refinement is also used to reduce the number of runs for each location. We then parallelize over tasks—packets of particles in our design—to achieve high efficiency in MPI/thread hybrid programming. Such a task model also enables CPU/GPU coprocessing. We show the scalability on two supercomputers, Mira (up to 1M Blue Gene/Q cores) and Titan (up to 128K Opteron cores and 8K GPUs), that can trace billions of particles in seconds.

Trace gas emissions from burning Florida wetlands

Science.gov (United States)

Cofer, Wesley R.; Levine, Joel S.; Winstead, Edward L.; Lebel, Peter J.; Koller, Albert M.; Hinkle, C. Ross

1990-02-01

Measurements of biomass burn-produced trace gases are presented that were obtained using a helicopter at low altitudes above burning Florida wetlands on November 9, 1987, and from both helicopter and light-aircraft samplings on November 7, 1988. Carbon dioxide (CO2) normalized emission ratios (ΔX/ΔCO2; V/V; where X is trace gas) for carbon monoxide (CO), hydrogen (H2), methane (CH4), total nonmethane hydrocarbons (TNMHC), and nitrous oxide (N2O) were obtained over burning graminoid wetlands consisting primarily of Spartina bakeri and Juncus roemerianus. Some interspersed scrub oak (Quercus spp) and saw palmetto (Screnoa repens) were also burned. No significant differences were observed in the emission ratios determined for these gases from samples collected over flaming, mixed, and smoldering phases of combustion during the 1987 fire. Combustion-categorized differences in emission ratios were small for the 1988 fire. Combustion efficiency was relatively good (low emission ratios for reduced gases) for both fires. We believe that the consistently low emission ratios were a unique result of graminoid wetlands fires, in which the grasses and rushes (both small-size fuels) burned rapidly down to standing water and were quickly extinguished. Consequently, the efficiency of the combustion was good and the amount and duration of smoldering combustion was greatly diminished.

AXAF FITS standard for ray trace interchange

Science.gov (United States)

Hsieh, Paul F.

1993-07-01

A standard data format for the archival and transport of x-ray events generated by ray trace models is described. Upon review and acceptance by the Advanced X-ray Astrophysics Facility (AXAF) Software Systems Working Group (SSWG), this standard shall become the official AXAF data format for ray trace events. The Flexible Image Transport System (FITS) is well suited for the purposes of the standard and was selected to be the basis of the standard. FITS is both flexible and efficient and is also widely used within the astronomical community for storage and transfer of data. In addition, software to read and write FITS format files are widely available. In selecting quantities to be included within the ray trace standard, the AXAF Mission Support team, Science Instruments team, and the other contractor teams were surveyed. From the results of this survey, the following requirements were established: (1) for the scientific needs, each photon should have associated with it: position, direction, energy, and statistical weight; the standard must also accommodate path length (relative phase), and polarization. (2) a unique photon identifier is necessary for bookkeeping purposes; (3) a log of individuals, organizations, and software packages that have modified the data must be maintained in order to create an audit trail; (4) a mechanism for extensions to the basic kernel should be provided; and (5) the ray trace standard should integrate with future AXAF data product standards.

Application of radio-reagent method in the determination of lead trace amounts

International Nuclear Information System (INIS)

Figueiredo, A.M.G.

1983-01-01

A radiometric method for trace analysis of lead was established, based on the displacement reaction between lead and the complex cobalt - ethylenediaminetetracetate labelled with 60 Co (Co* - EDTA), which is named radioreagent. The radioactive cobalt displaced by lead is separated from the excess of radioreagent by the solvent extraction technique, using a solution of tetracycline (Tc) in benzyl alcohol. The activity of the extracted cobalt is then measured by means of a single-channel gamma-ray analyser coupled to a NaI (Tl) scintillation detector, the activity being proportional to the lead concentration, in a range from 2.5 to 150 μg. The interference of several elements (V, Th, Sc, Fe, La, Yb, Cu, Cd, Zn, Mn, Ni, Co, Al and Sn) was investigated by means of a previous separation between lead and these interfering elements. The analyses of artificial samples containing lead and the interfering elements gave a yield of 91.1 + - 3.2 %. The detection limit achieved by the method was 3.3 μg of lead. The radioreagent method was applied to lead analysis of samples from IAEA, namely: simulated air filter (Air-3), fresh water (W-3), dried animal blood (A-2) and calcinated animal bone (A-3/1). Lead was also determined in gasoline samples and air samples, these latter collected in the surroundings of the IPEN/CNEN/SP (Brazil). (Author) [pt

Detecting Android Malwares with High-Efficient Hybrid Analyzing Methods

Directory of Open Access Journals (Sweden)

Yu Liu

2018-01-01

Full Text Available In order to tackle the security issues caused by malwares of Android OS, we proposed a high-efficient hybrid-detecting scheme for Android malwares. Our scheme employed different analyzing methods (static and dynamic methods to construct a flexible detecting scheme. In this paper, we proposed some detecting techniques such as Com+ feature based on traditional Permission and API call features to improve the performance of static detection. The collapsing issue of traditional function call graph-based malware detection was also avoided, as we adopted feature selection and clustering method to unify function call graph features of various dimensions into same dimension. In order to verify the performance of our scheme, we built an open-access malware dataset in our experiments. The experimental results showed that the suggested scheme achieved high malware-detecting accuracy, and the scheme could be used to establish Android malware-detecting cloud services, which can automatically adopt high-efficiency analyzing methods according to the properties of the Android applications.

Novel colorimetric method overcoming phosphorus interference during trace arsenic analysis in soil solution.

Science.gov (United States)

Makris, Konstantinos C; Punamiya, Pravin; Sarkar, Dibyendu; Datta, Rupali

2008-02-01

A sensitive (method detection limit, 2.0 microg As L(-1)) colorimetric determination of trace As(v) and As(iii) concentrations in the presence of soluble phosphorus (P) concentrations in soil/water extracts is presented. The proposed method modifies the malachite green method (MG) originally developed for P in soil and water. Our method relies upon the finding that As(iii) and As(v) do not develop the green color during P analysis using the MG method. When an optimum concentration of ascorbic acid (AA) is added to a sample containing up to 15 times P > As (microM) concentrations, the final sample absorbance due to P will be equal to that of As(v) molecules. The soluble As concentration can then be quantified by the concentration difference between the mixed oxyanion (As + P) absorbance (proposed method) and the MG method absorbance that measures only P. Our method is miniaturized using a 96-well microplate UV-VIS reader that utilizes minute reagent and sample volumes (120 and 200 microL sample(-1), respectively), thus, minimizing waste and offering flexibility in the field. Our method was tested in a suite of As-contaminated soils that successfully measured both As and P in soil water extracts and total digests. Mean% As recoveries ranged between 84 and 117%, corroborating data obtained with high-resolution inductively-coupled plasma mass-spectrometry. The performance of the proposed colorimetric As method was unaffected by the presence of Cu, Zn, Pb, Ni, Fe, Al, Si, and Cr in both neutral and highly-acidic (ca. pH 2) soil extracts. Data from this study provide the proof of concept towards creating a field-deployable, portable As kit.

Trace elements in brazilian soils

International Nuclear Information System (INIS)

Rocha, Geraldo Cesar

1995-01-01

A literature revision on trace elements (Zn, B, Mn, Mo, Cu, Fe, and Cl) in Brazilian soils was prepared, with special attention to the chemical form and range in the soil, extraction methods and correlation of the amount in soils with soil properties

Highly selective solid-phase extraction of trace Pd(II) by murexide functionalized halloysite nanotubes

Energy Technology Data Exchange (ETDEWEB)

Li Ruijun; He Qun; Hu Zheng; Zhang Shengrui [Department of Chemistry, Lanzhou University, Lanzhou 730000 (China); Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, Lanzhou 730000 (China); Zhang Lijun [Faculty of Science and Engineer, Curtin University, Perth, WA 6845 (Australia); Chang Xijun, E-mail: lirj2010@lzu.edu.cn [Department of Chemistry, Lanzhou University, Lanzhou 730000 (China); Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, Lanzhou 730000 (China)

2012-02-03

Graphical abstract: Murexide functionalized halloysite nanotubes have been developed to separate and concentrate trace Pd(II) from aqueous samples. Parameters that affected the sorption and elution efficiency were studied in column mode, and the new adsorbent presented high selectivity and adsorption capacity for the solid phase extraction of trace Pd(II). Highlights: Black-Right-Pointing-Pointer Murexide modified halloysite nanotubes as adsorbent has been reported originally. Black-Right-Pointing-Pointer This adsorbent has a unique selectivity for Pd(II) at pH 1.0. Black-Right-Pointing-Pointer This adsorbent had high adsorption capacity for Pd(II). Black-Right-Pointing-Pointer The precision and accuracy of the method are satisfactory. - Abstract: The originality on the high efficiency of murexide modified halloysite nanotubes as a new adsorbent of solid phase extraction has been reported to preconcentrate and separate Pd(II) in solution samples. The new adsorbent was confirmed by Fourier transformed infrared spectra, X-ray diffraction, scanning electron microscope, transmission electron microscope and N{sub 2} adsorption-desorption isotherms. Effective preconcentration conditions of analyte were examined using column procedures prior to detection by inductively coupled plasma-optical emission spectrometry (ICP-OES). The effects of pH, the amount of adsorbent, the sample flow rate and volume, the elution condition and the interfering ions were optimized in detail. Under the optimized conditions, Pd(II) could be retained on the column at pH 1.0 and quantitatively eluted by 2.5 mL of 0.01 mol L{sup -1} HCl-3% thiourea solution at a flow rate of 2.0 mL min{sup -1}. The analysis time was 5 min. An enrichment factor of 120 was accomplished. Common interfering ions did not interfere in both separation and determination. The maximum adsorption capacity of the adsorbent at optimum conditions was found to be 42.86 mg g{sup -1} for Pd(II). The detection limit (3{sigma}) of

Highly selective solid-phase extraction of trace Pd(II) by murexide functionalized halloysite nanotubes

International Nuclear Information System (INIS)

Li Ruijun; He Qun; Hu Zheng; Zhang Shengrui; Zhang Lijun; Chang Xijun

2012-01-01

Graphical abstract: Murexide functionalized halloysite nanotubes have been developed to separate and concentrate trace Pd(II) from aqueous samples. Parameters that affected the sorption and elution efficiency were studied in column mode, and the new adsorbent presented high selectivity and adsorption capacity for the solid phase extraction of trace Pd(II). Highlights: ► Murexide modified halloysite nanotubes as adsorbent has been reported originally. ► This adsorbent has a unique selectivity for Pd(II) at pH 1.0. ► This adsorbent had high adsorption capacity for Pd(II). ► The precision and accuracy of the method are satisfactory. - Abstract: The originality on the high efficiency of murexide modified halloysite nanotubes as a new adsorbent of solid phase extraction has been reported to preconcentrate and separate Pd(II) in solution samples. The new adsorbent was confirmed by Fourier transformed infrared spectra, X-ray diffraction, scanning electron microscope, transmission electron microscope and N 2 adsorption–desorption isotherms. Effective preconcentration conditions of analyte were examined using column procedures prior to detection by inductively coupled plasma-optical emission spectrometry (ICP-OES). The effects of pH, the amount of adsorbent, the sample flow rate and volume, the elution condition and the interfering ions were optimized in detail. Under the optimized conditions, Pd(II) could be retained on the column at pH 1.0 and quantitatively eluted by 2.5 mL of 0.01 mol L −1 HCl–3% thiourea solution at a flow rate of 2.0 mL min −1 . The analysis time was 5 min. An enrichment factor of 120 was accomplished. Common interfering ions did not interfere in both separation and determination. The maximum adsorption capacity of the adsorbent at optimum conditions was found to be 42.86 mg g −1 for Pd(II). The detection limit (3σ) of the method was 0.29 ng mL −1 , and the relative standard deviation (RSD) was 3.1% (n = 11). The method was

A sensitive flow-batch system for on board determination of ultra-trace ammonium in seawater: Method development and shipboard application.

Science.gov (United States)

Zhu, Yong; Yuan, Dongxing; Huang, Yongming; Ma, Jian; Feng, Sichao

2013-09-10

Combining fluorescence detection with flow analysis and solid phase extraction (SPE), a highly sensitive and automatic flow system for measurement of ultra-trace ammonium in open ocean water was established. Determination was based on fluorescence detection of a typical product of o-phthaldialdehyde and ammonium. In this study, the fluorescence reaction product could be efficiently extracted onto an SPE cartridge (HLB, hydrophilic-lipophilic balance). The extracted fluorescence compounds were rapidly eluted with ethanol and directed into a flow cell for fluorescence detection. Compared with the common used fluorescence method, the proposed one offered the benefits of improved sensitivity, reduced reagent consumption, negligible salinity effect and lower cost. Experimental parameters were optimized using a univariate experimental design. Calibration curves, ranging from 1.67 to 300nM, were obtained with different reaction times. The recoveries were between 89.5 and 96.5%, and the detection limits in land-based and shipboard laboratories were 0.7 and 1.2nM, respectively. The relative standard deviation was 3.5% (n=5) for an aged seawater sample spiked with 20nM ammonium. Compared with the analytical results obtained using the indophenol blue method coupled to a long-path liquid waveguide capillary cell, the proposed method showed good agreement. The method had been applied on board during a South China Sea cruise in August 2012. A vertical profile of ammonium in the South East Asia Time-Series (SEATS, 18° N, 116° E) station was produced. The distribution of ammonium in the surface seawater of the Qiongdong upwelling in South China Sea is also presented. Copyright © 2013 Elsevier B.V. All rights reserved.

