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Sample records for absorption studies revealed

  1. Absorption studies

    International Nuclear Information System (INIS)

    Ganatra, R.D.

    1992-01-01

    Absorption studies were once quite popular but hardly anyone does them these days. It is easier to estimate the blood level of the nutrient directly by radioimmunoassay (RIA). However, the information obtained by estimating the blood levels of the nutrients is not the same that can be obtained from the absorption studies. Absorption studies are primarily done to find out whether some of the essential nutrients are absorbed from the gut or not and if they are absorbed, to determine how much is being absorbed. In the advanced countries, these tests were mostly done to detect pernicious anaemia where vitamin B 12 is not absorbed because of the lack of the intrinsic factor in the stomach. In the tropical countries, ''malabsorption syndrome'' is quire common. In this condition, several nutrients like fat, folic acid and vitamin B 12 are not absorbed. It is possible to study absorption of these nutrients by radioisotopic absorption studies

  2. Quasar Absorption Studies

    Science.gov (United States)

    Mushotzky, Richard (Technical Monitor); Elvis, Martin

    2004-01-01

    The aim of the proposal is to investigate the absorption properties of a sample of inter-mediate redshift quasars. The main goals of the project are: Measure the redshift and the column density of the X-ray absorbers; test the correlation between absorption and redshift suggested by ROSAT and ASCA data; constrain the absorber ionization status and metallicity; constrain the absorber dust content and composition through the comparison between the amount of X-ray absorption and optical dust extinction. Unanticipated low energy cut-offs where discovered in ROSAT spectra of quasars and confirmed by ASCA, BeppoSAX and Chandra. In most cases it was not possible to constrain adequately the redshift of the absorber from the X-ray data alone. Two possibilities remain open: a) absorption at the quasar redshift; and b) intervening absorption. The evidences in favour of intrinsic absorption are all indirect. Sensitive XMM observations can discriminate between these different scenarios. If the absorption is at the quasar redshift we can study whether the quasar environment evolves with the Cosmic time.

  3. Iron absorption studies

    International Nuclear Information System (INIS)

    Ekenved, G.

    1976-01-01

    The main objective of the present work was to study iron absorption from different iron preparations in different types of subjects and under varying therapeutic conditions. The studies were performed with different radioiron isotope techniques and with a serum iron technique. The preparations used were solutions of ferrous sulphate and rapidly-disintegrating tablets containing ferrous sulphate, ferrous fumarate and ferrous carbonate and a slow-release ferrous sulphate tablet of an insoluble matrix type (Duroferon Durules). The serum iron method was evaluated and good correlation was found between the serum iron response and the total amount of iron absorbed after an oral dose of iron given in solution or in tablet form. New technique for studying the in-vivo release properties of tablets was presented. Iron tablets labelled with a radio-isotope were given to healthy subjects. The decline of the radioactivity in the tablets was followed by a profile scanning technique applied to different types of iron tablets. The release of iron from the two types of tablets was shown to be slower in vivo than in vitro. It was found that co-administration of antacids and iron tablets led to a marked reduction in the iron absorption and that these drugs should not be administered sumultaneously. A standardized meal markedly decreased the absorbability of iron from iron tablets. The influence of the meal was more marked with rapidly-disintegrating than with slow-release ferrous sulphate tablets. The absorption from rapidly-disintegrating and slow-release ferrous sulphate tablets was compared under practical clinical conditions during an extended treatment period. The studies were performed in healthy subjects, blood donors and patients with iron deficiency anaemia and it was found that the absorption of iron from the slow-release tablets was significantly better than from the rapidly-disintegrating tablets in all three groups of subjects. (author)

  4. [Study on lead absorption in pumpkin by atomic absorption spectrophotometry].

    Science.gov (United States)

    Li, Zhen-Xia; Sun, Yong-Dong; Chen, Bi-Hua; Li, Xin-Zheng

    2008-07-01

    A study was carried out on the characteristic of lead absorption in pumpkin via atomic absorption spectrophotometer. The results showed that lead absorption amount in pumpkin increased with time, but the absorption rate decreased with time; And the lead absorption amount reached the peak in pH 7. Lead and cadmium have similar characteristic of absorption in pumpkin.

  5. Combined Spectroscopic and Calorimetric Studies to Reveal Absorption Mechanisms and Conformational Changes of Protein on Nanoporous Biomaterials

    Directory of Open Access Journals (Sweden)

    Saharnaz Ahmadi

    2015-07-01

    Full Text Available In this study the effect of surface modification of mesoporous silica nanoparticles (MSNs on its adsorption capacities and protein stability after immobilization of beta-lactoglobulin B (BLG-B was investigated. For this purpose, non-functionalized (KIT-6 and aminopropyl-functionalized cubic Ia3d mesoporous silica ([n-PrNH2-KIT-6] nanoparticles were used as nanoporous supports. Aminopropyl-functionalized mesoporous nanoparticles exhibited more potential candidates for BLG-B adsorption and minimum BLG leaching than non-functionalized nanoparticles. It was observed that the amount of adsorbed BLG is dependent on the initial BLG concentration for both KIT-6 and [n-PrNH2-KIT-6] mesoporous nanoparticles. Also larger amounts of BLG-B on KIT-6 was immobilized upon raising the temperature of the medium from 4 to 55 °C while such increase was undetectable in the case of immobilization of BLG-B on the [n-PrNH2-KIT-6]. At temperatures above 55 °C the amounts of adsorbed BLG on both studied nanomaterials decreased significantly. By Differential scanning calorimetry or DSC analysis the heterogeneity of the protein solution and increase in Tm may indicate that immobilization of BLG-B onto the modified KIT-6 results in higher thermal stability compared to unmodified one. The obtained results provide several crucial factors in determining the mechanism(s of protein adsorption and stability on the nanostructured solid supports and the development of engineered nano-biomaterials for controlled drug-delivery systems and biomimetic interfaces for the immobilization of living cells.

