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Sample records for dilution method preparacion

  1. Preparation of standard mixtures of gas hydrocarbons in air by the diffusion dilution method; Preparacion de mezclas patrones de hidrocarburos gaseosos en aire por el metodo de dilucion por difusion

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, M R; Perez, M M

    1979-07-01

    An original diffusion system able to produce continuously gaseous samples is described. This system can generate samples with concentrations of benzene in air from 0.1 to 1 ppm a reproducible way. The diffusion dilution method used Is also studied. The use of this diffusion system has been extended to the preparation of binary mixtures (benzene-toluene). Whit a secondary dilution device is possible preparing these mixtures over a wide range of concentrations (0.11 to 0.04 ppm for benzene and 0.06 to 0.02 for toluene). (Author) 7 refs.

  2. Dilute Surfactant Methods for Carbonate Formations

    Energy Technology Data Exchange (ETDEWEB)

    Kishore K. Mohanty

    2006-02-01

    There are many fractured carbonate reservoirs in US (and the world) with light oil. Waterflooding is effective in fractured reservoirs, if the formation is water-wet. Many fractured carbonate reservoirs, however, are mixed-wet and recoveries with conventional methods are low (less than 10%). The process of using dilute anionic surfactants in alkaline solutions has been investigated in this work for oil recovery from fractured oil-wet carbonate reservoirs both experimentally and numerically. This process is a surfactant-aided gravity drainage where surfactant diffuses into the matrix, lowers IFT and contact angle, which decrease capillary pressure and increase oil relative permeability enabling gravity to drain the oil up. Anionic surfactants have been identified which at dilute concentration of 0.05 wt% and optimal salinity can lower the interfacial tension and change the wettability of the calcite surface to intermediate/water-wet condition as well or better than the cationic surfactant DTAB with a West Texas crude oil. The force of adhesion in AFM of oil-wet regions changes after anionic surfactant treatment to values similar to those of water-wet regions. The AFM topography images showed that the oil-wetting material was removed from the surface by the anionic surfactant treatment. Adsorption studies indicate that the extent of adsorption for anionic surfactants on calcite minerals decreases with increase in pH and with decrease in salinity. Surfactant adsorption can be minimized in the presence of Na{sub 2}CO{sub 3}. Laboratory-scale surfactant brine imbibition experiments give high oil recovery (20-42% OOIP in 50 days; up to 60% in 200 days) for initially oil-wet cores through wettability alteration and IFT reduction. Small (<10%) initial gas saturation does not affect significantly the rate of oil recovery in the imbibition process, but larger gas saturation decreases the oil recovery rate. As the core permeability decreases, the rate of oil recovery reduces

  3. A simple approximation method for dilute Ising systems

    International Nuclear Information System (INIS)

    Saber, M.

    1996-10-01

    We describe a simple approximate method to analyze dilute Ising systems. The method takes into consideration the fluctuations of the effective field, and is based on a probability distribution of random variables which correctly accounts for all the single site kinematic relations. It is shown that the simplest approximation gives satisfactory results when compared with other methods. (author). 12 refs, 2 tabs

  4. Simplified Method for Groundwater Treatment Using Dilution and Ceramic Filter

    Science.gov (United States)

    Musa, S.; Ariff, N. A.; Kadir, M. N. Abdul; Denan, F.

    2016-07-01

    Groundwater is one of the natural resources that is not susceptible to pollutants. However, increasing activities of municipal, industrial, agricultural or extreme land use activities have resulted in groundwater contamination as occured at the Research Centre for Soft Soil Malaysia (RECESS), Universiti Tun Hussein Onn Malaysia (UTHM). Thus, aims of this study is to treat groundwater by using rainwater and simple ceramic filter as a treatment agent. The treatment uses rain water dilution, ceramic filters and combined method of dilute and filtering as an alternate treatment which are simple and more practical compared to modern or chemical methods. The water went through dilution treatment processes able to get rid of 57% reduction compared to initial condition. Meanwhile, the water that passes through the filtering process successfully get rid of as much as 86% groundwater parameters where only chloride does not pass the standard. Favorable results for the combination methods of dilution and filtration methods that can succesfully eliminate 100% parameters that donot pass the standards of the Ministry of Health and the Interim National Drinking Water Quality Standard such as those found in groundwater in RECESS, UTHM especially sulfate and chloride. As a result, it allows the raw water that will use clean drinking water and safe. It also proves that the method used in this study is very effective in improving the quality of groundwater.

  5. Quality of potential harmonics expansion method for dilute Bose ...

    Indian Academy of Sciences (India)

    Abstract. We present and examine an approximate but ab initio many-body approach, viz., potential harmonics expansion method (PHEM), which includes two-body correla- tions for dilute Bose–Einstein condensates. Comparing the total ground state energy for three trapped interacting bosons calculated in PHEM with the ...

  6. Determination of photooxygenation products of rotenone with isotope dilution method

    International Nuclear Information System (INIS)

    Chubachi, Mitsuo; Hamada, Masayuki

    1975-01-01

    When rotenone dissolved in certain solvent was photochemically oxidized, rotenolones, dehydrorotenone and rotenonone were obtained as main products. In order to determine the quantitative yields of these compounds in photooxygenation products, four compounds mentioned above were labeled with carbon-14 and the isotope dilution method by these labeled compounds was applied to the product analysis. (auth.)

  7. Development of curcumin liposome formulations using polyol dilution method

    Directory of Open Access Journals (Sweden)

    Lalana Kongkaneramit

    2016-12-01

    Full Text Available This study was aimed to formulate curcumin liposomes (CLs by using polyol dilution method which is advantageous for no residue of organic solvent. CLs were the mixture of hydrogenated phosphatidylcholine (PC and cholesterol (CH at the molar ratio of 9:1. Propylene glycol (PG, glycerin, and polyethylene glycol 400 (PEG-400 were used as polyol solvent. Extrusion was applied after the suspension formed. The amount of polyol and curcumin and preparing temperature were investigated. The obtained suspensions were observed for appearance, size, size distribution, zeta potential, morphology, and percentage of entrapment. The results showed that type and amount of polyol had an impact on both liposomal size and the amount of entrapped curcumin, while preparing temperature was also an important factor. However, the solubility of lipids and drug in a given polyol should be considered because of loading efficiency in the formulation.

  8. Radiotracer Dilution Method for Mercury Inventory Study in Electrolytic Cells

    Science.gov (United States)

    Sugiharto, Su'ud, Zaki; Kurniadi, Rizal; Waris, Abdul; Santoso, Sigit Budi; Abidin, Zainal; Santoso, Gatot Budi

    2010-06-01

    Purpose of the experiment is to demonstrate feasibility the use of radiotracer to measure weight of mercury in electrolytic cells of soda industry. The weight of mercury in each cell of the plant is designed approximately 1700 kg. Radiotracer is prepared by mixing 203 Hg radioactive mercury with 2400 g of inactive mercury in a bath. The respective precisely weighted mercury aliquots to be injected into the cells are prepared by pouring approximately 130 g of radioactive mercury taken from the bath into 13 standard vials, in accordance with the number of the cells tested. Four standard references prepared by further dilution of ±2 g active mercury taken from the bath to obtain the dilution factors range of 12,000 to 20,000 from which the calibration graph is constructed. The injection process is conducting by pouring the radioactive mercury from aliquots into the flowing mercury at the inlet side of the cell and allows them to mix thoroughly. It is assumed that the mass of the radiotracer injected into a closed system remains constant, at least during the period of the test. From this experiment it was observed that the mixing time is two days after injection of radioactive mercury. The inactive mercury in each electrolytic cell calculated by the radiotracer method is of the range 1351.529 kg to 1966.354 kg with maximum error (95% confidence) is 1.52 %. The accuracy of measurement of the present method is better than gravimetric one which accounts 4 % of error on average.

  9. Radiotracer Dilution Method for Mercury Inventory Study in Electrolytic Cells

    International Nuclear Information System (INIS)

    Sugiharto; Su'ud, Zaki; Kurniadi, Rizal; Waris, Abdul; Santoso, Sigit Budi; Abidin, Zainal; Santoso, Gatot Budi

    2010-01-01

    Purpose of the experiment is to demonstrate feasibility the use of radiotracer to measure weight of mercury in electrolytic cells of soda industry. The weight of mercury in each cell of the plant is designed approximately 1700 kg. Radiotracer is prepared by mixing 203 Hg radioactive mercury with 2400 g of inactive mercury in a bath. The respective precisely weighted mercury aliquots to be injected into the cells are prepared by pouring approximately 130 g of radioactive mercury taken from the bath into 13 standard vials, in accordance with the number of the cells tested. Four standard references prepared by further dilution of ±2 g active mercury taken from the bath to obtain the dilution factors range of 12,000 to 20,000 from which the calibration graph is constructed. The injection process is conducting by pouring the radioactive mercury from aliquots into the flowing mercury at the inlet side of the cell and allows them to mix thoroughly. It is assumed that the mass of the radiotracer injected into a closed system remains constant, at least during the period of the test. From this experiment it was observed that the mixing time is two days after injection of radioactive mercury. The inactive mercury in each electrolytic cell calculated by the radiotracer method is of the range 1351.529 kg to 1966.354 kg with maximum error (95% confidence) is 1.52 %. The accuracy of measurement of the present method is better than gravimetric one which accounts 4 % of error on average.

  10. Agar dilution method for susceptibility testing of Neisseria gonorrhoeae

    Directory of Open Access Journals (Sweden)

    Marta C de Castillo

    1996-12-01

    Full Text Available The antibiotic susceptibilities of Neisseria gonorrhoeae isolates obtained from patients attending a clinic for sexually transmitted diseases in Tucumán, Argentina, were determined by the agar dilution method (MIC. 3.5% of the isolates produced ²-lactamase. A total of 96.5% of ²-lactamase negative isolates tested were susceptible to penicillin (MIC < 2 µgml-1; 14.03% of the tested isolates were resistant to tetracycline (MIC < 2 µgml-1, and 98% of the tested isolates were susceptible to spectinomycin (MIC < 64 µgml-1. The MICs for 95% of the isolates, tested for other drugs were: < 2 µgml-1 for cefoxitin, < 0.06 µgml-1 for cefotaxime, < 0.25 µgml-1 for norfloxacin, < 10 µgml-1 for cephaloridine, < 10 µgml-1 for cephalexin, and < 50 µgml-1 for kanamycin. Antibiotic resistance among N. gonorrhoeae isolates from Tucumán, Argentina, appeared to be primarily limited to penicillin and tetracycline, which has been a general use against gonorrhoeae in Tucumán since 1960. Periodic monitoring of the underlying susceptibility profiles of the N. gonorrhoeae strains prevalent in areas of frequent transmission may provide clues regarding treatment options and emerging of drug resistance.

  11. Method for the development of emergency response preparedness for nuclear or radiological accidents; Metodo para el desarrollo de la preparacion de la respuesta a emergencias nucleares o radiologicas

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    This report supplements IAEA emergency preparedness guidance published in the 1980s, and is consistent with the new international guidance. It provides practical advice for the development of an emergency response capability based on the potential nature and magnitude of the risk. In order to apply this method, emergency planners should have a good understanding of the basic radiological emergency response principles. Therefore, other applicable international guidance should be reviewed before using this report. This report provides a practical step-by-step method for developing integrated user, local and national emergency response capabilities. It can also be used as the basis for conducting an audit of an existing emergency response capability.

  12. Evaluation of isotopic dilution method for measuring N2 fixation in azolla: comparison with other methods

    International Nuclear Information System (INIS)

    Sah, R.N.; Goyal, S.S.; Rains, D.W.; Paige, D.F.

    1989-01-01

    An isotopic dilution method that overcomes the drawbacks of commonly used methods for measuring N 2 fixation by aquatic N‐fixers such as Azolla pinnata‐Anabaena azollae association (Azolla) is presented. The method was compared with 15 N2 gas (while maintaining CO 2 ) and the difference methods of measuring N 2 fixation. The isotopic dilution method was used for two conditions: a. For 15 N‐free growth medium, Azolla was pre‐enriched with 15 N, and N 2 fixation was determined by measuring the dilution of 15 N in the tissue. b. For the growth medium containing N, N2 fixation was determined by providing 15 N enriched ammonium sulfate in the growth medium and measuring 15 N to 14 N ratio in the tissue. An airtight chamber, necessary for 15 N 2 gas and acetylene reduction methods, was not representative of the growing environment of Azolla. Temperature in the airtight chamber was far from uniform and CO 2 was rapidly depleted. The isotopic dilution method is simpler, relatively inexpensive, subject to fewer errors and applicable to more diverse conditions, and yet was as accurate as 15 N2‐gas method. (author)

  13. Comparative determination of sucrose content in sugar beet by polarimetric and isotope dilution methods

    Energy Technology Data Exchange (ETDEWEB)

    Malec, K; Szuchnik, A [Institute of Nuclear Research, Warsaw (Poland); Rydel, S; Walerianaczyk, E [Instytut Przemyslu Cukrowniczego, Warsaw (Poland)

    1976-01-01

    The comparative determination of sucrose content in sugar beets has been investigated by following methods: polarimetric, direct isotope dilution and double carrier-isotope dilution analysis. Basing upon the obtained results it has been ascertained, that in the case of worse quality beets the polarimetric determinations differ greatly from isotopic data.

  14. Comparison of dye dilution method to radionuclide techniques for cardiac output determination in dogs

    International Nuclear Information System (INIS)

    Eng, S.S.; Robayo, J.R.; Porter, W.; Smith, R.E.

    1980-01-01

    A study was undertaken to identify the most accurate /sup 99m/Tc-labeled radiopharmaceutical and to determine the accuracy of a noninvasive radionuclide technique or cardiac output determinations. Phase I employed sodium pertechnetate, stannous pyrophosphate with sodium pertechnetate, /sup 99m/Tc red blood cells, and /sup 99m/Tc human serum albumin as radionuclide tracers. Cardiac output was determined by the dye dilution method and then by the invasive radionuclide technique. A pairied t test and regression analysis indicated that /sup 99m/Tc human serum albumin was the most accurate radiopharmaceutical for cardiac output determinations, and the results compared favorably to those obtained by the dye dilution method. In Phase II, /sup 99m/Tc human serum albumin was used as the radionuclide tracer for cardiac output determinations with the noninvasive technique. The results compared favorably to those obtained by the dye dilution method

  15. Preparation of standard mixtures of gas hydrocarbons in air by the diffusion dilution method

    International Nuclear Information System (INIS)

    Garcia, M. R.; Perez, M. M.

    1979-01-01

    An original diffusion system able to produce continuously gaseous samples is described. This system can generate samples with concentrations of benzene in air from 0.1 to 1 ppm a reproducible way. The diffusion dilution method used Is also studied. The use of this diffusion system has been extended to the preparation of binary mixtures (benzene-toluene). Whit a secondary dilution device is possible preparing these mixtures over a wide range of concentrations (0.11 to 0.04 ppm for benzene and 0.06 to 0.02 for toluene). (Author) 7 refs

  16. Deuterium dilution method for determining the Breast milk intake of babies

    International Nuclear Information System (INIS)

    Roohi, S.; Bilal, R.; Latif, Z.

    2000-11-01

    Various methods for measuring the milk intake of breast fed babies are available. Most methods are time consuming, cumbersome and inaccurate. The report describes various methods used for Breast Milk intake measurement with emphasis on the D/sub 2/O dilution method. The methodology of the D/sub 2/O dilution method is now streamlined in this Inst. for measuring the milk intake of babies. Advantages and disadvantages of all the methods used to determine the breast milk intake of the infants are also included in the present report. For the D/sub 2/O dilution method, and oral administration of small dose of deuterium oxide (sup 2/H/sup 2/O) is given to the mothers after collecting pre-dose samples. The post dose samples of urine from the baby and saliva from the mother are collected at 24 hours intervals over a 14 days period. These samples are analyzed on isotope ratio Mass spectrometer. The D/H values obtained over a 14 days period are then extrapolated to calculate the milk intake of babies using the Microsoft Excel Computer programme designed for this purpose. (author)

  17. Pleural liquid clearance rate measured in awake sheep by the volume of dilution method

    International Nuclear Information System (INIS)

    Broaddus, V.C.; Wiener-Kronish, J.P.; Berthiaume, Y.; Staub, N.C.

    1986-01-01

    The authors reported 24h clearance of mock pleural effusions measured terminally in sheep. To measure effusion volume at different times in the same sheep, they injected 111 In-transferrin and measured its dilution. In 5 sheep with effusions of known sizes, the method was accurate to +/-10%. In 5 awake sheep, the authors injected 10 ml/kg of a 1% protein solution via a non-penetrating rib capsule. At 6h, the authors measured the volume by the dilution method and at 24h by direct recovery. The clearance rate in each animal was constant at 2.9-6.0%/h (average 4.8 +/- 1.3%/h). This new method gives a reliable two point clearance rate and requires fewer animals

  18. Reverse isotope dilution method for determining benzene and metabolites in tissues

    International Nuclear Information System (INIS)

    Bechtold, W.E.; Sabourin, P.J.; Henderson, R.F.

    1988-01-01

    A method utilizing reverse isotope dilution for the analysis of benzene and its organic soluble metabolites in tissues of rats and mice is presented. Tissues from rats and mice that had been exposed to radiolabeled benzene were extracted with ethyl acetate containing known, excess quantities of unlabeled benzene and metabolites. Butylated hydroxytoluene was added as an antioxidant. The ethyl acetate extracts were analyzed with semipreparative reversed-phase HPLC. Isolated peaks were collected and analyzed for radioactivity (by liquid scintillation spectrometry) and for mass (by UV absorption). The total amount of each compound present was calculated from the mass dilution of the radiolabeled isotope. This method has the advantages of high sensitivity, because of the high specific activity of benzene, and relative stability of the analyses, because of the addition of large amounts of unlabeled carrier analogue

  19. Accuracy of the tritium water dilution method for determining water flux in reindeer (Rangifer tarandus)

    Energy Technology Data Exchange (ETDEWEB)

    Cameron, R D; White, R G; Luick, J R

    1976-06-01

    The accuracy of the tritium water dilution method in estimating water flux was evaluated in reindeer under various conditions of temperature and diet. Two non-pregnant female reindeer were restrained in metabolism stalls, within controlled-environment chambers, at temperatures of +10, -5, and -20/sup 0/C; varying amounts of a commercial pelleted ration (crude protein, 13 percent) or mixed lichens (crude protein, 3 percent) were offered, and water was provided ad libitum either as snow or in liquid form. Total body water volume and water turnover were estimated using tritiated water, and the daily outputs of feces and urine were measured for each of 12 different combinations of diet and temperature. Statistical analysis of the data showed that the tritium water dilution technique gives accurate determinations of total body water flux over a wide range of environmental and nutritional conditions.

  20. Estimation of nitrogen fixation in Saccharum spp. by 15N dilution method

    International Nuclear Information System (INIS)

    Singh, Mohan

    1994-01-01

    The amount of nitrogen fixed by bacteria associated with the roots of Saccharum spontaneum, S. sinense, and S. barberi has been estimated by 15 N-isotope dilution method using Sclerotachya fusca as a non-fixing control. S. spontaneum produced highest shoot dry weight among the species tested but maximum nitrogen was accumulated by S. barberi. Highest dilution in the 15 N-enrichment was observed in S. spontaneum followed by S. sinense and S. barberi in comparison to the control plant of Sclerotchya fusca. S. spontaneum derived 60 per cent followed by S. sinense 54 per cent and S. barberi 35 per cent of their total nitrogen requirement through fixation of nitrogen by diazotrophic bacteria associated with their roots. (author). 11 refs., 2 tabs

  1. Regression dilution bias: tools for correction methods and sample size calculation.

    Science.gov (United States)

    Berglund, Lars

    2012-08-01

    Random errors in measurement of a risk factor will introduce downward bias of an estimated association to a disease or a disease marker. This phenomenon is called regression dilution bias. A bias correction may be made with data from a validity study or a reliability study. In this article we give a non-technical description of designs of reliability studies with emphasis on selection of individuals for a repeated measurement, assumptions of measurement error models, and correction methods for the slope in a simple linear regression model where the dependent variable is a continuous variable. Also, we describe situations where correction for regression dilution bias is not appropriate. The methods are illustrated with the association between insulin sensitivity measured with the euglycaemic insulin clamp technique and fasting insulin, where measurement of the latter variable carries noticeable random error. We provide software tools for estimation of a corrected slope in a simple linear regression model assuming data for a continuous dependent variable and a continuous risk factor from a main study and an additional measurement of the risk factor in a reliability study. Also, we supply programs for estimation of the number of individuals needed in the reliability study and for choice of its design. Our conclusion is that correction for regression dilution bias is seldom applied in epidemiological studies. This may cause important effects of risk factors with large measurement errors to be neglected.

  2. Establishment and application of deuterium dilution method for measuring breastmilk intake of Pakistani infants

    International Nuclear Information System (INIS)

    Bilal, R.; Roohi, S.; Sajjad, M.I.; Abbas, K.A.; Latif, Z.

    2000-01-01

    We established the deuterium dilution method in our laboratory and have applied it in the field for quantification of milk intake of babies. A comparison of the test weighing (TW) data with the D 2 O data is also being made. The growth of children fed exclusively on breast milk is also being monitored. The method once established will be made available for various projects where correct estimation of milk intake/out put is desired. First year of the project was devoted to standardization of the D/H preparation from biological fluids using Zn shot method. During the report period, the D 2 O dilution methodology for measuring the breast milk intake of infants was streamlined. 21 infant-mother pairs have been recruited and data including deuterium dilution assay was collected at 4 weeks of age. Growth of the infants is being followed up-till six month. Analysis of 21 infant mothers data is presented. Samples of six infant mother pairs collected at 13. week of age are waiting to be analyzed. The mean breast milk intake of infants measured by deuterium dilution method is 801 ± 262 gm at first sampling at 31.15 ± 7.7 days of age (n=18). The milk intake determined by test weighing was significantly higher than estimated by D 2 O dilution. The values were 1169 ± 384 per day as compared to 705 ± 129 per day for TW and D 2 O method respectively (n=13). The growth data collected over six month period for 21 infants showed that they fall within 5 percentile of NCHS for weight. The height of boys is in 50 percentile whereas for girls it at 5 percentile. The data collected so far suggest that although majority of infants are exclusively breast fed and the intake values are normal yet their growth is far from optimum. This emphasizes the need to take up the studies involving quality of milk in relation to the nutritional status of the mothers. (author)

  3. A double isotope dilution method for assaying of polycyclic aromatic hydrocarbons in cigarette smoke condensate

    International Nuclear Information System (INIS)

    Bechtold, W.E.; Chen, B.T.

    1988-01-01

    This report describes a double isotope dilution method for analysis of the polycyclic aromatic hydrocarbons (PAH) phenanthrene, fluor-anthene, pyrene, and benzo[a]pyrene in cigarette smoke particulates. The first isotope dilution used deuterated analogues of the first three PAH as internal standards. The second isotope dilution, for benzo[a]pyrene, used the tritiated analogue as an internal standard. The PAH were isolated from extracts of cigarette smoke particulates using a two-step procedure based on selective extraction from aqueous dimethyl sulfoxide (DMSO) followed by chromatography on silica gel extraction columns. After isolation, aliquots of the samples were analyzed for phenanthrene, pyrene, and fluoranthene by gas chromatography with mass spectrometric detection (GC/MS). Separate aliquots of the samples were analyzed for benzo[a]pyrene by high pressure liquid chromatography with fluorescence detection followed by liquid scintillation spectrometry. PAH levels from cigarette smoke condensates collected from different exposure modes were compared; no exposure-related differences were found. (author)

  4. Synthesis of nano-sized amorphous boron powders through active dilution self-propagating high-temperature synthesis method

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jilin [The State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Gu, Yunle [School of Material Science and Engineering, Wuhan Institute of Technology, Wuhan 430073 (China); Li, Zili [The State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Wang, Weimin, E-mail: wangwm@hotmail.com [The State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Fu, Zhengyi [The State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China)

    2013-06-01

    Graphical abstract: Nano-sized amorphous boron powders were synthesized by active dilution self-propagating high-temperature synthesis (SHS) method. The effects of endothermic reaction rate, the possible chemical reaction mechanism and active dilution model for synthesis of the product were also discussed. Highlights: ► Nano-sized amorphous boron powders were synthesized by active dilution self-propagating high-temperature synthesis method. ► The morphology, particle size and purity of the samples could be effectively controlled via changing the endothermic rate. ► The diluter KBH{sub 4} played an important role in active dilution synthesis of amorphous nano-sized boron powders. ► The active dilution method could be further popularized and become a common approach to prepare various inorganic materials. - Abstract: Nano-sized amorphous boron powders were synthesized by active dilution self-propagating high-temperature synthesis (SHS) method at temperatures ranging from 700 °C to 850 °C in a SHS furnace using Mg, B{sub 2}O{sub 3} and KBH{sub 4} as raw materials. Samples were characterized by X-ray powder diffraction (XRD), Laser particle size analyzer, Fourier transform infrared spectra (FTIR), X-ray energy dispersive spectroscopy (EDX), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission TEM (HRTEM). The boron powders demonstrated an average particle size of 50 nm with a purity of 95.64 wt.%. The diluter KBH{sub 4} played an important role in the active dilution synthesis of amorphous nano-sized boron powders. The effects of endothermic reaction rate, the possible chemical reaction mechanism and active dilution model for synthesis of the product were also discussed.

  5. Synthesis of nano-sized amorphous boron powders through active dilution self-propagating high-temperature synthesis method

    International Nuclear Information System (INIS)

    Wang, Jilin; Gu, Yunle; Li, Zili; Wang, Weimin; Fu, Zhengyi

    2013-01-01

    Graphical abstract: Nano-sized amorphous boron powders were synthesized by active dilution self-propagating high-temperature synthesis (SHS) method. The effects of endothermic reaction rate, the possible chemical reaction mechanism and active dilution model for synthesis of the product were also discussed. Highlights: ► Nano-sized amorphous boron powders were synthesized by active dilution self-propagating high-temperature synthesis method. ► The morphology, particle size and purity of the samples could be effectively controlled via changing the endothermic rate. ► The diluter KBH 4 played an important role in active dilution synthesis of amorphous nano-sized boron powders. ► The active dilution method could be further popularized and become a common approach to prepare various inorganic materials. - Abstract: Nano-sized amorphous boron powders were synthesized by active dilution self-propagating high-temperature synthesis (SHS) method at temperatures ranging from 700 °C to 850 °C in a SHS furnace using Mg, B 2 O 3 and KBH 4 as raw materials. Samples were characterized by X-ray powder diffraction (XRD), Laser particle size analyzer, Fourier transform infrared spectra (FTIR), X-ray energy dispersive spectroscopy (EDX), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission TEM (HRTEM). The boron powders demonstrated an average particle size of 50 nm with a purity of 95.64 wt.%. The diluter KBH 4 played an important role in the active dilution synthesis of amorphous nano-sized boron powders. The effects of endothermic reaction rate, the possible chemical reaction mechanism and active dilution model for synthesis of the product were also discussed

  6. Evaluation for dinitrogen fixation of induced wheat nodules by 15N isotope dilution method

    International Nuclear Information System (INIS)

    Yao Yunyin; Zhen Ming; Chang Xizhong

    1993-11-01

    The results in pot experiments showed that the treating of 2,4-D and Azorhizobium caulinodans (2,4-D+A) could induce para-nodule formation on wheat roots. Plants treated grew normally. The plant height and dry weight are significantly higher than reference plants which are treated with 2,4-D+azorhizobium sterilized (2,4-D+AS). The nitrogenase activity is detected by ARA method. The N yield of most treated plants, especially in root systems, is higher than reference group that is measured by Kjeldahl method. The atom % 15 N excess in leaf and stem of treated plants measured by 15 N isotope dilution method is lower than that of reference group. Through four years experiments, it shows that para-nodules of wheat treated with 2,4-D+A could fix N 2 from air, but the ability of nitrogen fixation is lower and unstable. Although the nodulation efficiency could reach 100%, not each para-nodule induced can present activity of dinitrogen fixation. The amount of N fixed is 0.05∼18.1 mg/pot (0.01∼3.87 mg/plant). The net %Ndfa is 2.32%∼18.07%. The free-living N 2 fixing activity of azorhizobium is detected by 15 N isotope dilution method. The calculation of %Ndfa of nodulated wheat accurately is also discussed

  7. Pulsed Dilution Method for the Recovery of Aggregated Mouse TNF-α

    Directory of Open Access Journals (Sweden)

    Merat Mahmoodi

    2017-05-01

    Full Text Available Background: The expression of mouse tumor necrosis factor alpha (TNF-α in Escherichia coli is a favorable way to get high yield of protein; however, the formation of cytoplasmic inclusion bodies, which is the consequence of insoluble accumulated proteins, is a major obstacle in this system. To overcome this obstacle, we used a pulsed dilution method to convert the product to its native conformation. Methods: Reducing agent and guanidine hydrochloride were used to solubilize inclusion bodies formed after TNF-(α expression. Then, the refolding procedure was performed by pulsed dilution of the denatured protein into a refolding buffer. The properly-folded protein was purified by metal affinity chromatography. Results: SDS-PAGE showed a 19.9 kDa band related to the mature TNF-(α protein. The protein was recognized by anti-mouse TNF-(α on western blots. The final concentration of the purified recombinant TNF-(α was 62.5 μg/mL. Conclusions: Our study demonstrates the efficiency of this method to produce a high yield of folded mature TNF- (α.

  8. Effect of the method to prepare platinum-based nanoparticles versus electro-reduction of nitrates and proton adsorption; Efecto de la ruta de preparacion de nanoparticulas basadas en platino versus la electro-reduccion de nitratos y la adsorcion de protones

    Energy Technology Data Exchange (ETDEWEB)

    Estudillo-Wong, L.A.; Torres-Santillan, E.; Arce-Estrada, E.M.; J.R. Vargas-Garcia [Escuela Superior de Ingenieria Quimica e Industrias Extractivas (ESIQIE), IPN, Mexico D.F. (Mexico)]. E-mail: amanzor@ipn.mx; Alonso-Vante, N. [Universite de Poitiers, Poitiers (France); Manzo-Robledo, A. [Escuela Superior de Ingenieria Quimica e Industrias Extractivas (ESIQIE), IPN, Mexico D.F. (Mexico)

    2009-09-15

    The electro-reduction of nitrate ions (ERN) was carried out in an alkaline medium on platinum-tin nanoparticles, synthesized with metal organic chemical vapor deposition (MOCVD) and carbonyl complex route (CCR) and supported on carbon nanotubes (CNT) and Vulcan carbon. These catalysts were deposited on 4.0 mm diameter vitreous carbon. Cyclic voltametry was used to evaluate this reduction reaction. Different current magnitudes for hydrogen evolution reaction (HER) and ERN were found. Nevertheless, the proton and ion nitrate adsorption processes on the surface of the catalysts evaluated presented a potential range of -0.7 to -1.0V/SCE, indicating that the reaction mechanism is similar. Studies of nitrate concentrations indicate that the magnitude of the reduction current decreases and, in addition, different magnitudes are presented according to the catalyst/substrate used. These variations are explained by local disorder, due to the nature of the substrate, and the size of the nanoparticles resulting from the preparation method. Indirectly, the kinetic parameters calculated enable clarifying these suppositions. [Spanish] La electro-reduccion de iones nitrato (NER) sobre nano-particulas de platino-(estano) sintetizadas via MOCVD (metal organic chemical vapor deposition) y via carbonilo (carbonyl complex route, CCR) soportadas sobre nano-tubos de carbon (NTC) y carbon Vulcan (C), fue llevada a cabo en medio alcalino. Estos catalizadores fueron depositados sobre carbon vitreo de 4.0mm de diametro. La tecnica de voltametria ciclica fue utilizada para evaluar dicha reaccion de reduccion. Diferentes magnitudes de corriente versus la reaccion de evolucion de hidrogeno (HER) y la NER fueron encontradas. Sin embargo, los procesos de adsorcion de protones e iones nitrato en la superficie de los catalizadores evaluados se presentan en un intervalo de potencial de -0.7 a -1.0V/SCE, indicando que el mecanismo de reaccion es similar. Estudios en funcion de la concentracion de

  9. Evaluation of method for phthalate extraction from milk related to milk dilution ratio

    Directory of Open Access Journals (Sweden)

    Milojković Danica S.

    2015-01-01

    Full Text Available Liquid-liquid extraction techniques were compared coupled with gas chromatography-mass spectrometry (GC-MS, for the extraction and the determination of four phthalates: dimethyl phthalate (DMP, di-n-butyl phthalate (DBP, benzyl butyl phthalate (BBP and di-(2-ethylhexyl phthalate (DEHP in six different kinds of milk-based samples. Extraction factors: sample preparation, organic solvent type and volume, salt effect, agitation and the extraction time were optimized. The ion of base peaks (m/z 149 for DBP, BBP and DEHP and m/z 163 for DMP for investigated phthalates were selected for the screening studies. The acquisition was performed at the selected ion monitoring mode. The MSD response for GC-MS phthalate calibration standards was linear between 0.25 and 2.50 μg mL-1 with calculated LODs between 0.01 μg mL-1 to 0.04 μg mL-1 and LOQs of 0.05 μg mL-1 to 0.12 μg mL-1, while repeatability was between 1.7 % to 4.9 % RSD. The study demonstrated an increase of the recovery of less polar phthalates in matrix milk standards by matrix dilution. Recovery for hydrophilic phthalates, like DMP, was not changed by matrix dilution and it was continuously low for the investigated method. Two spiking levels were tested for influence of matrix dilution on phthalate recovery, showed the same trend. [Projekat Ministarstva nauke Republike Srbije, br. 31060

  10. Simpler and More Accurate: Weighing the Mercury in Electrolytic Cells by Radiotracer Dilution Method

    Directory of Open Access Journals (Sweden)

    Sugiharto

    2010-08-01

    Full Text Available Weight of mercury in electrolytic cell of soda industry is usually measured gravimetrically, which is typical labor work in character. Error sources of the gravimetric method might have come from the fact that some mercury’s are usually trapped in the cell due to complicated structure of electrolytic cell. This cause unknown errors. In addition, formation of amalgam at the cathode may cause a further uncertainty in the measurement. Total error from gravimetric method is 4% on average. Radiotracer dilution method provides advantages either for simplification of procedure and reduction of measurement error. In this experiment radioisotope mercury 203Hg, which was prepared in nuclear reactor was used to examine 13 of 14 electrolytic cells of soda plant. Each electrolytic cell was designed containing approximately 700 kg inactive mercury. Before injection, the radioisotope mercury was mixed with non radioisotope mercury in a bath to obtain a suitable injection aliquots and standard references. Calibration curve, which was derived from two stage dilution processes taken from standard references, was used to examine degree of mixing between radioisotope and non radioisotope mercury and it was also used in weight calculation of non radioisotope mercury in electrolytic cell. Injection was carried out simply by pouring the injection aliquots into the flowing mercury at the inlet side of the cell. Mercury samples from the cells were extracted at regular time intervals and filled into vials for counting. This was done for the primary conformation of the completeness of mixing of the tracer with the non radioisotope mercury in each cell. When complete mixing is achieved, the unknown quantity of mercury in each cell was calculated based on mass balance principle. From the calculation the weight of mercury in each electrolytic cell was not the same and maximum error of measurement obtained from this method is 2.48 %. Compared to gravimetrically error

  11. Simpler and More Accurate: Weighing the Mercury in Electrolytic Cells by Radiotracer Dilution Method

    International Nuclear Information System (INIS)

    Sugiharto; Santoso, S.B.; Santoso, G.B.

    2010-01-01

    Weight of mercury in electrolytic cell of soda industry is usually measured gravimetrically, which is typical labor work in character. Error sources of the gravimetric method might have come from the fact that some mercury's are usually trapped in the cell due to complicated structure of electrolytic cell. This cause unknown errors. In addition, formation of amalgam at the cathode may cause a further uncertainty in the measurement. Total error from gravimetric method is 4% on average. Radiotracer dilution method provides advantages either for simplification of procedure and reduction of measurement error. In this experiment radioisotope mercury 203 Hg, which was prepared in nuclear reactor was used to examine 13 of 14 electrolytic cells of soda plant. Each electrolytic cell was designed containing approximately 700 kg inactive mercury. Before injection, the radioisotope mercury was mixed with non radioisotope mercury in a bath to obtain a suitable injection aliquots and standard references. Calibration curve, which was derived from two stage dilution processes taken from standard references, was used to examine degree of mixing between radioisotope and non radioisotope mercury and it was also used in weight calculation of non radioisotope mercury in electrolytic cell. Injection was carried out simply by pouring the injection aliquots into the flowing mercury at the inlet side of the cell. Mercury samples from the cells were extracted at regular time intervals and filled into vials for counting. This was done for the primary conformation of the completeness of mixing of the tracer with the non radioisotope mercury in each cell. When complete mixing is achieved, the unknown quantity of mercury in each cell was calculated based on mass balance principle. From the calculation the weight of mercury in each electrolytic cell was not the same and maximum error of measurement obtained from this method is 2.48 %. Compared to gravimetrically error mentioned above, it was

  12. An isotope-dilution standard GC/MS/MS method for steroid hormones in water

    Science.gov (United States)

    Foreman, William T.; Gray, James L.; ReVello, Rhiannon C.; Lindley, Chris E.; Losche, Scott A.

    2013-01-01

    An isotope-dilution quantification method was developed for 20 natural and synthetic steroid hormones and additional compounds in filtered and unfiltered water. Deuterium- or carbon-13-labeled isotope-dilution standards (IDSs) are added to the water sample, which is passed through an octadecylsilyl solid-phase extraction (SPE) disk. Following extract cleanup using Florisil SPE, method compounds are converted to trimethylsilyl derivatives and analyzed by gas chromatography with tandem mass spectrometry. Validation matrices included reagent water, wastewater-affected surface water, and primary (no biological treatment) and secondary wastewater effluent. Overall method recovery for all analytes in these matrices averaged 100%; with overall relative standard deviation of 28%. Mean recoveries of the 20 individual analytes for spiked reagent-water samples prepared along with field samples analyzed in 2009–2010 ranged from 84–104%, with relative standard deviations of 6–36%. Detection levels estimated using ASTM International’s D6091–07 procedure range from 0.4 to 4 ng/L for 17 analytes. Higher censoring levels of 100 ng/L for bisphenol A and 200 ng/L for cholesterol and 3-beta-coprostanol are used to prevent bias and false positives associated with the presence of these analytes in blanks. Absolute method recoveries of the IDSs provide sample-specific performance information and guide data reporting. Careful selection of labeled compounds for use as IDSs is important because both inexact IDS-analyte matches and deuterium label loss affect an IDS’s ability to emulate analyte performance. Six IDS compounds initially tested and applied in this method exhibited deuterium loss and are not used in the final method.

  13. Experimental substantiation of separation techniques of lead and uranium microamounts using isotopic dilution method as control method

    International Nuclear Information System (INIS)

    Agapova, A.A.; Shcherbinina, N.K.

    1983-01-01

    Methods,ensuring at low levels of contamination a high degree of lead and uranium microamount separation from solutions of geological samples, have been selected and subjected to the detailed testing. The method of isotope dilution, , combining high accuracy and sensitivity of determinations, is used as the main control methods, is used as the main control method. Using the method, processe es of uranium extpaction are traced, special attention is paid to the detailed description of lead extraction at all the stages of the methods selected. Opera ations of ion exchange for lead and uranium in microcolumns with the Bio-Rad r sin are considered, as well as operations of lead electrolytic separation. The chemical procedures suggested permit to solve one of the main methodical tasks f sample preparation, containing microgram amounts of lead and uranium, for high h-prcision measurement of their isotope composition using mass-spectrometric method

  14. Relationship between CT visual score and lung volume which is measured by helium dilution method and body plethysmographic method in patients with pulmonary emphysema

    International Nuclear Information System (INIS)

    Toyoshima, Hideo; Ishibashi, Masayoshi; Senju, Syoji; Tanaka, Hideki; Aritomi, Takamichi; Watanabe, Kentaro; Yoshida, Minoru

    1997-01-01

    We examined the relationship between CT visual score and pulmonary function studies in patients with pulmonary emphysema. Lung volume was measured using helium dilution method and body plethysmographic method. Although airflow obstruction and overinflation measured by helium dilution method did not correlate with CT visual score, CO diffusing capacity per alveolar volume (DL CO /V A ) showed significant negative correlation with CT visual score (r=-0.49, p CO /V A reflect pathologic change in pulmonary emphysema. Further, both helium dilution method and body plethysmographic method are required to evaluate lung volume of pulmonary emphysema because of its ventilatory unevenness. (author)

  15. a Borehole-Dilution Method for Quantifying Vertical Darcy Fluxes in the Hyporheic Zone

    Science.gov (United States)

    Augustine, S. D.; Annable, M. D.; Cho, J.

    2017-12-01

    The borehole dilution method has consistently and successfully been used for estimating local water fluxes, however, this method can be relatively labor intensive and expensive. The focus of this research is aimed at developing a low-cost, borehole dilution method for quantifying vertical water fluxes in the hyporheic zone at the surface-groundwater interface. This would allow for the deployment of multiple units within a targeted surface water body and thus produce high-resolution, spatially distributed data on the infiltration rates over a short period of time with minimal set-up requirements. The device consists of a 2-inch, inner diameter PVC pipe containing short, screened sections in its upper and lower segments. The working unit is driven into the sediment and acts as a continuous flow reactor creating a pathway between the subsurface pore-water and the overlying surface water where the presence of a hydraulic gradient facilitates vertical movement. We developed a simple electrode and tracer-injection system housed within the unit to inject and measure salt tracer concentrations at the desired intervals while monitoring and storing those measurements using open-source Arduino technology. Preliminary lab and field scale trials provided data that was fit to both zero and first order reaction rate functions for analysis. The field test was conducted over approximately one day within a wet retention basin. The initial results estimated a vertical Darcy flux of 113.5 cm/d. Additional testing over a range of expected Darcy fluxes will be presented along with an evaluation considering enhanced water flow due to the high hydraulic conductivity of the device.

  16. Method of phase space beam dilution utilizing bounded chaos generated by rf phase modulation

    Directory of Open Access Journals (Sweden)

    Alfonse N. Pham

    2015-12-01

    Full Text Available This paper explores the physics of chaos in a localized phase-space region produced by rf phase modulation applied to a double rf system. The study can be exploited to produce rapid particle bunch broadening exhibiting longitudinal particle distribution uniformity. Hamiltonian models and particle-tracking simulations are introduced to understand the mechanism and applicability of controlled particle diffusion. When phase modulation is applied to the double rf system, regions of localized chaos are produced through the disruption and overlapping of parametric resonant islands and configured to be bounded by well-behaved invariant tori to prevent particle loss. The condition of chaoticity and the degree of particle dilution can be controlled by the rf parameters. The method has applications in alleviating adverse space-charge effects in high-intensity beams, particle bunch distribution uniformization, and industrial radiation-effects experiments.

  17. Establishment and application of deuterium dilution method for measuring breast milk intake of Pakistani infants

    International Nuclear Information System (INIS)

    Bilal, R.

    1999-01-01

    This project will be a collaborative study between the Pakistan Institute for Nuclear Science and Technology (PINSTECH) and Department of Pediatrics, Pakistan Institute of Medical Sciences (PIMS). It may also involve the Polyclinic, Islamabad. Pediatricians who have had experience in lactation management clinic and hence breast-milk intake studies by conventional methods (test weighing) will be formally involved in the study. Human milk intake and growth performance of exclusively breast-fed infants will be monitored over the first six months of life. The deuterium dilution method will be used for measuring breast-milk intake and will be compared with the test weighing method. The growth of exclusively breast-fed children will be compared with the NCH growth standards. Records of illnesses that may lead to suboptimal growth will be kept. Episodes of diarrhoea, in particular, will be correlated with growth faltering. Acquisition of Helicobacter pylori detected by the use of the 13 C Urea breath test at three month intervals during the study period examined for relationships with diarrhoea. Thus, this study will not only provide preliminary data on breast-milk intake (based on a more accurate isotopic method as compared to test weighing) but also on the growth patterns of exclusively breast-fed infants. Further, information on the significance of Helicobacter pylori to infection with episodes of diarrhoeal infection and growth faltering. (author)

  18. 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

  19. Analysis of ochratoxin A in grapes, musts and wines by LC–MS/MS: First comparison of stable isotope dilution assay and diastereomeric dilution assay methods

    Energy Technology Data Exchange (ETDEWEB)

    Roland, Aurélie, E-mail: aurelie@nyseos.fr [Nyseos, 2 place Pierre Viala, Montpellier Cedex 1 34060 (France); Bros, Pauline, E-mail: pauline.bros@gmail.com [Institut Français de la Vigne et du Vin, UMT Qualinnov, 2 place Pierre Viala, Montpellier Cedex 1 34060 (France); Bouisseau, Anaïs, E-mail: anais.bouisseau@gmail.com [Nyseos, 2 place Pierre Viala, Montpellier Cedex 1 34060 (France); Institut des Biomolécules Max Mousseron, UMR-CNRS-5247, Universités Montpellier I and II, Place Eugène Bataillon, 34095 Montpellier (France); Cavelier, Florine, E-mail: florine@univ-montp2.fr [Institut des Biomolécules Max Mousseron, UMR-CNRS-5247, Universités Montpellier I and II, Place Eugène Bataillon, 34095 Montpellier (France); Schneider, Rémi, E-mail: remi.schneider@vignevin.com [Institut Français de la Vigne et du Vin, UMT Qualinnov, 2 place Pierre Viala, Montpellier Cedex 1 34060 (France)

    2014-03-01

    Highlights: • OTA extraction on immunoaffinity columns is not adapted for DIDA quantification. • The use of a labeled internal standard is compulsory to obtain reliable results. • SIDA and DIDA quantification approaches have been compared for the first time. Abstract: Ochratoxin A (OTA) exhibits potent nephrotoxic, carcinogenic and teratogenic effects and its maximum level in wines has been set to 2 μg L⁻¹ by regulation. Consequently, the analytical procedures for OTA determination in wines have to be both very sensitive and reliable. In this paper, we compared two quantification methods: the stable isotope dilution assay (SIDA) and the diastereomeric dilution assay (DIDA). For this purpose, non-natural analogues of OTA were synthesized: the labeled OTA (OTA-d₄) as a diastereomeric mixture for the SIDA and one non-natural OTA’s diastereomer (OTA-dia) for the DIDA. To quantify OTA in red grapes, musts or wines, the sample preparation was optimized using immunoaffinity column extraction and the analysis was performed by LC–MS/MS in Multiple Reaction Monitoring mode. A validation procedure in agreement with the International Organization of Vine and Wine recommendations was conducted. It appeared that SIDA quantification exhibited excellent sensitivity (LOD < 1 ng L⁻¹), accuracy (recovery = 98%), repeatability (RSD < 3%) and intermediate reproducibility (RSD < 4%) compared to quantification by DIDA. Indeed, DIDA method did not provide satisfactory results demonstrating that immunoaffinity extraction is exclusively selective for the natural OTA and not for its diastereomer, which therefore cannot be considered as a good internal standard for this particular method.

  20. Analysis of ochratoxin A in grapes, musts and wines by LC–MS/MS: First comparison of stable isotope dilution assay and diastereomeric dilution assay methods

    International Nuclear Information System (INIS)

    Roland, Aurélie; Bros, Pauline; Bouisseau, Anaïs; Cavelier, Florine; Schneider, Rémi

    2014-01-01

    Highlights: • OTA extraction on immunoaffinity columns is not adapted for DIDA quantification. • The use of a labeled internal standard is compulsory to obtain reliable results. • SIDA and DIDA quantification approaches have been compared for the first time. - Abstract: Ochratoxin A (OTA) exhibits potent nephrotoxic, carcinogenic and teratogenic effects and its maximum level in wines has been set to 2 μg L −1 by regulation. Consequently, the analytical procedures for OTA determination in wines have to be both very sensitive and reliable. In this paper, we compared two quantification methods: the stable isotope dilution assay (SIDA) and the diastereomeric dilution assay (DIDA). For this purpose, non-natural analogues of OTA were synthesized: the labeled OTA (OTA-d 4 ) as a diastereomeric mixture for the SIDA and one non-natural OTA’s diastereomer (OTA-dia) for the DIDA. To quantify OTA in red grapes, musts or wines, the sample preparation was optimized using immunoaffinity column extraction and the analysis was performed by LC–MS/MS in Multiple Reaction Monitoring mode. A validation procedure in agreement with the International Organization of Vine and Wine recommendations was conducted. It appeared that SIDA quantification exhibited excellent sensitivity (LOD −1 ), accuracy (recovery = 98%), repeatability (RSD < 3%) and intermediate reproducibility (RSD < 4%) compared to quantification by DIDA. Indeed, DIDA method did not provide satisfactory results demonstrating that immunoaffinity extraction is exclusively selective for the natural OTA and not for its diastereomer, which therefore cannot be considered as a good internal standard for this particular method

  1. New method of preparation of CaSO{sub 4}: Dy for ionizing radiation dosimetry; Nuevo metodo de preparacion del CaSO{sub 4}: Dy para dosimetria de radiacion ionizante

    Energy Technology Data Exchange (ETDEWEB)

    Roman L, J.; Rivera M, T.; Alarcon F, G.; Guzman M, J. [CICATA-IPN, 11500 Mexico D.F. (Mexico); Azorin N, J.; Sosa F, R. [UAM-I, 09340 Mexico D.F. (Mexico); Serrano F, A.K. [Hospital Juarez General de Mexico, 07760 Mexico D.F. (Mexico)]. e-mail: holand_jeos@hotmail.com

    2008-07-01

    In this work some results of the characterization of solid state materials exposed at a gamma radiation beam coming from a {sup 60} Co bomb for medical use are presented. These thermoluminescent dosemeters are prepared and proposed for the ionizing radiations dosimetry using the thermoluminescence method. The passive dosemeters of CaSO{sub 4}: Dy are developed in the polycrystalline powder form being used a new synthesis route by means of the precipitation method. To determine the sensibility of the pellets of CaSO{sub 4}: Dy before gamma radiation, these were exposed before a gamma radiation beam coming from a {sup 60} Co bomb. The morphological and structural characteristics were also studied and present two in this work. (Author)

  2. Multi-mycotoxin stable isotope dilution LC-MS/MS method for Fusarium toxins in beer.

    Science.gov (United States)

    Habler, Katharina; Gotthardt, Marina; Schüler, Jan; Rychlik, Michael

    2017-03-01

    A stable isotope dilution LC-MS/MS multi-mycotoxin method was developed for 12 different Fusarium toxins including modified mycotoxins in beer (deoxynivalenol-3-glucoside, deoxynivalenol, 3-acetyldeoxynivalenol, 15-acetyl-deoxynivalenol, HT2-toxin, T2-toxin, enniatin B, B1, A1, A, beauvericin and zearalenone). As sample preparation and purification of beer a combined solid phase extraction for trichothecenes, enniatins, beauvericin and zearalenone was firstly developed. The validation of the new method gave satisfying results: intra-day and inter-day precision and recoveries were 1-5%, 2-8% and 72-117%, respectively. In total, 61 different organic and conventional beer samples from Germany and all over the world were analyzed by using the newly developed multi-mycotoxin method. In summary, deoxynivalenol, deoxynivalenol-3-glucoside, 3-acetyldeoxynivaleneol and enniatin B were quantified in rather low contents in the investigated beer samples. None of the other monitored Fusarium toxins like 15-acetyldeoxynivalenol, HT2- and T2-toxin, zearalenone, enniatin B1, A1, A or beauvericin were detectable. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Applicability of isotopic dilution methods for determination of the zinc supplying capacity of some Indian soils

    International Nuclear Information System (INIS)

    Iyengar, B.R.V.; Deb, D.L.

    1975-01-01

    The applicability of the isotopic dilution methods to determine the zinc supplying capacity of some Indian soils belonging to three soil groups was studied using 65 Zn. In these soils 'L' values determined by the pot culture method and the 'E' values by equilibration in soil suspensions by the carrier free and carrier methods and using chemical extractants DTPA-CaCl 2 -NaOAc and EDTA-NH 4 OAc were compared. The 'L' values were significantly correlated with zinc uptake by maize and also with zinc extracted by a number of chemical extractants. The laboratory determinations 'E' values by isotopic exchange equilibria in soil suspension both with and without carrier zinc led to over estimates and gave grossly exggerated values of 'labile zinc' especially in alkaline and high zinc 'fixing' soils. The 'E' values determined in both DTPA-CaCl 2 -NaOAc and EDTA-NH 4 OAc correlated significantly with zinc uptake by maize. These values agreed well with 'L' values and 'available' zinc determined by chemical soil tests. (author)

  4. Preparation and LSC Standardization of ''89Sr (DNP) Using the CIEMAT/NIST Method; Preparacion del ''89Sr(DNP) y calibracion por centelleo liquido, mediante el metodo CIEMAT/NIST

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Barquero, L.; Los Arcos Merino, J. M.; Grau Malonda, A.

    1994-07-01

    A procedure for preparation of liquid scintillation counting samples of the strontium DNP complex, labelled with ''89Sr, is described, the chemical quench, the counting stability and spectral evolution of this compound is studied in six scintillators, Toluene, Toluene-alcohol, Dioxane-naphthalene, HiSafe II, Ultima- Gold and Instagel. The liquid scintillation standardization of 89Sr-DNP by the CIEMAT/NIST method, using HiSafe II and Ultima-Gold scintillators, has been carried out. The discrepancies between experimental and computed efficiencies are lower than 0.38% and 0.48%, respectively. The solution has been standardized in terms of activity concentration to an overall uncertainty of 0,38%. (Author) 10 refs.

  5. Mercury speciation analysis in seafood by species-specific isotope dilution: method validation and occurrence data

    Energy Technology Data Exchange (ETDEWEB)

    Clemens, Stephanie; Guerin, Thierry [Agence Nationale de Securite Sanitaire de l' Alimentation, Laboratoire de Securite des Aliments de Maisons-Alfort, Unite des Contaminants Inorganiques et Mineraux de l' Environnement, ANSES, Maisons-Alfort (France); Monperrus, Mathilde; Donard, Olivier F.X.; Amouroux, David [IPREM UMR 5254 CNRS - Universite de Pau et des Pays de l' Adour, Laboratoire de Chimie Analytique Bio-Inorganique et Environnement, Institut des Sciences Analytiques et de Physico-chimie pour l' Environnement et les Materiaux, Pau Cedex (France)

    2011-11-15

    Methylmercury (MeHg) and total mercury (THg) in seafood were determined using species-specific isotope dilution analysis and gas chromatography combined with inductively coupled plasma mass spectrometry. Sample preparation methods (extraction and derivation step) were evaluated on certified reference materials using isotopically enriched Hg species. Solid-liquid extraction, derivation by propylation and automated agitation gave excellent accuracy and precision results. Satisfactory figures of merit for the selected method were obtained in terms of limit of quantification (1.2 {mu}g Hg kg{sup -1} for MeHg and 1.4 {mu}g Hg kg{sup -1} for THg), repeatability (1.3-1.7%), intermediate precision reproducibility (1.5% for MeHg and 2.2% for THg) and trueness (bias error less than 7%). By means of a recent strategy based on accuracy profiles ({beta}-expectation tolerance intervals), the selected method was successfully validated in the range of approximately 0.15-5.1 mg kg{sup -1} for MeHg and 0.27-5.2 mg kg{sup -1} for THg. Probability {beta} was set to 95% and the acceptability limits to {+-}15%. The method was then applied to 62 seafood samples representative of consumption in the French population. The MeHg concentrations were generally low (1.9-588 {mu}g kg{sup -1}), and the percentage of MeHg varied from 28% to 98% in shellfish and from 84% to 97% in fish. For all real samples tested, methylation and demethylation reactions were not significant, except in one oyster sample. The method presented here could be used for monitoring food contamination by MeHg and inorganic Hg in the future to more accurately assess human exposure. (orig.)

  6. Viscosity of dilute suspensions of rodlike particles: A numerical simulation method

    Science.gov (United States)

    Yamamoto, Satoru; Matsuoka, Takaaki

    1994-02-01

    The recently developed simulation method, named as the particle simulation method (PSM), is extended to predict the viscosity of dilute suspensions of rodlike particles. In this method a rodlike particle is modeled by bonded spheres. Each bond has three types of springs for stretching, bending, and twisting deformation. The rod model can therefore deform by changing the bond distance, bond angle, and torsion angle between paired spheres. The rod model can represent a variety of rigidity by modifying the bond parameters related to Young's modulus and the shear modulus of the real particle. The time evolution of each constituent sphere of the rod model is followed by molecular-dynamics-type approach. The intrinsic viscosity of a suspension of rodlike particles is derived from calculating an increased energy dissipation for each sphere of the rod model in a viscous fluid. With and without deformation of the particle, the motion of the rodlike particle was numerically simulated in a three-dimensional simple shear flow at a low particle Reynolds number and without Brownian motion of particles. The intrinsic viscosity of the suspension of rodlike particles was investigated on orientation angle, rotation orbit, deformation, and aspect ratio of the particle. For the rigid rodlike particle, the simulated rotation orbit compared extremely well with theoretical one which was obtained for a rigid ellipsoidal particle by use of Jeffery's equation. The simulated dependence of the intrinsic viscosity on various factors was also identical with that of theories for suspensions of rigid rodlike particles. For the flexible rodlike particle, the rotation orbit could be obtained by the particle simulation method and it was also cleared that the intrinsic viscosity decreased as occurring of recoverable deformation of the rodlike particle induced by flow.

  7. Quantification of methane and nitrous oxide emissions from various waste treatment facilities by tracer dilution method

    Science.gov (United States)

    Mønster, Jacob; Rella, Chris; Jacobson, Gloria; Kjeldsen, Peter; Scheutz, Charlotte

    2013-04-01

    Urban activities generate solid and liquid waste, and the handling and aftercare of the waste results in the emission of various compounds into the surrounding environment. Some of these compounds are emitted as gasses into the atmosphere, including methane and nitrous oxide. Methane and nitrous oxide are strong greenhouse gases and are considered to have 25 and 298 times the greenhouse gas potential of carbon dioxide on a hundred years term (Solomon et al. 2007). Global observations of both gasses have shown increasing concentrations that significantly contribute to the greenhouse gas effect. Methane and nitrous oxide are emitted from both natural and anthropogenic sources and inventories of source specific fugitive emissions from the anthropogenic sources of methane and nitrous oxide of are often estimated on the basis of modeling and mass balance. Though these methods are well-developed, actual measurements for quantification of the emissions is a very useful tool for verifying the modeling and mass balance as well as for validation initiatives done for lowering the emissions of methane and nitrous oxide. One approach to performing such measurements is the tracer dilution method (Galle et al. 2001, Scheutz et al. 2011), where the exact location of the source is located and a tracer gas is released at this source location at a known flow. The ratio of downwind concentrations of the tracer gas and the methane and nitrous oxide gives the emissions rates of the greenhouse gases. This tracer dilution method can be performed using both stationary and mobile measurements and in both cases, real-time measurements of both tracer and quantified gas are required, placing high demands on the analytical detection method. To perform the methane and nitrous oxide measurements, two robust instruments capable of real-time measurements were used, based on cavity ring-down spectroscopy and operating in the near-infrared spectral region. One instrument measured the methane and

  8. A dilute-and-shoot flow-injection tandem mass spectrometry method for quantification of phenobarbital in urine.

    Science.gov (United States)

    Alagandula, Ravali; Zhou, Xiang; Guo, Baochuan

    2017-01-15

    Liquid chromatography/tandem mass spectrometry (LC/MS/MS) is the gold standard of urine drug testing. However, current LC-based methods are time consuming, limiting the throughput of MS-based testing and increasing the cost. This is particularly problematic for quantification of drugs such as phenobarbital, which is often analyzed in a separate run because they must be negatively ionized. This study examined the feasibility of using a dilute-and-shoot flow-injection method without LC separation to quantify drugs with phenobarbital as a model system. Briefly, a urine sample containing phenobarbital was first diluted by 10 times, followed by flow injection of the diluted sample to mass spectrometer. Quantification and detection of phenobarbital were achieved by an electrospray negative ionization MS/MS system operated in the multiple reaction monitoring (MRM) mode with the stable-isotope-labeled drug as internal standard. The dilute-and-shoot flow-injection method developed was linear with a dynamic range of 50-2000 ng/mL of phenobarbital and correlation coefficient > 0.9996. The coefficients of variation and relative errors for intra- and inter-assays at four quality control (QC) levels (50, 125, 445 and 1600 ng/mL) were 3.0% and 5.0%, respectively. The total run time to quantify one sample was 2 min, and the sensitivity and specificity of the method did not deteriorate even after 1200 consecutive injections. Our method can accurately and robustly quantify phenobarbital in urine without LC separation. Because of its 2 min run time, the method can process 720 samples per day. This feasibility study shows that the dilute-and-shoot flow-injection method can be a general way for fast analysis of drugs in urine. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  9. Precise determination of sodium in serum by simulated isotope dilution method of inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Yan Ying; Zhang Chuanbao; Zhao Haijian; Chen Wenxiang; Shen Ziyu; Wang Xiaoru; Chen Dengyun

    2007-01-01

    A new precise and accurate method for the determination of sodium in serum by inductively coupled plasma mass spectrometry (ICP-MS) was developed. Since 23 Na is the single isotope element, 27 Al is selected as simulated isotope of Na. Al is spiked into serum samples and Na standard solution. 23 Na/ 27 Al ratio in the Na standard solution is determined to assume the natural Na isotope ratio. The serums samples are digested by purified HNO 3 /H 2 O 2 and diluted to get about 0.6 μg·g -1 Al solutions, and the 23 Na/ 27 Al ratios of the serum samples are obtained to calculate the accurate Na concentrations basing on the isotope dilution method. When the simulated isotope dilution method of ICP-MS is applied and Al is selected as the simulated isotope of Na, the precise and accurate Na concentrations in the serums are determined. The inter-day precision of CV<0.13% for one same serum sample is obtained during 3 days 4 measurements. The spike recoveries are between 99.69% and 100.60% for 4 different serum samples and 3 days multi-measurements. The results of measuring standard reference materials of serum sodium are agree with the certified value. The relative difference between 3 days is 0.22%-0.65%, and the relative difference in one bottle is 0.15%-0.44%. The ICP-MS and Al simulated isotope dilution method is proved to be not only precise and accurate, but also quick and convenient for measuring Na in serum. It is promising to be a reference method for precise determination of Na in serum. Since Al is a low cost isotope dilution reagent, the method is possible to be widely applied for serum Na determination. (authors)

  10. Body composition measures of obese adolescents by the deuterium oxide dilution method and by bioelectrical impedance

    Directory of Open Access Journals (Sweden)

    C.M.M. Resende

    2011-11-01

    Full Text Available The objectives of the present study were to describe and compare the body composition variables determined by bioelectrical impedance (BIA and the deuterium dilution method (DDM, to identify possible correlations and agreement between the two methods, and to construct a linear regression model including anthropometric measures. Obese adolescents were evaluated by anthropometric measures, and body composition was assessed by BIA and DDM. Forty obese adolescents were included in the study. Comparison of the mean values for the following variables: fat body mass (FM; kg, fat-free mass (FFM; kg, and total body water (TBW; % determined by DDM and by BIA revealed significant differences. BIA overestimated FFM and TBW and underestimated FM. When compared with data provided by DDM, the BIA data presented a significant correlation with FFM (r = 0.89; P < 0.001, FM (r = 0.93; P < 0.001 and TBW (r = 0.62; P < 0.001. The Bland-Altman plot showed no agreement for FFM, FM or TBW between data provided by BIA and DDM. The linear regression models proposed in our study with respect to FFM, FM, and TBW were well adjusted. FFM obtained by DDM = 0.842 x FFM obtained by BIA. FM obtained by DDM = 0.855 x FM obtained by BIA + 0.152 x weight (kg. TBW obtained by DDM = 0.813 x TBW obtained by BIA. The body composition results of obese adolescents determined by DDM can be predicted by using the measures provided by BIA through a regression equation.

  11. Atmospheric modeling to assess wind dependence in tracer dilution method measurements of landfill methane emissions.

    Science.gov (United States)

    Taylor, Diane M; Chow, Fotini K; Delkash, Madjid; Imhoff, Paul T

    2018-03-01

    The short-term temporal variability of landfill methane emissions is not well understood due to uncertainty in measurement methods. Significant variability is seen over short-term measurement campaigns with the tracer dilution method (TDM), but this variability may be due in part to measurement error rather than fluctuations in the actual landfill emissions. In this study, landfill methane emissions and TDM-measured emissions are simulated over a real landfill in Delaware, USA using the Weather Research and Forecasting model (WRF) for two emissions scenarios. In the steady emissions scenario, a constant landfill emissions rate is prescribed at each model grid point on the surface of the landfill. In the unsteady emissions scenario, emissions are calculated at each time step as a function of the local surface wind speed, resulting in variable emissions over each 1.5-h measurement period. The simulation output is used to assess the standard deviation and percent error of the TDM-measured emissions. Eight measurement periods are simulated over two different days to look at different conditions. Results show that standard deviation of the TDM- measured emissions does not increase significantly from the steady emissions simulations to the unsteady emissions scenarios, indicating that the TDM may have inherent errors in its prediction of emissions fluctuations. Results also show that TDM error does not increase significantly from the steady to the unsteady emissions simulations. This indicates that introducing variability to the landfill emissions does not increase errors in the TDM at this site. Across all simulations, TDM errors range from -15% to 43%, consistent with the range of errors seen in previous TDM studies. Simulations indicate diurnal variations of methane emissions when wind effects are significant, which may be important when developing daily and annual emissions estimates from limited field data. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Using the tracer-dilution discharge method to develop streamflow records for ice-affected streams in Colorado

    Science.gov (United States)

    Capesius, Joseph P.; Sullivan, Joseph R.; O'Neill, Gregory B.; Williams, Cory A.

    2005-01-01

    Accurate ice-affected streamflow records are difficult to obtain for several reasons, which makes the management of instream-flow water rights in the wintertime a challenging endeavor. This report documents a method to improve ice-affected streamflow records for two gaging stations in Colorado. In January and February 2002, the U.S. Geological Survey, in cooperation with the Colorado Water Conservation Board, conducted an experiment using a sodium chloride tracer to measure streamflow under ice cover by the tracer-dilution discharge method. The purpose of this study was to determine the feasibility of obtaining accurate ice-affected streamflow records by using a sodium chloride tracer that was injected into the stream. The tracer was injected at two gaging stations once per day for approximately 20 minutes for 25 days. Multiple-parameter water-quality sensors at the two gaging stations monitored background and peak chloride concentrations. These data were used to determine discharge at each site. A comparison of the current-meter streamflow record to the tracer-dilution streamflow record shows different levels of accuracy and precision of the tracer-dilution streamflow record at the two sites. At the lower elevation and warmer site, Brandon Ditch near Whitewater, the tracer-dilution method overestimated flow by an average of 14 percent, but this average is strongly biased by outliers. At the higher elevation and colder site, Keystone Gulch near Dillon, the tracer-dilution method experienced problems with the tracer solution partially freezing in the injection line. The partial freezing of the tracer contributed to the tracer-dilution method underestimating flow by 52 percent at Keystone Gulch. In addition, a tracer-pump-reliability test was conducted to test how accurately the tracer pumps can discharge the tracer solution in conditions similar to those used at the gaging stations. Although the pumps were reliable and consistent throughout the 25-day study period

  13. Determination of endogenous manganese excretion in broiler chicks by an isotope-dilution method

    International Nuclear Information System (INIS)

    Weigand, E.; Kirchgessner, M.; Kilic, A.

    1988-01-01

    A tracer study with broiler chicks was conducted to determine endogenous Mn excretion in response to graded levels of dietary Mn supply by the isotope-dilution method. Starting with 46 day-old chicks, low-Mn diets were fed for 12 days before 8 chicks were slaughtered for assessing the intial Mn status and 38 chicks each were given an intramuscular injection of 555 kBq 54 Mn. Four groups of six birds each were fed, one bird per cage, diets containing 2.8, 9.1, 25.8, and 59.7 ppm Mn for 16 days before slaughter and carcass analyses. Two groups of 7 birds were fed the diets with 9.1 and 25.8 ppm Mn for 8 days. Mn supply significantly affected 54 Mn excretion activity of distribution among various body organs, especially the liver. The specific activity of Mn in excreta and in whole-body declined exponentially with time and differed between groups. Endogenous Mn in excreta was estimated on the basis that the specific activity of excreta Mn from day 9 to 12 and day 13 to 16 was reflected, on the average, by that of liver Mn on day 10 and 14, respectively. It averaged in the order of increasing Mn supply 12.5 vs. 12.0; 7.7 vs. 8.5; 3.9 vs. 4.3, and 2.0 vs. 2.3% of total excreta Mn. Total Mn excretion from day 9 to 16 averaged 88.9, 95.0, 97.9. and 98.9% of Mn intake. (author)

  14. Comparison between isotope dilution and activation analysis as a method for determining the macro content of mercury

    International Nuclear Information System (INIS)

    Soedyartomo; Sunoko, S.R.

    1975-01-01

    It is true that the mercury content in the environment should be measured accurately because of its toxicity even at levels of microgram order. The assessment of hazards due to environmental contamination with mercury is based on the results of the metal analysis in a number of different samples. Consequently, the study of the character of analytical methods used, i.e. their accuracy, precision, sensitivity, etc. is essential. A brief description on the microanalysis methods of mercury as given. The discussion of the results obtained from analysing some sludge and water by means of isotope dilution and destructive thermal neutron activation analysis is also presented. It is found that both methods are suitable for routine work. It can be concluded that the isotope dilution method has some advantages. It is more simple, more sensitive, more rapid, and has lower radiation hazard. (author)

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

    DEFF Research Database (Denmark)

    Veng, Torben; Skettrup, Torben

    1997-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2002-12-01

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

  17. Error analysis of isotope dilution mass spectrometry method with internal standard

    International Nuclear Information System (INIS)

    Rizhinskii, M.W.; Vitinskii, M.Y.

    1989-02-01

    The computation algorithms of the normalized isotopic ratios and element concentration by isotope dilution mass spectrometry with internal standard are presented. A procedure based on the Monte-Carlo calculation is proposed for predicting the magnitude of the errors to be expected. The estimation of systematic and random errors is carried out in the case of the certification of uranium and plutonium reference materials as well as for the use of those reference materials in the analysis of irradiated nuclear fuels. 4 refs, 11 figs, 2 tabs

  18. Comparison of isotope dilution and excretion methods for determining the half-life of ascorbic acid in the guinea pig

    International Nuclear Information System (INIS)

    Kipp, D.E.; Rivers, J.M.