Bulk derivatization and cation exchange restricted access media-based trap-and-elute liquid chromatography–mass spectrometry method for determination of trace estrogens in serum

Energy Technology Data Exchange (ETDEWEB)

Beinhauer, Jana [Department of Biochemistry, Faculty of Science, Palacký University, Šlechtitelů 11, CZ-783 71 Olomouc (Czech Republic); Centre of the Region Haná for Biotechnological and Agricultural Research - Department of Protein Biochemistry and Proteomics, Faculty of Science, Palacký University, Šlechtitelů 11, CZ-783 71 Olomouc (Czech Republic); Bian, Liangqiao [Shimadzu Center for Advanced Analytical Chemistry, The University of Texas at Arlington, Arlington, TX (United States); Shimadzu Institute for Research Technologies, The University of Texas at Arlington, Arlington, TX (United States); Fan, Hui [Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX (United States); Šebela, Marek [Department of Biochemistry, Faculty of Science, Palacký University, Šlechtitelů 11, CZ-783 71 Olomouc (Czech Republic); Centre of the Region Haná for Biotechnological and Agricultural Research - Department of Protein Biochemistry and Proteomics, Faculty of Science, Palacký University, Šlechtitelů 11, CZ-783 71 Olomouc (Czech Republic); Kukula, Maciej [Shimadzu Center for Advanced Analytical Chemistry, The University of Texas at Arlington, Arlington, TX (United States); Shimadzu Institute for Research Technologies, The University of Texas at Arlington, Arlington, TX (United States); Barrera, Jose A. [Shimadzu Institute for Research Technologies, The University of Texas at Arlington, Arlington, TX (United States); and others

2015-02-09

Highlights: • Analysis of estrogens in small volume samples at low parts-per-trillion concentration. • Charged bulk derivatization facilitates on-line ion exchange sample preparation. • On-line WCX restricted access media traps analytes, but not proteins and lipids. • Complete preparation and LC–MS/MS analysis completed in 30 min/sample. - Abstract: Estrone (E1), estradiols (α/β-E2), and estriol (E3) are four major metabolically active estrogens exerting strong biological activities at very low circulating concentrations. This paper reports a sensitive and efficient method with automated, on-line clean-up and detection to determine trace estrogens in a small volume of serum samples using liquid chromatography–electrospray ionization–tandem mass spectrometry directly, without off-line liquid–liquid or solid-phase extraction pretreatments. Serum aliquots (charcoal stripped fetal bovine serum, 100 μL) were spiked with four estrogen standards and their corresponding isotope-labeled internal standards, then bulk derivatized with 2-fluoro-1-methyl-pyridium p-toluenesulfonate (2-FMP) to establish the calibration curves and perform method validation. Calibration was established in the concentration ranges of 5–1000 pg mL{sup −1}, and demonstrated good linearity of R{sup 2} from 0.9944 to 0.9997 for the four derivatized estrogens. The lower detection limits obtained were 3–7 pg mL{sup −1}. Good accuracy and precision in the range of 86–112% and 2.3–11.9%, respectively, were observed for the quality control (QC) samples at low, medium, and high concentration levels. The stability tests showed that the derivatized serum samples were stable 8 h after derivatization at room temperature and at least to 48 h if stored at −20 °C. The method was applied to measure trace estrogens in real human and bovine serum samples, and three of four estrogen compounds studied were observed and quantified.

Virtual Ray Tracing as a Conceptual Tool for Image Formation in Mirrors and Lenses

Science.gov (United States)

Heikkinen, Lasse; Savinainen, Antti; Saarelainen, Markku

2016-01-01

The ray tracing method is widely used in teaching geometrical optics at the upper secondary and university levels. However, using simple and straightforward examples may lead to a situation in which students use the model of ray tracing too narrowly. Previous studies show that students seem to use the ray tracing method too concretely instead of…

Study on highly efficient seismic data acquisition and processing methods based on sparsity constraint

Science.gov (United States)

Wang, H.; Chen, S.; Tao, C.; Qiu, L.

2017-12-01

High-density, high-fold and wide-azimuth seismic data acquisition methods are widely used to overcome the increasingly sophisticated exploration targets. The acquisition period is longer and longer and the acquisition cost is higher and higher. We carry out the study of highly efficient seismic data acquisition and processing methods based on sparse representation theory (or compressed sensing theory), and achieve some innovative results. The theoretical principles of highly efficient acquisition and processing is studied. We firstly reveal sparse representation theory based on wave equation. Then we study the highly efficient seismic sampling methods and present an optimized piecewise-random sampling method based on sparsity prior information. At last, a reconstruction strategy with the sparsity constraint is developed; A two-step recovery approach by combining sparsity-promoting method and hyperbolic Radon transform is also put forward. The above three aspects constitute the enhanced theory of highly efficient seismic data acquisition. The specific implementation strategies of highly efficient acquisition and processing are studied according to the highly efficient acquisition theory expounded in paragraph 2. Firstly, we propose the highly efficient acquisition network designing method by the help of optimized piecewise-random sampling method. Secondly, we propose two types of highly efficient seismic data acquisition methods based on (1) single sources and (2) blended (or simultaneous) sources. Thirdly, the reconstruction procedures corresponding to the above two types of highly efficient seismic data acquisition methods are proposed to obtain the seismic data on the regular acquisition network. A discussion of the impact on the imaging result of blended shooting is discussed. In the end, we implement the numerical tests based on Marmousi model. The achieved results show: (1) the theoretical framework of highly efficient seismic data acquisition and processing

The chemical speciation and analysis of trace elements in sediment with Neutron Activation Analytical method(NAA) and atomic mass spectrometry

International Nuclear Information System (INIS)

Nam, Sang-Ho; Kim, Jae-Jin; Chung, Yong-Sam; Kim, Sun-Ha

2003-01-01

In this research, first of all, the analytical methods for the determination of major elements in sediment have been developed with ICP-MS (Inductively Coupled Plasma Mass Spectrometry). The analytical results of major elements (Al, Ca, K, Fe, Mg) with Cool ICP-MS were much better than those with normal ICP-MS. The analytical results were compared with those of NAA (Neutron Activation Analysis). NAA were a little superior to ICP-MS for the determination of major elements in sediment as a non-destructive trace analytical trace analytical method. The analytical methods for the determination of minor elements (Cr, Ce, U, Co, Pb, As, Se) have been also developed with ICP-MS. The analytical results by standard calibration curve with ICP-MS were not accurate due to the matrix interferences. Thus, the internal standard method was applied, then the analytical results for minor elements with ICP-MS were greatly improved. The analytical results obtained by ICP-MS were compared with those obtained by NAA. It showed that the two analytical methods have great capabilities for the determination of minor elements in sediments. Accordingly, the NAA will plan an important role in analysis of environment sample with complex matrix. ICP-MS also will play an important role because it has a great capability for the determination of Pb that could not be determined by NAA

Removal of trace metal contaminants from potable water by electrocoagulation

Science.gov (United States)

Heffron, Joe; Marhefke, Matt; Mayer, Brooke K.

2016-06-01

This study investigated the effects of four operational and environmental variables on the removal of trace metal contaminants from drinking water by electrocoagulation (EC). Removal efficiencies for five metals (arsenic, cadmium, chromium, lead and nickel) were compared under varying combinations of electrode material, post-treatment, water composition and pH. Iron electrodes out-performed aluminum electrodes in removing chromium and arsenic. At pH 6.5, aluminum electrodes were slightly more effective at removing nickel and cadmium, while at pH 8.5, iron electrodes were more effective for these metals. Regardless of electrode, cadmium and nickel removal efficiencies were higher at pH 8.5 than at pH 6.5. Post-EC treatment using membrane filtration (0.45 μm) enhanced contaminant removal for all metals but nickel. With the exception of lead, all metals exhibited poorer removal efficiencies as the ionic strength of the background electrolyte increased, particularly in the very high-solids synthetic groundwaters. Residual aluminum concentrations were lowest at pH 6.5, while iron residuals were lowest in low ionic strength waters. Both aluminum and iron residuals required post-treatment filtration to meet drinking water standards. EC with post-treatment filtration appears to effectively remove trace metal contaminants to potable water standards, but both reactor and source water parameters critically impact removal efficiency.

A radioagent method for determination of traces of phosphorus in high-purity silicon

International Nuclear Information System (INIS)

Chen, P.Y.; Chen, J.S.; Sun, H.J.; Yang, M.H.

1985-01-01

The feasibility of the determination of phosphorus at the extreme trace levels in high-purity silicon by radioreagent method is explored. After silicon dissolution with hydrofluoric and nitric acids and matrix volatilization, 12-molybdophosphoric acid is formed by the addition of the reagent, sup(99)MoOsub(4)sup(2-), in nitric acid medium and then extracted into isobutyl acetate. By plotting the phosphorus content against the radioactivity of sup(99)Mo in the organic phase, a linear relationship persisting down to 5 ng is obtained. Special effort was made to eliminate the unreacted sup(99)MoOsub(4)sup(2-) reagent and the optimal control of phosphorus blank introduced through the multistage analytical procedure in order to ensure reliable determination of phosphorus at the ppb level. (author)

A continuous in vitro method for estimation of the bioavailability of minerals and trace elements in foods : application to breads varying in phytic acid content

NARCIS (Netherlands)

Wolters, M.G.E.; Schreuder, H.A.W.; Heuvel, G. van den; Lonkhuijsen, H.J. van; Hermus, R.J.J.; Voragen, A.G.J.

1993-01-01

A continuous in vitro method for the estimation of the bioavailability of minerals and trace elements is presented. This in vitro method is believed to be more representative of in vivo physiological conditions than in vitro methods based on equilibrium dialysis, because dialysable components are

Determination of water traces in various organic solvents using Karl Fischer method under FIA conditions.

Science.gov (United States)

Dantan, N; Frenzel, W; Küppers, S

2000-05-31

Flow injection methods utilising the Karl Fischer (KF) reaction with spectrophotometric and potentiometric detection are described for the determination of the trace water content in various organic solvents. Optimisation of the methods resulted in an accessible (linear) working range of 0.01-0.2% water for many solvents studied with a typical precision of 1-2% R.S.D. Only 50 mul of organic solvent was injected and the sampling frequency was about 120 samples per h. Since the slopes of the calibration curves were different for different solvents appropriate calibration was required. Problems associated with spectrophotometric detection and caused by refractive index changes were pointed out and a nested-loop configuration was proposed to overcome this kind of interference. The potentiometric method with a novel flow-through detector cell was shown to surpass the performance of spectrophotometric detection in any respect. The characteristics of the procedures developed made them well applicable for on-line monitoring of technical solvent distillations in an industrial plant.

Memory Efficient PCA Methods for Large Group ICA.

Science.gov (United States)

Rachakonda, Srinivas; Silva, Rogers F; Liu, Jingyu; Calhoun, Vince D

2016-01-01

Principal component analysis (PCA) is widely used for data reduction in group independent component analysis (ICA) of fMRI data. Commonly, group-level PCA of temporally concatenated datasets is computed prior to ICA of the group principal components. This work focuses on reducing very high dimensional temporally concatenated datasets into its group PCA space. Existing randomized PCA methods can determine the PCA subspace with minimal memory requirements and, thus, are ideal for solving large PCA problems. Since the number of dataloads is not typically optimized, we extend one of these methods to compute PCA of very large datasets with a minimal number of dataloads. This method is coined multi power iteration (MPOWIT). The key idea behind MPOWIT is to estimate a subspace larger than the desired one, while checking for convergence of only the smaller subset of interest. The number of iterations is reduced considerably (as well as the number of dataloads), accelerating convergence without loss of accuracy. More importantly, in the proposed implementation of MPOWIT, the memory required for successful recovery of the group principal components becomes independent of the number of subjects analyzed. Highly efficient subsampled eigenvalue decomposition techniques are also introduced, furnishing excellent PCA subspace approximations that can be used for intelligent initialization of randomized methods such as MPOWIT. Together, these developments enable efficient estimation of accurate principal components, as we illustrate by solving a 1600-subject group-level PCA of fMRI with standard acquisition parameters, on a regular desktop computer with only 4 GB RAM, in just a few hours. MPOWIT is also highly scalable and could realistically solve group-level PCA of fMRI on thousands of subjects, or more, using standard hardware, limited only by time, not memory. Also, the MPOWIT algorithm is highly parallelizable, which would enable fast, distributed implementations ideal for big

Memory efficient PCA methods for large group ICA

Directory of Open Access Journals (Sweden)

Srinivas eRachakonda

2016-02-01

Full Text Available Principal component analysis (PCA is widely used for data reduction in group independent component analysis (ICA of fMRI data. Commonly, group-level PCA of temporally concatenated datasets is computed prior to ICA of the group principal components. This work focuses on reducing very high dimensional temporally concatenated datasets into its group PCA space. Existing randomized PCA methods can determine the PCA subspace with minimal memory requirements and, thus, are ideal for solving large PCA problems. Since the number of dataloads is not typically optimized, we extend one of these methods to compute PCA of very large datasets with a minimal number of dataloads. This method is coined multi power iteration (MPOWIT. The key idea behind MPOWIT is to estimate a subspace larger than the desired one, while checking for convergence of only the smaller subset of interest. The number of iterations is reduced considerably (as well as the number of dataloads, accelerating convergence without loss of accuracy. More importantly, in the proposed implementation of MPOWIT, the memory required for successful recovery of the group principal components becomes independent of the number of subjects analyzed. Highly efficient subsampled eigenvalue decomposition techniques are also introduced, furnishing excellent PCA subspace approximations that can be used for intelligent initialization of randomized methods such as MPOWIT. Together, these developments enable efficient estimation of accurate principal components, as we illustrate by solving a 1600-subject group-level PCA of fMRI with standard acquisition parameters, on a regular desktop computer with only 4GB RAM, in just a few hours. MPOWIT is also highly scalable and could realistically solve group-level PCA of fMRI on thousands of subjects, or more, using standard hardware, limited only by time, not memory. Also, the MPOWIT algorithm is highly parallelizable, which would enable fast, distributed implementations

Analysis of Power Transfer Efficiency of Standard Integrated Circuit Immunity Test Methods

Directory of Open Access Journals (Sweden)

Hai Au Huynh

2015-01-01

Full Text Available Direct power injection (DPI and bulk current injection (BCI methods are defined in IEC 62132-3 and IEC 62132-4 as the electromagnetic immunity test method of integrated circuits (IC. The forward power measured at the RF noise generator when the IC malfunctions is used as the measure of immunity level of the IC. However, the actual power that causes failure in ICs is different from forward power measured at the noise source. Power transfer efficiency is used as a measure of power loss of the noise injection path. In this paper, the power transfer efficiencies of DPI and BCI methods are derived and validated experimentally with immunity test setup of a clock divider IC. Power transfer efficiency varies significantly over the frequency range as a function of the test method used and the IC input impedance. For the frequency range of 15 kHz to 1 GHz, power transfer efficiency of the BCI test was constantly higher than that of the DPI test. In the DPI test, power transfer efficiency is particularly low in the lower test frequency range up to 10 MHz. When performing the IC immunity tests following the standards, these characteristics of the test methods need to be considered.