  6. Uranium absorption study pile

    International Nuclear Information System (INIS)

    Raievski, V.; Sautiez, B.

    1959-01-01

    The report describes a pile designed to measure the absorption of fuel slugs. The pile is of graphite and comprises a central section composed of uranium rods in a regular lattice. RaBe sources and BF 3 counters are situated on either side of the center. A given uranium charge is compared with a specimen charge of about 560 kg, and the difference in absorption between the two noted. The sensitivity of the equipment will detect absorption variations of about a few ppm boron (10 -6 boron per gr. of uranium) or better. (author) [fr

  7. A method optimization study for atomic absorption ...

    African Journals Online (AJOL)

    A sensitive, reliable and relative fast method has been developed for the determination of total zinc in insulin by atomic absorption spectrophotometer. This designed study was used to optimize the procedures for the existing methods. Spectrograms of both standard and sample solutions of zinc were recorded by measuring ...

  8. A transient absorption study of allophycocyanin

    Indian Academy of Sciences (India)

    Transient dynamics of allophycocyanin trimers and monomers are observed by using the pump-probe, transient absorption technique. The origin of spectral components of the transient absorption spectra is discussed in terms of both kinetics and spectroscopy. We find that the energy gap between the ground and excited ...

  9. Studies of fat absorption using radioiodinated triolein

    International Nuclear Information System (INIS)

    Nelp, W.B.

    1976-01-01

    Fat absorption has been classically measured by comparing the fat content of the faeces with that of the diet, using chemical assay methods, and this procedure is usually assumed to give the ''right'' answer which the results of other methods should approach. The care and expense associated with the balance method, however, have led to the development of other methods, notably the use of 131 I-triolein as a tracer for fat. This technique has often given poor agreement with the chemical method, and the possible reasons therefore include: errors in the balance method, radiochemical impurity of the 131 I-triolein preparation, and faulty technique with 131 I-triolein. This paper reviews these sources of error and their importance in a series of tests on 44 subjects. It is concluded that the 131 I-triolein test does have diagnostic utility, and further studies may show this to be greatest when faecal excretion of 131 I activity is compared with that of a simultaneously administered non-absorbable marker such as 131 Ba. (author)

  10. A method optimization study for atomic absorption ...

    African Journals Online (AJOL)

    Sadia Ata

    2014-04-24

    Apr 24, 2014 ... Manufacturer brand Win 2.1 software was used for data inte- gration and processing. ... reagents and analyst) is suitable for the intended application. The % relative standard deviation for absorbance ... flame atomic absorption spectrometry. Table 2 Linearity data for analysis of zinc in insulin using AAS.

  11. A cylindrical furnace for absorption spectral studies

    Indian Academy of Sciences (India)

    A cylindrical furnace with three heating zones, capable of providing a temperature of 1100°C, has been fabricated to enable recording of absorption spectra of high temperature species. The temperature of the furnace can be controlled to ± 1°C of the set temperature. The salient feature of this furnace is that the material ...

  12. Numerical study of surface plasmon enhanced nonlinear absorption and refraction.

    Science.gov (United States)

    Kohlgraf-Owens, Dana C; Kik, Pieter G

    2008-07-07

    Maxwell Garnett effective medium theory is used to study the influence of silver nanoparticle induced field enhancement on the nonlinear response of a Kerr-type nonlinear host. We show that the composite nonlinear absorption coefficient, beta(c), can be enhanced relative to the host nonlinear absorption coefficient near the surface plasmon resonance of silver nanoparticles. This enhancement is not due to a resonant enhancement of the host nonlinear absorption, but rather due to a phase shifted enhancement of the host nonlinear refractive response. The enhancement occurs at the expense of introducing linear absorption, alpha(c), which leads to an overall reduced figure of merit beta(c)/alpha(c) for nonlinear absorption. For thin (< 1 microm) composites, the use of surface plasmons is found to result in an increased nonlinear absorption response compared to that of the host material.

  13. Studies on Steam Absorption Chillers Performance at a Cogeneration Plant

    Directory of Open Access Journals (Sweden)

    Abd Majid Mohd Amin

    2014-07-01

    Full Text Available Absorption chillers at cogeneration plants generate chilled water using steam supplied by heat recovery steam generators. The chillers can be of either single-effect or double effect configuration and the coefficient of performance (COP depends on the selection made. The COP varies from 0.7 to 1.2 depending on the types of chillers. Single effect chillers normally have COP in the range of 0.68 to 0.79. Double effect chillers COP are higher and can reach 1.2. However due to factors such as inappropriate operations and maintenance practices, COP could drop over a period of time. In this work the performances of double effect steam absorption chillers at a cogeneration plant were studied. The study revealed that during the period of eleven years of operation the COP of the chillers deteriorated from 1.25 to 0.6. Regression models on the operation data indicated that the state of deterioration was projected to persist. Hence, it would be recommended that the chillers be considered for replacement since they had already undergone a series of costly repairs.