    1984-01-01

    The half-life of ascorbic acid (AA) in guinea pigs was investigated by the isotope dilution and excretion methods. The dilution method measures [1-14C]AA disappearance from the plasma, whereas the excretion method measures the elimination of [1-14C]AA and the metabolites from the body. Two groups of animals underwent both isotope studies in reverse order. Animals were conditioned to the experimental procedures and fed 2.5 mg AA/100 g body weight orally to maintain a daily intake of the vitamin independent of food consumption. The two isotope procedures imposed similar stress on the animals, as determined by plasma cortisol levels and body weight changes. The AA half-life calculations of the rapidly exchangeable pool by the isotope dilution method yielded values of 1.23 and 0.34 hours for the two groups, respectively. The half-life of the slowly exchangeable pool for the two groups was 60.2 and 65.8 hours, respectively. The half-life of AA in the rapidly exchangeable pool, as measured by the excretion studies, was 4.57-8.75 hours. For the slowly exchangeable pool, it was 146-149 hours. The longer half-life of both pools obtained with the excretion method indicates that the isotope is disappearing from the plasma more rapidly than it is being excreted. This suggests that a portion of the [1-14C]AA leaving the plasma is removed to a body pool that is not sampled by the isotope excretion method

  19. A radioactive tracer dilution method to determine the mass of molten salt

    International Nuclear Information System (INIS)

    Lei Cao; Jarrell, Josh; Hardtmayer, D.E.; White, Susan; Herminghuysen, Kevin; Kauffman, Andrew; Sanders, Jeff; Li, Shelly

    2017-01-01

    A new technique for molten salt mass determination, termed radioactive tracer dilution, that uses 22 Na as a tracer was validated at bench scale. It has been a challenging problem to determine the mass of molten salt in irregularly shaped containers, where a highly radioactive, high-temperature molten salt was used to process nuclear spent/used fuel during electrochemical recycling (pyro-processing) or for coolant/fuel salt from molten salt reactors. A radioactive source with known activity is dissolved into the salt. After a complete mixture, a small amount of the salt is sampled and measured in terms of its mass and radioactivity. By finding the ratio of the mass to radioactivity, the unknown salt mass in the original container can be precisely determined. (author)

  20. Accuracy of some routine method used in clinical chemistry as judged by isotope dilution-mass spectrometry

    International Nuclear Information System (INIS)

    Bjoerkhem, I.; Bergman, A.; Falk, O.; Kallner, A.; Lantto, O.; Svensson, L.; Akerloef, E.; Blomstrand, R.

    1981-01-01

    Serum from patients was pooled, filtered, dispensed, and frozen. This pooled specimen was used for accuracy control in 64 participating laboratories in Sweden. Mean values (state-of-the-art values) were obtained for creatinine, cholesterol, glucose, urea, uric acid, and cortisol. These values were compared with values obtained with highly accurate reference methods based on isotope dilution-mass spectrometry. Differences were marked in the case of determination of creatinine and cortisol. Concerning the other components, the differences between the state-of-the-art value and the values obtained with the reference methods were negligible. Moreover, the glucose oxidase and the oxime methods for determination of glucose and urea were found to give significantly lower values than the hexokinase and urease methods, respectively. Researchers conclude that methods with a higher degree of accuracy are required for routine determination of creatinine and cortisol

  1. The study on effect of zeolite on nitrogen use efficiency of corn by 15N-isotope dilution method

    International Nuclear Information System (INIS)

    Li Changhong; Li Huaxing; Zhang Xinming; Liu Yuanjin

    2002-01-01

    A pot experiment was carried out to study the effect of natural zeolite on nitrogen use efficiency of corn by using 15 N-isotope dilution method. The results showed that application of zeolite could improve the corn growth and enhance the biomass of the corn seedling. By using zeolite, nitrogen use efficiency (NUE) of corn was increased by 23.2%-33.1% as compared with no-zeolite treatment; and the residual nitrogen has no significant difference between zeolite treatment and no-zeolite treatment

  2. Biological nitrogen fixation in Crotalaria species estimated using the 15N isotope dilution method

    International Nuclear Information System (INIS)

    Samba, R.T.; Neyra, M.; Gueye, M.; Sylla, S.N.; Ndoye, I.; Dreyfus, B.

    2002-01-01

    Growing in Senegal by using 15 N direct isotope dilution technique. Two non-fixing plants, Senna obtusifolia and Senna occidentalis served as reference plants. The amount of nitrogen fixed two months after planting was obtained using the average of the two reference plants. The atom % 15 N excess in the Crotalaria species was significantly lower than that of the reference plants, indicating that significant nitrogen fixation occurred in the three plants. Significant differences were observed between the Crotalaria species; C. ochroleuca yielded more dry matter weight and total nitrogen than did C. perrottetti and C. retusa. The % nitrogen derived from atmosphere (%Ndfa) in leaves and stems was also higher in C. ochroleuca. There was no significant difference in %Ndfa in the whole plant between the three Crotalaria species (47% to 53%). In contrast, interspecific variability was observed based on the %Ndfa. C. ochroleuca significantly exhibited the higher amount of total nitrogen fixed, equivalent to 83 kg of nitrogen fixed per hectare. Based on these data, it was concluded that C. ochroleuca could be used in multiple cropping systems in Senegal for making more nitrogen available to other plants. (author)

  3. Post-mining deterioration of bauxite overburdens in Jamaica: storage methods or subsoil dilution?

    Science.gov (United States)

    Harris, Mark A.; Omoregie, Samson N.

    2008-03-01

    Rapid degradation of disturbed soil from a karst bauxite mine in Jamaica was recorded. Substantial macronutrient losses were incurred during a short (1 month) or a long (12 months) storage of the replaced topsoils during frequent wet/dry changes. The results suggested very high rates (>70% in the first year) of soil degradation from storage, alongside moderate rates (30%) within the same storage dump. However, higher levels of soil organic matter (SOM) were indicated just below the surface, compared with the surface horizons. It was unlikely that under a high leaching humid tropical rainfall regime, natural degradation processes could have re-emplaced such material firmly intact in the 15-30 cm zone. It was therefore concluded that these SOM anomalies were due to mechanical dilution of surface soil with subsoil material during overburden removal and emplacement rather than from long storage. Increasing the soil organic content during storage could be one corrective approach. However, it is far less costly to exercise greater care to apply more precise overburden removal and emplacement techniques initially, than it is to correct the results of topsoil contamination with subsoil. Although this study was limited to one mine, in the context of imminent large-scale mining expansion and current practices, further investigations are needed to accurately ascertain the proportion of similar subsoil contamination in other bauxite-mined sites.

  4. Use of 15N dilution method for screening soybean lines with high yield and high nitrogen fixation ability

    International Nuclear Information System (INIS)

    Li Haixian; Li Xinmin; Danso, S.K.A.

    1998-01-01

    15 N dilution method was used for screening soybean lines with high nitrogen fixation ability. Screened lines 1005, 8502, 2096, 943, 1454 and Dongnong-42 have high nitrogen fixation ability with their % Ndfa of about 70%. 1454 and 1555 are both high yield and high nitrogen fixation lines. The ability of nitrogen fixation was not related to the yield, but related to maturing time. The cultivars with different maturing time have different levels of nitrogen fixation ability. The longer the maturing period is, the greater the ability of nitrogen fixation it has. There were ten cultivars or lines used in the test of 1992 and 1994. Although the weather condition were greatly different between the two years the results of seven cultivars or lines were the same, indicating that nitrogen fixation ability of the soybean is stable with years. Using 15 N dilution method to estimate nitrogen fixation ability of soybean is reliable, however, the % Ndfa of lines 8502 and 2096 increased by 19% in 1994, a rainy year, indicating that a change in % Ndfa with a few varieties maybe caused by weather

  5. Quantification of Nitrous Oxide from Fugitive Emissions by Tracer Dilution Method using a Mobile Real-time Nitrous Oxide Analyzer

    Science.gov (United States)

    Mønster, J.; Rella, C.; Jacobson, G. A.; He, Y.; Hoffnagle, J.; Scheutz, C.

    2012-12-01

    Nitrous oxide is a powerful greenhouse gas considered 298 times stronger than carbon dioxide on a hundred years term (Solomon et al. 2007). The increasing global concentration is of great concern and is receiving increasing attention in various scientific and industrial fields. Nitrous oxide is emitted from both natural and anthropogenic sources. Inventories of source specific fugitive nitrous oxide emissions are often estimated on the basis of modeling and mass balance. While these methods are well-developed, actual measurements for quantification of the emissions can be a useful tool for verifying the existing estimation methods as well as providing validation for initiatives targeted at lowering unwanted nitrous oxide emissions. One approach to performing such measurements is the tracer dilution method (Galle et al. 2001), in which a tracer gas is released at the source location at a known flow. The ratio of downwind concentrations of both the tracer gas and nitrous oxide gives the ratios of the emissions rates. This tracer dilution method can be done with both stationary and mobile measurements; in either case, real-time measurements of both tracer and analyte gas is required, which places high demands on the analytical detection method. To perform the nitrous oxide measurements, a novel, robust instrument capable of real-time nitrous oxide measurements has been developed, based on cavity ring-down spectroscopy and operating in the near-infrared spectral region. We present the results of the laboratory and field tests of this instrument in both California and Denmark. Furthermore, results are presented from measurements using the mobile plume method with a tracer gas (acetylene) to quantify the nitrous oxide and methane emissions from known sources such as waste water treatment plants and composting facilities. Nitrous oxide (blue) and methane (yellow) plumes downwind from a waste water treatment facility.

  6. Dynamic determination of kinetic parameters for the interaction between polypeptide hormones and cell-surface receptors in the perfused rat liver by the multiple-indicator dilution method

    International Nuclear Information System (INIS)

    Sato, H.; Sugiyama, Y.; Sawada, Y.; Iga, T.; Sakamoto, S.; Fuwa, T.; Hanano, M.

    1988-01-01

    Hepatic elimination of epidermal growth factor (EGF) via receptor-mediated endocytosis was studied by a multiple-indicator dilution method in the isolated perfused rat liver, in which cell polarity and spatial organization are maintained. In this method EGF was given with inulin, an extracellular reference, as a bolus into the portal vein, and dilution curves of both compounds in the hepatic vein effluent were analyzed. Analysis of the dilution curve for EGF, compared with that for somatostatin, which showed no specific binding to isolated liver plasma membranes, resulted as follows: (i) both extraction ratio and distribution volume of 125 I-labeled EGF decreased as the injected amount of unlabeled EGF increased; (ii) the ratio plot of the dilution curve for EGF exhibited an upward straight line initially for a short period of time, whereas the ratio plot of somatostatin gradually decreased. The multiple-indicator dilution method was used for other peptides also. Insulin and glucagon, known to have hepatocyte receptors, behaved similarly to EGF in shape of their ratio plots. The kinetic parameters calculated by this analysis were comparable with reported values obtained by in vitro direct binding measurements at equilibrium using liver homogenates. They conclude that the multiple-indicator dilution method is a good tool for analyzing the dynamics of peptide hormones-cell-surface receptor interaction under a condition in which spatial architecture of the liver is maintained

  7. Sub-stoichiometric isotope dilution analysis method for the determination of iodine in common salts using iodine-131 tracer

    International Nuclear Information System (INIS)

    Singh, Vivek; Garg, A.N.

    1994-01-01

    A sub-stoichiometric isotope dilution analysis (SIDA) method was developed for the determination of iodine in different brands of common salts. An aqueous salt solution containing 131 I tracer and NaI as carrier is oxidized by tartaric acid and KIO 3 and the liberated iodine is extracted with CCl 4 . To the extract an aqueous solution of AgNO 3 is added in substoichiometric amount to obtain a colloidal solution of AgI. On adding sodium thiosulfate solution, the NaI so formed passes into aqueous solution, which is then counted. Several different brands of salt were analysed. The method is especially suitable for the determination of microgram amounts of iodide in the presence of excess of chloride. (Author)

  8. [Clinical signification of a modified dilution method (MDM) for blood loss assessment in the cases of nonvariceal upper gastrointestinal bleeding].

    Science.gov (United States)

    Geogiev, G; Shishenkov, M; Ninov, B; Dosheva, I

    2006-01-01

    The aim of this study was to compare the modified dilution method (MDM) for in vivo bloodless assessment with the accepted in the clinical practice methods. We measured 148 blood samples from 134 patients with nonvariceal upper gastrointestinal bleeding (NUGB) and 21 blood samples from healthy persons as a negative control. In the randomized group of 53 patients with NUGB we compared accuracy of the blood loss determination by means of erythrocyte mass loss (estimated with MDM), Allgower-Burri index and American College of Surgeon Index (ACSI). The obtained results give us a reason to recommend a combination between American College of Surgeon classification for blood loss in patients with NUGB and a parallel measurement of the MDM values.

  9. In vitro susceptibility of filamentous fungi to copper nanoparticles assessed by rapid XTT colorimetry and agar dilution method.

    Science.gov (United States)

    Ghasemian, E; Naghoni, A; Tabaraie, B; Tabaraie, T

    2012-12-01

    Metal nanoparticles and their uses in various aspects have recently drawn a great deal of attention. One of the major applications is that it can be used as an antimicrobial agent. They can be considered in approaches targeted to decrease the harms caused by microorganisms, specifically fungi, threatening the medical and industrial areas. The aim of this study was to investigate the antifungal activity of synthesized copper nanoparticles (CuNPs) against four filamentous fungi including Alternaria alternata, Aspergillus flavus, Fusarium solani, and Penicillium chrysogenum. Zerovalent copper nanoparticles of mean size 8nm were synthesized by inert gas condensation (IGC) method. The antifungal activity of these synthesized copper nanoparticles was measured against selected fungi by using two different techniques including agar dilution method and XTT reduction assay. The minimal inhibitory concentrations (MICs) for copper nanoparticles by agar dilution method were less or equal to 40mg/L for P. chrysogenum, less or equal to 60mg/L for A. alternata, less or equal to 60mg/L for F. solani, and less or equal to 80mg/L for A. flavus. And also MICs obtained by XTT reduction assay ranged from 40 to 80mg/L. Our data demonstrated that the copper nanoparticles inhibited fungal growth, but the fungal sensitivity to copper nanoparticles varies depending on the fungal species. Therefore, it is advisable that the minimal inhibitory concentrations (MICs) be examined before using these compounds. It is hoped that, in future, copper nanoparticles could replace some antifungal agents, making them applicable to many different medical devices and antimicrobial control system. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  10. Application and validation of isotope dilution method (IDM) for predicting bioavailability of hydrophobic organic contaminants in soil.

    Science.gov (United States)

    Wang, Jie; Taylor, Allison; Schlenk, Daniel; Gan, Jay

    2018-05-01

    Risk assessment of hydrophobic organic contaminants (HOCs) using the total chemical concentration following exhaustive extraction may overestimate the actual availability of HOCs to non-target organisms. Existing methods for estimating HOC bioavailability in soil have various operational limitations. In this study, we explored the application of isotope dilution method (IDM) to quantify the accessible fraction (E) of DDTs and PCBs in both historically-contaminated and freshly-spiked soils. After addition of 13 C or deuterated analogues to a soil sample, the phase distribution of isotope-labeled and native chemicals reached an apparent equilibrium within 48 h of mixing. The derived E values in the three soils ranged from 0.19 to 0.82, depending on the soil properties and also the contact time of HOCs (i.e., aging). The isotope dilution method consistently predicted greater accumulation into earthworm (Eisenia fetida) than that by polyethylene (PE) or solid phase microextraction (SPME) sampler, likely because desorption in the gut enhanced bioavailability of soil-borne HOCs. A highly significant linear regression (R 2  = 0.91) was found between IDM and 24-h Tenax desorption, with a slope statistically identical to 1. The IDM-derived accessible concentration (C e ) was further shown to accurately predict tissue residues in earthworm exposed in the same soils. Given the relatively short duration and simple steps, IDM has the potential to be readily adopted for measuring HOC bioaccessibility in soil and for improving risk assessment and evaluation of remediation efficiency. Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. Assay of cortisol with a radioimmunoassay method calibrated by isotope dilution-mass spectrometry. A Nordic collaborative study

    International Nuclear Information System (INIS)

    Lantto, O.; Lindback, B.; Aakvaag, A.; Bjoerkhem, I.; Damkjaer-Nielsen, M.; Pomoell, U.M.; Helsinki University Hospital

    1983-01-01

    A reference method for serum cortisol, based on isotope dilution-mass spectrometry (ID-MS), was compared with a modified commercial RIA method. The modification solely concerned the calibration standards used in the RIA method. These were replaced by a series of human serum samples, in which the concentration of cortisol had been determined by the reference ID-MS method. Samples were selected to cover the whole range of the standard curve. Serum samples from healthy, untreated subjects with cortisol concentrations 270-1134 nmol/l were analysed with the ID-MS calibrated RIA method in four laboratories, one in each of the four Nordic countries. Mean values based on results from all four laboratories were almost identical with the values obtained with the reference method. Serum samples from 11 patients with endocrine disorders with cortisol concentrations 31-916 nmol/l were analysed in three of the four laboratories. In three of the samples significant differences were observed between the values obtained with the ID-MS and the ID-MS calibrated RIA method. The value obtained with the ID-MS calibrated RIA was however always more accurate than the corresponding value obtained with RIA with the use of a commercial calibration standard. (author)

  12. Elements of a thermic method of preparing beta-sources with fused carriers, including strontium-90; Elements d'une methode thermique de preparation de sources beta avec des entraineurs fondus, y compris le strontium-90; Osnovy termicheskogo metoda prigotovleniya beta-istochnikov s plavlennymi nositelyami, vklyuchayushchimi strontsij-90; Bases de un metodo termico de preparacion de fuentes beta con portadores fundidos, incluido el estroncio-90

    Energy Technology Data Exchange (ETDEWEB)

    Bogdanov, N I; Zakharova, K P; Zimakov, P V; Kulichenko, V V

    1962-01-15

    comprises entre 100 et 1000{sup o}C, et expliquent le choix des parametres de base du procede employe. Ils precisent les fondements de la methode qui consiste a monter une preparation vitreuse contenant la quantite necessaire de {sup 90}Sr, sur des supports de forme et dimensions diverses en acier, ceramique et autres matieres. Enfin, les auteurs examinent les parametres de base qui permettent l'exploitation sure et sans danger des differents types de sources, et ils donnent des renseignements sur les sources de {sup 90}Sr preparees par la methode thermique. (author) [Spanish] Las fuentes de radiaciones ionizantes basadas en el radioisotopo {sup 90}Sr se utilizan ampliamente en la industria para los dispositivos y sistemas de control y regulacion automaticos. La preparacion de las fuentes consiste en la deshidratacion de una mezcla formada por una solucion radiactiva de nitrato de estroncio, y compuestos tales como el anhidrido borico, silice, alumina, etc. Por calentamiento de la mezcla deshidratada a temperaturas elevadas, se obtiene una masa fundida muy fluida que, una vez fria, da una masa vitrea que contiene la cantidad requerida de {sup 90}Sr. Los autores presentan datos y examinan los resultados obtenidos al estudiar la deshidratacion del sistema SrO - B{sub 2}O{sub 3}- SiO{sub 2} a temperaturas comprendidas entre 100 y 1000{sup o} C; tambien explican su eleccion de los parametros basicos del proceso tecnologico. Exponen en lineas generales un metodo que consiste en montar sobre acero, materiales ceramicos u otras sustancias, de distintas formas y dimensiones, una masa vitrea que contenga la cantidad requerida de {sup 90}Sr. La memoria estudia los parametros fundamentales para lograr una explotacion regular y segura de los distintos tipos de fuente, y presenta datos relativos y fuentes de {sup 90}Sr preparadas por el metodo termico. (author) [Russian] Istochniki ioniziruyushchikh izluchenij na osnove radioizotopa Sr''9''0 shiroko primenyayutsya v priborakh i skhemakh

  13. Isotope dilution/mass spectrometry of serum cholesterol with [3,4-13C]cholesterol: proposed definitive method

    International Nuclear Information System (INIS)

    Pelletier, O.; Wright, L.A.; Breckenridge, W.C.

    1987-01-01

    We describe a new gas-chromatographic/mass-spectrometric (GC/MS) isotope-dilution method for determination of serum cholesterol. The method has been fully optimized and documented to provide the high accuracy and precision expected for a Definitive Method. In the presence of [3,4- 13 C]cholesterol, cholesteryl esters in serum are hydrolyzed under optimum conditions and the entire cholesterol pool is extracted and derivatized to silyl ethers. The cholesterol derivatives are resolved from other sterols by gas-liquid chromatography on a fused silica column, and selected ions characteristic of cholesterol and the [3,4- 13 C]cholesterol are monitored with a GC/MS quandrupole system. We estimated the cholesterol content of samples by bracketing each sample with standards of comparable cholesterol concentration that also contained the [3,4- 13 C]cholesterol. The procedure was highly reproducible (CV less than 0.5%), better accuracy and precision being obtained with [3,4- 13 C]cholesterol than with heptadeuterated cholesterol. Mean values per gram of dry serum for one serum pool assayed by this method and that of the National Bureau of Standards differed by 0.5%. We conclude that the method satisfies the criteria for a Definitive Method

  14. Dilution Confusion: Conventions for Defining a Dilution

    Science.gov (United States)

    Fishel, Laurence A.

    2010-01-01

    Two conventions for preparing dilutions are used in clinical laboratories. The first convention defines an "a:b" dilution as "a" volumes of solution A plus "b" volumes of solution B. The second convention defines an "a:b" dilution as "a" volumes of solution A diluted into a final volume of "b". Use of the incorrect dilution convention could affect…

  15. Isotope-dilution gas chromatography-mass spectrometry method for the analysis of hydroxyurea.

    Science.gov (United States)

    Garg, Uttam; Scott, David; Frazee, Clint; Kearns, Gregory; Neville, Kathleen

    2015-06-01

    Hydroxyurea is used in the treatment of various malignancies and sickle cell disease. There are limited studies on the pharmacokinetics of hydroxyurea, particularly in pediatric patients. An accurate, precise, and sensitive method is needed to support such studies and to monitor therapeutic adherence. We describe a novel gas chromatography-mass spectrometry (GC-MS) method for the determination of hydroxyurea concentration in plasma using stable labeled hydroxyurea C N2 as an internal standard. The method involved an organic extraction followed by the preparation of trimethylsilyl (TMS) derivatives of hydroxyurea for GC-MS selected ion-monitoring analysis. The following mass-to-charge (m/z) ratio ions for silated hydroxyurea and hydroxyurea C N2 were monitored: hydroxyurea-quantitative ion 277, qualifier ions 292 and 249; hydroxyurea C N2-quantitative ion 280, qualifier ion 295. This method was evaluated for reportable range, accuracy, within-run and between-run imprecisions, and limits of quantification. The reportable range for the method was 0.1-100 mcg/mL. All results were accurate within an allowable error of 15%. Within-run and between-run imprecisions were hydroxyurea described here is accurate, sensitive, precise, and robust. Its characteristics make the method suitable for supporting pharmacokinetic studies and/or clinical therapeutic monitoring.

  16. Determination of niobium in rocks by an isotope dilution spectrophotometric method

    Science.gov (United States)

    Greenland, L.P.; Campbell, E.Y.

    1970-01-01

    Rocks and minerals are fused with sodium peroxide in the presence of carrierfree 95Nb. The fusion cake is leached with water and the precipitate dissolved in hydrofluoric-sulfuric acid mixture. Niobium is extracted into methyl isobutyl ketone and further purified by ion exchange. The amount of niobium is determined spectrophotometrically with 4-(2-pyridylazo)-resorcinol, and the chemical yield of the separations determined by counting 95Nb. This procedure is faster and less sensitive to interferences than previously proposed methods for determining niobium in rocks.The high purity of the separated niobium makes the method applicable to nearly all matrices. ?? 1970.

  17. Experimental design-based isotope-dilution SPME-GC/MS method development for the analysis of smoke flavouring products.

    Science.gov (United States)

    Giri, Anupam; Zelinkova, Zuzana; Wenzl, Thomas

    2017-12-01

    For the implementation of Regulation (EC) No 2065/2003 related to smoke flavourings used or intended for use in or on foods a method based on solid-phase micro extraction (SPME) GC/MS was developed for the characterisation of liquid smoke products. A statistically based experimental design (DoE) was used for method optimisation. The best general conditions to quantitatively analyse the liquid smoke compounds were obtained with a polydimethylsiloxane/divinylbenzene (PDMS/DVB) fibre, 60°C extraction temperature, 30 min extraction time, 250°C desorption temperature, 180 s desorption time, 15 s agitation time, and 250 rpm agitation speed. Under the optimised conditions, 119 wood pyrolysis products including furan/pyran derivatives, phenols, guaiacol, syringol, benzenediol, and their derivatives, cyclic ketones, and several other heterocyclic compounds were identified. The proposed method was repeatable (RSD% <5) and the calibration functions were linear for all compounds under study. Nine isotopically labelled internal standards were used for improving quantification of analytes by compensating matrix effects that might affect headspace equilibrium and extractability of compounds. The optimised isotope dilution SPME-GC/MS based analytical method proved to be fit for purpose, allowing the rapid identification and quantification of volatile compounds in liquid smoke flavourings.

  18. An Evaluation Method for the Suppression of Pathogenic Fusarium oxysporum by Soil Microorganisms Using the Dilution Plate Technique.

    Science.gov (United States)

    Mitsuboshi, Masahiro; Kioka, Yuuzou; Noguchi, Katsunori; Asakawa, Susumu

    2016-09-29

    Soil-borne diseases caused by pathogenic microorganisms are one of the main factors responsible for the decline in crop yields in farmlands. Pathogenic Fusarium oxysporum causes serious damage to various crops, and, thus, a feasible diagnostic method for soil-borne diseases is required. We herein examined a simple method to evaluate the suppressiveness of soil microorganisms against a pathogen by co-cultivating indigenous soil microorganisms and a pathogenic fungus (F. oxysporum f. sp. spinaciae). We inoculated F. oxysporum onto the center of agar medium plates mixed with a dilution series of a suspension of organic fertilizers or soil. After an approximately one-week cultivation, the growth degree of F. oxysporum was estimated based on the size of the colonies that formed on the plates. The growth degree of F. oxysporum significantly differed among the organic fertilizers tested, indicating the usefulness of the method for evaluating suppressiveness by organic fertilizers. Differences in the growth degrees of F. oxysporum were associated with the incidence of disease in spinach on soil treated with organic fertilizers and inoculated with a pathogenic F. oxysporum strain. These results suggested that this method provides some useful information on the suppressiveness of organic fertilizers and soil against Fusarium wilt.

  19. Study on cardiac output in children with orthostatic disturbances measured by the external dilution method with a radioisotope

    Energy Technology Data Exchange (ETDEWEB)

    Hattori, K [Nippon Medical School, Tokyo

    1975-04-01

    As one of the studies on circulation dynamics which possibly contributed to orthostatic disturbance, application to children of the external measurement of cardiac output with /sup 131/I labeled human serum albumin was examined. The effect of orthostatic load was then studied by this method on the children with orthostatic disturbances and the patients improving from other diseases, and the following results were obtained: (1) As in the external method with radioisotope, the head of the scintillation detector was easily oriented, and the diversion of orientation was examined by circulation dilution curve, and the cardiac output was easily and safely measured without causing severe pain to the subjects. This method was performed on 40 children in the recumbent position and 27 in orthostatic load, and it was confirmed that the method was fully applicable to the pediatric field. (2) In half of the 20 patients with orthostatic disturbances and 20 control subjects, the cardiac index in the recumbent position was between 3 l/min/m/sup 2/ and 5 l/min/m/sup 2/. Mean cardiac index was 4.45 l/min/m/sup 2/ in male children, while 4.72 l/min/m/sup 2/ in female children. This mean value was the same or a little higher than the reported adult value.

  20. Formic acid hydrolysis/liquid chromatography isotope dilution mass spectrometry: An accurate method for large DNA quantification.

    Science.gov (United States)

    Shibayama, Sachie; Fujii, Shin-Ichiro; Inagaki, Kazumi; Yamazaki, Taichi; Takatsu, Akiko

    2016-10-14

    Liquid chromatography-isotope dilution mass spectrometry (LC-IDMS) with formic acid hydrolysis was established for the accurate quantification of λDNA. The over-decomposition of nucleobases in formic acid hydrolysis was restricted by optimizing the reaction temperature and the reaction time, and accurately corrected by using deoxynucleotides (dNMPs) and isotope-labeled dNMPs as the calibrator and the internal standard, respectively. The present method could quantify λDNA with an expanded uncertainty of 4.6% using 10fmol of λDNA. The analytical results obtained with the present method were validated by comparing with the results of phosphate-base quantification by inductively coupled plasma-mass spectrometry (ICP-MS). The results showed good agreement with each other. We conclude that the formic acid hydrolysis/LC-IDMS method can quantify λDNA accurately and is promising as the primary method for the certification of DNA as reference material. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Method for control of NOx emission from combustors using fuel dilution

    Science.gov (United States)

    Schefer, Robert W [Alamo, CA; Keller, Jay O [Oakland, CA

    2007-01-16

    A method of controlling NOx emission from combustors. The method involves the controlled addition of a diluent such as nitrogen or water vapor, to a base fuel to reduce the flame temperature, thereby reducing NOx production. At the same time, a gas capable of enhancing flame stability and improving low temperature combustion characteristics, such as hydrogen, is added to the fuel mixture. The base fuel can be natural gas for use in industrial and power generation gas turbines and other burners. However, the method described herein is equally applicable to other common fuels such as coal gas, biomass-derived fuels and other common hydrocarbon fuels. The unique combustion characteristics associated with the use of hydrogen, particularly faster flame speed, higher reaction rates, and increased resistance to fluid-mechanical strain, alter the burner combustion characteristics sufficiently to allow operation at the desired lower temperature conditions resulting from diluent addition, without the onset of unstable combustion that can arise at lower combustor operating temperatures.

  2. Quantitative kinetics of renal glucose metabolism by the isotope dilution method in the unanesthetized sheep

    International Nuclear Information System (INIS)

    Sasaki, Shin-ichi; Watanabe, Yasukuni; Ambo, Kaichi; Tsuda, Tsuneyuki.

    1982-01-01

    Renal glucose production and utilization rates in normal fed and fasted sheep were determined by the measurements of renal blood flow and arteriovenous 14 C-glucose and glucose concentration differences using the method of primed continuous infusion of u- 14 C-glucose. At the same time total body glucose turnover rate was measured, and the contribution of renal glucose production to glucose requirement in the whole animal was quantitatively estimated. The renal blood flow for fed and fasted sheep were 20 +- 1 and 20 +- 3 ml/min/kg, respectively. No significant difference in the renal blood flow existed between the groups. The total body glucose turnover rate in fasted sheep (1.68 +- 0.20 mg/min/kg) was significantly lowered (P < 0.01) than that of fed sheep (2.20 +- 0.13 mg/min/kg). The renal glucose production rate in fed sheep was 0.47 +- 0.05 mg/min/kg and this rate accounted for about 21.4% of the glucose turnover rate. The renal glucose production rate in fasted sheep decreased to about 45% of that in fed sheep. However, the renal glucose utilization rate was similar in fed (0.26 +- 0.04 mg/min/kg) and fasted sheep (0.27 +- 0.04 mg/min/kg). Net renal glucose production rate in fed sheep, which was measured by the method of arteriovenous glucose concentration differences, was 0.22 +- 0.05 mg/min/kg, but that in fasted sheep was a negative value. These results suggest that the kidney of ruminant seems to produce a significant amount of glucose and to utilize it simultaneously with production. (author)

  3. A new method for the determination of NO2 traces using isotope dilution and mass spectrometry analysis

    International Nuclear Information System (INIS)

    Stevens, C.; Barat, F.; Nguyen Nghi, H.

    1975-01-01

    A new method for the determination of NO 2 traces, in the order of 1ppb (10 -9 ), in atmosphere and stratosphere is described. The method consists in an isotope dilution technique using 15 NO 2 , followed by the reduction of NO 2 to N 2 and a mass spectrometry analysis. A known amount of 15 NO 2 is added to the air samples. Then, NO 2 is separated from H 2 O, HNO 3 , CO 2 and N 2 O and transferred to a SiO 2 reactor by trapping at -196 deg C. In the reactor NO 2 is reduced to N 2 by reaction with electrolytic Cu heated at 580 deg C. The mass 29/mass 30 ratio corresponding to 15 N 14 N and 15 N 15 N is determined by mass spectrometry. The sensitivity of the method depends on the contamination introduced during the analysis of the sample (reagents, separation and measuring devices). The contamination is reproducible and in the order of 4.5+-0.5 10 -2 mm 3 N 2 [fr

  4. Application of isotope dilution method for measuring bioavailability of organic contaminants sorbed to dissolved organic matter (DOM)

    Energy Technology Data Exchange (ETDEWEB)

    Delgado-Moreno, Laura, E-mail: laura.delgado@eez.csic.es; Wu, Laosheng; Gan, Jay

    2015-08-15

    Natural waters such as surface water and sediment porewater invariably contain dissolved organic matter (DOM). Association of strongly hydrophobic contaminants (HOCs) with DOM leads to decreased toxicity and bioavailability, but bioavailability of DOM-sorbed HOCs is difficult to measure. Current methods to estimate bioavailability of HOCs in water are based on only the freely dissolved concentration (C{sub free}). The ignorance of the exchangeable fraction of HOCs sorbed on DOM may result in an underestimation of the toxicity potential of HOCs to aquatic organisms. Here we explore the applicability of an isotope dilution method (IDM) to measuring the desorption fraction of DOM-sorbed pyrene and bifenthrin and determining their exchangeable pool (E) as an approximation of bioavailability. E values, expressed as percentage of the total concentration, ranged between 0.80 and 0.92% for pyrene and 0.74 and 0.85% for bifenthrin, depending primarily on the amount of chemical in the freely dissolved form. However, between 34 and 78% of the DOM-sorbed pyrene was exchangeable. This fraction ranged between 23% and 82% for bifenthrin. The ability of IDM to predict bioavailability was further shown from a significant relationship (r{sup 2} > 0.72, P < 0.0001) between E and bioaccumulation into Daphnia magna. Therefore, IDM may be used to improve the bioavailability measurement and risk assessment of HOCs in aquatic systems.

  5. Application of isotope dilution method for measuring bioavailability of organic contaminants sorbed to dissolved organic matter (DOM)

    International Nuclear Information System (INIS)

    Delgado-Moreno, Laura; Wu, Laosheng; Gan, Jay

    2015-01-01

    Natural waters such as surface water and sediment porewater invariably contain dissolved organic matter (DOM). Association of strongly hydrophobic contaminants (HOCs) with DOM leads to decreased toxicity and bioavailability, but bioavailability of DOM-sorbed HOCs is difficult to measure. Current methods to estimate bioavailability of HOCs in water are based on only the freely dissolved concentration (C free ). The ignorance of the exchangeable fraction of HOCs sorbed on DOM may result in an underestimation of the toxicity potential of HOCs to aquatic organisms. Here we explore the applicability of an isotope dilution method (IDM) to measuring the desorption fraction of DOM-sorbed pyrene and bifenthrin and determining their exchangeable pool (E) as an approximation of bioavailability. E values, expressed as percentage of the total concentration, ranged between 0.80 and 0.92% for pyrene and 0.74 and 0.85% for bifenthrin, depending primarily on the amount of chemical in the freely dissolved form. However, between 34 and 78% of the DOM-sorbed pyrene was exchangeable. This fraction ranged between 23% and 82% for bifenthrin. The ability of IDM to predict bioavailability was further shown from a significant relationship (r 2 > 0.72, P < 0.0001) between E and bioaccumulation into Daphnia magna. Therefore, IDM may be used to improve the bioavailability measurement and risk assessment of HOCs in aquatic systems

  6. System modeling and identification in indicator dilution method for assessment of ejection fraction and pulmonary blood volume

    NARCIS (Netherlands)

    Bharath, H.N.; Prabhu, K.M.M.; Korsten, H.H.M.; Mischi, M.

    2012-01-01

    Clinically relevant cardiovascular parameters, such as pulmonary blood volume (PBV) and ejection fraction (EF), can be assessed through indicator dilution techniques. Among these techniques, which are typically invasive due to the need for central catheterization, contrast ultrasonography provides a

  7. The effect of different levels of fertilizer on nitrogen nutrient of pasture using 15N-isotope dilution method

    International Nuclear Information System (INIS)

    Wei Dongpu; Bai Lingyu; Hua Luo; Yao Yunyin

    2000-01-01

    A pot experiment was carried out to study the effect of different levels of fertilizer on N% of ryegrass in monoculture or mixed culture with white clover and symbiotic dinitrogen fixation of white clover by using 15 N-isotope dilution method. It showed that (1) N% of ryegrass in monoculture or mixed culture was the highest at 67 days after fertilizing (DAF) and decreased with time; (2) N% of white clover was the greatest at 67 DAF, slightly decreased at 92 DAF, and then increased at 137 DAF, related to the increasing of nitrogen fixation by white clover; (3) At 164 kg 15 NH 4 SO 4 /hm 2 , N% of ryegrass in mixed culture at different cutting time was greater than that in monoculture. It obviously occurred that fixed nitrogen was transferred from white clover to ryegrass in mixed; (4) During the whole growth period, the main nitrogen resource of white clover was symbiotic dinitrogen fixation and that of ryegrass was soil nitrogen; (5) Effect of different levels of applied N on N% of ryegrass and white clover was significant

  8. The isotope-dilution method of fluorine microestimation; Microdosage du fluor pur dilution isotopique; Mikroopredelenie ftora no metodu razbavleniya izotopov; Microvaloracion del fluor por dilucion isotopica

    Energy Technology Data Exchange (ETDEWEB)

    Kudahl, J N; Fremlin, J H; Hardwick, J L [Department of Physics, University of Birmingham (United Kingdom)

    1962-01-15

    Fluoride ions are adsorbed on glass from acid solution and, for solutions containing less than 100 ppm of fluorine, the amount adsorbed varies very regularly with concentration. A certain volume of a carrier-free solution of the unstable isotope F{sup 18} is added to each of a set of acid fluoride solutions which may be a few milligrams, or less, in size. If the solutions are applied to a defined area of glass, some of the F{sup 18} is adsorbed and this can be fixed by raising the pH when equilibrium has been reached. The radioactivity of the glass is a measure of the total amount of fluoride on the glass and can be used to draw an adsorption isotherm from which the fluorine content of an unknown solution in the set can be found. The effects of pH, and the presence of calcium and phosphate ions have been studied, and it has been shown that organic materials may be ashed safely if calcium or magnesium ions are present. The accuracy of the method is independent of the fluoride concentration down to concentrations of a fraction of a ppm. (author) [French] L'ion de fluorure d'une solution acide est adsorbe sur du verre; pour des solutions contenant moins de 100 ppm de fluor, la quantite adsorbee varie tres regulierement en fonction de la concentration. Un certain volume d'une solution, sans entraineur-, de l'isotope instable {sup 18}F est ajoute a une serie de solutions acides de fluorure; il peut s'agir de quantites de l'ordre de quelques milligrammes, ou meme moins. Si l'on applique les solutions sur une surface bien definie de verre, une partie du {sup 18}F est adsorbee; on peut la fixer en augmentant le pH des que l'equilibre a ete realise. La radioactivite du verre donne la mesure de la quantite totale de fluorure fixe sur le verre; elle peut servir a etablir l'isotherme d'adsorption, dont en peut deduire la teneur en fluor de toute solution de la serie. Les auteurs ont etudie les effets du pH et la presence d'ions de calcium et de magnesium; ils ont montre que

  9. Validity of the tritiated thymidine method for estimating bacterial growth rates: measurement of isotope dilution during DNA synthesis

    International Nuclear Information System (INIS)

    Pollard, P.C.; Moriarty, D.J.W.

    1984-01-01

    The rate of tritiated thymidine incorporation into DNA was used to estimate bacterial growth rates in aquatic environments. To be accurate, the calculation of growth rates has to include a factor for the dilution of isotope before incorporation. The validity of an isotope dilution analysis to determine this factor was verified in experiments reported here with cultures of a marine bacterium growing in a chemostat. Growth rates calculated from data on chemostat dilution rates and cell density agreed well with rates calculated by tritiated thymidine incorporation into DNA and isotope dilution analysis. With sufficiently high concentrations of exogenous thymidine, de novo synthesis of deoxythymidine monophosphate was inhibited, thereby preventing the endogenous dilution of isoope. The thymidine technique was also shown to be useful for measuring growth rates of mixed suspensions of bacteria growing anaerobically. Thymidine was incorporated into the DNA of a range of marine pseudomonads that were investigated. Three species did not take up thymidine. The common marine cyanobacterium Synechococcus species did not incorporate thymidine into DNA

  10. Gadoxetate disodium-induced tachypnoea and the effect of dilution method. A proof-of-concept study in mice

    Energy Technology Data Exchange (ETDEWEB)

    Akai, Hiroyuki; Yasaka, Koichiro; Kunimatsu, Akira [University of Tokyo, Department of Radiology, Institute of Medical Science, Tokyo (Japan); Nojima, Masanori [University of Tokyo, Division of Advanced Medicine Promotion, The Advanced Clinical Research Centre, Institute of Medical Science, Tokyo (Japan); Inoue, Yusuke [Kitasato University School of Medicine, Department of Diagnostic Radiology, Sagamihara, Kanagawa (Japan); Abe, Osamu [University of Tokyo, Department of Radiology, Graduate School of Medicine, Tokyo (Japan); Ohtomo, Kuni [International University of Health and Welfare, Ohtawara, Tochigi (Japan); Kiryu, Shigeru [International University of Health and Welfare Hospital, Department of Radiology, Nasushiobara, Tochigi (Japan)

    2018-02-15

    To directly investigate the rapid respiratory effect of gadoxetate disodium in an experimental study using mice. After confirming the steady respiratory state under general anaesthesia, eight mice were injected with all test agents in the following order: phosphate-buffered saline (A, control group), 1.25 mmol/kg of gadoteridol (B) or gadopentetate dimeglumine (C), or 0.31 mmol/kg of gadoxetate disodium (D, E). The experimenter was not blinded to the agents. The injection dose was fixed as 100 μL for Groups A-D and 50 μL for Group E. We continuously monitored and recorded respiratory rate (RR), peripheral oxygen saturation (SpO{sub 2}), and heart rate. The time-series changes from 0 to 30 s were compared by the linear mixed method Groups D and E showed the largest RR increase (20.6 and 20.3 breaths/min, respectively) and were significantly larger compared to Group A (3.36 breaths/min, both P<0.001). RR change of Groups D and E did not differ. RR change of Groups B and C was smaller (0.72 and 12.4 breaths/min, respectively) and did not differ statistically with Group A. Significant bradycardia was observed only in Group C (P<0.001). SpO{sub 2} was constant in all groups. Gadoxetate disodium causes a rapid tachypnoea without significant change of SpO{sub 2} and heart rate regardless of the dilution method. (orig.)

  11. Moessbauer studies of SnO2 powders doped with dilute 57Fe, prepared by a sol-gel method

    International Nuclear Information System (INIS)

    Nomur, K.; Sakuma, J.; Takeda, M.

    2006-01-01

    Diluted magnetic semiconductor (DMS) is prospected as new materials with both semiconductor and magnetic properties. In order to confirm these phenomena, we prepared the powders of SnO 2 doped with various amount of 57 Fe by a sol-gel method. Various compositions of Sn 1-x 57 Fe x O 2 were obtained by mixing some ratio of Fe 3+ nitrate solution and acetylacetonate Sn 4+ complex in the ethylene glycol and citric acid solution. The solutions were evaporated, ashed at around 200 grad C, and finally annealed at 500 grad C, 600 grad C, and 650 grad C, respectively. These Sn 1-x 57 Fe x O 2 (x=0.005, 0.01, 0.03 and 0.05) were measured by XRD, VSM, and Moessbauer spectrometry. The prepared powder samples were confirmed to be a rutile structure, but iron compounds were not detected by XRD. Moessbauer spectra of Sn 1-x 57 Fe x O 2 prepared at 500 grad C were shown in Fig. 1. A small amount of broad sextets were observed in MS spectra of Sn 1-x 57 Fe x O 2 in addition to paramagnetic components. The relative intensity seems to be strong with the decrease of the amount of doped Fe. Moessbauer spectrum at 10 K shows clearly the magnetic components. The magnetic sextet was observed in MS spectra of samples prepared at 650 grad C, but the magnetic behavior weakened because of antiferromagnetic α-Fe 2 O 3 , produced due to the phase separation at high temperatures. (authors)

  12. Precision of glucose measurements in control sera by isotope dilution/mass spectrometry: proposed definitive method compared with a reference method

    International Nuclear Information System (INIS)

    Pelletier, O.; Arratoon, C.

    1987-01-01

    This improved isotope-dilution gas chromatographic/mass spectrometric (GC/MS) method, in which [ 13 C]glucose is the internal standard, meets the requirements of a Definitive Method. In a first study with five reconstituted lyophilized sera, a nested analysis of variance of GC/MS values indicated considerable among-vial variation. The CV for 32 measurements per serum ranged from 0.5 to 0.9%. However, concentration and uncertainty values (mmol/L per gram of serum) assigned to one serum by the NBS Definitive Method (7.56 +/- 0.28) were practically identical to those obtained with the proposed method (7.57 +/- 0.20). In the second study, we used twice more [ 13 C]glucose diluent to assay four serum pools and two lyophilized sera. The CV ranged from 0.26 to 0.5% for the serum pools and from 0.28 to 0.59% for the lyophilized sera. In comparison, results by the hexokinase/glucose-6-phosphate dehydrogenase reference method agreed within acceptable limits with those by the Definitive Method but tended to be slightly higher (up to 3%) for lyophilized serum samples or slightly lower (up to 2.5%) for serum pools

  13. Determination of thyroid hormones in mouse tissues by isotope-dilution microflow liquid chromatography-mass spectrometry method.

    Science.gov (United States)

    De Angelis, Meri; Giesert, Florian; Finan, Brian; Clemmensen, Christoffer; Müller, Timo D; Vogt-Weisenhorn, Daniela; Tschöp, Matthias H; Schramm, Karl-Werner

    2016-10-15

    Thyroid hormones (THs) play a critical role in the regulation of many biological processes such as growth, metabolism and development both in humans and wildlife. In general, TH levels are measured by immunoassay (IA) methods but the specificity of the antibodies used in these assays limits selectivity. In the last decade, several analytical methods using liquid chromatography-mass spectrometry (LC-MS) and tandem mass spectrometry (LC-MS/MS) have been developed to measure THs. These new techniques proved to be more accurate than the IA analysis and they were widely used for the determination of TH level in different human and animal tissues. A large part of LC-MS/MS methods described in literature employed between 200 and 500mg of sample, however this quantity can be considered too high especially when preclinical studies are conducted using mice as test subjects. Thus an analytical method that reduces the amount of tissue is essential. In this study, we developed a procedure for the analysis of six THs; L-thyroxine (T4), 3,3',5-triiodo-l-thyronine (T3), 3,3',5'-triiodo-l-thyronine (rT3), 3,5-diiodo-l-thyronine (rT2), 3,3'-diiodo-l-thyronine (T2), 3-iodo-l-thyronine (T1) using isotope ((13)C6-T4, (13)C6-T3, (13)C6-rT3, (13)C6-T2) dilution liquid chromatography-mass spectrometry. The major difference with previously described methods lies in the utilization of a nano-UPLC (Ultra Performance Liquid Chromatography) system in micro configuration. This approach leads to a reduction compared to the published methods, of column internal diameter, flow rate, and injected volume. The result of all these improvements is a decrease in the amount of sample necessary for the analysis. The method was tested on six different mouse tissues: liver, heart, kidney, muscle, lung and brown adipose tissue (BAT). The nano-UPLC system was interfaced with a quadrupole time-of-flight mass spectrometer (Q-TOF2-MS) using the positive ion mode electrospray ionization. In our analytical method

  14. Use of Limiting Dilution Method for Isolation of Nucleus Pulposus Mesenchymal Stem/Progenitor Cells and Effects of Plating Density on Biological Characteristics and Plasticity

    Directory of Open Access Journals (Sweden)

    Linghan Lin

    2017-01-01

    Full Text Available Objectives. To evaluate the effects of the limiting dilution method and plating density in rat nucleus pulposus mesenchymal stem/progenitor cells (NPMSCs. Materials and Methods. Nucleus pulposus tissues were isolated from 12-week-old male Sprague-Dawley rats and NPMSCs were isolated using limiting dilution method. Cells were then classified into 3 groups according to plating density. Cell morphologies were observed, and colony-forming units, migration abilities, proliferative capacities, cell cycle percentages, multilineage differentiation capacities, stem cell biomarker expression levels, and immunophenotyping were also examined in each group. Results. Low density group (LD had higher morphological homogeneity, stronger colony-forming ability, higher cell proliferation capacity, and enhanced cell migration ability relative to the other two groups (p<0.05. Moreover, LD had more cells entering S phase, with fewer cells arrested in G0/G1 phase (p<0.05. While all three density groups showed a multilineage differentiation potential, LD showed a higher degree of observed and semiquantified lineage specific staining (p<0.05. Furthermore, LD displayed higher expression levels of stem cell biomarkers (Nanog, Oct4, and Sox2 and showed higher percentages of CD29+, CD44+, and CD90+ cells (p<0.05 following flow cytometry analysis. Conclusions. Limiting dilution method is suggested when isolating NPMSCs as a means of improving cell activity and plasticity.

  15. Application of 1- (3,4-dimenthylphenyl)-dodecanedione-1,2-dioxime (MFDDO) to substoichiometris extraction and determination of nickel(II) by the isotope dilution method

    Energy Technology Data Exchange (ETDEWEB)

    Gorski, Z.; Goraczko, W. [Technical University Poznan, Poznan (Poland). Radio and Photo Chemistry Department

    1997-10-01

    The conditions for use of 1-3,4-dimenthylphenyl-dodecanedione-1,2-dioxime (MFDDO) in toluene solution for substoichiometric extraction of Ni(II) from aqueous phases are described. This procedure allows the determination of 0.006-0.06 g/ml of nickel(II) in human urine and blood`s serum samples by the isotope dilution method using {sup 63}Ni(II) 9 refs., 5 figs.

  16. Bioscreening and expression of a camel anti-CTGF VHH nanobody and its renaturation by a novel dialysis-dilution method.

    Science.gov (United States)

    Xue, Xiulei; Fan, Xiaobo; Qu, Qingrong; Wu, Guoqiu

    2016-12-01

    The variable regions of the camel heavy chain antibody, also known as nanobody is the smallest antibody with antigen-binding efficiency. CTGF is considered important during extracellular matrix deposition which was involved in the pathogenesis of fibrosis related diseases. There are several anti-CTGF-C nanobody drugs under developing in pharmacy. In this study, we described the screening of a novel anti-CTGF-C nanobody from the peripheral blood of immunized camel by phage display. The screened nanobody was further expressed and purified from E. coli cells. A sophisticated dialysis-dilution method was designed for the in vitro refolding of the nanobody. The results showed that the expressed nanobody was consisted of 135 amino acid and mainly expressed as inclusion body in E. coli cells. The dialysis-dilution method was very effective and the recovery rate of the renaturation was more than 80 %. The ELISA result suggested the nanobody had been well refolded showing a superior CTGF binding activity to the commercial mouse anti-CTGF-C mAb. In conclusion, the anti-CTGF-C nonobody had been successfully screened by phage display. The dialysis-dilution refolding method was very effective and the recovery rate reached over 80 %.

  17. Application of a General Computer Algorithm Based on the Group-Additivity Method for the Calculation of Two Molecular Descriptors at Both Ends of Dilution: Liquid Viscosity and Activity Coefficient in Water at Infinite Dilution

    Directory of Open Access Journals (Sweden)

    Rudolf Naef

    2017-12-01

    Full Text Available The application of a commonly used computer algorithm based on the group-additivity method for the calculation of the liquid viscosity coefficient at 293.15 K and the activity coefficient at infinite dilution in water at 298.15 K of organic molecules is presented. The method is based on the complete breakdown of the molecules into their constituting atoms, further subdividing them by their immediate neighborhood. A fast Gauss–Seidel fitting method using experimental data from literature is applied for the calculation of the atom groups’ contributions. Plausibility tests have been carried out on each of the calculations using a ten-fold cross-validation procedure which confirms the excellent predictive quality of the method. The goodness of fit (Q2 and the standard deviation (σ of the cross-validation calculations for the viscosity coefficient, expressed as log(η, was 0.9728 and 0.11, respectively, for 413 test molecules, and for the activity coefficient log(γ∞ the corresponding values were 0.9736 and 0.31, respectively, for 621 test compounds. The present approach has proven its versatility in that it enabled the simultaneous evaluation of the liquid viscosity of normal organic compounds as well as of ionic liquids.

  18. High-precision quadruple isotope dilution method for simultaneous determination of nitrite and nitrate in seawater by GCMS after derivatization with triethyloxonium tetrafluoroborate

    Energy Technology Data Exchange (ETDEWEB)

    Pagliano, Enea, E-mail: enea.pagliano@nrc-cnrc.gc.ca; Meija, Juris; Mester, Zoltán

    2014-05-01

    Highlights: • High-precision determination of nitrite and nitrate in seawater. • Use of quadruple isotope dilution. • Aqueous Et₃O⁺BF₄]⁻ derivatization chemistry for GCMS analysis of nitrite and nitrate. Abstract: Quadruple isotope dilution mass spectrometry (ID⁴MS) has been applied for simultaneous determination of nitrite and nitrate in seawater. ID⁴MS allows high-precision measurements and entails the use of isotopic internal standards (¹⁸O-nitrite and ¹⁵N-nitrate). We include a tutorial on ID⁴MS outlining optimal experimental design which generates results with low uncertainties and obviates the need for direct (separate) evaluation of the procedural blank. Nitrite and nitrate detection was achieved using a headspace GCMS procedure based on single-step aqueous derivatization with triethyloxonium tetrafluoroborate at room temperature. In this paper the sample preparation was revised and fundamental aspects of this chemistry are presented. The proposed method has detection limits in the low parts-per-billion for both analytes, is reliable, precise, and has been validated using a seawater certified reference material (MOOS-2). Simplicity of the experimental design, low detection limits, and the use of quadruple isotope dilution makes the present method superior to the state-of-the-art for determination of nitrite and nitrate, and an ideal candidate for reference measurements of these analytes in seawater.

  19. [Evaluation of in vitro antimicrobial activity of cefazolin alone and in combination with cefmetazole or flomoxef using agar dilution method and disk diffusion method].

    Science.gov (United States)

    Matsuo, K; Uete, T

    1992-10-01

    Antimicrobial activities of cefazolin (CEZ) against 251 strains of various clinical isolates obtained during 1989 and 1990 were determined using the Mueller-Hinton agar dilution method at an inoculum level 10(6) CFU/ml. The reliability of the disk susceptility test was also studied using Mueller-Hinton agar and various disks at inoculum levels of 10(3-4) CFU/cm2 in estimating approximate values of MICs. In addition, antimicrobial activities of CEZ and cefmetazole (CMZ) or flomoxef (FMOX) in combination were investigated against methicillin-sensitive and -resistant Staphylococcus aureus (MSSA and MRSA) using the checkerboard agar dilution MIC method and the disk diffusion test either with the disks contained CEZ, CMZ, and FMOX alone, or CEZ, and CMZ or FMOX in combination. In this study, the MICs of CEZ against S. aureus were distributed with the 3 peak values at 0.39 microgram/ml, 3.13 micrograms/ml and > 100 micrograms/ml. MICs against MSSA were 0.39 microgram/ml to 0.78 microgram/ml, whereas those against MRSA were greater than 0.78 microgram/ml. MICs against majority of strains of Enterococcus faecalis were 25 micrograms/ml. Over 90% of strains of Escherichia coli and Klebsiella pneumoniae were inhibited at the level of 3.13 micrograms/ml. About 60% of isolates of indole negative Proteus spp. were inhibited at the levels of less than 3.13 micrograms/ml and 100% at 6.25 micrograms/ml, but MICs against indole positive Proteus spp., Serratia spp. and Pseudomonas aeruginosa were over 100 micrograms/ml. The antimicrobial activities of CEZ against these clinical isolates were not significantly different compared to those reported about 15-20 years ago, except for S. aureus. Highly resistant strains of S. aureus to CEZ were more prevalent in this study. The inhibitory zones obtained with the disk test were compared with MICs. The results of CEZ disk susceptibility test with 30 micrograms disk (Showa) or 10 micrograms disk (prepared in this laboratory) were well

  20. Determination of biomass of mango (Mangifera indica L.) trees by non-destructive method using principle of isotope dilution

    International Nuclear Information System (INIS)

    Kotur, S.C.; Keshava Murthy, S.V.

    2003-01-01

    Biomass of 4-year old trees alphonso mango was estimated by injecting of carrier-free 32 P into the trunk followed by radio-assay of the isotope after a complete dilution of 32 P in the tree, being 3 months after injection. The isotopically calculated plant volume (59 903-68 981 cc plant -1 ) and biomass (31.70 - 36.23 kg plant -1 ) showed good agreement but generally overestimated both by about 23% compared to the actual values determined physically (43 720-60 693 cc plant -1 and 22.88-34.78 kg plant -1 , respectively). Application of the technique in a set of another four 15-year old mango trees yielded volume estimates of 1, 70, 749-1 75 835 cc plant -1 (mean=1, 75 835±1.12%) and biomass estimates of 73.0 - 87.4 kg plant -1 (mean=80.45±6.8%). The technique is of promise in fertilizer use efficiency and nutrient dynamics studies in tree crops. (author)

  1. Optimization of single plate-serial dilution spotting (SP-SDS) with sample anchoring as an assured method for bacterial and yeast cfu enumeration and single colony isolation from diverse samples.

    Science.gov (United States)

    Thomas, Pious; Sekhar, Aparna C; Upreti, Reshmi; Mujawar, Mohammad M; Pasha, Sadiq S

    2015-12-01

    We propose a simple technique for bacterial and yeast cfu estimations from diverse samples with no prior idea of viable counts, designated as single plate-serial dilution spotting (SP-SDS) with the prime recommendation of sample anchoring (10 0 stocks). For pure cultures, serial dilutions were prepared from 0.1 OD (10 0 ) stock and 20 μl aliquots of six dilutions (10 1 -10 6 ) were applied as 10-15 micro-drops in six sectors over agar-gelled medium in 9-cm plates. For liquid samples 10 0 -10 5 dilutions, and for colloidal suspensions and solid samples (10% w/v), 10 1 -10 6 dilutions were used. Following incubation, at least one dilution level yielded 6-60 cfu per sector comparable to the standard method involving 100 μl samples. Tested on diverse bacteria, composite samples and Saccharomyces cerevisiae , SP-SDS offered wider applicability over alternative methods like drop-plating and track-dilution for cfu estimation, single colony isolation and culture purity testing, particularly suiting low resource settings.

  2. Evaluation of electrical broad bandwidth impedance spectroscopy as a tool for body composition measurement in cows in comparison with body measurements and the deuterium oxide dilution method.

    Science.gov (United States)

    Schäff, C T; Pliquett, U; Tuchscherer, A; Pfuhl, R; Görs, S; Metges, C C; Hammon, H M; Kröger-Koch, C

    2017-05-01

    Body fatness and degree of body fat mobilization in cows vary enormously during their reproduction cycle and influence energy partitioning and metabolic adaptation. The objective of the study was to test bioelectrical impedance spectroscopy (BIS) as a method for predicting fat depot mass (FDM), in living cows. The FDM is defined as the sum of subcutaneous, omental, mesenteric, retroperitoneal, and carcass fat mass. Bioelectrical impedance spectroscopy is compared with the prediction of FDM from the deuterium oxide (DO) dilution method and from body conformation measurements. Charolais × Holstein Friesian (HF; = 18; 30 d in milk) crossbred cows and 2 HF (lactating and nonlactating) cows were assessed by body conformation measurements, BIS, and the DO dilution method. The BCS of cows was a mean of 3.68 (SE 0.64). For the DO dilution method, a bolus of 0.23 g/kg BW DO (60 atom%) was intravenously injected and deuterium (D) enrichment was analyzed in plasma and whey by stabile isotope mass spectrometry, and total body water content was calculated. Impedance measurement was performed using a 4-electrode interface and time domain-based measurement system consisting of a voltage/current converter for applying current stimulus and an amplifier for monitoring voltage across the sensor electrodes. For the BIS, we used complex impedances over three frequency decades that delivers information on intra- and extracellular water and capacity of cell membranes. Impedance data (resistance of extra- and intracellular space, cell membrane capacity, and phase angle) were extracted 1) by simple curve fit to extract the resistance at direct current and high frequency and 2) by using an electrical equivalent circuit. Cows were slaughtered 7 d after BIS and D enrichment measurements and dissected for the measurement of FDM. Multiple linear regression analyses were performed to predict FDM based on data obtained from body conformation measurements, BIS, and D enrichment, and applied

  3. Antimicrobial Activity of Ephedra pachyclada Methanol Extract on Some Enteric Gram Negative Bacteria Which Causes Nosocomial Infections by Agar Dilution Method

    Directory of Open Access Journals (Sweden)

    Amin Sadeghi Dosari

    2016-10-01

    Full Text Available Background Past history indicates that plants were served as an important source of medicine. Otherwise, in developing countries people use medicinal plants against infectious disease because they cannot afford expensive drugs. Due to increasing rate of drug-resistant diseases, there is an urgent need to detect novel antimicrobial compounds from medicinal plants. Objectives The aim of the present study was to determine Antimicrobial activity of Ephedra pachyclada methanol extract on some enteric Gram-negative bacteria which causes nosocomial infections by agar dilution method. Methods In this cross-sectional study, in order to examine the antimicrobial effects of Ephedra pachyclada extract on intestinal Gram-negative bacteria, we exposed them to 0/128, 0/25, 0/5, 1, 2, 4 and 8 mg/mL of the extract. Ephedra pachyclada was collected from Jiroft Heights and methanolic extract was prepared with maceration method, during which, 50 gr powder of Ephedra pachyclada was dissolved in 300 mL of 80% methanol. Results In this study, the antibacterial effects of Ephedra pachyclada extract on Gram-negative bacteria such as Pseudomonas aeruginosa, Escherichia coli (PTCC-O157, Escherichia coli (ATCC-25922, Klebsiella pnemoniae, Serratia marcescens was investigated, defining the minimum inhibitory concentration (MIC by agar dilution method. It has been demonstrated that methanolic extract of Ephedra pachyclada affect intestinal Gram-negative bacteria. Conclusions The result showed that, Ephedra pachyclada extract has effective antimicrobial ingredients which are cheap and readily available. It can be used for medicinal purposes in the production of antimicrobial drug.

  4. On the use of the serial dilution culture method to enumerate viable phytoplankton in natural communities of plankton subjected to ballast water treatment.

    Science.gov (United States)

    Cullen, John J; MacIntyre, Hugh L

    2016-01-01

    Discharge standards for ballast water treatment (BWT) systems are based on concentrations of living cells, for example, as determined with vital stains. Ultraviolet radiation (UV) stops the reproduction of microorganisms without killing them outright; they are living, but not viable, and ecologically as good as dead. Consequently, UV-treated discharge can be compliant with the intent of regulation while failing a live/dead test. An alternative evaluation of BWT can be proposed based on the assessment of viable, rather than living, cells in discharge water. In principle, the serial dilution culture-most probable number (SDC-MPN) method provides the appropriate measure for phytoplankton. But, the method has been criticized, particularly because it is thought that many phytoplankton species cannot be cultured. A review of the literature shows that although SDC-MPN has been used for more than 50 years-generally to identify and count phytoplankton species that cannot be preserved-its application to enumerate total viable phytoplankton seems to be new, putting past criticisms of the method in a different light. Importantly, viable cells need to grow only enough to be detected, not to be brought into sustained culture, and competition between species in a dilution tube is irrelevant as long as the winner is detectable. Thorough consideration of sources of error leads to recommendations for minimizing and quantifying uncertainties by optimizing growth conditions and conducting systematic comparisons. We conclude that with careful evaluation, SDC-MPN is potentially an effective method for assessing the viability of phytoplankton after BWT.

  5. The preparation of nucleotides uniformly labelled with carbon-14 by biosynthetic methods. Isolation of adenylic, uridylic, cytidylic,and guanylic acids, from the alkaline hydrolysate of escherichia coli RNA; Preparacion de nucleiotidos uniformemente marcados con 14{sup C}, por via biosintetica. Aislamiento de los acidos adenilico, uridilico, citidilico y guanilico, procedentes de la hidrolisis alcalina de RNA de escherichia Coli.

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Pineda, M D; Pacheco Lopez, J

    1978-07-01

    A method is described for the preparation and analysis of adenylic, uri dilic, cytidi- 11c and guanylic acids, labelled with 14{sup C}. Escherichia coli cells have been labelled by growing them in a medi dia containing glucose-14{sup C} as their only source of carbon. RNA is isolated from the cells, and after hydrolysis of the molecule the resulting nucleotides are separated by gel filtration and exchange chromatography. Chemical and radiochemical purity of the Isolated nucleotides is determined, and also its specific radioactivity. (Author) 30 refs.

  6. Cost effectiveness of dilute chemical decontamination

    International Nuclear Information System (INIS)

    LeSurf, J.E.; Weyman, G.D.

    The basic principles of dilute chemical decontamination are described, as well as the method of application. Methods of computing savings in radiation dose and costs are presented, with results from actual experience and illustrative examples. It is concluded that dilute chemical decontamination is beneficial in many cases. It reduces radiation exposure of workers, saves money, and simplifies maintenance work

  7. Isotopic dilution methods to determine the gross transformation rates of nitrogen, phosphorus, and sulfur in soil: a review of the theory, methodologies, and limitations

    International Nuclear Information System (INIS)

    Di, H. J.; Cameron, K. C.; McLaren, R. G.

    2000-01-01

    The rates at which nutrients are released to, and removed from, the mineral nutrient pool are important in regulating the nutrient supply to plants. These nutrient transformation rates need to be taken into account when developing nutrient management strategies for economical and sustainable production. A method that is gaining popularity for determining the gross transformation rates of nutrients in the soil is the isotopic dilution technique. The technique involves labelling a soil mineral nutrient pool, e.g. NH 4 + , NO 3 - , PO 4 3- , or SO 4 2- , and monitoring the changes with time of the size of the labelled nutrient pool and the excess tracer abundance (atom %, if stable isotope tracer is used) or specific activity (if radioisotope is used) in the nutrient pool. Because of the complexity of the concepts and procedures involved, the method has sometimes been used incorrectly, and results misinterpreted. This paper discusses the isotopic dilution technique, including the theoretical background, the methodologies to determine the gross flux rates of nitrogen, phosphorus, and sulfur, and the limitations of the technique. The assumptions, conceptual models, experimental procedures, and compounding factors are discussed. Possible effects on the results by factors such as the uniformity of tracer distribution in the soil, changes in soil moisture content, substrate concentration, and aeration status, and duration of the experiment are also discussed. The influx and out-flux transformation rates derived from this technique are often contributed by several processes simultaneously, and thus cannot always be attributed to a particular nutrient transformation process. Despite the various constraints or possible compounding factors, the technique is a valuable tool that can provide important quantitative information on nutrient dynamics in the soil-plant system. Copyright (2000) CSIRO Publishing

  8. Prediction of fat-free mass by bioelectrical impedance analysis in older adults from developing countries: a cross-validation study using the deuterium dilution method

    International Nuclear Information System (INIS)

    Mateo, H. Aleman; Romero, J. Esparza; Valencia, M.E.

    2010-01-01

    Objective: Several limitations of published bioelectrical impedance analysis (BIA) equations have been reported. The aims were to develop in a multiethnic, elderly population a new prediction equation and cross- validate it along with some published BIA equations for estimating fat-free mass using deuterium oxide dilution as the reference method. Design and setting: Cross-sectional study of elderly from five developing countries. Methods: Total body water (TBW) measured by deuterium dilution was used to determine fat-free mass (FFM) in 383 subjects. Anthropometric and BIA variables were also measured. Only 377 subjects were included for the analysis, randomly divided into development and cross-validation groups after stratified by gender. Stepwise model selection was used to generate the model and Bland Altman analysis was used to test agreement. Results: FFM = 2.95 - 3.89 (Gender) + 0.514 (Ht2/Z) + 0.090 (Waist) + 0.156 (Body weight). The model fit parameters were an R2, total F-Ratio, and the SEE of 0.88, 314.3, and 3.3, respectively. None of the published BIA equations met the criteria for agreement. The new BIA equation underestimated FFM by just 0.3 kg in the cross-validation sample. The mean of the difference between FFM by TBW and the new BIA equation were not significantly different; 95% of the differences were between the limits of agreement of -6.3 to 6.9 kg of FFM. There was no significant association between the mean of the differences and their averages (r= 0.008 and p= 0.2). Conclusions:This new BIA equation offers a valid option compared with some of the current published BIA equations to estimate FFM in elderly subjects from five developing countries. (Authors)

  9. A semi-Lagrangian transport method for kinetic problems with application to dense-to-dilute polydisperse reacting spray flows

    Energy Technology Data Exchange (ETDEWEB)

    Doisneau, François, E-mail: fdoisne@sandia.gov; Arienti, Marco, E-mail: marient@sandia.gov; Oefelein, Joseph C., E-mail: oefelei@sandia.gov

    2017-01-15

    For sprays, as described by a kinetic disperse phase model strongly coupled to the Navier–Stokes equations, the resolution strategy is constrained by accuracy objectives, robustness needs, and the computing architecture. In order to leverage the good properties of the Eulerian formalism, we introduce a deterministic particle-based numerical method to solve transport in physical space, which is simple to adapt to the many types of closures and moment systems. The method is inspired by the semi-Lagrangian schemes, developed for Gas Dynamics. We show how semi-Lagrangian formulations are relevant for a disperse phase far from equilibrium and where the particle–particle coupling barely influences the transport; i.e., when particle pressure is negligible. The particle behavior is indeed close to free streaming. The new method uses the assumption of parcel transport and avoids to compute fluxes and their limiters, which makes it robust. It is a deterministic resolution method so that it does not require efforts on statistical convergence, noise control, or post-processing. All couplings are done among data under the form of Eulerian fields, which allows one to use efficient algorithms and to anticipate the computational load. This makes the method both accurate and efficient in the context of parallel computing. After a complete verification of the new transport method on various academic test cases, we demonstrate the overall strategy's ability to solve a strongly-coupled liquid jet with fine spatial resolution and we apply it to the case of high-fidelity Large Eddy Simulation of a dense spray flow. A fuel spray is simulated after atomization at Diesel engine combustion chamber conditions. The large, parallel, strongly coupled computation proves the efficiency of the method for dense, polydisperse, reacting spray flows.