An efficient method for evaluating RRAM crossbar array performance

Science.gov (United States)

Song, Lin; Zhang, Jinyu; Chen, An; Wu, Huaqiang; Qian, He; Yu, Zhiping

2016-06-01

An efficient method is proposed in this paper to mitigate computational burden in resistive random access memory (RRAM) array simulation. In the worst case scenario, a 4 Mb RRAM array with line resistance is greatly reduced using this method. For 1S1R-RRAM array structures, static and statistical parameters in both reading and writing processes are simulated. Error analysis is performed to prove the reliability of the algorithm when line resistance is extremely small compared with the junction resistance. Results show that high precision is maintained even if the size of RRAM array is reduced by one thousand times, which indicates significant improvements in both computational efficiency and memory requirements.

Trace element analysis of wild rodent tissues using the PIXE method

International Nuclear Information System (INIS)

Hill, M.W.; Mangelson, N.F.; Ryder, J.F.; Atwood, N.D.; Wood, B.W.

1980-01-01

Five species of rodents have been collected in an area near Lake Powell Utah. Common names of the five species are: Long-tailed Mouse, Small Pocket Mouse, Deer Mouse, Antelope Ground Squirrel and Kangaroo Rat. Liver, lung, kidney and hair tissues from each animal were analyzed for trace element content by proton particle-induced x-ray emission (proton PIXE) analysis. Mean concentrations for the following elements were established for the tissues of each animal type: K, Ca, Ti, Mn, Fe, Ni, Cu, Zn, Se, Br, Rb and Pb. Analyses of variance were performed on the set of elements common to all tissues. Some significant differences in element concentrations were found between animal species and between tissue types. These differences lead to the following orders based on element concentration: Long-tailed Mouse greater than or equal to Antelope Ground Squirrel greater than or equal to Kangaroo Rat greater than or equal to Small Pocket Mouse and liver greater than or equal to kidney greater than or equal to lung greater than or equal to hair. Linear regression analyses were also performed on mean elemental concentrations in tissues. These analyses lead to several conclusions. First, the pattern of trace element concentrations in each of the four tissues is the same in all five species. Second, the pattern of trace element concentrations is the same in all four tissues of one species with the exception of Ti and Fe in hair. Third, the variation of an element in the hair cannot predict the variation of that same element in the other three tissues. Only K, Ca, Ti, Mn, Fe, Cu, and Zn were included in the third study

[Ferumoxide labeled Flk1+ CD31- CD34- human bone marrow mesenchymal stem cells and its in vivo tracing in the brains of Macaca Fascicularis].

Science.gov (United States)

Feng, Ming; Wang, Ren-Zhi; Zhu, Hua; Zhang, Nan; Wang, Chang-Jun; Wei, Jun-Ji; Lu, Shan; Li, Qin; Yin, Xiao-Ming; Han, Qin; Ma, Wen-Bin; Qin, Chuang; Zhao, Chun-Hua; An, Yi-Hua; Kong, Yan-Guo

2008-10-01

To explore the method for labeling Flk1+ CD31- CD34- human bone marrow mesenchymal stem cells (hBMSCs) with ferumoxide-PLL and evaluate the feasibility of its tracing after transplantation into the brains of Macaca Fascicularis. The hBMSCs were incubated with ferumoxide-PLL. Trypan blue staining, Prussian blue staining, and transmission electron microscope were performed to show intracellular iron, marking efficiency, and the vigor of the labeled cells. After the hBMSCs were transplanted into the brains of cynomolgus monkeys by stereotaxis, magnetic resonance imaging (MRI) was performed to trace the cells in vivo. Cell survival and differentiation were studied with immunohistochemistry, Prussian blue staining, and HE staining. The marking efficiency of the ferumoxide-PLL was 96%. Iron particles were found intracytoplasmic of the hBMSCs by Prussian blue staining and transmission electron microscopy. The relaxation rates of labeled cells in MRI were 4.4 and 4.2 times higher than those of the unlabeled cells. Hypointensity area was found by MRI three weeks after transplantation. Many hBMSCs and new vessels were found in the transplantation zone by pathological and immunofluorescence methods. Ferumoxide-PLL can effectively label hBMSCs and thus increase its contrast in MRI results. The cells can survive in the brains of cynomolgus monkeys. The labeled hBMSCs can be traced in vivo by MRI.

Tracking and tracing of participants in two large cancer screening trials.

Science.gov (United States)

Marcus, Pamela M; Childs, Jeffery; Gahagan, Betsy; Gren, Lisa H

2012-07-01

Many clinical trials rely on participant report to first learn about study events. It is therefore important to have current contact information and the ability to locate participants should information become outdated. The Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial (PLCO) and the Lung Screening Study (LSS) component of the National Lung Screening Trial, two large randomized cancer screening trials, enrolled almost 190,000 participants on whom annual contact was necessary. Ten screening centers participated in both trials. Centers developed methods to track participants and trace them when necessary. We describe the methods used to keep track of participants and trace them when lost, and the extent to which each method was used. Screening center coordinators were asked, using a self-administered paper questionnaire, to rate the extent to which specific tracking and tracing methods were used. Many methods were used by the screening centers, including telephone calls, mail, and internet searches. The most extensively used methods involved telephoning the participant on his or her home or cell phone, or telephoning a person identified by the participant as someone who would know about the participant's whereabouts. Internet searches were used extensively as well; these included searches on names, reverse-lookup searches (on addresses or telephone numbers) and searches of the Social Security Death Index. Over time, the percentage of participants requiring tracing decreased. Telephone communication and internet services were useful in keeping track of PLCO and LSS participants and tracing them when contact information was no longer valid. Published by Elsevier Inc.

Role of nuclear analytical probe techniques in biological trace element research

International Nuclear Information System (INIS)

Jones, K.W.; Pounds, J.G.

1985-01-01

Many biomedical experiments require the qualitative and quantitative localization of trace elements with high sensitivity and good spatial resolution. The feasibility of measuring the chemical form of the elements, the time course of trace elements metabolism, and of conducting experiments in living biological systems are also important requirements for biological trace element research. Nuclear analytical techniques that employ ion or photon beams have grown in importance in the past decade and have led to several new experimental approaches. Some of the important features of these methods are reviewed here along with their role in trace element research, and examples of their use are given to illustrate potential for new research directions. It is emphasized that the effective application of these methods necessitates a closely integrated multidisciplinary scientific team. 21 refs., 4 figs., 1 tab

Development of a selective and sensitive flotation method for determination of trace amounts of cobalt, nickel, copper and iron in environmental samples.

Science.gov (United States)

Karimi, H; Ghaedi, M; Shokrollahi, A; Rajabi, H R; Soylak, M; Karami, B

2008-02-28

A simple, selective and rapid flotation method for the separation-preconcentration of trace amounts of cobalt, nickel, iron and copper ions using phenyl 2-pyridyl ketone oxime (PPKO) has been developed prior to their flame atomic absorption spectrometric determinations. The influence of pH, amount of PPKO as collector, type and amount of eluting agent, type and amount of surfactant as floating agent and ionic strength was evaluated on the recoveries of analytes. The influences of the concomitant ions on the recoveries of the analyte ions were also examined. The enrichment factor was 93. The detection limits based on 3 sigma for Cu, Ni, Co and Fe were 0.7, 0.7, 0.8, and 0.7 ng mL(-1), respectively. The method has been successfully applied for determination of trace amounts of ions in various real samples.

Development of a selective and sensitive flotation method for determination of trace amounts of cobalt, nickel, copper and iron in environmental samples

International Nuclear Information System (INIS)

Karimi, H.; Ghaedi, M.; Shokrollahi, A.; Rajabi, H.R.; Soylak, M.; Karami, B.

2008-01-01

A simple, selective and rapid flotation method for the separation-preconcentration of trace amounts of cobalt, nickel, iron and copper ions using phenyl 2-pyridyl ketone oxime (PPKO) has been developed prior to their flame atomic absorption spectrometric determinations. The influence of pH, amount of PPKO as collector, type and amount of eluting agent, type and amount of surfactant as floating agent and ionic strength was evaluated on the recoveries of analytes. The influences of the concomitant ions on the recoveries of the analyte ions were also examined. The enrichment factor was 93. The detection limits based on 3 sigma for Cu, Ni, Co and Fe were 0.7, 0.7, 0.8, and 0.7 ng mL -1 , respectively. The method has been successfully applied for determination of trace amounts of ions in various real samples

Rapid and efficient method to extract metagenomic DNA from estuarine sediments.

Science.gov (United States)

Shamim, Kashif; Sharma, Jaya; Dubey, Santosh Kumar

2017-07-01

Metagenomic DNA from sediments of selective estuaries of Goa, India was extracted using a simple, fast, efficient and environment friendly method. The recovery of pure metagenomic DNA from our method was significantly high as compared to other well-known methods since the concentration of recovered metagenomic DNA ranged from 1185.1 to 4579.7 µg/g of sediment. The purity of metagenomic DNA was also considerably high as the ratio of absorbance at 260 and 280 nm ranged from 1.88 to 1.94. Therefore, the recovered metagenomic DNA was directly used to perform various molecular biology experiments viz. restriction digestion, PCR amplification, cloning and metagenomic library construction. This clearly proved that our protocol for metagenomic DNA extraction using silica gel efficiently removed the contaminants and prevented shearing of the metagenomic DNA. Thus, this modified method can be used to recover pure metagenomic DNA from various estuarine sediments in a rapid, efficient and eco-friendly manner.

Method for Determining Optimal Residential Energy Efficiency Retrofit Packages

Energy Technology Data Exchange (ETDEWEB)

Polly, B.; Gestwick, M.; Bianchi, M.; Anderson, R.; Horowitz, S.; Christensen, C.; Judkoff, R.

2011-04-01

Businesses, government agencies, consumers, policy makers, and utilities currently have limited access to occupant-, building-, and location-specific recommendations for optimal energy retrofit packages, as defined by estimated costs and energy savings. This report describes an analysis method for determining optimal residential energy efficiency retrofit packages and, as an illustrative example, applies the analysis method to a 1960s-era home in eight U.S. cities covering a range of International Energy Conservation Code (IECC) climate regions. The method uses an optimization scheme that considers average energy use (determined from building energy simulations) and equivalent annual cost to recommend optimal retrofit packages specific to the building, occupants, and location. Energy savings and incremental costs are calculated relative to a minimum upgrade reference scenario, which accounts for efficiency upgrades that would occur in the absence of a retrofit because of equipment wear-out and replacement with current minimum standards.

An Efficient Simulation Method for Rare Events

KAUST Repository

Rached, Nadhir B.

2015-01-07

Estimating the probability that a sum of random variables (RVs) exceeds a given threshold is a well-known challenging problem. Closed-form expressions for the sum distribution do not generally exist, which has led to an increasing interest in simulation approaches. A crude Monte Carlo (MC) simulation is the standard technique for the estimation of this type of probability. However, this approach is computationally expensive, especially when dealing with rare events. Variance reduction techniques are alternative approaches that can improve the computational efficiency of naive MC simulations. We propose an Importance Sampling (IS) simulation technique based on the well-known hazard rate twisting approach, that presents the advantage of being asymptotically optimal for any arbitrary RVs. The wide scope of applicability of the proposed method is mainly due to our particular way of selecting the twisting parameter. It is worth observing that this interesting feature is rarely satisfied by variance reduction algorithms whose performances were only proven under some restrictive assumptions. It comes along with a good efficiency, illustrated by some selected simulation results comparing the performance of our method with that of an algorithm based on a conditional MC technique.

An Efficient Simulation Method for Rare Events

KAUST Repository

Rached, Nadhir B.; Benkhelifa, Fatma; Kammoun, Abla; Alouini, Mohamed-Slim; Tempone, Raul

2015-01-01

Estimating the probability that a sum of random variables (RVs) exceeds a given threshold is a well-known challenging problem. Closed-form expressions for the sum distribution do not generally exist, which has led to an increasing interest in simulation approaches. A crude Monte Carlo (MC) simulation is the standard technique for the estimation of this type of probability. However, this approach is computationally expensive, especially when dealing with rare events. Variance reduction techniques are alternative approaches that can improve the computational efficiency of naive MC simulations. We propose an Importance Sampling (IS) simulation technique based on the well-known hazard rate twisting approach, that presents the advantage of being asymptotically optimal for any arbitrary RVs. The wide scope of applicability of the proposed method is mainly due to our particular way of selecting the twisting parameter. It is worth observing that this interesting feature is rarely satisfied by variance reduction algorithms whose performances were only proven under some restrictive assumptions. It comes along with a good efficiency, illustrated by some selected simulation results comparing the performance of our method with that of an algorithm based on a conditional MC technique.

Efficiency analysis of hydrogen production methods from biomass

NARCIS (Netherlands)

Ptasinski, K.J.

2008-01-01

Abstract: Hydrogen is considered as a universal energy carrier for the future, and biomass has the potential to become a sustainable source of hydrogen. This article presents an efficiency analysis of hydrogen production processes from a variety of biomass feedstocks by a thermochemical method –

TiO{sub 2} assisted photo-oxidation of wastewater prior to voltammetric determination of trace metals: Eco-friendly alternative to traditional digestion methods

Energy Technology Data Exchange (ETDEWEB)

Lejbt, Beata; Ospina-Alvarez, Natalia; Miecznikowski, Krzysztof, E-mail: kmiecz@chem.uw.edu.pl; Krasnodębska-Ostręga, Beata, E-mail: bekras@chem.uw.edu.pl

2016-12-01

Highlights: • Cheap and eco-friendly method using anatase-assisted photodecomposition to pre-treat wastewater samples prior to trace metal analysis. • Addition of polyvinylidene fluoride did not affect the efficiency of organic matter decomposition. • TiO{sub 2} assisted photo-oxidation procedure is equally effective than ICP MS determination after UV assisted digestion with H{sub 2}O{sub 2} addition. - Abstract: Voltammetry is a sensitive method for metal determination and one alternative to ICP MS, but its limitation is the influence of the organic matrix on the measurements. To avoid those interferences, wet digestion with H{sub 2}O{sub 2} accelerated with UV irradiation is applied and evaporation of excess of reagents is required. In this study, photolytic oxidation in quartz tubes with anatase was carried out, using as object of study wastewater samples with high amount of organic matter. Cadmium and lead determination was carried out in order to test metal recoveries. Lead recoveries reached c.a 85% for UV digestion with hydrogen peroxide, 98% for digestion with anatase immobilized with polyvinylidene fluoride (N-metylo-2-pirolidon) and c.a 103% for digestion with immobilized anatase (anatase in gum). The results obtained showed the usefulness of TiO{sub 2} layer as an oxidation medium. An easy, cheap and eco-friendly digestion method of surfactants without any reagent has been developed, with equal sensitivity but and the same detection limit of traditional digestion methods.