  14. Absorption anisotropy studies of polymethine dyes

    International Nuclear Information System (INIS)

    Lepkowicz, Richard S.; Cirloganu, Claudiu M.; Przhonska, Olga V.; Hagan, David J.; Van Stryland, Eric W.; Bondar, Mikhail V.; Slominsky, Yuriy L.; Kachkovski, Alexei D.; Mayboroda, Elena I.

    2004-01-01

    The determination of the spectral position of the excited states and orientation of the transition dipole moments of polymethine molecules is experimentally measured using two methods: the steady-state fluorescence anisotropy method, and a two-color polarization-resolved pump-probe method. This novel use of the pump-probe method is described in detail and a comparison to the fluorescence method is given. Quantum-chemical modeling on the effects of the bridge structure in the polymethine chromophore on the linear absorption spectrum is also discussed

  15. Attenuation studies near K-absorption edges using Compton ...

    Indian Academy of Sciences (India)

    The results are consistent with theoretical values derived from the XCOM package. Keywords. Photon interaction; 241Am; gamma ray attenuation; Compton scattering; absorption edge; rare earth elements. PACS Nos 32.80.-t; 32.90.+a. 1. Introduction. Photon interaction studies at energies around the absorption edge have ...

  16. Microwave absorption studies of MgB 2 superconductor

    Indian Academy of Sciences (India)

    Microwave absorption studies have been carried out on MgB2 superconductor using a standard X-band EPR spectrometer. The modulated low-field microwave absorption signals recorded for polycrystalline (grain size ∼ 10m) samples suggested the absence of weak-link character. The field dependent direct microwave ...

  17. Studies on absorption coefficient near edge of multi elements

    International Nuclear Information System (INIS)

    Eisa, M.H.; Shen, H.; Yao, H.Y.; Mi, Y.; Zhou, Z.Y.; Hu, T.D.; Xie, Y.N.

    2005-01-01

    X-ray absorption near edge structure (XANES) was used to study the near edge mass-absorption coefficients of seven elements, such as, Ti, V, Fe, Co, Ni, Cu and Zn. It is well known that, on the near edge absorption of element, when incident X-ray a few eV change can make the absorption coefficient an order magnitude alteration. So that, there are only a few points mass-absorption coefficient at the near edge absorption and that always average value in published table. Our results showed a wide range of data, the total measured data of mass-absorption coefficient of the seven elements was about 505. The investigation confirmed that XANES is useful technique for multi-element absorption coefficient measurement. Details of experimental methods and results are given and discussed. The experimental work has been performed at Beijing Synchrotron Radiation Facility. The measured values were compared with the published data. Good agreement between experimental results and published data is obtained

  18. Studies on absorption coefficient near edge of multi elements

    Science.gov (United States)

    Eisa, M. H.; Shen, H.; Yao, H. Y.; Mi, Y.; Zhou, Z. Y.; Hu, T. D.; Xie, Y. N.

    2005-12-01

    X-ray absorption near edge structure (XANES) was used to study the near edge mass-absorption coefficients of seven elements, such as, Ti, V, Fe, Co, Ni, Cu and Zn. It is well known that, on the near edge absorption of element, when incident X-ray a few eV change can make the absorption coefficient an order magnitude alteration. So that, there are only a few points mass-absorption coefficient at the near edge absorption and that always average value in published table. Our results showed a wide range of data, the total measured data of mass-absorption coefficient of the seven elements was about 505. The investigation confirmed that XANES is useful technique for multi-element absorption coefficient measurement. Details of experimental methods and results are given and discussed. The experimental work has been performed at Beijing Synchrotron Radiation Facility. The measured values were compared with the published data. Good agreement between experimental results and published data is obtained.

  19. UV absorption reveals mycosporine-like amino acids (MAAs in Tatra mountain lake phytoplankton

    Directory of Open Access Journals (Sweden)

    Jerzy Dera

    2013-08-01

    Full Text Available Enhanced absorption of UV radiation, an effect characteristic of mycosporine-like amino acids (MAAs, is reported in samples of phytoplankton from six lakes in the Tatra Mountains National Park (Poland. It was demonstrated that the mass-specific UV absorption coefficients for the phytoplankton in these lakes increased with altitude above sea level. Based on a comparison with the phytoplankton of Alpine lakes, investigated earlier by other authors (cited in this paper, it may be inferred that the phytoplankton of Tatra mountain lakes produce MAAs, which protect plant cells from UV light, the intensity of which increases with altitude.

  20. Absorption heat cycles. An experimental and theoretical study

    International Nuclear Information System (INIS)

    Abrahamsson, K.