  10. A robust two-node, 13 moment quadrature method of moments for dilute particle flows including wall bouncing

    Science.gov (United States)

    Sun, Dan; Garmory, Andrew; Page, Gary J.

    2017-02-01

    For flows where the particle number density is low and the Stokes number is relatively high, as found when sand or ice is ingested into aircraft gas turbine engines, streams of particles can cross each other's path or bounce from a solid surface without being influenced by inter-particle collisions. The aim of this work is to develop an Eulerian method to simulate these types of flow. To this end, a two-node quadrature-based moment method using 13 moments is proposed. In the proposed algorithm thirteen moments of particle velocity, including cross-moments of second order, are used to determine the weights and abscissas of the two nodes and to set up the association between the velocity components in each node. Previous Quadrature Method of Moments (QMOM) algorithms either use more than two nodes, leading to increased computational expense, or are shown here to give incorrect results under some circumstances. This method gives the computational efficiency advantages of only needing two particle phase velocity fields whilst ensuring that a correct combination of weights and abscissas is returned for any arbitrary combination of particle trajectories without the need for any further assumptions. Particle crossing and wall bouncing with arbitrary combinations of angles are demonstrated using the method in a two-dimensional scheme. The ability of the scheme to include the presence of drag from a carrier phase is also demonstrated, as is bouncing off surfaces with inelastic collisions. The method is also applied to the Taylor-Green vortex flow test case and is found to give results superior to the existing two-node QMOM method and is in good agreement with results from Lagrangian modelling of this case.

  11. Use of Fourier transformed infrared spectrophotometer (FTIR) for determination of breastmilk output by the deuterium dilution method among Senegalese women

    International Nuclear Information System (INIS)

    Sarr Cisse, Aita; Diaham, Babou; Dossou, Nicole; Guiro, Amadou Tidiane; Wade, Salimata; Bluck, Leslie

    2002-01-01

    Breastmilk output can be estimated from the mother's total body water and water turnover rates after oral administration of deuterium oxide. Usually the deuterium enrichments are determined using a isotope ratio mass spectrometer, which is expensive and requires a specialist for operation and maintenance. Such equipment is dfficult to set up in developing countries. A less expensive method was developed which uses a Fourier transform infrared spectrophotometer (FTIR) for deuterium enrichment analysis. This study evaluated the constraints of using FTIR to study lactating women in Senegal. The deuterium isotope method was found to be adequate for free living subjects and presented few constraints except for the duration of the saliva sampling (14 days). The method offers the opportunity to determine simultaneously breastmilk output, mother's body composition, and breastfeeding practices. Deuterium sample enrichments measured with FTIR were fast and easy, but for spectrum quality some environmental control is required to optimize the results. (Authors)

  12. Determination of thyroid hormones in mouse tissues by isotope-dilution microflow liquid chromatography-mass spectrometry method

    DEFF Research Database (Denmark)

    De Angelis, Meri; Giesert, Florian; Finan, Brian

    2016-01-01

    ). The nano-UPLC system was interfaced with a quadrupole time-of-flight mass spectrometer (Q-TOF2-MS) using the positive ion mode electrospray ionization. In our analytical method the instrumental calibration curves were constructed from 0 to 100pgμL(-1) and all of them showed good linearity (r(2)>0.99...

  13. Method and apparatus for detecting dilute concentrations of radioactive xenon in samples of xenon extracted from the atmosphere

    Science.gov (United States)

    Warburton, William K.; Hennig, Wolfgang G.

    2018-01-02

    A method and apparatus for measuring the concentrations of radioxenon isotopes in a gaseous sample wherein the sample cell is surrounded by N sub-detectors that are sensitive to both electrons and to photons from radioxenon decays. Signal processing electronics are provided that can detect events within the sub-detectors, measure their energies, determine whether they arise from electrons or photons, and detect coincidences between events within the same or different sub-detectors. The energies of detected two or three event coincidences are recorded as points in associated two or three-dimensional histograms. Counts within regions of interest in the histograms are then used to compute estimates of the radioxenon isotope concentrations. The method achieves lower backgrounds and lower minimum detectable concentrations by using smaller detector crystals, eliminating interference between double and triple coincidence decay branches, and segregating double coincidences within the same sub-detector from those occurring between different sub-detectors.

  14. Isotope dilution liquid chromatography - mass spectrometry methods for fat- and water-soluble vitamins in nutritional formulations.

    Science.gov (United States)

    Phinney, Karen W; Rimmer, Catherine A; Thomas, Jeanice Brown; Sander, Lane C; Sharpless, Katherine E; Wise, Stephen A

    2011-01-01

    Vitamins are essential to human health, and dietary supplements containing vitamins are widely used by individuals hoping to ensure they have adequate intake of these important nutrients. Measurement of vitamins in nutritional formulations is necessary to monitor regulatory compliance and in studies examining the nutrient intake of specific populations. Liquid chromatographic methods, primarily with UV absorbance detection, are well established for both fat- and water-soluble measurements, but they do have limitations for certain analytes and may suffer from a lack of specificity in complex matrices. Liquid chromatography-mass spectrometry (LC-MS) provides both sensitivity and specificity for the determination of vitamins in these matrices, and simultaneous analysis of multiple vitamins in a single analysis is often possible. In this work, LC-MS methods were developed for both fat- and water-soluble vitamins and applied to the measurement of these analytes in two NIST Standard Reference Materials. When possible, stable isotope labeled internal standards were employed for quantification.

  15. Contribution to diagnostics/prognostics of tuberculosis in children. I. New methods of assaying zinc and simultaneously copper and zinc in diluted sera by flame atomic-absorption spectrometry

    Directory of Open Access Journals (Sweden)

    Luterotti Svjetlana

    2015-09-01

    Full Text Available In an attempt to provide a reliable status of metal ions in children, new methods of analysis of children’s sera are proposed. New flame atomic-absorption spectrometric (FAAS methods are simple, cost- and time-effective and, above all, labor-, reagent- and sample-saving. Two methods were suggested: method A for simultaneous determination of Cu and Zn from 5-fold diluted sera, and method B, for assaying zinc alone in 10-fold diluted samples. Both methods are based on a single-step sample pretreatment (deproteinization with 3 mol dm–3 HCl. Method A uses a single-step calibration with a mixed standard. The main advantage of method B is an additional reduction in sample consumption. Both methods were fully validated against reference methods. Accuracy, sensitivity and precision have proven them to be comparable to the reference methods in terms of analytical performance, and applicable to analyses of children’s sera.

  16. Quality-assurance procedures: Method 5G determination of particulate emissions from wood heaters from a dilution tunnel sampling location

    Energy Technology Data Exchange (ETDEWEB)

    Ward, T.E.; Hartman, M.W.; Olin, R.C.; Rives, G.D.

    1989-06-01

    Quality-assurance procedures are contained in this comprehensive document intended to be used as an aid for wood-heater manufacturers and testing laboratories in performing particulate matter sampling of wood heaters according to EPA protocol, Method 5G. These procedures may be used in research and development, and as an aid in auditing and certification testing. A detailed, step-by-step quality assurance guide is provided to aid in the procurement and assembly of testing apparatus, to clearly describe the procedures, and to facilitate data collection and reporting. Suggested data sheets are supplied that can be used as an aid for both recordkeeping and certification applications. Throughout the document, activity matrices are provided to serve as a summary reference. Checklists are also supplied that can be used by testing personnel. Finally, for the purposes of ensuring data quality, procedures are outlined for apparatus operation, maintenance, and traceability. These procedures combined with the detailed description of the sampling and analysis protocol will help ensure the accuracy and reliability of Method 5G emission-testing results.

  17. An isotope dilution ultra high performance liquid chromatography-tandem mass spectrometry method for the simultaneous determination of sugars and humectants in tobacco products.

    Science.gov (United States)

    Wang, Liqun; Cardenas, Roberto Bravo; Watson, Clifford

    2017-09-08

    CDC's Division of Laboratory Sciences developed and validated a new method for the simultaneous detection and measurement of 11 sugars, alditols and humectants in tobacco products. The method uses isotope dilution ultra high performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) and has demonstrated high sensitivity, selectivity, throughput and accuracy, with recoveries ranging from 90% to 113%, limits of detection ranging from 0.0002 to 0.0045μg/mL and coefficients of variation (CV%) ranging from 1.4 to 14%. Calibration curves for all analytes were linear with linearity R 2 values greater than 0.995. Quantification of tobacco components is necessary to characterize tobacco product components and their potential effects on consumer appeal, smoke chemistry and toxicology, and to potentially help distinguish tobacco product categories. The researchers analyzed a variety of tobacco products (e.g., cigarettes, little cigars, cigarillos) using the new method and documented differences in the abundance of selected analytes among product categories. Specifically, differences were detected in levels of selected sugars found in little cigars and cigarettes, which could help address appeal potential and have utility when product category is unknown, unclear, or miscategorized. Copyright © 2017. Published by Elsevier B.V.

  18. Introducing AAA-MS, a rapid and sensitive method for amino acid analysis using isotope dilution and high-resolution mass spectrometry.

    Science.gov (United States)

    Louwagie, Mathilde; Kieffer-Jaquinod, Sylvie; Dupierris, Véronique; Couté, Yohann; Bruley, Christophe; Garin, Jérôme; Dupuis, Alain; Jaquinod, Michel; Brun, Virginie

    2012-07-06

    Accurate quantification of pure peptides and proteins is essential for biotechnology, clinical chemistry, proteomics, and systems biology. The reference method to quantify peptides and proteins is amino acid analysis (AAA). This consists of an acidic hydrolysis followed by chromatographic separation and spectrophotometric detection of amino acids. Although widely used, this method displays some limitations, in particular the need for large amounts of starting material. Driven by the need to quantify isotope-dilution standards used for absolute quantitative proteomics, particularly stable isotope-labeled (SIL) peptides and PSAQ proteins, we developed a new AAA assay (AAA-MS). This method requires neither derivatization nor chromatographic separation of amino acids. It is based on rapid microwave-assisted acidic hydrolysis followed by high-resolution mass spectrometry analysis of amino acids. Quantification is performed by comparing MS signals from labeled amino acids (SIL peptide- and PSAQ-derived) with those of unlabeled amino acids originating from co-hydrolyzed NIST standard reference materials. For both SIL peptides and PSAQ standards, AAA-MS quantification results were consistent with classical AAA measurements. Compared to AAA assay, AAA-MS was much faster and was 100-fold more sensitive for peptide and protein quantification. Finally, thanks to the development of a labeled protein standard, we also extended AAA-MS analysis to the quantification of unlabeled proteins.

  19. Antimicrobial Susceptibility of Flavobacterium psychrophilum from Chilean Salmon Farms and Their Epidemiological Cut-Off Values Using Agar Dilution and Disk Diffusion Methods.

    Science.gov (United States)

    Miranda, Claudio D; Smith, Peter; Rojas, Rodrigo; Contreras-Lynch, Sergio; Vega, J M Alonso

    2016-01-01

    Flavobacterium psychrophilum is the most important bacterial pathogen for freshwater farmed salmonids in Chile. The aims of this study were to determine the susceptibility to antimicrobials used in fish farming of Chilean isolates and to calculate their epidemiological cut-off (CO WT ) values. A number of 125 Chilean isolates of F. psychrophilum were isolated from reared salmonids presenting clinical symptoms indicative of flavobacteriosis and their identities were confirmed by 16S rRNA polymerase chain reaction. Susceptibility to antibacterials was tested on diluted Mueller-Hinton by using an agar dilution MIC method and a disk diffusion method. The CO WT values calculated by Normalized Resistance Interpretation (NRI) analysis allow isolates to be categorized either as wild-type fully susceptible (WT) or as manifesting reduced susceptibility (NWT). When MIC data was used, NRI analysis calculated a CO WT of ≤0.125, ≤2, and ≤0.5 μg mL -1 for amoxicillin, florfenicol, and oxytetracycline, respectively. For the quinolones, the CO WT were ≤1, ≤0.5, and ≤0.125 μg mL -1 for oxolinic acid, flumequine, and enrofloxacin, respectively. The disk diffusion data sets obtained in this work were extremely diverse and were spread over a wide range. For the quinolones there was a close agreement between the frequencies of NWT isolates calculated using MIC and disk data. For oxolinic acid, flumequine, and enrofloxacin the frequencies were 45, 39, and 38% using MIC data, and 42, 41, and 44%, when disk data were used. There was less agreement with the other antimicrobials, because NWT frequencies obtained using MIC and disk data, respectively, were 24 and 10% for amoxicillin, 8 and 2% for florfenicol, and 70 and 64% for oxytetracycline. Considering that the MIC data was more precise than the disk diffusion data, MIC determination would be the preferred method for susceptibility testing for this species and the NWT frequencies derived from the MIC data sets should be

  20. Antimicrobial Susceptibility of Flavobacterium psychrophilum from Chilean Salmon Farms and their Epidemiological Cut-off Values using Agar Dilution and Disk Diffusion Methods

    Directory of Open Access Journals (Sweden)

    Claudio D Miranda

    2016-11-01

    Full Text Available Flavobacterium psychrophilum is the most important bacterial pathogen for freshwater farmed salmonids in Chile. The aims of this study were to determine the susceptibility to antimicrobials used in fish farming of Chilean isolates and to calculate their epidemiological cut-off (COWT values. A number of 125 Chilean isolates of F. psychrophilum were isolated from reared salmonids presenting clinical symptoms indicative of flavobacteriosis and their identities were confirmed by 16S rRNA polymerase chain reaction. Susceptibility to antibacterials was tested on diluted Mueller-Hinton by using an agar dilution MIC method and a disk diffusion method. The COWT values calculated by Normalised Resistance Interpretation (NRI analysis allow isolates to be categorized either as wild-type fully susceptible (WT or as manifesting reduced susceptibility (NWT. When MIC data was used, NRI analysis calculated a COWT of ≤ 0.125 μg mL-1, ≤ 2 μg mL-1 and ≤ 0.5 μg mL-1 for amoxicillin, florfenicol and oxytetracycline, respectively. For the quinolones, the COWT were ≤1 μg mL-1, ≤ 0.5 μg mL-1 and ≤ 0.125 μg mL-1 for oxolinic acid, flumequine and enrofloxacin respectively. The disc diffusion data sets obtained in this work were extremely diverse and were spread over a wide range. For the quinolones there was a close agreement between the frequencies of NWT isolates calculated using MIC and disc data. For oxolinic acid, flumequine and enrofloxacin the frequencies were 45, 39 and 38% using MIC data, and 42, 41 and 44%, when disc data were used. There was less agreement with the other antimicrobials, because NWT frequencies obtained using MIC and disc data respectively, were 24% and 10% for amoxicillin, 8% and 2% for florfenicol and 70% and 64% for oxytetracycline. Considering that the MIC data was more precise than the disc diffusion data, MIC determination would be the preferred method for susceptibility testing for this species and the NWT frequencies

  1. Simple and rapid analytical method for detection of amino acids in blood using blood spot on filter paper, fast-GC/MS and isotope dilution technique.

    Science.gov (United States)

    Kawana, Shuichi; Nakagawa, Katsuhiro; Hasegawa, Yuki; Yamaguchi, Seiji

    2010-11-15

    A simple and rapid method for quantitative analysis of amino acids, including valine (Val), leucine (Leu), isoleucine (Ile), methionine (Met) and phenylalanine (Phe), in whole blood has been developed using GC/MS. In this method, whole blood was collected using a filter paper technique, and a 1/8 in. blood spot punch was used for sample preparation. Amino acids were extracted from the sample, and the extracts were purified using cation-exchange resins. The isotope dilution method using ²H₈-Val, ²H₃-Leu, ²H₃-Met and ²H₅-Phe as internal standards was applied. Following propyl chloroformate derivatization, the derivatives were analyzed using fast-GC/MS. The extraction recoveries using these techniques ranged from 69.8% to 87.9%, and analysis time for each sample was approximately 26 min. Calibration curves at concentrations from 0.0 to 1666.7 μmol/l for Val, Leu, Ile and Phe and from 0.0 to 333.3 μmol/l for Met showed good linearity with regression coefficients=1. The method detection limits for Val, Leu, Ile, Met and Phe were 24.2, 16.7, 8.7, 1.5 and 12.9 μmol/l, respectively. This method was applied to blood spot samples obtained from patients with phenylketonuria (PKU), maple syrup urine disease (MSUD), hypermethionine and neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD), and the analysis results showed that the concentrations of amino acids that characterize these diseases were increased. These results indicate that this method provides a simple and rapid procedure for precise determination of amino acids in whole blood. Copyright © 2010 Elsevier B.V. All rights reserved.

  2. Validation of a dilute and shoot method for quantification of 12 elements by inductively coupled plasma tandem mass spectrometry in human milk and in cow milk preparations.

    Science.gov (United States)

    Dubascoux, Stéphane; Andrey, Daniel; Vigo, Mario; Kastenmayer, Peter; Poitevin, Eric

    2018-09-01

    Nutritional information about human milk is essential as early human growth and development have been closely linked to the status and requirements of several macro- and micro-elements. However, methods addressing whole mineral profiling in human milk have been scarce due in part to their technical complexities to accurately and simultaneously measure the concentration of micro- and macro-trace elements in low volume of human milk. In the present study, a single laboratory validation has been performed using a "dilute and shoot" approach for the quantification of sodium (Na), magnesium (Mg), phosphorus (P), potassium (K), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), selenium (Se), molybdenum (Mo) and iodine (I), in both human milk and milk preparations. Performances in terms of limits of detection and quantification, of repeatability, reproducibility and trueness have been assessed and verified using various reference or certified materials. For certified human milk sample (NIST 1953), recoveries obtained for reference or spiked values are ranged from 93% to 108% (except for Mn at 151%). This robust method using new technology ICP-MS/MS without high pressure digestion is adapted to both routinely and rapidly analyze human milk micro-sample (i.e. less than 250 μL) in the frame of clinical trials but also to be extended to the mineral profiling of milk preparations like infant formula and adult nutritionals. Copyright © 2018 Elsevier GmbH. All rights reserved.

  3. Determination of steroid hormones in a human-serum reference material by isotope dilution--mass spectrometry: A candidate definitive method for cortisol

    International Nuclear Information System (INIS)

    Patterson, D.G.; Patterson, M.B.; Culbreth, P.H.; Fast, D.M.; Holler, J.S.; Sampson, E.J.; Bayse, D.D.

    1984-01-01

    We report a method, based on isotope dilution--mass spectrometry, for determining cortisol in a pooled specimen of human serum. Isotopically labeled cortisol is added to 5.0 mL of serum so that the molar concentrations of labeled cortisol and unlabeled cortisol are approximately equal. The specimen and two calibration standards are extracted with dichloromethane, and the extracted cortisol is converted to the methoxime-trimethylsilyl ether derivative. Samples and standards are analyzed by gas chromatography--mass spectrometry by monitoring the peak areas for m/z 605 and 608. The cortisol concentration is calculated by linear interpolation between the two bracketing standards. Variances of data collected during six weeks showed that the overall coefficient of variation (CV) was 0.69% (n . 32); the within-vial CV, 0.63%; the among-vial CV, 0.22%; and the among-day CV, 0.15% (means . 3.973 nmol/vial). Method specificity was demonstrated by liquid chromatographic as well as C 8 mini-column cleanup of samples before derivation, by alternative ion monitoring at m/z 636 and 639, and by negative-ion chemical ionization at m/z 459 and 462. Derivatives of all observed degradation products of cortisol under basic, neutral, and acidic conditions did not interfere

  4. Stable isotope dilution HILIC-MS/MS method for accurate quantification of glutamic acid, glutamine, pyroglutamic acid, GABA and theanine in mouse brain tissues.

    Science.gov (United States)

    Inoue, Koichi; Miyazaki, Yasuto; Unno, Keiko; Min, Jun Zhe; Todoroki, Kenichiro; Toyo'oka, Toshimasa

    2016-01-01

    In this study, we developed the stable isotope dilution hydrophilic interaction liquid chromatography with tandem mass spectrometry (HILIC-MS/MS) technique for the accurate, reasonable and simultaneous quantification of glutamic acid (Glu), glutamine (Gln), pyroglutamic acid (pGlu), γ-aminobutyric acid (GABA) and theanine in mouse brain tissues. The quantification of these analytes was accomplished using stable isotope internal standards and the HILIC separating mode to fully correct the intramolecular cyclization during the electrospray ionization. It was shown that linear calibrations were available with high coefficients of correlation (r(2)  > 0.999, range from 10 pmol/mL to 50 mol/mL). For application of the theanine intake, the determination of Glu, Gln, pGlu, GABA and theanine in the hippocampus and central cortex tissues was performed based on our developed method. In the region of the hippocampus, the concentration levels of Glu and pGlu were significantly reduced during reality-based theanine intake. Conversely, the concentration level of GABA increased. This result showed that transited theanine has an effect on the metabolic balance of Glu analogs in the hippocampus. Copyright © 2015 John Wiley & Sons, Ltd.

  5. Method for the detection of Tc in seaweed samples coupling the use of Re as a chemical tracer and isotope dilution inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Mas, Jose Luis; Tagami, Keiko; Uchida, Shigeo

    2004-01-01

    Analysis of the artificial radionuclide 99 Tc in environmental samples requires a chemical separation due to its low concentration, and therefore the use of a chemical yield tracer is peremptory. From a practical viewpoint, Re can be used for this purpose, due to its chemical similarities with Tc. Thus, the use of a radioactive tracer for Tc recovery calculation can be avoided. However, results from a recent intercomparison exercise showed that using of Re as a chemical yield tracer appears to underestimate the Tc concentration relative to the result obtained with isotopes of Tc. In the present work, the methodology used to design a simple separation method for the measurement of 99 Tc in environmental samples is described. Tc recovery is estimated throughout the Re recovery calculation by the isotope dilution technique coupled with ICP-MS (ID-ICP-MS) technique. For chemical separation, a chromatographic resin is used. Interfering elements are removed using a resin washing step carefully designed to avoid any element fractionation between Re and Tc; the care taken in this step is of major importance to assure the equivalence of the chemical recoveries for both elements. Agreement is tested using five replicates of five seaweed samples. The average recoveries for 95m Tc and Re were 93±6 and 95±7%, respectively, those are within the uncertainty intervals for each other. The results explained here demonstrate the possibility of applying Re chemical recoveries to calculate the Tc concentrations with the advantage of not introducing systematic errors

  6. Significance of Herbaspirillum seropedicae inoculation and/or straw amendment on growth and dinitrogen fixation of wheat using 15N-dilution method.

    Science.gov (United States)

    el-Komy, H M; Saad, O A; Hetta, A M

    2003-01-01

    The effect of Herbaspirillum seropedicae inoculation and/or maize straw (0, 5 and 10 Mg/hm2) amendment on the growth and N2 fixation of wheat was determined in pot experiments using 15N-dilution method. Inoculation resulted in accumulation of fixed nitrogen, and % N from atmosphere being 24.6 and 26.5% in wheat shoot and grain, respectively. Straw amendment reduced % Natm to 16.1 and 20.2% at high straw level (10 Mg/hm2). Rational nitrogen fertilization (180 kg N/hm2) completely inhibited N2 fixation by H. seropedicae inoculation. Bacterial inoculation increased dry shoot and grain yield up to 23 and 31%, respectively. The highest levels of shoot and grain dry mass (46.5 and 42.4%) were obtained by N-fertilization in both inoculated and uninoculated plants. Total shoot and grain N-yield increased irrespective of organic matter amendment by inoculation up to 9 and 25%, respectively. N-fertilized plants recorded a maximum increase in N-yield (57 and 51%). H. seropedicae was reisolated from inoculated wheat histosphere after harvesting (90 d from sowing). Neither organic matter nor mineral nitrogen applications had any marked effect on bacterial total counts colonizing wheat histosphere. Moreover, no symptoms of mottled stripe disease were observed on leaves and stems of inoculated plants.

  7. Evaluation of the isotopic dilution method with addition of 15 N fertilizer to the soil, for quantification of BNF by legumes

    International Nuclear Information System (INIS)

    Morales, E.R.B.

    1990-01-01

    Two pot experiments were carried out in greenhouse, with the objective of evaluating the isotopic dilution method with the addition of 15 N fertilizer to the soil for evaluation of biological nitrogen fixation (BNF) by legumes. Experiment I: with addition of 15 N-fertilizer, according to FRIED and MIDDELBOE (1977), and Experiment II: Without adding the fertilizer, by natural variation of 15 N (δ 15 N). In experiment I, the following crops were utilized as test plants: soybean, bean and cowpea and for the control plants: non nodulating soybean, rice and wheat, with distinct number of plants per pot. The pots containing 8 Kg a Dark red latossol (LE) of Sao Paulo state, Brazil, received the same rate of nitrogen fertilizer with same 15 N enrichment. In experiment II, bean was utilized as test crop and non nodulating soybean and rice as controls, and they did not receive any nitrogen fertilizer. The experiments lasted 81 days, from July to October 1989. The above ground parts of the plants were harvested, for which dry matter weight, total-N and 15 N were determined. (author)

  8. Plutonium determination by isotope dilution

    International Nuclear Information System (INIS)

    Lucas, M.

    1980-01-01

    The principle is to add to a known amount of the analysed solution a known amount of a spike solution consisting of plutonium 242. The isotopic composition of the resulting mixture is then determined by surface ionization mass spectrometry, and the plutonium concentration in the solution is deduced, from this measurement. For irradiated fuels neutronic studies or for fissile materials balance measurements, requiring the knowledge of the ratio U/Pu or of concentration both uranium and plutonium, it is better to use the double spike isotope dilution method, with a spike solution of known 233 U- 242 Pu ratio. Using this method, the ratio of uranium to plutonium concentration in the irradiated fuel solution can be determined without any accurate measurement of the mixed amounts of sample and spike solutions. For fissile material balance measurements, the uranium concentration is determined by using single isotope dilution, and the plutonium concentration is deduced from the ratio Pu/U and U concentration. The main advantages of isotope dilution are its selectivity, accuracy and very high sensitivity. The recent improvements made to surface ionization mass spectrometers have considerably increased the precision of the measurements; a relative precision of about 0.2% to 0.3% is obtained currently, but it could be reduced to 0.1%, in the future, with a careful control of the experimental procedures. The detection limite is around 0.1 ppb [fr

  9. Hybridizing pines with diluted pollen

    Science.gov (United States)

    Robert Z. Callaham

    1967-01-01

    Diluted pollens would have many uses by the tree breeder. Dilutions would be particularly advantageous in making many controlled pollinations with a limited amount of pollen. They also would be useful in artificial mass pollinations of orchards or single trees. Diluted pollens might help overcome troublesome genetic barriers to crossing. Feasibility o,f using diluted...

  10. Helium dilution refrigerator

    International Nuclear Information System (INIS)

    1973-01-01

    A new system of continuous heat exchange for a helium dilution refrigerator is proposed. The 3 He effluent tube is concurrent with the affluent mixed helium tube in a vertical downward direction. Heat exchange efficiency is enhanced by placing in series a number of elements with an enlarged surface area

  11. Isotope dilution analysis

    Energy Technology Data Exchange (ETDEWEB)

    Fudge, A.

    1978-12-15

    The following aspects of isotope dilution analysis are covered in this report: fundamental aspects of the technique; elements of interest in the nuclear field, choice and standardization of spike nuclide; pre-treatment to achieve isotopic exchange and chemical separation; sensitivity; selectivity; and accuracy.

  12. Dissolution rates of unirradiated UO2, UO2 doped with 233U, and spent fuel under normal atmospheric conditions and under reducing conditions using an isotope dilution method

    International Nuclear Information System (INIS)

    Ollila, Kaija; Albinsson, Yngve; Oversby, Virginia; Cowper, Mark

    2003-10-01

    The experimental results given in this report allow us to draw the following conclusions. 1) Tests using unirradiated fuel pellet materials from two different manufacturers gave very different dissolution rates under air atmosphere testing. Tests for fragments of pellets from different pellets made by the same manufacturer gave good agreement. This indicates that details of the manufacturing process have a large effect on the behavior of unirradiated UO 2 in dissolution experiments. Care must be taken in interpreting differences in results obtained in different laboratories because the results may be affected by manufacturing effects. 2) Long-term tests under air atmosphere have begun to show the effects of precipitation. Further testing will be needed before the samples reach steady state. 3) Testing of unirradiated UO 2 in systems containing an iron strip to produce reducing conditions gave [U] less than detection limits ( 235 U added as spike was recovered, indicating that 90% of the spike had precipitated onto the solid sample or the iron strip. 9) Tests of UO 2 pellet materials containing 233 U to provide an alpha decay activity similar to that expected for spent fuel 3000 and 10,000 years after disposal showed that the pellet materials behaved as expected under air atmosphere conditions, showing that the manufacturing method was successful. 10) Early testing of the 233 U-doped materials under reducing conditions showed relatively rapid (30 minute) dissolution of small amounts of U at the start of the puff test procedure. Results of analyses of an acidified fraction of the same solutions after 1 or 2 weeks holding indicate that the solutions were inhomogeneous, indicating the presence of colloidal material or small grains of solid. 11) Samples from the 233 U-doped tests initially indicated dissolution of solid during the first week of testing, with some indication of more rapid dissolution of the material with the higher doping. 12) The second cycle of testing

  13. Estabilidad física y química de preparaciones líquidas extemporáneas elaboradas a partir de tabletas de captopril

    OpenAIRE

    Olaya, Maria del Pilar; Muñoz, Ilvar José; Ponce D´León, Luisa Fernanda; Barbosa, Helber; Bautista, Sandra Elizabeth

    2008-01-01

    Se estudió la estabilidad de preparaciones líquidas extemporáneas para administración peroral, elaboradas  a partir de tabletas de captopril de dos marcas comerciales del mercado nacional colombiano, codificadas como A y B, utilizando solventes de uso común en hospitales. Vehículo 1: agua destilada + vitamina C 10 %  (98 % : 2 %), Vehículo 2: dextrosa 10 % en agua destilada + vitamina C 10 % (98 % : 2 %). Las muestras fueron almacenadas a 5 ºC, 25 ºC y 40 ºC. La cuantificación del fármaco se ...

  14. La preparacion en ciencia de los candidatos a maestros del nivel elemental primario segun la reforma de la educacion cientifica en Puerto Rico: Una propuesta de secuencia curricular

    Science.gov (United States)

    Rodriguez Plaza, Evelyn

    El proposito de esta investigacion fue identificar los componentes de la preparacion en ciencia que deben recibir los estudiantes del Bachillerato en Artes en Educacion Elemental, Nivel Primario, de acuerdo a los documentos que dirigen la reforma de la educacion cientifica en Puerto Rico. Tambien, se identificaron los componentes de los cursos que forman parte de la preparacion en ciencia de estos estudiantes. Se compararon los componentes de la preparacion en ciencia y los componentes de los cursos para determinar congruencias y discrepancias. Con los datos recopilados se identificaron los componentes de los cursos de una secuencia curricular para la preparacion en ciencia de los candidatos a maestros del nivel elemental primario. La secuencia curricular que se propone en esta investigacion incluye cursos de contenido cientifico y de metodologia en la ensenanza de la ciencia disenados para satisfacer las necesidades de los candidatos. Se recomienda que en los procesos para el diseno, la implantacion y la evaluacion de estos cursos participen profesores de ciencia, profesores de educacion y maestros del nivel elemental primario. Todos los cursos de la secuencia curricular deben tener un enfoque constructivista. Las experiencias educativas que se incluyan en los cursos deben aspirar a desarrollar en los candidatos los atributos de la cultura cientifica y actitudes positivas hacia la ciencia y hacia la ensenanza de esta disciplina. El modelaje por parte de los profesores que ensenen los cursos de la secuencia curricular es fundamental en el desarrollo profesional de los candidatos. Se recomienda que en los cursos de contenido cientifico se estudien los conceptos y los conocimientos cientificos que forman parte del curriculo de Kindergarten a tercer grado de forma integrada y con una profundidad universitaria. Estos cursos deben tener un enfoque interdisciplinario e incluir el estudio de la naturaleza de la ciencia y un componente de laboratorio para desarrollar los

  15. Labile pools of Pb in vegetable-growing soils investigated by an isotope dilution method and its influence on soil pH.

    Science.gov (United States)

    Xie, Hong; Huang, Zhi-Yong; Cao, Ying-Lan; Cai, Chao; Zeng, Xiang-Cheng; Li, Jian

    2012-08-01

    Pollution of Pb in the surface of agricultural soils is of increasing concern due to its serious impact on the plant growth and the human health through the food chain. However, the mobility, activity and bioavailability of Pb rely mainly on its various chemical species in soils. In the present study, E and L values, the labile pools of isotopically exchangeable Pb, were estimated using the method of isotope dilution in three vegetable-growing soils. The experiments involved adding a stable enriched isotope ((206)Pb > 96%) to a soil suspension and to soils in which plants are subsequently grown, the labile pools of Pb were then estimated by measuring the isotopic composition of Pb in soil solutions and in the plant tissues, respectively. In addition, the correlation of E values and soil pH was investigated at the ranges of pH 4.5-7.0. The amount of labile Pb in soils was also estimated using different single chemical extractants and a modified BCR approach. The results showed that after spiking the enriched isotopes of (206)Pb (>96%) for 24 hours an equilibration of isotopic exchanges in soil suspensions was achieved, and the isotope ratios of (208)Pb/(206)Pb measured at that time was used for calculating the E(24 h) values. The labile pools of Pb by %E(24 h) values, ranging from 53.2% to 61.7% with an average 57%, were found to be significantly higher (p soil pH was found in the tested soil sample. The results indicate that the %E(24 h) value can more rapidly and easily predict the labile pools of Pb in soils compared with L values, but it might be readily overestimated because of the artificial soil acidity derived from the spiked isotopic tracer and the excess of spiked enriched isotopes. The results also suggest that the amounts of Pb extracted with EDTA and the Σ(BCR) values extracted with the modified BCR approach are helpful to detect the labile pools of Pb in soils. In addition, the negative correlation between soil pH and the labile pools of Pb in soils

  16. Defects in dilute nitrides

    International Nuclear Information System (INIS)

    Chen, W.M.; Buyanova, I.A.; Tu, C.W.; Yonezu, H.

    2005-01-01

    We provide a brief review our recent results from optically detected magnetic resonance studies of grown-in non-radiative defects in dilute nitrides, i.e. Ga(In)NAs and Ga(Al,In)NP. Defect complexes involving intrinsic defects such as As Ga antisites and Ga i self interstitials were positively identified.Effects of growth conditions, chemical compositions and post-growth treatments on formation of the defects are closely examined. These grown-in defects are shown to play an important role in non-radiative carrier recombination and thus in degrading optical quality of the alloys, harmful to performance of potential optoelectronic and photonic devices based on these dilute nitrides. (author)

  17. Studies of diluted antiferromagnets MnxMg1-xTiO3 with x=0.55 and 0.70 by muon spin relaxation method

    International Nuclear Information System (INIS)

    Fukaya, A.; Ito, A.; Torikai, E.; Nishiyama, K.; Nagamine, K.

    1997-01-01

    Longitudinal fields μSR measurements have been performed in order to probe the spin dynamics in the diluted antiferromagnets Mn x Mg 1-x TiO 3 with x=0.70 and 0.55. In the x=0.70 sample which forms the antiferromagnetic long-range order, the static and fluctuating fields coexist at the muon stopping site below T N . On the other hand, in the x=0.55 sample which shows the spin-glass behavior, the local fields fluctuate rather fast even below T SG . We infer that this drastic change occurs when Mn x Mg 1-x TiO 3 transforms from an antiferromagnetic system to a spin-glass system by dilution

  18. Estudo comparativo entre as técnicas de diluição em caldo e diluição em ágar, nos antibiogramas para Candida: a comparative study Broth dilution and agar dilution methods applied to Candida sensitivity tests

    Directory of Open Access Journals (Sweden)

    Sydney Hartz Alves

    1992-06-01

    Full Text Available Os autores compararam o desempenho das técnicas de diluição em caldo e diluição em ágar, mediante a determinação da CIM (concentração inibitória mínima e da CFM (concentração fungicida mínima de antifúngicos poliênicos e imidazólicos, frente a diversas espécies de Candida. A concordância entre as técnicas foi variável em função do antifúngico utilizado. Os melhores percentuais de concordância ocorreram quando se realizou o teste com poliênicos. Os autores discutem aspectos que envolvem a problemática dos testes de sensibilidade de leveduras a antifúngicosThe performance of broth dilution method and agar dilution method were compared by MIC (minimal inhibitory concentration and MFC (minimal fungicidal concentration from Candida strains to polyene and imizadole anti-fungal agents. The concordance between these methods was drug dependent. The best percent of concordance were showed when the polyenes were tested. The problems of sensitivity test for yeasts to antifungal drugs are discussed

  19. Gluconeogenesis from labeled carbon: estimating isotope dilution

    International Nuclear Information System (INIS)

    Kelleher, J.K.

    1986-01-01

    To estimate the rate of gluconeogenesis from steady-state incorporation of labeled 3-carbon precursors into glucose, isotope dilution must be considered so that the rate of labeling of glucose can be quantitatively converted to the rate of gluconeogenesis. An expression for the value of this isotope dilution can be derived using mathematical techniques and a model of the tricarboxylic acid (TCA) cycle. The present investigation employs a more complex model than that used in previous studies. This model includes the following pathways that may affect the correction for isotope dilution: 1) flux of 3-carbon precursor to the oxaloacetate pool via acetyl-CoA and the TCA cycle; 2) flux of 4- or 5-carbon compounds into the TCA cycle; 3) reversible flux between oxaloacetate (OAA) and pyruvate and between OAA and fumarate; 4) incomplete equilibrium between OAA pools; and 5) isotope dilution of 3-carbon tracers between the experimentally measured pool and the precursor for the TCA-cycle OAA pool. Experimental tests are outlined which investigators can use to determine whether these pathways are significant in a specific steady-state system. The study indicated that flux through these five pathways can significantly affect the correction for isotope dilution. To correct for the effects of these pathways an alternative method for calculating isotope dilution is proposed using citrate to relate the specific activities of acetyl-CoA and OAA

  20. Method development for the determination of cadmium, copper, lead, selenium and thallium in sediments by slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry and isotopic dilution calibration

    International Nuclear Information System (INIS)

    Dias, Lucia Felicidade; Miranda, Gilson R.; Saint'Pierre, Tatiana D.; Maia, Sandra M.; Frescura, Vera L.A.; Curtius, Adilson J.

    2005-01-01

    A procedure for the determination of Cd, Cu, Pb, Se and Tl by slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS) with calibration by isotopic dilution is proposed. The slurry is prepared by mixing the sample with diluted nitric and hydrofluoric acids in an ultrasonic bath and then in a water bath at 60 deg C for 120 min. The slurries were let to stand at least for 12 h, manually shaken before poured into the autosampler cups and homogenized by passing through an argon flow, just before pipetting it into the furnace. The analytes were determined in two groups, according to their thermal behaviors. The furnace temperature program was optimized and the selected compromised pyrolysis temperatures were: 400 deg C for Cd, Se and Tl and 700 deg C for Cu and Pb. The vaporization temperature was 2300 deg C. The analyses were carried out without modifier as no significant effect was observed for different tested modifiers. Different sample particle sizes did not affect the sensitivity significantly, then a particle size ≤50 μm was adopted. The accuracy was checked by analyzing five certified reference sediments, with analytes concentrations from sub-μg g -1 to a few hundreds μg g -1 . The great majority of the obtained concentrations were in agreement with the certified values. The detection limits, determined for the MESS-2 certified sediment, were, in μg g -1 : 0.01 for Cd; 0.8 for Cu; 0.4 for Pb; 0.4 for Se and 0.06 for Tl. The precision was adequate with relative standard deviations lower than 12%. Isotopic dilution showed to be an efficient calibration technique for slurry, as the extraction of the analyte to the liquid phase of the slurry and the reactions in the vaporizer must help the equilibration between the added isotope and the isotope in the sample

  1. Dinitrogen fixation in white clover grown in pure stand and mixture with ryegrass estimated by the immobilized 15N isotope dilution method

    DEFF Research Database (Denmark)

    Jørgensen, F.V.; Jensen, E.S.; Schjørring, J.K.

    1999-01-01

    Dinitrogen fixation in white clover (Trifolium repens L.) grown in pure stand and mixture with perennial ryegrass (Lolium perenne L.) was determined in the field using N-15 isotope dilution and harvest of the shoots. The apparent transfer of clover N to perennial ryegrass was simultaneously...... assessed. The soil was labelled either by immobilizing N-15 in organic matter prior to establishment of the sward or by using the conventional labelling procedure in which N-15 fertilizer is added after sward establishment. Immobilization of N-15 in the soil organic matter has not previously been used...

  2. Development of multi-residue method for the determination of pesticides in cereal matrices by isotopic dilution associated to liquid chromatography coupled to tandem mass spectrometry after pressurized liquid extraction

    International Nuclear Information System (INIS)

    El Mrabet, Khadija

    2008-01-01

    Pesticides are nowadays considered as toxic for human health. The maximal residues levels authorized in water and foodstuff are more and more strict. Therefore, selective analytical techniques are necessary for their identification and their quantification. The aim of this thesis was to develop a multi-residue method for the determination of pesticides by isotopic dilution associated to liquid chromatography (LC) coupled with tandem mass spectrometry (MS"2) after pressurized liquid extraction. In a first step, an analysis method of phenyl-ureas and triazines in groundwater by isotopic dilution associated to LC/MS"2 after solid phase extraction has been developed. The method has been validated and evaluated by participating to an inter-laboratory study. Concerning cereals, an extraction method of pesticides associated to an analysis by LC/MS"2 has been developed for thirty-eight pesticides representative of twenty-six chemicals families and fourteen labeled compounds in wheat. The analysis has been carried out in reversed phase chromatography. Separation and detection conditions have been optimized. A global analytical protocol consisting of a pressurized liquid extraction step using acetonitrile at 100 deg. C and at 100 bars and followed by purification step of the resulting extract on a polymeric sorbent was developed. The developed method enables to extract thirty-eight pesticides and fourteen labeled compounds from wheat with recovery yield about 85% (RSD =4%, n=3). Moreover, the results show that the application of isotopic dilution can be complex. Although some improvements need to be added regarding experimentation of aged matrices or contaminated samples, the potential of the method has been demonstrated. (author) [fr

  3. Composite systems of dilute and dense couplings

    International Nuclear Information System (INIS)

    Raymond, J R; Saad, D

    2008-01-01

    Composite systems, where couplings are of two types, a combination of strong dilute and weak dense couplings of Ising spins, are examined through the replica method. The dilute and dense parts are considered to have independent canonical disordered or uniform bond distributions; mixing the models by variation of a parameter γ alongside inverse temperature β we analyse the respective thermodynamic solutions. We describe the variation in high temperature transitions as mixing occurs; in the vicinity of these transitions we exactly analyse the competing effects of the dense and sparse models. By using the replica symmetric ansatz and population dynamics we described the low temperature behaviour of mixed systems

  4. Diluted magnetic semiconductor nanowires exhibiting magnetoresistance

    Science.gov (United States)

    Yang, Peidong [El Cerrito, CA; Choi, Heonjin [Seoul, KR; Lee, Sangkwon [Daejeon, KR; He, Rongrui [Albany, CA; Zhang, Yanfeng [El Cerrito, CA; Kuykendal, Tevye [Berkeley, CA; Pauzauskie, Peter [Berkeley, CA

    2011-08-23

    A method for is disclosed for fabricating diluted magnetic semiconductor (DMS) nanowires by providing a catalyst-coated substrate and subjecting at least a portion of the substrate to a semiconductor, and dopant via chloride-based vapor transport to synthesize the nanowires. Using this novel chloride-based chemical vapor transport process, single crystalline diluted magnetic semiconductor nanowires Ga.sub.1-xMn.sub.xN (x=0.07) were synthesized. The nanowires, which have diameters of .about.10 nm to 100 nm and lengths of up to tens of micrometers, show ferromagnetism with Curie temperature above room temperature, and magnetoresistance up to 250 Kelvin.

  5. Atomic displacements in bcc dilute alloys

    Indian Academy of Sciences (India)

    We present here a systematic investigation of the atomic displacements in bcc transition metal (TM) dilute alloys. We have calculated the atomic displacements in bcc (V, Cr, Fe, Nb, Mo, Ta and W) transition metals (TMs) due to 3d, 4d and 5d TMs at the substitutional site using the Kanzaki lattice static method. Wills and ...

  6. Dilute acid/metal salt hydrolysis of lignocellulosics

    Science.gov (United States)

    Nguyen, Quang A.; Tucker, Melvin P.

    2002-01-01

    A modified dilute acid method of hydrolyzing the cellulose and hemicellulose in lignocellulosic material under conditions to obtain higher overall fermentable sugar yields than is obtainable using dilute acid alone, comprising: impregnating a lignocellulosic feedstock with a mixture of an amount of aqueous solution of a dilute acid catalyst and a metal salt catalyst sufficient to provide higher overall fermentable sugar yields than is obtainable when hydrolyzing with dilute acid alone; loading the impregnated lignocellulosic feedstock into a reactor and heating for a sufficient period of time to hydrolyze substantially all of the hemicellulose and greater than 45% of the cellulose to water soluble sugars; and recovering the water soluble sugars.

  7. Preparation of naphtalene monocrystals for scintillometers; Preparacion de monocristales de naftaleno para contadores de centelleo

    Energy Technology Data Exchange (ETDEWEB)

    Gaeta, R

    1959-07-01

    A method to prepare naphthalene crystals for scintillometers is described. The different methods of preparation and the reasons to choose the Bridgman method are analysed. The thermal curves of the growing furnaces, blister shape, use of curved capillaries and the most convenient growing velocities are studied in detail. Methods of preparation of high purity naphthalene by means of chromatography and zone melting are described. Finally the operations of cutting and polishing of crystal and their most significant physics properties are studied. (Author) 28 refs.

  8. A non-destructive method of determination of biomass of mango (Mangifera indica L.) and guava trees using principle of isotope dilution

    International Nuclear Information System (INIS)

    Kotur, S.C.; Keshava Murthy, S.V.

    2004-01-01

    Biomass of 4-year old trees 'Alphonso' mango was estimated by injecting carrier- free 32 P into the trunk followed by radioassay of the isotope after a complete dilution of 32 P in the tree (3 months after injection). The isotopically calculated plant volume (56.903 - 68.981 m 3 x10 3 ) and biomass (31.70 - 36.23 gx 10 -3 ) showed good agreement but generally overestimated both by about 19 per cent compared to the actual values determined physically (43.720 - 60.693 m 3 x10 3 and 22.88 - 34.78 gx 10 -3 , respectively). Application of the technique in a set of four 15-year old mango trees yielded volume estimates of 170.749 - 175.835 m 3 x10 3 (mean 173.512 ± 1.12 per cent) and biomass estimates of 73.0 - 87.4 gx10 -3 (mean = 80.32 ± 6.79 per cent). In another set of four 12-year old guava trees the corresponding values were 40.165 to 44.014 m 3 x10 3 (mean = 41.743 ± 3.42 per cent) and 22.252 gxl0 -3 (mean = 23.210 ± 2.95 per cent) respectively. The technique is of promise in fertilizer use efficiency and nutrient dynamics studies in tree crops. (author)

  9. Dietary vitamin A intakes of Filipino elders with adequate or low liver vitamin A concentrations as assessed by the deuterated-retinol-dilution method: implications for dietary requirements.

    Science.gov (United States)

    Ribaya-Mercado, Judy D; Solon, Florentino S; Fermin, Liza S; Perfecto, Christine S; Solon, Juan Antonio A; Dolnikowski, Gregory G; Russell, Robert M

    2004-04-01

    The vitamin A requirements of elderly humans have not been studied. In a cross-sectional study of 60-88-y-old men (n = 31) and women (n = 31) in rural Philippines, we assessed the dietary intakes of elders with adequate (> or = 0.07 micromol/g) or low (value for elders. The mean (+/- SD) vitamin A intakes of the men and women with adequate vitamin A in liver were 135 +/- 86 and 134 +/- 104 microg retinol activity equivalents (RAE)/d, respectively; intakes of the men and women with low vitamin A in liver were 75 +/- 53 and 60 +/- 27 microg RAE/d, respectively. Total-body vitamin A or liver vitamin A but not serum retinol correlated with dietary RAE, preformed vitamin A, beta-carotene, fat, and protein. An estimated acceptable or sufficient dietary vitamin A intake associated with adequate liver vitamin A concentrations in elders is 6.45 microg RAE/kg body wt; for a reference 76-kg man and a 61-kg woman, these values are approximately 500 and 400 microg RAE/d, respectively. The dietary vitamin A intakes of elders with adequate or low liver vitamin A concentrations as estimated by use of the deuterated-retinol-dilution technique are useful for assessing vitamin A requirements.

  10. The Melt-Dilute Treatment Technology Offgas Development Status Report

    International Nuclear Information System (INIS)

    Adams, T. M.

    1999-01-01

    The melt-dilute treatment technology is being developed to facilitate the ultimate disposition of highly enriched Al-Base DOE spent nuclear fuels in a geologic repository such as that proposed for Yucca Mountain. The melt-dilute process is a method of preparing DOE spent nuclear fuel for long term storage

  11. 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

  12. Preparation of hydrotalcite compounds using ultrasound irradiation to capture CO{sub 2}; Preparacion de compuestos tipo hidrotalcita utilizando irradiacion de ultrasonido para la captura de CO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, J.A.J.; Paredes, S.P.; Valenzuela, M.A.; Hernandez, M.L. [Instituto Politecnico Nacional, ESIQIE, Mexico, D.F. (Mexico)]. E-mail: sparedesc@ipn.com.mx

    2009-09-15

    Al-Mg hydrotalcite compounds (HTC) were prepared using co-precipitation, sol-gel and reconstruction of the structure with ultrasound-assisted irradiation. The interlaminar components for each method were nitrate, acetylacetonate ethoxide and metavanadate, respectively. Optimization of the synthesis was performed using x-ray diffraction. The effect of the different parameters on synthesis was studied, including pH, time and ultrasound irradiation power. In addition, for the reconstruction method, temperature and calcination time were evaluated. For all methods, ultrasound-assisted methods were found to be more efficient and economical than conventional methods reported (autoclave). They also have the advantage of being able to control properties such as crystallinity, porosity and the specific surface, which significantly depends on the preparation method, irradiation time and type of interlaminar component. These methods are intended to synthesize interlaminar anionic materials that are very scarce in nature with better properties than traditional adsorbents used for the capture of CO{sub 2}. [Spanish] Se prepararon compuestos tipo hidrotalcita Al-Mg por los metodos de: coprecipitacion, sol gel y reconstruccion de la estructura asistidos por irradiacion de ultrasonido. Los componentes interlaminares para cada metodo fueron respectivamente: nitrato, etoxido-acetilacetonato y metavanadato. La optimizacion de la sintesis, se efectuo mediante difraccion de rayos-X. Se estudio el efecto de diversos parametros en la sintesis: pH, tiempo y potencia de irradiacion de ultrasonido, ademas, para el metodo de reconstruccion se evaluaron la temperatura y el tiempo de calcinacion. En todos los casos se encontro que el empleo de metodos asistidos por ultrasonido resultan ser mas eficientes y economicos que los metodos convencionales reportados (autoclave), ademas tienen la ventaja, de poder controlar propiedades tales como: la cristalinidad, la porosidad y la superficie

  13. Sample Preparations Used in Biomedical Research and Training at the Special Training Division of the Oak Ridge Institute of Nuclear Studies; Methodes de Preparation d'Echantillons Employees dans la Recherche et la Formation Biologiques et Medicales a la Division de Formation Speciale de l'Institut d'Etudes Nucleaires d'Oak Ridge; Prigotovlenie obraztsov dlya biomeditsinskikh issledovanij i dlya uchebnykh tselej v otdele spetsial'noj podgotovki okridzhskogo instituta yadernykh issledovanii; Metodos de Preparacion de Muestras Aplicados en las Investigaciones Biomedicas y en la Capacitacion Profesional de la Division de Formacion Especial del Instituto de Estudios Nucleares de Oak Ridge

    Energy Technology Data Exchange (ETDEWEB)

    Akers, L. K. [Oak Ridge Institute of Nuclear Studies, Oak Ridge, TN (United States)

    1965-10-15

    mixtes. Les mesures sont faites a l'aide d'une serie de compteurs a grilles Fairstein-Frisch relies a un analyseur a 512 canaux pour l'enregistrement simultane de plusieurs spectres. On utilise en outre des detecteurs a semi-conducteurs. L'auteur compare les donnees fournies par ces derniers aux resultats obtenus a l'aide de detecteurs a grilles. (author) [Spanish] En el desarrollo de los programas de investigacion y de capacitacion profesional de la Division de Formacion Especial se utiliza una amplia variedad de metodos de preparacion de muestras, que abarcan desde el empleo de sencillos portafuentes a base de materiales tales como metal, cartulina y plasticos hasta el de dispositivos de precipitacion que utilizan soportes de acero inoxidable y fibra de vidrio y portafuentes especiales para el recuento por centelleo laquido. Admas de estas tecnicas, se han elaborado diversos procedimientos de interes especial para la resolucion de problemas biomedicos. Uno de los mas importantes consiste en el empleo de una sintesis catalitica del benceno que se ha perfeccionado hasta el punto de que se obtiene un rendimiento global superior al 90%. Esta sintesis puede aplicarse a los compuestos de carbono de interes para los experimentos con indicadores de baja actividad y problemas de determinacion de edades. Dado que la sintesis entrana la produccion de anhidrido carbonico en una fase y la hidratacion de carburo metalico en otra, puede utilizarse ya sea para medir {sup 14}Co o {sup 3}H o ambos en experimentos con marcacion doble. Se realiza una labor considerable en la esfera del analisis por activacion de sustancias biologicas, particularmente en la ejecucion de los programas radioecologicos de la division. Se describen tecnicas especiales para la preparacion de estas sustancias destinadas al analisis por activacion y otras operaciones radioquimicas. Dado que sigue siendo dificil la cuestion de la resolucion en la espectroscopia alfa, el grupo da estudios oceanograficos y

  14. Isotope dilution analysis of environmental samples

    International Nuclear Information System (INIS)

    Tolgyessy, J.; Lesny, J.; Korenova, Z.; Klas, J.; Klehr, E.H.

    1986-01-01

    Isotope dilution analysis has been used for the determination of several trace elements - especially metals - in a variety of environmental samples, including aerosols, water, soils, biological materials and geological materials. Variations of the basic concept include classical IDA, substoichiometric IDA, and more recently, sub-superequivalence IDA. Each variation has its advantages and limitations. A periodic chart has been used to identify those elements which have been measured in environmental samples using one or more of these methods. (author)

  15. A novel reversed-phase HPLC method for the determination of urinary creatinine by pre-column derivatization with ethyl chloroformate: comparative studies with the standard Jaffé and isotope-dilution mass spectrometric assays.

    Science.gov (United States)

    Leung, Elvis M K; Chan, Wan

    2014-02-01

    Creatinine is an important biomarker for renal function diagnosis and normalizing variations in urinary drug/metabolites concentration. Quantification of creatinine in biological fluids such as urine and plasma is important for clinical diagnosis as well as in biomonitoring programs and urinary metabolomics/metabonomics research. Current methods for creatinine determination either are nonselective or involve the use of expensive mass spectrometers. In this paper, a novel reversed-phase high-performance liquid chromatographic (HPLC) method for the determination of creatinine of high hydrophilicity by pre-column derivatization with ethyl chloroformate is presented. N-Ethyloxycarbonylation of creatinine significantly enhanced the hydrophobicity of creatinine, facilitating its chromatographic retention as well as quantification by HPLC. Factors governing the derivatization reaction were studied and optimized. The developed method was validated and applied for the determination of creatinine in rat urine samples. Comparative studies with isotope-dilution mass spectrometric method revealed that the two methods do not yield systematic differences in creatinine concentrations, indicating the HPLC method is suitable for the determination of creatinine in urine samples.

  16. Interlaboratory comparison of agar dilution and Etest methods for determining the MICs of antibiotics used in management of Neisseria meningitidis infections

    NARCIS (Netherlands)

    Vázquez, Julio A.; Arreaza, Luisa; Block, Colin; Ehrhard, Ingrid; Gray, Stephen J.; Heuberger, Sigrid; Hoffmann, Steen; Kriz, Paula; Nicolas, Pierre; Olcen, Per; Skoczynska, Anna; Spanjaard, Lodewijk; Stefanelli, Paola; Taha, Muhamed-Kheir; Tzanakaki, Georgina

    2003-01-01

    Previous studies have shown that there is considerable variation in the methods and media used to determine the susceptibility of Neisseria meningitidis to antimicrobial agents in different countries. In this study, national and regional reference laboratories used a standardized methodology to

  17. Dilution and slow injection reduces the incidence of rocuronium-induced withdrawal movements in children

    OpenAIRE

    Shin, Young Hee; Kim, Chung Su; Lee, Jong-Hwan; Sim, Woo Seog; Ko, Justin Sangwook; Cho, Hyun Sung; Jeong, Hui Yeon; Lee, Hye Won; Kim, Sang Hyun

    2011-01-01

    Background The aim of this study was to evaluate whether slow injection of diluted rocuronium could reduce rocuronium-induced withdrawal movements effectively in children. Methods After loss of consciousness, rocuronium 0.6 mg/kg was administered into 171 children according to the pre-assigned groups as follows: Group CF, injection of non-diluted rocuronium over 5 seconds; Group CS, injection of non-diluted rocuronium over 1 minute; Group DF, injection of diluted rocuronium (10 times) over 5 ...

  18. Paradigms in isotope dilution mass spectrometry for elemental speciation analysis

    International Nuclear Information System (INIS)

    Meija, Juris; Mester, Zoltan

    2008-01-01

    Isotope dilution mass spectrometry currently stands out as the method providing results with unchallenged precision and accuracy in elemental speciation. However, recent history of isotope dilution mass spectrometry has shown that the extent to which this primary ratio measurement method can deliver accurate results is still subject of active research. In this review, we will summarize the fundamental prerequisites behind isotope dilution mass spectrometry and discuss their practical limits of validity and effects on the accuracy of the obtained results. This review is not to be viewed as a critique of isotope dilution; rather its purpose is to highlight the lesser studied aspects that will ensure and elevate current supremacy of the results obtained from this method

  19. Influence of extragent dilution upon light rare earths separation

    International Nuclear Information System (INIS)

    Korpusova, R.D.; Smirnova, N.N.

    1978-01-01

    The effect of diluting the extragent on separation of REE in the presence of 6 g-equiv. of LiNO 3 has been studied. For experiments use was made of TBP diluted with kerosene or butylbenzene (40,50,70 vol.%). The separation coefficients have been determined under conditions of saturation. The content of trace amounts of the components has been determined by the weight method; the content of macroimpurities - by the radiometric method. It has been established that the coefficient of Ce-La, Pr-La separation is not affected by the dilution of the extragent. The only exception is the Pr 142 -La pair; in the presence of trace amounts of better extracted element and two-fold dilution the separation coefficient increases almost by 150%. For the Pr-Ce pair the effect of dilution is better noticeable in that case when more extracted element is present in trace amounts. However, a comparison of the effect of dilution on separation coefficients of all REE pairs under study has shown that this effect is the strongest for the samarium-neodymium pair. The data obtained allow an assumption to be made that kerosene, as a diluent, affects the steric factor and coordination. Therefore, upon dilution the coefficient of the samarium-neodymium pair separation is affected most of all

  20. Dilute chemical decontamination program review

    International Nuclear Information System (INIS)

    Anstine, L.D.; Blomgren, J.C.; Pettit, P.J.

    1980-01-01

    The objective of the Dilute Chemical Decontamination Program is to develop and evaluate a process which utilizes reagents in dilute concentrations for the decontamination of BWR primary systems and for the maintenance of dose rates on the out-of-core surfaces at acceptable levels. A discussion is presented of the process concept, solvent development, advantages and disadvantages of reagent systems, and VNC loop tests. Based on the work completed to date it is concluded that (1) rapid decontamination of BWRs using dilute reagents is feasible; (2) reasonable reagent conditions for rapid chemical decontamination are: 0.01M oxalic acid + 0.005M citric acid, pH3.0, 90/degree/C, 0.5 to 1.0 ppm dissolved oxygen; (3) control of dissolved oxygen concentration is important, since high levels suppress the rate of decontamination and low levels allow precipitation of ferrous oxalate. 4 refs

  1. Development and method of use of a mass spectrometric isotope dilution analysis within the use of negative thermoionisation for determination of boron traces

    International Nuclear Information System (INIS)

    Zeininger, H.

    1984-01-01

    A mass spectrometric trace boron determination using negative thermionisation was developed. It is based on the determination of the ratio of BO 2 - isotopes ( 10 B and 11 B). A high stability and a constant intensity at a given temperature of the BO 2 - ion currents allow for a computer controlled measurement with a programmed heating. The reproducibility lies at around 0,004-0,08%. The boron determination using Mels potentiometry with a BF 4 - -ion selective electrode was used as an analytical comparison method. The MS-IDA was first used on metal samples, such as Al, Zr, and steel. Later on the boron in reagents, biological material (milk powder, spinach, water plants) and water were determined. For this material-dependent hydrolysation and separation procedures were worked out. The MS-IDA in comparison to all other analytical methods used by other collaborators offers the greatest accuracy. (RB) [de

  2. Isotope dilution mass spectrometry as the primary method of measurement for the amount of matter. Application to cadmium determination in biological materials and comparison with instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Munoz, Luis; Gras, Nuri; Quejido, Alberto; Ferrada, Carlos

    2001-01-01

    A primary method of measurement as defined by the Consultative Committee on the Quantity of Matter (Comite Consultatif pour la Quantite de Matiere, CCQM) of the International Bureau of Weights and Measurements (Bureau International des Poids et Mesures, BIPM), is one whose measurement process is perfectly known, has valid theoretical foundations and is fully described and answers to an equation that relates what is measured with what is intended to be measured without any significant empirical correction factors. It is also a method that has insignificant systematic errors, where only magnitudes from the International System of Units (SI) are used and where, preferably, the uncertainties are small ones. They are, therefore, procedures that do not need instrumental calibration. The absolute methods of measurement allow a chain of traceability to be formed between the result obtained and the magnitude of the SI assigned to what is measured. So the results are said to be traceable to the SI. One of the methods that meets these requirements and is recognized as the primary method by the CCQM is Isotope Dilution Mass Spectrometry (IDMS). Through a project of Technical Cooperation with the International Atomic Energy Agency in the area of Chemical Metrology, the CCHEN obtained training in CIEMAT, Spain, in IDMS and its applications to the analysis of biological samples. This work describes the first experience carried out entirely in Chilean laboratories, applying IDMS to the determination of cadmium in the biological reference materials Oyster Tissue 15566-A from the NIST, United States, Dogfish Liver, DOLT-2 from the NRC-CNRC, Canada and Poplar Leaves GBW07604 from the NRCC, China. The samples were traced with an isotope enriched spike 111 Cd and then shaken to obtain the isotopic exchange. Once dissolved, the isotopic relationship 111 Cd/ 114 Cd was determined in the samples using mass spectrometry with plasma source. These results were compared with those obtained

  3. N-2-fixation ability of three main soybean cultivars in symbiosis with bradyrhizobium japonicum using N-15 isotope dilution method in Iran

    International Nuclear Information System (INIS)

    Piervali-Bieranvand, N.; Saleh-Rastin, N.; Mousavi-Shalmani, M. A.

    2006-01-01

    The present pot study was carried out for comparison of N 2 fixation ability for three main soybean cultivars in Iran i.,e. Sahar, Williams and Clark 63. The experiment was conducted under the proper growth chamber condition, with a randomized complete block design on a soil with no indigenous rhizobia and low nitrogen content. Each treatment was replicated four times. Each pot contained 3.5-kg air dried homogenized soil, and at the time of planting each seedling was inoculated with 1 ml of inoculum containing approximately 9 x 10 8 cells per ml. For quantifying the fixed nitrogen, using A- value (N-15) method, two solutions of N-15 enriched ammonium sulfate containing 9.616 and 2.086% N-15 atom excess were applied in amount of 6.67 and 33.33 mg/kg N at the stage V2 for the fixing, and for the stages V2, R2 and R5 as reference pots. During 4 months of growth, the plants were irrigated with distilled water to maintain the soil moisture approximately 0.8 of the field capacity. The plants were harvested at the plant developmental stage reproductive 6 (R6) and a number of growth parameters were measured. According to the results, Sahar cultivar which is more lateness, showed a higher results in the most measured characteristics, including nitrogen derived from air, shoot dry matter, nodule dry matter and the whole dry matter of plant, significantly. All the three cultivars could supply more than 90 % of nitrogen demand through symbiosis. The cultivars were different significantly in amount of nitrogen derived from air, despite of the percent of nitrogen derived from air

  4. Dilution Refrigeration of Multi-Ton Cold Masses

    CERN Document Server

    Wikus, P; CERN. Geneva

    2007-01-01

    Dilution refrigeration is the only means to provide continuous cooling at temperatures below 250 mK. Future experiments featuring multi-ton cold masses require a new generation of dilution refrigeration systems, capable of providing a heat sink below 10 mK at cooling powers which exceed the performance of present systems considerably. This thesis presents some advances towards dilution refrigeration of multi-ton masses in this temperature range. A new method using numerical simulation to predict the cooling power of a dilution refrigerator of a given design has been developed in the framework of this thesis project. This method does not only allow to take into account the differences between an actual and an ideal continuous heat exchanger, but also to quantify the impact of an additional heat load on an intermediate section of the dilute stream. In addition, transient behavior can be simulated. The numerical model has been experimentally verified with a dilution refrigeration system which has been designed, ...

  5. Synthesis of trans-4,5-epoxy-(E)-2-decenal and its deuterated analog used for the development of a sensitive and selective quantification method based on isotope dilution assay with negative chemical ionization.

    Science.gov (United States)

    Lin, J; Fay, L B; Welti, D H; Blank, I

    1999-10-01

    The volatile compound trans-4,5-epoxy-(E)-2-decenal (1) was synthesized in two steps with good overall yields. The newly developed method is based on trans-epoxidation of (E)-2-octenal with alkaline hydrogen peroxide followed by a Wittig-type chain elongation with the ylide formylmethylene triphenylphosphorane. For the synthesis of [4,5-2H2]-trans-4,5-epoxy-(E)-2-decenal (d-1), [2,3-2H2]-(E)-2-octenal was prepared by reduction of 2-octyn-1-ol with lithium aluminum deuteride and subsequent oxidation of [2,3-2H2]-(E)-2-octen-1-ol with manganese oxide. Compound d1 was used as internal standard for the quantification of 1 by isotope dilution assay. Among various mass spectrometry (MS) ionization techniques tested, negative chemical ionization with ammonia as reagent gas gave best results with respect to both sensitivity and selectivity. The detection limit was found to be at about 1 pg of the analyte introduced into the gas chromatography-MS system.

  6. Primary system boron dilution analysis

    International Nuclear Information System (INIS)

    Crump, R.J.; Naretto, C.J.; Borgen, R.A.; Rockhold, H.C.

    1978-01-01

    The results are presented for an analysis conducted to determine the potential paths through which nonborated water or water with insufficient boron concentration might enter the LOFT primary coolant piping system or reactor vessel to cause dilution of the borated primary coolant water. No attempt was made in the course of this analysis to identify possible design modifications nor to suggest changes in administrative procedures or controls

  7. Cryogen-free dilution refrigerators

    International Nuclear Information System (INIS)

    Uhlig, K

    2012-01-01

    We review briefly our first cryogen-free dilution refrigerator (CF-DR) which was precooled by a GM cryocooler. We then show how today's dry DRs with pulse tube precooling have developed. A few examples of commercial DRs are explained and noteworthy features pointed out. Thereby we describe the general advantages of cryogen-free DRs, but also show where improvements are still desirable. At present, our dry DR has a base temperature of 10 mK and a cooling capacity of 700 μW at a mixing chamber temperature of 100 mK. In our cryostat, in most recent work, an additional refrigeration loop was added to the dilution circuit. This 4 He circuit has a lowest temperature of about 1 K and a refrigeration capacity of up to 100 mW at temperatures slightly above 1 K; the dilution circuit and the 4 He circuit can be run separately or together. The purpose of this additional loop is to increase the cooling capacity for experiments where the cooling power of the still of the DR is not sufficient to cool cold amplifiers and cables, e.g. in studies on superconducting quantum circuits or astrophysical applications.

  8. Cryogen-free dilution refrigerators

    Science.gov (United States)

    Uhlig, K.

    2012-12-01

    We review briefly our first cryogen-free dilution refrigerator (CF-DR) which was precooled by a GM cryocooler. We then show how today's dry DRs with pulse tube precooling have developed. A few examples of commercial DRs are explained and noteworthy features pointed out. Thereby we describe the general advantages of cryogen-free DRs, but also show where improvements are still desirable. At present, our dry DR has a base temperature of 10 mK and a cooling capacity of 700 μW at a mixing chamber temperature of 100 mK. In our cryostat, in most recent work, an additional refrigeration loop was added to the dilution circuit. This 4He circuit has a lowest temperature of about 1 K and a refrigeration capacity of up to 100 mW at temperatures slightly above 1 K; the dilution circuit and the 4He circuit can be run separately or together. The purpose of this additional loop is to increase the cooling capacity for experiments where the cooling power of the still of the DR is not sufficient to cool cold amplifiers and cables, e.g. in studies on superconducting quantum circuits or astrophysical applications.