Efficient formalism for treating tapered structures using the Fourier modal method

DEFF Research Database (Denmark)

Østerkryger, Andreas Dyhl; Gregersen, Niels

2016-01-01

We investigate the development of the mode occupations in tapered structures using the Fourier modal method. In order to use the Fourier modal method, tapered structures are divided into layers of uniform refractive index in the propagation direction and the optical modes are found within each...... layer. This is not very efficient and in this proceeding we take the first steps towards a more efficient formalism for treating tapered structures using the Fourier modal method. We show that the coupling coefficients through the structure are slowly varying and that only the first few modes...

Use of mosses as biomonitors of atmospheric deposition of trace elements

International Nuclear Information System (INIS)

Steinnes, E.

2000-01-01

Some basic facts about the use of mosses as biomonitors of atmospheric trace element deposition are reviewed, and advantages and limitations of this approach are discussed, largely on the basis of experience from regular use of this technique in Norway over the last 20 years. Topics discussed include different versions of the moss technique, mechanisms and efficiencies of trace element uptake, conversion of concentrations in moss to bulk deposition rates, and contribution from sources other than air pollution to the elemental composition of different elements. Suggestions are presented for further work in order to extend the use of mosses as biomonitors. (author)

Fate of trace element haps when applying mercury control technologies

Energy Technology Data Exchange (ETDEWEB)

Nyberg, Carolyn M.; Thompson, Jeffrey S.; Zhuang, Ye; Pavlish, John H. [University of North Dakota Energy and Environmental Research Center 15 North 23rd Street, Stop 9018, Grand Forks, North Dakota 58202-9018 (United States); Brickett, Lynn; Pletcher, Sara [U.S. Department of Energy National Energy Technology Laboratory 626 Cochrans Mill Road, PO Box 10940, MS 922-273C, Pittsburgh, PA 15236-0940 (United States)

2009-11-15

During the past several years, and particularly since the Clean Air Mercury Rule (CAMR) was promulgated in June of 2005, the electric utility industry, product vendors, and the research community have been working diligently to develop and test Hg control strategies for a variety of coal types and plant configurations. Some of these strategies include sorbent injection and chemical additives designed to increase mercury capture efficiency in particulate control devices. These strategies have the potential to impact the fate of other inorganic hazardous air pollutants (HAPs), which typically include As, Be, Cd, Cr, Co, Mn, Ni, Pb, Se, and Sb. To evaluate this impact, flue gas samples using EPA Method 29, along with representative coal and ash samples, were collected during recent pilot-scale and field test projects that were evaluating Hg control technologies. These test programs included a range of fuel types with varying trace element concentrations, along with different combustion systems and particulate control devices. The results show that the majority of the trace element HAPs are associated with the particulate matter in the flue gas, except for Se. However, for five of the six projects, Se partitioning was shifted to the particulate phase and total emissions reduced when Hg control technologies were applied. (author)

Fast and sensitive trace analysis of malachite green using a surface-enhanced Raman microfluidic sensor.

Science.gov (United States)

Lee, Sangyeop; Choi, Junghyun; Chen, Lingxin; Park, Byungchoon; Kyong, Jin Burm; Seong, Gi Hun; Choo, Jaebum; Lee, Yeonjung; Shin, Kyung-Hoon; Lee, Eun Kyu; Joo, Sang-Woo; Lee, Kyeong-Hee

2007-05-08

A rapid and highly sensitive trace analysis technique for determining malachite green (MG) in a polydimethylsiloxane (PDMS) microfluidic sensor was investigated using surface-enhanced Raman spectroscopy (SERS). A zigzag-shaped PDMS microfluidic channel was fabricated for efficient mixing between MG analytes and aggregated silver colloids. Under the optimal condition of flow velocity, MG molecules were effectively adsorbed onto silver nanoparticles while flowing along the upper and lower zigzag-shaped PDMS channel. A quantitative analysis of MG was performed based on the measured peak height at 1615 cm(-1) in its SERS spectrum. The limit of detection, using the SERS microfluidic sensor, was found to be below the 1-2 ppb level and this low detection limit is comparable to the result of the LC-Mass detection method. In the present study, we introduce a new conceptual detection technology, using a SERS microfluidic sensor, for the highly sensitive trace analysis of MG in water.

Efficient point cloud data processing in shipbuilding: Reformative component extraction method and registration method

Directory of Open Access Journals (Sweden)

Jingyu Sun

2014-07-01

Full Text Available To survive in the current shipbuilding industry, it is of vital importance for shipyards to have the ship components’ accuracy evaluated efficiently during most of the manufacturing steps. Evaluating components’ accuracy by comparing each component’s point cloud data scanned by laser scanners and the ship’s design data formatted in CAD cannot be processed efficiently when (1 extract components from point cloud data include irregular obstacles endogenously, or when (2 registration of the two data sets have no clear direction setting. This paper presents reformative point cloud data processing methods to solve these problems. K-d tree construction of the point cloud data fastens a neighbor searching of each point. Region growing method performed on the neighbor points of the seed point extracts the continuous part of the component, while curved surface fitting and B-spline curved line fitting at the edge of the continuous part recognize the neighbor domains of the same component divided by obstacles’ shadows. The ICP (Iterative Closest Point algorithm conducts a registration of the two sets of data after the proper registration’s direction is decided by principal component analysis. By experiments conducted at the shipyard, 200 curved shell plates are extracted from the scanned point cloud data, and registrations are conducted between them and the designed CAD data using the proposed methods for an accuracy evaluation. Results show that the methods proposed in this paper support the accuracy evaluation targeted point cloud data processing efficiently in practice.

Boundary multi-trace deformations and Opens in AdS/CFT correspondence

International Nuclear Information System (INIS)

Petkou, Anastasios C.

2002-01-01

We argue that multi-trace deformations of the boundary CFT in AdS/CFT correspondence can arise through the OPE of single-trace operators. We work out the example of a scalar field in AdS 5 with cubic self interaction. By an appropriate reparametrization of the boundary data we are able to deform the boundary CFT by a marginal operator that couples to the conformal anomaly. Our method can be used in the analysis of multi-trace deformations in N=4 SYM where the OPEs of various single-trace operators are known. (author)

SYSTEMATIC ERROR REDUCTION: NON-TILTED REFERENCE BEAM METHOD FOR LONG TRACE PROFILER

International Nuclear Information System (INIS)

QIAN, S.; QIAN, K.; HONG, Y.; SENG, L.; HO, T.; TAKACS, P.

2007-01-01

Systematic error in the Long Trace Profiler (LTP) has become the major error source as measurement accuracy enters the nanoradian and nanometer regime. Great efforts have been made to reduce the systematic error at a number of synchrotron radiation laboratories around the world. Generally, the LTP reference beam has to be tilted away from the optical axis in order to avoid fringe overlap between the sample and reference beams. However, a tilted reference beam will result in considerable systematic error due to optical system imperfections, which is difficult to correct. Six methods of implementing a non-tilted reference beam in the LTP are introduced: (1) application of an external precision angle device to measure and remove slide pitch error without a reference beam, (2) independent slide pitch test by use of not tilted reference beam, (3) non-tilted reference test combined with tilted sample, (4) penta-prism scanning mode without a reference beam correction, (5) non-tilted reference using a second optical head, and (6) alternate switching of data acquisition between the sample and reference beams. With a non-tilted reference method, the measurement accuracy can be improved significantly. Some measurement results are presented. Systematic error in the sample beam arm is not addressed in this paper and should be treated separately

Method for Determining Volumetric Efficiency and Its Experimental Validation

Directory of Open Access Journals (Sweden)

Ambrozik Andrzej

2017-12-01

Full Text Available Modern means of transport are basically powered by piston internal combustion engines. Increasingly rigorous demands are placed on IC engines in order to minimise the detrimental impact they have on the natural environment. That stimulates the development of research on piston internal combustion engines. The research involves experimental and theoretical investigations carried out using computer technologies. While being filled, the cylinder is considered to be an open thermodynamic system, in which non-stationary processes occur. To make calculations of thermodynamic parameters of the engine operating cycle, based on the comparison of cycles, it is necessary to know the mean constant value of cylinder pressure throughout this process. Because of the character of in-cylinder pressure pattern and difficulties in pressure experimental determination, in the present paper, a novel method for the determination of this quantity was presented. In the new approach, the iteration method was used. In the method developed for determining the volumetric efficiency, the following equations were employed: the law of conservation of the amount of substance, the first law of thermodynamics for open system, dependences for changes in the cylinder volume vs. the crankshaft rotation angle, and the state equation. The results of calculations performed with this method were validated by means of experimental investigations carried out for a selected engine at the engine test bench. A satisfactory congruence of computational and experimental results as regards determining the volumetric efficiency was obtained. The method for determining the volumetric efficiency presented in the paper can be used to investigate the processes taking place in the cylinder of an IC engine.

Tracing contacts of TB patients in Malaysia: costs and practicality.

Science.gov (United States)

Atif, Muhammad; Sulaiman, Syed Azhar Syed; Shafie, Asrul Akmal; Ali, Irfhan; Asif, Muhammad

2012-01-01

Tuberculin skin testing (TST) and chest X-ray are the conventional methods used for tracing suspected tuberculosis (TB) patients. The purpose of the study was to calculate the cost incurred by Penang General Hospital on performing one contact tracing procedure using an activity based costing approach. Contact tracing records (including the demographic profile of contacts and outcome of the contact tracing procedure) from March 2010 until February 2011 were retrospectively obtained from the TB contact tracing record book. The human resource cost was calculated by multiplying the mean time spent (in minutes) by employees doing a specific activity by their per-minute salaries. The costs of consumables, Purified Protein Derivative vials and clinical equipment were obtained from the procurement section of the Pharmacy and Radiology Departments. The cost of the building was calculated by multiplying the area of space used by the facility with the unit cost of the public building department. Straight-line deprecation with a discount rate of 3% was assumed for the calculation of equivalent annual costs for the building and machines. Out of 1024 contact tracing procedures, TST was positive (≥10 mm) in 38 suspects. However, chemoprophylaxis was started in none. Yield of contact tracing (active tuberculosis) was as low as 0.5%. The total unit cost of chest X-ray and TST was MYR 9.23 (2.90 USD) & MYR 11.80 (USD 3.70), respectively. The total cost incurred on a single contact tracing procedure was MYR 21.03 (USD 6.60). Our findings suggest that the yield of contact tracing was very low which may be attributed to an inappropriate prioritization process. TST may be replaced with more accurate and specific methods (interferon gamma release assay) in highly prioritized contacts; or TST-positive contacts should be administered 6H therapy (provided that the chest radiography excludes TB) in accordance with standard protocols. The unit cost of contact tracing can be significantly

Study of trace elements in milk by nuclear analytical techniques

Energy Technology Data Exchange (ETDEWEB)

Gharib, A.; Rahimi, H.; Peyrovan, H.; Raofei, H.N.J.; Taherpour, H. (Atomic Energy Organization of Iran, Teheran. Nuclear Research Centre)

This work is part of a project with the IAEA, in a coordinated programme on ''trace elements in Human Nutrition and Bio-Environmental Systems'' to evaluate their nutritional requirements, interrelations and the role of trace elements in health, metabolism etc. Cow's milk is regarded as one of the most important and nutritious foodstuffs consumed by people. Hence, as a first step, an elemental analysis for milk was carried out for this purpose so a few samples of pasteurized milk and local samples were investigated for essential and toxic trace elements. The secondary aim of this project was the assessment of various analytical techniques involved. However, in the present work, the methods involved were AAS, PIXE and NAA. The latter method applied, both instrumentally and radiochemically. Although the results pertaining to the various methods employed are not in good agreement, there is however, some justification to clarify this internal inconsistency. The precision for NAA and AAS allows greater degree of acceptance respectively. Although PIXE is very fast and rather routine, the technique of trace element analysis needs certain adaptations and developments.

Determination of lead element trace in some Syrian cigarettes and Its mixtures using voltammetric method on HMDE

International Nuclear Information System (INIS)

Nasser, H.; Kabass, H.

2010-01-01

This study aims for estimating of trace for these elements in various brands of Syrian Cigarettes and its mixtures, by using voltammetric method (HMDE) hanging mercury drop elec trod. This method is first used to determined Syrian Cigarettes brand and its mixtures, during this study it was found that we can use it easily with low commission, high sensitivity and accurate results comparing with others studies. We prepare the samples by using reference methods. The samples were collected during two times in one year from the same kinds of samples. We noticed that the high concentrations was (3.795μg/g) in Gitanes samples, and the low concentrations in shame samples was (0.37 μg/g). This study refers that there is different concentrations of lead element in this samples.(author)

Trace elemental analysis of carcinoma kidney and stomach by PIXE method

International Nuclear Information System (INIS)

Reddy, S. Bhuloka; John Charles, M.; Naga Raju, G.J.; Vijayan, V.; Seetharami Reddy, B.; Ravi Kumar, M.; Sundareswar, B.