    1993-09-01

    A flow sheeting programme, SHPUMP, was developed for simulating different absorption heat cycles. The programme consists of ten different modules which allow the user to construct his own absorption cycle. The ten modules configurate evaporators, absorbers, generators, rectifiers, condensers, solution heat exchangers, pumps, valves, mixers and splitters. Seven basic and well established absorption cycles are available in the configuration data base of the programme. A new Carnot model is proposed heat cycles. Together with exergy analysis, general equations for the Carnot coefficient of performance and equations for thermodynamic efficiency, exergetic efficiency and exergy index, are derived, discussed and compared for both absorption heat pumps and absorption heat transformers. Utilizing SHPUMP, simulation results are presented for different configurations where absorption heat cycles are suggested to be incorporated in three different unit operations within both pulp and paper and oleochemical industries. One of the application studies reveled that an absorption heat transformer incorporated with an evaporation plant in a major pulp and paper industry, would save 18% of the total prime energy consumption in one of the evaporation plants. It was also concluded that installing an absorption heat pump in a paper drying plant would result in steam savings equivalent to 12 MW. An experimental absorption heat transformer unit operating with self-circulation has been modified and thoroughly tested. A reference heat transformer plant has been designed and installed in a major pulp and paper mill where it is directly incorporated with one of the evaporation plants. Preliminary plant operation data are presented. 72 refs, 63 figs, 33 tabs

  1. NuSTAR Reveals Extreme Absorption in z < 0.5 Type 2 Quasars

    Science.gov (United States)

    Lansbury, G. B.; Gandhi, P.; Alexander, D. M.; Assef, R. J.; Aird, J.; Annuar, A.; Ballantyne, D. R.; Baloković, M.; Bauer, F. E.; Boggs, S. E.; Brandt, W. N.; Brightman, M.; Christensen, F. E.; Civano, F.; Comastri, A.; Craig, W. W.; Del Moro, A.; Grefenstette, B. W.; Hailey, C. J.; Harrison, F. A.; Hickox, R. C.; Koss, M.; LaMassa, S. M.; Luo, B.; Puccetti, S.; Stern, D.; Treister, E.; Vignali, C.; Zappacosta, L.; Zhang, W. W.

    2015-08-01

    The intrinsic column density (NH) distribution of quasars is poorly known. At the high obscuration end of the quasar population and for redshifts z 1.5 × 1024 cm-2) type 2 quasars (CTQSO2s); five new NuSTAR observations are reported herein, and four have been previously published. The candidate CTQSO2s lie at z < 0.5, have observed [O iii] luminosities in the range 8.4\\lt {log}({L}[{{O} {{III}}]}/{L}⊙ )\\lt 9.6, and show evidence for extreme, Compton-thick absorption when indirect absorption diagnostics are considered. Among the nine candidate CTQSO2s, five are detected by NuSTAR in the high-energy (8-24 keV) band: two are weakly detected at the ≈3σ confidence level and three are strongly detected with sufficient counts for spectral modeling (≳90 net source counts at 8-24 keV). For these NuSTAR-detected sources direct (i.e., X-ray spectral) constraints on the intrinsic active galactic nucleus properties are feasible, and we measure column densities ≈2.5-1600 times higher and intrinsic (unabsorbed) X-ray luminosities ≈10-70 times higher than pre-NuSTAR constraints from Chandra and XMM-Newton. Assuming the NuSTAR-detected type 2 quasars are representative of other Compton-thick candidates, we make a correction to the NH distribution for optically selected type 2 quasars as measured by Chandra and XMM-Newton for 39 objects. With this approach, we predict a Compton-thick fraction of {f}{CT}={36}-12+14 %, although higher fractions (up to 76%) are possible if indirect absorption diagnostics are assumed to be reliable.

  2. Alcohol-catalyzed photoreduction of iron-porphyrin complexes revealed by resonance raman and absorption spectroscopies

    Science.gov (United States)

    Ogura, T.; Fidler, V.; Ozaki, Y.; Kitagawa, T.

    1990-06-01

    Photoreduction of Fe III(OEP) (2-MeIm) (OEP is octaethylporphyrin; 2-MeIm is 2-methylimidazole) was found to be catalyzed by a trace amount of MeOH present in Ch 2Cl 2 as a stabilizer. The absence of either 2-MeIm or MeOH in the CH 2Cl 2 solution of Fe III(OEP) X (X is Cl -, Br - or I -) leads to no photoreduction. The presence of MeOH in the Fe III(OEP) (2-MeIm) solution results in the appearance of a new absorption band at 585 nm, and when Raman scattering was excited at 590 nm, a new Raman band appeared at 524 cm -. This band exhibited an upshift by 4 cm - with 54Fe(OEP) (2-MeIm)(CH 3OH) and a downshift by 12 cm -1 with 56Fe(OEP)(2-MeIm) (CD 3OD) and was therefore assigned to the Fe III-MeOH stretching vibration. The excitation profile of this band gave a peak around 585 nm and accordingly, the new absorption band at 584 nm was assigned to a charge-transfer (CT) band from MeOH to the Fe III ion. It was most unexpected that the photoreduction did not occur upon laser illumination within the CT band.

  3. In vivo studies of biotin absorption in distal rat intestine

    International Nuclear Information System (INIS)

    Bowman, B.B.; Rosenberg, I.H.