  9. Development of an accurate, sensitive, and robust isotope dilution laser ablation ICP-MS method for simultaneous multi-element analysis (chlorine, sulfur, and heavy metals) in coal samples

    International Nuclear Information System (INIS)

    Boulyga, Sergei F.; Heilmann, Jens; Heumann, Klaus G.; Prohaska, Thomas

    2007-01-01

    A method for the direct multi-element determination of Cl, S, Hg, Pb, Cd, U, Br, Cr, Cu, Fe, and Zn in powdered coal samples has been developed by applying inductively coupled plasma isotope dilution mass spectrometry (ICP-IDMS) with laser-assisted introduction into the plasma. A sector-field ICP-MS with a mass resolution of 4,000 and a high-ablation rate laser ablation system provided significantly better sensitivity, detection limits, and accuracy compared to a conventional laser ablation system coupled with a quadrupole ICP-MS. The sensitivity ranges from about 590 cps for 35 Cl + to more than 6 x 10 5 cps for 238 U + for 1 μg of trace element per gram of coal sample. Detection limits vary from 450 ng g -1 for chlorine and 18 ng g -1 for sulfur to 9.5 pg g -1 for mercury and 0.3 pg g -1 for uranium. Analyses of minor and trace elements in four certified reference materials (BCR-180 Gas Coal, BCR-331 Steam Coal, SRM 1632c Trace Elements in Coal, SRM 1635 Trace Elements in Coal) yielded good agreement of usually not more than 5% deviation from the certified values and precisions of less than 10% relative standard deviation for most elements. Higher relative standard deviations were found for particular elements such as Hg and Cd caused by inhomogeneities due to associations of these elements within micro-inclusions in coal which was demonstrated for Hg in SRM 1635, SRM 1632c, and another standard reference material (SRM 2682b, Sulfur and Mercury in Coal). The developed LA-ICP-IDMS method with its simple sample pretreatment opens the possibility for accurate, fast, and highly sensitive determinations of environmentally critical contaminants in coal as well as of trace impurities in similar sample materials like graphite powder and activated charcoal on a routine basis. (orig.)

  10. Development of an accurate, sensitive, and robust isotope dilution laser ablation ICP-MS method for simultaneous multi-element analysis (chlorine, sulfur, and heavy metals) in coal samples.

    Science.gov (United States)

    Boulyga, Sergei F; Heilmann, Jens; Prohaska, Thomas; Heumann, Klaus G

    2007-10-01

    A method for the direct multi-element determination of Cl, S, Hg, Pb, Cd, U, Br, Cr, Cu, Fe, and Zn in powdered coal samples has been developed by applying inductively coupled plasma isotope dilution mass spectrometry (ICP-IDMS) with laser-assisted introduction into the plasma. A sector-field ICP-MS with a mass resolution of 4,000 and a high-ablation rate laser ablation system provided significantly better sensitivity, detection limits, and accuracy compared to a conventional laser ablation system coupled with a quadrupole ICP-MS. The sensitivity ranges from about 590 cps for (35)Cl+ to more than 6 x 10(5) cps for (238)U+ for 1 microg of trace element per gram of coal sample. Detection limits vary from 450 ng g(-1) for chlorine and 18 ng g(-1) for sulfur to 9.5 pg g(-1) for mercury and 0.3 pg g(-1) for uranium. Analyses of minor and trace elements in four certified reference materials (BCR-180 Gas Coal, BCR-331 Steam Coal, SRM 1632c Trace Elements in Coal, SRM 1635 Trace Elements in Coal) yielded good agreement of usually not more than 5% deviation from the certified values and precisions of less than 10% relative standard deviation for most elements. Higher relative standard deviations were found for particular elements such as Hg and Cd caused by inhomogeneities due to associations of these elements within micro-inclusions in coal which was demonstrated for Hg in SRM 1635, SRM 1632c, and another standard reference material (SRM 2682b, Sulfur and Mercury in Coal). The developed LA-ICP-IDMS method with its simple sample pretreatment opens the possibility for accurate, fast, and highly sensitive determinations of environmentally critical contaminants in coal as well as of trace impurities in similar sample materials like graphite powder and activated charcoal on a routine basis.

  11. A miniaturized plastic dilution refrigerator

    International Nuclear Information System (INIS)

    Bindilatti, V.; Oliveira, N.F.Jr.; Martin, R.V.; Frossati, G.

    1996-01-01

    We have built and tested a miniaturized dilution refrigerator, completely contained (still, heat exchanger and mixing chamber) inside a plastic (PVC) tube of 10 mm diameter and 170 mm length. With a 25 cm 2 CuNi heat exchanger, it reached temperatures below 50 mK, for circulation rates below 70 μmol/s. The cooling power at 100 mK and 63 μmol/s was 45 μW. The experimental space could accommodate samples up to 6 mm in diameter. (author)

  12. The Statistical Mechanics of Dilute, Disordered Systems

    Science.gov (United States)

    Blackburn, Roger Michael

    Available from UMI in association with The British Library. Requires signed TDF. A graph partitioning problem with variable inter -partition costs is studied by exploiting its mapping on to the Ashkin-Teller spin glass. The cavity method is used to derive the TAP equations and free energy for both extensively connected and dilute systems. Unlike Ising and Potts spin glasses, the self-consistent equation for the distribution of effective fields does not have a solution solely made up of delta functions. Numerical integration is used to find the stable solution, from which the ground state energy is calculated. Simulated annealing is used to test the results. The retrieving activity distribution for networks of boolean functions trained as associative memories for optimal capacity is derived. For infinite networks, outputs are shown to be frozen, in contrast to dilute asymmetric networks trained with the Hebb rule. For finite networks, a steady leaking to the non-retrieving attractor is demonstrated. Simulations of quenched networks are reported which show a departure from this picture: some configurations remain frozen for all time, while others follow cycles of small periods. An estimate of the critical capacity from the simulations is found to be in broad agreement with recent analytical results. The existing theory is extended to include noise on recall, and the behaviour is found to be robust to noise up to order 1/c^2 for networks with connectivity c.

  13. Quantifying the dilution effect for models in ecological epidemiology.

    Science.gov (United States)

    Roberts, M G; Heesterbeek, J A P

    2018-03-01

    The dilution effect , where an increase in biodiversity results in a reduction in the prevalence of an infectious disease, has been the subject of speculation and controversy. Conversely, an amplification effect occurs when increased biodiversity is related to an increase in prevalence. We explore the conditions under which these effects arise, using multi species compartmental models that integrate ecological and epidemiological interactions. We introduce three potential metrics for quantifying dilution and amplification, one based on infection prevalence in a focal host species, one based on the size of the infected subpopulation of that species and one based on the basic reproduction number. We introduce our approach in the simplest epidemiological setting with two species, and show that the existence and strength of a dilution effect is influenced strongly by the choices made to describe the system and the metric used to gauge the effect. We show that our method can be generalized to any number of species and to more complicated ecological and epidemiological dynamics. Our method allows a rigorous analysis of ecological systems where dilution effects have been postulated, and contributes to future progress in understanding the phenomenon of dilution in the context of infectious disease dynamics and infection risk. © 2018 The Author(s).

  14. A Study on the Stability of Diluted Bee Venom Solution

    Directory of Open Access Journals (Sweden)

    Mi-Suk Kang

    2003-06-01

    Full Text Available Objective : The purpose of this study was to investigate the stability of bee venom according to the keeping method and period. Method : The author observed microbial contamination of bee venom in nutrient agar, broth, YPD agar and YPD media and antibacterial activity for S. aureus, E. coli manufactured 12, 6 and 3 months ago as the two type of room temperature and 4℃ cold storage. Result : 1. 1:3,000 and 1:4,000 diluted bee venom solution did not show microbial contamination both room temperature and cold storage within twelve months. 2. There was antibacterial activity of diluted bee venom for S. aureus in cold storage within twelve months and there was no antibacterial activity of diluted bee venom for S. aureus in twelve months, room temperature storage. 3. We could not observe the zone of inhibition around paper disc of all for E.coli. in 1:3,000, 1:30,000 and 1:3,000,000 diluted bee venom solution, respectively. According to results, we expect that diluted bee venom solution is stable both cold and room temperature storage within twelve months.

  15. Guideline on Isotope Dilution Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Gaffney, Amy [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-05-19

    Isotope dilution mass spectrometry is used to determine the concentration of an element of interest in a bulk sample. It is a destructive analysis technique that is applicable to a wide range of analytes and bulk sample types. With this method, a known amount of a rare isotope, or ‘spike’, of the element of interest is added to a known amount of sample. The element of interest is chemically purified from the bulk sample, the isotope ratio of the spiked sample is measured by mass spectrometry, and the concentration of the element of interest is calculated from this result. This method is widely used, although a mass spectrometer required for this analysis may be fairly expensive.

  16. Multi-element isotope dilution analyses using ICP-MS

    International Nuclear Information System (INIS)

    Volpe, A.M.

    1996-01-01

    Presently, 37 elements ranging from light (Li,B) through transition metals, noble, rare earth and heavy elements, to actinides and transuranics (Pu, Am, Cm) are measured by isotope dilution at Lawrence Livermore National Laboratory. Projects range from geological and hydrological to biological. The research goal is to measure accurately many elements present in diverse matrices at trace (ppb) levels using isotope dilution methods. Major advantages of isotope dilution methods are accuracy, elimination of ion intensity calibration, and quantitation for samples that require chemical separation. Accuracy depends on tracer isotope calibration, tracer-sample isotopic equilibration, and appropriate background, isobaric and mass bias corrections. Propagation of isotope ratio error due to improper tracer isotope addition is a major concern with multi-element analyses when abundances vary widely. 11 refs., 3 figs

  17. Studies on the dilution behaviour of effluent discharged into the CCW channel at KGS

    International Nuclear Information System (INIS)

    Sivasubramanian, K.; Srinivasan, S.; Ponraju, D.; Meenakshisundaram, V.; Munusamy, N.

    2003-01-01

    The dilution behaviour of the liquid effluent discharged into condenser cooling water channel of Kaiga Power Plant has been studied using salt addition and dye addition methods. Dilution factors determined experimentally showed that the discharged liquid effluent gets thoroughly mixed with stream of water at the weir and further diluted in the down stream. This paper describes both salt and dye addition methods for determining the dilution factor. The velocity of the stream at various locations were measured and compared with reported values. The selection of representative sampling point for routine analysis of water was identified from this experiment. (author)

  18. Buffer erosion in dilute groundwater

    International Nuclear Information System (INIS)

    Schatz, T.; Kanerva, N.; Martikainen, J.; Sane, P.; Olin, M.; Seppaelae, A.; Koskinen, K.

    2013-08-01

    One scenario of interest for repository safety assessment involves the loss of bentonite buffer material in contact with dilute groundwater flowing through a transmissive fracture interface. In order to examine the extrusion/erosion behavior of bentonite buffer material under such circumstances, a series of experiments were performed in a flow-through, 1 mm aperture, artificial fracture system. These experiments covered a range of solution chemistry (salt concentration and composition), material composition (sodium montmorillonite and admixtures with calcium montmorillonite), and flow velocity conditions. No erosion was observed for sodium montmorillonite against solution compositions from 0.5 g/L to 10 g/L NaCl. No erosion was observed for 50/50 calcium/sodium montmorillonite against 0.5 g/L NaCl. Erosion was observed for both sodium montmorillonite and 50/50 calcium/sodium montmorillonite against solution compositions ≤ 0.25 g/L NaCl. The calculated erosion rates for the tests with the highest levels of measured erosion, i.e., the tests run under the most dilute conditions (ionic strength (IS) < ∼1 mM), were well-correlated to flow velocity, whereas the calculated erosion rates for the tests with lower levels of measured erosion, i.e., the tests run under somewhat less dilute conditions (∼1 mM < IS < ∼4 mM), were not similarly correlated indicating that material and solution composition can significantly affect erosion rates. In every experiment, both erosive and non-erosive, emplaced buffer material extruded into the fracture and was observed to be impermeable to water flowing in the fracture effectively forming an extended diffusive barrier around the intersecting fracture/buffer interface. Additionally, a model which was developed previously to predict the rate of erosion of bentonite buffer material in low ionic strength water in rock fracture environments was applied to three different cases: sodium montmorillonite expansion in a vertical tube, a

  19. Development of an accurate, sensitive, and robust isotope dilution laser ablation ICP-MS method for simultaneous multi-element analysis (chlorine, sulfur, and heavy metals) in coal samples

    Energy Technology Data Exchange (ETDEWEB)

    Boulyga, Sergei F. [University of Natural Resources and Applied Life Sciences, Department of Chemistry, Division of Analytical Chemistry-VIRIS Laboratory, Vienna (Austria); Johannes Gutenberg-University, Institute of Inorganic Chemistry and Analytical Chemistry, Mainz (Germany); Heilmann, Jens; Heumann, Klaus G. [Johannes Gutenberg-University, Institute of Inorganic Chemistry and Analytical Chemistry, Mainz (Germany); Prohaska, Thomas [University of Natural Resources and Applied Life Sciences, Department of Chemistry, Division of Analytical Chemistry-VIRIS Laboratory, Vienna (Austria)

    2007-10-15

    A method for the direct multi-element determination of Cl, S, Hg, Pb, Cd, U, Br, Cr, Cu, Fe, and Zn in powdered coal samples has been developed by applying inductively coupled plasma isotope dilution mass spectrometry (ICP-IDMS) with laser-assisted introduction into the plasma. A sector-field ICP-MS with a mass resolution of 4,000 and a high-ablation rate laser ablation system provided significantly better sensitivity, detection limits, and accuracy compared to a conventional laser ablation system coupled with a quadrupole ICP-MS. The sensitivity ranges from about 590 cps for {sup 35}Cl{sup +} to more than 6 x 10{sup 5} cps for {sup 238}U{sup +} for 1 {mu}g of trace element per gram of coal sample. Detection limits vary from 450 ng g{sup -1} for chlorine and 18 ng g{sup -1} for sulfur to 9.5 pg g{sup -1} for mercury and 0.3 pg g{sup -1} for uranium. Analyses of minor and trace elements in four certified reference materials (BCR-180 Gas Coal, BCR-331 Steam Coal, SRM 1632c Trace Elements in Coal, SRM 1635 Trace Elements in Coal) yielded good agreement of usually not more than 5% deviation from the certified values and precisions of less than 10% relative standard deviation for most elements. Higher relative standard deviations were found for particular elements such as Hg and Cd caused by inhomogeneities due to associations of these elements within micro-inclusions in coal which was demonstrated for Hg in SRM 1635, SRM 1632c, and another standard reference material (SRM 2682b, Sulfur and Mercury in Coal). The developed LA-ICP-IDMS method with its simple sample pretreatment opens the possibility for accurate, fast, and highly sensitive determinations of environmentally critical contaminants in coal as well as of trace impurities in similar sample materials like graphite powder and activated charcoal on a routine basis. (orig.)

  20. Desynchronization in diluted neural networks

    International Nuclear Information System (INIS)

    Zillmer, Ruediger; Livi, Roberto; Politi, Antonio; Torcini, Alessandro

    2006-01-01

    The dynamical behavior of a weakly diluted fully inhibitory network of pulse-coupled spiking neurons is investigated. Upon increasing the coupling strength, a transition from regular to stochasticlike regime is observed. In the weak-coupling phase, a periodic dynamics is rapidly approached, with all neurons firing with the same rate and mutually phase locked. The strong-coupling phase is characterized by an irregular pattern, even though the maximum Lyapunov exponent is negative. The paradox is solved by drawing an analogy with the phenomenon of 'stable chaos', i.e., by observing that the stochasticlike behavior is 'limited' to an exponentially long (with the system size) transient. Remarkably, the transient dynamics turns out to be stationary

  1. A compact rotating dilution refrigerator

    Science.gov (United States)

    Fear, M. J.; Walmsley, P. M.; Chorlton, D. A.; Zmeev, D. E.; Gillott, S. J.; Sellers, M. C.; Richardson, P. P.; Agrawal, H.; Batey, G.; Golov, A. I.

    2013-10-01

    We describe the design and performance of a new rotating dilution refrigerator that will primarily be used for investigating the dynamics of quantized vortices in superfluid 4He. All equipment required to operate the refrigerator and perform experimental measurements is mounted on two synchronously driven, but mechanically decoupled, rotating carousels. The design allows for relative simplicity of operation and maintenance and occupies a minimal amount of space in the laboratory. Only two connections between the laboratory and rotating frames are required for the transmission of electrical power and helium gas recovery. Measurements on the stability of rotation show that rotation is smooth to around 10-3 rad s-1 up to angular velocities in excess of 2.5 rad s-1. The behavior of a high-Q mechanical resonator during rapid changes in rotation has also been investigated.

  2. Non‐diluted seawater enhances nasal ciliary beat frequency and wound repair speed compared to diluted seawater and normal saline

    Science.gov (United States)

    Bonnomet, Arnaud; Luczka, Emilie; Coraux, Christelle

    2016-01-01

    Background The regulation of mucociliary clearance is a key part of the defense mechanisms developed by the airway epithelium. If a high aggregate quality of evidence shows the clinical effectiveness of nasal irrigation, there is a lack of studies showing the intrinsic role of the different irrigation solutions allowing such results. This study investigated the impact of solutions with different pH and ionic compositions, eg, normal saline, non‐diluted seawater and diluted seawater, on nasal mucosa functional parameters. Methods For this randomized, controlled, blinded, in vitro study, we used airway epithelial cells obtained from 13 nasal polyps explants to measure ciliary beat frequency (CBF) and epithelial wound repair speed (WRS) in response to 3 isotonic nasal irrigation solutions: (1) normal saline 0.9%; (2) non‐diluted seawater (Physiomer®); and (3) 30% diluted seawater (Stérimar). The results were compared to control (cell culture medium). Results Non‐diluted seawater enhanced the CBF and the WRS when compared to diluted seawater and to normal saline. When compared to the control, it significantly enhanced CBF and slightly, though nonsignificantly, improved the WRS. Interestingly, normal saline markedly reduced the number of epithelial cells and ciliated cells when compared to the control condition. Conclusion Our results suggest that the physicochemical features of the nasal wash solution is important because it determines the optimal conditions to enhance CBF and epithelial WRS thus preserving the respiratory mucosa in pathological conditions. Non‐diluted seawater obtains the best results on CBF and WRS vs normal saline showing a deleterious effect on epithelial cell function. PMID:27101776

  3. Dynamics of dilute disordered models: A solvable case

    International Nuclear Information System (INIS)

    Semerjian, Guilhem; Cugliandolo, Leticia F.

    2003-09-01

    We study the dynamics of a dilute spherical model with two body interactions and random exchanges. We analyze the Langevin equations and we introduce a functional variational method to study generic dilute disordered models. A crossover temperature replaces the dynamic transition of the fully-connected limit. There are two asymptotic regimes, one determined by the central band of the spectral density of the interactions and a slower one determined by localized configurations on sites with high connectivity. We confront the behavior of this model to the one of real glasses. (author)

  4. Alpha-clustering in dilute nucleonic sea

    International Nuclear Information System (INIS)

    Tohsaki, Akihiro

    1999-01-01

    α-clusters are expected to come out here and there in nucleonic sea owing to energetic benefit as its density is diluted. We propose a precise treatment to elucidate α-clusterized process in nucleonic sea after the breakdown of the uniformness. In order to do this, an infinite number of nucleons are considered by taking account of both the Pauli exclusion principle and effective internucleon forces. This method is called a microscopic approach, which has been successful in an α-cluster structure in light nuclei. In particular, we shed light on overcoming difficulties in a static model within the microscopic framework. This improvement is verified by using the empirical value in Weizaecker's mass formula. (author)

  5. Water Metabolism of Walruses by Isotope Dilution

    DEFF Research Database (Denmark)

    Acquarone, M.; Born, E. W.; Chwalibog, A.

    was sampled via an epidural catheter, at regular intervals, for up to seven hours after the initial enrichment to assess isotope equilibration in the body water pools. Five individuals returned to the haul-out after feeding trips of varying duration (158±86 hr, 44-287 hr) where they were immobilized again......In August 2000, the hydrogen isotope dilution method was used on 7 adult male Atlantic walruses (Odobenus rosmarus rosmarus) (weight: 1197±148 kg, mean±SD, range 1013-1508 kg) at a terrestrial haul-out in Northeastern Greenland to determine their body water pool sizes and body water turnover rates....... During immobilization by use of etorphine HCl (reversed with diprenorphine HCl), a first blood sample was taken to measure background isotope levels. The animals were then enriched with deuterium oxide by infusion into the epidural vein. During recovery, while the animals were still on the beach, blood...

  6. Cost effectiveness of dilute chemical decontamination

    International Nuclear Information System (INIS)

    Le Surf, J.E.; Weyman, G.D.

    1983-01-01

    The origin and basic principles of the dilute chemical decontamination (DCD) concept are described and illustrated by reference to the CAN-DECON process. The estimated dose savings from the actual application of the process at several reactors are presented and discussed. Two methods of performing a cost/benefit appraisal are described and discussed. This methodology requires more study by the nuclear industry, including collection by station staff of relevant data on which future cost/benefit appraisals may be based. Finally, three illustrative cases are examinated to show the breakeven point and potential savings achievable by DCD with different initial radiation fields and different amounts of work to be done. The overall conclusion is that there are many situations in which DCD is desirable to reduce radiation exposure of workers, to save costs to the station, and to ease the performance of maintenance and repair work on reactor systems

  7. ERM booster vaccination of Rainbow trout using diluted bacterin

    DEFF Research Database (Denmark)

    Schmidt, Jacob Günther; Henriksen, Niels H.; Buchmann, Kurt

    2016-01-01

    under laboratory conditions extend the protection period. The present field study investigated the applicability of the method under practical farming conditions (freshwater earth ponds supplied by stream water). Primary immersion vaccination of trout (3–4 g) for 30 s in Y. ruckeri bacterin (diluted 1......Enteric Red Mouth Disease ERM caused by Yersinia ruckeri infection is associated with morbidity and mortality in salmonid farming but immersion vaccination of fry may confer some protection for a number of months. Revaccination of rainbow trout, even by use of diluted ERM immersion vaccine, can......:10) in April 2015 was followed 3 months later (July 2015) by 1 h bathing of rainbow trout in bacterin (diluted 1:650 or 1:1700) in order to evaluate if this time saving vaccination methodology can improve immunity and protection. Trout were subjected in farms to natural Y. ruckeri exposure in June and July...

  8. Moderate Dilution of Copper Slag by Natural Gas

    Science.gov (United States)

    Zhang, Bao-jing; Zhang, Ting-an; Niu, Li-ping; Liu, Nan-song; Dou, Zhi-he; Li, Zhi-qiang

    2018-01-01

    To enable use of copper slag and extract the maximum value from the contained copper, an innovative method of reducing moderately diluted slag to smelt copper-containing antibacterial stainless steel is proposed. This work focused on moderate dilution of copper slag using natural gas. The thermodynamics of copper slag dilution and ternary phase diagrams of the slag system were calculated. The effects of blowing time, temperature, matte settling time, and calcium oxide addition were investigated. The optimum reaction conditions were identified to be blowing time of 20 min, reaction temperature of 1250°C, settling time of 60 min, CaO addition of 4% of mass of slag, natural gas flow rate of 80 mL/min, and outlet pressure of 0.1 MPa. Under these conditions, the Fe3O4 and copper contents of the residue were 7.36% and 0.50%, respectively.

  9. In vitro dilutions of thioridaxine with potential to enhance antibiotic ...

    African Journals Online (AJOL)

    Gram staining, catalase test and coagulase test were done on the resulting colonies to further confirm the strains as S. aureus. Antibiotic susceptibility test was done by agar disc diffusion method using sterile Mueller- Hinton agar plates before and after treatment with laboratory dilutions of thioridaxine. S. aureus strains 1, ...

  10. Time correlation functions and transport coefficients in a dilute superfluid

    International Nuclear Information System (INIS)

    Kirkpatrick, T.R.; Dorfman, J.R.

    1985-01-01

    Time correlation functions for the transport coefficients in the linear Landau-Khalatnikov equations are derived on the basis of a formal theory. These Green--Kubo expressions are then explicitly evaluated for a dilute superfluid and the resulting transport coefficiencts are shown to be identical to those obtained previously by using a distribution function method

  11. Actualización bibliográfica sobre el uso de preparaciones ricas en plaquetas en la cicatrización de heridas Updated review of the use of platelet rich preparations in wound healing

    Directory of Open Access Journals (Sweden)

    D.A. Mateo de Acosta Andino

    2010-09-01

    Full Text Available Las plaquetas poseen más de 20 factores de crecimiento en sus gránulos. Su secreción promueve la reparación de heridas. La cicatrización es un intrincado proceso en el cual intervienen no solo los factores plaquetarios proangiogénicos sino también factores antiangiogénicos. La preservación por congelación de las plaquetas empleada para su preservación, desestabiliza y activa la membrana plaquetaria alterando sus propiedades. En el campo del tratamiento de heridas recalcitrantes en pacientes debilitados o con enfermedades crónicas, el uso de preparaciones plaquetarias en forma de plasma fresco congelado, las preparaciones plaquetarias sonicadas, las preparaciones congeladas y deshidratadas y el uso de fragmentos de dermis alogénica, confiere efectos beneficiosos, logrando mejores tiempos de cierre en las heridas y menor alteración de la morfología de la cicatriz final. En el presente artículo, describiremos los estudios que han demostrado estos efectos, así como las encrucijadas actuales y los estudios que debemos esperar en un futuro no lejano.Platelets store more than 20 growth factors in their granules. Their secretion promotes wound healing and repair. The intricate wound healing process involves not only the angiogenic platelet factors but also de anti-angiogenic ones. The process of platelet preservation, such as freezing, disrupt the platelet membrane structure and their angiogenic properties causing platelet activation. In the field of wound healing and the management of recalcitrant wounds in debilitated and chronically ill patients, there have been several studies. These studies have focused on the use of the different platelet preparations such as fresh frozen plasma, frozen-dried platelet rich plasma, sonicated platelet rich plasma and the use of alogenic acelular dermis. Platelet preparations posses positive effects on wound healing with little alterations of the final scar tissue. In this article we will describe

  12. Dynamics of dilute polymer solutions

    International Nuclear Information System (INIS)

    Nicholson, L.K.; Higgins, J.S.

    1980-01-01

    Neutrons scattered by nuclei undergoing slow motion e.g. the internal motion within polymer chains, lose or gain very small amounts of energy. It is therefore the quasi-elastic region of the neutron scattering spectrum which is of interest and in particular the time correlation function (or intermediate scattering law S(Q,t)) which is ideally required to define the motion. The neutron spin echo spectrometer (IN11) at the ILL facilitates the measurement of very small energy changes (down to 10 neV) on scattering from a sample, by changing and keeping track of neutron beam polarization non-parallel to the magnetic guide-field (1). The resultant neutron beam polarization, when normalized against a standard (totally elastic) scatterer is directly proportional to the cosine Fourier Transform of the scattering law S(Q,ω), which is to say the time correlation function is measured directly. Dilute solutions of deuterated polystyrene (PSD) and deuterated polytetrahydrofuran (PTDF) in carbon disulphide, and of their hydrogeneous counterparts (PSH and PTHF respectively) in deuterated benzene were investigated in the range 0.027 A -1 -1 , at 30 0 C. (orig./FKS)

  13. Storm Sewage Dilution in Smaller Streams

    DEFF Research Database (Denmark)

    Larsen, Torben; Vestergaard, Kristian

    1987-01-01

    A numerical model has been used to show how dilution in smaller streams can be effected by unsteady hydraulic conditions caused by a storm sewage overflow.......A numerical model has been used to show how dilution in smaller streams can be effected by unsteady hydraulic conditions caused by a storm sewage overflow....

  14. Dissolution rates of unirradiated UO{sub 2}, UO{sub 2} doped with {sup 233}U, and spent fuel under normal atmospheric conditions and under reducing conditions using an isotope dilution method

    Energy Technology Data Exchange (ETDEWEB)

    Ollila, Kaija [VTT Processes, Helsinki (Finland); Albinsson, Yngve [Chalmers Univ. of Technology, Goeteborg (Sweden); Oversby, Virginia [VMO Konsult, Stockholm (Sweden); Cowper, Mark [AEA Technology, Harwell (United Kingdom)

    2003-10-01

    additional meaningful data. 8) A test procedure that used several short exposures of the sample to solution - the puff test procedure - gave results that showed very little recovery of the spike solution at the end of the tests. Only 10% of the {sup 235}U added as spike was recovered, indicating that 90% of the spike had precipitated onto the solid sample or the iron strip. 9) Tests of UO{sub 2} pellet materials containing {sup 233}U to provide an alpha decay activity similar to that expected for spent fuel 3000 and 10,000 years after disposal showed that the pellet materials behaved as expected under air atmosphere conditions, showing that the manufacturing method was successful. 10) Early testing of the {sup 233}U-doped materials under reducing conditions showed relatively rapid (30 minute) dissolution of small amounts of U at the start of the puff test procedure. Results of analyses of an acidified fraction of the same solutions after 1 or 2 weeks holding indicate that the solutions were inhomogeneous, indicating the presence of colloidal material or small grains of solid. 11) Samples from the {sup 233}U-doped tests initially indicated dissolution of solid during the first week of testing, with some indication of more rapid dissolution of the material with the higher doping. 12) The second cycle of testing of the {sup 233}U-doped materials also showed dissolution occurring during the dilution stages of the puff test. The subsequent week of testing also showed small amounts of further dissolution, with hints that the doped samples were dissolving faster than the undoped samples. 13) At the end of 2 weeks of cycle 2 the remaining solution and solid was transferred to a new reaction vessel, the solution was made up to original volume, and a new dose of spike was added. The results of analyses of [U] and isotopic composition show that the measured U is that expected from dilution of the original solution plus adding the spike. 14) Samples taken during 2 weeks of testing of

  15. Measurement of Henry’s Law constant and infinite dilution activity coefficient of isopropyl mercaptan and isobutyl mercaptan in (methyldiethanolamine (1) + water (2)) with w_1 = 0.25 and 0.50 at temperature of (298 to 348) K using inert gas stripping method

    International Nuclear Information System (INIS)

    Zin, Rohani Mohd; Coquelet, Christophe; Valtz, Alain; Abdul Mutalib, Mohamed I.; Sabil, Khalik Mohamad

    2016-01-01

    Highlights: • Measurement of Henry’s Law constants of nPM, iPM, nBM and iBM in aqueous MDEA. • Measurement of infinite dilution activity coefficients of nPM, iPM, nBM and iBM in aqueous MDEA. • Measurement using gas stripping method for T = (298 to 348) K and MDEA solution of (25 and 50) wt%. • Limiting activity coefficient and Henry’s Law constant is increasing with solute molecular size. • The experimental technique has provided information about heats of solution of aqueous MDEA. - Abstract: In this study, the Henry’s Law constant and the activity coefficients in infinite dilution in a mass fraction of (25 and 50)% of methyldiethanolamine (MDEA) aqueous solution within the temperature range of (298 to 348) K at atmospheric pressure, were measured. An inert gas stripping method was used to perform all the measurements. The new values of Henry’s Law constant and the activity coefficients in infinite dilution correlation with solute molecular size were explained. The influence of the solvent is discussed taking into consideration the heat of absorptions for different MDEA concentrations. Experimental results are compared to literature data wherever available.

  16. Phase diagrams of site diluted ferromagnetic thin film

    International Nuclear Information System (INIS)

    Hamedoun, M.; Bouslykhane, K.; Bakrim, H.; Hourmatallah, A.; Benzakour, N.; Masrour, R.

    2006-01-01

    The phase transition properties of Ising, classical XY and Heisenberg of diluted ferromagnetic thin film are studied by the method of exact high-temperature series expansions extrapolated with the Pade approximants method. The reduced critical temperature τ c of the diluted ferromagnetic thin films is studied as a function of film thickness L and the exchange interactions in the bulk J b , in the surface J s and between surface and nearest-neighbour layer J - bar . It is found that τ c increases with the exchange interactions of surface and L. The magnetic phase diagram (τ c versus dilution x) is obtained. A critical value of the surface exchange interaction above which the surface magnetism appears is obtained. The dependence of the critical parameter of surface reduced coupling R 2 c as a function of the dilution x and the ratio of the exchange interaction between the surface and nearest-neighbour layer to the bulk one R 1 for the three studied models has been investigated. The percolation threshold is defined as the concentration x p at which τ c =0. The obtained values are x p ∼0.2 in the bulk and x p ∼0.4 at the surface

  17. Lung microvascular transport properties measured by multiple indicator dilution methods in patients with adult respiratory distress syndrome. A comparison between patients reversing respiratory failure and those failing to reverse

    International Nuclear Information System (INIS)

    Harris, T.R.; Bernard, G.R.; Brigham, K.L.; Higgins, S.B.; Rinaldo, J.E.; Borovetz, H.S.; Sibbald, W.J.; Kariman, K.; Sprung, C.L.

    1990-01-01

    We conducted indicator dilution studies on the lungs of patients in the early phases of adult respiratory distress syndrome (ARDS) to test the hypothesis that capillary permeability was increased in patients with respiratory failure. Indicator dilution studies were performed using 51Cr-erythrocytes, 125I-albumin, 14C-urea, and 3H-water as tracers. The injectate was infused as a bolus into a central venous line. Peripheral arterial blood was collected and counted for radioactivity. Mathematical analysis of the indicator curves yielded cardiac output, measures of the product of capillary permeability and surface area for urea (PS and D1/2S), the intravascular lung volume (Vv), and the extravascular lung water volume (Ve). Permeability was separated from surface area by normalizing PS and D1/2S to Vv. Patients could be divided into 16 in whom blood gas determinations and radiologic criteria for ARDS were reversed and 23 in whom they were not. We examined indicator dilution and other measures of lung function in the two groups to determine whether significant differences in microvascular function existed. PS and PS/Vv were significantly higher in the nonreversal patients. Ve was above normal, but not different between groups. Linear regression analysis showed significant correlations for all of the following in the nonreversal group: Ve and all measures of permeability, pulmonary vascular resistance (PVR), and the inverse of permeability-surface area measures and AaDO2 and PVR. Only measures of Ve and PS correlated in the reversal group. These results support the hypothesis that capillary permeability is increased in patients with early ARDS and continuing respiratory failure

  18. Electron pairing in dilute liquid metal-metal halide solutions

    Energy Technology Data Exchange (ETDEWEB)

    Selloni, A.; Car, R.; Parrinello, M.; Carnevali, P.

    1987-09-10

    Spin density functional theory is used to describe the interaction between solvated electrons in KCl in the high dilution limit. In agreement with recent calculations based on the path integral method our results for antiparallel spin predict a strong tendency to form localized bielectronic complexes. At variance with numerical path integral, our method can efficiently treat the case of parallel spins. For this case we find that electrons repel each other and localize into separate F-center-like states.

  19. Theoretical modeling of diluted antiferromagnetic systems

    International Nuclear Information System (INIS)

    Pozo, J; Elgueta, R; Acevedo, R

    2000-01-01

    Some magnetic properties of a Diluted Antiferromagnetic System (DAFS) are studied. The model of the two sub-networks for antiferromagnetism is used and a Heisenberg Hamiltonian type is proposed, where the square operators are expressed in terms of boson operators with the approach of spin waves. The behavior of the diluted system's fundamental state depends basically on the competition effect between the anisotropy field and the Weiss molecular field. The approach used allows the diluted system to be worked for strong anisotropies as well as when these are very weak

  20. Vitamin A metabolism, kinetic behavior and utilization: Rationale for the continued development and use of an isotope dilution technique for assessing vitamin A stores in human populations

    International Nuclear Information System (INIS)

    Green, M.H.

    1997-01-01

    The paper discusses the applicability of isotope dilution method in general and oral isotope dilution in particular to the assessment of vitamin A status in humans. It also highlights some aspects of vitamin A intake and metabolism as related to isotope dilution method. Areas of methodological research and development in vitamin A research are also proposed

  1. Preparation of 19-iodo cholesterol labelled with 125 I; Preparacion del 19-yodocolesterol marcado con 125 I

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, L.; Rebollo, D. V.; Ruiz, J. M.

    1986-07-01

    In this paper a new method of synthesis of 19-iodo cholesterol labelled with ''125 I, from commercial cholesterol, is described. Its high chemical (96%) and radiochemical (99.9%) purities high yield and short time of preparation permit us to dispose or a more accessible labelled compound, which results appropriates for clinical investigations and in the diagnosis of disturbances of the suprarenal glands. (Author) 9 refs.

  2. Preparation of 19-iodo cholesterol labelled with 125 I; Preparacion del 19-yodocolesterol marcado con 125 I

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, L; Rebollo, D V; Ruiz, J M

    1986-07-01

    In this paper a new method of synthesis of 19-iodo cholesterol labelled with ''125 I, from commercial cholesterol, is described. Its high chemical (96%) and radiochemical (99.9%) purities high yield and short time of preparation permit us to dispose or a more accessible labelled compound, which results appropriates for clinical investigations and in the diagnosis of disturbances of the suprarenal glands. (Author) 9 refs.

  3. The preparation of glucose uniformly labelled with carbon-14; Preparacion de glucosa uniformemente marcada con carbono-14

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, M D; Suarez, C; Rodrigo, M E

    1978-07-01

    The plant, (Zea mais, L) and culture conditions for an optimum production of glucose has been chosen. To achieve the labelling of glucose, photosynthesis and carboxylation are carried on, under an artificial atmosphere of 14CO{sub 2} produced from 14{sup C}-barium carbonate. Following photosynthesis the sugars are extracted, and then the extract purified by several methods. The purified glucose is finally, degraded and the specific radioactivity is determined in each of its carbon atoms. (Author) 37 refs.

  4. Effect of Welding Parameters on Dilution and Weld Bead Geometry in Cladding

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The effect of pulsed gas metal arc welding (GMAW) variables on the dilution and weld bead geometry in cladding X65 pipeline steel with 316L stainless steel was studied. Using a full factorial method, a series of experiments were carried out to know the effect of wire feed rate, welding speed, distance between gas nozzle and plate, and the vertical angle of welding on dilution and weld bead geometry. The findings indicate that the dilution of weld metal and its dimension i.e. width, height and depth increase with the feed rate, but the contact angle of the bead decreases first and then increases. Meantime, welding speed has an opposite effect except for dilution. There is an interaction effect between welding parameters at the contact angle. The results also show forehand welding or decreasing electrode extension decrease the angle of contact. Finally,a mathematical model is contrived to highlight the relationship between welding variables with dilution and weld bead geometry.

  5. Dilute antiferromagnetism in magnetically doped phosphorene

    Directory of Open Access Journals (Sweden)

    Andrew Allerdt

    2017-11-01

    Full Text Available We study the competition between Kondo physics and indirect exchange on monolayer black phos-phorous using a realistic description of the band structure in combination with the density matrixrenormalization group (DMRG method. The Hamiltonian is reduced to a one-dimensional problemvia an exact canonical transformation that makes it amenable to DMRG calculations, yielding exactresults that fully incorporate the many-body physics. We find that a perturbative description of theproblem is not appropriate and cannot account for the slow decay of the correlations and the completelack of ferromagnetism. In addition, at some particular distances, the impurities decouple formingtheir own independent Kondo states. This can be predicted from the nodes of the Lindhard function.Our results indicate a possible route toward realizing dilute anti-ferromagnetism in phosphorene. Received: 19 September 2017, Accepted: 12 October 2017; Edited by: K. Hallberg; DOI: http://dx.doi.org/10.4279/PIP.090008 Cite as: A Allerdt, A E Feiguin, Papers in Physics 9, 090008 (2017

  6. Preparation of denatured protein bone sterilized with gamma radiation; Preparacion de hueso desproteinizado esterilizado con radiacion gamma

    Energy Technology Data Exchange (ETDEWEB)

    Luna Z, D [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2005-07-01

    The bone is one of the tissues more transplanted in the entire world by that the bone necessity for transplant every day becomes bigger. In the Bank of tissues Radio sterilized of the ININ the amnion and the pig skin are routinely processed. The tissue with which will be continued is with bone. Due to that in our country it doesn't have enough bone of human origin for the necessities required in the bone transplant, an option is the bone of bovine. Of this bone one can obtain denatured protein bone, with the same characteristics of the denatured protein human bone, the one which has been proven that it has good acceptance and incorporation in the human body when is transplanted. The method for the obtaining of the denatured protein bone of bovine, with the confirmation of the final product by means of X-ray diffraction is described. The radiosterilization of this bone with gamma rays and the determination of the lead content. (Author)

  7. Preparation of denatured protein bone sterilized with gamma radiation; Preparacion de hueso desproteinizado esterilizado con radiacion gamma

    Energy Technology Data Exchange (ETDEWEB)

    Luna Z, D. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)]. e-mail: dlz@nuclear.inin.mx

    2005-07-01

    The bone is one of the tissues more transplanted in the entire world by that the bone necessity for transplant every day becomes bigger. In the Bank of tissues Radio sterilized of the ININ the amnion and the pig skin are routinely processed. The tissue with which will be continued is with bone. Due to that in our country it doesn't have enough bone of human origin for the necessities required in the bone transplant, an option is the bone of bovine. Of this bone one can obtain denatured protein bone, with the same characteristics of the denatured protein human bone, the one which has been proven that it has good acceptance and incorporation in the human body when is transplanted. The method for the obtaining of the denatured protein bone of bovine, with the confirmation of the final product by means of X-ray diffraction is described. The radiosterilization of this bone with gamma rays and the determination of the lead content. (Author)

  8. Preparation of extraction resin for radio lanthanides separation; Preparacion de resina de extraccion para separacion de radiolantanidos

    Energy Technology Data Exchange (ETDEWEB)

    Cruz B, C.C. de la; Monroy G, F. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)]. e-mail: delacruzbc@hotmail.com

    2008-07-01

    The present work presents the methodology that was developed for the preparation of one extractant resin with the aim of HDEHP, to separate radio lanthanides with serial atomic numbers. In this case it is exemplified with the separation of the following elements: Gadolinium-161 and the Terbium-161; this last radioisotope it is a beta emitting ({beta}{sup -}) that has a great potential to be used in therapy, also in nuclear medicine and in oncology, this is due to the high penetration power of their {beta}{sup -} particles that can kill to the cancerous cells and to inhibit the growth of the same ones. To be able to separate them it is necessary to appeal to extremely selective separation techniques, since the chemical properties of these elements are very similar. The chromatography is one of the more used analytical tools, this is due to its great sensibility and the selectivity in the compounds separation, in particular the use of the extractive chromatography has shown the feasibility of carrying out this type of separations for this type of elements. The resin with base of HDEHP was absorbed in an inert support under diverse preparation conditions. The extractant properties of the resin, in relation to the elements Gd and Tb (distribution coefficients), its were determined by means of the dynamic method, using as eluent solutions of nitric acid. The Gd-159 was prepared by irradiation of Gd-168 with thermal neutrons and the Tb-161 it is the result of the radioactive decay of the Gd-161 that is produced in turn with the irradiation with neutrons of Gd-160. The coefficients of distribution of Gd and Tb, using the prepared resin under diverse conditions are presented. (Author)

  9. Determination of microquantities of silver in platinum by isotope dilution

    International Nuclear Information System (INIS)

    Yedinakova, V.; Sladkovska, Y.

    1980-01-01

    A method is described for determining microquantities of silver in platinum. It is based on isotope dilution by means of substoichiometric extraction of dithizonates with carbon tetrachloride. The determination of silver according to this technique is not interfered by zinc or gold in quantities exceeding the silver content by one order of magnitude nor by a great excess of platinum. In the presence of copper the addition of complexon is necessary. (author)

  10. S-matrix approach to the equation of state of dilute nuclear matter

    Indian Academy of Sciences (India)

    2014-04-01

    matrix framework, a method is presented to calculate the equation of state of dilute warm nuclear matter. The result is a model-independent virial series for the pressure and density that systematically includes contributions from ...

  11. Crystal Fields in Dilute Rare-Earth Metals Obtained from Magnetization Measurements on Dilute Rare-Earth Alloys

    DEFF Research Database (Denmark)

    Touborg, P.; Høg, J.

    1974-01-01

    Crystal field parameters of Tb, Dy, and Er in Sc, Y, and Lu are summarized. These parameters are obtained from magnetization measurements on dilute single crystals, and successfully checked by a number of different methods. The crystal field parameters vary unpredictably with the rare-earth solute....... B40, B60, and B66 are similar in Y and Lu. Crystal field parameters for the pure metals Tb, Dy, and Er are estimated from the crystal fields in Y and Lu....

  12. Reduction of measurement uncertainty by experimental design in high-order (double, triple, and quadruple) isotope dilution mass spectrometry: application to GC-MS measurement of bromide.

    Science.gov (United States)

    Pagliano, Enea; Mester, Zoltán; Meija, Juris

    2013-03-01

    Since its introduction a century ago, isotope dilution analysis has played a central role in developments of analytical chemistry. This method has witnessed many elaborations and developments over the years. To date, we have single, double, and even triple isotope dilution methods. In this manuscript, we summarize the conceptual aspects of isotope dilution methods and introduce the quadruple dilution and the concept of exact matching triple and quadruple dilutions. The comparison of isotope dilution methods is performed by determination of bromide ions in groundwater using novel ethyl-derivatization chemistry in conjunction with GC/MS. We show that the benefits of higher-order isotope dilution methods are countered with a greater need for careful experimental design of the isotopic blends. Just as for ID(2)MS, ID(3)MS and ID(4)MS perform best when the isotope ratio of one sample/spike blend is matched with that of a standard/spike blend (exact matching).

  13. Properties of magnetically diluted nanocrystals prepared by mechanochemical route

    International Nuclear Information System (INIS)

    Balaz, P.; Skorvanek, I.; Fabian, M.; Kovac, J.; Steinbach, F.; Feldhoff, A.; Sepelak, V.; Jiang, J.; Satka, A.; Kovac, J.

    2010-01-01

    The bulk and surface properties of magnetically diluted Cd 0.6 Mn 0.4 S nanocrystals synthesized by solid state route in a planetary mill were studied. XRD, SEM, TEM (HRTEM), low-temperature N 2 sorption, nanoparticle size distribution as well as SQUID magnetometry methods have been applied. The measurements identified the aggregates of small nanocrystals, 5-10 nm in size. The homogeneity of produced particles with well developed specific surface area (15-66 m 2 g -1 ) was documented. The transition from the paramagnetic to the spin-glass-like phase has been observed below ∼40 K. The changes in the magnetic behaviour at low temperatures seem to be correlated with the formation of the new surface area as a consequence of milling. The magnetically diluted Cd 0.6 Mn 0.4 S nanocrystals are obtained in the simple synthesis step, making the process attractive for industrial applications.

  14. Infinitely dilute partial molar properties of proteins from computer simulation.

    Science.gov (United States)

    Ploetz, Elizabeth A; Smith, Paul E

    2014-11-13

    A detailed understanding of temperature and pressure effects on an infinitely dilute protein's conformational equilibrium requires knowledge of the corresponding infinitely dilute partial molar properties. Established molecular dynamics methodologies generally have not provided a way to calculate these properties without either a loss of thermodynamic rigor, the introduction of nonunique parameters, or a loss of information about which solute conformations specifically contributed to the output values. Here we implement a simple method that is thermodynamically rigorous and possesses none of the above disadvantages, and we report on the method's feasibility and computational demands. We calculate infinitely dilute partial molar properties for two proteins and attempt to distinguish the thermodynamic differences between a native and a denatured conformation of a designed miniprotein. We conclude that simple ensemble average properties can be calculated with very reasonable amounts of computational power. In contrast, properties corresponding to fluctuating quantities are computationally demanding to calculate precisely, although they can be obtained more easily by following the temperature and/or pressure dependence of the corresponding ensemble averages.

  15. Computer automation of a dilution cryogenic system

    International Nuclear Information System (INIS)

    Nogues, C.

    1992-09-01

    This study has been realized in the framework of studies on developing new technic for low temperature detectors for neutrinos and dark matter. The principles of low temperature physics and helium 4 and dilution cryostats, are first reviewed. The cryogenic system used and the technic for low temperature thermometry and regulation systems are then described. The computer automation of the dilution cryogenic system involves: numerical measurement of the parameter set (pressure, temperature, flow rate); computer assisted operating of the cryostat and the pump bench; numerical regulation of pressure and temperature; operation sequence full automation allowing the system to evolve from a state to another (temperature descent for example)

  16. Interaction Studies of Dilute Aqueous Oxalic Acid

    Directory of Open Access Journals (Sweden)

    Kiran Kandpal

    2007-01-01

    Full Text Available Molecular conductance λm, relative viscosity and density of oxalicacid at different concentration in dilute aqueous solution were measured at 293 K.The conductance data were used to calculate the value association constant.Viscosity and density data were used to calculate the A and B coefficient ofJone-Dole equation and apparent molar volume respectively. The viscosityresults were utilized for the applicability of Modified Jone-Dole equation andStaurdinger equations. Mono oxalate anion acts, as structure maker and thesolute-solvent interaction were present in the dilute aqueous oxalic acid.

  17. Dilution refrigeration with multiple mixing chambers

    International Nuclear Information System (INIS)

    Coops, G.M.

    1981-01-01

    A dilution refrigerator is an instrument to reach temperatures in the mK region in a continuous way. The temperature range can be extended and the cooling power can be enlarged by adding an extra mixing chamber. In this way we obtain a double mixing chamber system. In this thesis the theory of the multiple mixing chamber is presented and tested on its validity by comparison with the measurements. Measurements on a dilution refrigerator with a circulation rate up to 2.5 mmol/s are also reported. (Auth.)

  18. Chiral-glass transition in a diluted dipolar-interaction Heisenberg system

    International Nuclear Information System (INIS)

    Zhang Kaicheng; Liu Guibin; Zhu Yan

    2011-01-01

    Recently, numerical simulations reveal that a spin-glass transition can occur in the three-dimensional diluted dipolar system. By defining the chirality of triple spins in a diluted dipolar Heisenberg spin glass, we study the chiral ordering in the system using parallel tempering algorithm and heat bath method. The finite-size scaling analysis reveals that the system undergoes a chiral-glass transition at finite temperature. - Highlights: → We define the chirality in a diluted dipolar Heisenberg system. → The system undergoes a chiral-glass transition at finite temperature. → We extract the critical exponents of the chiral-glass transition.

  19. Quantifying dilution caused by execution efficiency

    Directory of Open Access Journals (Sweden)

    Taís Renata Câmara

    Full Text Available Abstract In open pit mining, dilution is not always a factor systematically analyzed and calculated. Often it is only an adjusted number, for example, calculated or even empirically determined for a certain operational condition perpetuating along time in the form of a constant applied to calculating reserves or mine planning in attendance of audit requirements. Dilution and loss are factors that should be always considered for tonnage and grade estimates. These factors are always associated and can be determined considering several particularities of the deposit and the operation itself. In this study, a methodology was determined to identify blocks adjacent to the blocks previously planned to be mined. Thus, it is possible to estimate the dilution caused by poor operating efficiency, taking into account the inability of the equipment to perfectly remove each block, respecting its limits. Mining dilution is defined as the incorporation of waste material to ore due to the operational incapacity to efficiently separate the materials during the mining process, considering the physical processes, and the operating and geometric configurations of the mining with the equipment available.

  20. Atomic displacements in bcc dilute alloys

    Indian Academy of Sciences (India)

    be attributed to the reliability of the measured distances which fall off quickly with each shell. Therefore, in ... field and electrical field gradients due to impurities in vanadium [13]. The effective .... Expanding ∆φ(| Rn' |) in power series of u(R0 n), one gets ... The results of each dilute alloy system are presented separately and ...

  1. A century of indicator dilution technique

    DEFF Research Database (Denmark)

    Henriksen, Jens H; Jensen, Gorm B; Larsson, Henrik B W

    2014-01-01

    This review imparts the history and the present status of the indicator dilution technique with quantitative bolus injection. The first report on flow measurement with this technique appeared 100 years ago. In 1928, the use of intravascular dyes made possible a widespread application in animals...

  2. Liquid volumes measurements by isotopic dilution

    International Nuclear Information System (INIS)

    Herrera M, J.M.

    1981-01-01

    By the nuclear technique, isotopic dilution industrial liquid volumes may be measured in large size recipients of irregular shapes using radiotracers. In the present work laboratory and pilot test are made with 2 radiotracers for optimizing the technique and later done on an industrial scale, obtaining a maximum deviation of +-2%, some recommendations are given to improve the performance of the technique. (author)

  3. Continuous deionization of a dilute nickel solution

    NARCIS (Netherlands)

    Spoor, P.B.; Koene, L.; Veen, ter W.R.; Janssen, L.J.J.

    2002-01-01

    This paper describes the continuous removal of nickel ions from a dilute solution using a hybrid ion-exchange/electrodialysis process. Emphasis was placed on the ionic state of the bed during the process, and the mass balance of ions in the system. Much of this information was obtained by analysing

  4. Dilution kicker for the SPS beam dump

    CERN Multimedia

    1974-01-01

    In order to reduce thermal stress on the SPS dump material, the fast-ejected beam was swept horizontally across the dump. This was done with the "dilution kicker" MKDH, still in use at the time of writing. The person on the left is Manfred Mayer. See also 7404072X.

  5. Magnetic properties of diluted magnetic semiconductors

    NARCIS (Netherlands)

    Jonge, de W.J.M.; Swagten, H.J.M.

    1991-01-01

    A review will be given of the magnetic characteristics of diluted magnetic semiconductors and the relation with the driving exchange mechanisms. II–VI as well as IV–VI compounds will be considered. The relevance of the long-range interaction and the role of the carrier concentration will be

  6. CALCULATING THE EFFECT OF EMPLOYEE STOCK OPTIONS ON DILUTED EPS

    OpenAIRE

    van Zyl, Warrick Boyd

    2007-01-01

    This paper focuses on how to calculate diluted earnings per share (DEPS) when a firm has outstanding employee stock options (ESOs). Three possible methods are described and compared. The first is the current International Accounting Standard 33 – Earnings Per Share (IAS 33) approach which is based on the intrinsic value of the ESOs. The second method, advocated by Core et al. (2002), is very similar to that of IAS 33 but instead of the intrinsic value uses the fair value of the outstanding...

  7. The diluted tri-dimensional spin-one Ising model with crystal field interactions

    International Nuclear Information System (INIS)

    Saber, M.

    1988-09-01

    3D spin-one Ising models with nearest-neighbour ferromagnetic interactions with crystal-field exhibit tricritical behaviour. A new method that applies to a wide class of random systems is used to study the influence of site and bond dilution on this behaviour. We have calculated temperature-crystal-field-concentration phase diagrams and determined, in particular, the influence of dilution on the zero temperature tricritical temperature. (author). 10 refs, 8 figs

  8. Determination of diffusion coefficients of various livestock antibiotics in water at infinite dilution

    Directory of Open Access Journals (Sweden)

    Soriano Allan N.

    2017-01-01

    Full Text Available The fate of antibiotics entering the environment raised concerns on the possible effect of antimicrobial resistance bacteria. Prediction of the fate and transport of these particles are needed to be determined, significantly the diffusion coefficient of antibiotic in water at infinite dilution. A systematic determination of diffusion coefficient of antibiotic in water at infinite dilution of five different kinds of livestock antibiotics namely: Amtyl, Ciprotyl, Doxylak Forte, Trisullak, and Vetracin Gold in the 293.15 to 313.15 K temperature range are reported through the use of the method involving the electrolytic conductivity measurements. A continuous stirred tank reactor is utilized to measure the electrolytic conductivities of the considered systems. These conductivities are correlated by using the Nernst-Haskell equation to determine the infinite dilution diffusion coefficient. Determined diffusion coefficients are based on the assumption that in dilute solution, these antibiotics behave as strong electrolyte from which H+ cation dissociate from the antibiotic’s anion.

  9. Determination of diffusion coefficients of various livestock antibiotics in water at infinite dilution

    Science.gov (United States)

    Soriano, Allan N.; Adamos, Kristoni G.; Bonifacio, Pauline B.; Adornado, Adonis P.; Bungay, Vergel C.; Vairavan, Rajendaran

    2017-11-01

    The fate of antibiotics entering the environment raised concerns on the possible effect of antimicrobial resistance bacteria. Prediction of the fate and transport of these particles are needed to be determined, significantly the diffusion coefficient of antibiotic in water at infinite dilution. A systematic determination of diffusion coefficient of antibiotic in water at infinite dilution of five different kinds of livestock antibiotics namely: Amtyl, Ciprotyl, Doxylak Forte, Trisullak, and Vetracin Gold in the 293.15 to 313.15 K temperature range are reported through the use of the method involving the electrolytic conductivity measurements. A continuous stirred tank reactor is utilized to measure the electrolytic conductivities of the considered systems. These conductivities are correlated by using the Nernst-Haskell equation to determine the infinite dilution diffusion coefficient. Determined diffusion coefficients are based on the assumption that in dilute solution, these antibiotics behave as strong electrolyte from which H+ cation dissociate from the antibiotic's anion.

  10. Fast and accurate calculation of dilute quantum gas using Uehling–Uhlenbeck model equation

    Energy Technology Data Exchange (ETDEWEB)

    Yano, Ryosuke, E-mail: ryosuke.yano@tokiorisk.co.jp

    2017-02-01

    The Uehling–Uhlenbeck (U–U) model equation is studied for the fast and accurate calculation of a dilute quantum gas. In particular, the direct simulation Monte Carlo (DSMC) method is used to solve the U–U model equation. DSMC analysis based on the U–U model equation is expected to enable the thermalization to be accurately obtained using a small number of sample particles and the dilute quantum gas dynamics to be calculated in a practical time. Finally, the applicability of DSMC analysis based on the U–U model equation to the fast and accurate calculation of a dilute quantum gas is confirmed by calculating the viscosity coefficient of a Bose gas on the basis of the Green–Kubo expression and the shock layer of a dilute Bose gas around a cylinder.

  11. Determination of the maximum inhibitory dilution of cetylpyridinium chloride-based mouthwashes against staphylococcus aureus: an in vitro study

    Directory of Open Access Journals (Sweden)

    Evandro Watanabe

    2008-08-01

    Full Text Available The aim of this in vitro study was to determine the maximum inhibitory dilution (MID of four cetylpyridinium chloride (CPC-based mouthwashes: CPC+Propolis, CPC+Malva, CPC+Eucaliptol+Juá+Romã+Propolis (Natural Honey® and CPC (Cepacol®, against 28 Staphylococcus aureus field strains, using the agar dilution method. Decimal dilutions ranging from 1/10 to 1/655,360 were prepared and added to Mueller Hinton Agar. Strains were inoculated using Steers multipoint inoculator. The inocula were seeded onto the surface of the culture medium in Petri dishes containing different dilutions of the mouthwashes. The dishes were incubated at 37ºC for 24 h. For readings, the MID was considered as the maximum dilution of mouthwash still capable of inhibiting microbial growth. The obtained data showed that CPC+Propolis had antimicrobial activity against 27 strains at 1/320 dilution and against all 28 strains at 1/160 dilution, CPC+Malva inhibited the growth of all 28 strains at 1/320 dilution, CPC+Eucaliptol+Juá+Romã+Propolis inhibited the growth of 2 strains at 1/640 dilution and all 28 strains at 1/320 dilution, and Cepacol® showed antimicrobial activity against 3 strains at 1/320 dilution and against all 28 strains at 1/160 dilution. Data were submitted to Kruskal-Wallis test, showing that the MID of Cepacol® was lower than that determined for the other products (p<0.05. In conclusion, CPC-mouthwashes showed antimicrobial activity against S. aureus and the addition of other substances to CPC improved its antimicrobial effect.

  12. EXAFS of dilute systems: fluorescence detection

    International Nuclear Information System (INIS)

    Hastings, J.B.

    1979-01-01

    Since the first observations of the variation of the absorption coefficient for x-rays above the energy thresholds in the thirties until the early seventies, measurements and analysis of these variations were merely intended for the understanding of the underlying physics. Recently, with the understanding of the information available about the local atomic structure in the neighborhood of the absorbing species and the availability of high intensity synchrotron radiation sources, EXAFS has become a powerful structural tool. In these discussions, the details of the measurements for very dilute species are presented. It is shown that for the more dilute systems the measurement of the emission rather than the direct absorption is a more favorable technique

  13. Phase diagrams of diluted transverse Ising nanowire

    Energy Technology Data Exchange (ETDEWEB)

    Bouhou, S.; Essaoudi, I. [Laboratoire de Physique des Matériaux et Modélisation, des Systèmes, (LP2MS), Unité Associée au CNRST-URAC 08, University of Moulay Ismail, Physics Department, Faculty of Sciences, B.P. 11201 Meknes (Morocco); Ainane, A., E-mail: ainane@pks.mpg.de [Laboratoire de Physique des Matériaux et Modélisation, des Systèmes, (LP2MS), Unité Associée au CNRST-URAC 08, University of Moulay Ismail, Physics Department, Faculty of Sciences, B.P. 11201 Meknes (Morocco); Max-Planck-Institut für Physik Complexer Systeme, Nöthnitzer Str. 38 D-01187 Dresden (Germany); Saber, M. [Laboratoire de Physique des Matériaux et Modélisation, des Systèmes, (LP2MS), Unité Associée au CNRST-URAC 08, University of Moulay Ismail, Physics Department, Faculty of Sciences, B.P. 11201 Meknes (Morocco); Max-Planck-Institut für Physik Complexer Systeme, Nöthnitzer Str. 38 D-01187 Dresden (Germany); Ahuja, R. [Condensed Matter Theory Group, Department of Physics and Astronomy, Uppsala University, 75120 Uppsala (Sweden); Dujardin, F. [Laboratoire de Chimie et Physique des Milieux Complexes (LCPMC), Institut de Chimie, Physique et Matériaux (ICPM), 1 Bd. Arago, 57070 Metz (France)

    2013-06-15

    In this paper, the phase diagrams of diluted Ising nanowire consisting of core and surface shell coupling by J{sub cs} exchange interaction are studied using the effective field theory with a probability distribution technique, in the presence of transverse fields in the core and in the surface shell. We find a number of characteristic phenomena. In particular, the effect of concentration c of magnetic atoms, the exchange interaction core/shell, the exchange in surface and the transverse fields in core and in surface shell of phase diagrams are investigated. - Highlights: ► We use the EFT to investigate the phase diagrams of Ising transverse nanowire. ► Ferrimagnetic and ferromagnetic cases are investigated. ► The effects of the dilution and the transverse fields in core and shell are studied. ► Behavior of the transition temperature with the exchange interaction is given.

  14. Phase diagrams of diluted transverse Ising nanowire

    International Nuclear Information System (INIS)

    Bouhou, S.; Essaoudi, I.; Ainane, A.; Saber, M.; Ahuja, R.; Dujardin, F.

    2013-01-01

    In this paper, the phase diagrams of diluted Ising nanowire consisting of core and surface shell coupling by J cs exchange interaction are studied using the effective field theory with a probability distribution technique, in the presence of transverse fields in the core and in the surface shell. We find a number of characteristic phenomena. In particular, the effect of concentration c of magnetic atoms, the exchange interaction core/shell, the exchange in surface and the transverse fields in core and in surface shell of phase diagrams are investigated. - Highlights: ► We use the EFT to investigate the phase diagrams of Ising transverse nanowire. ► Ferrimagnetic and ferromagnetic cases are investigated. ► The effects of the dilution and the transverse fields in core and shell are studied. ► Behavior of the transition temperature with the exchange interaction is given

  15. Redox substoichiometry in isotope dilution analysis Pt. 2

    International Nuclear Information System (INIS)

    Kambara, T.; Suzuki, J.; Yoshioka, H.; Nakajima, N.

    1978-01-01

    Isotope dilution analysis using the redox substoichiometric principle has been applied to the determination of antimony content in metallic zinc. As the substoichiometric reaction, the oxidation of trivalent to pentavalent antimony with potassium permanganate was used, followed by separation of these species by the BHPA extraction of trivalent antimony. Determination of antimony contents less than 0.5 μg was found to be possible with good accuracy, without separation of zinc ions. The antimony content in a metallic zinc sample was determined to be 19.7+-0.8 ppm, in good agreement with the results obtained by the other analytical methods. (author)

  16. Fractal effects on excitations in diluted ferromagnets

    International Nuclear Information System (INIS)

    Kumar, D.

    1981-08-01

    The low energy spin-wave like excitations in diluted ferromagnets near percolation threshold are studied. For this purpose an explicit use of the fractal model for the backbone of the infinite percolating cluster due to Kirkpatrick is made. Three physical effects are identified, which cause the softening of spin-waves as the percolation point is approached. The importance of fractal effects in the calculation of density of states and the low temperature thermodynamics is pointed out. (author)

  17. Dilution physics modeling: Dissolution/precipitation chemistry

    International Nuclear Information System (INIS)

    Onishi, Y.; Reid, H.C.; Trent, D.S.

    1995-09-01

    This report documents progress made to date on integrating dilution/precipitation chemistry and new physical models into the TEMPEST thermal-hydraulics computer code. Implementation of dissolution/precipitation chemistry models is necessary for predicting nonhomogeneous, time-dependent, physical/chemical behavior of tank wastes with and without a variety of possible engineered remediation and mitigation activities. Such behavior includes chemical reactions, gas retention, solids resuspension, solids dissolution and generation, solids settling/rising, and convective motion of physical and chemical species. Thus this model development is important from the standpoint of predicting the consequences of various engineered activities, such as mitigation by dilution, retrieval, or pretreatment, that can affect safe operations. The integration of a dissolution/precipitation chemistry module allows the various phase species concentrations to enter into the physical calculations that affect the TEMPEST hydrodynamic flow calculations. The yield strength model of non-Newtonian sludge correlates yield to a power function of solids concentration. Likewise, shear stress is concentration-dependent, and the dissolution/precipitation chemistry calculations develop the species concentration evolution that produces fluid flow resistance changes. Dilution of waste with pure water, molar concentrations of sodium hydroxide, and other chemical streams can be analyzed for the reactive species changes and hydrodynamic flow characteristics

  18. Nutritional assessment by isotope dilution analysis of body composition

    International Nuclear Information System (INIS)

    Szeluga, D.J.; Stuart, R.K.; Utermohlen, V.; Santos, G.W.

    1984-01-01

    The three components of body mass, body cell mass (BCM), extracellular fluid (ECF), and fat + extracellular solids (ECS: bone, tendon, etc) can be quantified using established isotope dilution techniques. With these techniques, total body water (TBW) and ECF are measured using 3H 2 O and 82 Bromine, respectively, as tracers. BCM is calculated from intracellular fluid (ICF) where ICF . TBW - ECF. Fat + ECS is estimated as: body weight - (BCM + ECF). TBW and ECF can be determined by either of two calculation methods, one requiring several timed plasma samples (extrapolation method) and one requiring a single plasma sample and a 4-h urine collection (urine-corrected method). The comparability of the two calculation methods was evaluated in 20 studies in 12 bone marrow transplant recipients. We found that for determination of TBW and ECF there was a very strong linear relationship (r2 greater than 0.98) between the calculation methods. Further comparisons (by t test, 2-sided) indicated that for the determination of ECF, the methods were not significantly (p greater than 0.90) different; however, TBW determined by the urine-corrected method was slightly (0.1 to 6%), but significantly (p less than 0.01) greater than that determined by the extrapolation method. Therefore, relative to the extrapolation method, the urine-corrected method ''over-estimates'' BCM and ''under-estimates'' fat + ECS since determination of these compartment sizes depends on measurement of TBW. We currently use serial isotope dilution studies to monitor the body composition changes of patients receiving therapeutic nutritional support

  19. Optimization and validation of a method for the determination of the refractive index of milk serum based on the reaction between milk and copper(II) sulfate to detect milk dilutions.

    Science.gov (United States)

    Rezende, Patrícia Sueli; Carmo, Geraldo Paulo do; Esteves, Eduardo Gonçalves

    2015-06-01

    We report the use of a method to determine the refractive index of copper(II) serum (RICS) in milk as a tool to detect the fraudulent addition of water. This practice is highly profitable, unlawful, and difficult to deter. The method was optimized and validated and is simple, fast and robust. The optimized method yielded statistically equivalent results compared to the reference method with an accuracy of 0.4% and quadrupled analytical throughput. Trueness, precision (repeatability and intermediate precision) and ruggedness are determined to be satisfactory at a 95.45% confidence level. The expanded uncertainty of the measurement was ±0.38°Zeiss at the 95.45% confidence level (k=3.30), corresponding to 1.03% of the minimum measurement expected in adequate samples (>37.00°Zeiss). Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Molecular analysis of two mouse dilute locus deletion mutations: Spontaneous dilute lethal20J and radiation-induced dilute prenatal lethal Aa2 alleles

    International Nuclear Information System (INIS)

    Strobel, M.C.; Seperack, P.K.; Copeland, N.G.; Jenkins, N.A.

    1990-01-01

    The dilute (d) coat color locus of mouse chromosome 9 has been identified by more than 200 spontaneous and mutagen-induced recessive mutations. With the advent of molecular probes for this locus, the molecular lesion associated with different dilute alleles can be recognized and precisely defined. In this study, two dilute mutations, dilute-lethal20J (dl20J) and dilute prenatal lethal Aa2, have been examined. Using a dilute locus genomic probe in Southern blot analysis, we detected unique restriction fragments in dl20J and Aa2 DNA. Subsequent analysis of these fragments showed that they represented deletion breakpoint fusion fragments. DNA sequence analysis of each mutation-associated deletion breakpoint fusion fragment suggests that both genomic deletions were generated by nonhomologous recombination events. The spontaneous dl20J mutation is caused by an interstitial deletion that removes a single coding exon of the dilute gene. The correlation between this discrete deletion and the expression of all dilute-associated phenotypes in dl20J homozygotes defines the dl20J mutation as a functional null allele of the dilute gene. The radiation-induced Aa2 allele is a multilocus deletion that, by complementation analysis, affects both the dilute locus and the proximal prenatal lethal-3 (pl-3) functional unit. Molecular analysis of the Aa2 deletion breakpoint fusion fragment has provided access to a previously undefined gene proximal to d. Initial characterization of this new gene suggests that it may represent the genetically defined pl-3 functional unit

  1. Automatic processing of isotopic dilution curves obtained by precordial detection

    International Nuclear Information System (INIS)

    Verite, J.C.

    1973-01-01

    Dilution curves pose two distinct problems: that of their acquisition and that of their processing. A study devoted to the latter aspect only was presented. It was necessary to satisfy two important conditions: the treatment procedure, although applied to a single category of curves (isotopic dilution curves obtained by precordial detection), had to be as general as possible; to allow dissemination of the method the equipment used had to be relatively modest and inexpensive. A simple method, considering the curve processing as a process identification, was developed and should enable the mean heart cavity volume and certain pulmonary circulation parameters to be determined. Considerable difficulties were encountered, limiting the value of the results obtained though not condemning the method itself. The curve processing question raised the problem of their acquisition, i.e. the number of these curves and their meaning. A list of the difficulties encountered is followed by a set of possible solutions, a solution being understood to mean a curve processing combination where the overlapping between the two aspects of the problem is accounted for [fr

  2. Relative volatility of dilute solutions of Rb-Cs system

    International Nuclear Information System (INIS)

    Gromov, P.B.; Izotov, V.P.; Nisel'son, L.A.