2003-01-01

Trace elemental analysis was carried out in the biological samples of carcinoma kidney and stomach using particle induced X-ray emission technique. A 2 MeV proton beam was employed to excite the samples. From the present results, the levels of elements K, Ca, Fe, Ni and Se are lower and those of the elements Ti, Co, Zn, As and Cd are higher in the cancer tissue of kidney than those observed in the normal tissue. In the case of stomach, the concentrations of elements Cl, K, Ca, Ti, Mn, Fe, Co, Cu and Zn are lower while concentrations of elements Cr, Ni, As and Br are higher in the cancer tissue of stomach than those observed in the normal tissue. The observed deficiency or excess of certain elements is correlated to carcinogenesis of that organ. The present results of carcinoma stomach support the previous observations that nickel and chromium are carcinogenic agents. The low levels of selenium observed in the carcinoma tissue of kidney and the low levels of manganese observed in the carcinoma tissue of stomach support the view that selenium and manganese inhibit the growth of cancer in kidney and stomach respectively. The observed high levels of zinc in the cancer tissue of kidney suggest that zinc is involved in the tumor growth and development of neoplastic transformation in kidney while the observed low levels of zinc in the carcinoma tissue of stomach suggest that zinc inhibits the growth of cancer in this organ. For correctly assessing the role played by the trace elements in initiating, promoting or inhibiting cancer in various organs, there is a need for acquisition of more data by trace elemental analysis from several investigations of this type undertaken in different regions

Accelerator based nuclear analytical methods for trace element studies in materials- calcified tissues

International Nuclear Information System (INIS)

Chaudhri, M. Anwar

2006-01-01

Full text: Various nuclear analytical methods have been developed and applied to determine the elemental composition of calcified tissues (teeth and bones). Fluorine was determined by prompt gamma activation analysis through the 19 F(p,αγ) 16 O reaction. Carbon was measured by activation analysis with He-3 ions, and the technique of Proton-Induced X-ray Emission (PIXE) was applied to simultaneously determine Ca, P, and trace elements in well-documented teeth. Dental hard tissues: enamel, dentine, cementum, and their junctions, as well as different parts of the same tissue, were examined separately. Furthermore, using a Proton Microprobe, we measured the surface distribution of F and other elements on and around carious lesions on the enamel. The depth profiles of F, and other elements, were also measured right up to the amelodentin junction. (author)

An efficient Korringa-Kohn-Rostoker method for ''complex'' lattices

International Nuclear Information System (INIS)

Yussouff, M.; Zeller, R.

1980-10-01

We present a modification of the exact KKR-band structure method which uses (a) a new energy expansion for structure constants and (b) only the reciprocal lattice summation. It is quite efficient and particularly useful for 'complex' lattices. The band structure of hexagonal-close-packed Beryllium at symmetry points is presented as an example of this method. (author)

Projector Method: theory and examples

International Nuclear Information System (INIS)

Dahl, E.D.

1985-01-01

The Projector Method technique for numerically analyzing lattice gauge theories was developed to take advantage of certain simplifying features of gauge theory models. Starting from a very general notion of what the Projector Method is, the techniques are applied to several model problems. After these examples have traced the development of the actual algorithm from the general principles of the Projector Method, a direct comparison between the Projector and the Euclidean Monte Carlo is made, followed by a discussion of the application to Periodic Quantum Electrodynamics in two and three spatial dimensions. Some methods for improving the efficiency of the Projector in various circumstances are outlined. 10 refs., 7 figs

A Cost-Effective Transparency-Based Digital Imaging for Efficient and Accurate Wound Area Measurement

Science.gov (United States)

Li, Pei-Nan; Li, Hong; Wu, Mo-Li; Wang, Shou-Yu; Kong, Qing-You; Zhang, Zhen; Sun, Yuan; Liu, Jia; Lv, De-Cheng

2012-01-01

Wound measurement is an objective and direct way to trace the course of wound healing and to evaluate therapeutic efficacy. Nevertheless, the accuracy and efficiency of the current measurement methods need to be improved. Taking the advantages of reliability of transparency tracing and the accuracy of computer-aided digital imaging, a transparency-based digital imaging approach is established, by which data from 340 wound tracing were collected from 6 experimental groups (8 rats/group) at 8 experimental time points (Day 1, 3, 5, 7, 10, 12, 14 and 16) and orderly archived onto a transparency model sheet. This sheet was scanned and its image was saved in JPG form. Since a set of standard area units from 1 mm2 to 1 cm2 was integrated into the sheet, the tracing areas in JPG image were measured directly, using the “Magnetic lasso tool” in Adobe Photoshop program. The pixel values/PVs of individual outlined regions were obtained and recorded in an average speed of 27 second/region. All PV data were saved in an excel form and their corresponding areas were calculated simultaneously by the formula of Y (PV of the outlined region)/X (PV of standard area unit) × Z (area of standard unit). It took a researcher less than 3 hours to finish area calculation of 340 regions. In contrast, over 3 hours were expended by three skillful researchers to accomplish the above work with traditional transparency-based method. Moreover, unlike the results obtained traditionally, little variation was found among the data calculated by different persons and the standard area units in different sizes and shapes. Given its accurate, reproductive and efficient properties, this transparency-based digital imaging approach would be of significant values in basic wound healing research and clinical practice. PMID:22666449

F--Ray: A new algorithm for efficient transport of ionizing radiation

Science.gov (United States)

Mao, Yi; Zhang, J.; Wandelt, B. D.; Shapiro, P. R.; Iliev, I. T.

2014-04-01

We present a new algorithm for the 3D transport of ionizing radiation, called F2-Ray (Fast Fourier Ray-tracing method). The transfer of ionizing radiation with long mean free path in diffuse intergalactic gas poses a special challenge to standard numerical methods which transport the radiation in position space. Standard methods usually trace each individual ray until it is fully absorbed by the intervening gas. If the mean free path is long, the computational cost and memory load are likely to be prohibitive. We have developed an algorithm that overcomes these limitations and is, therefore, significantly more efficient. The method calculates the transfer of radiation collectively, using the Fast Fourier Transform to convert radiation between position and Fourier spaces, so the computational cost will not increase with the number of ionizing sources. The method also automatically combines parallel rays with the same frequency at the same grid cell, thereby minimizing the memory requirement. The method is explicitly photon-conserving, i.e. the depletion of ionizing photons is guaranteed to equal the photoionizations they caused, and explicitly obeys the periodic boundary condition, i.e. the escape of ionizing photons from one side of a simulation volume is guaranteed to be compensated by emitting the same amount of photons into the volume through the opposite side. Together, these features make it possible to numerically simulate the transfer of ionizing photons more efficiently than previous methods. Since ionizing radiation such as the X-ray is responsible for heating the intergalactic gas when first stars and quasars form at high redshifts, our method can be applied to simulate thermal distribution, in addition to cosmic reionization, in three-dimensional inhomogeneous cosmological density field.

Efficient generalized Golub-Kahan based methods for dynamic inverse problems

Science.gov (United States)

Chung, Julianne; Saibaba, Arvind K.; Brown, Matthew; Westman, Erik

2018-02-01

We consider efficient methods for computing solutions to and estimating uncertainties in dynamic inverse problems, where the parameters of interest may change during the measurement procedure. Compared to static inverse problems, incorporating prior information in both space and time in a Bayesian framework can become computationally intensive, in part, due to the large number of unknown parameters. In these problems, explicit computation of the square root and/or inverse of the prior covariance matrix is not possible, so we consider efficient, iterative, matrix-free methods based on the generalized Golub-Kahan bidiagonalization that allow automatic regularization parameter and variance estimation. We demonstrate that these methods for dynamic inversion can be more flexible than standard methods and develop efficient implementations that can exploit structure in the prior, as well as possible structure in the forward model. Numerical examples from photoacoustic tomography, space-time deblurring, and passive seismic tomography demonstrate the range of applicability and effectiveness of the described approaches. Specifically, in passive seismic tomography, we demonstrate our approach on both synthetic and real data. To demonstrate the scalability of our algorithm, we solve a dynamic inverse problem with approximately 43 000 measurements and 7.8 million unknowns in under 40 s on a standard desktop.

Chapter 20: Data Center IT Efficiency Measures Evaluation Protocol. The Uniform Methods Project: Methods for Determining Energy Efficiency Savings for Specific Measures

Energy Technology Data Exchange (ETDEWEB)

Kurnik, Charles W [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Huang, Robert [The Cadmus Group, Portland, OR (United States); Masanet, Eric [Northwestern Univ., Evanston, IL (United States)

2017-11-02

This chapter focuses on IT measures in the data center and examines the techniques and analysis methods used to verify savings that result from improving the efficiency of two specific pieces of IT equipment: servers and data storage.

Application of the EXtrapolated Efficiency Method (EXEM) to infer the gamma-cascade detection efficiency in the actinide region

Energy Technology Data Exchange (ETDEWEB)

Ducasse, Q. [CENBG, CNRS/IN2P3-Université de Bordeaux, Chemin du Solarium B.P. 120, 33175 Gradignan (France); CEA-Cadarache, DEN/DER/SPRC/LEPh, 13108 Saint Paul lez Durance (France); Jurado, B., E-mail: jurado@cenbg.in2p3.fr [CENBG, CNRS/IN2P3-Université de Bordeaux, Chemin du Solarium B.P. 120, 33175 Gradignan (France); Mathieu, L.; Marini, P. [CENBG, CNRS/IN2P3-Université de Bordeaux, Chemin du Solarium B.P. 120, 33175 Gradignan (France); Morillon, B. [CEA DAM DIF, 91297 Arpajon (France); Aiche, M.; Tsekhanovich, I. [CENBG, CNRS/IN2P3-Université de Bordeaux, Chemin du Solarium B.P. 120, 33175 Gradignan (France)

2016-08-01

The study of transfer-induced gamma-decay probabilities is very useful for understanding the surrogate-reaction method and, more generally, for constraining statistical-model calculations. One of the main difficulties in the measurement of gamma-decay probabilities is the determination of the gamma-cascade detection efficiency. In Boutoux et al. (2013) [10] we developed the EXtrapolated Efficiency Method (EXEM), a new method to measure this quantity. In this work, we have applied, for the first time, the EXEM to infer the gamma-cascade detection efficiency in the actinide region. In particular, we have considered the {sup 238}U(d,p){sup 239}U and {sup 238}U({sup 3}He,d){sup 239}Np reactions. We have performed Hauser–Feshbach calculations to interpret our results and to verify the hypothesis on which the EXEM is based. The determination of fission and gamma-decay probabilities of {sup 239}Np below the neutron separation energy allowed us to validate the EXEM.

Application of the EXtrapolated Efficiency Method (EXEM) to infer the gamma-cascade detection efficiency in the actinide region

International Nuclear Information System (INIS)

Ducasse, Q.; Jurado, B.; Mathieu, L.; Marini, P.; Morillon, B.; Aiche, M.; Tsekhanovich, I.

2016-01-01

The study of transfer-induced gamma-decay probabilities is very useful for understanding the surrogate-reaction method and, more generally, for constraining statistical-model calculations. One of the main difficulties in the measurement of gamma-decay probabilities is the determination of the gamma-cascade detection efficiency. In Boutoux et al. (2013) [10] we developed the EXtrapolated Efficiency Method (EXEM), a new method to measure this quantity. In this work, we have applied, for the first time, the EXEM to infer the gamma-cascade detection efficiency in the actinide region. In particular, we have considered the "2"3"8U(d,p)"2"3"9U and "2"3"8U("3He,d)"2"3"9Np reactions. We have performed Hauser–Feshbach calculations to interpret our results and to verify the hypothesis on which the EXEM is based. The determination of fission and gamma-decay probabilities of "2"3"9Np below the neutron separation energy allowed us to validate the EXEM.

The study of trace elements in milk by nuclear analytical techniques

International Nuclear Information System (INIS)

Gharib, A.; Rahimi, H.; Peyrovan, H.; Raofei, H.N.J.; Taherpour, H.

1983-01-01

This work is part of a project with the IAEA, in a coordinated programme on ''Trace Elements in Human Nutrition and Bio-Environmental Systems'' to evaluate their nutritional requirements, interrelations and the role of Trace Elements in health, metabolism etc. Cow's milk being regarded as one of the most important and nutritious foodstuffs consumed by people. Hence as a first step, an elemental analysis for milk was carried out for this purpose so a few samples of pasteurized milk and local samples were investigated for essential and toxic trace elements. The secondary aim of this project was the assessment of various analytical techniques involved. However, in the present work, the methods involved were AAS, PIXE and NAA. The latter method applied, both instrumentally and radiochemically. Although the results pertaining to the various methods employed are not in good agreement, there is however, some justification to clarify this internal inconsistency. The precision for NAA and AAS allows greater degree of acceptance respectively. Although PIXE is a very fast and rather a routine but the technique of trace element analysis needs certain adaptations and developments

Ray Tracing Study on Top ECCD Launch in KSTAR

Directory of Open Access Journals (Sweden)

Bae Young-soon

2017-01-01

Full Text Available The current drive efficiency of electron cyclotron (EC wave is typically low compared with other RF and neutral beam heating system in tokamak. It is known that EC current drive by outboard launch suffers from low current drive efficiency due to electron trapping. However, the heating and current drive by EC wave is being regarded as a strong candidate for DEMO reactor due to the simplicity of the launcher, none of its interaction with plasma, and no coupling issue at the plasma edge. Also, off-axis heating and current drive by EC wave plays an important role of steady state operation optimization. To enhance the current drive efficiency in DEMO-relevant operation condition having high density and high temperature, the top launch of EC wave is recently proposed in FNSF design [2]. In FNSF, a top launch makes use of a large toroidal component to the launch direction adjusting the vertical launch angle so that the rays propagate nearly parallel to the resonance layer increasing of Doppler shift with higher n||. The results shows a high dimensional efficiency for a broad ECCD profile peaked off axis. In KSTAR, the possibility of efficient off-axis ECCD using top launch is investigated using the ray tracing code, GENRAY [3] for the operating EC frequencies (105 GHz or 140 GHz, and 170 GHz. The high current drive efficiency is found by adjusting the toroidal magnetic field and the radial pivot position of the final launcher mirror for fundamental O-mode and second harmonic X-mode. A large Doppler shift is not quite sure in the typical plasma profile in KSTAR, but the simulation results show high current drive efficiency. This paper presents ray tracing results for many cases with the wave trajectories and damping of EC by scanning the launching angle for specific launcher pivot positions and toroidal magnetic field, and two equilibriums of the KSTAR.

An efficient and accurate method for calculating nonlinear diffraction beam fields

Energy Technology Data Exchange (ETDEWEB)

Jeong, Hyun Jo; Cho, Sung Jong; Nam, Ki Woong; Lee, Jang Hyun [Division of Mechanical and Automotive Engineering, Wonkwang University, Iksan (Korea, Republic of)

2016-04-15

This study develops an efficient and accurate method for calculating nonlinear diffraction beam fields propagating in fluids or solids. The Westervelt equation and quasilinear theory, from which the integral solutions for the fundamental and second harmonics can be obtained, are first considered. A computationally efficient method is then developed using a multi-Gaussian beam (MGB) model that easily separates the diffraction effects from the plane wave solution. The MGB models provide accurate beam fields when compared with the integral solutions for a number of transmitter-receiver geometries. These models can also serve as fast, powerful modeling tools for many nonlinear acoustics applications, especially in making diffraction corrections for the nonlinearity parameter determination, because of their computational efficiency and accuracy.