    1986-01-01

    The authors have extended their previous studies of biotin absorption in rat proximal jejunum (PJ) to examine biotin absorptive capacity of rat ileum (I) and proximal colon (PC) using in vivo intestinal loop technique. Intestinal loops (2.5 cm) were filled with 0.3 ml of solution containing ( 3 H)-biotin and ( 14 C)-inulin in phosphate buffer, pH 6.5. Biotin absorption was determined on the basis of luminal biotin disappearance after correction for inulin recovery and averaged (pmol/loop-10 min; X +/- SEM). In related experiments, 5-cm loops of PJ, distal I (DI), or PC were filled with 0.5 ml of solution of similar composition (1.0 μM biotin). The abdominal cavity was closed and the rats were allowed to recover from anesthesia, then sacrificed 3 hr after injection. Biotin absorption averaged 96.2% (PJ), 93.2% (DI), and 25.8% (PC) of the dose administered. These differences were reflected in the radioactive biotin content of plasma and intestinal loop, kidney, and liver. These data demonstrate significant biotin absorption in rat DI and PC, as required if the intestinal microflora are to be considered as a source of biotin for the host

  4. Study of /sup 137/Cs absorption by Lemna minor

    Energy Technology Data Exchange (ETDEWEB)

    Bergamini, P G; Palmas, G; Piantelli, F; Sani, M [Siena Univ. (Italy). Ist. di Fisica; Banditelli, P; Previtera, M; Sodi, F

    1979-09-01

    Absorption of /sup 137/Cs by the floating aquatic plant Lemna minor in relation to /sup 137/Cs concentration in the water was measured under controlled conditions of temperature, pH and light. The method used to analyse the results is described. When applied to this study the method shows the influence on /sup 137/Cs absorption of (1) potassium-cesium exchange due to chemical affinity, (2) the natural colony growth of the organism and (3) the effect of light. Concentration factors were determined for these three processes.

  5. Study of 137Cs absorption by Lemna minor

    International Nuclear Information System (INIS)

    Bergamini, P.G.; Palmas, G.; Piantelli, F.; Sani, M.; Banditelli, P.; Previtera, M.; Sodi, F.

    1979-01-01

    Absorption of 137 Cs by the floating aquatic plant Lemna Minor in relation to 137 Cs concentration in the water was measured under controlled conditions of temperature, pH and light. The method used to analyse the results is described. When applied to this study the method shows the influence on 137 Cs absorption of (1) potassium-cesium exchange due to chemical affinity, (2) the natural colony growth of the organism and (3) the effect of light. Concentration factors were determined for these three processes. (author)

  6. Cognitive distance, absorptive capacity and group rationality : a simulation study

    NARCIS (Netherlands)

    Curseu, P.L.; Krehel, O.; Evers, J.H.M.; Muntean, A.

    2014-01-01

    We report the results of a simulation study in which we explore the joint effect of group absorptive capacity (as the average individual rationality of the group members) and cognitive distance (as the distance between the most rational group member and the rest of the group) on the emergence of

  7. Cognitive distance, absorptive capacity and group rationality : A simulation study

    NARCIS (Netherlands)

    Curseu, P.L.; Krehel, O.; Evers, J.H.M.; Muntean, A.

    2014-01-01

    We report the results of a simulation study in which we explore the joint effect of group absorptive capacity (as the average individual rationality of the group members) and cognitive distance (as the distance between the most rational group member and the rest of the group) on the emergence of

  8. Non-resonant microwave absorption studies of superconducting ...

    Indian Academy of Sciences (India)

    Abstract. Non-resonant microwave absorption (NRMA) studies of superconducting MgB2 and a sample containing 10% by weight of MgO in MgB2 are reported. The NRMA results indicate near absence of intergranular weak links in the pure MgB2 sample. A linear temperature dependence of the lower critical field Hc1 is ...

  9. Radioisotope studies for quantitative measurement of manganese absorption

    International Nuclear Information System (INIS)

    Helbig, U.

    1981-01-01

    Purpose of the present study was to quantitatively determine the manganese absorption in growing rats by means of radioisotopes. First of all the following factors had to be investigated, which are significant for this determination: Measurability of stable and radioactive Mn in rat tissues; labelling of stable Mn and distribution of stable and radioactive Mn in the organism; verification of the isotope dilution method and of the comparative balance method with regard to its applicability for the determination of the true Mn absorption. We useed male and female Sprague-Dawley rats. The most important results are summarized in the following: in some separate tissues measurement of stable Mn was accompanied by difficulties. The measurement of radioactive Mn however, could be performed without any problems. 10 d after i.m. injection of 54 Mn only 17% of the administered Mn was still detectable in the organism. However, there was no uniform tissue labelling found. Therefore it is possible to an only restricted extent to draw quantitative conclusions on the content of stable Mn. A high percentage of stable and radioactive Mn was found above all in the liver. The isotope dilution method permits by feces analysis to differentiate between unabsorbed Mn coming from the food and endogenic Mn coming from the organism itself. The effective Mn absorption was also determined by means of the comparative balance method. By means of the isotope dilution method we determined the quantitative Mn-absorption with staged Mn administration and the contribution of absorption and excretion to the homeostatic regulation mechanisms of Mn. We found that absorption and excretion help the organism to keep an almost constant Mn concentration even with a differing Mn supply. (orig./MG) [de

  10. Effects of Omeprazole on Iron Absorption: Preliminary Study

    Directory of Open Access Journals (Sweden)