    1984-01-01

    Relative volatility of diluted solutions Rb-Cs in the temperature range 650-820 K and pressures 13-200 gPa has been studied. The system Rb-Cs in the range of diluted solutions obeys the Henry law. It is shown, that liquid-vapour equilibrium in diluted solutions of cesium in rubidium is characterized by negative deviation from perfection

  3. Creatine Supplementation Increases Total Body Water in Soccer Players: a Deuterium Oxide Dilution Study.

    Science.gov (United States)

    Deminice, R; Rosa, F T; Pfrimer, K; Ferrioli, E; Jordao, A A; Freitas, E

    2016-02-01

    This study aimed to evaluate changes in total body water (TBW) in soccer athletes using a deuterium oxide dilution method and bioelectrical impedance (BIA) formulas after 7 days of creatine supplementation. In a double-blind controlled manner, 13 healthy (under-20) soccer players were divided randomly in 2 supplementation groups: Placebo (Pla, n=6) and creatine supplementation (CR, n=7). Before and after the supplementation period (0.3 g/kg/d during 7 days), TBW was determined by deuterium oxide dilution and BIA methods. 7 days of creatine supplementation lead to a large increase in TBW (2.3±1.0 L) determined by deuterium oxide dilution, and a small but significant increase in total body weight (1.0±0.4 kg) in Cr group compared to Pla. The Pla group did not experience any significant changes in TBW or body weight. Although 5 of 6 BIA equations were sensitive to determine TBW changes induced by creatine supplementation, the Kushner et al. 16 method presented the best concordance levels when compared to deuterium dilution method. In conclusion, 7-days of creatine supplementation increased TBW determined by deuterium oxide dilution or BIA formulas. BIA can be useful to determine TBW changes promoted by creatine supplementation in soccer athletes, with special concern for formula choice. © Georg Thieme Verlag KG Stuttgart · New York.

  4. Polaron in the dilute critical Bose condensate

    Science.gov (United States)

    Pastukhov, Volodymyr

    2018-05-01

    The properties of an impurity immersed in a dilute D-dimensional Bose gas at temperatures close to its second-order phase transition point are considered. Particularly by means of the 1/N-expansion, we calculate the leading-order polaron energy and the damping rate in the limit of vanishing boson–boson interaction. It is shown that the perturbative effective mass and the quasiparticle residue diverge logarithmically in the long-length limit, signalling the non-analytic behavior of the impurity spectrum and pole-free structure of the polaron Green’s function in the infrared region, respectively.

  5. Confluence Model or Resource Dilution Hypothesis?

    DEFF Research Database (Denmark)

    Jæger, Mads

    have a negative effect on educational attainment most studies cannot distinguish empirically between the CM and the RDH. In this paper, I use the different theoretical predictions in the CM and the RDH on the role of cognitive ability as a partial or complete mediator of the sibship size effect......Studies on family background often explain the negative effect of sibship size on educational attainment by one of two theories: the Confluence Model (CM) or the Resource Dilution Hypothesis (RDH). However, as both theories – for substantively different reasons – predict that sibship size should...

  6. Neutron scattering study of dilute supercritical solutions

    International Nuclear Information System (INIS)

    Cochran, H.D.; Wignall, G.D.; Shah, V.M.; Londono, J.D.; Bienkowski, P.R.

    1994-01-01

    Dilute solutions in supercritical solvents exhibit interesting microstructures that are related to their dramatic macroscopic behavior. In typical attractive solutions, solutes are believed to be surrounded by clusters of solvent molecules, and solute molecules are believed to congregate in the vicinity of one another. Repulsive solutions, on the other hand, exhibit a local region of reduced solvent density around the solute with solute-solute congregation. Such microstructures influence solubility, partial molar volume, reaction kinetics, and many other properties. We have undertaken to observe these interesting microstructures directly by neutron scattering experiments on dilute noble gas systems including Ar. The three partial structure factors for such systems and the corresponding pair correlation functions can be determined by using the isotope substitution technique. The systems studied are uniquely suited for our objectives because of the large coherent neutron scattering length of the isotope 36 Ar and because of the accurate potential energy functions that are available for use in molecular simulations and theoretical calculations to be compared with the scattering results. We will describe our experiment, the unique apparatus we have built for it, and the neutron scattering results from our initial allocations of beam time. We will also describe planned scattering experiments to follow those with noble gases, including study of long-chain molecules in supercritical solvents. Such studies will involve hydrocarbon mixtures with and without deuteration to provide contrast

  7. Universal water-dilutable inhibited protective lubricants

    International Nuclear Information System (INIS)

    Mamtseva, M.V.; Kardash, N.V.; Latynina, M.B.

    1993-01-01

    In the interest of environmental protection, improvement of working conditions, and reduced fire hazard in production operations, water-based protective lubricants are now available in a wide assortment, and the production volume has increased greatly. The term water-dilutable inhibited protective lubricants (WDIPL) means water-soluble, water-emulsifiable, or water-dispersible products with the dual function of reducing friction and wear and protecting metal surfaces against corrosion for specified periods of time. According to the standard Unified System of Protection Against Corrosion and Aging (COST 9.103-78), WDIPLs are classed as products for the temporary corrosion protection of metals and end-items. In the general class of WDIPLs one can identify water-dilutable combination corrosion inhibitors, film-forming inhibited petroleum compositions (FIPC-d), detergent-preservative fluids, operational-preservative lubricating-cooling process compounds (ICPC), and, finally, universal multifunctional products. Combined corrosion inhibitors may consist of water-soluble organic and inorganic compounds; water/oil and oil-soluble surfactants - corrosion inhibitors of the chemisorption type or donor and/or acceptor types; shielding inhibitors of the adsorption type; and fast-acting water-displacing components. 23 refs

  8. Capsize of polarization in dilute photonic crystals.

    Science.gov (United States)

    Gevorkian, Zhyrair; Hakhoumian, Arsen; Gasparian, Vladimir; Cuevas, Emilio

    2017-11-29

    We investigate, experimentally and theoretically, polarization rotation effects in dilute photonic crystals with transverse permittivity inhomogeneity perpendicular to the traveling direction of waves. A capsize, namely a drastic change of polarization to the perpendicular direction is observed in a one-dimensional photonic crystal in the frequency range 10 ÷ 140 GHz. To gain more insights into the rotational mechanism, we have developed a theoretical model of dilute photonic crystal, based on Maxwell's equations with a spatially dependent two dimensional inhomogeneous dielectric permittivity. We show that the polarization's rotation can be explained by an optical splitting parameter appearing naturally in Maxwell's equations for magnetic or electric fields components. This parameter is an optical analogous of Rashba like spin-orbit interaction parameter present in quantum waves, introduces a correction to the band structure of the two-dimensional Bloch states, creates the dynamical phase shift between the waves propagating in the orthogonal directions and finally leads to capsizing of the initial polarization. Excellent agreement between theory and experiment is found.

  9. Impaired Urine Dilution Capability in HIV Stable Patients

    Directory of Open Access Journals (Sweden)

    Waldo H. Belloso

    2014-01-01

    Full Text Available Renal disease is a well-recognized complication among patients with HIV infection. Viral infection itself and the use of some antiretroviral drugs contribute to this condition. The thick ascending limb of Henle’s loop (TALH is the tubule segment where free water clearance is generated, determining along with glomerular filtration rate the kidney’s ability to dilute urine. Objective. We analyzed the function of the proximal tubule and TALH in patients with HIV infection receiving or not tenofovir-containing antiretroviral treatment in comparison with healthy seronegative controls, by applying a tubular physiological test, hyposaline infusion test (Chaimowitz’ test. Material & Methods. Chaimowitz’ test was performed on 20 HIV positive volunteers who had normal renal functional parameters. The control group included 10 healthy volunteers. Results. After the test, both HIV groups had a significant reduction of serum sodium and osmolarity compared with the control group. Free water clearance was lower and urine osmolarity was higher in both HIV+ groups. Proximal tubular function was normal in both studied groups. Conclusion. The present study documented that proximal tubule sodium reabsorption was preserved while free water clearance and maximal urine dilution capability were reduced in stable HIV patients treated or not with tenofovir.

  10. Investigation of Possible Maillard Reaction Between Acyclovir and Dextrose upon Dilution Prior to Parenteral Administration.

    Science.gov (United States)

    Siahi Shadbad, Mohammad Reza; Ghaderi, Faranak; Hatami, Leila; Monajjemzadeh, Farnaz

    2016-12-01

    In this study the stability of parenteral acyclovir (ACV) when diluted in dextrose (DEX) as large volume intravenous fluid preparation (LVIF) was evaluated and the possible Maillard reaction adducts were monitored in the recommended infusion time. Different physicochemical methods were used to evaluate the Maillard reaction of dextrose with ACV to track the reaction in real infusion condition. Other large volume intravenous fluids were checked regarding the diluted drug stability profile. Differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and mass data proved the reaction of glucose with dextrose. A Maillard-specific high performance liquid chromatography (HPLC) method was used to track the reaction in real infusion condition in vitro. The nucleophilic reaction occurred in diluted parenteral preparations of acyclovir in 5% dextrose solutions. The best diluent solution was also selected as sodium chloride and introduced based on drug stability and also its adsorption onto different infusion sets (PVC or non PVC) to provide an acceptable administration protocol in clinical practices. Although, the Maillard reaction was proved and successfully tracked in diluted solutions, and the level of drug loss when diluted in dextrose was reported to be between 0.27 up to 1.03% of the initial content. There was no drug adsorption to common infusion sets. The best diluent for parenteral acyclovir is sodium chloride large volume intravenous fluid.

  11. Specific-heat measurements on dilute 3He-4He mixtures

    International Nuclear Information System (INIS)

    Zeeuw, H.C.M. van der.

    1985-01-01

    The author measured the specific heat of dilute 3 He- 4 He mixtures in the concentration range from X = 1 x 10 -3 to X = 3 x 10 -3 and in the temperature range from 100 mK to 600 mK. This has been done by means of a thermal relaxation method. This method provides some interesting features and is applied, to our knowledge, for the first time to dilute 3 He- 4 He mixtures. To reach the required temperature range for our experiments a 4 He circulating 3 He- 4 He dilution refrigerator has been constructed. The results confirm the deviation of the 3 He contribution to the specific heat from the ideal Fermi gas behaviour. (Auth.)

  12. Theoretical Models for the Cooling Power and Base Temperature of Dilution Refrigerators

    CERN Document Server

    Wikus, Patrick

    2010-01-01

    He-3/He-4 dilution refrigerators are widely used for applications requiring continuous cooling at temperatures below approximately 300 mK. Despite of the popularity of these devices in low temperature physics, the thermodynamic relations underlying the cooling mechanism of He-3/He-4 refrigerators are very often incorrectly used. Several thermodynamic models of dilution refrigeration have been published in the past, sometimes contradicting each other. These models are reviewed and compared with each other over a range of different He-3 flow rates. In addition, a new numerical method for the calculation of a dilution refrigerator's cooling power at arbitrary flow rates is presented. This method has been developed at CERN's Central Cryogenic Laboratory. It can be extended to include many effects that cannot easily be accounted for by any of the other models, including the degradation of heat exchanger performance due to the limited number of step heat exchanger elements, which can be considerable for some design...

  13. Redox substoichiometric isotope dilution analysis of metallic arsenic for antimony

    International Nuclear Information System (INIS)

    Kambara, Tomihisa; Yoshioka, Hiroe; Suzuki, Junsuke; Shibata, Yasue.

    1979-01-01

    In 1 M HCl solution Sb(III) reacts with N-benzoyl-N-phenylhydroxylamine (BPHA) to form a complex extractable into chloroform while the extraction of Sb(V) is negligible. The redox substoichiometric isotope dilution analysis based on this reaction was applied to the determination of antimony in metallic arsenic. After the dissolution of metallic arsenic, Sb(V) was separated from As(V) by a tribenzylamine extraction from 8 M HCl solution and the extracted Sb(V) was stripped into 0.5 M NaOH solution. Thereafter, all the Sb(V) were completely reduced to Sb(III) by bubbling SO 2 gas through 3 M HCl solution. As the substoichiometric reaction, the oxidation of Sb(III) to Sb(V) by a substoichiometric amount of potassium dichromate was used, followed by separation of these species by the BPHA extraction of Sb(III). The substoichiometric oxidation of Sb(III) was found to be quantitative over HCl concentration range from 0.8 to 1.2 M. The amount of antimony was determined by isotope dilution analysis using the method of carrier amount variation. By the present method the determination of as small as 0.36 μg antimony was accomplished with a good accuracy (relative error; 5.6%) and also the method was successfully applied to the determination of antimony in arsenic samples containing known amounts of Sb(III) and in metallic arsenic. The present method gives reliable results with the good accuracy and precision. (author)

  14. A report on the aquatic dilution experiment carried out at discharge canal, KGS site

    International Nuclear Information System (INIS)

    Reji, T.K.; Nayak, P.D.; Sudhakar, J.; Ajith, T.L.; Vishnu, M.S.; Ravi, P.M.; James, J.P.; Joshi, R.M.; Naik, S.B.; Kudtharkar, A.M.; Gaonkar, S.M.; Verma, P.C.; Datta, D.; Dahiya, Sudhir; Brijkumar; Datta, Maduparna; Sajeevan, G.

    2009-08-01

    Under Nuclear Power Corporation of India Limited (NPCIL), three units of (each of capacity 220MWe) Nuclear Power Stations are operational and one unit of similar capacity is under advanced stage of construction at Kaiga site. The radioactive liquid effluents generated in the plant are diluted with Condenser Coolant Water Stream (CCW) which is then discharged into Kadra reservoir through an artificially made discharge canal. The basic objective of the present study is to estimate the Dilution Factors at various locations of discharge canal and to understand the process of dilution and dispersion of radioactive effluent in the discharge canal. The strategy of the experiment involved the collection of samples from discharge canal lengthwise, breadth wise and depth wise immediately after the routine release of one of the batches of effluent stream into the CCW stream. No additional activity was released for the purpose of this experiment. The study compared the experimentally obtained Dilution Factor with that calculated based on the flow rates of CCW pumps and active liquid effluent discharge pumps. In the present conditions of experiment, Dilution Factor, based on flow rates of CCW pumps and Liquid Effluent Discharge pump, works out to be 8.11 E -05 while experimentally observed Mean Dilution Factor in the discharge canal works out to be (7.75±2.15) E-05. Hence this experiment clearly demonstrate the validity of the method of calculating dilution factor based on the flow rates of CCW line and that of Effluent discharge pump. The data analysis indicates that mass flow seems to be the major process of dispersion in the discharge canal. The tritium activity was found to be moving faster in the midstream as compared to that near the shore. The conclusions are drawn purely based on experimental results. This experimental data can be used for validation of aquatic dispersion models. (author)

  15. Developments on drug discovery and on new therapeutics: highly diluted tinctures act as biological response modifiers

    Directory of Open Access Journals (Sweden)

    de Oliveira Carolina C

    2011-10-01

    Full Text Available Abstract Background In the search for new therapies novel drugs and medications are being discovered, developed and tested in laboratories. Highly diluted substances are intended to enhance immune system responses resulting in reduced frequency of various diseases, and often present no risk of serious side-effects due to its low toxicity. Over the past years our research group has been investigating the action of highly diluted substances and tinctures on cells from the immune system. Methods We have developed and tested several highly diluted tinctures and here we describe the biological activity of M1, M2, and M8 both in vitro in immune cells from mice and human, and in vivo in mice. Cytotoxicity, cytokines released and NF-κB activation were determined after in vitro treatment. Cell viability, oxidative response, lipid peroxidation, bone marrow and lymph node cells immunophenotyping were accessed after mice in vivo treatment. Results None of the highly diluted tinctures tested were cytotoxic to macrophages or K562. Lipopolysaccharide (LPS-stimulated macrophages treated with all highly diluted tinctures decreased tumour necrosis factor alpha (TNF-α release and M1, and M8 decreased IFN-γ production. M1 has decreased NF-κB activity on TNF-α stimulated reporter cell line. In vivo treatment lead to a decrease in reactive oxygen species (ROS, nitric oxide (NO production was increased by M1, and M8, and lipid peroxidation was induced by M1, and M2. All compounds enhanced the innate immunity, but M1 also augmented acquired immunity and M2 diminished B lymphocytes, responsible to acquired immunity. Conclusions Based on the results presented here, these highly diluted tinctures were shown to modulate immune responses. Even though further investigation is needed there is an indication that these highly diluted tinctures could be used as therapeutic interventions in disorders where the immune system is compromised.

  16. Tunnel backfill erosion by dilute water

    Energy Technology Data Exchange (ETDEWEB)

    Olin, M. [VTT Technical Research Centre of Finland, Espoo (Finland)

    2014-03-15

    The goal was to estimate smectite release from tunnel backfill due to dilute groundwater pulse during post glacial conditions. The plan was to apply VTT's two different implementations (BESW{sub D} and BESW{sub S}) of well-known model of Neretnieks et al. (2009). It appeared difficult to produce repeatable results using this model in COMSOL 4.2 environment, therefore a semi-analytical approximate approach was applied, which enabled to take into account both different geometry and smectite content in tunnel backfill as compared to buffer case. The results are quite similar to buffer results due to the decreasing effect of smaller smectite content and the increasing effect of larger radius. (orig.)

  17. Ultrafast magnetization dynamics in diluted magnetic semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Morandi, O [INRIA Nancy Grand-Est and Institut de Recherche en Mathematiques Avancees, 7 rue Rene Descartes, F-67084 Strasbourg (France); Hervieux, P-A; Manfredi, G [Institut de Physique et Chimie des Materiaux de Strasbourg, 23 rue du Loess, F-67037 Strasbourg (France)], E-mail: morandi@dipmat.univpm.it

    2009-07-15

    We present a dynamical model that successfully explains the observed time evolution of the magnetization in diluted magnetic semiconductor quantum wells after weak laser excitation. Based on the pseudo-fermion formalism and a second-order many-particle expansion of the exact p-d exchange interaction, our approach goes beyond the usual mean-field approximation. It includes both the sub-picosecond demagnetization dynamics and the slower relaxation processes that restore the initial ferromagnetic order in a nanosecond timescale. In agreement with experimental results, our numerical simulations show that, depending on the value of the initial lattice temperature, a subsequent enhancement of the total magnetization may be observed within the timescale of a few hundred picoseconds.

  18. Mechanisms of urine concentration and dilution (1961)

    International Nuclear Information System (INIS)

    Morel, F.; Guinnebault, M.

    1961-01-01

    This paper is devoted to the analysis of a problem in the field of renal physiology which has shown many new developments during the course of the last few years. The following are treated successively: a) the data obtained from measurements of free water clearance and their interpretation; b) the data provided by nephron morphology and the comparative anatomy of the kidney ; c) the data relative to the existence of an intrarenal osmotic gradient; d) the principle of concentration multiplication by a counter current technique; e) the present day theory of counter current concentration of urine, and f) the physiological check on dilution and concentration mechanisms in urine. Lastly, the advantages of the modern theory and the unknown factors which remain are discussed. (authors) [fr

  19. Tunnel backfill erosion by dilute water

    International Nuclear Information System (INIS)

    Olin, M.

    2014-03-01

    The goal was to estimate smectite release from tunnel backfill due to dilute groundwater pulse during post glacial conditions. The plan was to apply VTT's two different implementations (BESW D and BESW S ) of well-known model of Neretnieks et al. (2009). It appeared difficult to produce repeatable results using this model in COMSOL 4.2 environment, therefore a semi-analytical approximate approach was applied, which enabled to take into account both different geometry and smectite content in tunnel backfill as compared to buffer case. The results are quite similar to buffer results due to the decreasing effect of smaller smectite content and the increasing effect of larger radius. (orig.)

  20. Critical exponents for diluted resistor networks.

    Science.gov (United States)

    Stenull, O; Janssen, H K; Oerding, K

    1999-05-01

    An approach by Stephen [Phys. Rev. B 17, 4444 (1978)] is used to investigate the critical properties of randomly diluted resistor networks near the percolation threshold by means of renormalized field theory. We reformulate an existing field theory by Harris and Lubensky [Phys. Rev. B 35, 6964 (1987)]. By a decomposition of the principal Feynman diagrams, we obtain diagrams which again can be interpreted as resistor networks. This interpretation provides for an alternative way of evaluating the Feynman diagrams for random resistor networks. We calculate the resistance crossover exponent phi up to second order in epsilon=6-d, where d is the spatial dimension. Our result phi=1+epsilon/42+4epsilon(2)/3087 verifies a previous calculation by Lubensky and Wang, which itself was based on the Potts-model formulation of the random resistor network.

  1. A horizontal dilution refrigerator for polarized target

    International Nuclear Information System (INIS)

    Isagawa, S.; Ishimoto, S.; Masaike, A.; Morimoto, K.

    1978-01-01

    A horizontal dilution refrigerator was constructed with a view to the spin frozen target and the deuteron polarized target. High cooling power at high temperature such as 3.7 mW at 400 mK serves for overcoming a heat load of microwave to polarize the nuclear spins in the target material. The cooling power at 50 mK was 50 μW, which is sufficient to hold the high nuclear polarization for long time. The lowest temperature reached was 26 mK. The refrigerator has rather simple heat exchangers, a long stainless steel double tube heat exchanger and two coaxial type heat exchangers with sintered copper. The mixing chamber is made of polytetrafluoroethylene (TFE) and demountable so that the target material can be easily put into it. (Auth.)

  2. Asymptotic Distribution of Eigenvalues of Weakly Dilute Wishart Matrices

    Energy Technology Data Exchange (ETDEWEB)

    Khorunzhy, A. [Institute for Low Temperature Physics (Ukraine)], E-mail: khorunjy@ilt.kharkov.ua; Rodgers, G. J. [Brunel University, Uxbridge, Department of Mathematics and Statistics (United Kingdom)], E-mail: g.j.rodgers@brunel.ac.uk

    2000-03-15

    We study the eigenvalue distribution of large random matrices that are randomly diluted. We consider two random matrix ensembles that in the pure (nondilute) case have a limiting eigenvalue distribution with a singular component at the origin. These include the Wishart random matrix ensemble and Gaussian random matrices with correlated entries. Our results show that the singularity in the eigenvalue distribution is rather unstable under dilution and that even weak dilution destroys it.

  3. ACTIVITY OF LEAF-CUTTING ANT Atta sexdens piriventris SUBMITED TO HIGH DILUTION HOMEOPATHIC PREPARATIONS

    Directory of Open Access Journals (Sweden)

    Alexandre Giesel

    2013-02-01

    Full Text Available The effect of high dilution preparations on the movement and foraging activities of Atta sexdens piriventris was evaluated. Five colonies of ants were located on each of the five experimental areas using a randomized complete block design. Three main forage trails from each colony were selected from where evaluations were made. Ten mL of high dilution preparation of Atta sexdens piriventris nosodes and Belladonna homeopathy solution were sprayed over 0.5 m of each selected trail, 1.0 m far from the nest. The controls were pure water and non treated trails. Applications were made daily during 10 days. The total number of ants moving on each trail one meter away from the nest, carrying or not plant fragments, were assessed before the daily application. Dilution preparations at 30CH (thirtieth centesimal Hahnemannian dilution of A. sexdens piriventris nosodes and Belladonna reduced the activities of ants from the fifth day after the first application. The treatment effect lasted more than 20 days after the last application. The use of preparation at 30CH dilution order to reduce the foraging activity of leaf-cutting ants is a potential non residual method to manage leaf-cutting ants.

  4. 21 CFR 866.2500 - Microtiter diluting and dispensing device.

    Science.gov (United States)

    2010-04-01

    ... SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2500... a mechanical device intended for medical purposes to dispense or serially dilute very small...

  5. Effect of wine dilution on the reliability of tannin analysis by protein precipitation

    DEFF Research Database (Denmark)

    Jensen, Jacob Skibsted; Werge, Hans Henrik Malmborg; Egebo, Max

    2008-01-01

    A reported analytical method for tannin quantification relies on selective precipitation of tannins with bovine serum albumin. The reliability of tannin analysis by protein precipitation on wines having variable tannin levels was evaluated by measuring the tannin concentration of various dilutions...... of five commercial red wines. Tannin concentrations of both very diluted and concentrated samples were systematically underestimated, which could be explained by a precipitation threshold and insufficient protein for precipitation, respectively. Based on these findings, we have defined a valid range...... of the tannin response in the protein precipitation-tannin assay, which suffers minimally from these problems....

  6. High-throughput ab-initio dilute solute diffusion database.

    Science.gov (United States)

    Wu, Henry; Mayeshiba, Tam; Morgan, Dane

    2016-07-19

    We demonstrate automated generation of diffusion databases from high-throughput density functional theory (DFT) calculations. A total of more than 230 dilute solute diffusion systems in Mg, Al, Cu, Ni, Pd, and Pt host lattices have been determined using multi-frequency diffusion models. We apply a correction method for solute diffusion in alloys using experimental and simulated values of host self-diffusivity. We find good agreement with experimental solute diffusion data, obtaining a weighted activation barrier RMS error of 0.176 eV when excluding magnetic solutes in non-magnetic alloys. The compiled database is the largest collection of consistently calculated ab-initio solute diffusion data in the world.

  7. Dielectric relaxation studies of dilute solutions of amides

    Energy Technology Data Exchange (ETDEWEB)

    Malathi, M.; Sabesan, R.; Krishnan, S

    2003-11-15

    The dielectric constants and dielectric losses of formamide, acetamide, N-methyl acetamide, acetanilide and N,N-dimethyl acetamide in dilute solutions of 1,4-dioxan/benzene have been measured at 308 K using 9.37 GHz, dielectric relaxation set up. The relaxation time for the over all rotation {tau}{sub (1)} and that for the group rotation {tau}{sub (2)} of (the molecules were determined using Higasi's method. The activation energies for the processes of dielectric relaxation and viscous flow were determined by using Eyring's rate theory. From relaxation time behaviour of amides in non-polar solvent, solute-solvent and solute-solute type of molecular association is proposed.

  8. A field survey of metal binding to metallothionein and other cytosolic ligands in liver of eels using an on-line isotope dilution method in combination with size exclusion (SE) high pressure liquid chromatography (HPLC) coupled to Inductively Coupled Plasma time-of-flight Mass Spectrometry (ICP-TOFMS).

    Science.gov (United States)

    Van Campenhout, Karen; Goenaga Infante, Heidi; Goemans, Geert; Belpaire, Claude; Adams, Freddy; Blust, Ronny; Bervoets, Lieven

    2008-05-15

    The effect of metal exposure on the accumulation and cytosolic speciation of metals in livers of wild populations of European eel with special emphasis on metallothioneins (MT) was studied. Four sampling sites in Flanders showing different degrees of heavy metal contamination were selected for this purpose. An on-line isotope dilution method in combination with size exclusion (SE) high pressure liquid chromatography (HPLC) coupled to Inductively Coupled Plasma time-of-flight Mass Spectrometry (ICP-TOFMS) was used to study the cytosolic speciation of the metals. The distribution of the metals Cd, Cu, Ni, Pb and Zn among cytosolic fractions displayed strong differences. The cytosolic concentration of Cd, Ni and Pb increased proportionally with the total liver levels. However, the cytosolic concentrations of Cu and Zn only increased above a certain liver tissue threshold level. Cd, Cu and Zn, but not Pb and Ni, were largely associated with the MT pool in correspondence with the environmental exposure and liver tissue concentrations. Most of the Pb and Ni and a considerable fraction of Cu and Zn, but not Cd, were associated to High Molecular Weight (HMW) fractions. The relative importance of the Cu and Zn in the HMW fraction decreased with increasing contamination levels while the MT pool became progressively more important. The close relationship between the cytosolic metal load and the total MT levels or the metals bound on the MT pool indicates that the metals, rather than other stress factors, are the major factor determining MT induction.

  9. Quantitation of 4-Methyl-4-sulfanylpentan-2-one (4MSP) in Hops by a Stable Isotope Dilution Assay in Combination with GC×GC-TOFMS: Method Development and Application To Study the Influence of Variety, Provenance, Harvest Year, and Processing on 4MSP Concentrations.

    Science.gov (United States)

    Reglitz, Klaas; Steinhaus, Martin

    2017-03-22

    A stable isotope dilution assay was developed for quantitation of 4-methyl-4-sulfanylpentan-2-one (4MSP) in hops. The approach included the use of 4-( 13 C)methyl-4-sulfanyl(1,3,5- 13 C 3 )pentan-2-one as internal standard, selective isolation of hop thiols by mercurated agarose, and GC×GC-TOFMS analysis. Application of the method to 53 different hop samples revealed 4MSP concentrations between <1 and 114 μg/kg. Notably high concentrations were associated with United States varieties such as Citra, Eureka, Simcoe, and Apollo, whereas 4MSP was absent from traditional German and English varieties. Further experiments showed that besides the variety, also harvest year and storage vitally influenced 4MSP concentrations, whereas the impact of provenance was less pronounced. Hop processing such as drying and pelletizing had only a minor impact on 4MSP concentrations. Like the majority of other hop volatiles, 4MSP is predominantly located in the lupulin glands.

  10. Development of an ultratrace analysis method for elements of the platinum group contained in environmental and geological samples using an ICP-QMS with isotope dilution analysis and suitable separation techniques; Entwicklung eines Verfahrens zur Ultraspurenbestimmung der Platingruppenelemente in Umwelt- und geologischen Proben mit einem ICP-QMS unter Verwendung der Isotopenverduennungsanalyse sowie geeigneter Separationstechniken

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, M.

    2001-07-01

    This study focussed on developing a method of ultratrace analysis for elements of the platinum group contained in environmental or geological samples using mass spectroscopic isotope dilution analysis followed by measurement on a quadrupol ICP-MS (ICP-QMSIVA). This method was subsequently used for the certification of two reference materials for environmental sampling as part of a EU project titled ''Production and certification of a road dust reference material for platinum, palladium and rhodium (PGEs) in automotive catalytic converters (PACEPAC)''. In the intercomparison round the results obtained were found to be in very good agreement with the weighted mean values of the results obtained by the other participating laboratories. The results obtained with the method developed in this study were used for the preliminary certification procedure across all elements under study without exception. In this way the present study made a substantial contribution to the successful completion of this project, and prior expectations concerning the correctness and consistency of the developed method were satisfied to the full. This is renewed confirmation of the great significance of the isotope dilution technique for the certification of reference materials, which is attributable to the highly accurate results it yields when handled properly. Comparison between CNiS dokimasia and NAA on the one hand, which was carried out in cooperation with the Nuclear Chemical Institute of Mainz University, and the present method on the other showed good agreement in terms of the decrease in Pd and Pt concentrations with growing distance from the motorway. In conjunction with the research results obtained with NAA, a well-established technique, this study shows that elements of the platinum group from automotive catalytic converters are largely emitted in metallic form. ICP-QMSIVA thus represents a very good means of keeping track of the anthropogenic deposition in the

  11. Weighted Geometric Dilution of Precision Calculations with Matrix Multiplication

    Directory of Open Access Journals (Sweden)

    Chien-Sheng Chen

    2015-01-01

    Full Text Available To enhance the performance of location estimation in wireless positioning systems, the geometric dilution of precision (GDOP is widely used as a criterion for selecting measurement units. Since GDOP represents the geometric effect on the relationship between measurement error and positioning determination error, the smallest GDOP of the measurement unit subset is usually chosen for positioning. The conventional GDOP calculation using matrix inversion method requires many operations. Because more and more measurement units can be chosen nowadays, an efficient calculation should be designed to decrease the complexity. Since the performance of each measurement unit is different, the weighted GDOP (WGDOP, instead of GDOP, is used to select the measurement units to improve the accuracy of location. To calculate WGDOP effectively and efficiently, the closed-form solution for WGDOP calculation is proposed when more than four measurements are available. In this paper, an efficient WGDOP calculation method applying matrix multiplication that is easy for hardware implementation is proposed. In addition, the proposed method can be used when more than exactly four measurements are available. Even when using all-in-view method for positioning, the proposed method still can reduce the computational overhead. The proposed WGDOP methods with less computation are compatible with global positioning system (GPS, wireless sensor networks (WSN and cellular communication systems.

  12. Decomposition of dilute residual active chlorine in sea-water

    International Nuclear Information System (INIS)

    Yoshinaga, Tetsutaro; Kawano, Kentaro; Yanagase, Kenjiro; Shiga, Akira

    1985-01-01

    Coastal industries such as power stations require enormous quantities of sea-water for cooling, but the marine organisms in it often result in fouling and/or blockade of the circulating water condenser and pipeworks. To prevent this, chlorine, or hypochlorite by the direct electrolysis of sea-water have been added. Environmental concerns, however, dictate that the residual chlorine concentration at the outlet should be less than the regulated value (0.02 ppm). Methods for decomposing dilute residual chlorine solutions were therefore studied. It was found that: 1) The addition of (raw) sea-water to the sea-water which passed through the condenser lowered the residual chlorine concentration to an greater extent than could be expected by dilution only. 2) Ozonation of the residual chlorine solution led to degradation of OCl - , but in solutions with a residual chlorine concentrations of less than 3 -- 4 ppm, ozonation had no effect. 3) Irradiation with ultra violet light (254 nm) decomposed the residual chlorine. Under the present work conditions (25 0 C: pH 8; depth 10 mm), nearly first order kinetics were to hold [da/dt = ksub((1)) (1-a)sup(n)]. There is a proportional relationship between the kinetic constant (k) and illuminous intensity (L), i.e., ksub((1))[C 0 sup(Cl 2 ): 10 ppm] = 6.56 x 10 -5 L (L = 0 -- 1000 lx). Thus, the use of both sea-water addition and UV irradiation provides a probable method for decomposing a residual chlorine to the expected concentration. (author)

  13. An Isotopic Dilution Experiment Using Liquid Scintillation: A Simple Two-System, Two-Phase Analysis.

    Science.gov (United States)

    Moehs, Peter J.; Levine, Samuel

    1982-01-01

    A simple isotonic, dilution analysis whose principles apply to methods of more complex radioanalyses is described. Suitable for clinical and instrumental analysis chemistry students, experimental manipulations are kept to a minimum involving only aqueous extraction before counting. Background information, procedures, and results are discussed.…

  14. Identification of ultrasound-contrast-agent dilution systems for ejection fraction measurements

    NARCIS (Netherlands)

    Mischi, M.; Jansen, A.H.M.; Kalker, A.A.C.M.; Korsten, H.H.M.

    2005-01-01

    Left ventricular ejection fraction is an important cardiac-efficiency measure. Standard estimations are based on geometric analysis and modeling; they require time and experienced cardiologists. Alternative methods make use of indicator dilutions, but they are invasive due to the need for

  15. Comparison of bile acid synthesis determined by isotope dilution versus fecal acidic sterol output in human subjects

    International Nuclear Information System (INIS)

    Duane, W.C.; Holloway, D.E.; Hutton, S.W.; Corcoran, P.J.; Haas, N.A.

    1982-01-01

    Fecal acidic sterol output has been found to be much lower than bile acid synthesis determined by isotope dilution. Because of this confusing discrepancy, we compared these 2 measurements done simultaneously on 13 occasions in 5 normal volunteers. In contrast to previous findings, bile acid synthesis by the Lindstedt isotope dilution method averaged 16.3% lower than synthesis simultaneously determined by fecal acidic sterol output (95% confidence limit for the difference - 22.2 to -10.4%). When one-sample determinations of bile acid pools were substituted for Lindstedt pools, bile acid synthesis by isotope dilution averaged 5.6% higher than synthesis by fecal acidic sterol output (95% confidence limits -4.9 to 16.1%). These data indicate that the 2 methods yield values in reasonably close agreement with one another. If anything, fecal acidic sterol outputs are slightly higher than synthesis by isotope dilution

  16. Comparison of in vitro activity of five antifungal agents against dermatophytes, using the agar dilution and broth microdilution methods Comparação da atividade in vitro de cinco agentes antifúngicos para dermatófitos, usando os métodos de diluição em ágar e microdiluição em caldo

    Directory of Open Access Journals (Sweden)

    Crystiane Rodrigues Araújo Mota

    2009-06-01

    Full Text Available The purpose of this study was to compare the agar dilution and broth microdilution methods for determining the minimum inhibitory concentration (MIC of fluconazole, itraconazole, ketoconazole, griseofulvin and terbinafine for 60 dermatophyte samples belonging to the species Trichophyton rubrum, Trichophyton mentagrophytes and Microsporum canis. The percentage agreement between the two methods, for all the isolates with O propósito do presente trabalho foi comparar os métodos de diluição em ágar e diluição em caldo para a determinação de concentração inibitória mínima de fluconazol, itraconazol, cetoconazol, griseofulvina e terbinafina para 60 amostras de dermatófitos pertencentes às espécies, Trichophyton rubrum, Trichophyton. mentagrophytes e Microsporum canis. A porcentagem de acordo entre os dois métodos para todos os isolados testados considerando-se valores < 2 diluições, foram de 91,6% para cetoconazol e para griseofulvina, de 88,3% para itraconazol, de 81,6% para terbinafina e de 73,3% para fluconazol. Uma concordância de 100% foi obtido para isolados de Trichophyton mentagrophytes avaliados com cetoconazol e griseofulvina. Desta forma, até que um método de referência seja padronizado para testar a suscetibilidade in vitro para os dermatófitos, os resultados semelhantes encontrados para os dois métodos fazem com que o método de diluição em ágar possa ser útil no teste de suscetibilidade para estes fungos filamentosos.

  17. Behaviour of humic-bentonite aggregates in diluted suspensions ...

    African Journals Online (AJOL)

    Formation and disaggregation of micron-size aggregates in a diluted suspension made up of HSs and bentonite (B) were studied by tracing distribution of aggregate sizes and their counts in freshly prepared and aged suspensions, and at high (10 000) and low (1.0) [HS]/[B] ratios. Diluted HSB suspensions are unstable ...

  18. Dilution in Transition Zone between Rising Plumes and Surface Plumes

    DEFF Research Database (Denmark)

    Larsen, Torben

    2004-01-01

    The papers presents some physical experiments with the dilution of sea outfall plumes with emphasize on the transition zone where the relative fast flowing vertical plume turns to a horizontal surface plume following the slow sea surface currents. The experiments show that a considerable dilution...

  19. Magnetic ordering in dilute YTb and YEr alloys

    International Nuclear Information System (INIS)

    Rainford, B.D.; Kilcoyne, S.H.; Mohammed, K.A.; Lanchester, P.C.; Stanley, H.B.; Caudron, R.

    1988-01-01

    Dilute YEr alloys (Er concentration between 3% and 10%) show the existence of sinusoidally modulated antiferromagnetism down to the lowest impurity concentrations studied. Extrapolation of the Neel temperatures for both YEr and YTb suggests a critical concentration is ≅ 0.8% Tb, Er. Ordering in such dilute alloys may result from exchange enhancement in the yttrium host

  20. Magnetic ordering in dilute YTb and YEr alloys

    Energy Technology Data Exchange (ETDEWEB)

    Rainford, B.D.; Kilcoyne, S.H.; Mohammed, K.A.; Lanchester, P.C.; Stanley, H.B.; Caudron, R.

    1988-12-01

    Dilute YEr alloys (Er concentration between 3% and 10%) show the existence of sinusoidally modulated antiferromagnetism down to the lowest impurity concentrations studied. Extrapolation of the Neel temperatures for both YEr and YTb suggests a critical concentration is /approx equal/ 0.8% Tb, Er. Ordering in such dilute alloys may result from exchange enhancement in the yttrium host.

  1. Near-wall molecular ordering of dilute ionic liquids

    NARCIS (Netherlands)

    Jitvisate, Monchai; Seddon, James Richard Thorley

    2017-01-01

    The interfacial behavior of ionic liquids promises tunable lubrication as well as playing an integral role in ion diffusion for electron transfer. Diluting the ionic liquids optimizes bulk parameters, such as electric conductivity, and one would expect dilution to disrupt the near-wall molecular

  2. Effect of dietary dilution of energy and nutrients during different ...

    African Journals Online (AJOL)

    A completely randomized design was conducted to evaluate the effect of dietary dilution of energy and nutrients during different growing periods on compensatory growth of Ross broilers. Four replicant pens were assigned per seven treatments. Chicks in each treatment received concentrated and diluted diets in different ...

  3. The dilute random field Ising model by finite cluster approximation

    International Nuclear Information System (INIS)

    Benyoussef, A.; Saber, M.

    1987-09-01

    Using the finite cluster approximation, phase diagrams of bond and site diluted three-dimensional simple cubic Ising models with a random field have been determined. The resulting phase diagrams have the same general features for both bond and site dilution. (author). 7 refs, 4 figs

  4. Enhancement of surface magnetism due to bulk bond dilution

    International Nuclear Information System (INIS)

    Tsallis, C.; Sarmento, E.F.; Albuquerque, E.L. de

    1985-01-01

    Within a renormalization group scheme, the phase diagram of a semi-infinite simple cubic Ising ferromagnet is discussed, with arbitrary surface and bulk coupling constants, and including possible dilution of the bulk bonds. It is obtained that dilution makes easier the appearance of surface magnetism in the absence of bulk magnetism. (Author) [pt

  5. Estimation of the volatility distribution of organic aerosol combining thermodenuder and isothermal dilution measurements

    Science.gov (United States)

    Louvaris, Evangelos E.; Karnezi, Eleni; Kostenidou, Evangelia; Kaltsonoudis, Christos; Pandis, Spyros N.

    2017-10-01

    A method is developed following the work of Grieshop et al. (2009) for the determination of the organic aerosol (OA) volatility distribution combining thermodenuder (TD) and isothermal dilution measurements. The approach was tested in experiments that were conducted in a smog chamber using organic aerosol (OA) produced during meat charbroiling. A TD was operated at temperatures ranging from 25 to 250 °C with a 14 s centerline residence time coupled to a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) and a scanning mobility particle sizer (SMPS). In parallel, a dilution chamber filled with clean air was used to dilute isothermally the aerosol of the larger chamber by approximately a factor of 10. The OA mass fraction remaining was measured as a function of temperature in the TD and as a function of time in the isothermal dilution chamber. These two sets of measurements were used together to estimate the volatility distribution of the OA and its effective vaporization enthalpy and accommodation coefficient. In the isothermal dilution experiments approximately 20 % of the OA evaporated within 15 min. Almost all the OA evaporated in the TD at approximately 200 °C. The resulting volatility distributions suggested that around 60-75 % of the cooking OA (COA) at concentrations around 500 µg m-3 consisted of low-volatility organic compounds (LVOCs), 20-30 % of semivolatile organic compounds (SVOCs), and around 10 % of intermediate-volatility organic compounds (IVOCs). The estimated effective vaporization enthalpy of COA was 100 ± 20 kJ mol-1 and the effective accommodation coefficient was 0.06-0.07. Addition of the dilution measurements to the TD data results in a lower uncertainty of the estimated vaporization enthalpy as well as the SVOC content of the OA.

  6. Estimation of the volatility distribution of organic aerosol combining thermodenuder and isothermal dilution measurements

    Directory of Open Access Journals (Sweden)

    E. E. Louvaris

    2017-10-01

    Full Text Available A method is developed following the work of Grieshop et al. (2009 for the determination of the organic aerosol (OA volatility distribution combining thermodenuder (TD and isothermal dilution measurements. The approach was tested in experiments that were conducted in a smog chamber using organic aerosol (OA produced during meat charbroiling. A TD was operated at temperatures ranging from 25 to 250 °C with a 14 s centerline residence time coupled to a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS and a scanning mobility particle sizer (SMPS. In parallel, a dilution chamber filled with clean air was used to dilute isothermally the aerosol of the larger chamber by approximately a factor of 10. The OA mass fraction remaining was measured as a function of temperature in the TD and as a function of time in the isothermal dilution chamber. These two sets of measurements were used together to estimate the volatility distribution of the OA and its effective vaporization enthalpy and accommodation coefficient. In the isothermal dilution experiments approximately 20 % of the OA evaporated within 15 min. Almost all the OA evaporated in the TD at approximately 200 °C. The resulting volatility distributions suggested that around 60–75 % of the cooking OA (COA at concentrations around 500 µg m−3 consisted of low-volatility organic compounds (LVOCs, 20–30 % of semivolatile organic compounds (SVOCs, and around 10 % of intermediate-volatility organic compounds (IVOCs. The estimated effective vaporization enthalpy of COA was 100 ± 20 kJ mol−1 and the effective accommodation coefficient was 0.06–0.07. Addition of the dilution measurements to the TD data results in a lower uncertainty of the estimated vaporization enthalpy as well as the SVOC content of the OA.

  7. Dynamic dilution exponent in monodisperse entangled polymer solutions

    DEFF Research Database (Denmark)

    Shahid, T.; Huang, Qian; Oosterlinck, F.

    2017-01-01

    of concentration but also depends on the molar mass of the chains. While the proposed approach successfully explains the viscoelastic properties of a large number of semi-dilute solutions of polymers in their own oligomers, important discrepancies are found for semi-dilute entangled polymers in small-molecule......We study and model the linear viscoelastic properties of several entangled semi-dilute and concentrated solutions of linear chains of different molar masses and at different concentrations dissolved in their oligomers. We discuss the dilution effect of the oligomers on the entangled long chains....... In particular, we investigate the influence of both concentration and molar mass on the value of the effective dynamic dilution exponent determined from the level of the storage plateau at low and intermediate frequencies. We show that the experimental results can be quantitatively explained by considering...

  8. The dilution effect on the extinction of wall diffusion flame

    Directory of Open Access Journals (Sweden)

    Ghiti Nadjib

    2014-12-01

    Full Text Available The dynamic process of the interaction between a turbulent jet diffusion methane flame and a lateral wall was experimentally studied. The evolution of the flame temperature field with the Nitrogen dilution of the methane jet flame was examined. The interaction between the diffusion flame and the lateral wall was investigated for different distance between the wall and the central axes of the jet flame. The dilution is found to play the central role in the flame extinction process. The flame response as the lateral wall approaches from infinity and the increasing of the dilution rate make the flame extinction more rapid than the flame without dilution, when the nitrogen dilution rate increase the flame temperature decrease.

  9. Accurate determination and certification of bromine in plastic by isotope dilution inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Ohata, Masaki, E-mail: m-oohata@aist.go.jp; Miura, Tsutomu

    2014-07-21

    Highlights: • Accurate analytical method of Br in plastic was studied by isotope dilution ICPMS. • A microwave acid digestion using quartz vessel was suitable for Br analysis. • Sample dilution by NH{sub 3} solution could remove memory effect for ICPMS measurement. • The analytical result of the ID-ICPMS showed consistency with that of INAA. • The ID-ICPMS developed could apply to certification of Br in candidate plastic CRM. - Abstract: The accurate analytical method of bromine (Br) in plastic was developed by an isotope dilution inductively coupled plasma mass spectrometry (ID-ICPMS). The figures of merit of microwave acid digestion procedures using polytetrafluoroethylene (PTFE) or quartz vessels were studied and the latter one was suitable for Br analysis since its material was free from Br contamination. The sample dilution procedures using Milli-Q water or ammonium (NH{sub 3}) solution were also studied to remove memory effect for ICPMS measurement. Although severe memory effect was observed on Milli-Q water dilution, NH{sub 3} solution could remove it successfully. The accuracy of the ID-ICPMS was validated by a certified reference material (CRM) as well as the comparison with the analytical result obtained by an instrumental neutron activation analysis (INAA) as different analytical method. From these results, the ID-ICPMS developed in the present study could be evaluated as accurate analytical method of Br in plastic materials and it could apply to certification of Br in candidate plastic CRM with respect to such regulations related to RoHS (restriction of the use of hazardous substances in electrical and electronics equipment) directive.

  10. Accurate determination and certification of bromine in plastic by isotope dilution inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Ohata, Masaki; Miura, Tsutomu

    2014-01-01

    Highlights: • Accurate analytical method of Br in plastic was studied by isotope dilution ICPMS. • A microwave acid digestion using quartz vessel was suitable for Br analysis. • Sample dilution by NH 3 solution could remove memory effect for ICPMS measurement. • The analytical result of the ID-ICPMS showed consistency with that of INAA. • The ID-ICPMS developed could apply to certification of Br in candidate plastic CRM. - Abstract: The accurate analytical method of bromine (Br) in plastic was developed by an isotope dilution inductively coupled plasma mass spectrometry (ID-ICPMS). The figures of merit of microwave acid digestion procedures using polytetrafluoroethylene (PTFE) or quartz vessels were studied and the latter one was suitable for Br analysis since its material was free from Br contamination. The sample dilution procedures using Milli-Q water or ammonium (NH 3 ) solution were also studied to remove memory effect for ICPMS measurement. Although severe memory effect was observed on Milli-Q water dilution, NH 3 solution could remove it successfully. The accuracy of the ID-ICPMS was validated by a certified reference material (CRM) as well as the comparison with the analytical result obtained by an instrumental neutron activation analysis (INAA) as different analytical method. From these results, the ID-ICPMS developed in the present study could be evaluated as accurate analytical method of Br in plastic materials and it could apply to certification of Br in candidate plastic CRM with respect to such regulations related to RoHS (restriction of the use of hazardous substances in electrical and electronics equipment) directive

  11. Dilute Oxygen Combustion Phase I Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, H.M.; Riley, M.F.; Kobayashi, H.

    1997-10-31

    A novel burner, in which fuel (natural gas) and oxidant (oxygen or air) are separately injected into a furnace, shows promise for achieving very low nitrogen oxide(s) (NOx) emissions for commercial furnace applications. The dilute oxygen combustion (DOC) burner achieves very low NOx through in-furnace dilution of the oxidant stream prior to combustion, resulting in low flame temperatures, thus inhibiting thermal NOx production. The results of a fundamental and applied research effort on the development of the DOC burner are presented. In addition, the results of a market survey detailing the potential commercial impact of the DOC system are disclosed. The fundamental aspects of the burner development project involved examining the flame characteristics of a natural gas turbulent jet in a high-temperature (~1366 K) oxidant (7-27% O2 vol. wet). Specifically, the mass entrainment rate, the flame lift-off height, the velocity field and major species field of the jet were evaluated as a function of surrounding-gas temperature and composition. The measured entrainment rate of the fuel jet decreased with increasing oxygen content in the surrounding high-temperature oxidant, and was well represented by the d+ scaling correlation found in the literature. The measured flame lift-off height decreased with increasing oxygen content and increasing temperature of the surrounding gas. An increase in surrounding-gas oxygen content and/or temperature inhibited the velocity decay within the jet periphery as a function of axial distance as compared to isothermal turbulent jets. However, the velocity measurements were only broadly represented by the d+ scaling correlation. Several DOC burner configurations were tested in a laboratory-scale furnace at a nominal firing rate of 185 kW (~0.63 MMBtu/h). The flue gas composition was recorded as a function of furnace nitrogen content, furnace temperature, burner geometric arrangement, firing rate, and fuel injection velocity. NOx emissions

  12. Dilute oxygen combustion. Phase I report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-10-01

    A novel burner, in which fuel (natural gas) and oxidant (oxygen or air) are separately injected into a furnace, shows promise for achieving very low nitrogen oxide(s) (NO{sub x}) emissions for commercial furnace applications. The dilute oxygen combustion (DOC) burner achieves very low NO{sub x} through in-furnace dilution of the oxidant stream prior to combustion, resulting in low flame temperatures, thus inhibiting thermal NO{sub x} production. The results of a fundamental and applied research effort on the development of the DOC burner are presented. In addition, the results of a market survey detailing the potential commercial impact of the DOC system are disclosed. The fundamental aspects of the burner development project involved examining the flame characteristics of a natural gas turbulent jet in a high-temperature ({approximately}1366 K) oxidant (7-27% O{sub 2} vol. wet). Specifically, the mass entrainment rate, the flame lift-off height, the velocity field and major species field of the jet were evaluated as a function of surrounding-gas temperature and composition. The measured entrainment rate of the fuel jet decreased with increasing oxygen content in the surrounding high-temperature oxidant, and was well represented by the d{sup +} scaling correlation found in the literature. The measured flame lift-off height decreased with increasing oxygen content and increasing temperature of the surrounding gas. An increase in surrounding-gas oxygen content and/or temperature inhibited the velocity decay within the jet periphery as a function of axial distance as compared to isothermal turbulent jets. However, the velocity measurements were only broadly represented by the d{sup +} scaling correlation. Several DOC burner configurations were tested in a laboratory-scale furnace at a nominal firing rate of 185 kW ({approximately}0.63 MMBtu/h). The flue gas composition was recorded as a function of furnace nitrogen content, furnace temperature, burner geometric

  13. Role reductants in dilute chemical decontamination formulations

    Energy Technology Data Exchange (ETDEWEB)

    Ranganathan, S. [Univ. of New Brunswick (Canada). Dept. of Chemical Engineering; Srinivasan, M.P.; Narasimhan, S.V. [Bhabha Atomic Research Centre (BARC), Trombay, Mumbai (India). Water and Steam Chemistry Lab.; Raghavan, P.S. [Madras Christian Coll., Chennai (India); Gopalan, R. [Madras Christian Coll., Chennai (India). Dept. of Chemistry

    2004-10-01

    Iron(III) oxides are the major corrosion products formed in boiling water reactors. The iron(III) oxides are of two types, namely hematite ({alpha}-Fe{sub 2}O{sub 3}) and maghemite ({gamma}-Fe{sub 2}O{sub 3}). The dissolution of these oxides is in no way simple because of the labile nature of the Fe(III)-O bond towards the chelants. The leaching of metal ions is partially controlled by reductive dissolution. In order to understand the role of the reductant, it is essential to study the dissolution behaviour of a system like Fe{sub 2}O{sub 3}, which does not contain any Fe{sup 2+} in the crystal lattice. The present study was carried out with {gamma}-Fe{sub 2}O{sub 3} and dilute chemical decontamination (DCD) formulations containing ascorbic acid and citric acid with the addition of Fe(II)-L as a reductant. The chelants used for the dissolution process were nitrilotriacetic acid, 2,6-pyridinedicorboxylic acid and ethylenediaminetetraacetic acid. The {gamma}-Fe{sub 2}O{sub 3} was chosen since the earlier studies revealed that the dissolution kinetics of {alpha}-Fe{sub 2}O{sub 3} is slow and it is difficult to dissolve even by strong complexing agents, whereas {gamma}-Fe{sub 2}O{sub 3} dissolution is comparatively easier. This is due to the structural difference between these two oxides. The studies also revealed that the dissolution was partly influenced by the nature of the chelating agents but mainly controlled by the power of the reductants used in the formulation. The dissolution behaviour of {gamma}-Fe{sub 2}O{sub 3} under various experimental conditions is discussed and compared with that of magnetite in order to arrive at a suitable mechanism for the dissolution of iron oxides and emphasize the role of reductants in DCD formulations. (orig.)

  14. Ionic liquids behave as dilute electrolyte solutions

    Science.gov (United States)

    Gebbie, Matthew A.; Valtiner, Markus; Banquy, Xavier; Fox, Eric T.; Henderson, Wesley A.; Israelachvili, Jacob N.

    2013-01-01

    We combine direct surface force measurements with thermodynamic arguments to demonstrate that pure ionic liquids are expected to behave as dilute weak electrolyte solutions, with typical effective dissociated ion concentrations of less than 0.1% at room temperature. We performed equilibrium force–distance measurements across the common ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C4mim][NTf2]) using a surface forces apparatus with in situ electrochemical control and quantitatively modeled these measurements using the van der Waals and electrostatic double-layer forces of the Derjaguin–Landau–Verwey–Overbeek theory with an additive repulsive steric (entropic) ion–surface binding force. Our results indicate that ionic liquids screen charged surfaces through the formation of both bound (Stern) and diffuse electric double layers, where the diffuse double layer is comprised of effectively dissociated ionic liquid ions. Additionally, we used the energetics of thermally dissociating ions in a dielectric medium to quantitatively predict the equilibrium for the effective dissociation reaction of [C4mim][NTf2] ions, in excellent agreement with the measured Debye length. Our results clearly demonstrate that, outside of the bound double layer, most of the ions in [C4mim][NTf2] are not effectively dissociated and thus do not contribute to electrostatic screening. We also provide a general, molecular-scale framework for designing ionic liquids with significantly increased dissociated charge densities via judiciously balancing ion pair interactions with bulk dielectric properties. Our results clear up several inconsistencies that have hampered scientific progress in this important area and guide the rational design of unique, high–free-ion density ionic liquids and ionic liquid blends. PMID:23716690

  15. Gas Leak Detection by Dilution of Atmospheric Oxygen

    Directory of Open Access Journals (Sweden)

    Armin Lambrecht

    2017-12-01

    Full Text Available Gas leak detection is an important issue in infrastructure monitoring and industrial production. In this context, infrared (IR absorption spectroscopy is a major measurement method. It can be applied in an extractive or remote detection scheme. Tunable laser spectroscopy (TLS instruments are able to detect CH4 leaks with column densities below 10 ppm·m from a distance of 30 m in less than a second. However, leak detection of non-IR absorbing gases such as N2 is not possible in this manner. Due to the fact that any leaking gas displaces or dilutes the surrounding background gas, an indirect detection is still possible. It is shown by sensitive TLS measurements of the ambient background concentration of O2 that N2 leaks can be localized with extractive and standoff methods for distances below 1 m. Minimum leak rates of 0.1 mbar·L/s were determined. Flow simulations confirm that the leakage gas typically effuses in a narrow jet. The sensitivity is mainly determined by ambient flow conditions. Compared to TLS detection of CH4 at 1651 nm, the indirect method using O2 at 761 nm is experimentally found to be less sensitive by a factor of 100. However, the well-established TLS of O2 may become a universal tool for rapid leakage screening of vessels that contain unknown or inexpensive gases, such as N2.

  16. Use of diluted urine for cultivation of Chlorella vulgaris.

    Science.gov (United States)

    Jaatinen, Sanna; Lakaniemi, Aino-Maija; Rintala, Jukka

    2016-01-01

    Our aim was to study the biomass growth of microalga Chlorella vulgaris using diluted human urine as a sole nutrient source. Batch cultivations (21 days) were conducted in five different urine dilutions (1:25-1:300), in 1:100-diluted urine as such and with added trace elements, and as a reference, in artificial growth medium. The highest biomass density was obtained in 1:100-diluted urine with and without additional trace elements (0.73 and 0.60 g L(-1), respectively). Similar biomass growth trends and densities were obtained with 1:25- and 1:300-diluted urine (0.52 vs. 0.48 gVSS L(-1)) indicating that urine at dilution 1:25 can be used to cultivate microalgal based biomass. Interestingly, even 1:300-diluted urine contained sufficiently nutrients and trace elements to support biomass growth. Biomass production was similar despite pH-variation from < 5 to 9 in different incubations indicating robustness of the biomass growth. Ammonium formation did not inhibit overall biomass growth. At the beginning of cultivation, the majority of the biomass consisted of living algal cells, while towards the end, their share decreased and the estimated share of bacteria and cell debris increased.

  17. The separation and determination of fatty acids by isotopic dilution and radiogas-liquid chromatography

    International Nuclear Information System (INIS)

    Beardsley, D.A.

    1981-01-01

    A number of static phases have been evaluated for the GLC separation of fatty acids. Of those investigated, only AT 1200 was capable of resolving the isomeric forms of the acids. A radiogas-liquid chromatographic method incorporating isotopic dilution analysis has been developed for the determination of n-butyric acid. The proposed method has been applied to the determination of the acid in hydrolysed butter fat and milk chocolate extracts. (author)

  18. Dilution thermodynamics of the biologically relevant cation mixtures

    International Nuclear Information System (INIS)

    Kaczyński, Marek; Borowik, Tomasz; Przybyło, Magda; Langner, Marek

    2014-01-01

    Graphical abstract: - Highlights: • Dilution energetics of Ca 2+ can be altered by the aqueous phase ionic composition. • Dissipated heat upon Ca 2+ dilution is drastically reduced in the K + presence. • Reduction of the enthalpy change upon Ca 2+ dilution is K + concentration dependent. • The cooperativity of Ca 2+ hydration might be of great biological relevance providing a thermodynamic argument for the specific ionic composition of the intracellular environment. - Abstract: The ionic composition of intracellular space is rigorously controlled by a variety of processes consuming large quantities of energy. Since the energetic efficiency is an important evolutional criterion, therefore the ion fluxes within the cell should be optimized with respect to the accompanying energy consumption. In the paper we present the experimental evidence that the dilution enthalpies of the biologically relevant ions; i.e. calcium and magnesium depend on the presence of monovalent cations; i.e. sodium and potassium. The heat flow generated during the dilution of ionic mixtures was measured with the isothermal titration calorimetry. When calcium was diluted together with potassium the dilution enthalpy was drastically reduced as the function of the potassium concentration present in the solution. No such effect was observed when the potassium ions were substituted with sodium ones. When the dilution of magnesium was investigated the dependence of the dilution enthalpy on the accompanying monovalent cation was much weaker. In order to interpret experimental evidences the ionic cluster formation is postulated. The specific organization of such cluster should depend on ions charges, sizes and organization of the hydration layers

  19. Specific heat in diluted magnetic semiconductor quantum ring

    Science.gov (United States)

    Babanlı, A. M.; Ibragimov, B. G.

    2017-11-01

    In the present paper, we have calculated the specific heat and magnetization of a quantum ring of a diluted magnetic semiconductor (DMS) material in the presence of magnetic field. We take into account the effect of Rashba spin-orbital interaction, the exchange interaction and the Zeeman term on the specific heat. We have calculated the energy spectrum of the electrons in diluted magnetic semiconductor quantum ring. Moreover we have calculated the specific heat dependency on the magnetic field and Mn concentration at finite temperature of a diluted magnetic semiconductor quantum ring.

  20. On the Wigner law in dilute random matrices

    Science.gov (United States)

    Khorunzhy, A.; Rodgers, G. J.

    1998-12-01

    We consider ensembles of N × N symmetric matrices whose entries are weakly dependent random variables. We show that random dilution can change the limiting eigenvalue distribution of such matrices. We prove that under general and natural conditions the normalised eigenvalue counting function coincides with the semicircle (Wigner) distribution in the limit N → ∞. This can be explained by the observation that dilution (or more generally, random modulation) eliminates the weak dependence (or correlations) between random matrix entries. It also supports our earlier conjecture that the Wigner distribution is stable to random dilution and modulation.

  1. Dilute Oxygen Combustion Phase IV Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Riley, M.F.

    2003-04-30

    Novel furnace designs based on Dilute Oxygen Combustion (DOC) technology were developed under subcontract by Techint Technologies, Coraopolis, PA, to fully exploit the energy and environmental capabilities of DOC technology and to provide a competitive offering for new furnace construction opportunities. Capital cost, fuel, oxygen and utility costs, NOx emissions, oxide scaling performance, and maintenance requirements were compared for five DOC-based designs and three conventional air5-fired designs using a 10-year net present value calculation. A furnace direct completely with DOC burners offers low capital cost, low fuel rate, and minimal NOx emissions. However, these benefits do not offset the cost of oxygen and a full DOC-fired furnace is projected to cost $1.30 per ton more to operate than a conventional air-fired furnace. The incremental cost of the improved NOx performance is roughly $6/lb NOx, compared with an estimated $3/lb. NOx for equ8pping a conventional furnace with selective catalytic reduction (SCCR) technology. A furnace fired with DOC burners in the heating zone and ambient temperature (cold) air-fired burners in the soak zone offers low capital cost with less oxygen consumption. However, the improvement in fuel rate is not as great as the full DOC-fired design, and the DOC-cold soak design is also projected to cost $1.30 per ton more to operate than a conventional air-fired furnace. The NOx improvement with the DOC-cold soak design is also not as great as the full DOC fired design, and the incremental cost of the improved NOx performance is nearly $9/lb NOx. These results indicate that a DOC-based furnace design will not be generally competitive with conventional technology for new furnace construction under current market conditions. Fuel prices of $7/MMBtu or oxygen prices of $23/ton are needed to make the DOC furnace economics favorable. Niche applications may exist, particularly where access to capital is limited or floor space limitations

  2. Extended aroma extract dilution analysis profile of Shiikuwasha (Citrus depressa Hayata pulp essential oil

    Directory of Open Access Journals (Sweden)

    Yonathan Asikin

    2018-01-01

    Full Text Available Shiikuwasha pulp is an important raw material for producing citrus essential oils. The volatile aroma composition of pulp essential oil was evaluated using gas chromatography (GC methods, and its aroma profile was assessed using GC-olfactometry with an extended aroma extract dilution analysis (AEDA technique in regard to alterations of odor strength and sensorial perception throughout serial dilution steps. The essential oil comprised a mixture of 55 aroma compounds, including monoterpene hydrocarbon, sesquiterpene hydrocarbon, alcohol, aldehyde, ester, and oxide compounds. The predominant compounds were limonene [57.36% (4462.80 mg/100 g of pulp] and γ-terpinene [25.14% (1956.21 mg/100 g of pulp]. However, linalool was identified as one of the key aroma components providing the highest flavor dilution factor in AEDA, whilst three sesquiterpene hydrocarbons (δ-elemene, germacrene B, and bicyclosesquiphellandrene and two esters (heptyl acetate and decyl acetate had superior relative flavor activities. The extended AEDA profile identified variations in assessed odor perceptions, intensity, and duration of aroma components over dilution, whereas the 12 most odor-active compounds showed comparable odor strengths.

  3. Contrast-enhanced angiographic cone-beam computed tomography without pre-diluted contrast medium

    Energy Technology Data Exchange (ETDEWEB)

    Jo, K.I.; Kim, S.R.; Choi, J.H.; Kim, K.H.; Jeon, P. [Sungkyunkwan University School of Medicine, Department of Radiology, Samsung Medical Center, Gangnam-gu, Seoul (Korea, Republic of)

    2015-11-15

    Contrast-enhanced cone-beam computed tomography (CBCT) has been introduced and accepted as a useful technique to evaluate delicate vascular anatomy and neurovascular stents. Current protocol for CBCT requires quantitative dilution of contrast medium to obtain adequate quality images. Here, we introduce simple methods to obtain contrast-enhanced CBCT without quantitative contrast dilution. A simple experiment was performed to estimate the change in flow rate in the internal carotid artery during the procedure. Transcranial doppler (TCD) was used to evaluate the velocity change before and after catheterization and fluid infusion. In addition, 0.3 cm{sup 3}/s (n = 3) and 0.2 cm{sup 3}/s (n = 7) contrast infusions were injected and followed by saline flushes using a 300 mmHg pressure bag to evaluate neurovascular stent and host arteries. Flow velocities changed -15 ± 6.8 % and +17 ± 5.5 % from baseline during catheterization and guiding catheter flushing with a 300 mmHg pressure bag, respectively. Evaluation of the stents and vascular structure was feasible using this technique in all patients. Quality assessment showed that the 0.2 cm{sup 3}/s contrast infusion protocol was better for evaluating the stent and host artery. Contrast-enhanced CBCT can be performed without quantitative contrast dilution. Adequate contrast dilution can be achieved with a small saline flush and normal blood flow. (orig.)

  4. Automated spike preparation system for Isotope Dilution Mass Spectrometry (IDMS)

    International Nuclear Information System (INIS)

    Maxwell, S.L. III; Clark, J.P.

    1990-01-01

    Isotope Dilution Mass Spectrometry (IDMS) is a method frequently employed to measure dissolved, irradiated nuclear materials. A known quantity of a unique isotope of the element to be measured (referred to as the ''spike'') is added to the solution containing the analyte. The resulting solution is chemically purified then analyzed by mass spectrometry. By measuring the magnitude of the response for each isotope and the response for the ''unique spike'' then relating this to the known quantity of the ''spike'', the quantity of the nuclear material can be determined. An automated spike preparation system was developed at the Savannah River Site (SRS) to dispense spikes for use in IDMS analytical methods. Prior to this development, technicians weighed each individual spike manually to achieve the accuracy required. This procedure was time-consuming and subjected the master stock solution to evaporation. The new system employs a high precision SMI Model 300 Unipump dispenser interfaced with an electronic balance and a portable Epson HX-20 notebook computer to automate spike preparation

  5. Ab-initio calculations for dilute magnetic semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Belhadji, Brahim

    2008-03-03

    This thesis focusses on ab-initio calculations for the electronic structure and the magnetic properties of dilute magnetic semiconductors (DMS). In particular we aim at the understanding of the complex exchange interactions in these systems. Our calculations are based on density functional theory, being ideally suited for a description of the material specific properties of the considered DMS. Moreover we use the KKR Green function method in connection with the coherent potential approximation (CPA), which allows to include the random substitutional disorder in a mean field-like approximation for the electronic structure. Finally we calculate the exchange coupling constants J{sub ij} between two impurities in a CPA medium by using the Lichtenstein formula and from this calculate the Curie temperature by a numerically exact Monte Carlo method. Based on this analysis we found and investigated four different exchange mechanisms being of importance in DMS systems: Double exchange, p-d exchange, antiferromagnetic superexchanges, and ferromagnetic superexchange. A second topic we have investigated in this thesis is the pressure dependence of the exchange interactions and the Curie temperatures in (Ga,Mn)As and (In,Mn)As, using the LDA and the LDA+U approximations. Exact calculations of T{sub C} by Monte Carlo simulations show a somehow different behavior. (orig.)

  6. Ion separation from dilute electrolyte solutions by nanofiltration

    International Nuclear Information System (INIS)

    Garcia, Corazon M.

    2000-03-01

    Nanofiltration (NF) is a pressure-driven process which is considered potential for the separation of ionic species selectively from solutions containing mixture of electrolyte solutes. The lower operating pressure requirement of NF than reverse osmosis (RO) makes the earlier potentially economical. In the separation of ions, many authors believed that there are membranes with characteristic fixed surface charge and that the mechanism of separation of ions is by the differences in valences of the ions. In this study, experiments involving dilute single-solute and multiple-solute electrolyte solutions were performed using three different NF membranes. Permeate fluxes and ion rejections of the different species of ions in samples of permeate solutions were measured at varied conditions. The mechanism of separation in NF was determined based on the analysis of the trends and behavior of ion rejection relative to the solution temperature, pressure, type of solute, feed concentration and feed solution pH. The results of the experiments show that there is no evidence of the presence of fixed surface charge on the NF membranes. Ion separation was made possible by the combination of sieve effect and ion-hydration effect. Ions having higher hydration numbers showed higher ion rejection than those having lower hydration numbers. A method to determine the effective membrane pore size of NF membranes using hydrodynamic model was proposed. The proposed method is based on the assumptions that the membrane is neutral and that the separation is based on sieving effect. (Author)

  7. A theory of stable-isotope dilution mass spectrometry

    International Nuclear Information System (INIS)

    Pickup, J.F.; McPherson, C.K.