A new method to radiolabel fulvic acids with tritium for the purpose of tracing organic matter transport at low concentrations

International Nuclear Information System (INIS)

Tinnacher, R.M.; Honeyman, B.D.; Leenheer, J.A.

2005-01-01

Full text of publication follows: It is increasingly evident that reactive transport models for radionuclides need to include the effects of natural organic ligands, such as bacterial exudates and humic and fulvic acids. Understanding the role of such ligands in radionuclide transport requires an ability to track ligand concentrations in time and space with an analytical resolution similar to that of the target radionuclide. Unfortunately, for many systems of interest for radioactive waste disposal and performance assessment, organic ligand concentrations are quite low (e.g., mg C/ L or less). Radiolabeling organic ligands can provide a means of tracing such species at low levels and for relatively low cost. Currently-used labeling methods, however, show some limitations with respect to the chemical stability of the radiolabel, the ability to produce high label specific activities and method reproducibility. In the procedure that we will describe, fulvic acid is radiolabeled with tritium by its reduction with tritiated sodium borohydride (NaBH 4 ) at alkaline pH and slightly elevated temperatures. The reactant selectively reduces the carbonyl groups of aromatic and aliphatic ketones as well as quinones. This results in the formation of tritium-labeled secondary alcohols. After completion of the labeling reaction, aerobically unstable reduction products of quinones and aromatic ketones are re-oxidized under controlled experimental conditions during an aeration step. Labeling efficiency in terms of reduced reactive fulvic acid groups is in the range of 100 percent with equal weights of fulvic acid and NaBH 4 in the reaction solution. This yields specific activities on the order of 50 to 100 μCi / mg fulvic acid. A quasi-chemical model of the labeling process allows the accurate prediction of the labeling efficiency based on a simplified mass action expression for the labeling reaction and the mass balance equations for fulvic acid and sodium borohydride. Such a

Efficient parallel implicit methods for rotary-wing aerodynamics calculations

Science.gov (United States)

Wissink, Andrew M.

Euler/Navier-Stokes Computational Fluid Dynamics (CFD) methods are commonly used for prediction of the aerodynamics and aeroacoustics of modern rotary-wing aircraft. However, their widespread application to large complex problems is limited lack of adequate computing power. Parallel processing offers the potential for dramatic increases in computing power, but most conventional implicit solution methods are inefficient in parallel and new techniques must be adopted to realize its potential. This work proposes alternative implicit schemes for Euler/Navier-Stokes rotary-wing calculations which are robust and efficient in parallel. The first part of this work proposes an efficient parallelizable modification of the Lower Upper-Symmetric Gauss Seidel (LU-SGS) implicit operator used in the well-known Transonic Unsteady Rotor Navier Stokes (TURNS) code. The new hybrid LU-SGS scheme couples a point-relaxation approach of the Data Parallel-Lower Upper Relaxation (DP-LUR) algorithm for inter-processor communication with the Symmetric Gauss Seidel algorithm of LU-SGS for on-processor computations. With the modified operator, TURNS is implemented in parallel using Message Passing Interface (MPI) for communication. Numerical performance and parallel efficiency are evaluated on the IBM SP2 and Thinking Machines CM-5 multi-processors for a variety of steady-state and unsteady test cases. The hybrid LU-SGS scheme maintains the numerical performance of the original LU-SGS algorithm in all cases and shows a good degree of parallel efficiency. It experiences a higher degree of robustness than DP-LUR for third-order upwind solutions. The second part of this work examines use of Krylov subspace iterative solvers for the nonlinear CFD solutions. The hybrid LU-SGS scheme is used as a parallelizable preconditioner. Two iterative methods are tested, Generalized Minimum Residual (GMRES) and Orthogonal s-Step Generalized Conjugate Residual (OSGCR). The Newton method demonstrates good

Modified batch anaerobic digestion assay for testing efficiencies of trace metal additives to enhance methane production of energy crops.

Science.gov (United States)

Brulé, Mathieu; Bolduan, Rainer; Seidelt, Stephan; Schlagermann, Pascal; Bott, Armin

2013-01-01

Batch biochemical methane potential (BMP) assays to evaluate the methane yield of biogas substrates such as energy crops are usually carried out with undiluted inoculum. A BMP assay was performed on two energy crops (green cuttings and grass silage). Anaerobic digestion was performed both with and without supplementation of three commercial additives containing trace metals in liquid, solid or adsorbed form (on clay particles). In order to reveal positive effects of trace metal supplementation on the methane yield, besides undiluted inoculum, 3-fold and 10-fold dilutions of the inoculum were applied for substrate digestion. Diluted inoculum variants were supplemented with both mineral nutrients and pH-buffering substances to prevent a collapse of the digestion process. As expected, commercial additives had no effect on the digestion process performed with undiluted inoculum, while significant increases of methane production through trace element supplementation could be observed on the diluted variants. The effect of inoculum dilution may be twofold: (1) decrease in trace metal supplementation from the inoculum and (2) reduction in the initial number of bacterial cells. Bacteria require higher growth rates for substrate degradation and hence have higher trace element consumption. According to common knowledge of the biogas process, periods with volatile fatty acids accumulation and decreased pH may have occurred in the course ofanaerobic digestion. These effects may have led to inhibition, not only ofmethanogenes and acetogenes involved in the final phases of methane production, but also offibre-degrading bacterial strains involved in polymer hydrolysis. Further research is required to confirm this hypothesis.

Levels of trace elements in MWSS drinking water

International Nuclear Information System (INIS)

Andal, T.T.

1998-01-01

As a water supplier for the metropolis, vigilance over the water quality has not been taken for granted at the Metropolitan Waterworks and Sewerage System (MWSS). By the early 1980's, a control laboratory equipped with modern facilities had been set up to supplement the already existing control laboratory at Filter Plant II handling physical, chemical, bacteriological, biological and mineral analyses and examinations, efficiently. The new central laboratory is intended to monitor trace elements, organic constituents and other elements with health related impact so as to assure the consumers of a safe drinking water supply at all times. This presentation reviews the levels of trace element pollution in MWSS tap water, then and now, in justification of the rehabilitation projects along the distribution network, in the treatment plants and other pertinent innovations corresponding to budgeted capital outlays as invested by the system. (author)

Tracing the breeding farm of domesticated pig using feature selection (

Directory of Open Access Journals (Sweden)

Taehyung Kwon

2017-11-01

Full Text Available Objective Increasing food safety demands in the animal product market have created a need for a system to trace the food distribution process, from the manufacturer to the retailer, and genetic traceability is an effective method to trace the origin of animal products. In this study, we successfully achieved the farm tracing of 6,018 multi-breed pigs, using single nucleotide polymorphism (SNP markers strictly selected through least absolute shrinkage and selection operator (LASSO feature selection. Methods We performed farm tracing of domesticated pig (Sus scrofa from SNP markers and selected the most relevant features for accurate prediction. Considering multi-breed composition of our data, we performed feature selection using LASSO penalization on 4,002 SNPs that are shared between breeds, which also includes 179 SNPs with small between-breed difference. The 100 highest-scored features were extracted from iterative simulations and then evaluated using machine-leaning based classifiers. Results We selected 1,341 SNPs from over 45,000 SNPs through iterative LASSO feature selection, to minimize between-breed differences. We subsequently selected 100 highest-scored SNPs from iterative scoring, and observed high statistical measures in classification of breeding farms by cross-validation only using these SNPs. Conclusion The study represents a successful application of LASSO feature selection on multi-breed pig SNP data to trace the farm information, which provides a valuable method and possibility for further researches on genetic traceability.

Inorganic trace analysis by laser ionization mass spectrometry

International Nuclear Information System (INIS)

Becker, S.; Dietze, H.J.

1991-01-01

Among the different spectrometric techniques for trace analysis Laser Ionization Mass Spectrometry (LIMS) is well established as a trace analytic method with a wide coverage. In the LIMS the sample material is evaporated and ionized by means of a focused pulsed laser beam in a laser microplasma, which is formed in the spot area of the irradiated sample. All chemical elements in the sample materials are evaporated and ionized in the laser plasma. The formed ions are separated according to mass and energy by a time-of-flight, quadrupole or double focusing mass spectrometer. In this review the characteristics and analytical features, some recent developments, and applications of laser ionization mass spectrometry in inorganic trace analysis are described. (orig.)

Laser ionization mass spectrometry in inorganic trace analysis

International Nuclear Information System (INIS)

Becker, J.S.; Dietze, H.J.

1992-01-01

Among the different spectrometric techniques for trace analysis Laser Ionization Mass Spectrometry (LIMS) is well established as a trace analytical method. With the LIMS technique the sample material is evaporated and ionized by means of a focused pulsed laser in a laser microplasma, which is formed in the spot area of the irradiated sample. All chemical elements in the sample materials are evaporated and ionized in the laser plasma. The ions formed are separated according to their mass and energy by a time-of-flight, quadrupole or double focusing mass spectrometer. In this review the characteristics and analytical features, some recent developments and applications of laser ionization mass spectrometry in inorganic trace analysis are described. (orig.)

Combination of ray-tracing and the method of moments for electromagnetic radiation analysis using reduced meshes

Science.gov (United States)

Delgado, Carlos; Cátedra, Manuel Felipe

2018-05-01

This work presents a technique that allows a very noticeable relaxation of the computational requirements for full-wave electromagnetic simulations based on the Method of Moments. A ray-tracing analysis of the geometry is performed in order to extract the critical points with significant contributions. These points are then used to generate a reduced mesh, considering the regions of the geometry that surround each critical point and taking into account the electrical path followed from the source. The electromagnetic analysis of the reduced mesh produces very accurate results, requiring a fraction of the resources that the conventional analysis would utilize.

Study on SF6 trace experiment in Lianyungang Nuclear Power Plant

International Nuclear Information System (INIS)

Hu Erbang; Yan Jiangyu; Zhang Yongyi; Wen Lianzhong

2001-01-01

10 times SF 6 trace experiments were successfully performed in August 1997 on a very complex terrain of Lianyungang Nuclear Power Plant in order to obtain plume trajectory and diffusion parameters. SF 6 is released from the top of a tower of 100 m. The sample points are arranged not only on the sample lines but also on the areas near residences. About 50 samples are obtained in each SF 6 trace experiment. The samples of SF 6 are analysed by the GC-ECD method. The weather stability is 5 times C and D stabilities respectively if using P-G method or 10 times D stabilities if using ΔT-U method. A least-square method is adopted to obtain the diffusion parameters from diffusion equation. Meanwhile the effect on the diffusion parameters from sampling time is measured based on the above SF 6 trace experiment

Trace element removal from coal ash leachate by the 10-year-old construction wetland

Energy Technology Data Exchange (ETDEWEB)

Ye, Z.H.; Whiting, S.N.; Qian, J.H.; Lytle, C.M.; Lin, Z.-Q.; Terry, N. [University of California at Berkeley, Berkeley, CA (USA). Dept. of Plant and Microbial Biology

2001-10-01

The study investigated the ability of a 10-year old constructed wetland to treat metal-contaminated leachate emanating from a coal ash pile at the Widows Creek electric utility, Alabama (USA). The two vegetated cells, which were dominated by cattail (Typha latifolia L.) and soft rush (Juncus effusus L.), were very effective at removing Fe and Cd from the wastewater, but less efficient for Zn, S, B, and Mn. The concentrations were decreased by up to 99% for Fe, 91% for Cd, 63% for Zn, 61% for S, 58% for Mn, and 50% for B. Higher pH levels ({gt} 6) in standing water substantially improved the removing efficiency of the wetland for Mn only. The belowground tissues of both cattail and soft rush had high concentrations of all elements; only for Mn, however, did the concentration in the shoots exceed those in the belowground tissues. The concentrations of trace elements in fallen litter were higher than in the living shoots, but lower than in the belowground tissues. The trace element accumulation in the plants accounts for less than 2.5% of the annual loading of each trace element into the wetland. The sediments were the primary sinks for the elements removed from the wastewater. Except for Mn, the concentrations of trace elements in the upper layer (0-5 cm) of the sediment profile tended to be higher than the lower layers (5-10 and 10-15 cm). The conclusion was that constructed wetlands are still able to efficiently remove metals in the long term (i.e. {gt} 10 years after construction). 34 refs., 7 figs., 2 tabs.

Neural population-level memory traces in the mouse hippocampus.

Science.gov (United States)

Chen, Guifen; Wang, L Phillip; Tsien, Joe Z

2009-12-16

One of the fundamental goals in neurosciences is to elucidate the formation and retrieval of brain's associative memory traces in real-time. Here, we describe real-time neural ensemble transient dynamics in the mouse hippocampal CA1 region and demonstrate their relationships with behavioral performances during both learning and recall. We employed the classic trace fear conditioning paradigm involving a neutral tone followed by a mild foot-shock 20 seconds later. Our large-scale recording and decoding methods revealed that conditioned tone responses and tone-shock association patterns were not present in CA1 during the first pairing, but emerged quickly after multiple pairings. These encoding patterns showed increased immediate-replay, correlating tightly with increased immediate-freezing during learning. Moreover, during contextual recall, these patterns reappeared in tandem six-to-fourteen times per minute, again correlating tightly with behavioral recall. Upon traced tone recall, while various fear memories were retrieved, the shock traces exhibited a unique recall-peak around the 20-second trace interval, further signifying the memory of time for the expected shock. Therefore, our study has revealed various real-time associative memory traces during learning and recall in CA1, and demonstrates that real-time memory traces can be decoded on a moment-to-moment basis over any single trial.

Neural population-level memory traces in the mouse hippocampus.

Directory of Open Access Journals (Sweden)

Guifen Chen

2009-12-01

Full Text Available One of the fundamental goals in neurosciences is to elucidate the formation and retrieval of brain's associative memory traces in real-time. Here, we describe real-time neural ensemble transient dynamics in the mouse hippocampal CA1 region and demonstrate their relationships with behavioral performances during both learning and recall. We employed the classic trace fear conditioning paradigm involving a neutral tone followed by a mild foot-shock 20 seconds later. Our large-scale recording and decoding methods revealed that conditioned tone responses and tone-shock association patterns were not present in CA1 during the first pairing, but emerged quickly after multiple pairings. These encoding patterns showed increased immediate-replay, correlating tightly with increased immediate-freezing during learning. Moreover, during contextual recall, these patterns reappeared in tandem six-to-fourteen times per minute, again correlating tightly with behavioral recall. Upon traced tone recall, while various fear memories were retrieved, the shock traces exhibited a unique recall-peak around the 20-second trace interval, further signifying the memory of time for the expected shock. Therefore, our study has revealed various real-time associative memory traces during learning and recall in CA1, and demonstrates that real-time memory traces can be decoded on a moment-to-moment basis over any single trial.