    Mahmut Yaşar Çeliker

    2013-09-01

    Full Text Available Objective: Increasing numbers of pediatric and adult patients are being treated with proton pump inhibitors (PPIs. PPIs are known to inhibit gastric acid secretion. Nonheme iron requires gastric acid for conversion to the ferrous form for absorption. Ninety percent of dietary and 100% of oral iron therapy is in the nonheme form. To the best of our knowledge, the effect of PPIs on iron absorption has not been studied in humans. Our study assessed the relationship between omeprazole therapy and iron absorption in healthy subjects. Materials and Methods: We recruited 9 healthy volunteers between June 2010 and March 2011. Subjects with chronic illness, anemia, or use of PPI therapy were excluded. Serum iron concentrations were measured 1, 2, and 3 h after the ingestion of iron (control group. The measurements were repeated on a subsequent visit after 4 daily oral administrations of omeprazole at a dose of 40 mg (treatment group. Results: One female and 8 male volunteers were enrolled in the study with a mean age of 33 years. There was no statistical difference detected between baseline, 1-h, 2-h, and 3-h iron levels between control and treatment groups. Conclusion: Administration of omeprazole for a short duration does not affect absorption of orally administered iron in healthy individuals.

  11. The Nature of the Vela Supernova Remnant as Revealed by O VI and C IV Absorption

    Science.gov (United States)

    Lines, Nichols J.; Slavin, J.; Anderson, C.

    2001-01-01

    Highly ionized gas, in particular C IV and O VI, is produced in the interstellar medium in regions with hot (T approx. 10(exp 6) K) X-ray emitting gas and at the boundaries where hot gas and cooler (T approx. 10(exp 4) K) gas interact. Supernova remnant shocks produce most of the hot gas in the ISM and, if they are in the correct range of speeds, should produce observable quantities of C IV and O VI absorption. In turn, the column densities of these ions are potentially powerful diagnostics of the shock speed and interstellar environment in which the SNR is evolving. With the advent of FUSE, the power of this diagnostic technique is now available. We have FUSE data toward 8 stars behind the Vela SNR, and have developed a data reduction and analysis method that produces reasonably reliable O VI column densities, in spite of the complexities of the FUSE spectra in this region. In order to gain insight into the observational results, the Vela SNR evolution was modelled using Piecewise Parabolic Method numerical hydrodynamics code. The code is 1-D and incorporates non-equilibrium ionization, radiative cooling, thermal conduction and magnetic pressure.

  12. Bimodal Exciplex Formation in Bimolecular Photoinduced Electron Transfer Revealed by Ultrafast Time-Resolved Infrared Absorption.

    Science.gov (United States)

    Koch, Marius; Licari, Giuseppe; Vauthey, Eric

    2015-09-03

    The dynamics of a moderately exergonic photoinduced charge separation has been investigated by ultrafast time-resolved infrared absorption with the dimethylanthracene/phthalonitrile donor/acceptor pair in solvents covering a broad range of polarity. A distinct spectral signature of an exciplex could be identified in the -C≡N stretching region. On the basis of quantum chemistry calculations, the 4-5 times larger width of this band compared to those of the ions and of the locally excited donor bands is explained by a dynamic distribution of exciplex geometry with different mutual orientations and distances of the constituents and, thus, with varying charge-transfer character. Although spectrally similar, two types of exciplexes could be distinguished by their dynamics: short-lived, "tight", exciplexes generated upon static quenching and longer-lived, "loose", exciplexes formed upon dynamic quenching in parallel with ion pairs. Tight exciplexes were observed in all solvents, except in the least polar diethyl ether where quenching is slower than diffusion. The product distribution of the dynamic quenching depends strongly on the solvent polarity: whereas no significant loose exciplex population could be detected in acetonitrile, both exciplex and ion pair are generated in less polar solvents, with the relative population of exciplex increasing with decreasing solvent polarity. These results are compared with those reported previously with donor/acceptor pairs in different driving force regimes to obtain a comprehensive picture of the role of the exciplexes in bimolecular photoinduced charge separation.

  13. SOME SPECIATION STUDIES IN FOODSTUFF BY ATOMIC ABSORPTION SPECTROMETRY

    OpenAIRE

    Gücer, S

    2000-01-01

    There has been increasing interest in speciation studies of essentialelements in foods. The main limitation of this studies, their levels in foodsamples and the difficulties for the determination in their own differentforms without any changes in their original forms.Atomic Absorption Spectrometry (AAS) coupled with separation methodswould be outline in this presentation. Analytical scheme was given for tea, olive and garlic samples forManganese, Magnesium and Selenium respectively. Activated...

  14. Study of tunneling time with Larmor clock and neutron absorption

    International Nuclear Information System (INIS)

    Hino, M.; Tasaki, S.; Ebisawa, T.; Kawai, T.; Utsuro, M.; Achiwa, N.