    1977-01-01

    In order to perform quantitative analysis using stable isotope dilution with mass spectrometry, an equation is derived which describes the relationship between the relative proportions of natural and labelled material and measured isotope ratios

  8. An overview the boron dilution issue in PWRs

    International Nuclear Information System (INIS)

    Hyvaerinen, J.

    1994-01-01

    The presentation is an overview of boron (boric acid) dilution in pressurized water reactors (PWRs). Boric acid has been widely used in PWRs as a dissolved poison, as one of the main reactivity controlling means, for a long time, from nearly but not quite from the beginning of the design, construction and operation of PWRs in the present-day sense. The specific safety issue, namely the risk of uncontrolled reactivity insertion due to inadvertent boron dilution, is discussed first, followed by a brief look on the history of boron usage in PWRs. A discussion of boron dilution phenomenology is presented next in general terms. Some particular concerns that boron dilution phenomena arouse in the minds of a regulator will also be presented before concluding with a brief look on the future of dissolved poisons. (11 refs.)

  9. A Cold Cycle Dilution Refrigerator for Space Applications, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The cold cycle dilution refrigerator is a continuous refrigerator capable of cooling to temperatures below 100 mK that makes use of a novel thermal magnetic pump....

  10. Preparation and structural characterization of the thermoluminescent material CaSO{sub 4}: Dy; Preparacion y caracterizacion estructural del material termoluminiscente CaSO{sub 4}: Dy

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez R, A.; Azorin, J. [UAM-I, 09340 Mexico D.F. (Mexico); Gonzalez M, P.R. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico); Rivera, T. [CICATA-IPN, Legaria 694, 11500 Mexico D.F. (Mexico)

    2005-07-01

    The grade of crystallinity of a material is important so that the one is presented the thermoluminescence phenomenon; for what is necessary to study those structural characteristic of a TL material and to correlate them with its TL response when being irradiated with ionizing radiation. The calcium sulfate activated with Dysprosium (CaSO{sub 4}: Dy) it is a material that has demonstrated its efficiency in the dosimetry of the ionizing radiation for the thermoluminescence method. In this work the structural characterization of this prepared material for the recrystallization method by means of the evaporation of the solvent and their relationship with their TL response is presented. The results showed that the best material to be used in thermoluminescent dosimetry presents a crystalline structure in orthorhombic phase and a particle size in the interval of 80 {mu}m to 200 {mu}m. (Author)

  11. Influence Of Dilution Factor For Activity Measurement Of 60CO

    International Nuclear Information System (INIS)

    Hermawan-Candra; Nazaroh; Ermi-Juita

    2003-01-01

    Influence of dilution factor for activity measurement of 60 Co has been studied. The aim of this research is to determine influence between activity measurement result of 60 Co before and after diluted. Measurement were done by using ionization chamber detectors system and gamma spectrometry system with NaI(TI) detector. Discrepancy within three ionization chambers measurements were 0.2% - 2.1% and NaI(Tl) were 3.5% - 6%. (author)

  12. Attentional sets influence perceptual load effects, but not dilution effects.

    Science.gov (United States)

    Benoni, Hanna; Zivony, Alon; Tsal, Yehoshua

    2014-01-01

    Perceptual load theory [Lavie, N. (1995). Perceptual load as a necessary condition for selective attention. Journal of Experimental Psychology: Human Perception and Performance, 21, 451-468.; Lavie, N., & Tsal, Y. (1994) Perceptual load as a major determinant of the locus of selection in visual attention. Perception & Psychophysics, 56, 183-197.] proposes that interference from distractors can only be avoided in situations of high perceptual load. This theory has been supported by blocked design manipulations separating low load (when the target appears alone) and high load (when the target is embedded among neutral letters). Tsal and Benoni [(2010a). Diluting the burden of load: Perceptual load effects are simply dilution effects. Journal of Experimental Psychology: Human Perception and Performance, 36, 1645-1656.; Benoni, H., & Tsal, Y. (2010). Where have we gone wrong? Perceptual load does not affect selective attention. Vision Research, 50, 1292-1298.] have recently shown that these manipulations confound perceptual load with "dilution" (the mere presence of additional heterogeneous items in high-load situations). Theeuwes, Kramer, and Belopolsky [(2004). Attentional set interacts with perceptual load in visual search. Psychonomic Bulletin & Review, 11, 697-702.] independently questioned load theory by suggesting that attentional sets might also affect distractor interference. When high load and low load were intermixed, and participants could not prepare for the presentation that followed, both the low-load and high-load trials showed distractor interference. This result may also challenge the dilution account, which proposes a stimulus-driven mechanism. In the current study, we presented subjects with both fixed and mixed blocks, including a mix of dilution trials with low-load trials and with high-load trials. We thus separated the effect of dilution from load and tested the influence of attentional sets on each component. The results revealed that whereas

  13. Effects of dissolved species on radiolysis of diluted seawater

    International Nuclear Information System (INIS)

    Hata, Kuniki; Hanawa, Satoshi; Kasahara, Shigeki; Motooka, Takafumi; Tsukada, Takashi; Muroya, Yusa; Yamashita, Shinichi; Katsumura, Yosuke

    2014-01-01

    Fukushima Daiichi Nuclear Power Plants (NPPs) experienced seawater injection into the cores and fuel pools as an emergent measure after the accident. After the accident, retained water has been continuously desalinized, and subsequently the concentration of chloride ion (Cl"-) has been kept at a lower level these days. These ions in seawater are known to affect water radiolysis, which causes the production of radiolytic products, such as hydrogen peroxide (H_2O_2), molecular hydrogen (H_2) and molecular oxygen (O_2). However, the effects of dissolved ions relating seawater on the production of the stable radiolytic products are not well understood in the diluted seawater. To understand of the production behavior in diluted seawater under radiation, radiolysis calculations were carried out. Production of H_2 is effectively suppressed by diluting by up to vol10%. The concentrations of oxidants (H_2O_2 and O_2) are also suppressed by dilution of dissolved species. The effect of oxidants on corrosion of materials is thought to be low when the seawater was diluted by less than 1 vol% by water. It is also shown that deaeration is one of the effective measure to suppress the concentrations of oxidants at a lower level for any dilution conditions. (author)

  14. Comparing the disk-diffusion and agar dilution tests for Neisseria gonorrhoeae antimicrobial susceptibility testing

    Directory of Open Access Journals (Sweden)

    Hsi Liu

    2016-11-01

    Full Text Available Abstract Background We assessed the validity of testing for antimicrobial susceptibility of clinical and mutant Neisseria gonorrhoeae (GC isolates by disk diffusion in comparison to agar dilution, and Etest® (bioMerieux, France, respectively, for three third generation extended spectrum cephalosporins (ESC: ceftriaxone (CRO, cefixime (CFX, and cefpodoxime (CPD. Methods One hundred and five clinical isolates and ten laboratory-mutants were tested following Clinical Laboratory Standard Institute (CLSI and manufacturer’s standards for each of the three methods. The measured diameters by the disk diffusion method were tested for correlation with the MIC values by agar dilution. In addition, comparisons with the Etest® were made. Categorical results for concordance, based on standard CLSI cutoffs, between the disk diffusion and the other two methods, respectively, were tested using the Chi-square statistics. Reproducibility was tested for CFX across a 6-month interval by repeated disk tests. Results Across all 115 specimens, the disk diffusion tests produced good categorical agreements, exhibiting concordance of 93.1%, 92.1%, and 90.4% with agar dilution and 93.0%, 92.1%, and 90.4% with Etest®, for CRO, CFX, and CPD, respectively. Pearson correlations between disk-diffusion diameters and agar dilution MIC’s were -0.59, -0.67, and -0.81 for CRO, CFX, and CPD, respectively. The correlations between disk diffusion and Etest® were -0.58, -0.73, and -0.49. Pearson correlation between the CFX disk readings over a 6-month interval was 91%. Conclusions Disk diffusion tests remain to be a useful, reliable and fast screening method for qualitative antimicrobial susceptibility testing for ceftriaxone, cefixime, and cefpodoxime.

  15. Preparation and calibration by liquid scintillation of a sample of Cl 36. Preparacion y calibracion por centelleo liquido de una muestra de Cl 36

    Energy Technology Data Exchange (ETDEWEB)

    Grau Malonda, A; Los Arcos, J M; Rodriguez Barquero, L; Suarez, C [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, Madrid (Spain)

    1989-01-01

    A procedure to prepare a sample of Clorine 36, as Li{sup 36}Cl, able to be measured by liquid scintillation counting, is described. The sample is chemically stable, with no variation of the quenching parameter up to 4 mg of LiCl per 15 ml of scintillator, keeps constant the counting efficiency for concentration higher than 40 {mu}g of Li{sup 36}Cl in that volume, and shows no deterioration over a 3 weed period. The Li{sup 36}Cl solution has been standarized using the free parameter method with different volumes of toluene, PCS and Instagel, to an uncertainty of 0,3% (Author).

  16. A model for the viscosity of dilute smectite gels

    International Nuclear Information System (INIS)

    Liu, Di; Liu, Longcheng

    2010-01-01

    the region of low volume fraction will also increase. This linear part is, in practice, a direct reflection of pair interaction, whereas the deviation from the linear part of inherent viscosity, appears at a volume fraction of ∼ 0.3%, indicates the onset of multiparticle interaction. Using the nonlinear least squares method to fit the experimental results, the model gives an expression for the relative viscosity of the sodium montmorillonite suspension as a function of the product of the effective intrinsic viscosity and the effective volume fraction, i.e. and it is actually the first term of the relative viscosity increment. The data points, originally scattered, now fall onto a single curve for all cases of NaCl concentrations; in practice about 99.8% of the experimental results are well represented by this expression which has well accounted not only for the pair interaction but also for the multiparticle interaction. Using the co-volume fraction instead of defining the effective volume fraction would violate the fact that the effect of pair interaction between suspended particle is more significant than that of the multiparticle interaction, even in dense suspension. This partly supports that our definition of the effective volume fraction is appropriate. The validation of the model against other experimental measurements has also been made. The results demonstrate that the model works quite well in predicting the viscosity of dilute suspensions of sodium montmorillonite in low ionic strength waters. The model will be used to quantify the release of colloidal particles from an expanding buffer around the canister containing spent nuclear fuel, together with a dynamic force balance model

  17. Ore loses and dilution of the ore vein no. 4 in the Zletovo mine, Republic of Macedonia

    Directory of Open Access Journals (Sweden)

    Bogatinovski Nikola L.

    2017-01-01

    Full Text Available Zletovo mines have a tradition of exploration and exploitation of vein lead-zinc ores for almost a century. Ore losses and dilutions have always been imperative in production since traditional old methods of mining and low-productivity mineralization are used. In conditions of classical and sub-level method excavations used, the calculated ore losses in ore vein No. 4 are 13.5%, while at the level of all excavations in the Zletovo mines dilution averages at 10%. Ore dilution is also an important technical parameter and several possible variants were calculated. When analyzing the dilution that occurs during the preparation of the sub-level corridor with parameters such: different drop angle (45-60o, constant thickness of 1.47 m as the average vein thickness in the calculated ore reserves, width of the sub-level corridor of 1.57 m or to the width of the ore vein No. 4 were added 10 cm (left and right to 5 cm as much as is taken in the calculation of the planned dilution and height of 2.5 m as suggested for this mining method, it can be noticed that the planned dilution during this method of mining ranges from 26.3% to 42.3%. In conditions of use of this underground method of excavation, parameters are selected that allow for the indicated lowering of the dilution. Namely, the thickness of the ore wire would be 1.47 m, the mining width would be 1.57 m, only 10 cm (left and right up to 5cm to the thickness of the ore vein will be added, the height difference between the consecutive levels would be 7.5 m, dip angle of 45 to 60°, and with the excavation the whole ore vein would be covered in height. On the basis of these parameters, models were prepared in which the ore vein would have a different dip angle, from which the values for the planned ore dilution ranged from 6.7 to 7.8%, which is significantly lower than the average dilution in the Zletovo Mine.

  18. Dermal absorption of a dilute aqueous solution of malathion

    Directory of Open Access Journals (Sweden)

    Scharf John

    2008-01-01

    Full Text Available Malathion is an organophosphate pesticide commonly used on field crops, fruit trees, livestock, agriculture, and for mosquito and medfly control. Aerial applications can result in solubilized malathion in swimming pools and other recreational waters that may come into contact with human skin. To evaluate the human skin absorption of malathion for the assessment of risk associated with human exposures to aqueous solutions, human volunteers were selected and exposed to aqueous solutions of malathion. Participants submerged their arms and hands in twenty liters of dilute malathion solution in either a stagnant or stirred state. The "disappearance method" was applied by measuring malathion concentrations in the water before and after human exposure for various periods of time. No measurable skin absorption was detected in 42% of the participants; the remaining 58% of participants measured minimal absorbed doses of malathion. Analyzing these results through the Hazard Index model for recreational swimmer and bather exposure levels typically measured in contaminated swimming pools and surface waters after bait application indicated that these exposures are an order of magnitude less than a minimal dose known to result in a measurable change in acetylcholinesterase activity. It is concluded that exposure to aqueous malathion in recreational waters following aerial bait applications is not appreciably absorbed, does not result in an effective dose, and therefore is not a public health hazard.

  19. Disposal of Low-Activity Liquid Effluents by Dilution

    Energy Technology Data Exchange (ETDEWEB)

    Bovard, P.; Candillon, C. [Atomic Energy Commission, Saclay (France)

    1960-07-01

    Nuclear centres are frequently faced with problems of disposal of sizeable quantities of low-activity liquid effluents. Under present conditions the most practicable solution seems to be to discharge them into a natural or artificial water system, so as to dilute them as much as possible and thus reduce their radioactive isotope content below the public health levels. This technique is employed by all nuclear centres in France, which use the following convenient outlets: Saclay: the artificial ponds made by Louis XIV to feed the great Versailles fountains; Fontenay-aux-Roses: the Paris sewer system; Grenoble: the river Isere; Marcoule: the river Rhone. Until 1957 the amount of waste was negligible. It is still very slight at the first three centres, only a few dozen millicuries a month. At Marcoule the activity of the effluents is somewhat greater, but the Rhone's rate of flow ensures a very low final content of radioactive elements. The increasing discharge of wastes into river systems calls for a close watch on changes in radioactivity in the environment (i.e. in air, water and soil), and especially on areas in which radioactive isotopes may accumulate. We have therefore made laboratory studies of the mechanics of radioactivity concentration, in order to improve our sampling methods and ascertain the movement of wastes.

  20. Tunable spin waves in diluted magnetic semiconductor nanoribbon

    Science.gov (United States)

    Lyu, Pin; Zhang, Jun-Yi

    2018-01-01

    The spin wave excitation spectrum in diluted magnetic semiconductor (DMS) nanoribbons was calculated by taking account of the quantum confinement effect of carriers and spin waves. By introducing the boundary condition for the spin waves, we derived the spin wave dispersion using the path-integral formulation and Green's function method. It was shown that the spin wave excitation spectrum is discrete due to the confinement effect and strongly dependent on the carrier density, the magnetic ion density, and the width of the nanoribbon. When the width of the nanoribbon is beyond the typical nanoscales, the size effect on the excitation energies of the spin waves disappears in our calculation, which is in qualitative agreement with no obvious size effect observed in the as-made nanodevices of (Ga,Mn)As in this size regime. Our results provide a potential way to control the spin waves in the DMS nanoribbon not only by the carrier density and the magnetic ion density but also by the nanostructure geometry.

  1. Flagging and correcting non-spectral matrix interferences with spatial emission profiles and gradient dilution in inductively coupled plasma-atomic emission spectrometry

    International Nuclear Information System (INIS)

    Cheung, Yan; Schwartz, Andrew J.; Chan, George C.-Y.; Hieftje, Gary M.

    2015-01-01

    Matrix interference remains one of the most daunting challenges commonly encountered in inductively coupled plasma-atomic emission spectrometry (ICP-AES). In the present study, a method is described that enables identification and correction of matrix interferences in axial-viewed ICP-AES through a combination of spatial mapping and on-line gradient dilution. Cross-sectional emission maps of the plasma are used to indicate the presence of non-spectral (plasma-related and sample-introduction-related) matrix interferences. In particular, apparent concentrations of an analyte species determined at various radial locations in the plasma differ in the presence of a matrix interference, which allows the interference to be flagged. To correct for the interference, progressive, on-line dilution of the sample, performed by a gradient high-performance liquid-chromatograph pump, is utilized. The spatially dependent intensities of analyte emission are monitored at different levels of sample dilution. As the dilution proceeds, the matrix-induced signal variation is reduced. At a dilution where the determined concentrations become independent of location in the plasma, the matrix interference is minimized. - Highlights: • Non-spectral matrix interference in ICP-AES is flagged and minimized. • Emission from different locations of the plasma are collected simultaneously. • Spatially dependent determined concentrations indicate the presence of interference. • Gradient dilution is performed on both calibration standards and sample. • Optimal dilution factor to minimize interference is found as dilution increases

  2. Flagging and correcting non-spectral matrix interferences with spatial emission profiles and gradient dilution in inductively coupled plasma-atomic emission spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Cheung, Yan; Schwartz, Andrew J.; Chan, George C.-Y.; Hieftje, Gary M., E-mail: hieftje@indiana.edu

    2015-08-01

    Matrix interference remains one of the most daunting challenges commonly encountered in inductively coupled plasma-atomic emission spectrometry (ICP-AES). In the present study, a method is described that enables identification and correction of matrix interferences in axial-viewed ICP-AES through a combination of spatial mapping and on-line gradient dilution. Cross-sectional emission maps of the plasma are used to indicate the presence of non-spectral (plasma-related and sample-introduction-related) matrix interferences. In particular, apparent concentrations of an analyte species determined at various radial locations in the plasma differ in the presence of a matrix interference, which allows the interference to be flagged. To correct for the interference, progressive, on-line dilution of the sample, performed by a gradient high-performance liquid-chromatograph pump, is utilized. The spatially dependent intensities of analyte emission are monitored at different levels of sample dilution. As the dilution proceeds, the matrix-induced signal variation is reduced. At a dilution where the determined concentrations become independent of location in the plasma, the matrix interference is minimized. - Highlights: • Non-spectral matrix interference in ICP-AES is flagged and minimized. • Emission from different locations of the plasma are collected simultaneously. • Spatially dependent determined concentrations indicate the presence of interference. • Gradient dilution is performed on both calibration standards and sample. • Optimal dilution factor to minimize interference is found as dilution increases.

  3. Quantification of Labile Soil Mercury by Stable Isotope Dilution Techniques

    Science.gov (United States)

    Shetaya, Waleed; Huang, Jen-How; Osterwalder, Stefan; Alewell, Christine

    2016-04-01

    Mercury (Hg) is a toxic element that can cause severe health problems to humans. Mercury is emitted to the atmosphere from both natural and anthropogenic sources and can be transported over long distances before it is deposited to aquatic and terrestrial environments. Aside from accumulation in soil solid phases, Hg deposited in soils may migrate to surface- and ground-water or enter the food chain, depending on its lability. There are many operationally-defined extraction methods proposed to quantify soil labile metals. However, these methods are by definition prone to inaccuracies such as non-selectivity, underestimation or overestimation of the labile metal pool. The isotopic dilution technique (ID) is currently the most promising method for discrimination between labile and non-labile metal fractions in soil with a minimum disturbance to soil-solid phases. ID assesses the reactive metal pool in soil by defining the fraction of metal both in solid and solution phases that is isotopically-exchangeable known as the 'E-value'. The 'E-value' represents the metal fraction in a dynamic equilibrium with the solution phase and is potentially accessible to plants. This is carried out by addition of an enriched metal isotope to soil suspensions and quantifying the fraction of metal that is able to freely exchange with the added isotope by measuring the equilibrium isotopic ratio by ICP-MS. E-value (mg kg-1) is then calculated as follows: E-Value = (Msoil/ W) (CspikeVspike/ Mspike) (Iso1IAspike -Iso2IAspikeRss / Iso2IAsoil Rss - Iso1IAsoil) where M is the average atomic mass of the metal in the soil or the spike, W is the mass of soil (kg), Cspike is the concentration of the metal in the spike (mg L-1), Vspike is the volume of spike (L), IA is isotopic abundance, and Rss is the equilibrium ratio of isotopic abundances (Iso1:Iso2). Isotopic dilution has been successfully applied to determine E-values for several elements. However, to our knowledge, this method has not yet

  4. On the equivalence of dilute antiferromagnets and ferromagnets in random external fields: Curie-Weiss models

    International Nuclear Information System (INIS)

    Perez, J.F.; Pontin, L.F.; Segundo, J.A.B.

    1985-01-01

    Using a method proposed by van Hemmen the free energy of the Curie-Weiss version of the site-dilute antiferromagnetic Ising model is computed, in the presence of an uniform magnetic field. The solution displays an exact correspondence between this model and the Curie-Weiss version of the Ising model in the presence of a random magnetic field. The phase diagrams are discussed and a tricritical point is shown to exist. (Author) [pt

  5. Spectrophotometric-isotope dilution determination of arsenic in soils and rock

    Science.gov (United States)

    Brown, F.W.; Simon, F.O.; Greenland, L.P.

    1975-01-01

    Arsenic in soil and rock samples may be determined in part-per-million concentrations using a radiochemical-isotope dilution method. Arsenic in the sample plus added As76 tracer is separated as arsine and determined spectrophotometrically as a molybdenum blue complex. The As76 activity in the absorbing solution allows corrections for chemical losses. A lower limit of 1 ppm is determinate in a 0.5-g sample.

  6. In-gel multiple displacement amplification of long DNA fragments diluted to the single molecule level.

    Science.gov (United States)

    Michikawa, Yuichi; Sugahara, Keisuke; Suga, Tomo; Ohtsuka, Yoshimi; Ishikawa, Kenichi; Ishikawa, Atsuko; Shiomi, Naoko; Shiomi, Tadahiro; Iwakawa, Mayumi; Imai, Takashi

    2008-12-15

    The isolation and multiple genotyping of long individual DNA fragments are needed to obtain haplotype information for diploid organisms. Limiting dilution of sample DNA followed by multiple displacement amplification is a useful technique but is restricted to short (reaction (PCR)-ready form. The haplotypes of seven SNPs spanning 240 kb of the DNA surrounding the human ATM gene region on chromosome 11 were determined for 10 individuals, demonstrating the feasibility of this new method.

  7. Theory of the high-frequency limiting viscosity of a dilute polymer solution. Pt. 2

    Energy Technology Data Exchange (ETDEWEB)

    Doi, M; Nakajima, H; Wada, Y

    1976-06-01

    High-frequency limiting viscosities of dilute polymer solutions are calculated on the basis of the author's previous theory for (1) necklace model of a chain with constant bond length and bond angle under a hindering rotational potential, and (2) broken rod model consisting of N rods with equal length connected by universal joints. Exact treatment is possible for a once-broken rod model, but the Monte Carlo method is used in the other calculations.

  8. Measurement parameter selection for quantitative isotope dilution gas chromatography/mass spectrometry

    International Nuclear Information System (INIS)

    Colby, B.N.; Rosecrance, A.E.; Colby, M.E.

    1981-01-01

    By use of the two-isotope model of isotope dilution, selection criteria were developed for identifying optimum m/z's for quantitation of compounds by gas chromatography/mass spectrometry. In addition, it was possible to predict the optimum ratio of naturally abundant to labeled compound and to identify appropriate data reduction methods. The validity of these predictions was confirmed by using experimental GC/MS data for several organic compounds

  9. Approaches of aroma extraction dilution analysis (AEDA) for headspace solid phase microextraction and gas chromatography-olfactometry (HS-SPME-GC-O): Altering sample amount, diluting the sample or adjusting split ratio?

    Science.gov (United States)

    Feng, Yunzi; Cai, Yu; Sun-Waterhouse, Dongxiao; Cui, Chun; Su, Guowan; Lin, Lianzhu; Zhao, Mouming

    2015-11-15

    Aroma extract dilution analysis (AEDA) is widely used for the screening of aroma-active compounds in gas chromatography-olfactometry (GC-O). In this study, three aroma dilution methods, (I) using different test sample volumes, (II) diluting samples, and (III) adjusting the GC injector split ratio, were compared for the analysis of volatiles by using HS-SPME-AEDA. Results showed that adjusting the GC injector split ratio (III) was the most desirable approach, based on the linearity relationships between Ln (normalised peak area) and Ln (normalised flavour dilution factors). Thereafter this dilution method was applied in the analysis of aroma-active compounds in Japanese soy sauce and 36 key odorants were found in this study. The most intense aroma-active components in Japanese soy sauce were: ethyl 2-methylpropanoate, ethyl 2-methylbutanoate, ethyl 3-methylbutanoate, ethyl 4-methylpentanoate, 3-(methylthio)propanal, 1-octen-3-ol, 2-methoxyphenol, 4-ethyl-2-methoxyphenol, 2-methoxy-4-vinylphenol, 2-phenylethanol, and 4-hydroxy-5-ethyl-2-methyl-3(2H)-furanone. Copyright © 2015. Published by Elsevier Ltd.

  10. Preparation and characterization of alpha sources as standards in the actinides separation; Preparacion y caracterizacion de fuentes alfa como estandares en la separacion de actinidos

    Energy Technology Data Exchange (ETDEWEB)

    Monroy G, F.; Escobar A, L.; Zepeda R, C. P.; Balcazar, M., E-mail: fabiola.monroy@inin.gob.mx [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2017-09-15

    The radioisotopes Am-243, Cm-244, Pu-242 and U-232 are used as radioactive tracers in the processes of separation and quantification of the radioisotopes of Am, Cm, Pu and U contained in radioactive and nuclear wastes, with the purpose of determining the efficiency of said processes. For this, in this work, alpha sources of Am-243, Cm-244, Pu-242 and U-232 standards were prepared by two methods: evaporation and electro-deposition, and they were analyzed by means of alpha spectrometry to verify the properties of these radioactive standards. The alpha sources prepared by electro-deposition were analyzed by Raman spectrometry to determine the chemical form in which the actinide was deposited; the good homogeneity in the distribution of the deposit was determined with solid nuclear trace detectors. The resolution of the alpha spectra obtained with surface barrier detectors of the standards is greater when deposited by electro-deposition. The FWHM of the alpha sources prepared by electro-deposition is always lower than that prepared by evaporation. Actinides are electrodeposited in the form of hydroxides and oxo compounds. (Author)

  11. Modeling syngas-fired gas turbine engines with two dilutants

    Science.gov (United States)

    Hawk, Mitchell E.

    2011-12-01

    Prior gas turbine engine modeling work at the University of Wyoming studied cycle performance and turbine design with air and CO2-diluted GTE cycles fired with methane and syngas fuels. Two of the cycles examined were unconventional and innovative. The work presented herein reexamines prior results and expands the modeling by including the impacts of turbine cooling and CO2 sequestration on GTE cycle performance. The simple, conventional regeneration and two alternative regeneration cycle configurations were examined. In contrast to air dilution, CO2 -diluted cycle efficiencies increased by approximately 1.0 percentage point for the three regeneration configurations examined, while the efficiency of the CO2-diluted simple cycle decreased by approximately 5.0 percentage points. For CO2-diluted cycles with a closed-exhaust recycling path, an optimum CO2-recycle pressure was determined for each configuration that was significantly lower than atmospheric pressure. Un-cooled alternative regeneration configurations with CO2 recycling achieved efficiencies near 50%, which was approximately 3.0 percentage points higher than the conventional regeneration cycle and simple cycle configurations that utilized CO2 recycling. Accounting for cooling of the first two turbine stages resulted in a 2--3 percentage point reduction in un-cooled efficiency, with air dilution corresponding to the upper extreme. Additionally, when the work required to sequester CO2 was accounted for, cooled cycle efficiency decreased by 4--6 percentage points, and was more negatively impacted when syngas fuels were used. Finally, turbine design models showed that turbine blades are shorter with CO2 dilution, resulting in fewer design restrictions.

  12. Dilution Ratios for HB Line Phase I Eductor System

    International Nuclear Information System (INIS)

    Steimke, J.L.

    2002-01-01

    HB Line Phase I product transfer includes an eductor which transfers liquid from Product Hold Tank (PHT) RT-33 or RT-34 to Tank 11.1. The eductor also dilutes the liquid from the PHT with eductant. Dilution must be reliably controlled because of criticality concerns with H Canyon Tanks. The eductor system, which contains a 1 inch Model 264 Schutte and Koerting eductor, was previously modeled [1] in 1998 and dilution ratios were calculated for different flow restrictors, eductant pressures and densities for the eductant and the contents of the PHT. The previous calculation was performed using spreadsheet software no longer supported at SRS. For the previous work dilution ratio was defined as the volume of eductant consumed divided by volume of PHT contents transferred. Since 1998 HB Line Engineering has changed the definition of dilution ratio to the total volume of liquid, eductant consumed plus the volume of PHT liquid transferred, divided by the volume of PHT liquid transferred. The 1998 base case calculation was for a restrictor diameter of 0.334 inches, an eductant supply pressure of 15 psig, full PHT, an eductant specific gravity of 1.385 and a PHT density of 1.015. The base case dilution ratio calculated in 1998 using the current definition was 3.52. After accounting for uncertainty the minimum dilution ratio decreased to 3.23. In 2001 HB Line Engineering requested that the calculation be repeated for a manganous nitrate solution eductant and also a process water eductant. The other conditions were the same as for the 1998 calculation. The objective of this report is to document the calculations and the results

  13. Determination of gold of No. 501 uranium deposits and soil samples by cold leaching gold in dilute aqua regia and collection on activated charcoal

    International Nuclear Information System (INIS)

    Shen Maogen; Yao Liying.

    1989-01-01

    The gold determination method is described by cold leaching gold in dilute aqua regia and collection on activated charcoal and presents the results obtained in determining gold of uranium deposits and soil samples

  14. ISOTOPE-DILUTION AMMONIA CHEMICAL-IONIZATION MASS FRAGMENTOGRAPHIC ANALYSIS OF URINARY 3-O-METHYLATED CATECHOLAMINE METABOLITES - RAPID SAMPLE CLEANUP BY DERIVATIZATION AND EXTRACTION OF LYOPHILIZED SAMPLES

    NARCIS (Netherlands)

    KEMA, IP; MEIBORG, G; NAGEL, GT; STOB, GJ; MUSKIET, FAJ

    1993-01-01

    We developed a method for simultaneous quantification of the urinary 3-O-methylated catecholamine metabolites 3-methoxytyramine, normetanephrine and metanephrine by stable isotope-dilution ammonia chemical ionization mass fragmentography. Prepurification of lyophilized samples was done by

  15. Preparation of the radiopharmaceutical {sup 99m} Tc-HYNIC-[Lys{sup 3}]-BN; Preparacion del radiofarmaco {sup 99m} Tc-HYNIC-[Lys{sup 3}]-BN

    Energy Technology Data Exchange (ETDEWEB)

    Conde S, E [Universidad Autonoma del Estado de Mexico, Facultad de Quimica, 50000 Toluca, Estado de Mexico (Mexico)

    2007-07-01

    In accordance with their design, the radiopharmaceuticals can be divided in three generations. The radiopharmaceuticals of third generation are used in nuclear medicine to obtain images of specific molecular targets, and they are only in their capacity to detect in vivo such specific biochemical places as receivers and enzymes. The receivers of regulator peptides are over expressed in numerous carcinogenic cells. Those receivers have been used as molecular targets of radiolabelled peptides to locate cancerous tumors. The small peptide bombesin (BN, 14 amino acids) it was isolated of the frog skin and it belongs to a wide neuropeptides group with many biological functions. The equivalent human is the liberator peptide of the gastrin (GRP, 27 amino acids) and his receivers (r-GRP) that are on expressed in the membranes of the tumor cells. The receiving subtype 2 of bombesin (receiving GRP) it is on expressed in several human tumors including breast, prostate, lung cells and pancreatic cancer. Some radiopharmaceuticals similar of BN has been developed that were prepared to be used in nuclear medicine for the detection of wicked tumors and to evidence prostate cancers, breast and of lymphatic nodules. A technique was developed to allow the conjugation of HYNIC-[Lys3]-BN that allowed to obtain this product with a high purity. The identity was determined by HPLC chromatography. It was necessary the validation of the method and the HPLC system, to assure that the results were reliable. Linearity, specificity, accuracy and precision parameters were analyzed, that are those required by the Mexican pharmacopoeia for chromatographic methods. With this conjugated a formulation for lyophilized kits were analyzed, with the purpose of obtaining a radiochemical purity, after the labelled one with {sup 99m}Tc, bigger to 95%; the components used in the nucleus-equipment should favor the conjugation of the {sup 99m}Tc by means of a ligands exchange between the tricine and the

  16. Can tritiated water-dilution space accurately predict total body water in chukar partridges

    International Nuclear Information System (INIS)

    Crum, B.G.; Williams, J.B.; Nagy, K.A.

    1985-01-01

    Total body water (TBW) volumes determined from the dilution space of injected tritiated water have consistently overestimated actual water volumes (determined by desiccation to constant mass) in reptiles and mammals, but results for birds are controversial. We investigated potential errors in both the dilution method and the desiccation method in an attempt to resolve this controversy. Tritiated water dilution yielded an accurate measurement of water mass in vitro. However, in vivo, this method yielded a 4.6% overestimate of the amount of water (3.1% of live body mass) in chukar partridges, apparently largely because of loss of tritium from body water to sites of dissociable hydrogens on body solids. An additional source of overestimation (approximately 2% of body mass) was loss of tritium to the solids in blood samples during distillation of blood to obtain pure water for tritium analysis. Measuring tritium activity in plasma samples avoided this problem but required measurement of, and correction for, the dry matter content in plasma. Desiccation to constant mass by lyophilization or oven-drying also overestimated the amount of water actually in the bodies of chukar partridges by 1.4% of body mass, because these values included water adsorbed onto the outside of feathers. When desiccating defeathered carcasses, oven-drying at 70 degrees C yielded TBW values identical to those obtained from lyophilization, but TBW was overestimated (0.5% of body mass) by drying at 100 degrees C due to loss of organic substances as well as water

  17. The Preparation and Thermodynamics of Europium Dicarbide; Preparation et Thermodynamique du Bicarbure d'Europium; Poluchenie i termodinamicheskie svojstva dikarbida evropiya; Preparacion y Termodinamica del Dicarburo de Europio

    Energy Technology Data Exchange (ETDEWEB)

    Gebelt, R. E. [Oklahoma State University, Stillwater, OK (United States); Eick, H. A. [Michigan State University, East Lansing, MI (United States)

    1966-01-15

    Europium dicarbide has been prepared by the reaction of europium metal and graphite in a stainless steel bomb. Chemical analysis indicates an average composition of the product of EuC{sub 1.87{+-}0.07}. X-ray powder diffraction analysis shows the compound to be of body-centred tetragonal symmetry, space group D{sup 17}{sub 4}n-14/mm , with lattice parameters: a{sub 0} = 4.045 A; c{sub 0} = 6.645 A. Vapour phase chromatographic analysis indicates that 98% of the gaseous product of acid hydrolysis of europium dicarbide is the hydrocarbon acetylene. These analytical data, together with the lattice parameters, indicate that europium dicarbide resembles alkaline earth dicarbides more than it resembles the other lanthanon dicarbides. The vaporization of europium dicarbide over the temperature range 1130 to 1600 Degree-Sign K was investigated by the Knudsen effusion method. The effusate was either collected and analysed chemically or observed with a time-of-flight mass spectrometer. Thedata presented here are based predominantly on the massspectro- metric observations since they yielded more reproducible data than the collection technique. Gaseous europium dicarbide and europium, in concentrations of 1 and 99%respectively, were found in the effusate. Instrument limitations prevented determination of the concentration of the gaseous dicarbide as a function of temperature. Calibration of the mass spectrometer with silver permitted the calculation of the pressures corresponding to the observed ion intensities. An empirical equation was fitted to the data for europium by the method of least squares. From the second law of thermodynamics the following values were calculated for the reaction: EuC{sub 2} Rightwards-Harpoon-Over-Leftwards-Harpoon Eu(g) + 2C (graphite); {Delta}H{sup 0}{sub 298} = 51.09{+-}1.42kcal/mole; {Delta}H{sup 0}{sub 298} = 18.43 {+-} 1.75 e.u. Values of the free energy function for EuC{sub 2}(s) were estimated and combined with published data to yield for

  18. Mobile Melt-Dilute Treatment for Russian Spent Nuclear Fuel

    International Nuclear Information System (INIS)

    Peacock, H.

    2002-01-01

    Treatment of spent Russian fuel using a Melt-Dilute (MD) process is proposed to consolidate fuel assemblies into a form that is proliferation resistant and provides critically safety under storage and disposal configurations. Russian fuel elements contain a variety of fuel meat and cladding materials. The Melt-Dilute treatment process was initially developed for aluminum-based fuels so additional development is needed for several cladding and fuel meat combinations in the Russian fuel inventory (e.g. zirconium-clad, uranium-zirconium alloy fuel). A Mobile Melt-Dilute facility (MMD) is being proposed for treatment of spent fuels at reactor site storage locations in Russia; thereby, avoiding the costs of building separate treatment facilities at each site and avoiding shipment of enriched fuel assemblies over the road. The MMD facility concept is based on laboratory tests conducted at the Savannah River Technology Center (SRTC), and modular pilot-scale facilities constructed at the Savannah River Site for treatment of US spent fuel. SRTC laboratory tests have shown the feasibility of operating a Melt-Dilute treatment process with either a closed system or a filtered off-gas system. The proposed Mobile Melt-Dilute process is presented in this paper

  19. Initial magnetic susceptibility of the diluted magnetopolymer elastic composites

    International Nuclear Information System (INIS)

    Borin, D.Yu.; Odenbach, S.

    2017-01-01

    In this work diluted magnetopolymer elastic composites based on magnetic microparticles are experimentally studied. Considered samples have varied concentration of the magnetic powder and different structural anisotropy. Experimental data on magnetic properties are accomplished by microstructural observations performed using X-Ray tomography. Influence of the particles amount and structuring effects on the initial magnetic susceptibility of the composites as well as the applicability of the Maxwell-Garnett approximation, which is widely used in considerations of magnetopolymer elastic composites, are evaluated. It is demonstrated that the approximation works well for diluted samples containing randomly distributed magnetic particles and for the diluted samples with chain-like structures oriented perpendicular to an externally applied field, while it fails to predict the susceptibility of the samples with structures oriented parallel to the field. Moreover, it is shown, that variation of the chains morphology does not significantly change the composite initial magnetic susceptibility. - Highlights: • The Maxwell-Garnet prediction works well for the diluted isotropic composites. • The Maxwell-Garnet prediction can be used for composites with structures oriented perpendicular to an applied field. • Chains oriented parallel to an applied field significantly increase the composite initial magnetic susceptibility. • The number and thickness of chains is not of the highest importance for the diluted composites. • The crucial reason of the observed effect is expected to be the demagnetisation factor of the chains.

  20. A probabilistic analysis of rapid boron dilution scenarios

    International Nuclear Information System (INIS)

    Kohut, P.; Diamond, D.J.

    1993-01-01

    A probabilistic and deterministic analysis of a rapid boron dilution scenario related to reactor restart was performed. The event is initiated by a loss of off-site power during the startup dilution process. The automatic restart of the charging pump in such cases may lead to the accumulation of a diluted slug of water in the lower plenum. The restart of the reactor coolant pumps may send the diluted slug through the core, adding sufficient reactivity to overcome the shutdown margin and cause a power excursion. The concern is that the power excursion is sufficient in certain circumstances to cause fuel damage. The estimated core damage frequency based on the scoping analysis is 1.0--3.0E-05/yr for the plants analyzed. These are relatively significant values when compared to desirable goals. The analysis contained assumptions related to plant specific design characteristics which may lead to non-conservative estimates. The most important conservative assumptions were that mixing of the injected diluted water is insignificant and that fuel damage occurs when the slug passes through the core

  1. Preparation and stability of the {sup 99m} Tc-HNE{sub 2} radiopharmaceutical; Preparacion y estabilidad del radiofarmaco {sup 99m} TC-HNE{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Estrada T, J

    2002-07-01

    A radiopharmaceutical is all substance containing a radioactive atom inside of its structure and what because of its pharmaceutical form, quantity and quality of radiation can be administered in the human beings with diagnostic or therapeutic aims. With the purpose to developing effective radiopharmaceuticals it is necessary to pick carefully the appropriate radionuclide in combination with the In vivo localization and the pharmacon kinetic properties of the carrier molecule. The peptides are designed by the nature to stimulate, regulate or inhibit numerous life functions, they act mainly as information transmitters and activity coordinators of several tissues in the body; it has been found that such substances are present in cells and in the body fluids in quantities extremely small, therefore the peptides have been considered as ideal agents for therapeutic applications. Elastase of human neutrophylls is a 29 kDa protease which is produced in high levels inside the neutrophyll and it is released as response for an inflammatory stimulus in infection/inflammation places. Once it liberated is quickly inhibited by the anti elastase {alpha} tripsine (HNE-2) peptide. Therefore, the neutrophylls elastase is considered as a target to obtain In vivo images of inflammatory/infectious processes by the intravenous application of {sup 99m} Tc-HNE-2. The objective of this work was to develop a labelling method with {sup 99m} Tc for the inhibitor peptide of the human neutrophyll elastase (HNE-2). Likewise, for evaluating its In vivo and In vitro stabilities. The methodology which was followed as first step to conjugate the (HNE-2) peptide with the bi chelating agents HYNIC and DTPA capable to chelate the {sup 99m} Tc metal. Therefore the attachment reactions to the peptide were realized starting from the NHS and HYNIC and the DTPA anhydride in buffer of 0.1 M, pH= 9.0/DMF (10:1) bicarbonates with a molar relation peptide/bi chelating agent 1:5. For the purification of the

  2. Non-diluted seawater enhances nasal ciliary beat frequency and wound repair speed compared to diluted seawater and normal saline.

    Science.gov (United States)

    Bonnomet, Arnaud; Luczka, Emilie; Coraux, Christelle; de Gabory, Ludovic

    2016-10-01

    The regulation of mucociliary clearance is a key part of the defense mechanisms developed by the airway epithelium. If a high aggregate quality of evidence shows the clinical effectiveness of nasal irrigation, there is a lack of studies showing the intrinsic role of the different irrigation solutions allowing such results. This study investigated the impact of solutions with different pH and ionic compositions, eg, normal saline, non-diluted seawater and diluted seawater, on nasal mucosa functional parameters. For this randomized, controlled, blinded, in vitro study, we used airway epithelial cells obtained from 13 nasal polyps explants to measure ciliary beat frequency (CBF) and epithelial wound repair speed (WRS) in response to 3 isotonic nasal irrigation solutions: (1) normal saline 0.9%; (2) non-diluted seawater (Physiomer®); and (3) 30% diluted seawater (Stérimar). The results were compared to control (cell culture medium). Non-diluted seawater enhanced the CBF and the WRS when compared to diluted seawater and to normal saline. When compared to the control, it significantly enhanced CBF and slightly, though nonsignificantly, improved the WRS. Interestingly, normal saline markedly reduced the number of epithelial cells and ciliated cells when compared to the control condition. Our results suggest that the physicochemical features of the nasal wash solution is important because it determines the optimal conditions to enhance CBF and epithelial WRS thus preserving the respiratory mucosa in pathological conditions. Non-diluted seawater obtains the best results on CBF and WRS vs normal saline showing a deleterious effect on epithelial cell function. © 2016 The Authors International Forum of Allergy & Rhinology, published by ARSAAOA, LLC.

  3. Determination of nanogram amounts of iodide by electrochemical isotope dilution analysis

    International Nuclear Information System (INIS)

    Gabrielsson, A.-B.; Beronius, P.

    1976-01-01

    A known quantity of iodide in ethanol as solvent was labelled with 131 I-and subsequently diluted with a predetermined amount of inactive iodide. Specific activities before and after the isotope dilution were established by anodically depositing small fractions of the halide in each sample on rotating silver micro electrodes and determining the activities of the electrodeposits. The lowest concentration of iodide used in any analysis was 1.10 -5 M. Further deposition studies revealed that iodide can be deposited with 1 100% current efficiency on the rotating silver micro electrode for concentration down to 2.4.10 -6 M. Electrodeposition studies for still lower concentrations have not yet been undertaken. These results suggest that amounts of iodide ion down to about 10 ng, and possibly still smaller quantitites, might be determined with the method developed. Amounts from 42 ng to 1 μg can be determined with an error of 2.5%. (T.G.)

  4. The interlaboratory experiment IDA-72 on mass spectrometric isotope dilution analysis. Vol. 1

    International Nuclear Information System (INIS)

    Beyrich, W.; Drosselmeyer, E.

    1975-07-01

    Within the framework of the Safeguards Project of the Federal Republic of Germany at the Nuclear Research Center Karlsruhe an analytical intercomparison program was carried out in cooperation with 22 laboratories of 13 countries or international organizations. The main objective was the acquisition of basic data on the errors involved in the mass spectrometric isotope dilution analysis if it is applied to the determination of uranium and plutonium in diluted active feed solutions of reprocessing plants in routine operation. The results were evaluated by statistical methods mainly in regard to the calculation of the estimates of the variances for the different error components contributing to the total error of this analytical technique. Furthermore, the performance of two new methods for sample conditioning suggested by the International Atomic Energy Agency, Vienna, and the European Institute for Transuranium Elements (EURATOM), Karlsruhe, was successfully tested. The results of some investigations on the stability of diluted high active feed solutions and on comparison analysis by X-ray fluorescence spectrometry are also included. Data on the analytical efforts (manhours) invested in this study are reported as well as general experiences made in the organization and performance of an experiment on such an extended international level. (orig.) [de

  5. Sensitivity of the activated partial thromboplastin time, the dilute Russell's viper venom time, and the kaolin clotting time for the detection of the lupus anticoagulant: a direct comparison using plasma dilutions.

    Science.gov (United States)

    Martin, B A; Branch, D W; Rodgers, G M

    1996-01-01

    Increasing dilutions of lupus anticoagulant (LA) plasmas from twelve patients were used to directly compare the sensitivity of four tests for LA. The tests evaluated were the modified Bell and Alton activated partial thromboplastin time (APTT), an APTT using a commercially prepared partial thromboplastin (Platelin LS APTT), a modified dilute Russell's viper venom time (DRVVT), and a modified kaolin clotting time (KCT). LAs were detected in all twelve plasmas by each of three tests and eleven of twelve plasmas in a fourth test when undiluted patient plasma was used. Repeating the tests after diluting the LA plasmas with normal platelet-free plasma (PFP) showed that the KCT was the most sensitive test for LA, detecting eleven of twelve LAs at a dilution of 10% patient plasma and ten of twelve LAs at a dilution of 5% patient plasma. The modified Bell and Alton APTT and the modified DRVVT had similar sensitivities at a patient plasma concentration of 10%, detecting seven of twelve and eight of twelve LAs, respectively. The Platelin LS APTT detected only four of twelve LAs at a patient plasma concentration of 10%. Our results indicate that the modified KCT is a sensitive method for the detection of LAs. The modified Bell and Alton APTT and the DRVVT were less sensitive.

  6. Measurement and correlation of infinite dilution activity coefficients of alcohols in hexadecane and tetradecane; Hexadecane oyobi tetradecane chu no alcohol rui no mugen kishaku katsuryo keisu no sokutei narabini sokan

    Energy Technology Data Exchange (ETDEWEB)

    Fukuchi, K.; Miyoshi, K. [Ube National College of Technology, Yamaguchi (Japan)

    1996-03-10

    The infinite dilution activity coefficients of alcohols (methanol, ethanol, 1-propanol, 2-propano, 1-butanol, and 2-butanol) in heavy paraffinic hydrocarbons (hexadecane and tetradecane) were measured in the region 20-80{degree}C by a gas stripping method. The ASOG model was applied to calculate the infinite dilution activity coefficients. The infinite dilution activity coefficients can be correlated by adjusting the group interaction parameters between hydroxy and methyl groups. 8 refs., 3 figs., 4 tabs.

  7. Thermal diffusion in dilute nanofluids investigated by photothermal interferometry

    International Nuclear Information System (INIS)

    Philip, J; Nisha, M R

    2010-01-01

    We have carried out a theoretical analysis of the dependence of the particle mass fraction on the thermal diffusivity of dilute suspensions of nanoparticles in liquids (dilute nanofluids). The analysis takes in to account adsorption of an ordered layer of solvent molecules around the nanoparticles. It is found that thermal diffusivity decreases with mass fraction for sufficiently small particle sizes. Beyond a critical particle size thermal diffusivity begins to increase with mass fraction for the same system. The results have been verified experimentally by measuring the thermal diffusivity of dilute suspensions of TiO 2 nanoparticles dispersed in polyvinyl alcohol (PVA) medium. The effect is attributed to Kapitza resistance of thermal waves in the medium.

  8. Isotope dilution ICP-MS with laser-assisted sample introduction for direct determination of sulfur in petroleum products

    Energy Technology Data Exchange (ETDEWEB)

    Boulyga, Sergei F.; Heilmann, Jens; Heumann, Klaus G. [Johannes Gutenberg-University Mainz (Germany). Institute of Inorganic Chemistry and Analytical Chemistry

    2005-08-01

    Inductively coupled plasma isotope dilution mass spectrometry (ICP-IDMS) with direct laser-assisted introduction of isotope-diluted samples into the plasma, using a laser ablation system with high ablation rates, was developed for accurate sulfur determinations in different petroleum products such as 'sulfur-free' premium gasoline, diesel fuel, and heating oil. Two certified gas oil reference materials were analyzed for method validation. Two different {sup 34}S-enriched spike compounds, namely, elementary sulfur dissolved in xylene and dibenzothiophene in hexane, were synthesized and tested for their usefulness in this isotope dilution technique. The isotope-diluted sample was adsorbed on a filter-paper-like material, which was fixed in a special holder for irradiation by the laser beam. Under these conditions no time-dependent spike/analyte fractionation was only observed for the dibenzothiophene spike during the laser ablation process, which means that the measured {sup 34}S/{sup 32}S isotope ratio of the isotope-diluted sample remained constant - a necessary precondition for accurate results with the isotope dilution technique. A comparison of LA-ICP-IDMS results with the certified values of the gas oil reference materials and with results obtained from ICP-IDMS analyses with wet sample digestion demonstrated the accuracy of the new LA-ICP-IDMS method in the concentration range of 9.2 {mu}g g{sup -1} ('sulfur-free' premium gasoline) to 10.4 mg g{sup -1} (gas oil reference material BCR 107). The detection limit for sulfur by LA-ICP-IDMS is 0.04 {mu}g g{sup -1} and the analysis time is only about 10 min, which therefore also qualifies this method for accurate determinations of low sulfur contents in petroleum products on a routine level. (orig.)

  9. Isotope dilution ICP-MS with laser-assisted sample introduction for direct determination of sulfur in petroleum products.

    Science.gov (United States)

    Boulyga, Sergei F; Heilmann, Jens; Heumann, Klaus G

    2005-08-01

    Inductively coupled plasma isotope dilution mass spectrometry (ICP-IDMS) with direct laser-assisted introduction of isotope-diluted samples into the plasma, using a laser ablation system with high ablation rates, was developed for accurate sulfur determinations in different petroleum products such as 'sulfur-free' premium gasoline, diesel fuel, and heating oil. Two certified gas oil reference materials were analyzed for method validation. Two different 34S-enriched spike compounds, namely, elementary sulfur dissolved in xylene and dibenzothiophene in hexane, were synthesized and tested for their usefulness in this isotope dilution technique. The isotope-diluted sample was adsorbed on a filter-paper-like material, which was fixed in a special holder for irradiation by the laser beam. Under these conditions no time-dependent spike/analyte fractionation was only observed for the dibenzothiophene spike during the laser ablation process, which means that the measured 34S/32S isotope ratio of the isotope-diluted sample remained constant-a necessary precondition for accurate results with the isotope dilution technique. A comparison of LA-ICP-IDMS results with the certified values of the gas oil reference materials and with results obtained from ICP-IDMS analyses with wet sample digestion demonstrated the accuracy of the new LA-ICP-IDMS method in the concentration range of 9.2 microg g(-1) ('sulfur-free' premium gasoline) to 10.4 mg g(-1) (gas oil reference material BCR 107). The detection limit for sulfur by LA-ICP-IDMS is 0.04 microg g(-1) and the analysis time is only about 10 min, which therefore also qualifies this method for accurate determinations of low sulfur contents in petroleum products on a routine level.

  10. Modeling of dilute and dense dispersed fluid-particle flow

    Energy Technology Data Exchange (ETDEWEB)

    Laux, Harald

    1998-08-01

    A general two-fluid model is derived and applied in CFD computations to various test cases of important industrial multiphase flows. It is general in the sense of its applicability to dilute and dense dispersed fluid-particle flows. The model is limited to isothermal flow without mass transfer and only one particle phase is described. The instantaneous fluid phase equations, including the phase interaction terms, are derived from a volume averaging technique, and the instantaneous particle phase equations are derived from the kinetic theory of granular material. Whereas the averaging procedure, the treatment of the interaction terms, and the kinetic theory approach have been reported in literature prior to this work the combination of the approaches is new. The resulting equations are derived without ambiguity in the interpretation of the particle phase pressure (equation-of-state of particle phase). The basic modeling for the particle phase is improved in two steps. Because in the basic modeling only stresses due to kinetic and collisional interactions are included, a simple model for an effective viscosity is developed in order to allow also frictional stresses within the particle phase. Moreover, turbulent stresses and turbulent dispersion of particles play often an important role for the transport processes. Therefore in a second step, a two-equation turbulence model for both fluid and particle phase turbulence is derived by applying the phasic average to the instantaneous equations. The resulting k-{epsilon}-k{sup d}-{epsilon}{sup d} model is new. Mathematical closure is attempted such that the resulting set of equations is valid for both dilute arid dense flows. During the development of the closure relations a clear distinction is made between granular or ''viscous'' microscale fluctuations and turbulent macro scale fluctuations (true particle turbulence) within the particle phase. The set of governing equations is discretized by using a

  11. Modeling of dilute and dense dispersed fluid-particle flow

    Energy Technology Data Exchange (ETDEWEB)

    Laux, Harald

    1998-08-01

    A general two-fluid model is derived and applied in CFD computations to various test cases of important industrial multiphase flows. It is general in the sense of its applicability to dilute and dense dispersed fluid-particle flows. The model is limited to isothermal flow without mass transfer and only one particle phase is described. The instantaneous fluid phase equations, including the phase interaction terms, are derived from a volume averaging technique, and the instantaneous particle phase equations are derived from the kinetic theory of granular material. Whereas the averaging procedure, the treatment of the interaction terms, and the kinetic theory approach have been reported in literature prior to this work the combination of the approaches is new. The resulting equations are derived without ambiguity in the interpretation of the particle phase pressure (equation-of-state of particle phase). The basic modeling for the particle phase is improved in two steps. Because in the basic modeling only stresses due to kinetic and collisional interactions are included, a simple model for an effective viscosity is developed in order to allow also frictional stresses within the particle phase. Moreover, turbulent stresses and turbulent dispersion of particles play often an important role for the transport processes. Therefore in a second step, a two-equation turbulence model for both fluid and particle phase turbulence is derived by applying the phasic average to the instantaneous equations. The resulting k-{epsilon}-k{sup d}-{epsilon}{sup d} model is new. Mathematical closure is attempted such that the resulting set of equations is valid for both dilute arid dense flows. During the development of the closure relations a clear distinction is made between granular or ''viscous'' microscale fluctuations and turbulent macro scale fluctuations (true particle turbulence) within the particle phase. The set of governing equations is discretized by using a finite volume method

  12. How Consumers’ Styles of Thinking Can Control Brand Dilution

    Directory of Open Access Journals (Sweden)

    Monga Alokparna Basu

    2018-05-01

    Full Text Available Understanding consumers’ ways of thinking can help identify strategies to limit brand damage and elicit more favorable reactions from disapproving consumers. Analytic thinkers’ beliefs about a brand are diluted when they see negative information; those of holistic thinkers remain unaffected. While both analytic and holistic thinkers blame the brand equally for quality and manufacturing problems, holistic thinkers are more likely to blame contextual factors outside of the brand than analytic thinkers. This ability of holistic thinkers to focus on the outside context is the reason why their brand beliefs are not diluted.

  13. Computer registration of radioactive indicator-dilution curves.

    Science.gov (United States)

    Shepherd, A P; Perry, M A; Alexander, G M; Granger, D N; Riedel, G L; Kvietys, P R; Franke, C P

    1983-12-01

    A system is described for recording indicator-dilution curves produced by gamma radiation-emitting tracers. The system consists of a flow-through cuvette in a well counter, appropriate commercially available gamma radiation-detecting equipment, an Apple II computer, and a two-channel pulse-counting interface of our own design. With the counting interface and the software described here, an investigator can simultaneously record two indicator-dilution curves produced by gamma emitters. Instead of having to wait hours or days for results, the investigator can watch the data being recorded and display the results in graphic form almost immediately after each injection.

  14. GRAIN-BOUNDARY PRECIPITATION UNDER IRRADIATION IN DILUTE BINARY ALLOYS

    Institute of Scientific and Technical Information of China (English)

    S.H. Song; Z.X. Yuan; J. Liu; R.G.Faulkner

    2003-01-01

    Irradiation-induced grain boundary segregation of solute atoms frequently bring about grain boundary precipitation of a second phase because of its making the solubility limit of the solute surpassed at grain boundaries. Until now the kinetic models for irradiation-induced grain boundary precipitation have been sparse. For this reason, we have theoretically treated grain boundary precipitation under irradiation in dilute binary alloys. Predictions ofγ'-Ni3Si precipitation at grain boundaries ave made for a dilute Ni-Si alloy subjected to irradiation. It is demonstrated that grain boundary silicon segregation under irradiation may lead to grain boundaryγ'-Ni3 Si precipitation over a certain temperature range.

  15. Dilution and volatilization of groundwater contaminant discharges in streams

    DEFF Research Database (Denmark)

    Aisopou, Angeliki; Bjerg, Poul Løgstrup; Sonne, Anne Thobo

    2015-01-01

    measurement. The solution was successfully applied to published field data obtained in a large and a small Danish stream and provided valuable information on the risk posed by the groundwater contaminant plumes. The results provided by the dilution and volatilization model are very different to those obtained......An analytical solution to describe dilution and volatilization of a continuous groundwater contaminant plume into streams is developed for risk assessment. The location of groundwater plume discharge into the stream (discharge through the side versus bottom of the stream) and different...

  16. Test plan for tank 241-AN-104 dilution studies

    International Nuclear Information System (INIS)

    Herting, D.L.

    1998-01-01

    Tank 241-AN-104 (104-AN) has been identified as the one of the first tanks to be retrieved for low level waste pretreatment and immobilization. Retrieval of the tank waste will require dilution. Laboratory tests are needed to determine the amount and type of dilution required for safe retrieval and transfer of feed and to re-dissolve major soluble sodium salts while not precipitating out other salts. The proposed laboratory tests are described in this document. Tank 241-AN-104 is on the Hydrogen Watch List

  17. High field Moessbauer study of dilute Ir-(Fe) alloys

    International Nuclear Information System (INIS)

    Takabatake, Toshiro; Mazaki, Hiromasa; Shinjo, Teruya.

    1981-01-01

    The magnetic behavior of very dilute Fe impurities in Ir has been studied by means of Moessbauer measurement in external fields up to 80 kOe at 4.2 K. The saturation hyperfine field increases in proportion to the external field up to the maximum magnetic field available. This means that for a localized spin fluctuation system IrFe, the effective magnetic moment associated with Fe impurities is induced in proportion to the external field. No anomalous spectrum was observed with a very dilute sample (--10 ppm 57 Co), indicating that the interaction between impurities is responsible for the anomalous spectrum previously observed with a less homogeneous sample. (author)

  18. Introduction to the Physics of Diluted Magnetic Semiconductors

    CERN Document Server

    Gaj, Jan A

    2010-01-01

    The book deals with diluted magnetic semiconductors, a class of materials important to the emerging field of spintronics. In these materials semiconducting properties, both transport and optical, are influenced by the presence of magnetic ions. It concentrates on basic physical mechanisms (e.g. carrier-ion and ion-ion interactions) and resulting phenomena (e.g. magnetic polaron formation and spin relaxation). Introduction to the Physics of Diluted Magnetic Semiconductors is addressed to graduate-level and doctoral students and young researchers entering the field. The authors have been actively involved in the creation of this branch of semiconductor physics.

  19. Optimization of the sample dilution for minimization of the matrix effects and achieving maximal sensitivity in XRFA

    International Nuclear Information System (INIS)

    Dimov, L.; Benova, M.

    1989-01-01

    The method of neutral medium dilution can lead to practically full leveling of the matrix but the high degree of dilution at which this effect is achieved will inevitably result in loss of sensitivity. In the XRFA of heavy elements in a light matrix the dependence of the fluorescence intensity upon concentration is characterized by gradually decreasing steepness reacting saturation (as in analysis of Pb in a Pb-concentrate). The dilution by neutral medium can shift the concentration range to a zone of greater steepness but this results in an increase of sensitivity towards the concentration in the initial (undiluted) material only to a certain degree of dilution. This work presents an optimization of the degree of dilution by neutral medium which achieves a sufficient leveling of the matrix when using different materials and also maximal sensitivity towards higher concentrations. Furthermore an original solution is found to the problem of selecting a neutral medium enabling to achieve good homogenization with various materials and particularly - with marble flour. (author)

  20. Repletion of branched chain amino acids reverses mTORC1 signaling but not improved metabolism during dietary protein dilution

    DEFF Research Database (Denmark)

    Maida, Adriano; Chan, Jessica S K; Sjøberg, Kim Anker

    2017-01-01

    OBJECTIVE: Dietary protein dilution (PD) has been associated with metabolic advantages such as improved glucose homeostasis and increased energy expenditure. This phenotype involves liver-induced release of FGF21 in response to amino acid insufficiency; however, it has remained unclear whether...... dietary dilution of specific amino acids (AAs) is also required. Circulating branched chain amino acids (BCAAs) are sensitive to protein intake, elevated in the serum of obese humans and mice and thought to promote insulin resistance. We tested whether replenishment of dietary BCAAs to an AA-diluted (AAD......) diet is sufficient to reverse the glucoregulatory benefits of dietary PD. METHODS: We conducted AA profiling of serum from healthy humans and lean and high fat-fed or New Zealand obese (NZO) mice following dietary PD. We fed wildtype and NZO mice one of three amino acid defined diets: control, total...

  1. EDITORIAL: Focus on Dilute Magnetic Semiconductors FOCUS ON DILUTE MAGNETIC SEMICONDUCTORS

    Science.gov (United States)

    Chambers, Scott A.; Gallagher, Bryan

    2008-05-01

    This focus issue of New Journal of Physics is devoted to the materials science of dilute magnetic semiconductors (DMS). A DMS is traditionally defined as a diamagnetic semiconductor doped with a few to several atomic per cent of some transition metal with unpaired d electrons. Several kinds of dopant-dopant interactions can in principle couple the dopant spins leading to a ferromagnetic ground state in a dilute magnetic system. These include superexchange, which occurs principally in oxides and only between dopants with one intervening oxygen, and double exchange, in which dopants of different formal charges exchange an electron. In both of these mechanisms, the ferromagnetic alignment is not critically dependent on free carriers in the host semiconductor because exchange occurs via bonds. A third mechanism, discovered in the last few years, involves electrons associated with lattice defects that can apparently couple dopant spins. This mechanism is not well understood. Finally, the most desirable mechanism is carrier-mediated exchange interaction in which the dopant spins are coupled by itinerant electrons or holes in the host semiconductor. This mechanism introduces a fundamental link between magnetic and electrical transport properties and offers the possibility of new spintronic functionalities. In particular electrical gate control of ferromagnetism and the use of spin polarized currents to carry signals for analog and digital applications. The spin light emitting diode is a prototypical device of this kind that has been extensively used to characterize the extent of spin polarization in the active light emitting semiconductor heterostructure. The prototypical carrier mediated ferromagnetic DMS is Mn-doped GaAs. This and closely related narrow gap III-V materials have been very extensively studied. Their properties are generally quite well understood and they have led to important insights into fundamental properties of ferromagnetic systems with strong spin

  2. Improved analytical procedure for the determination of 210Pb and 210Po using alpha-spectrometric isotope dilution

    International Nuclear Information System (INIS)

    Urnezis, P.W.; Holtzman, R.B.

    1981-01-01

    An isotope dilution method has been incorporated into the 210 Pb- 210 Po analysis. A known amount of 209 Po is added to the sample before analysis. Then both 209 Po and 210 Po are deposited on a silver planchet which is assayed in an alpha spectrometer to determine the activities of each isotope. The recoveries generally range from 70% to 90%

  3. New processing techniques for radioisotopes at Oak Ridge National Laboratory; Production de radioisotopes: nouvelles techniques employees au Laboratoire national d'Oak Ridge; Novye tekhnologicheskie metody polucheniya radioizotopov v Okridzhskoj natsional'noj laboratorii; Nuevos metodos de preparacion de radioisotopos aplicados en el Oak Ridge National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Butler, T A; Lamb, E; Rupp, A F [Oak Ridge National Laboratory, Oak Ridge, TN (United States)

    1962-01-15

    Recent developments in the radioisotope production programme at Oak Ridge National Laboratory include new processes and process improvements for the production of cerium-144, promethium-147, technetium-99 and strontium-90. Cerium-144 has been produced in kc quantities in a test run. A product recovery of more than 98% with a product purity of more than 99% was attained. The cerium was further processed to obtain pure cerium-144 oxide powder having an activity concentration of 235 c/g. The powder was pressed into pellets which were sintered to a dense ceramic form. Promethium-147 has been produced in kc quantities by a combination of precipitation and ion exchange techniques. A solvent extraction system for separating promethium- 147 from other rare earths has been tested on a tracer scale. Gram quantities of technetium-99 have been recovered from fission-product waste streams by a combination of precipitation and solvent extraction processes. The technetium product was produced with a chemical purity of more than 99.9% and radiochemical purity of more than 99.99%. The separation and purification of strontium-90 from gross contaminants by a continuous solvent-extraction flowsheet has been demonstrated on a tracer scale. Product quality of 98% strontium has been achieved from feed containing 95% inert calcium contaminant. The strontium-90 is further processed to form strontium titanate ceramic elements. (author) [French] Les faits recents a noter dans le programme de production de radioisotopes du laboratoire national d'Oak Ridge sont l'introduction de nouvelles methodes et l'amelioration des techniques existantes pour la production du eerium-144, du prometheum-147, du technetium-99 et du strontium-90. Le cerium-144 a ete obtenu en quantites de l'ordre du kilocurie, lors d'une experience. On a obtenu un taux d'extraction de plus de 98% et un produit d'une purete superieure a 99%. On a ensuite traite le cerium pour avoir de l'oxyde de cerium-144 pur en poudre ayant

  4. Laminar Flame Velocity and Temperature Exponent of Diluted DME-Air Mixture

    Science.gov (United States)

    Naseer Mohammed, Abdul; Anwar, Muzammil; Juhany, Khalid A.; Mohammad, Akram

    2017-03-01

    In this paper, the laminar flame velocity and temperature exponent diluted dimethyl ether (DME) air mixtures are reported. Laminar premixed mixture of DME-air with volumetric dilutions of carbon dioxides (CO2) and nitrogen (N2) are considered. Experiments were conducted using a preheated mesoscale high aspect-ratio diverging channel with inlet dimensions of 25 mm × 2 mm. In this method, flame velocities are extracted from planar flames that were stabilized near adiabatic conditions inside the channel. The flame velocities are then plotted against the ratio of mixture temperature and the initial reference temperature. A non-linear power law regression is observed suitable. This regression analysis gives the laminar flame velocity at the initial reference temperature and temperature exponent. Decrease in the laminar flame velocity and increase in temperature exponent is observed for CO2 and N2 diluted mixtures. The addition of CO2 has profound influence when compared to N2 addition on both flame velocity and temperature exponent. Numerical prediction of the similar mixture using a detailed reaction mechanism is obtained. The computational mechanism predicts higher magnitudes for laminar flame velocity and smaller magnitudes of temperature exponent compared to experimental data.

  5. Monte Carlo study of the pure and dilute Baxter-Wu model

    International Nuclear Information System (INIS)

    Schreiber, Nir; Adler, Joan

    2005-01-01

    We studied the pure and dilute Baxter-Wu (BW) models using the Wang-Landau (WL) sampling method to calculate the density-of-states (DOS). We first used the exact result for the DOS of the Ising model to test our code. Then we calculated the DOS of the dilute Ising model to obtain a phase diagram, in good agreement with previous studies. We calculated the energy distribution, together with its first, second and fourth moments, to give the specific heat and the energy fourth order cumulant, better known as the Binder parameter, for the pure BW model. For small samples, the energy distribution displayed a doubly peaked shape, and finite size scaling analysis showed the expected reciprocal scaling of the positions of the peaks with L. The energy distribution yielded the expected BW α = 2/3 critical exponent for the specific heat. The Binder parameter minimum appeared to scale with lattice size L with an exponent θ B equal to the specific heat exponent. Its location (temperature) showed a large correction-to-scaling term θ 1 = 0.248 ± 0.025. For the dilute BW model we found a clear crossover to a single peak in the energy distribution even for small sizes and the expected α = 0 was recovered

  6. Factors to Enable Crystallization of Environmentally Stable Bioscorodite from Dilute As(III-Contaminated Waters

    Directory of Open Access Journals (Sweden)

    Masahito Tanaka

    2018-01-01

    Full Text Available Applicability of the bioscorodite method (use of the thermo-acidophilic Fe(II-oxidizing archaeon Acidianus brierleyi for arsenic (As oxidation and immobilization at 70 °C was tested for synthetic copper refinery wastewaters of a wide range of dilute initial As(III concentrations ([As(III]ini = 3.3–20 mM with varying initial [Fe(II]/[As(III] molar ratios ([Fe(II]ini/[As(III]ini = 0.8–6.0. Crystallization of scorodite (FeAsO4·2H2O tends to become increasingly challenging at more dilute As(III solutions. Optimization of conditions such as initial pH, seed feeding and initial [Fe(II]/[As(III] molar ratio was found critical in improving final As removal and product stability: Whilst setting the initial pH at 1.2 resulted in an immediate single-stage precipitation of crystalline bioscorodite, the initial pH 1.5 led to a two-stage As precipitation (generation of brown amorphous precursors followed by whitish crystalline bioscorodite particles with a greater final As removal. The formation process of bioscorodite precipitates differed significantly depending on the type of seed crystals fed (bio- versus chemical- scorodite seeds. Feeding the former was found effective not only in accelerating the reaction, but also in forming more recalcitrant bioscorodite products (0.59 mg/L; Toxicity Characteristic Leaching Procedure (TCLP test. Under such favorable conditions, 94–99% of As was successfully removed as crystalline bioscorodite at all dilute As(III concentrations tested by setting [Fe(II]ini/[As(III]ini at 1.4–2.0. Providing an excess Fe(II (closer to [Fe(II]ini/[As(III]ini = 2.0 was found beneficial to improve the final As removal (up to 98–99% especially from more dilute As(III solutions.