Random ray-tracing and graphic analysing of charged particle trajectories

International Nuclear Information System (INIS)

Lin Xiaomei; Mao Naifeng; Chen Jingxian

1990-01-01

In order to describe the optical properties of a charged particle beam realistically, the random sampling of initial conditions of particles in ray-tracing is discussed. The emission surface of particles may be a plane, a cylindrical surface or a spherical surface. The distribution functions may be expressed analytically or numerically. In order to analyse the properties of the charged particle beam systematically by use of the results from ray-tracing efficiently, the graphic processing and analysing of particle trajectories are also discussed, including the spline function fitting of trajectories, the graphic drafting of trajectories and beam envelopes, the determining of image dimensions and the correspinding positions, and also the graphic drafting of particle distributions on arbitrary cross sections

Technical Efficiency and Organ Transplant Performance: A Mixed-Method Approach

Science.gov (United States)

de-Pablos-Heredero, Carmen; Fernández-Renedo, Carlos; Medina-Merodio, Jose-Amelio

2015-01-01

Mixed methods research is interesting to understand complex processes. Organ transplants are complex processes in need of improved final performance in times of budgetary restrictions. As the main objective a mixed method approach is used in this article to quantify the technical efficiency and the excellence achieved in organ transplant systems and to prove the influence of organizational structures and internal processes in the observed technical efficiency. The results show that it is possible to implement mechanisms for the measurement of the different components by making use of quantitative and qualitative methodologies. The analysis show a positive relationship between the levels related to the Baldrige indicators and the observed technical efficiency in the donation and transplant units of the 11 analyzed hospitals. Therefore it is possible to conclude that high levels in the Baldrige indexes are a necessary condition to reach an increased level of the service offered. PMID:25950653

An Efficient Approach for Solving Mesh Optimization Problems Using Newton’s Method

Directory of Open Access Journals (Sweden)

Jibum Kim

2014-01-01

Full Text Available We present an efficient approach for solving various mesh optimization problems. Our approach is based on Newton’s method, which uses both first-order (gradient and second-order (Hessian derivatives of the nonlinear objective function. The volume and surface mesh optimization algorithms are developed such that mesh validity and surface constraints are satisfied. We also propose several Hessian modification methods when the Hessian matrix is not positive definite. We demonstrate our approach by comparing our method with nonlinear conjugate gradient and steepest descent methods in terms of both efficiency and mesh quality.

Speciation of protein-bound trace elements by gel electrophoresis and atomic spectrometry.

Science.gov (United States)

Ma, Renli; McLeod, Cameron W; Tomlinson, Kerry; Poole, Robert K

2004-08-01

The metabolism of trace elements, in particular their binding to proteins in biological systems is of great importance in biochemical, toxicological, and pharmacological studies. As a result there has been a sustained interest over the last two decades in the speciation of protein-bound metals. Various analytical approaches have been employed, combining efficient separation of metalloproteins by liquid chromatography or electrophoresis with high-sensitivity elemental detection. Slab-gel electrophoresis (GE) is a key platform for high-resolution protein separation, and has been combined with autoradiography and various atomic spectrometric techniques for in-gel determination of protein-bound metals. Recently, the combination of GE with state-of-the-art inductively coupled plasma-mass spectrometry (ICP-MS), particularly when linked to laser ablation (LA) for direct gel interrogation, has opened up new opportunities for rapid characterization of metalloproteins. The use of GE and atomic spectrometry for the speciation of protein-bound trace elements is reviewed in this paper. Technical requirements for gel electrophoresis/atomic spectrometric measurement are considered in terms of method compatibilities, detection capability and potential usefulness. The literature is also surveyed to illustrate current status and future trends. Copyright 2004 Wiley-VCH Verlag GmbH and Co.

Behaviour study of trace radioelements in the cycles of uranium conversion

International Nuclear Information System (INIS)

Bertaux, M.

1998-01-01

The aim of this work was to study the presence of ultra-trace radioelements in the cycles of uranium conversion. Radiochemical methods for determining ultra-trace amounts of various elements in uranium have been perfected. These methods are based on the chromatographic separation of anionic complexes and on the measurement of various activities by alpha spectrometry. Thus, the source of these traces has been determined and a work of tracing has been carried out in the Malvesi site (uranium purification unit). This work has revealed an accumulation of these traces in the uranium purification column, consequently to their extraction by the TBP. A decontamination process of weakly contaminated uranium batches has been proposed using the Parex computer model and tested at the industrial scale. This process is based on the U(VI) extraction by the TBP/ISOPAR mixture and on the use of oxalic acid as the complexing agent of the tetravalent actinides in aqueous phase. It has been tested with success during a purification study of a batch of about 4 tons of uranium contaminated by traces of various radioelements. The preliminary study had taken into account the influence of metallic impurities (iron, nickel, copper) on the radioelements complexation by the oxalate ions. (O.M.)

Improving Light Outcoupling Efficiency for OLEDs with Microlens Array Fabricated on Transparent Substrate

Directory of Open Access Journals (Sweden)

Jun Wang

2014-01-01

Full Text Available Low light outcoupling efficiency restricts the wide application of organic light-emitting diodes in solid state light market although the internal quantum efficiency of the device could reach near to 100%. In order to improve the output efficiency, different kinds of microlens array on the substrate emission surface were designed and simulated using light tracing method. Simulation results indicate that the microlens array on the substrate could efficiently improve the light output efficiency and an enhancement of 1.8 could be obtained with optimized microlens structure design. The microlens array with semicircle shape using polymer material was fabricated on glass substrate by a facile approach. Finally, the organic device with microlens array substrate was manufactured and the light output of the device with surface microlens structure could increase to 1.64 times comparing with the device without microlens.

A Method for Determining Optimal Residential Energy Efficiency Packages

Energy Technology Data Exchange (ETDEWEB)

Polly, B. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Gestwick, M. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Bianchi, M. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Anderson, R. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Horowitz, S. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Christensen, C. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Judkoff, R. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2011-04-01

This report describes an analysis method for determining optimal residential energy efficiency retrofit packages and, as an illustrative example, applies the analysis method to a 1960s-era home in eight U.S. cities covering a range of International Energy Conservation Code (IECC) climate regions. The method uses an optimization scheme that considers average energy use (determined from building energy simulations) and equivalent annual cost to recommend optimal retrofit packages specific to the building, occupants, and location.

An efficient method for DNA extraction from Cladosporioid fungi.

Science.gov (United States)

Moslem, M A; Bahkali, A H; Abd-Elsalam, K A; Wit, P J G M

2010-11-23

We developed an efficient method for DNA extraction from Cladosporioid fungi, which are important fungal plant pathogens. The cell wall of Cladosporioid fungi is often melanized, which makes it difficult to extract DNA from their cells. In order to overcome this we grew these fungi for three days on agar plates and extracted DNA from mycelium mats after manual or electric homogenization. High-quality DNA was isolated, with an A(260)/A(280) ratio ranging between 1.6 and 2.0. Isolated genomic DNA was efficiently digested with restriction enzymes and produced distinct banding patterns on agarose gels for the different Cladosporium species. Clear DNA fragments from the isolated DNA were amplified by PCR using small and large subunit rDNA primers, demonstrating that this method provides DNA of sufficiently high quality for molecular analyses.

Determination of ultra-trace aluminum in human albumin by cloud point extraction and graphite furnace atomic absorption spectrometry.

Science.gov (United States)

Sun, Mei; Wu, Qianghua

2010-04-15

A cloud point extraction (CPE) method for the preconcentration of ultra-trace aluminum in human albumin prior to its determination by graphite furnace atomic absorption spectrometry (GFAAS) had been developed in this paper. The CPE method was based on the complex of Al(III) with 1-(2-pyridylazo)-2-naphthol (PAN) and Triton X-114 was used as non-ionic surfactant. The main factors affecting cloud point extraction efficiency, such as pH of solution, concentration and kind of complexing agent, concentration of non-ionic surfactant, equilibration temperature and time, were investigated in detail. An enrichment factor of 34.8 was obtained for the preconcentration of Al(III) with 10 mL solution. Under the optimal conditions, the detection limit of Al(III) was 0.06 ng mL(-1). The relative standard deviation (n=7) of sample was 3.6%, values of recovery of aluminum were changed from 92.3% to 94.7% for three samples. This method is simple, accurate, sensitive and can be applied to the determination of ultra-trace aluminum in human albumin. 2009 Elsevier B.V. All rights reserved.

A novel MPPT method for enhancing energy conversion efficiency taking power smoothing into account

International Nuclear Information System (INIS)

Liu, Jizhen; Meng, Hongmin; Hu, Yang; Lin, Zhongwei; Wang, Wei

2015-01-01

Highlights: • We discuss the disadvantages of conventional OTC MPPT method. • We study the relationship between enhancing efficiency and power smoothing. • The conversion efficiency is enhanced and the volatility of power is suppressed. • Small signal analysis is used to verify the effectiveness of proposed method. - Abstract: With the increasing capacity of wind energy conversion system (WECS), the rotational inertia of wind turbine is becoming larger. And the efficiency of energy conversion is significantly reduced by the large inertia. This paper proposes a novel maximum power point tracking (MPPT) method to enhance the efficiency of energy conversion for large-scale wind turbine. Since improving the efficiency may increase the fluctuations of output power, power smoothing is considered as the second control objective. A T-S fuzzy inference system (FIS) is adapted to reduce the fluctuations according to the volatility of wind speed and accelerated rotor speed by regulating the compensation gain. To verify the effectiveness, stability and good dynamic performance of the new method, mechanism analyses, small signal analyses, and simulation studies are carried out based on doubly-fed induction generator (DFIG) wind turbine, respectively. Study results show that both the response speed and the efficiency of proposed method are increased. In addition, the extra fluctuations of output power caused by the high efficiency are reduced effectively by the proposed method with FIS

TraceContract: A Scala DSL for Trace Analysis

Science.gov (United States)

Barringer, Howard; Havelund, Klaus

2011-01-01

In this paper we describe TRACECONTRACT, an API for trace analysis, implemented in the SCALA programming language. We argue that for certain forms of trace analysis the best weapon is a high level programming language augmented with constructs for temporal reasoning. A trace is a sequence of events, which may for example be generated by a running program, instrumented appropriately to generate events. The API supports writing properties in a notation that combines an advanced form of data parameterized state machines with temporal logic. The implementation utilizes SCALA's support for defining internal Domain Specific Languages (DSLs). Furthermore SCALA's combination of object oriented and functional programming features, including partial functions and pattern matching, makes it an ideal host language for such an API.

Development of an in situ solvent formation microextraction and preconcentration method based on ionic liquids for the determination of trace cobalt (II in water samples by flame atomic absorption spectrometry

Directory of Open Access Journals (Sweden)

Mohammad Reza Jamali

2017-02-01

Full Text Available A simple in situ solvent formation microextraction (ISFME methodology based on the application of ionic liquid (IL as an extractant solvent and sodium hexafluorophosphate (NaPF6 as an ion-pairing agent was proposed for the preconcentration of the trace levels of cobalt ions. In this method cobalt was complexed with 2-(5-bromo-2-pyridylazo-5-diethylaminophenol (5-Br-PADAP and extracted into an ionic liquid phase. After phase separation, the enriched analyte in the final solution is determined by flame atomic absorption spectrometry (FAAS. Some effective factors that influence the microextraction efficiency were investigated and optimized. Under the optimum experimental conditions, the limit of detection and the enrichment factor were 0.97 μg L−1 and 50, respectively. The relative standard deviation (R.S.D. was obtained as 2.4%. The proposed method was assessed through the analysis of certified reference water and recovery experiments.

Technical Efficiency Among Cassava Farmers im Ikenne Local ...

African Journals Online (AJOL)

Cassava has played and continues to play a remarkable role on the agricultural stage of Nigeria. The inability of the country meeting existing demand has been traced to resource use efficiency of the farmers. The study evaluates the technical efficiency among cassava farmers in Ikenne Local Government Area of Ogun ...

High precision ray tracing in cylindrically symmetric electrostatics

Energy Technology Data Exchange (ETDEWEB)

Edwards Jr, David, E-mail: dej122842@gmail.com

2015-11-15

Highlights: • High precision ray tracing is formulated using power series techniques. • Ray tracing is possible for fields generated by solution to laplace's equation. • Spatial and temporal orders of 4–10 are included. • Precisions in test geometries of hemispherical deflector analyzer of ∼10{sup −20} have been obtained. • This solution offers a considerable extension to the ray tracing accuracy over the current state of art. - Abstract: With the recent availability of a high order FDM solution to the curved boundary value problem, it is now possible to determine potentials in such geometries with considerably greater accuracy than had been available with the FDM method. In order for the algorithms used in the accurate potential calculations to be useful in ray tracing, an integration of those algorithms needs to be placed into the ray trace process itself. The object of this paper is to incorporate these algorithms into a solution of the equations of motion of the ray and, having done this, to demonstrate its efficacy. The algorithm incorporation has been accomplished by using power series techniques and the solution constructed has been tested by tracing the medial ray through concentric sphere geometries. The testing has indicated that precisions of ray calculations of 10{sup −20} are now possible. This solution offers a considerable extension to the ray tracing accuracy over the current state of art.

Management Methods of Energy Efficiency and reduction of Greenhouse Gas Emissions

International Nuclear Information System (INIS)

Actina, G.; Grackova, L.; Zebergs, V.; Zeltins, N.