    2001-01-01

    Tunnel effect is one of the most typical quantum mechanical phenomena which cannot be understood in the classical physics. Though the tunnel phenomenon itself is precisely defined on the basis of quantum mechanics, tunneling time, the time for a particle to pass a tunnel barrier, has been a controversial issue because time is a parameter to show the rate of change of physical phenomena in quantum mechanics but has no corresponding quantum operator. In the present study, Larmor precession of the neutrons passing a Permalloy45 (PA) thin film was measured as a function of neutron incident angle to the film by using neutron spin-echo instrument at KUR and neutron interferometer at JRR-3. Results are compared with a calculation based on one-dimensional Schroedinger equation. The agreement between the experiment and the plane-wave simulation is very good which means that the neutrons are not described in particle picture here, and the Larmor time defined as number of spin precession divided by angular velocity no more represents the time for a particle to pass the barrier although it is a kind of the phase time. In order to emphasize the particle picture, effects of neutron absorption were considered theoretically. Larmor precession passing through a Fabry-Perot magnetic thin film which has two potential barriers (quantum well) for up-spin neutrons were measured for two cases that the film is hot neutron absorptive (PA-Ge-PA) and strongly absorptive (Se-Ge/Gd-Se). Here Ge, Gd and Se represent germanium, gadolinium and Supersendust, respectively. While down-spin neutrons feel only a small potential barrier. Spin-dependent reflectivity and transmission of the Fabry-Perot magnetic films were also measured as functions of the neutron incident angle to the film. Experimental results of the non-absorptive film show that the neutron spin precession cannot be treated as the classical motion of a magnetic moment feeling torque under applied magnetic field like the Larmor

  15. Experimental studies of a zeeman-tuned xenon laser differential absorption apparatus.

    Science.gov (United States)

    Linford, G J

    1973-06-01

    A Zeeman-tuned cw xenon laser differential absorption device is described. The xenon laser was tuned by axial magnetic fields up to 5500 G generated by an unusually large water-cooled dc solenoid. Xenon laser lines at 3.37 micro, 3.51 micro, and 3.99 micro were tuned over ranges of 6 A, 6 A, and 11 A, respectively. To date, this apparatus has been used principally to study the details of formaldehyde absorption lines lying near the 3 .508-micro xenon laser transition. These experiments revealed that the observed absorption spectrum of formaldehyde exhibits a sufficiently unique spectral structure that the present technique may readily be used to measure relative concentrations of formaldehyde in samples of polluted air.

  16. Intestinal perfusion in the study of intestinal absorption

    International Nuclear Information System (INIS)

    Baker, S.J.

    1976-01-01

    Several techniques for studying absorption by means of intestinal perfusion have been developed. While the principle is simple, the practice is complicated by absorption of the solvent and by excretion of fluid into the lumen. To improve reliability a ''marker'' is incorporated into the system; it should behave as nearly as possible like the nutrient of interest, except that it should be unabsorbable. A great many markers, including several labelled with radionuclides, have been developed for use with numerous nutrients, and perfusion methods using double or triple tubes or occlusive balloons have been tested. The perfusion technique is too complicated for routine diagnostic use, but it offers at present the only possibility of studying the function of defined sections of the small intestine in the intact human. (author)

  17. Studies on the intestinal absorption of vitamin B2

    International Nuclear Information System (INIS)

    Yamaguchi, Keiko; Moriwaki, Chiaki

    1978-01-01

    The intestinal absorption of vitamin B 2 was studied by in situ mesenteric perfusion system. Free form riboflavin (FR), FMN and FAD (1 mg each) were injected into the ligated jejunum of rat which was infused Krebs Ringer bicarbonate solution from the superior mesenteric artery. Perfusate was recovered from the mesenteric vein and the recoveries of the total riboflavin during 120 min after the administration of these 3 types vitamin B 2 were 1.0, 1.5 and 2.8%, respectively. Furthermore, riboflavin and its esters were detected in the perfusates from 14 C-FR and 14 C-FAD given rats. There was a considerable amount of labeled substance which was not vitamin B 2 derivatives in the radiopaperchromatogram of the perfusate of 14 C-FR dosed rats, and it is suggested that a portion of riboflavin is decomposed in the process of absorption. (auth.)

  18. Spectroscopic study of low-temperature hydrogen absorption in palladium

    Energy Technology Data Exchange (ETDEWEB)

    Ienaga, K., E-mail: ienaga@issp.u-tokyo.ac.jp; Takata, H.; Onishi, Y.; Inagaki, Y.; Kawae, T. [Department of Applied Quantum Physics, Faculty of Engineering, Kyushu University, Motooka, Nishi-Ku, Fukuoka 819-0395 (Japan); Tsujii, H. [Department of Physics, Faculty of Education, Kanazawa University, Kakuma-machi, Kanazawa 920-1192 (Japan); Kimura, T. [Department of Physics, Kyushu University, Hakozaki, Higashi-Ku, Fukuoka 812-8581 (Japan)

    2015-01-12

    We report real-time detection of hydrogen (H) absorption in metallic palladium (Pd) nano-contacts immersed in liquid H{sub 2} using inelastic electron spectroscopy (IES). After introduction of liquid H{sub 2}, the spectra exhibit the time evolution from the pure Pd to the Pd hydride, indicating that H atoms are absorbed in Pd nano-contacts even at the temperature where the thermal process is not expected. The IES time and bias voltage dependences show that H absorption develops by applying bias voltage 30 ∼ 50 mV, which can be explained by quantum tunneling. The results represent that IES is a powerful method to study the kinetics of high density H on solid surface.

  19. Cognitive distance, absorptive capacity and group rationality: a simulation study.

    Directory of Open Access Journals (Sweden)

    Petru Lucian Curşeu

    Full Text Available We report the results of a simulation study in which we explore the joint effect of group absorptive capacity (as the average individual rationality of the group members and cognitive distance (as the distance between the most rational group member and the rest of the group on the emergence of collective rationality in groups. We start from empirical results reported in the literature on group rationality as collective group level competence and use data on real-life groups of four and five to validate a mathematical model. We then use this mathematical model to predict group level scores from a variety of possible group configurations (varying both in cognitive distance and average individual rationality. Our results show that both group competence and cognitive distance are necessary conditions for emergent group rationality. Group configurations, in which the groups become more rational than the most rational group member, are groups scoring low on cognitive distance and scoring high on absorptive capacity.