  7. New Insights into Butyrylcholinesterase Activity Assay: Serum Dilution Factor as a Crucial Parameter.

    Directory of Open Access Journals (Sweden)

    Joanna Jońca

    Full Text Available Butyrylcholinesterase (BChE activity assay and inhibitor phenotyping can help to identify patients at risk of prolonged paralysis following the administration of neuromuscular blocking agents. The assay plays an important role in clinical chemistry as a good diagnostic marker for intoxication with pesticides and nerve agents. Furthermore, the assay is also commonly used for in vitro characterization of cholinesterases, their toxins and drugs. There is still lack of standardized procedure for measurement of BChE activity and many laboratories use different substrates at various concentrations. The purpose of this study was to validate the BChE activity assay to determine the best dilution of human serum and the most optimal concentration of substrates and inhibitors. Serum BChE activity was measured using modified Ellman's method applicable for a microplate reader. We present our experience and new insights into the protocol for high-throughput routine assays of human plasma cholinesterase activities adapted to a microplate reader. During our routine assays used for the determination of BChE activity, we have observed that serum dilution factor influences the results obtained. We show that a 400-fold dilution of serum and 5mM S-butyrylthiocholine iodide can be successfully used for the accurate measurement of BChE activity in human serum. We also discuss usage of various concentrations of dibucaine and fluoride in BChE phenotyping. This study indicates that some factors of such a multicomponent clinical material like serum can influence kinetic parameters of the BChE. The observed inhibitory effect is dependent on serum dilution factor used in the assay.

  8. post-jomtien policy dilutions: infrastructural & quality norms

    Indian Academy of Sciences (India)

    Operation Blackboard norms diluted – from 3 teachers-3 rooms per primary school to 2 teachers-2 rooms per primary school. Regular teacher replaced by under-qualified, untrained, under-paid Para-teachers appointed on short-term contracts. EGS – No provision for school buildings or teaching aids. Multi-grade Teaching ...

  9. Coherence and stiffness of spin waves in diluted ferromagnets

    Czech Academy of Sciences Publication Activity Database

    Turek, Ilja; Kudrnovský, Josef; Drchal, Václav

    2016-01-01

    Roč. 94, č. 17 (2016), č. článku 174447. ISSN 2469-9950 R&D Projects: GA ČR GA15-13436S Institutional support: RVO:68081723 ; RVO:68378271 Keywords : spin wave s * diluted ferromagnets * disordered systems Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.836, year: 2016

  10. Procedures for accurately diluting and dispensing radioactive solutions

    International Nuclear Information System (INIS)

    1975-01-01

    The technique currently used by various laboratories participating in international comparisons of radioactivity measurements are surveyed and recommendations for good laboratory practice established. Thus one describes, for instance, the preparation of solutions, dilution techniques, the use of 'pycnometers', weighing procedures (including buyoancy correction), etc. It should be possible to keep random and systematic uncertainties below 0.1% of the final result

  11. Determination of dilution and quality control of total and anti ...

    African Journals Online (AJOL)

    Objective: To determine the correct dilution and Quality control commercial ELISA of total and anti-measles antibodies for HIV infected pregnant women. Design: A laboratory based study. Setting: The University of Nairobi, Department of Paediatrics laboratory. Subjects: HIV infected pregnant women enrolled and exposed to ...

  12. Bioethanol productions from rice polish by optimization of dilute acid ...

    African Journals Online (AJOL)

    Lignocellulose materials are abundant renewable resource for the production of biofuel from fermentative organism (Sacchromyces cervesiae). Rice polish is cheapest and abundant lignocelluloses resource and has potential to produce bioethanol. The main steps for the conversion of biomass into glucose required dilute ...

  13. Inhibition Effect of Deanol on Mild Steel Corrosion in Dilute ...

    African Journals Online (AJOL)

    NICOLAAS

    2014-06-23

    Jun 23, 2014 ... The influence of deanol on the corrosion behaviour of mild steel in dilute sulphuric acid with sodium ... the formation of a complex precipitate of protective film, which ... silicon carbide abrasive papers of 80, 120, 220, 800 and 1000 grit ...... ions in sulphuric acid on the corrosion behaviour of stainless steel,.

  14. Kinetic-sound propagation in dilute gas mixtures

    International Nuclear Information System (INIS)

    Campa, A.; Cohen, E.G.D.

    1989-01-01

    Kinetic sound is predicted in dilute disparate-mass binary gas mixtures, propagating exclusively in the light compound and much faster than ordinary sound. It should be detectable by light-scattering experiments, as an extended shoulder in the scattering cross section for large frequencies. As an example, H 2 -Ar mixtures are discussed

  15. Thermodynamics of a dilute XX chain in a field

    Energy Technology Data Exchange (ETDEWEB)

    Timonin, P. N., E-mail: pntim@live.ru [Southern Federal University, Physics Research Institute (Russian Federation)

    2016-06-15

    Gapless phases in ground states of low-dimensional quantum spin systems are rather ubiquitous. Their peculiarity is a remarkable sensitivity to external perturbations due to permanent criticality of such phases manifested by a slow (power-low) decay of pair correlations and the divergence of the corresponding susceptibility. A strong influence of various defects on the properties of the system in such a phase can then be expected. Here, we consider the influence of vacancies on the thermodynamics of the simplest quantum model with a gapless phase, the isotropic spin-1/2 XX chain. The existence of the exact solution of this model gives a unique opportunity to describe in detail the dramatic effect of dilution on the gapless phase—the appearance of an infinite series of quantum phase transitions resulting from level crossing under the variation of a longitudinal magnetic field. We calculate the jumps in the field dependences of the ground-state longitudinal magnetization, susceptibility, entropy, and specific heat appearing at these transitions and show that they result in a highly nonlinear temperature dependence of these parameters at low T. Also, the effect of enhancement of the magnetization and longitudinal correlations in the dilute chain is established. The changes of the pair spin correlators under dilution are also analyzed. The universality of the mechanism of the quantum transition generation suggests that similar effects of dilution can also be expected in gapless phases of other low-dimensional quantum spin systems.

  16. 21 CFR 172.710 - Adjuvants for pesticide use dilutions.

    Science.gov (United States)

    2010-04-01

    ... Section 172.710 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Other Specific Usage Additives § 172.710 Adjuvants for pesticide use dilutions. The...

  17. Electrochemical reduction of metal ions in dilute solution using hydrogen

    NARCIS (Netherlands)

    Portegies Zwart, I.; Wijnbelt, E.C.W.; Janssen, L.J.J.

    1995-01-01

    Reduction of metal ions in dilute solutions is of great interest for purification of waste waters and process liquids. A new electrochemical cell has been introduced. This cell - a GBC-cell - is a combination of a gasdiffusion electrode in direct contact with a packed bed of carbon particles.

  18. Electrochemical reduction of dilute chromate solutions on carbon felt electrodes

    NARCIS (Netherlands)

    Frenzel, Ines; Frenzel, I.; Holdik, Hans; Barmashenko, Vladimir; Stamatialis, Dimitrios; Wessling, Matthias

    2006-01-01

    Carbon felt is a potential material for electrochemical reduction of chromates. Very dilute solutions may be efficiently treated due to its large specific surface area and high porosity. In this work, the up-scaling of this technology is investigated using a new type of separated cell and

  19. Electrochemical reduction of nickel ions from dilute solutions

    NARCIS (Netherlands)

    Njau, K.N.; Janssen, L.J.J.

    1995-01-01

    Electrochemical reduction of nickel ions in dilute solution using a divided GBC-cell is of interest for purification of waste waters. A typical solution to be treated is the effluent from steel etching processes which contain low quantities of nickel, chromate and chromium ions. Reduction of

  20. 21 CFR 864.5240 - Automated blood cell diluting apparatus.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Automated blood cell diluting apparatus. 864.5240 Section 864.5240 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Automated and Semi-Automated Hematology Devices...

  1. Analysis of boron dilution in a four-loop PWR

    International Nuclear Information System (INIS)

    Sun, J.G.; Sha, W.T.

    1995-03-01

    Thermal mixing and boron dilution in a pressurized water reactor were analyzed with COMMIX codes. The reactor system was the four-loop Zion reactor. Two boron dilution scenarios were analyzed. In the first scenario, the plant is in cold shutdown and the reactor coolant system has just been filled after maintenance on the steam generators. To flush the air out of the steam generator tubes, a reactor coolant pump (RCP) is started, with the water in the pump suction line devoid of boron and at the same temperature as the coolant in the system. In the second scenario, the plant is at hot standby and the reactor coolant system has been heated to operating temperature after a long outage. It is assumed that an RCP is started, with the pump suction line filled with cold unborated water, forcing a slug of diluted coolant down the downcomer and subsequently through the reactor core. The subsequent transient thermal mixing and boron dilution that would occur in the reactor system is simulated for these two scenarios. The reactivity insertion rate and the total reactivity are evaluated and a sensitivity study is performed to assess the accuracy of the numerical modeling of the geometry of the reactor coolant system

  2. Optimisation of Dilute Sulphuric Acid Hydrolysis of Waste ...

    African Journals Online (AJOL)

    Dilute sulphuric acid hydrolysis of waste paper was investigated in this study. The effects of acid concentration, time, temperature and liquid to solid ratio on the total reducing sugar concentration were studied over three levels using a four variable Box-Behnken design (BBD). A statistical model was developed for the ...

  3. Atomic displacements in dilute alloys of Cr, Nb and Mo

    Indian Academy of Sciences (India)

    physics pp. 497–514. Atomic displacements in dilute alloys of Cr, Nb and Mo ... used to calculate dynamical matrix and the impurity-induced forces up to second nearest ... origin, the lattice is strained, and the host atoms get displaced to new ...

  4. Color dilution alopecia in a blue Doberman pinscher crossbreed

    OpenAIRE

    Perego, Roberta; Proverbio, Daniela; Roccabianca, Paola; Spada, Eva

    2009-01-01

    A 6-year-old male, blue Doberman pinscher crossbreed was presented with coat abnormalities; in particular, flank alopecia and pruritus. Based on medical the history, clinical evidence, and histopathological examination, color dilution alopecia was diagnosed. The dog was with oral melatonin treated for 3 months without success.

  5. Color dilution alopecia in a blue Doberman pinscher crossbreed.

    Science.gov (United States)

    Perego, Roberta; Proverbio, Daniela; Roccabianca, Paola; Spada, Eva

    2009-05-01

    A 6-year-old male, blue Doberman pinscher crossbreed was presented with coat abnormalities; in particular, flank alopecia and pruritus. Based on medical the history, clinical evidence, and histopathological examination, color dilution alopecia was diagnosed. The dog was with oral melatonin treated for 3 months without success.

  6. Does the dilution effect generally occur in animal diseases?

    NARCIS (Netherlands)

    Huang, Zheng Y.X.; Yu, Yang; Langevelde, Van Frank; Boer, De Willem F.

    2017-01-01

    The dilution effect (DE) has been reported in many diseases, but its generality is still highly disputed. Most current criticisms of DE are related to animal diseases. Particularly, some critical studies argued that DE is less likely to occur in complex environments. Here our meta-analyses

  7. Inhibition Effect of Deanol on Mild Steel Corrosion in Dilute ...

    African Journals Online (AJOL)

    The influence of deanol on the corrosion behaviour of mild steel in dilute sulphuric acid with sodium chloride addition was studied by means of mass-loss, potentiodynamic polarization, electrode potential monitoring, scanning electron microscopy and statistical analysis. Results show that deanol performed excellently with ...

  8. Novel understanding of calcium silicate hydrate from dilute hydration

    KAUST Repository

    Zhang, Lina; Yamauchi, Kazuo; Li, Zongjin; Zhang, Xixiang; Ma, Hongyan; Ge, Shenguang

    2017-01-01

    The perspective of calcium silicate hydrate (C-S-H) is still confronting various debates due to its intrinsic complicated structure and properties after decades of studies. In this study, hydration at dilute suspension of w/s equaling to 10

  9. Piglets produced by transfer of vitrified porcine embryos after stepwise dilution of cryoprotectants.

    Science.gov (United States)

    Kobayashi, S; Takei, M; Kano, M; Tomita, M; Leibo, S P

    1998-02-01

    A total of 498 porcine embryos at various stages of development collected from superovulated gilts was used to investigate cryopreservation. First, blastocysts (BL), expanded blastocysts (ExB), and hatched blastocysts (HB) were used to determine the effect of exposure to concentrated solutions of ethylene glycol as cryoprotective additives (CPAs) on embryo survival. Then, survival of other embryos after vitrification by rapid cooling was determined. Based on their development after 48 h in culture, embryos were not injured by being exposed to 2.0 M ethylene glycol (EG) for 15 min or to 2.0 M EG for 5 min and then to a solution of 8.0 M EG in 7% polyvinylpyrrolidone (PVP) for 1 min. The CPAs were removed from the embryos by diluting them with 1.7 M galactose. To vitrify the embryos, they were exposed to 2.0 M EG for 5 min and then were pipetted directly into short columns of 8.0 M EG-PVP contained within (1.25-ml plastic straws and separated from long columns of 1.7 M galactose by an air bubble. The straws were plunged directly into LN2. After the straws were warmed rapidly in a 25 degrees C water bath, the embryos were immediately mixed with galactose within the straws by shaking them vigorously to mix the contents. In sequential experiments, three methods were used to dilute the CPA solutions. Method 1: Embryos in the EG-PVP-galactose mixture were expelled from the straws and rinsed and cultured in modified CZB medium (mCZB). Method II: Embryos in the mixture were placed briefly into 1.5 M EG and then rinsed and cultured in mCZB. Method III: Embryos in the mixture were rinsed in 1.0 M EG and then in 0.5 M EG and finally rinsed with mCZB and cultured. After 48 h in culture, the respective percentages of survival of embryos vitrified as BL, ExB, or HB were: Method I, 21, 32, and 13%; Method II, 9, 40, and 24%; Method III, 35, 85, and 71%. Of 20 additional ExB vitrified embryos diluted by Method III and transferred into a recipient, four developed into live piglets

  10. Isolation of previously uncultured rumen bacteria by dilution to extinction using a new liquid culture medium.

    Science.gov (United States)

    Kenters, Nikki; Henderson, Gemma; Jeyanathan, Jeyamalar; Kittelmann, Sandra; Janssen, Peter H

    2011-01-01

    A new anaerobic medium that mimics the salts composition of rumen fluid was used in conjunction with a dilution method of liquid culture to isolate fermentative bacteria from the rumen of a grass-fed sheep. The aim was to inoculate a large number of culture tubes each with a mean of 97% sequence identity to genes of uncultured bacteria detected in various gastrointestinal environments. This strategy has therefore allowed us to cultivate many novel rumen bacteria, opening the way to overcoming the lack of cultures of many of the groups detected using cultivation-independent methods. Copyright © 2010 Elsevier B.V. All rights reserved.

  11. Sugar yields from dilute oxalic acid pretreatment of maple wood compared to those with other dilute acids and hot water.

    Science.gov (United States)

    Zhang, Taiying; Kumar, Rajeev; Wyman, Charles E

    2013-01-30

    Dilute oxalic acid pretreatment was applied to maple wood to improve compatibility with downstream operations, and its performance in pretreatment and subsequent enzymatic hydrolysis was compared to results for hydrothermal and dilute hydrochloric and sulfuric acid pretreatments. The highest total xylose yield of ∼84% of the theoretical maximum was for both 0.5% oxalic and sulfuric acid pretreatment at 160 °C, compared to ∼81% yield for hydrothermal pretreatment at 200 °C and for 0.5% hydrochloric acid pretreatment at 140 °C. The xylooligomer fraction from dilute oxalic acid pretreatment was only 6.3% of the total xylose in solution, similar to results with dilute hydrochloric and sulfuric acids but much lower than the ∼70% value for hydrothermal pretreatment. Combining any of the four pretreatments with enzymatic hydrolysis with 60 FPU cellulase/g of glucan plus xylan in the pretreated maple wood resulted in virtually the same total glucose plus xylose yields of ∼85% of the maximum possible. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Total cholesterol in serum determined by isotope dilution/mass spectrometry, with liquid-chromatographic separation

    International Nuclear Information System (INIS)

    Takatsu, Akiko; Nishi, Sueo

    1988-01-01

    We describe an accurate, precise method for determination of total serum cholesterol by isotope dilution/mass spectrometry (IDMS) with liquid chromatographic separation. After adding [3,4- 13 C] cholesterol to serum and hydrolyzing the cholesterol esters, we extract the total cholesterol. High-performance liquid chromatography (HPLC) is used to separate the extracted cholesterol for measurement by electron-impact mass spectrometry with use of a direct-insertion device. To evaluate the specificity and the accuracy of this method, we also studied the conventional IDMS method, which involves converting cholesterol to the trimethylsilyl ether and assay by gas chromatography-mass spectrometry with use of a capillary column. The coefficient of variation for the HPLC method was a little larger than for the conventional method, but mean values by each method agreed within 1% for all sera tested. (author)

  13. Activity coefficients at infinite dilution and enthalpies of solution of methanol, 1-butanol, and 1-hexanol in 1-hexyl-3-methyl-imidazolium bis(trifluoromethyl-sulfonyl) imide

    International Nuclear Information System (INIS)

    Heintz, Andreas; Verevkin, Sergey P.; Lehmann, Jochen K.; Vasiltsova, Tatiana V.; Ondo, Daniel

    2007-01-01

    Activity coefficients at infinite dilution γ i ∼ of methanol, 1-butanol, and 1-hexanol in the ionic liquid 1-hexyl-3-methyl-imidazolium bis(trifluoromethyl-sulfonyl) imide ([HMIM][NTf 2 ]) have been determined by gas chromatography using the ionic liquids as stationary phase. The measurements were carried out at different temperatures between 298K and 396K. From the temperature dependence of the limiting activity coefficients partial molar excess enthalpies at infinite dilution H i E,∼ of the alcohol in the ionic liquid have been derived. Additionally, enthalpies of solution of the same alcohols in the [HMIM][NTf 2 ] have been measured at T=298.15K in the range of low concentrations using titration calorimetry. Results at infinite dilution, H i E,∼ , are compared with those indirectly obtained from activity coefficients in infinite dilution γ i ∼ . Within the experimental error of both methods thermodynamic consistency has been confirmed

  14. Transverse emittance dilution due to coupler kicks in linear accelerators

    Directory of Open Access Journals (Sweden)

    Brandon Buckley

    2007-11-01

    Full Text Available One of the main concerns in the design of low emittance linear accelerators (linacs is the preservation of beam emittance. Here we discuss one possible source of emittance dilution, the coupler kick, due to transverse electromagnetic fields in the accelerating cavities of the linac caused by the power coupler geometry. In addition to emittance growth, the coupler kick also produces orbit distortions. It is common wisdom that emittance growth from coupler kicks can be strongly reduced by using two couplers per cavity mounted opposite each other or by having the couplers of successive cavities alternate from above to below the beam pipe so as to cancel each individual kick. While this is correct, including two couplers per cavity or alternating the coupler location requires large technical changes and increased cost for superconducting cryomodules where cryogenic pipes are arranged parallel to a string of several cavities. We therefore analyze consequences of alternate coupler placements. We show here that alternating the coupler location from above to below compensates the emittance growth as well as the orbit distortions. For sufficiently large Q values, alternating the coupler location from before to after the cavity leads to a cancellation of the orbit distortion but not of the emittance growth, whereas alternating the coupler location from before and above to behind and below the cavity cancels the emittance growth but not the orbit distortion. We show that cancellations hold for sufficiently large Q values. These compensations hold even when each cavity is individually detuned, e.g., by microphonics. Another effective method for reducing coupler kicks that is studied is the optimization of the phase of the coupler kick so as to minimize the effects on emittance from each coupler. This technique is independent of the coupler geometry but relies on operating on crest. A final technique studied is symmetrization of the cavity geometry in the

  15. Individual Tracer Atoms in an Ultracold Dilute Gas

    Science.gov (United States)

    Hohmann, Michael; Kindermann, Farina; Lausch, Tobias; Mayer, Daniel; Schmidt, Felix; Lutz, Eric; Widera, Artur

    2017-06-01

    We report on the experimental investigation of individual Cs atoms impinging on a dilute cloud of ultracold Rb atoms with variable density. We study the relaxation of the initial nonthermal state and detect the effect of single collisions which has so far eluded observation. We show that, after few collisions, the measured spatial distribution of the tracer atoms is correctly described by a Langevin equation with a velocity-dependent friction coefficient, over a large range of Knudsen numbers. Our results extend the simple and effective Langevin treatment to the realm of light particles in dilute gases. The experimental technique developed opens up the microscopic exploration of a novel regime of diffusion at the level of individual collisions.

  16. Husimi-cactus approximation study on the diluted spin ice

    Science.gov (United States)

    Otsuka, Hiromi; Okabe, Yutaka; Nefedev, Konstantin

    2018-04-01

    We investigate dilution effects on the classical spin-ice materials such as Ho2Ti2O7 and Dy2Ti2O7 . In particular, we derive a formula of the thermodynamic quantities as functions of the temperature and a nonmagnetic ion concentration based on a Husimi-cactus approximation. We find that the formula predicts a dilution-induced crossover from the cooperative to the conventional paramagnets in a ground state, and that it also reproduces the "generalized Pauling's entropy" given by Ke et al. To verify the formula from a numerical viewpoint, we compare these results with Monte Carlo simulation calculation data, and then find good agreement for all parameter values.

  17. Mössbauer Studies of dilute Magnetic Semiconductors

    CERN Multimedia

    Gislason, H P; Debernardi, A; Dlamini, W B

    2002-01-01

    The recent discovery of (dilute) magnetic semiconductors with wide band gaps, e.g. GaN, ZnO and other oxides, having Curie temperatures, T$_{\\textrm{c}}$, well above room temperature, has prompted extraordinary experimental and theoretical efforts to understand, control and exploit this unexpected finding not least in view of the obvious potential of such materials for the fabrication of "spin-(elec)tronic" or magneto-optic devices. Ferromagnetism (FM) was achieved mostly by doping with dilute 3d transition metal impurities, notably Mn, Fe, and Co (in \\% concentrations), during growth or by subsequent ion implantation. However, it is fair to state that experimentally the conditions for the occurrence of ferro-, antiferro- or paramagnetism with these impurities are not yet controlled as generally at least two conflicting forms of magnetism or none have been reported for each system - albeit often produced by different techniques. Theory is challenged as "conventional" models seem to fail and no generally accep...

  18. Further development of IDGS: Isotope dilution gamma-ray spectrometry

    International Nuclear Information System (INIS)

    Li, T.K.; Parker, J.L.; Kuno, Y.; Sato, S.; Kamata, M.; Akiyama, T.

    1991-01-01

    The isotope dilution gamma-ray spectrometry (IDGS) technique for determining the plutonium concentration and isotopic composition of highly radioactive spent-fuel dissolver solutions has been further developed. Both the sample preparation and the analysis have been improved. The plutonium isotopic analysis is based on high-resolution, low-energy gamma-ray spectrometry. The plutonium concentration in the dissolver solutions then is calculated from the measured isotopic differences among the spike, the dissolver solution, and the spiked dissolver solution. Plutonium concentrations and isotopic compositions of dissolver solutions analyzed from this study agree well with those obtained by traditional isotope dilution mass spectrometry (IDMS) and are consistent with the first IDGS experimental result. With the current detector efficiency, sample size, and a 100-min count time, the estimated precision is ∼0.5% for 239 Pu and 240 Pu isotopic analyses and ∼1% for the plutonium concentration analysis. 5 refs., 2 figs., 7 tabs

  19. Sibship Size and Gendered Resource Dilution in Different Societal Contexts.

    Directory of Open Access Journals (Sweden)

    Matthijs Kalmijn

    Full Text Available Resource dilution theory hypothesizes that children's educational attainment suffers from being raised with many siblings, as the parental resources have to be shared with more children. Based on economic and cultural theories, we hypothesize that resource dilution is gendered: especially a larger number of brothers is harmful to a person's educational attainment. Using the Survey of Health, Ageing and Retirement in Europe, covering 18 European countries, we show that the number of brothers is more negatively related with the odds of obtaining a college degree than the number of sisters. This holds particularly for women. However, this pattern is weaker in countries that are known to have a more gender-egalitarian climate.

  20. The development and site investigation of fume diluter

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Bok Youn; Kang, Chang Hee; Jo, Young Do; Lim, Sang Taek [Korea Institute of Geology Mining and Materials, Taejon (Korea, Republic of)

    1996-12-01

    It is third project year on `Application of mobile diesel equipment in underground mines` for providing appropriate measures to improve underground working environment contaminated by the diesel exhaust pollutants. For reducing the exhaust temperature bellow 70 deg. C to prevent production of the governing pollutant (NO{sub 2}), the fume diluter is verified the most effective device through the site investigation. Therefore, the fume diluter is strongly recommended instead of catalytic converter which is employed presently. The performances derived from the tests are as follows; 1) This device increased air flow to 6.7-8.4 times of the original exhaust, 2) Exhaust temperature can be reduced to 66 deg. C from 161 deg. C, 3) All the pollutants can be reduced to bellow than 30 % of exhaust concentration, 4) This device requires less cost and no maintenance. (author). 4 tabs., 4 figs.

  1. Critical mass variation of 239Pu with water dilution

    International Nuclear Information System (INIS)

    Pearlstein, S.

    1996-01-01

    The critical mass of an unreflected solid sphere of 239 Pu is ∼ 10 kg. The increase in critical mass observed for small water dilutions of unreflected 239 Pu spheres is paradoxical. Introducing small amounts of water uniformly throughout the sphere increases the spherical volume containing the same amount of 239 Pu as the critical solid sphere. The increase in radius decreases the surface-to-volume ratio of the sphere, which has the effect to first order of decreasing the neutron leakage, which is proportional to the surface, relative to the fissions, which are proportional to the volume. The reduction in neutron leakage is expected to reduce the critical mass, but instead, the critical mass is observed to increase. It is discussed how changes in the fast neutron spectrum with corresponding changes in the nuclear parameters result in an increase in critical mass for small water dilutions

  2. Percolation of polyatomic species on site diluted lattices

    International Nuclear Information System (INIS)

    Cornette, V.; Ramirez-Pastor, A.J.; Nieto, F.

    2006-01-01

    In this Letter, the percolation of (a) linear segments of size k and (b) k-mers (particles occupying k adjacent sites) of different structures and forms deposited on a diluted square lattice have been studied. The diluted lattice is built by randomly selecting a fraction of sites which are considered forbidden for deposition. The analysis of the obtained results is made in the framework of the finite size scaling theory. The characteristic parameters of the percolation problem are dependent not only on the form and structure of the k-mers but also on the properties of the lattice where they are deposited. A phase diagram separating a percolating from a non-percolating region is determined and discussed

  3. Exchange bias in diluted-antiferromagnet/antiferromagnet bilayers

    International Nuclear Information System (INIS)

    Mao, Zhongquan; Zhan, Xiaozhi; Chen, Xi

    2015-01-01

    The hysteresis-loop properties of a diluted-antiferromagnetic (DAF) layer exchange coupling to an antiferromagnetic (AF) layer are investigated by means of numerical simulations. Remarkable loop shift and coercivity enhancement are observed in such DAF/AF bilayers, while they are absent in the uncoupled DAF single layer. The influences of pinned domains, dilution, cooling field and DAF layer thickness on the loop shift are investigated systematically. The result unambiguously confirms an exchange bias (EB) effect in the DAF/AF bilayers. It also reveals that the EB effect originates from the pinned AF domains within the DAF layer. In contrast to conventional EB systems, frozen uncompensated spins are not found at the interface of the AF pinning layer. (paper)

  4. A model for the viscosity of dilute smectite gels

    International Nuclear Information System (INIS)

    Liu, L.

    2011-01-01

    A simple yet accurate model describing the viscosity of dilute suspensions of sodium montmorillonite in dilute homo-ionic solutions is presented. Taking the clay particle and the surrounding clouds of ions as a whole as an uncharged but soft, coin-like particle, the Huggins' equation for a suspension of uncharged particles is extended in the model to account for not only the primary and the secondary electro-viscous effects, but also the multi-particle interaction. The agreements between the predicted and measured results are excellent. The Huggins' coefficient obtained compares favorably with available data, while the intrinsic viscosity reduces to the Simha's equation in the large limit of ionic strength, suggesting that the model is robust. (authors)

  5. Radioisotope dilution technique for determination of vitamin B12 in foods

    International Nuclear Information System (INIS)

    Casey, P.J.; Speckman, K.R.; Ebert, F.J.; Hobbs, W.E.

    1982-01-01

    A radioisotope dilution (RID) method for the determination of vitamin B 12 is presented. The method combines a standard extraction procedure (AOAC 43.108, 12th ed.) with a commercially available RID assay kit. The method was evaluated on a wide range of fortified and unfortified food products. Recovery studies on both groups yielded average recoveries of 98.1 and 95.8%, respectively. Reproducibility data generated from replicate analysis on both groups gave a relative standard deviation of 6.9% for the fortified group and 9.2% for the unfortified group. For the samples studied, the mean vitamin B 12 content determined by the RID method was 8.01 μ/100 g vs a mean of 7.54 μg/100 g by the AOAC microbiological method; the correlation coefficient was r = 0.983

  6. Flow parameter determination in pneumatic dilute phase flow applications; Foerderparameterbestimmung in pneumatischen Duennstrom-Transportanwendungen

    Energy Technology Data Exchange (ETDEWEB)

    Fuchs, A.; Zangl, H.; Brasseur, G. [Technische Univ. Graz (Austria). Inst. fuer Elektrische Messtechnik und Messsignalverarbeitung

    2007-07-01

    This paper investigates possible approaches towards the development of a flowmeter that allows the determination of the material velocity and the material concentration in pneumatically conveyed bulk solids. These two flow parameters yield the mass flow of material through the conveyor pipe. Measurement methods and sensor principles that satisfy requirements for the flowmeter have been realized as prototype-sensors and were tested in practical dilute phase conveying applications. In particular, the development and the application of optical principles, of a sensor based on spatial filtering, and a capacitive cross-correlation sensor are addressed in the present work. (orig.)

  7. Elimination of slightly radioactive liquid effluent by dilution. Its consequences (1960)

    International Nuclear Information System (INIS)

    Bovard, P.; Candillon, C.

    1960-01-01

    Nuclear centres often have to solve problems raised by the elimination of large volumes of slightly radioactive liquid effluent. As things stand at present, the method usually adopted consists in expelling this effluent into the main water system in order to dilute it to a maximum, and thus to lower its radioactive isotope concentration to below the norms imposed by the Public Health Service. This technique requires systematic checking of the water system and its dependences, and demands a thorough knowledge of adsorption and fixation processes. (author) [fr

  8. Field ionization mass spectrometry (FIMS) applied to tracer studies and isotope dilution analysis

    International Nuclear Information System (INIS)

    Anbar, M.; Heck, H.d'A.; McReynolds, J.H.; St John, G.A.

    1975-01-01

    The nonfragmenting nature of field ionization mass spectrometry makes it a preferred technique for the isotopic analysis of multilabeled organic compounds. The possibility of field ionization of nonvolatile thermolabile materials significantly extends the potential uses of this technique beyond those of conventional ionization methods. Multilabeled tracers may be studied in biological systems with a sensitivity comparable to that of radioactive tracers. Isotope dilution analysis may be performed reliably by this technique down to picogram levels. These techniques will be illustrated by a number of current studies using multilabeled metabolites and drugs. The scope and limitations of the methodology are discussed

  9. Syrie–Liban: intégration régionale ou dilution?

    Directory of Open Access Journals (Sweden)

    Fabrice Balanche

    2005-09-01

    Full Text Available Since their separate independence in 1945, relations between Lebanon and Syria have always been conflictual, because Syrian nationalism never fully accepted that «territorial amputation». Border closures, political pressure and military occupation were the methods used to keep Lebanon on a tight rein. The Syrian occupation, officialised by the Taif Accords of 1989, led to economic and political integration between Syria and Lebanon, which generated dilution. The Syrian withdrawal in spring 2005 interrupted that process, without giving Lebanon full emancipation from its neighbour.

  10. The measurement of water vapor permeability of glove materials using dilute tritiated water

    International Nuclear Information System (INIS)

    Doughty, D.H.

    1982-01-01

    As fusion technology progresses, there will be an increasing need to handle tritium and tritiated compounds. Protective clothing, especially drybox gloves, must be an effective barrier to minimize worker exposure. The water vapor permeability of glove materials and finished glove constructions is a crucial property of drybox gloves and is not sufficiently well characterized. We have built an apparatus that measures water vapor permeability of elastomers using dilute tritiated water. The technique is more sensitive than other methods currently available and allows us to make measurements on materials and under conditions previously inaccessible. In particular, we present results on laminated drybox gloves for which data is not currently available. (orig.)

  11. Novel Dilute Bismide, Epitaxy, Physical Properties and Device Application

    Directory of Open Access Journals (Sweden)

    Lijuan Wang

    2017-02-01

    Full Text Available Dilute bismide in which a small amount of bismuth is incorporated to host III-Vs is the least studied III-V compound semiconductor and has received steadily increasing attention since 2000. In this paper, we review theoretical predictions of physical properties of bismide alloys, epitaxial growth of bismide thin films and nanostructures, surface, structural, electric, transport and optic properties of various binaries and bismide alloys, and device applications.

  12. Electron paramagnetic resonance studies of defects in dilute magnetic alloys

    International Nuclear Information System (INIS)

    Suss, J.T.; Raizman, A.

    1980-01-01

    The EPR spectrum of erbium was used to study the effects of cold-working (rolling and mechanical polishing) in dilute gold-erbium alloys. Variation in the EPR linewidth, intensity and asymmetry parameter (A/B ratio) were investigated. Most of the results could be interpreted in terms of segregation of erbium ions to subgrain boundaries (dislocations) in a surface layer of a few thousand Angstroms. (author)

  13. Water Stress Scatters Nitrogen Dilution Curves in Wheat

    Directory of Open Access Journals (Sweden)

    Marianne Hoogmoed

    2018-04-01

    Full Text Available Nitrogen dilution curves relate a crop’s critical nitrogen concentration (%Nc to biomass (W according to the allometric model %Nc = a W-b. This model has a strong theoretical foundation, and parameters a and b show little variation for well-watered crops. Here we explore the robustness of this model for water stressed crops. We established experiments to examine the combined effects of water stress, phenology, partitioning of biomass, and water-soluble carbohydrates (WSC, as driven by environment and variety, on the %Nc of wheat crops. We compared models where %Nc was plotted against biomass, growth stage and thermal time. The models were similarly scattered. Residuals of the %Nc - biomass model at anthesis were positively related to biomass, stem:biomass ratio, Δ13C and water supply, and negatively related to ear:biomass ratio and concentration of WSC. These are physiologically meaningful associations explaining the scatter of biomass-based dilution curves. Residuals of the thermal time model showed less consistent associations with these variables. The biomass dilution model developed for well-watered crops overestimates nitrogen deficiency of water-stressed crops, and a biomass-based model is conceptually more justified than developmental models. This has implications for diagnostic and modeling. As theory is lagging, a greater degree of empiricism might be useful to capture environmental, chiefly water, and genotype-dependent traits in the determination of critical nitrogen for diagnostic purposes. Sensitivity analysis would help to decide if scaling nitrogen dilution curves for crop water status, and genotype-dependent parameters are needed.

  14. Thermomechanical Processing of Structural Steels with Dilute Niobium Additions

    Science.gov (United States)

    Cui, Z.; Patel, J.; Palmiere, E. J.

    The recrystallisation behaviour of medium carbon steels with dilute Nb addition was investigated by means of plane strain compression tests and the observation of prior austenite microstructures during different deformation conditions. It was found that complete suppression of recrystallisation did not occur in the deformation temperature range investigated. At lower deformation temperatures, partial recrystallisation occurred in the higher Nb sample. This gives the potential to obtain a full suppression of recrystallisation at lower deformation temperatures.

  15. Removal of sulfite liquor from digesters with partially diluted liquor

    Energy Technology Data Exchange (ETDEWEB)

    Leshchenko, I G; Sykol, V P

    1957-01-01

    The yield of reducing sugars was raised from 189 to 224 kg/ton of pulp by displacing the cooking liquor with diluted liquor. As the pressure during blow-off dropped to 3.5-3.0 atmosphere, weak sulfite liquor was added at the rate 120 cu m/hr. After 5-10 minutes the liquor was pumped from the digester to the ethanol plant.

  16. Learning and forgetting on asymmetric, diluted neural networks

    International Nuclear Information System (INIS)

    Derrida, B.; Nadal, J.P.

    1987-01-01

    It is possible to construct diluted asymmetric models of neural networks for which the dynamics can be calculated exactly. The authors test several learning schemes, in particular, models for which the values of the synapses remain bounded and depend on the history. Our analytical results on the relative efficiencies of the various learning schemes are qualitatively similar to the corresponding ones obtained numerically on fully connected symmetric networks

  17. Review of the {sup 60}Co Source. Development Program at Brookhaven National Laboratory; Le Programme de Mise au Point des Sources au {sup 60}Co au Laboratoire National de Brookhaven; Obzor programmy po razrabotke istochnikov {sup 60}Co v brukkhejvenskoj natsional'noj laboratorii; El Programa de Preparacion de Fuentes de {sup 60}Co del Laboratorio Nacional de Brookhaven

    Energy Technology Data Exchange (ETDEWEB)

    Kuhl, O. A. [Brookhaven National Laboratory, Upton, NY (United States)

    1966-11-15

    Early in the 1950's, at the request of the United States Atomic Energy Commission, Brookhaven National Laboratory (BNL) undertook the development of radiation sources. These sources were mainly of two types: large tubes, and flat strips. Initially these were used for research at BNL. Later, other institutions were permitted to use the irradiation facilities designed for these sources. As interest grew, source-irradiator combinations were made available to other researchers. Shipping containers for sources were developed. Small hot cells and water-filled pools were constructed to utilize the sources. Methods of dosimetry, curie evaluation, and irradiator design for these sources are discussed in this paper. During the research stages, economics were not usually important; however, the trend toward large- scale radiation processing in the field of food, chemicals and medical supplies will require careful consideration of the technical and economic aspects of source design. The development of the BNL Standard Mark I and Mark II Sources, already in use in a number of' facilities, is to satisfy these important requirements. The Mark I and Mark II sources are interchangeable. An improvement in the Mark II element design is that the inner cladding is metallurgically bonded to the cobalt core. It is now possible, for the first time, to reactivate these source elements after a period of use. Individual strips are sized for easy arrangement in plaques of various dimensions and shapes. The design philosophy, fabrication techniques, and test procedures, together with source analysis and curie evaluation, are described. Comparisons are made with other source types currently in use and economical and technical advantages are discussed. (author) [French] A la demande de la Commission de l'energie atomique des Etats-Unis, le Laboratoire national de Brookhaven a entrepris des les annees 50 la mise au point de sources de rayonnement. Ces sources etaient principalement de deux types

  18. Regional lung deposition of aged and diluted sidestream tobacco smoke

    International Nuclear Information System (INIS)

    Hofmann, W; Winkler-Heil, R; McAughey, J

    2009-01-01

    Since aged and diluted smoke particles are in general smaller and more stable than mainstream tobacco smoke, it should be possible to model their deposition on the basis of their measured particle diameters. However in practice, measured deposition values are consistently greater than those predicted by deposition models. Thus the primary objective of this study was to compare theoretical predictions obtained by the Monte Carlo code IDEAL with two human deposition studies to attempt to reconcile these differences. In the first study, male and female volunteers inhaled aged and diluted sidestream tobacco smoke at two steady-state concentrations under normal tidal breathing conditions. In the second study, male volunteers inhaled aged and diluted sidestream smoke labelled with 212 Pb to fixed inhalation patterns. Median particle diameters in the two studies were 125 nm (CMD) and 210 nm (AMD), respectively. Experimental data on total deposition were consistently higher than the corresponding theoretical predictions, exhibiting significant inter-subject variations. However, measured and calculated regional deposition data are quite similar to each other, except for the extra-thoracic region. This discrepancy suggests that either the initial particle diameter decreases upon inspiration and/or additional deposition mechanisms are operating in the case of tobacco smoke particles.

  19. Novel aspects of diluted and digital magnetic heterostructures

    International Nuclear Information System (INIS)

    Bonanni, A.

    1999-04-01

    In the present work novel aspects of diluted and digital II-VI-based heterostructures containing Mn ions are investigated. All the structures under study were fabricated by means of molecular beam epitaxy. Digital magnetic heterostructures have been prepared by incorporating discrete (sub)monolayers of the purely magnetic semiconductor MnTe into otherwise non magnetic CdTe quantum wells embedded in CdMgTe barriers. Formation and binding energy of magnetic polarons have been investigated in these structures and compared with the diluted case. Reflectance difference spectroscopy (RDS) performed ex-situ allowed to distinguish between signals due to the crystal anisotropy solely and those induced by the presence a magnetic elements. The problem of p-type doping of bulk diluted magnetic semiconductors II-VI-based is tackled. During and upon growth of ZnMnTe highly doped with N, in-situ RDS was carried out in order to investigate intra-ion transitions within the half filled 3d shell of Mn. Transport measurements and magnetometry at low temperature were performed to study, on the tracks of recent theoretical works, the influence of free carriers on the interaction between magnetic ions. As expected, indications of ferromagnetic ordering were found for the DMS with the highest concentration of carriers. Special attention was given to the formation of Mn islands on a II-VI substrate and to their change in morphology upon overgrowth with a mismatched material. A rich zoology of regularly shaped nanostructures could be produced. (author)

  20. Pollutant Dilution and Diffusion in Urban Street Canyon Neighboring Streets

    Science.gov (United States)

    Sun, Z.; Fu, Zh. M.

    2011-09-01

    In the present study we investigated the airflow patterns and air quality of a series of typical street canyon combinations, developed a mass balance model to determine the local pollutant dilution rate, and discuss the impact of upstream canyon on the air quality of downstream canyon. The results indicated that the geometrical size of upstream and downstream buildings have significant impacts on the ambient airflow patterns. The pollution distribution within the canyons varies with different building combinations and flow patterns. Within the upstream canyon, pollution always accumulates to the low building side for non-symmetrical canyon, and for symmetrical canyon high level of pollution occurs at the leeward side. The height of the middle and downstream buildings can evidently change the pollutant dispersion direction during the transport process. Within the polluted canyon, the pollutant dilution rate (PDR) also varies with different street canyon combinations. The highest PDR is observed when the upstream buildings are both low buildings no matter the height of downstream building. However, the two cases are likely to contribution pollution to the downstream canyon. The H-L-H combination is mostly against local pollution remove, while the L-H-L case is considered the best optimistic building combination with both the ability of diluting local pollution and not remarkably decreasing air quality of downstream canyon. The current work is expected instructive for city designers to optimize traffic patterns under typical existing geometry or in the development of urban geometry modification for air quality control.

  1. The issue of risk dilution in risk assessments

    International Nuclear Information System (INIS)

    Wilmot, R.; Robinson, P.

    2004-01-01

    This paper explores an issue that was first highlighted more than 20 years ago during an inquiry concerning the Sizeweli B nuclear power station in the UK. In the probabilistic safety assessment for this plant, the proponent had apparently reduced its estimates of risk by admitting to increased uncertainty about the timing of certain events. This situation is counter-intuitive, since an increase in uncertainty about the factors contributing to safety would be expected to lead to less confidence and hence to greater risk. This paradoxical situation was termed 'risk dilution' and it has been a topic of interest to reviewers of safety cases since. The recent international peer review of the Yucca Mountain performance assessments concluded that there was a potential for risk dilution in the assumptions and calculations presented. The next section describes how assumptions about the timing of events and other aspects of an assessment may lead to risk dilution, and this is followed by two examples based on recent performance assessments. The final section discusses how potential problems can be identified in safety cases, and the types of response that a regulator might adopt as a result. (authors)

  2. Physical modelling of a rapid boron dilution transient

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, N.G.; Hemstroem, B.; Karlsson, R. [Vattenfall Utveckling AB, Aelvkarleby (Sweden); Jacobson, S. [Vattenfall AB, Ringhals, Vaeroebacka (Sweden)

    1995-09-01

    The analysis of boron dilution accidents in pressurised water reactors has traditionally assumed that mixing is instantaneous and complete everywhere, eliminating in this way the possibility of concentration inhomogeneities. Situations can nevertheless arise where a volume of coolant with a low boron concentration may eventually enter the core and generate a severe reactivity transient. The work presented in this paper deals with a category of Rapid Boron Dilution Events characterised by a rapid start of a Reactor Coolant Pump (RCP) with a plug of relatively unborated water present in the RCS pipe. Model tests have been made at Vattenfall Utveckling AB in a simplified 1:5 scale model of a Westinghouse PWR. Conductivity measurements are used to determine dimensionless boron concentration. The main purpose of this experimental work is to define an experimental benchmark against which a mathematical model can be tested. The final goal is to be able to numerically predict Boron Dilution Transients. This work has been performed as a part of a Co-operative Agreement with Electricite` de France (EDF).

  3. The Dilution Effect and Information Integration in Perceptual Decision Making.

    Directory of Open Access Journals (Sweden)

    Jared M Hotaling

    Full Text Available In cognitive science there is a seeming paradox: On the one hand, studies of human judgment and decision making have repeatedly shown that people systematically violate optimal behavior when integrating information from multiple sources. On the other hand, optimal models, often Bayesian, have been successful at accounting for information integration in fields such as categorization, memory, and perception. This apparent conflict could be due, in part, to different materials and designs that lead to differences in the nature of processing. Stimuli that require controlled integration of information, such as the quantitative or linguistic information (commonly found in judgment studies, may lead to suboptimal performance. In contrast, perceptual stimuli may lend themselves to automatic processing, resulting in integration that is closer to optimal. We tested this hypothesis with an experiment in which participants categorized faces based on resemblance to a family patriarch. The amount of evidence contained in the top and bottom halves of each test face was independently manipulated. These data allow us to investigate a canonical example of sub-optimal information integration from the judgment and decision making literature, the dilution effect. Splitting the top and bottom halves of a face, a manipulation meant to encourage controlled integration of information, produced farther from optimal behavior and larger dilution effects. The Multi-component Information Accumulation model, a hybrid optimal/averaging model of information integration, successfully accounts for key accuracy, response time, and dilution effects.

  4. The Dilution Effect and Information Integration in Perceptual Decision Making.

    Science.gov (United States)

    Hotaling, Jared M; Cohen, Andrew L; Shiffrin, Richard M; Busemeyer, Jerome R

    2015-01-01

    In cognitive science there is a seeming paradox: On the one hand, studies of human judgment and decision making have repeatedly shown that people systematically violate optimal behavior when integrating information from multiple sources. On the other hand, optimal models, often Bayesian, have been successful at accounting for information integration in fields such as categorization, memory, and perception. This apparent conflict could be due, in part, to different materials and designs that lead to differences in the nature of processing. Stimuli that require controlled integration of information, such as the quantitative or linguistic information (commonly found in judgment studies), may lead to suboptimal performance. In contrast, perceptual stimuli may lend themselves to automatic processing, resulting in integration that is closer to optimal. We tested this hypothesis with an experiment in which participants categorized faces based on resemblance to a family patriarch. The amount of evidence contained in the top and bottom halves of each test face was independently manipulated. These data allow us to investigate a canonical example of sub-optimal information integration from the judgment and decision making literature, the dilution effect. Splitting the top and bottom halves of a face, a manipulation meant to encourage controlled integration of information, produced farther from optimal behavior and larger dilution effects. The Multi-component Information Accumulation model, a hybrid optimal/averaging model of information integration, successfully accounts for key accuracy, response time, and dilution effects.

  5. Dilution testing using rapid diagnostic tests in a HIV diagnostic algorithm: a novel alternative for confirmation testing in resource limited settings.

    Science.gov (United States)

    Shanks, Leslie; Siddiqui, M Ruby; Abebe, Almaz; Piriou, Erwan; Pearce, Neil; Ariti, Cono; Masiga, Johnson; Muluneh, Libsework; Wazome, Joseph; Ritmeijer, Koert; Klarkowski, Derryck

    2015-05-14

    Current WHO testing guidelines for resource limited settings diagnose HIV on the basis of screening tests without a confirmation test due to cost constraints. This leads to a potential risk of false positive HIV diagnosis. In this paper, we evaluate the dilution test, a novel method for confirmation testing, which is simple, rapid, and low cost. The principle of the dilution test is to alter the sensitivity of a rapid diagnostic test (RDT) by dilution of the sample, in order to screen out the cross reacting antibodies responsible for falsely positive RDT results. Participants were recruited from two testing centres in Ethiopia where a tiebreaker algorithm using 3 different RDTs in series is used to diagnose HIV. All samples positive on the initial screening RDT and every 10th negative sample underwent testing with the gold standard and dilution test. Dilution testing was performed using Determine™ rapid diagnostic test at 6 different dilutions. Results were compared to the gold standard of Western Blot; where Western Blot was indeterminate, PCR testing determined the final result. 2895 samples were recruited to the study. 247 were positive for a prevalence of 8.5 % (247/2895). A total of 495 samples underwent dilution testing. The RDT diagnostic algorithm misclassified 18 samples as positive. Dilution at the level of 1/160 was able to correctly identify all these 18 false positives, but at a cost of a single false negative result (sensitivity 99.6 %, 95 % CI 97.8-100; specificity 100 %, 95 % CI: 98.5-100). Concordance between the gold standard and the 1/160 dilution strength was 99.8 %. This study provides proof of concept for a new, low cost method of confirming HIV diagnosis in resource-limited settings. It has potential for use as a supplementary test in a confirmatory algorithm, whereby double positive RDT results undergo dilution testing, with positive results confirming HIV infection. Negative results require nucleic acid testing to rule out false

  6. Quantification of fentanyl in serum by isotope dilution analysis using capillary gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Sera, Shoji; Goromaru, Tsuyoshi [Fukuyama Univ., Hiroshima (Japan); Sameshima, Teruko; Kawasaki, Koichi; Oda, Toshiyuki

    1998-06-01

    The quantitative determination of fentanyl (FT) in serum was examined by isotope dilution analysis using a capillary gas chromatograph equipped with a surface ionization detector. The separation of FT and its deuterated analogue, FT-{sup 2}H{sub 19}, was achieved within 15 min a column temperature of 260degC by using a 25 m column. Measurement of the samples prepared by the addition of a known amount of FT in the range of 0.2 to 40 ng/ml with 20 ng/ml of FT-{sup 2}H{sub 19} to human control serum allowed observation of a linear relationship between the peak area ratio and the added amount ratio. The correlation coefficient obtained by regression analysis was 0.999. The advantage of the present isotope dilution method was demonstrated by comparison with other FT analogues which substituted a propionyl group with an acetyl group or a phenethyl group with a benzyl group as the internal standard. The present method was used to determine the serum level of FT in surgical patients after i.v. administration. No endogenous compounds and concomitant drugs interfered with the detection of FT or FT-{sup 2}H{sub 19}. This method was considered to be useful for the pharmacokinetic study of FT in patients. (author)

  7. Quantification of fentanyl in serum by isotope dilution analysis using capillary gas chromatography

    International Nuclear Information System (INIS)

    Sera, Shoji; Goromaru, Tsuyoshi; Sameshima, Teruko; Kawasaki, Koichi; Oda, Toshiyuki

    1998-01-01

    The quantitative determination of fentanyl (FT) in serum was examined by isotope dilution analysis using a capillary gas chromatograph equipped with a surface ionization detector. The separation of FT and its deuterated analogue, FT- 2 H 19 , was achieved within 15 min a column temperature of 260degC by using a 25 m column. Measurement of the samples prepared by the addition of a known amount of FT in the range of 0.2 to 40 ng/ml with 20 ng/ml of FT- 2 H 19 to human control serum allowed observation of a linear relationship between the peak area ratio and the added amount ratio. The correlation coefficient obtained by regression analysis was 0.999. The advantage of the present isotope dilution method was demonstrated by comparison with other FT analogues which substituted a propionyl group with an acetyl group or a phenethyl group with a benzyl group as the internal standard. The present method was used to determine the serum level of FT in surgical patients after i.v. administration. No endogenous compounds and concomitant drugs interfered with the detection of FT or FT- 2 H 19 . This method was considered to be useful for the pharmacokinetic study of FT in patients. (author)

  8. Dosage of plutonium by isotopic dilution in irradiated fuels; Dosage du plutonium par dilution isotopique dans les combustibles irradies

    Energy Technology Data Exchange (ETDEWEB)

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

    1964-07-01

    Plutonium determination in irradiated fuels has been carried out for several years by isotopic dilution by Sebaci and SSM in collaboration. SECACI has made available to the SSM the necessary space and equipment in its Fontenay laboratories. This work has shown the importance of the valency cycle which should make it possible to obtain a uniform isotopic distribution in sample tracer mixtures, and also a satisfactory U/Pu separation. Now it has been noticed that the presence of an excess of uranium considerably modifies the oxidation-reduction reaction kinetics of the plutonium. We have therefore been led to change certain parts of the operational technique so as to have an efficient cycle and to thereby improve the U/Pu separation; the stability of the thermionic emission of the plutonium, connected to the quantity of residual uranium, has at the same time been improved and we can now carry out more precise isotopic analyses. We have also tried to eliminate as far as possible the isotopic contaminations by:using a more rational operational method; the equipment used has been the object of a special study. The evaporations are carried out so as to prevent the formation of saturated vapours inside the glove box. The material which cannot be changed after each operation is carefully cleaned every time a new sample is treated. With this technique, a second calibration of the tracer T{sub 2} has been undertaken using a new standard solution. This solution has been prepared very carefully by weighing uranium and plutonium of known chemical purity, and we believe that it can be guaranteed to be a good reference solution. The value of the {sup 233}U/{sup 242}Pu ratio of the tracer has been obtained with a relative accuracy of 0,5 per cent. This modified method is now being applied to the analysis of rods irradiated in G-3. (author) [French] La determination du plutonium par dilution isotopique dans les combustibles irradies est pratiquee depuis plusieurs annees en

  9. SLDAssay: A software package and web tool for analyzing limiting dilution assays.

    Science.gov (United States)

    Trumble, Ilana M; Allmon, Andrew G; Archin, Nancie M; Rigdon, Joseph; Francis, Owen; Baldoni, Pedro L; Hudgens, Michael G

    2017-11-01

    Serial limiting dilution (SLD) assays are used in many areas of infectious disease related research. This paper presents SLDAssay, a free and publicly available R software package and web tool for analyzing data from SLD assays. SLDAssay computes the maximum likelihood estimate (MLE) for the concentration of target cells, with corresponding exact and asymptotic confidence intervals. Exact and asymptotic goodness of fit p-values, and a bias-corrected (BC) MLE are also provided. No other publicly available software currently implements the BC MLE or the exact methods. For validation of SLDAssay, results from Myers et al. (1994) are replicated. Simulations demonstrate the BC MLE is less biased than the MLE. Additionally, simulations demonstrate that exact methods tend to give better confidence interval coverage and goodness-of-fit tests with lower type I error than the asymptotic methods. Additional advantages of using exact methods are also discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Comparison of dilution factors for German wastewater treatment plant effluents in receiving streams to the fixed dilution factor from chemical risk assessment.

    Science.gov (United States)

    Link, Moritz; von der Ohe, Peter C; Voß, Katharina; Schäfer, Ralf B

    2017-11-15

    Incomplete removal during wastewater treatment leads to frequent detection of compounds such as pharmaceuticals and personal care products in municipal effluents. A fixed standard dilution factor of 10 for effluents entering receiving water bodies is used during the exposure assessment of several chemical risk assessments. However, the dilution potential of German receiving waters under low flow conditions is largely unknown and information is sparse for other European countries. We calculated dilution factors for two datasets differing in spatial extent and wastewater treatment plant (WWTP) size: a national dataset comprising 1225 large WWTPs in Central and Northern Germany and a federal dataset for 678 WWTPs of a single state in Southwest Germany. We found that the fixed factor approach overestimates the dilution potential of 60% and 40% of receiving waters in the national and the federal dataset, with median dilution factors of 5 and 14.5, respectively. Under mean flow conditions, 8% of calculated dilution factors were below 10, with a median dilution factor of 106. We also calculated regional dilution factors that accounted for effluent inputs from upstream WWTPs. For the national and the federal dataset, 70% and 60% of calculated regional dilution factors fell below 10 under mean low flow conditions, respectively. Decrease of regional dilution potential in small receiving streams was mainly driven by the next WWTP upstream with a 2.5 fold drop of median regional dilution factors. Our results show that using the standard dilution factor of 10 would result in the underestimation of environmental concentrations for authorised chemicals by a factor of 3-5 for about 10% of WWTPs, especially during low flow conditions. Consequently, measured environmental concentrations might exceed predicted environmental concentrations and ecological risks posed by effluents could be much higher, suggesting that a revision of current risk assessment practices may be required

  11. Transport of Tank 241-SY-101 Waste Slurry: Effects of Dilution and Temperature on Critical Pipeline Velocity

    International Nuclear Information System (INIS)

    KP Recknagle; Y Onishi

    1999-01-01

    This report presents the methods and results of calculations performed to predict the critical velocity and pressure drop required for the two-inch pipeline transfer of solid/liquid waste slurry from underground waste storage Tank 241-SY-101 to Tank 241-SY- 102 at the Hanford Site. The effects of temperature and dilution on the critical velocity were included in the analysis. These analyses show that Tank 241-SY-101 slurry should be diluted with water prior to delivery to Tank 241-SY-102. A dilution ratio of 1:1 is desirable and would allow the waste to be delivered at a critical velocity of 1.5 ft/sec. The system will be operated at a flow velocity of 6 ft/sec or greater therefore, this velocity will be sufficient to maintain a stable slurry delivery through the pipeline. The effect of temperature on the critical velocity is not a limiting factor when the slurry is diluted 1:1 with water. Pressure drop at the critical velocity would be approximately two feet for a 125-ft pipeline (or 250-ft equivalent straight pipeline). At 6 ft/sec, the pressure drop would be 20 feet over a 250-ft equivalent straight pipeline

  12. Dilute-and-shoot coupled to nanoflow liquid chromatography high resolution mass spectrometry for the determination of drugs of abuse and sport drugs in human urine.

    Science.gov (United States)

    Alcántara-Durán, Jaime; Moreno-González, David; Beneito-Cambra, Miriam; García-Reyes, Juan F

    2018-05-15

    In this work, a sensitive nanoflow liquid chromatography high-resolution mass spectrometry screening method has been developed for the determination of multiclass drugs of abuse and sport drugs in human urine. 81 drugs belonging to different multiclass pharmaceuticals were targeted. The method is based on the use of a nanoLC column (75 µm × 150 mm, 3 µm particle size and 100 Å pore) with the nanospray emitter tip integrated so that dead volumes are significantly minimized. Data acquisition method included both full-scan and all ion fragmentation experiments using an Orbitrap analyser (Q-Exactive) operated in the positive ionization mode. To increase laboratory throughput, a dilute-and-shoot methodology has been tested and proposed, based solely on direct urine dilution without further sample workup. Matrix effects were evaluated, showing a negligible effect for all studied compounds when a dilution 1:50 was implemented. Despite this high-dilution factor, limits of quantification were still satisfactory, with values below 5 µg L -1 in most cases, being lower than their minimum required performance limits correspond established by the World Anti-Doping Agency. Therefore, the use of the dilute-and-shoot method with the enhanced sensitivity provided by nanoflow LC setup could be useful tool for the determination of studied compounds in drug testing, thus increasing laboratory performance, because a minimum sample treatment steps are required. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. Utilization of tritiated water dilution technique in determination of nitrogen partitioning in cashmere goats

    International Nuclear Information System (INIS)

    Wang Linfeng; Yang Gaiqing; Liu Ping; Zhang Shijun

    2010-01-01

    In order to investigate nitrogen partitioning in local cashmere goats, six Inner Mogolia White Cashmere goats between 2 to 2.5 years old were used to determine the nitrogen partitioning in cashmere goats. The total retained nitrogen (TN) in body, distribution of body nitrgen and hair nitrogen were measured by general digestive and metabolism method combined with tritiated water dilution technique. Results showed that the combined methods were ideal for determining body nitrgen (BN) and hair nitrogen (fur nitrogen, FN) of Cashmere goats. There were obvious significance between BN and FN in different seasons. In telogen, BN and FN partitioning was 75.7% ± 0.62% and 24.3% ± 0.62%, respectively. Whereas, it changed to 66.6% ± 2.2% and 33.4% ± 2.2% in anagen. BN partitioning decreased when the season changed from telogen to anagen, while FN partitioning increased, which indicated that more nitrogen substance was partitioned to body growth in telogen, and more nitrogen substance was distribute to cashmere growth in anagen. These transformation were related to the changing of photoperiod and some hormones, such as melatonin (MT), prolactin (PRL) and IGF-I. It could be concluded that tritiated water dilution technique can be used to detect body protein content as well as BN, combining general digestive and metabolism experiment, FN partitoning can be determined. BN and FN partitoning varied with the season in cashmere goats because of hormones changing. (authors)

  14. A Study of the Vacancy-Impurity Interaction in Dilute Nickel Alloys by Core Electron Annihilation

    Science.gov (United States)

    Arbuzov, V. L.; Danilov, S. E.; Druzhkov, A. P.

    1997-08-01

    It is shown that the angular correlation of annihilation radiation can be used to identify vacancy-impurity complexes in dilute alloys. Annihilation of trapped positrons with core electrons bears information about the chemical environment of a vacancy defect. The method is especially effective for d-matrices doped with sp-impurities since annihilation parameters of positrons with d- and sp-shell electrons differ considerably. The potentialities of the method of core-electron annihilation of positrons are demonstrated taking electron-irradiated dilute Ni-P and Ni-Si alloys as an example. It is shown that the interaction between the vacancies, which migrate at the III stage of annealing, and P atoms in Ni-P causes a considerable change in the annihilation parameters of positrons with core electrons compared to pure Ni. In Ni-Si alloys the annihilation parameters of trapped positrons with core electrons do not differ from those in Ni. This fact is an evidence that Si atoms do not interact with vacancies in Ni.

  15. Determination of zinc stable isotopes in biological materials using isotope dilution inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Patterson, K.Y.; Veillon, Claude

    1992-01-01

    A method is described for using isotope dilution to determine both the amount of natural zinc and enriched isotopes of zinc in biological samples. Isotope dilution inductively coupled plasma mass spectrometry offers a way to quantify not only the natural zinc found in a sample but also the enriched isotope tracers of zinc. Accurate values for the enriched isotopes and natural zinc are obtained by adjusting the mass count rate data for measurable instrumental biases. Analytical interferences from the matrix are avoided by extracting the zinc from the sample matrix using diethylammonium diethyldithiocarbamate. The extraction technique separates the zinc from elements which form interfering molecular ions at the same nominal masses as the zinc isotopes. Accuracy of the method is verified using standard reference materials. The detection limit is 0.06 μg Zn per sample. Precision of the abundance ratios range from 0.3-0.8%. R.S.D. for natural zinc concentrations is about 200-600 μg g -1 . The accuracy and precision of the measurements make it possible to follow enriched isotopic tracers of zinc in biological samples in metabolic tracer studies. (author). 19 refs.; 1 fig., 4 tabs

  16. DMSP and DMS dynamics and microzooplankton grazing in the Labrador Sea: application of the dilution technique

    Science.gov (United States)

    Wolfe, Gordon V.; Levasseur, Maurice; Cantin, Guy; Michaud, Sonia

    2000-12-01

    We adapted the dilution technique to study microzooplankton grazing of algal dimethylsulfoniopropionate (DMSP) vs. Chl a, and to estimate the impact of microzooplankton grazing on dimethyl sulfide (DMS) production in the Labrador Sea. Phytoplankton numbers were dominated by autotrophic nanoflagellates in the Labrador basin, but diatoms and colonial Phaeocystis pouchetii contributed significantly to phytomass at several high chlorophyll stations and on the Newfoundland and Greenland shelfs. Throughout the region, growth of algal Chl a and DMSP was generally high (0.2-1 d -1), but grazing rates were lower and more variable, characteristic of the early spring bloom period. Production and consumption of Chl a vs. DMSP followed no clear pattern, and sometimes diverged greatly, likely because of their differing distributions among algal prey taxa and size class. In several experiments where Phaeocystis was abundant, we observed DMS production proportional to grazing rate, and we found clear evidence of DMS production by this haptophyte following physical stress such as sparging or filtration. It is possible that grazing-activated DMSP cleavage by Phaeocystis contributes to grazer deterrence: protozoa and copepods apparently avoided healthy colonies (as judged by relative growth and grazing rates of Chl a and DMSP), and grazing of Phaeocystis was significant only at one station where cells were in poor condition. Although we hoped to examine selective grazing on or against DMSP-containing algal prey, the dilution technique cannot differentiate selective ingestion and varying digestion rates of Chl a and DMSP. We also found that the dilution method alone was poorly suited for assessing the impact of grazing on dissolved sulfur pools, because of rapid microbial consumption and the artifactual release of DMSP and DMS during filtration. Measuring and understanding the many processes affecting organosulfur cycling by the microbial food web in natural populations remain a

  17. Microstructure Related Characterization of a-Si:H Thin Films PECVD Deposited under Varied Hydrogen Dilution

    Directory of Open Access Journals (Sweden)

    Veronika Vavrunkova

    2007-01-01

    Full Text Available We report on the structure and optical properties of hydrogenated silicon thin films deposited by plasma - enhanced chemical vapor deposition (PECVD from silane diluted with hydrogen in a wide dilution range. The samples deposited with dilutions below 30 were detected as amorphous hydrogenated silicon (a-Si:H with crystalline grains of several nanometers in size which represent the medium-range order of a-Si:H. The optical characterization confirmed increasing ordering with the increasing dilution. The optical band gap was observed to be increasing function of the dilution.

  18. Direct quantification of creatinine in human urine by using isotope dilution extractive electrospray ionization tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Li Xue [Institute of Environmental Pollution and Health, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444 (China); Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation, Applied Chemistry Department, East China Institute of Technology, Nanchang 330013 (China); Fang Xiaowei [Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation, Applied Chemistry Department, East China Institute of Technology, Nanchang 330013 (China); Yu Zhiqiang; Sheng Guoying [Guangdong Key Laboratory of Environmental Protection and Resource Utilization, State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Wu Minghong [Shanghai Applied Radiation Institute, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444 (China); Fu Jiamo [Institute of Environmental Pollution and Health, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444 (China); Guangdong Key Laboratory of Environmental Protection and Resource Utilization, State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Chen Huanwen, E-mail: chw8868@gmail.com [Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation, Applied Chemistry Department, East China Institute of Technology, Nanchang 330013 (China)

    2012-10-20

    Highlights: Black-Right-Pointing-Pointer High throughput analysis of urinary creatinine is achieved by using ID-EESI-MS/MS. Black-Right-Pointing-Pointer Urine sample is directly analyzed and no sample pre-treatment is required. Black-Right-Pointing-Pointer Accurate quantification is accomplished with isotope dilution technique. - Abstract: Urinary creatinine (CRE) is an important biomarker of renal function. Fast and accurate quantification of CRE in human urine is required by clinical research. By using isotope dilution extractive electrospray ionization tandem mass spectrometry (EESI-MS/MS) a high throughput method for direct and accurate quantification of urinary CRE was developed in this study. Under optimized conditions, the method detection limit was lower than 50 {mu}g L{sup -1}. Over the concentration range investigated (0.05-10 mg L{sup -1}), the calibration curve was obtained with satisfactory linearity (R{sup 2} = 0.9861), and the relative standard deviation (RSD) values for CRE and isotope-labeled CRE (CRE-d3) were 7.1-11.8% (n = 6) and 4.1-11.3% (n = 6), respectively. The isotope dilution EESI-MS/MS method was validated by analyzing six human urine samples, and the results were comparable with the conventional spectrophotometric method (based on the Jaffe reaction). Recoveries for individual urine samples were 85-111% and less than 0.3 min was taken for each measurement, indicating that the present isotope dilution EESI-MS/MS method is a promising strategy for the fast and accurate quantification of urinary CRE in clinical laboratories.

  19. Direct quantification of creatinine in human urine by using isotope dilution extractive electrospray ionization tandem mass spectrometry

    International Nuclear Information System (INIS)

    Li Xue; Fang Xiaowei; Yu Zhiqiang; Sheng Guoying; Wu Minghong; Fu Jiamo; Chen Huanwen

    2012-01-01

    Highlights: ► High throughput analysis of urinary creatinine is achieved by using ID-EESI–MS/MS. ► Urine sample is directly analyzed and no sample pre-treatment is required. ► Accurate quantification is accomplished with isotope dilution technique. - Abstract: Urinary creatinine (CRE) is an important biomarker of renal function. Fast and accurate quantification of CRE in human urine is required by clinical research. By using isotope dilution extractive electrospray ionization tandem mass spectrometry (EESI–MS/MS) a high throughput method for direct and accurate quantification of urinary CRE was developed in this study. Under optimized conditions, the method detection limit was lower than 50 μg L −1 . Over the concentration range investigated (0.05–10 mg L −1 ), the calibration curve was obtained with satisfactory linearity (R 2 = 0.9861), and the relative standard deviation (RSD) values for CRE and isotope-labeled CRE (CRE-d3) were 7.1–11.8% (n = 6) and 4.1–11.3% (n = 6), respectively. The isotope dilution EESI–MS/MS method was validated by analyzing six human urine samples, and the results were comparable with the conventional spectrophotometric method (based on the Jaffe reaction). Recoveries for individual urine samples were 85–111% and less than 0.3 min was taken for each measurement, indicating that the present isotope dilution EESI–MS/MS method is a promising strategy for the fast and accurate quantification of urinary CRE in clinical laboratories.