2007-01-01

The management methods of energy efficiency and reduction of GHG emissions and their introduction depend on the financing possibilities and the management structures. Analysis is made of the following methods for the management of the process of raising energy efficiency: an energy audit and certification; the third-party financing; networks for energy efficiency and services of raising energy efficiency. In Latvia more than a half of all the energy resources are consumed for heating and the supply of hot water. The thermal parameters of buildings are poor therefore wide introduction of buildings certification, based on energy audit is of particular importance. The third-party financing would allow resolving the justified problems of audit and certification in order to hasten the heating process of buildings, particularly, owing to the appearance of respective foreign third-party financing companies, although the privatisation of dwelling houses and reorganisation of their management is not yet completed. The networks for energy efficiency have not found supporters in Latvia, however, great importance is attached to the thermal parameters of industrial premises, which are as poor as in the other buildings of the country, and here is a considerable potential of energy economy. Concerning the services of raising energy efficiency, the management method of this process is supposed to reach maximum energy economy after thermo and technical renovation of buildings at their various stages. It is connected with general organisational and financial adjustment of the management of buildings, as well as with the development of the energy service company.(author)

Validation of the intrinsic spatial efficiency method for non cylindrical homogeneous sources using MC simulation

Energy Technology Data Exchange (ETDEWEB)

Ortiz-Ramírez, Pablo, E-mail: rapeitor@ug.uchile.cl; Ruiz, Andrés [Departamento de Física, Facultad de Ciencias, Universidad de Chile (Chile)

2016-07-07

The Monte Carlo simulation of the gamma spectroscopy systems is a common practice in these days. The most popular softwares to do this are MCNP and Geant4 codes. The intrinsic spatial efficiency method is a general and absolute method to determine the absolute efficiency of a spectroscopy system for any extended sources, but this was only demonstrated experimentally for cylindrical sources. Due to the difficulty that the preparation of sources with any shape represents, the simplest way to do this is by the simulation of the spectroscopy system and the source. In this work we present the validation of the intrinsic spatial efficiency method for sources with different geometries and for photons with an energy of 661.65 keV. In the simulation the matrix effects (the auto-attenuation effect) are not considered, therefore these results are only preliminaries. The MC simulation is carried out using the FLUKA code and the absolute efficiency of the detector is determined using two methods: the statistical count of Full Energy Peak (FEP) area (traditional method) and the intrinsic spatial efficiency method. The obtained results show total agreement between the absolute efficiencies determined by the traditional method and the intrinsic spatial efficiency method. The relative bias is lesser than 1% in all cases.

Applications of stable isotope analysis to atmospheric trace gas budgets

Directory of Open Access Journals (Sweden)

Brenninkmeijer C. A.M.

2009-02-01

Full Text Available Stable isotope analysis has become established as a useful method for tracing the budgets of atmospheric trace gases and even atmospheric oxygen. Several new developments are briefly discussed in a systematic way to give a practical guide to the scope of recent work. Emphasis is on applications and not on instrumental developments. Processes and reactions are less considered than applications to resolve trace gas budgets. Several new developments are promising and applications hitherto not considered to be possible may allow new uses.

The Determination of Uranium and Trace Metal Impurities in Yellow Cake Sample by Chemical Method

International Nuclear Information System (INIS)

Busamongkol, Arporn; Rodthongkom, Chouvana

1999-01-01

The purity of uranium cake is very critical in nuclear-grade uranium (UO 2 ) and uranium hexafluoride (UF 6 ) production. The major element in yellow cake is uranium and trace metal impurities. The objective of this study is to determine uranium and 25 trace metal impurities; Aluminum, Barium, Bismuth, Calcium, Cadmium, Cobalt, Chromium, Copper, Iron, Potassium, Iithium, Magnesium, Manganese, Molybdenum, Sodium, Niobium, Nickel, Lead, Antimony, Tin, Strontium, Titanium, Vanadium, Zinc and Zirconium, Uranium is determined by Potassium dichromate titration, after solvent extraction with Cupferon in Chloroform, Trace metal impurities are determined by solvent extraction with Tributyl Phosphate in Carbon-tetrachloride ( for first 23 elements) and N-Benzoyl-N-Phenylhydroxylamine in Chloroform ( for last 2 elements), then analyzed by Atomic Absorption Spectrophotometer (AAS) compared with Inductively Couple Plasma Spectrophotometers (ICP). The accuracy and precision are studied with standard uranium octaoxide

An efficient method for sampling the essential subspace of proteins

NARCIS (Netherlands)

Amadei, A; Linssen, A.B M; de Groot, B.L.; van Aalten, D.M.F.; Berendsen, H.J.C.

A method is presented for a more efficient sampling of the configurational space of proteins as compared to conventional sampling techniques such as molecular dynamics. The method is based on the large conformational changes in proteins revealed by the ''essential dynamics'' analysis. A form of

The method of modular characteristic direction probabilities in MPACT

Energy Technology Data Exchange (ETDEWEB)

Liu, Z. [School of Nuclear Science and Technology, Xi' an Jiaotong University, No. 28 Xianning west road, Xi' an, Shaanxi 710049 (China); Kochunas, B.; Collins, B.; Downar, T. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, 2200 Bonisteel, Ann Arbor, MI 48109 (United States); Wu, H. [School of Nuclear Science and Technology, Xi' an Jiaotong University, No. 28 Xianning west road, Xi' an, Shaanxi 710049 (China)

2013-07-01

The method of characteristic direction probabilities (CDP) is based on a modular ray tracing technique which combines the benefits of the collision probability method (CPM) and the method of characteristics (MOC). This past year CDP was implemented in the transport code MPACT for 2-D and 3-D transport calculations. By only coupling the fine mesh regions passed by the characteristic rays in the particular direction, the scale of the probabilities matrix is much smaller compared to the CPM. At the same time, the CDP has the same capacity of dealing with the complicated geometries with the MOC, because the same modular ray tracing techniques are used. Results from the C5G7 benchmark problems are given for different cases to show the accuracy and efficiency of the CDP compared to MOC. For the cases examined, the CDP and MOC methods were seen to differ in k{sub eff} by about 1-20 pcm, and the computational efficiency of the CDP appears to be better than the MOC for some problems. However, in other problems, particularly when the CDP matrices have to be recomputed from changing cross sections, the CDP does not perform as well. This indicates an area of future work. (authors)

Evaluation of a new electronic preoperative reference marker for toric intraocular lens implantation by two different methods of analysis: Adobe Photoshop versus iTrace.

Science.gov (United States)

Farooqui, Javed Hussain; Sharma, Mansi; Koul, Archana; Dutta, Ranjan; Shroff, Noshir Minoo

2017-01-01

The aim of this study is to compare two different methods of analysis of preoperative reference marking for toric intraocular lens (IOL) after marking with an electronic marker. Cataract and IOL Implantation Service, Shroff Eye Centre, New Delhi, India. Fifty-two eyes of thirty patients planned for toric IOL implantation were included in the study. All patients had preoperative marking performed with an electronic preoperative two-step toric IOL reference marker (ASICO AE-2929). Reference marks were placed at 3-and 9-o'clock positions. Marks were analyzed with two systems. First, slit-lamp photographs taken and analyzed using Adobe Photoshop (version 7.0). Second, Tracey iTrace Visual Function Analyzer (version 5.1.1) was used for capturing corneal topograph examination and position of marks noted. Amount of alignment error was calculated. Mean absolute rotation error was 2.38 ± 1.78° by Photoshop and 2.87 ± 2.03° by iTrace which was not statistically significant ( P = 0.215). Nearly 72.7% of eyes by Photoshop and 61.4% by iTrace had rotation error ≤3° ( P = 0.359); and 90.9% of eyes by Photoshop and 81.8% by iTrace had rotation error ≤5° ( P = 0.344). No significant difference in absolute amount of rotation between eyes when analyzed by either method. Difference in reference mark positions when analyzed by two systems suggests the presence of varying cyclotorsion at different points of time. Both analysis methods showed an approximately 3° of alignment error, which could contribute to 10% loss of astigmatic correction of toric IOL. This can be further compounded by intra-operative marking errors and final placement of IOL in the bag.

Efficient methods for time-absorption (α) eigenvalue calculations

International Nuclear Information System (INIS)

Hill, T.R.

1983-01-01

The time-absorption eigenvalue (α) calculation is one of the options found in most discrete-ordinates transport codes. Several methods have been developed at Los Alamos to improve the efficiency of this calculation. Two procedures, based on coarse-mesh rebalance, to accelerate the α eigenvalue search are derived. A hybrid scheme to automatically choose the more-effective rebalance method is described. The α rebalance scheme permits some simple modifications to the iteration strategy that eliminates many unnecessary calculations required in the standard search procedure. For several fast supercritical test problems, these methods resulted in convergence with one-fifth the number of iterations required for the conventional eigenvalue search procedure

Tracing pathogens in the food chain

NARCIS (Netherlands)

Brul, S.; Fratamico, P.M.; McMeekin, T.A.

2010-01-01

Successful methods for the detection and investigation of outbreaks of foodborne disease are essential for ensuring consumer safety. Increased understanding of the transmission of pathogens in food chains will also assist efforts to safeguard public health. Tracing pathogens in the food chain

Sparse RNA folding revisited: space-efficient minimum free energy structure prediction.

Science.gov (United States)

Will, Sebastian; Jabbari, Hosna

2016-01-01

RNA secondary structure prediction by energy minimization is the central computational tool for the analysis of structural non-coding RNAs and their interactions. Sparsification has been successfully applied to improve the time efficiency of various structure prediction algorithms while guaranteeing the same result; however, for many such folding problems, space efficiency is of even greater concern, particularly for long RNA sequences. So far, space-efficient sparsified RNA folding with fold reconstruction was solved only for simple base-pair-based pseudo-energy models. Here, we revisit the problem of space-efficient free energy minimization. Whereas the space-efficient minimization of the free energy has been sketched before, the reconstruction of the optimum structure has not even been discussed. We show that this reconstruction is not possible in trivial extension of the method for simple energy models. Then, we present the time- and space-efficient sparsified free energy minimization algorithm SparseMFEFold that guarantees MFE structure prediction. In particular, this novel algorithm provides efficient fold reconstruction based on dynamically garbage-collected trace arrows. The complexity of our algorithm depends on two parameters, the number of candidates Z and the number of trace arrows T; both are bounded by [Formula: see text], but are typically much smaller. The time complexity of RNA folding is reduced from [Formula: see text] to [Formula: see text]; the space complexity, from [Formula: see text] to [Formula: see text]. Our empirical results show more than 80 % space savings over RNAfold [Vienna RNA package] on the long RNAs from the RNA STRAND database (≥2500 bases). The presented technique is intentionally generalizable to complex prediction algorithms; due to their high space demands, algorithms like pseudoknot prediction and RNA-RNA-interaction prediction are expected to profit even stronger than "standard" MFE folding. SparseMFEFold is free

Separation, preconcentration and estimation of rare earth and trace elements by inductively coupled plasma-atomic emission spectrometry (ICP-AES) in thorium matrices

International Nuclear Information System (INIS)

Chakraborty, Prithwish; Kumar Vijay; Durani, Smeer; Satyanarayana, K.

2007-01-01

A simple, sensitive and efficient method is developed for the separation of Rare earth elements (REEs) La-Lu, and Y and some trace elements Cd, Co, Cr, Cu, Ni,V, Zn from thorium matrix and their subsequent estimations by ICP-AES. In thorium-rich geological samples, the estimation of REE's by ICP-AES suffers from the spectral interferences due to the presence of excess of Th. In the proposed method, thorium is separated from the matrix by the solvent extraction. To optimize the separation, of REEs and trace elements from Th matrix, synthetic mixture solutions was prepared containing Th, REEs and trace elements maintaining different acidic conditions (1M, 2M, 4M, 6M, 8M and 10M HNO 3 and 2M, 4M, 6M and 8M HCl) and each solution was subjected to solvent extraction. The solvent extraction was carried out using a mixture of di-2-ethylhexyl phosphoric acid (in 30 % Toluene) and 1- pentanol in the ratio of 5:1. The aqueous phase containing the required elements was evaporated to dryness and an acidity of 5% HCl is maintained in final volume. Solutions were analysed by ICP-AES and the quantitative recovery of REEs and trace elements were obtained at 6M HNO 3 acidity. The developed method was applied to the certified standard reference material: IGS-36 and the values obtained were comparable with the certified values. The method was also applied to the real time monazite sample and the recovery was quantitative. Corrections have been applied for the REEs inter-elemental interferences in ICP-AES. (author)

Trace elements in nail polish as a source of contamination of nail clippings when used in epidemiological studies

International Nuclear Information System (INIS)

Favaro, P.C.; Bode, P.; De Nadai Fernandes, E.A.

2005-01-01

Trace elements were determined in 27 brands of nail polish using INAA so as to estimate the impact of nail polish remainders when using (finger, toe) nail clippings as a bioindicator for epidemiological studies. Fe was found to be present up to almost 1.7% in one brand. No unambiguous correlation between trace elements and color was established, though transparent polish has the lowest trace element concentrations. An estimate of the maximum effect (no removal of the paint) indicates that over-estimates of some trace element levels in nail with more than 200.000% may occur. If nail clippings will be used to study trace elements, very high demands have to be set to the efficiency and selectivity of the cleaning procedure. (author)

Concentration of trace elements on branded cigarette in Malaysia

International Nuclear Information System (INIS)

Azman, Muhammad Azfar; Hamzah, Suhaimi; Rahman, Shamsiah Abdul; Elias, Md Suhaimi; Abdullah, Nazaratul Ashifa; Hashim, Azian; Shukor, Shakirah Abd; Yasir, Muhamad Samudi; Rahman, Irman Abdul

2016-01-01

Tobacco is a plant that is used as a recreational drug since the beginning of its use by the Native Americans. Now with the development of the tobacco industry, smoking has become a norm for the public in Malaysia. Trace elements in plants are mostly due to the uptake processes from the soils into the roots of the plants. The concentration of the elements may also be influenced by the elements contained in the water and also fertilizers. This paper aim to analyze the concentration of the trace elements contained in the branded cigarettes sold in Malaysia by utilizing the neutron activation analysis. The tobaccos were taken out from the cigarettes. The collected samples were air dried and passed through 2 mm sieve. Instrumental Neutron Activation Analysis (NAA) has been used for the determination of trace elements. Samples were activated in the Nuclear Malaysia Triga Mark II reactor with a neutron flux of 2.0 x 10 12 n cm -2 s -1 . The samples then were analyzed using ORTEC Gamma Spectrometer a co-axial n-type HPGe detector with resolution of 2.0 keV at 1332 keV and relative efficiency of 20%. The data obtained could help in assessing the concentration of the trace elements that complying with the standard limitation dose proposed by World Health Organization (WHO)

Concentration of trace elements on branded cigarette in Malaysia