  20. Study of Enzymatic Hydrolysis of Dilute Acid Pretreated Coconut Husk

    Directory of Open Access Journals (Sweden)

    Rudy Agustriyanto

    2012-12-01

    Full Text Available Coconut husk is classified as complex lignocellulosic material that contains cellulose, hemicellulose, lignin, and some other extractive compounds. Cellulose from coconut husk can be used as fermentation substrate after enzymatic hydrolysis. In contrary, lignin content from the coconut husk will act as an inhibitor in this hydrolysis process. Therefore, a pretreatment process is needed to enhance the hydrolysis of cellulose. The objective of this research is to investigate the production of the glucose through dilute acid pretreatment and to obtain its optimum operating conditions. In this study, the pretreatment was done using dilute sulfuric acid in an autoclave reactor. The pretreatment condition were varied at 80°C, 100°C, 120°C and 0.9%, 1.2%, 1.5% for temperature and acid concentration respectively. The acid pretreated coconut husk was then hydrolyzed using commercial cellulase (celluclast and β-glucosidase (Novozyme 188. The hydrolysis time was 72 hours and the operating conditions were varied at several temperature and pH. From the experimental results it can be concluded that the delignification temperature variation has greater influence than the acid concentration. The optimum operating condition was obtained at pH 4 and 50°C which was pretreated at 100°C using 1.5% acid concentration. Copyright © 2012 by BCREC UNDIP. All rights reserved. (Selected Paper from International Conference on Chemical and Material Engineering (ICCME 2012Received: 28th September 2012, Revised: 2nd October 2012, Accepted: 4th October 2012[How to Cite: R. Agustriyanto, A. Fatmawati, Y. Liasari. (2012. Study of Enzymatic Hydrolysis of Dilute Acid Pretreated Coconut Husk. Bulletin of Chemical Reaction Engineering & Catalysis, 7(2: 137-141. doi:10.9767/bcrec.7.2.4046.137-141] [How to Link / DOI: http://dx.doi.org/10.9767/bcrec.7.2.4046.137-141 ] | View in 

  1. Experimentally evaluating the origin of dilute magnetism in nanomaterials

    International Nuclear Information System (INIS)

    Pereira, L M C

    2017-01-01

    Reports of room-temperature ferromagnetism continue to emerge for an ever-growing range of nanomaterials with a small or even vanishing concentration of magnetic atoms. Dilute magnetic semiconductors (DMS) are the most representative class of such materials, but similar magnetic properties have been reported in many others. Challenging our understanding of magnetic order in solids, as well as our ability to experimentally assess it, these remarkable magnetic phenomena have become one of the most controversial topics in magnetism. Various non-intrinsic sources of ferromagnetism (e.g. instrumental artifacts and magnetic contamination) are becoming well documented, and rarely are all of them taken into account when room-temperature ferromagnetism is reported. This topical review is intended to serve as a guide when evaluating to what extent a given data set supports the claim of intrinsic ferromagnetism in dilute nanomaterials. It compiles the most relevant sources of non-intrinsic ferromagnetism which have been reported, as well as guidelines for how to minimize them. It also provides an overview of complementary structural and magnetic characterization techniques which can be combined to provide different levels of scrutiny of the intrinsic nature of experimentally observed ferromagnetism. In particular, it gives some notable examples of how comprehensive studies based on those techniques have led to a remarkably detailed understanding of model DMS materials, with strong evidence of absence of room-temperature ferromagnetism. Although mostly based on DMS research, this review provides a set of guidelines and cautionary notes of broader relevance, including some emerging new fields of dilute nanomagnetism such as magnetically doped 3D topological insulators, 3D Dirac semimetals, and 2D materials. (topical review)

  2. Dilution-Induced Formation of Hybrid Perovskite Nanoplatelets.

    Science.gov (United States)

    Tong, Yu; Ehrat, Florian; Vanderlinden, Willem; Cardenas-Daw, Carlos; Stolarczyk, Jacek K; Polavarapu, Lakshminarayana; Urban, Alexander S

    2016-12-27

    Perovskite nanocrystals (NCs) are an important extension to the fascinating field of hybrid halide perovskites. Showing significantly enhanced photoluminescence (PL) efficiency and emission wavelengths tunable through halide content and size, they hold great promise for light-emitting applications. Despite the rapid advancement in this field, the physical nature and size-dependent excitonic properties have not been well investigated due to the challenges associated with their preparation. Herein we report the spontaneous formation of highly luminescent, quasi-2D organic-inorganic hybrid perovskite nanoplatelets (NPls) upon dilution of a dispersion of bulk-like NCs. The fragmentation of the large NCs is attributed to osmotic swelling induced by the added solvent. An excess of organic ligands in the solvent quickly passivates the newly formed surfaces, stabilizing the NPls in the process. The thickness of the NPls can be controlled both by the dilution level and by the ligand concentration. Such colloidal NPls and their thin films were found to be extremely stable under continuous UV light irradiation. Full tunability of the NPl emission wavelength is achieved by varying the halide ion used (bromide, iodide). Additionally, time-resolved PL measurements reveal an increasing radiative decay rate with decreasing thickness of the NPls, likely due to an increasing exciton binding energy. Similarly, measurements on iodide-containing NPls show a transformation from biexponential to monoexponential PL decay with decreasing thickness, likely due to an increasing fraction of excitonic recombination. This interesting phenomenon of change in fluorescence upon dilution is a result of the intricate nature of the perovskite material itself and is uncommon in inorganic materials. Our findings enable the synthesis of halide perovskite NCs with high quantum efficiency and good stability as well as a tuning of both their optical and morphological properties.

  3. Experimentally evaluating the origin of dilute magnetism in nanomaterials

    Science.gov (United States)

    Pereira, L. M. C.

    2017-10-01

    Reports of room-temperature ferromagnetism continue to emerge for an ever-growing range of nanomaterials with a small or even vanishing concentration of magnetic atoms. Dilute magnetic semiconductors (DMS) are the most representative class of such materials, but similar magnetic properties have been reported in many others. Challenging our understanding of magnetic order in solids, as well as our ability to experimentally assess it, these remarkable magnetic phenomena have become one of the most controversial topics in magnetism. Various non-intrinsic sources of ferromagnetism (e.g. instrumental artifacts and magnetic contamination) are becoming well documented, and rarely are all of them taken into account when room-temperature ferromagnetism is reported. This topical review is intended to serve as a guide when evaluating to what extent a given data set supports the claim of intrinsic ferromagnetism in dilute nanomaterials. It compiles the most relevant sources of non-intrinsic ferromagnetism which have been reported, as well as guidelines for how to minimize them. It also provides an overview of complementary structural and magnetic characterization techniques which can be combined to provide different levels of scrutiny of the intrinsic nature of experimentally observed ferromagnetism. In particular, it gives some notable examples of how comprehensive studies based on those techniques have led to a remarkably detailed understanding of model DMS materials, with strong evidence of absence of room-temperature ferromagnetism. Although mostly based on DMS research, this review provides a set of guidelines and cautionary notes of broader relevance, including some emerging new fields of dilute nanomagnetism such as magnetically doped 3D topological insulators, 3D Dirac semimetals, and 2D materials.

  4. Analyses of PWR boron dilution consequences with the Arrotta code

    International Nuclear Information System (INIS)

    Johanson, E.; Cheng, H.W.; Sehgal, B.R.

    1998-03-01

    During the past few years, major attention has been paid to analyzing the issue of reactivity initiated accidents (RIAs), of which the boron dilution event is of very special interest to the countries having pressurized water reactors (PWRs) in their nuclear power delivery systems. The scenario considered is that if an inadvertent accumulation of boron free water in one loop during reactor startup operations of a PWR and the inadvertent startup of the reactor coolant pump (RCP) in the loop. This could then lead to a rapid boron dilution in the core, which can in turn give rise to a power excursion. This report is devoted to studying the potential physical and thermal hydraulic consequences of a slug of diluted coolant entering the core after one RCP start under a couple of postulated cases. The severity of the consequences of such a scenario is primarily determined by the amount of positive reactivity insertion, and they are also related to the reactivity insertion rate. Therefore, in the report, detailed calculations and analyses have been carried out from case to case by using the well-known space-time kinetics code, ARROTTA. As a result, the spatial distribution for nodal power, fuel enthalpy, fuel temperature and clad outside temperature as well as the change in core reactivity, total core power and peak fuel temperature can be provided. In general, the maximum fuel enthalpy, peak fuel temperature, and clad outside temperature, for all the cases considered in the report, do not exceed their respective routine safety limitations because of the strong Doppler effect and moderator temperature feedback, except if the safety limitations on fuel enthalpy addition for high burnup fuel are drastically reduced

  5. Activity coefficients at infinite dilution for hydrocarbons in furfuryl alcohol at T=(278.15 and 298.15) K, determined by g.l.c

    International Nuclear Information System (INIS)

    Kozlowska, Marta K.; Letcher, Trevor M.; Domanska, Urszula

    2004-01-01

    The potential of the polar solvent, furfuryl alcohol, as a solvent in the separation of aromatics from aliphatics and other hydrocarbons, has been investigated by measuring activity coefficients at infinite dilution. The activity coefficients at infinite dilution for some alkanes, cycloalkanes, alkenes, alkynes and benzene in furfuryl alcohol have been determined by g.l.c. at T=(278.15 and 298.15) K. The method used is we believe, a more controlled and reliable method than the alternative pre-saturation method. The results have been used to calculate the selectivity factor and hence predict the potential for furfuryl alcohol as a solvent in separating aromatic compounds from aliphatic compounds and other hydrocarbons using extractive distillation. The results have been compared to the recently published work on a related polar solvent - furfural. The excess enthalpies of mixing at infinite dilution have also been calculated

  6. Assessment of theoretical and experimental results in the calculation of atmospheric dilution factors in the Atucha I nuclear power plant

    International Nuclear Information System (INIS)

    Quintana, E.E.; Tossi, M.H.; Telleria, D.M.

    1990-01-01

    Collective doses produced during the normal working of the Atucha I Nuclear Power Plant are calculated using annual atmospheric factors. This work studies the behaviour of the dilution factors in different periods of the year in order to fit the calculated dose model applying factors from seasonal, monthly or weekly periods. The Radiation Protection Group of the C.N.E.A. have carried out continuous environmental monitoring in the surroundings of the Atucha I Nuclear Power Plant. These studies include the measurement of air tritium concentration, radionuclide that is found principally as tritiated water vapour. This isotope, normally released by the nuclear power plant was used as a tracer to assess the atmospheric dilution factors. Factors were calculated by two methods: an experimental one, based on environmental measurements of the tritium concentration in the surroundings of the nuclear power plant and another one by applying a theoretical model based on information from the micrometeorological tower located in the mentioned place. To carry out the environmental monitoring, four monitoring stations in the surroundings of the power plant were chosen. Three of them are approximately one kilometer from the plant and the fourth is 7.5 km away, near the city of Lima. To condense and collect the atmospheric water vapour, an overcooling system was used. The measurement was performed by liquid scintillation counting, previous alkaline electrolytical enrichment of the samples. The theoretical model uses hourly values of direction and wind intensity, as well as the atmospheric dispersive properties. Values obtained during the period 1976 to 1988 allowed, applying statistical tests, to validate the theoretical model and to observe seasonal variation of the dilution factors throughout the same year and between different years. Finally, results and graphics are presented showing that the behaviour of the dilution factors in different periods of the year. It is recommended to

  7. The Influence of Seed-borne N in 15N Isotope Dilution Studies with Legumes The Influence of Seed-borne N in 15N Isotope Dilution Studies with Legumes

    DEFF Research Database (Denmark)

    Jensen, Erik Steen; Andersen, A. J.; Thomsen, J. D.

    1985-01-01

    The distriution of seed-borne N in shoot and root of pea and field bean was studied using three methods: 1) determination of the N content in shoot and root of plants grown in sand culture without other N sources. 2) 15N isotope dilution in plants grown in Rhizobium-free medium supplied with 15N-...... of corrections for seed-borne N in studies of nitrogen fixation in legumes is discussed....

  8. Recovery of Platinum from Dilute Chloride Media Using Biosorbents

    Science.gov (United States)

    Zeytuncu, B.; Morcali, M. H.; Yucel, O.

    Pistachio nut shells and Rice husk, a biomass residue, were investigated as adsorbents for the platinum uptake from synthetically prepared dilute chloroplatinic acid solutions. The effects of the different uptake parameters on platinum uptake (%) were studied in detail on a batch sorption. Before the pistachio nut shell material was activated, platinum uptake (%) was poor compared with rice husk. However, after the pistachio nut shell material was activated at 1000°C under an argon atmosphere, the platinum uptake (%) increased two-fold. The pistachio nut shell (inactivated and activated) and rice husk were characterized by Attenuated Total Reflection-Fourier transform infrared spectroscopy (ATR-FTIR).

  9. Practical design of a heat exchanger for dilution refrigeration. 1

    Energy Technology Data Exchange (ETDEWEB)

    Oda, Y; Fujii, G; Nagano, H [Tokyo Univ. (Japan). Inst. for Solid State Physics

    1978-02-01

    A compact heat exchanger for a dilution refrigerator with a high thermal efficiency is presented. Discrete heat exchangers with by-pass channels were used to decrease the flow impedance. This heat exchanger was designed so that the thermal conductance of liquid along the stream was greatly reduced. The effective thickness of the sponge material in the heat exchanger and mixer is also discussed. The obtained minimum temperatures of 12 mK was very close to the designed value of 10.8 mK. Moreover a rapid response was obtained. This is attributed to the small liquid volume of the heat exchanger.

  10. Redox substoichiometry in isotope dilution analysis Pt. 4

    International Nuclear Information System (INIS)

    Kambara, T.; Yoshioka, H.; Ugai, Y.

    1980-01-01

    The oxidation reaction of antimony(III) with potassium dichromate has been investigated radiometrically. The quantitative oxidation of antimony(III) was found to be not disturbed even in large amounts of tin(IV). On the basis of these results the redox substoichiometric isotope dilution analysis using potassium dichromate as the oxidizing agent was proposed for the determination of antimony in metallic tin. An antimony content of 1.22+-0.05 μg in metallic tin (10 mg) was determined without separation of the matrix element. (author)

  11. Effect of fractons and magnons in dilute ferromagnets on resistivity

    International Nuclear Information System (INIS)

    Li Jianxin; Jiang Qing; Tian Decheng

    1993-01-01

    Based on the s - d exchange model, we investigate the temperature-dependent resistivity arising from the scattering of electrons off fractons and magnons in dilute Heisenberg ferromagnets on three-dimensional bond percolation network. The results indicate that the contribution of fracton scatterings to the resistivity varies from T 3 / 2 to T 2 dependence as the concentration of bonds approaches the percolation threshold, while the magnon scattering contributes a resistivity varying as T 3 / 2 regardless of the changes in concentration of bonds. (author). 21 refs, 4 figs

  12. Optical absorption of dilute solutions of metals in molten salts

    Energy Technology Data Exchange (ETDEWEB)

    Senatore, G.; Parrinello, M.; Tosi, M.P. (Trieste Univ. (Italy). Ist. di Fisica Teorica; Gruppo Nazionale di Struttura dell material del CNR, Trieste (Italy); International Centre for Theoretical Physics, Trieste (Italy))

    1978-12-23

    The theory of liquid structure for fluids of charged hard spheres is applied to an evaluation of the F-centre model for valence electrons in metal-molten salt solutions at high dilution. Minimization of the free energy yields the groundstate radius of the elctron bubble and hence the optical excitation energy in a Franck-Condon transition, the shift and broadening of the transition due to fluctuations in the bubble radius, the volume of mixing, and the activity of the salt in the solution.

  13. Cooperative fluorescence from a strongly driven dilute cloud of atoms

    DEFF Research Database (Denmark)

    Ott, Johan Raunkjær; Wubs, Martijn; Lodahl, Peter

    2013-01-01

    We investigate cooperative fluorescence in a dilute cloud of strongly driven two-level emitters. Starting from the Heisenberg equations of motion, we compute the first-order scattering corrections to the saturation of the excited-state population and to the resonance-fluorescence spectrum, which...... both require going beyond the state-of-the-art linear-optics approach to describe collective phenomena. A dipole blockade is observed due to long-range dipole-dipole coupling that vanishes at stronger driving fields. Furthermore, we compute the inelastic component of the light scattered by a cloud...

  14. Dispersion of Sound in Dilute Suspensions with Nonlinear Particle Relaxation

    Science.gov (United States)

    Kandula, Max

    2010-01-01

    The theory accounting for nonlinear particle relaxation (viscous and thermal) has been applied to the prediction of dispersion of sound in dilute suspensions. The results suggest that significant deviations exist for sound dispersion between the linear and nonlinear theories at large values of Omega(Tau)(sub d), where Omega is the circular frequency, and Tau(sub d) is the Stokesian particle relaxation time. It is revealed that the nonlinear effect on the dispersion coefficient due to viscous contribution is larger relative to that of thermal conduction

  15. Condensate statistics in interacting and ideal dilute bose gases

    Science.gov (United States)

    Kocharovsky; Kocharovsky; Scully

    2000-03-13

    We obtain analytical formulas for the statistics, in particular, for the characteristic function and all cumulants, of the Bose-Einstein condensate in dilute weakly interacting and ideal equilibrium gases in the canonical ensemble via the particle-number-conserving operator formalism of Girardeau and Arnowitt. We prove that the ground-state occupation statistics is not Gaussian even in the thermodynamic limit. We calculate the effect of Bogoliubov coupling on suppression of ground-state occupation fluctuations and show that they are governed by a pair-correlation, squeezing mechanism.

  16. Tailoring spin-orbit torque in diluted magnetic semiconductors

    KAUST Repository

    Li, Hang; Wang, Xuhui; Doǧan, Fatih; Manchon, Aurelien

    2013-01-01

    We study the spin orbit torque arising from an intrinsic linear Dresselhaus spin-orbit coupling in a single layer III-V diluted magnetic semiconductor. We investigate the transport properties and spin torque using the linear response theory, and we report here: (1) a strong correlation exists between the angular dependence of the torque and the anisotropy of the Fermi surface; (2) the spin orbit torque depends nonlinearly on the exchange coupling. Our findings suggest the possibility to tailor the spin orbit torque magnitude and angular dependence by structural design.

  17. Thermodynamics of dilute gases: application to submonolayer He films

    International Nuclear Information System (INIS)

    Vetrovec, M.B.; Carneiro, G.M.

    1979-01-01

    The thermodynamic properties of submonolayer He films are calculated. Expressions are first obtained for the thermodynamic properties of dilute systems of particles interacting through a short range potential taking into account binary interactions between the particles. These expressions are exact in the limit n→0, n being the particle number density, and are valid at all temperatures. At high temperatures these expressions are reduced to those obtained using the virial expansion truncated after the second term. These expressions are next applied to He in two dimensions and the results compared with experiment and with previous calculations [pt

  18. Radiolysis of dilute aqueous solutions of cesium iodide

    International Nuclear Information System (INIS)

    Gorbovitskaya, T.I.; Galinkin, D.L.; Kants, L.K.; Tiliks, Yu.E.; Kotelkin, I.M.; Luzanova, L.M.

    1993-01-01

    Study of physical-chemical processes in the NPP containment by severe accident is carried out. Radiolysis of reactor cooling water containing iodine and cesium radionuclides penetrated therein in the course of accident is considered as of such processes. Role of ionizing radiation in the process of formation and release of ecologically hazardous volatile forms of radioiodine from reactor water into environment is studied. Experiments on radiolysis of CsI diluted water solutions are carried out. The data obtained were used for clarification of radiolysis mechanism for iodine-containing water system, enabling forecast of iodine behaviour in the course of the accident. 5 refs., 4 figs., 1 tab

  19. Dilute bismides for near and mid-infrared applications

    DEFF Research Database (Denmark)

    Song, Yuxin; Gu, Yi; Ye, Hong

    2013-01-01

    Dilute bismides are a group of emerging materials with unique properties. Incorporation of a small amount of Bi in common III–V host materials results in large band-gap reduction and strong spin-orbit splitting, leading to potential applications in near-infrared (NIR) and mid-infrared (MIR......) optoelectronics. Recent progresses on molecular beam epitaxy (MBE) of novel III-Sb-Bi, i.e. GaSbBi and InSbBi thin films from our group are summarised in this paper. Quantum well structures based on GaSbBi and InGaAsBi aiming for the optical communication window were grown and characterized....

  20. Acetone and acetaldehyde determination in tomato juice by isotopic dilution

    International Nuclear Information System (INIS)

    Piva, M.-T.; Crouzet, J.

    1977-01-01

    Acetone and acetaldehyde content of tomato juice were determined by isotope dilution techniques. The juice is added to 14 C labelled compounds, carried along by nitrogen at low pressure. The mixture of 2.4 dinitrophenylhydrazones obtained from volatile compounds is separated by thin layer chromatography on silica gel and then on alumina. A determination of radioactivity and concentration of acetone and acetaldehyde 2,4 dinitrophenylhydrazones obtained after separation and elution allow to calculate the content of these two compounds in the initial product with the same sample. This technique could be used for determination of methanol and ethanol after transformation in 3,5 dinitrobenzoates [fr

  1. Hydrogenated dilute nitride semiconductors theory, properties, and applications

    CERN Document Server

    Ciatto, Gianluca

    2015-01-01

    ""The electrical and optical properties of the technologically and scientifically important dilute nitride semiconductors are strongly influenced by the introduction of atomic hydrogen. This volume is an excellent summary and resource for the most recent understanding of experimental results and state-of-the-art theoretical studies of the formation, reversibility, and microscopic structure of nitrogen-hydrogen complexes in these materials. The book details how a wide variety of experimental techniques have provided a detailed understanding of the role of hydrogen. It is the premier sourc

  2. Tailoring spin-orbit torque in diluted magnetic semiconductors

    KAUST Repository

    Li, Hang

    2013-05-16

    We study the spin orbit torque arising from an intrinsic linear Dresselhaus spin-orbit coupling in a single layer III-V diluted magnetic semiconductor. We investigate the transport properties and spin torque using the linear response theory, and we report here: (1) a strong correlation exists between the angular dependence of the torque and the anisotropy of the Fermi surface; (2) the spin orbit torque depends nonlinearly on the exchange coupling. Our findings suggest the possibility to tailor the spin orbit torque magnitude and angular dependence by structural design.

  3. Scanning Hall probe microscopy of a diluted magnetic semiconductor

    International Nuclear Information System (INIS)

    Kweon, Seongsoo; Samarth, Nitin; Lozanne, Alex de

    2009-01-01

    We have measured the micromagnetic properties of a diluted magnetic semiconductor as a function of temperature and applied field with a scanning Hall probe microscope built in our laboratory. The design philosophy for this microscope and some details are described. The samples analyzed in this work are Ga 0.94 Mn 0.06 As films grown by molecular beam epitaxy. We find that the magnetic domains are 2-4 μm wide and fairly stable with temperature. Magnetic clusters are observed above T C , which we ascribe to MnAs defects too small and sparse to be detected by a superconducting quantum interference device magnetometer.

  4. Scanning Hall probe microscopy of a diluted magnetic semiconductor

    Science.gov (United States)

    Kweon, Seongsoo; Samarth, Nitin; de Lozanne, Alex

    2009-05-01

    We have measured the micromagnetic properties of a diluted magnetic semiconductor as a function of temperature and applied field with a scanning Hall probe microscope built in our laboratory. The design philosophy for this microscope and some details are described. The samples analyzed in this work are Ga0.94Mn0.06As films grown by molecular beam epitaxy. We find that the magnetic domains are 2-4 μm wide and fairly stable with temperature. Magnetic clusters are observed above TC, which we ascribe to MnAs defects too small and sparse to be detected by a superconducting quantum interference device magnetometer.

  5. Yfiler® Plus population samples and dilution series

    DEFF Research Database (Denmark)

    Andersen, Mikkel Meyer; Mogensen, Helle Smidt; Eriksen, Poul Svante

    2017-01-01

    DNA complicated the analysis by causing drop-ins of characteristic female DNA artefacts. Even though the customised analytical threshold in combination with the custom-made artefact filters gave more alleles, crime scene samples still needed special attention from the forensic geneticist....... dynamics and performance. We determined dye-dependent analytical thresholds by receiver operating characteristics (ROC) and made a customised artefact filter that includes theoretical known artefacts by use of previously analysed population samples. Dilution series of known male DNA and a selection...

  6. Domain walls in (Ga,Mn)As diluted magnetic semiconductor

    Czech Academy of Sciences Publication Activity Database

    Sugawara, A.; Kasai, H.; Tonomura, A.; Brown, P.D.; Campion, R. P.; Edmonds, K. W.; Gallagher, B. L.; Zemen, Jan; Jungwirth, Tomáš

    2008-01-01

    Roč. 100, č. 4 (2008), 047202/1-047202/4 ISSN 0031-9007 R&D Projects: GA MŠk LC510; GA ČR GEFON/06/E002; GA ČR GA202/05/0575; GA ČR GA202/04/1519 EU Projects: European Commission(XE) 015728 - NANOSPIN Institutional research plan: CEZ:AV0Z10100521 Keywords : dilute ferromagnetic semiconductor * Néel domain walls * electron holography * Landau-Lifshitz-Gilbert simulation Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 7.180, year: 2008

  7. Application of the mass spectrometry-isotope dilution technique for the determination of uranium contents in rocks

    International Nuclear Information System (INIS)

    Kakazu, M.H.; Iyer, S.S.

    1980-01-01

    Application of the spectrometric isotope dilution technique for the accurate determination of parts per million range of uranium in rock samples is described. The various aspects of the method like sample dissolution, ion exchange separation, mass spectrometric procedures are discussed. A single filament ionization source was employed for the isotope analysis. A carbon reduction method was used to reduce uranium oxide ions to uranium metal ions. The tracer solution for isotope dilution was prepared from National Bureau of Standards uranium isotopic Standard NBS U-970. Uranium contents are meassured for nine rock samples and the values obtained are compared with the uranium values measured by others workers. Errors caused in the uranium determination due to sample splitting problems as well as the incomplete acid digestion of the samples are discussed. (Author) [pt

  8. Quantitative Analysis of Ingenol in Euphorbia species via Validated Isotope Dilution Ultra-high Performance Liquid Chromatography Tandem Mass Spectrometry

    Czech Academy of Sciences Publication Activity Database

    Béres, T.; Dragull, K.; Pospíšil, Jiří; Tarkowská, Danuše; Dančák, M.; Bíba, Ondřej; Tarkowski, P.; Doležal, K.; Strnad, Miroslav

    2018-01-01

    Roč. 29, č. 1 (2018), s. 23-29 ISSN 0958-0344 R&D Projects: GA ČR GA17-14007S; GA MŠk(CZ) LO1204 Institutional support: RVO:61389030 Keywords : Euphorbia genus * ingenol * isotope-dilution method * mass spectrometry * ultra-high performance liquid chromatography Subject RIV: FD - Oncology ; Hematology OBOR OECD: Analytical chemistry Impact factor: 2.292, year: 2016

  9. Entanglement and Zeeman interaction in diluted magnetic semiconductor quantum dot

    International Nuclear Information System (INIS)

    Hichri, A.; Jaziri, S.

    2004-01-01

    We present theoretically the Zeeman coupling and exchange-induced swap action in spin-based quantum dot quantum computer models in the presence of magnetic field. We study the valence and conduction band states in a double quantum dots made in diluted magnetic semiconductor. The latter have been proven to be very useful in building an all-semiconductor platform for spintronics. Due to a strong p-d exchange interaction in diluted magnetic semiconductor (Cd 0.57 Mn 0.43 Te), the relative contribution of this component is strongly affected by an external magnetic field, a feature that is absent in nonmagnetic double quantum dots. We determine the energy spectrum as a function of magnetic field within the Hund-Mulliken molecular-orbit approach and by including the Coulomb interaction. Since we show that the ground state of the two carriers confined in a vertically coupled quantum dots provide a possible realization for a gate of a quantum computer, the crossing between the lowest states, caused by the giant spin splitting, can be observed as a pronounced jump in the magnetization of small magnetic field amplitude. Finally, we determine the swap time as a function of magnetic field and the inter dot distance. We estimate quantitatively swap errors caused by the field, establishing that error correction would, in principle, be possible in the presence of nonuniform magnetic field in realistic structures

  10. Large-deviation theory for diluted Wishart random matrices

    Science.gov (United States)

    Castillo, Isaac Pérez; Metz, Fernando L.

    2018-03-01

    Wishart random matrices with a sparse or diluted structure are ubiquitous in the processing of large datasets, with applications in physics, biology, and economy. In this work, we develop a theory for the eigenvalue fluctuations of diluted Wishart random matrices based on the replica approach of disordered systems. We derive an analytical expression for the cumulant generating function of the number of eigenvalues IN(x ) smaller than x ∈R+ , from which all cumulants of IN(x ) and the rate function Ψx(k ) controlling its large-deviation probability Prob[IN(x ) =k N ] ≍e-N Ψx(k ) follow. Explicit results for the mean value and the variance of IN(x ) , its rate function, and its third cumulant are discussed and thoroughly compared to numerical diagonalization, showing very good agreement. The present work establishes the theoretical framework put forward in a recent letter [Phys. Rev. Lett. 117, 104101 (2016), 10.1103/PhysRevLett.117.104101] as an exact and compelling approach to deal with eigenvalue fluctuations of sparse random matrices.

  11. Novel understanding of calcium silicate hydrate from dilute hydration

    KAUST Repository

    Zhang, Lina

    2017-05-13

    The perspective of calcium silicate hydrate (C-S-H) is still confronting various debates due to its intrinsic complicated structure and properties after decades of studies. In this study, hydration at dilute suspension of w/s equaling to 10 was conducted for tricalcium silicate (C3S) to interpret long-term hydration process and investigate the formation, structure and properties of C-S-H. Based on results from XRD, IR, SEM, NMR and so forth, loose and dense clusters of C-S-H with analogous C/S ratio were obtained along with the corresponding chemical formulae proposed as Ca5Si4O13∙6.2H2O. Crystalline structure inside C-S-H was observed by TEM, which was allocated at the foil-like proportion as well as the edge of wrinkles of the product. The long-term hydration process of C3S in dilute suspension could be sketchily described as migration of calcium hydroxide and in-situ growth of C-S-H with equilibrium silicon in aqueous solution relatively constant and calcium varied.

  12. Crystallization of calcium oxalate in minimally diluted urine

    Science.gov (United States)

    Bretherton, T.; Rodgers, A.

    1998-09-01

    Crystallization of calcium oxalate was studied in minimally diluted (92%) urine using a mixed suspension mixed product crystallizer in series with a Malvern particle sizer. The crystallization was initiated by constant flow of aqueous sodium oxalate and urine into the reaction vessel via two independent feed lines. Because the Malvern cell was in series with the reaction vessel, noninvasive measurement of particle sizes could be effected. In addition, aliquots of the mixed suspension were withdrawn and transferred to a Coulter counter for crystal counting and sizing. Steady-state particle size distributions were used to determine nucleation and growth kinetics while scanning electron microscopy was used to examine deposited crystals. Two sets of experiments were performed. In the first, the effect of the concentration of the exogenous sodium oxalate was investigated while in the second, the effect of temperature was studied. Calcium oxalate nucleation and growth rates were found to be dependent on supersaturation levels inside the crystallizer. However, while growth rate increased with increasing temperature, nucleation rates decreased. The favored phases were the trihydrate at 18°C, the dihydrate at 38° and the monohydrate at 58°C. The results of both experiments are in agreement with those obtained in other studies that have been conducted in synthetic and in maximally diluted urine and which have employed invasive crystal counting and sizing techniques. As such, the present study lends confidence to the models of urinary calcium oxalate crystallization processes which currently prevail in the literature.

  13. Host polymer influence on dilute polystyrene segmental dynamics

    Science.gov (United States)

    Lutz, T. R.

    2005-03-01

    We have utilized deuterium NMR to investigate the segmental dynamics of dilute (2%) d3-polystyrene (PS) chains in miscible polymer blends with polybutadiene, poly(vinyl ethylene), polyisoprene, poly(vinyl methylether) and poly(methyl methacrylate). In the dilute limit, we find qualitative differences depending upon whether the host polymer has dynamics that are faster or slower than that of pure PS. In blends where PS is the fast (low Tg) component, segmental dynamics are slowed upon blending and can be fit by the Lodge-McLeish model. When PS is the slow (high Tg) component, PS segmental dynamics speed up upon blending, but cannot be fit by the Lodge-McLeish model unless a temperature dependent self-concentration is employed. These results are qualitatively consistent with a recent suggestion by Kant, Kumar and Colby (Macromolecules, 2003, 10087), based upon data at higher concentrations. Furthermore, as the slow component, we find the segmental dynamics of PS has a temperature dependence similar to that of its host. This suggests viewing the high Tg component dynamics in a miscible blend as similar to a polymer in a low molecular weight solvent.

  14. Hydrogen isotope exchange of organic compounds in dilute acid at elevated temperatures

    International Nuclear Information System (INIS)

    Werstiuk, N.H.

    1987-01-01

    Introduction of one or more deuterium (or tritium) atoms into organic molecules can be accomplished in many ways depending on the nature of the substrate and the extent and sterochemistry of deuteriation or tritiation required. Some of the common methods include acid- and base-catalyzed exchange of carbonyl compounds, metal hydride reductions, dissolving metal reductions, catalytic reduction of double bonds, chromatographic exchange, homogeneous and heterogeneous metal-catalyzed exchange, base-catalyzed exchange of carbon acids other than carbonyl compounds and acid-catalyzed exchange via electrophilic substitution. Only the latter three methods have been used for perdeuteriation of organic compounds. A very useful compendium of labeling methods with examples has been available to chemists for some time. Although metal-catalyzed exchange has been used extensively, the method suffers from some deficiencies: irreproducibility of catalyst surfaces, catalyst poisoning, side reactions such as coupling and hydrogenolysis of labile groups and low deuterium incorporation. Usually a number of cycles are required with fresh catalyst and fresh deuterium source to achieve substantial isotope incorporation. Acid-catalyzed exchange of aromatics and alkenes, strongly acidic media such as liquid DBr, concentrated DBr, acetic acid/stannic chloride, concentrated D 3 PO 4 , concentrated DC1, D 3 PO 4 /BF 3 SO 2 , 50-80% D 2 SO 4 and DFSO 4 /SbF 5 at moderate temperatures (<100 degrees) have been used to effect exchange. The methods are not particularly suitable for large scale deuteriations because of the cost and the fact that the recovery and upgrading of the diluted deuterium pool is difficult. This paper describes the hydrogen isotope exchange of a variety of organic compounds in dilute aqueous acid (0.1-0.5 M) at elevated temperatures (150-300 degrees)

  15. Determination of serum calcium levels by 42Ca isotope dilution inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Han, Bingqing; Ge, Menglei; Zhao, Haijian; Yan, Ying; Zeng, Jie; Zhang, Tianjiao; Zhou, Weiyan; Zhang, Jiangtao; Wang, Jing; Zhang, Chuanbao

    2017-11-27

    Serum calcium level is an important clinical index that reflects pathophysiological states. However, detection accuracy in laboratory tests is not ideal; as such, a high accuracy method is needed. We developed a reference method for measuring serum calcium levels by isotope dilution inductively coupled plasma mass spectrometry (ID ICP-MS), using 42Ca as the enriched isotope. Serum was digested with 69% ultrapure nitric acid and diluted to a suitable concentration. The 44Ca/42Ca ratio was detected in H2 mode; spike concentration was calibrated by reverse IDMS using standard reference material (SRM) 3109a, and sample concentration was measured by a bracketing procedure. We compared the performance of ID ICP-MS with those of three other reference methods in China using the same serum and aqueous samples. The relative expanded uncertainty of the sample concentration was 0.414% (k=2). The range of repeatability (within-run imprecision), intermediate imprecision (between-run imprecision), and intra-laboratory imprecision were 0.12%-0.19%, 0.07%-0.09%, and 0.16%-0.17%, respectively, for two of the serum samples. SRM909bI, SRM909bII, SRM909c, and GBW09152 were found to be within the certified value interval, with mean relative bias values of 0.29%, -0.02%, 0.10%, and -0.19%, respectively. The range of recovery was 99.87%-100.37%. Results obtained by ID ICP-MS showed a better accuracy than and were highly correlated with those of other reference methods. ID ICP-MS is a simple and accurate candidate reference method for serum calcium measurement and can be used to establish and improve serum calcium reference system in China.

  16. Comparison of agar dilution and antibiotic gradient strip test with broth microdilution for susceptibility testing of swine Brachyspira species.

    Science.gov (United States)

    Mirajkar, Nandita S; Gebhart, Connie J

    2016-03-01

    Production-limiting diseases in swine caused by Brachyspira are characterized by mucohemorrhagic diarrhea (B. hyodysenteriae and "B. hampsonii") or mild colitis (B. pilosicoli), while B. murdochii is often isolated from healthy pigs. Emergence of novel pathogenic Brachyspira species and strains with reduced susceptibility to commonly used antimicrobials has reinforced the need for standardized susceptibility testing. Two methods are currently used for Brachyspira susceptibility testing: agar dilution (AD) and broth microdilution (BMD). However, these tests have primarily been used for B. hyodysenteriae and rarely for B. pilosicoli. Information on the use of commercial susceptibility testing products such as antibiotic gradient strips is lacking. Our main objective was to validate and compare the susceptibility results, measured as the minimum inhibitory concentration (MIC), of 6 antimicrobials for 4 Brachyspira species (B. hyodysenteriae, "B. hampsonii", B. pilosicoli, and B. murdochii) by BMD and AD (tiamulin, valnemulin, lincomycin, tylosin, and carbadox) or antibiotic gradient strip (doxycycline) methods. In general, the results of a high percentage of all 4 Brachyspira species differed by ±1 log2 dilution or less by BMD and AD for tiamulin, valnemulin, lincomycin, and tylosin, and by BMD and antibiotic gradient strip for doxycycline. The carbadox MICs obtained by BMD were 1-5 doubling dilutions different than those obtained by AD. BMD for Brachyspira was quicker to perform with less ambiguous interpretation of results when compared with AD and antibiotic gradient strip methods, and the results confirm the utility of BMD in routine diagnostics. © 2016 The Author(s).

  17. Isotope dilution alpha spectrometry for the determination of plutonium concentration in irradiated fuel dissolver solution : IDAS and R-IDAS

    International Nuclear Information System (INIS)

    Ramaniah, M.V.; Jain, H.C.; Aggarwal, S.K.; Chitambar, S.A.; Kavimandan, V.D.; Almaula, A.I.; Shah, P.M.; Parab, A.R.; Sant, V.L.

    1980-01-01

    The report presents a new technique, Isotope Dilution Alpha Spectrometry (IDAS) and Reverse Isotope Dilution Alpha Spectrometry (R-IDAS) for determining the concentration of plutonium in the irradiated fuel dissolver solution. The method exploits sup(238)Pu in IDAS and sup(239)Pu in R-IDAS as a spike and provides an alternative method to Isotope Dilution Mass Spectrometry (IDMS) which requires enriched sup(242)Pu as a spike. Depending upon the burn-up of the fuel, sup(238)Pu or sup(239)Pu is used as a spike to change the sup(238)Pu/(sup(239)Pu+sup(240)Pu)α activity ratio in the sample by a factor of 10. This change is determined by α-spectrometry on electrodeposited sources using a solid state silicon surface barrier detector coupled to a multichannel analyser. The validity of a simple method based on the geometric progression (G.P.) decrease for the far tail of the spectrum to correct for the tail contribution of sup(238)Pu peak (5.50 MeV) to the low energy sup(239)Pu + sup(240)Pu peak (5.17 MeV) is established. Results for the plutonium concentration on different irradiated fuel dissolver solutions with burn-uo ranging from J,000 to 100,000 MWD/TU are presented and compared with those obtained by IDMS. The values obtained by IDAS or R-IDAS and IDMS agree within 0.5%. (auth.)

  18. Impact of recycling stillage on conversion of dilute sulfuric acid pretreated corn stover to ethanol.

    Science.gov (United States)

    Mohagheghi, Ali; Schell, Daniel J

    2010-04-01

    Both the current corn starch to ethanol industry and the emerging lignocellulosic biofuels industry view recycling of spent fermentation broth or stillage as a method to reduce fresh water use. The objective of this study was to understand the impact of recycling stillage on conversion of corn stover to ethanol. Sugars in a dilute-acid pretreated corn stover hydrolysate were fermented to ethanol by the glucose-xylose fermenting bacteria Zymomonas mobilis 8b. Three serial fermentations were performed at two different initial sugar concentrations using either 10% or 25% of the stillage as makeup water for the next fermentation in the series. Serial fermentations were performed to achieve near steady state concentration of inhibitors and other compounds in the corn stover hydrolysate. Little impact on ethanol yields was seen at sugar concentrations equivalent to pretreated corn stover slurry at 15% (w/w) with 10% recycle of the stillage. However, ethanol yields became progressively poorer as the sugar concentration increased and fraction of the stillage recycled increased. At an equivalent corn stover slurry concentration of 20% with 25% recycled stillage the ethanol yield was only 5%. For this microorganism with dilute-acid pretreated corn stover, recycling a large fraction of the stillage had a significant negative impact on fermentation performance. Although this finding is of concern for biochemical-based lignocellulose conversion processes, other microorganism/pretreatment technology combinations will likely perform differently. (c) 2009 Wiley Periodicals, Inc.

  19. On-Surface Pseudo-High-Dilution Synthesis of Macrocycles: Principle and Mechanism.

    Science.gov (United States)

    Fan, Qitang; Wang, Tao; Dai, Jingya; Kuttner, Julian; Hilt, Gerhard; Gottfried, J Michael; Zhu, Junfa

    2017-05-23

    Macrocycles have attracted much attention due to their specific "endless" topology, which results in extraordinary properties compared to related linear (open-chain) molecules. However, challenges still remain in their controlled synthesis with well-defined constitution and geometry. Here, we report the successful application of the (pseudo-)high-dilution method to the conditions of on-surface synthesis in ultrahigh vacuum. This approach leads to high yields (up to 84%) of cyclic hyperbenzene ([18]-honeycombene) via an Ullmann-type reaction from 4,4″-dibromo-meta-terphenyl (DMTP) as precursor on a Ag(111) surface. The mechanism of macrocycle formation was explored in detail using scanning tunneling microscopy and X-ray photoemission spectroscopy. We propose that the dominant pathway for hyperbenzene (MTP) 6 formation is the stepwise desilverization of an organometallic (MTP-Ag) 6 macrocycle, which forms via cyclization of (MTP-Ag) 6 chains under pseudo-high-dilution conditions. The high probability of cyclization on the stage of the organometallic phase results from the reversibility of the C-Ag bond. The case is different from that in solution, in which cyclization typically occurs on the stage of a covalently bonded open-chain precursor. This difference in the cyclization mechanism on a surface compared to that in solution stems mainly from the 2D confinement exerted by the surface template, which hinders the flipping of chain segments necessary for cyclization.

  20. Quantitative analysis of 39 polybrominated diphenyl ethers by isotope dilution GC/low-resolution MS.

    Science.gov (United States)

    Ackerman, Luke K; Wilson, Glenn R; Simonich, Staci L

    2005-04-01

    A GC/low-resolution MS method for the quantitative isotope dilution analysis of 39 mono- to heptabrominated diphenyl ethers was developed. The effects of two different ionization sources, electron impact (EI) and electron capture negative ionization (ECNI), and the effects of their parameters on production of high-mass fragment ions [M - xH - yBr](-) specific to PBDEs were investigated. Electron energy, emission current, source temperature, ECNI system pressure, and choice of ECNI reagent gases were optimized. Previously unidentified enhancement of PBDE high-mass fragment ion [M - xH - yBr](-) abundance was achieved. Electron energy had the largest impact on PBDE high-mass fragment ion abundance for both the ECNI and EI sources. By monitoring high-mass fragment ions of PBDEs under optimized ECNI source conditions, quantitative isotope dilution analysis of 39 PBDEs was conducted using nine (13)C(12) labeled PBDEs on a low-resolution MS with low picogram to femtogram instrument detection limits.

  1. Estimation of Optimum Dilution in the GMAW Process Using Integrated ANN-GA

    Directory of Open Access Journals (Sweden)

    P. Sreeraj

    2013-01-01

    Full Text Available To improve the corrosion resistant properties of carbon steel, usually cladding process is used. It is a process of depositing a thick layer of corrosion resistant material over carbon steel plate. Most of the engineering applications require high strength and corrosion resistant materials for long-term reliability and performance. By cladding these properties can be achieved with minimum cost. The main problem faced on cladding is the selection of optimum combinations of process parameters for achieving quality clad and hence good clad bead geometry. This paper highlights an experimental study to optimize various input process parameters (welding current, welding speed, gun angle, and contact tip to work distance and pinch to get optimum dilution in stainless steel cladding of low carbon structural steel plates using gas metal arc welding (GMAW. Experiments were conducted based on central composite rotatable design with full replication technique, and mathematical models were developed using multiple regression method. The developed models have been checked for adequacy and significance. In this study, artificial neural network (ANN and genetic algorithm (GA techniques were integrated and labeled as integrated ANN-GA to estimate optimal process parameters in GMAW to get optimum dilution.

  2. Isotope Dilution - Thermal Ionisation Mass Spectrometric Analysis for Tin in a Fly Ash Material

    International Nuclear Information System (INIS)

    Hernandez, C.; Fernandez, M.; Quejido, A. L.

    2006-01-01

    Isotope dilution-thermal ionisation mass spectrometry (ID-TIMS) analysis has been applied to the determination of tin in a fly ash sample supplied by the EC Joint Research Centre (Ispra, Italy). The proposed procedure includes the silica gel/phosphoric acid technique for tin thermal ionisation activation and a strict heating protocol for isotope ratio measurements. Instrumental mass discrimination factor has been previously determined measuring a natural tin standard solution. Spike solutions has been prepared from 112Sn-enriched metal and quantified by reverse isotope dilution analysis. Two sample aliquots were spiked and tin was extracted with 4,5 M HCI during 25 min ultrasound esposure time. Due to the complex matrix of this fly ash material, a two-steps purification stage using ion-exchange chromatography was required prior TIMS analysis. Obtained results for the two sample-spike blends (10,10 + - 0,55 y 10,50 + - 0,64 imolg-1) are comprarable, both value and uncertainty. Also a good reproducibility is observed between measurements. The proposed ID-TIMS procedure, as a primary method and due to the lack of fly ash reference material certified for tin content, can be used to validate more routine methodologies applied to tin determination in this kind of materials. (Author) 75 refs

  3. Diffusion coefficients of alloying elements in dilute Mg alloys: A comprehensive first-principles study

    International Nuclear Information System (INIS)

    Zhou, Bi-Cheng; Shang, Shun-Li; Wang, Yi; Liu, Zi-Kui

    2016-01-01

    First-principles calculations based on density functional theory have been used to calculate the temperature-dependent dilute tracer diffusion coefficients for 47 substitutional alloying elements in hexagonal closed packed (hcp) Mg by combining transition state theory and an 8-frequency model. The minimum energy pathways and the saddle point configurations during solute migration are calculated with the climbing image nudged elastic band method. Vibrational properties are obtained using the quasi-harmonic Debye model with inputs from first-principles calculations. An improved generalized gradient approximation of PBEsol is used in the present first-principles calculations, which is able to well describe both vacancy formation energies and vibrational properties. It is found that the solute diffusion coefficients in hcp Mg are roughly inversely proportional to the bulk modulus of the dilute alloys, which reflects the solutes' bonding to Mg. Transition metal elements with d electrons show strong interactions with Mg and have large diffusion activation energies. Correlation effects are not negligible for solutes Ca, Na, Sr, Se, Te, and Y, in which the direct solute migration barriers are much smaller than the solvent (Mg) migration barriers. Calculated diffusion coefficients are in remarkable agreement with available experimental data in the literature.

  4. Dilute Sulfuric Acid Pretreatment of Agricultural and Agro-Industrial Residues for Ethanol Production

    Science.gov (United States)

    Martin, Carlos; Alriksson, Björn; Sjöde, Anders; Nilvebrant, Nils-Olof; Jönsson, Leif J.

    The potential of dilute-acid prehydrolysis as a pretreatment method for sugarcane bagasse, rice hulls, peanut shells, and cassava stalks was investigated. The prehydrolysis was performed at 122°C during 20, 40, or 60 min using 2% H2SO4 at a solid-to-liquid ratio of 1∶10. Sugar formation increased with increasing reaction time. Xylose, glucose, arabinose, and galactose were detected in all of the prehydrolysates, whereas mannose was found only in the prehydrolysates of peanut shells and cassava stalks. The hemicelluloses of bagasse were hydrolyzed to a high-extent yielding concentrations of xylose and arabinose of 19.1 and 2.2 g/L, respectively, and a xylan conversion of more than 80%. High-glucose concentrations (26-33.5 g/L) were found in the prehydrolysates of rice hulls, probably because of hydrolysis of starch of grain remains in the hulls. Peanut shells and cassava stalks rendered low amounts of sugars on prehydrolysis, indicating that the conditions were not severe enough to hydrolyze the hemicelluloses in these materials quantitatively. All prehydrolysates were readily fermentable by Saccharomyces cerevisiae. The dilute-acid prehydrolysis resulted in a 2.7-to 3.7-fold increase of the enzymatic convertibility of bagasse, but was not efficient for improving the enzymatic hydrolysis of peanut shells, cassava stalks, or rice hulls.

  5. Effectiveness of intra-arterial anesthesia for uterine fibroid embolization using dilute lidocaine

    International Nuclear Information System (INIS)

    Zhan, Songhua; Li, Yi; Wang, Guoliang; Han, Hongjie; Yang, Zhenyan

    2005-01-01

    A modified protocol of uterine fibroid embolization (UFE) is proposed for alleviating the postinterventional pain. This randomized and double-blinded clinical trial is to evaluate the effectiveness of intra-arterial infusion of dilute lidocaine for postinterventional pain relief in UFE. Forty-six patients who underwent UFE were randomly grouped equally. In the test group, after the poly(vinyl alcohol) embolization was complete, a dilute lidocaine solution with 40 mg in 6.0 ml, 3.0 ml for each side or 4.0 and 2.0 ml for two sides, was given through the catheter. In the control group, the patients received 6.0 ml of saline solution as a placebo. A simple pain degree classification method for patient self-evaluation was developed. A questionnaire was completed by each patient to record the degree of pain during five periods; these were during the procedure, the first 12 h, the second 12 h, between 24 and 48 h, and between 48 and 72 h. The numbers of patients with the same degree of pain in the five time segments from the two groups were statistically compared. Compared with the control group, the patients in the test group experienced less pain within 48 h after the procedure (p<0.01). The results suggest that this improved UFE protocol is a simple approach to prevent the acute postinterventional pain of UFE. (orig.)

  6. Two fixed ratio dilutions for soil salinity monitoring in hypersaline wetlands.

    Directory of Open Access Journals (Sweden)

    Juan Herrero

    Full Text Available Highly soluble salts are undesirable in agriculture because they reduce yields or the quality of most cash crops and can leak to surface or sub-surface waters. In some cases salinity can be associated with unique history, rarity, or special habitats protected by environmental laws. Yet in considering the measurement of soil salinity for long-term monitoring purposes, adequate methods are required. Both saturated paste extracts, intended for agriculture, and direct surface and/or porewater salinity measurement, used in inundated wetlands, are unsuited for hypersaline wetlands that often are only occasionally inundated. For these cases, we propose the use of 1:5 soil/water (weight/weight extracts as the standard for expressing the electrical conductivity (EC of such soils and for further salt determinations. We also propose checking for ion-pairing with a 1:10 or more diluted extract in hypersaline soils. As an illustration, we apply the two-dilutions approach to a set of 359 soil samples from saline wetlands ranging in ECe from 2.3 dS m(-1 to 183.0 dS m(-1. This easy procedure will be useful in survey campaigns and in the monitoring of soil salt content.

  7. Two fixed ratio dilutions for soil salinity monitoring in hypersaline wetlands.

    Science.gov (United States)

    Herrero, Juan; Weindorf, David C; Castañeda, Carmen

    2015-01-01

    Highly soluble salts are undesirable in agriculture because they reduce yields or the quality of most cash crops and can leak to surface or sub-surface waters. In some cases salinity can be associated with unique history, rarity, or special habitats protected by environmental laws. Yet in considering the measurement of soil salinity for long-term monitoring purposes, adequate methods are required. Both saturated paste extracts, intended for agriculture, and direct surface and/or porewater salinity measurement, used in inundated wetlands, are unsuited for hypersaline wetlands that often are only occasionally inundated. For these cases, we propose the use of 1:5 soil/water (weight/weight) extracts as the standard for expressing the electrical conductivity (EC) of such soils and for further salt determinations. We also propose checking for ion-pairing with a 1:10 or more diluted extract in hypersaline soils. As an illustration, we apply the two-dilutions approach to a set of 359 soil samples from saline wetlands ranging in ECe from 2.3 dS m(-1) to 183.0 dS m(-1). This easy procedure will be useful in survey campaigns and in the monitoring of soil salt content.

  8. Determination of trace quantities of uranium in rocks mass spectrometric isotope dilution technique

    International Nuclear Information System (INIS)

    Kakazu, Mauricio Hiromitu

    1980-01-01

    A detailed experimental investigation on the thermionic emission of uranium deposited on a single flat type rhenium filament has been carried out. The study was aimed at determining the influence of various forms of deposition on the emission sensitivity and thermal stability of U + , UO + and UO 2 + ions. Based on these investigations, a technique, involving an addition of a small quantity of colloidal suspension of graphite on top of the uranyl nitrate sample deposited, was chosen because of its higher, emission sensitivity for uranium metal ions. The experimental parameters of the technique were optimised and the technique was employed in the determination of trace quantities of uranium in rock samples using mass spectrometric isotope dilution method. For the mass spectrometric isotope dilution analysis National Bureau of Standards uranium isotopic standard NBS-U 970 was employed as a tracer, where as the mass discrimination effect in the uranium isotope analysis was corrected using the uranium isotopic standard NBS-U500. Uranium was determined in each of the seven granite samples from Wyoming, USA and two USGS standard rocks. The precision of the analysis was found to be ±1% . The uranium values obtained on the rock samples were compared with the analyses of other investigators. Influence of the sample splitting on the uranium analysis was discussed in the light of the analytical results obtained.(author)

  9. Effectiveness of intra-arterial anesthesia for uterine fibroid embolization using dilute lidocaine

    Energy Technology Data Exchange (ETDEWEB)

    Zhan, Songhua; Li, Yi; Wang, Guoliang; Han, Hongjie; Yang, Zhenyan [Tongji Hospital of Tongji University, Department of Radiology, Shanghai (China)

    2005-08-01

    A modified protocol of uterine fibroid embolization (UFE) is proposed for alleviating the postinterventional pain. This randomized and double-blinded clinical trial is to evaluate the effectiveness of intra-arterial infusion of dilute lidocaine for postinterventional pain relief in UFE. Forty-six patients who underwent UFE were randomly grouped equally. In the test group, after the poly(vinyl alcohol) embolization was complete, a dilute lidocaine solution with 40 mg in 6.0 ml, 3.0 ml for each side or 4.0 and 2.0 ml for two sides, was given through the catheter. In the control group, the patients received 6.0 ml of saline solution as a placebo. A simple pain degree classification method for patient self-evaluation was developed. A questionnaire was completed by each patient to record the degree of pain during five periods; these were during the procedure, the first 12 h, the second 12 h, between 24 and 48 h, and between 48 and 72 h. The numbers of patients with the same degree of pain in the five time segments from the two groups were statistically compared. Compared with the control group, the patients in the test group experienced less pain within 48 h after the procedure (p<0.01). The results suggest that this improved UFE protocol is a simple approach to prevent the acute postinterventional pain of UFE. (orig.)

  10. Improvement of sample preparation for input plutonium accountability measurement by isotope dilution gammy-ray spectroscopy

    International Nuclear Information System (INIS)

    Nishida, K.; Kuno, Y.; Sato, S.; Masui, J.; Li, T.K.; Parker, J.L.; Hakkila, E.A.

    1992-01-01

    The sample preparation method for the isotope dilution gamma-ray spectrometry (IDGS) technique has been further improved for simultaneously determining the plutonium concentration and isotopic composition of highly irradiated spent-fuel dissolver solutions. The improvement includes using ion-exchange filter papers (instead of resin beads, as in two previous experiments) for better separation and recovery of plutonium from fission products. The results of IDGS measurements for five dissolver solutions are in good agreement with those by mass spectrometry with ∼0.4% for plutonium concentration and ∼0.1% for 239 Pu isotopic composition. The precision of the plutonium concentration is ∼1% with a 1-h count time. The technique could be implemented as an alternative method for input accountability and verification measurements in reprocessing plants

  11. In vivo synthesized 34S enriched amino acid standards for species specific isotope dilution of proteins

    DEFF Research Database (Denmark)

    Hermann, Gerrit; Moller, Laura Hyrup; Gammelgaard, Bente

    2016-01-01

    (ICP-MS) combined to anion exchange showed that very high concentrated spike material could be produced with [small mu ]mol amounts of proteinogenic sulfur containing amino acids per g cell dry weight. An enrichment of 34S to 96.3 +/- 0.4% (n = 3) and 98.5 +/- 0.4% (n = 3) for cysteic acid...... with the concept of species specific isotope dilution analysis (IDA). The method relies on the determination of the two sulfur containing amino acids, cysteine and methionine by sulfur speciation analysis and is hence applicable to any protein containing sulfur. In vivo synthesis using 34S as sulfur source...... and methionine sulfone, respectively, was assessed. The established IDA method was validated for the absolute quantification of commercially available lysozyme and ceruloplasmin standards including the calculation of a total combined uncertainty budget....

  12. The interlaboratory experiment IDA-72 on mass spectrometric isotope dilution analysis. Vol. 2

    International Nuclear Information System (INIS)

    Beyrich, W.; Drosselmeyer, E.

    1975-07-01

    Volume II of the report on the IDA-72 experiment contains papers written by different authors on a number of special topics connected with the preparation, performance and evaluation of the interlaboratory test. In detail the sampling procedures for active samples of the reprocessing plant and the preparation of inactive reference and spike solution from standard material are described as well as new methods of sample conditioning by evaporation. An extra chapter is devoted to the chemical sample treatment as a preparation for mass spectrometric analysis of the U and Pu content of the solutions. Special topics are also methods for mass discrimination corrections, α-spectrometer measurements as a supplement for the determination of Pu-238 and the comparison of concentration determinations by mass spectrometric isotope dilution analysis with those performed by X-ray fluorescence spectrometry. The last part of this volume contains papers connected with the computerized statistical evaluation of the high number of data. (orig.) [de

  13. 1H NMR quantification in very dilute toxin solutions: application to anatoxin-a analysis.

    Science.gov (United States)

    Dagnino, Denise; Schripsema, Jan

    2005-08-01

    A complete procedure is described for the extraction, detection and quantification of anatoxin-a in biological samples. Anatoxin-a is extracted from biomass by a routine acid base extraction. The extract is analysed by GC-MS, without the need of derivatization, with a detection limit of 0.5 ng. A method was developed for the accurate quantification of anatoxin-a in the standard solution to be used for the calibration of the GC analysis. 1H NMR allowed the accurate quantification of microgram quantities of anatoxin-a. The accurate quantification of compounds in standard solutions is rarely discussed, but for compounds like anatoxin-a (toxins with prices in the range of a million dollar a gram), of which generally only milligram quantities or less are available, this factor in the quantitative analysis is certainly not trivial. The method that was developed can easily be adapted for the accurate quantification of other toxins in very dilute solutions.

  14. Computation of infinite dilute activity coefficients of binary liquid alloys using complex formation model

    Energy Technology Data Exchange (ETDEWEB)

    Awe, O.E., E-mail: draweoe2004@yahoo.com; Oshakuade, O.M.

    2016-04-15

    A new method for calculating Infinite Dilute Activity Coefficients (γ{sup ∞}s) of binary liquid alloys has been developed. This method is basically computing γ{sup ∞}s from experimental thermodynamic integral free energy of mixing data using Complex formation model. The new method was first used to theoretically compute the γ{sup ∞}s of 10 binary alloys whose γ{sup ∞}s have been determined by experiments. The significant agreement between the computed values and the available experimental values served as impetus for applying the new method to 22 selected binary liquid alloys whose γ{sup ∞}s are either nonexistent or incomplete. In order to verify the reliability of the computed γ{sup ∞}s of the 22 selected alloys, we recomputed the γ{sup ∞}s using three other existing methods of computing or estimating γ{sup ∞}s and then used the γ{sup ∞}s obtained from each of the four methods (the new method inclusive) to compute thermodynamic activities of components of each of the binary systems. The computed activities were compared with available experimental activities. It is observed that the results from the method being proposed, in most of the selected alloys, showed better agreement with experimental activity data. Thus, the new method is an alternative and in certain instances, more reliable approach of computing γ{sup ∞}s of binary liquid alloys.

  15. Evaluation of online carbon isotope dilution mass spectrometry for the purity assessment of synthetic peptide standards

    Energy Technology Data Exchange (ETDEWEB)

    Díaz, Sergio Cueto; Ruiz Encinar, Jorge, E-mail: ruizjorge@uniovi.es; García Alonso, J. Ignacio, E-mail: jiga@uniovi.es

    2014-09-24

    Highlights: • Purity assessment of peptide standards applicable to any water soluble peptide. • Online {sup 13}C isotope dilution mass spectrometry. • Mass flow chromatogram from measured 44/45 isotope ratios. • Validation by the analysis of NIST 8327. - Abstract: We present a novel method for the purity assessment of peptide standards which is applicable to any water soluble peptide. The method is based on the online {sup 13}C isotope dilution approach in which the peptide is separated from its related impurities by liquid chromatography (LC) and the eluent is mixed post-column with a continuous flow of {sup 13}C-enriched sodium bicarbonate. An online oxidation step using sodium persulfate in acidic media at 99 °C provides quantitative oxidation to {sup 12}CO{sub 2} and {sup 13}CO{sub 2} respectively which is extracted to a gaseous phase with the help of a gas permeable membrane. The measurement of the isotope ratio 44/45 in the mass spectrometer allows the construction of the mass flow chromatogram. As the only species that is finally measured in the mass spectrometer is CO{sub 2}, the peptide content in the standard can be quantified, on the base of its carbon content, using a generic primary standard such as potassium hydrogen phthalate. The approach was validated by the analysis of a reference material (NIST 8327), and applied to the quantification of two commercial synthetic peptide standards. In that case, the results obtained were compared with those obtained using alternative methods, such as amino acid analysis and ICP-MS. The results obtained proved the value of the method for the fast, accurate and precise mass purity assignment of synthetic peptide standards.

  16. Preparation of {sup 166} Dy/{sup 166} Ho DTPA-bis biotin as a system of In vivo generator; Preparacion de {sup 166} Dy/{sup 166} Ho DTPA-bis biotina como un sistema de generador In vivo

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez V, M.R

    2003-07-01

    The objective of this work was to synthesize the complex {sup 166} Dy/{sup 166} Ho - diethylen triamine pentaacetic-bis Biotin ({sup 166} Dy/{sup 166} Ho DTPA-bis Biotin) to evaluate its potential as a new radiopharmaceutical in directed radiotherapy. The Dysprosium-166 was obtained for neutron irradiation of {sup 164} Dy{sub 2}0{sub 3} in the TRIGA Mark III reactor. The labelled was carried out in aqueous solution to p H 8.0 for addition of {sup 166} Dy Cl{sub 3} to the diethylen triamine pentaacetic-{alpha}, {omega}-bis Biotin (DTPA-bis Biotin). The radiochemical purity was determined for HPLC and ITLC. The biological integrity of the marked biotin is evaluated by the biological recognition of the avidin for HPLC - molecular exclusion with and without avidin addition. The studies of stability in vitro were made in dilutions of saline solution to 0.9% and with human serum at 37 C incubated 1 and 24 hours. The complex {sup 166} Dy/{sup 166} Ho DTPA-bis Biotin was obtained with a radiochemical purity of 99.1 {+-} 0.6%. The biological recognition of the complex {sup 166} Dy/{sup 166} Ho DTPA-bis Biotin for the avidin it doesn't affect the labelling procedure. The studies in vitro demonstrated that the {sup 166} Dy/{sup 166} Ho DTPA-bis Biotin is stable after the dilution in saline solution and in human serum that there is not translocation of the one radionuclide subsequent son to the beta decay of the {sup 166} Dy that could produce the {sup 166} Ho{sup 3+} liberation. The studies of Biodistribution in healthy mice demonstrated that the one complex {sup 166} Dy/{sup 166} Ho DTPA-bis Biotin have a high renal distribution. In conclusion the radiolabelled biotin in this investigation has the appropriate properties to be used as an In vivo generator system stable for directed radiotherapy. (Author)

  17. Preparation of {sup 166} Dy/{sup 166} Ho DTPA-bis biotin as a system of In vivo generator; Preparacion de {sup 166} Dy/{sup 166} Ho DTPA-bis biotina como un sistema de generador In vivo

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez V, M R

    2003-07-01

    The objective of this work was to synthesize the complex {sup 166} Dy/{sup 166} Ho - diethylen triamine pentaacetic-bis Biotin ({sup 166} Dy/{sup 166} Ho DTPA-bis Biotin) to evaluate its potential as a new radiopharmaceutical in directed radiotherapy. The Dysprosium-166 was obtained for neutron irradiation of {sup 164} Dy{sub 2}0{sub 3} in the TRIGA Mark III reactor. The labelled was carried out in aqueous solution to p H 8.0 for addition of {sup 166} Dy Cl{sub 3} to the diethylen triamine pentaacetic-{alpha}, {omega}-bis Biotin (DTPA-bis Biotin). The radiochemical purity was determined for HPLC and ITLC. The biological integrity of the marked biotin is evaluated by the biological recognition of the avidin for HPLC - molecular exclusion with and without avidin addition. The studies of stability in vitro were made in dilutions of saline solution to 0.9% and with human serum at 37 C incubated 1 and 24 hours. The complex {sup 166} Dy/{sup 166} Ho DTPA-bis Biotin was obtained with a radiochemical purity of 99.1 {+-} 0.6%. The biological recognition of the complex {sup 166} Dy/{sup 166} Ho DTPA-bis Biotin for the avidin it doesn't affect the labelling procedure. The studies in vitro demonstrated that the {sup 166} Dy/{sup 166} Ho DTPA-bis Biotin is stable after the dilution in saline solution and in human serum that there is not translocation of the one radionuclide subsequent son to the beta decay of the {sup 166} Dy that could produce the {sup 166} Ho{sup 3+} liberation. The studies of Biodistribution in healthy mice demonstrated that the one complex {sup 166} Dy/{sup 166} Ho DTPA-bis Biotin have a high renal distribution. In conclusion the radiolabelled biotin in this investigation has the appropriate properties to be used as an In vivo generator system stable for directed radiotherapy. (Author)

  18. Trace uranium analysis in geological sample by isotope dilution-alpha spectrometry and comparison with other techniques

    International Nuclear Information System (INIS)

    Shihomatsu, H.M.; Iyer, S.S.

    1988-12-01

    Establishment of uranium determination in geological samples by alpha spectrometric isotope dilution technique using 233 U tracer is described in the present work. The various steps involved in the method namely, preparation of the sample, electrodeposition, alpha spectrometry, isotope dilution, calculation of the concentration and error statistics are discussed in detail. The experimental parameters for the electrodeposition of uranium, like current density, pH concentration of the electrolyte solution, deposition time, electrode distance were all optimised based on the efficiency of the deposition. The total accuracy and precision of the IDAS using 233 U tracer in the determination of uranium in mineral and granite samples were of the order of 1 to 2% for the concentration range of 50-1500 ppm of U. Our results are compared with those obtained by others workers using similar and different techniques. (author) [pt

  19. Ab initio description of the diluted magnetic semiconductor Ga1-xMnxAs: Ferromagnetism, electronic structure, and optical response

    Science.gov (United States)

    Craco, L.; Laad, M. S.; Müller-Hartmann, E.

    2003-12-01

    Motivated by a study of various experiments describing the electronic and magnetic properties of the diluted magnetic semiconductor Ga1-xMnxAs, we investigate its physical response in detail using a combination of first-principles band structure with methods based on dynamical mean field theory to incorporate strong, dynamical correlations, and intrinsic as well as extrinsic disorder in one single theoretical picture. We show how ferromagnetism is driven by double exchange (DE), in agreement with very recent observations, along with a good quantitative description of the details of the electronic structure, as probed by scanning tunneling microscopy and optical conductivity. Our results show how ferromagnetism can be driven by DE even in diluted magnetic semiconductors with small carrier concentration.

  20. Comparison of Dilution, Filtration, and Microwave Digestion Sample Pretreatments in Elemental Profiling of Wine by ICP-MS.

    Science.gov (United States)

    Godshaw, Joshua; Hopfer, Helene; Nelson, Jenny; Ebeler, Susan E

    2017-09-25

    Wine elemental composition varies by cultivar, geographic origin, viticultural and enological practices, and is often used for authenticity validation. Elemental analysis of wine by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) is challenging due to the potential for non-spectral interferences and plasma instability arising from organic matrix components. Sample preparation mitigates these interferences, however, conflicting recommendations of best practices in ICP-MS analysis of wine have been reported. This study compared direct dilution, microwave-assisted acid digestion, and two filtration sample pretreatments, acidification prior to filtration and filtration followed by acidification, in elemental profiling of one white and three red table wines by ICP-MS. Of 43 monitored isotopes, 37 varied by sample preparation method, with significantly higher results of 17 isotopes in the microwave-digested samples. Both filtration treatments resulted in lower results for 11 isotopes compared to the other methods. Finally, isotope dilution determination of copper based on natural abundances and the 63 Cu: 65 Cu instrument response ratio agreed with external calibration and confirmed a significant sample preparation effect. Overall, microwave digestion did not compare favorably, and direct dilution was found to provide the best compromise between ease of use and result accuracy and precision, although all preparation strategies were able to differentiate the wines.