  20. Cognitive distance, absorptive capacity and group rationality: a simulation study.

    Science.gov (United States)

    Curşeu, Petru Lucian; Krehel, Oleh; Evers, Joep H M; Muntean, Adrian

    2014-01-01

    We report the results of a simulation study in which we explore the joint effect of group absorptive capacity (as the average individual rationality of the group members) and cognitive distance (as the distance between the most rational group member and the rest of the group) on the emergence of collective rationality in groups. We start from empirical results reported in the literature on group rationality as collective group level competence and use data on real-life groups of four and five to validate a mathematical model. We then use this mathematical model to predict group level scores from a variety of possible group configurations (varying both in cognitive distance and average individual rationality). Our results show that both group competence and cognitive distance are necessary conditions for emergent group rationality. Group configurations, in which the groups become more rational than the most rational group member, are groups scoring low on cognitive distance and scoring high on absorptive capacity.

  1. $\\beta$-decay studies using total-absorption spectroscopy

    CERN Document Server

    Algora, A; García-Borge, M J; Cano-Ott, D; Collatz, R; Courtin, S; Dessagne, P; Fraile-Prieto, L M; Gadea, A; Gelletly, W; Hellström, M; Janas, Z; Jungclaus, A; Kirchner, R; Karny, M; Le Scornet, G; Miehé, C; Maréchal, F; Moroz, F; Nacher, E; Poirier, E; Roeckl, E; Rubio, B; Rykaczewski, K; Taín, J L; Tengblad, O; Wittmann, V

    2004-01-01

    $\\beta$-decay experiments are a primary source of information for nuclear-structure studies and at the same time complementary to in- beam investigations of nuclei far from stability. Although both types of experiment are mainly based on $\\gamma$-ray spectroscopy, they face different experimental problems. The so-called " Pandemonium effect " is a critical problem in $\\beta$-decay if we are to test theoretically calculated transition probabilities. In this contribution we will present a solution to this problem using total absorption spectroscopy methods. We will also present some examples of experiments carried out with the Total Absorption Spectrometer (TAS) at GSI and describe a new device LUCRECIA recently installed at CERN.

  2. Uranium absorption study pile; Empilement pour le controle de l'absorption de l'uranium

    Energy Technology Data Exchange (ETDEWEB)

    Raievski, V; Sautiez, B [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1959-07-01

    The report describes a pile designed to measure the absorption of fuel slugs. The pile is of graphite and comprises a central section composed of uranium rods in a regular lattice. RaBe sources and BF{sub 3} counters are situated on either side of the center. A given uranium charge is compared with a specimen charge of about 560 kg, and the difference in absorption between the two noted. The sensitivity of the equipment will detect absorption variations of about a few ppm boron (10{sup -6} boron per gr. of uranium) or better. (author) [French] Nous decrivons un dispositif permettant de mesurer l'absorption des elements combustibles d'une pile. Ce dispositif est constitue par un empilement de graphite dont la region centrale est formee par un reseau regulier de barres d'uranium. Des sources de RaBe et des compteurs a BF{sub 3} sont places de part et d'autre de cette region. En comparant un chargement d'uranium a un chargement etalon d'environ 560 kg, on peut determiner la difference d'absorption entre ces deux chargements. La sensibilite permettrait de deceler une variation d'absorption de l'ordre du ppm de bore (10{sup -6} g de bore par gramme d'uranium) et peut-etre mieux. (auteur)

  3. Multi-mode interference revealed by two photon absorption in silicon rich SiO2 waveguides

    International Nuclear Information System (INIS)

    Manna, S.; Ramiro-Manzano, F.; Mancinelli, M.; Turri, F.; Pavesi, L.; Ghulinyan, M.; Pucker, G.

    2015-01-01

    Photoluminescence (PL) from Si nanocrystals (NCs) excited by two-photon absorption (TPA) has been observed in Si nanocrystal-based waveguides fabricated by plasma enhanced chemical vapor deposition. The TPA excited photoluminescence emission resembles the one-photon excited photoluminescence arising from inter-band transitions in the quantum confined Si nanocrystals. By measuring the non-linear transmission of waveguides, a large TPA coefficient of β up to 10 −8  cm/W has been measured at 1550 nm. These values of β depend on the Si NCs size and are two orders of magnitude larger than the bulk silicon value. Here, we propose to use the TPA excited visible PL emission as a tool to map the spatial intensity profile of the 1550 nm propagating optical modes in multimode waveguides. In this way, multimode interference has been revealed experimentally and confirmed through a finite element simulation

  4. Gas phase absorption studies of photoactive yellow protein chromophore derivatives.

    Science.gov (United States)

    Rocha-Rinza, Toms; Christiansen, Ove; Rajput, Jyoti; Gopalan, Aravind; Rahbek, Dennis B; Andersen, Lars H; Bochenkova, Anastasia V; Granovsky, Alexander A; Bravaya, Ksenia B; Nemukhin, Alexander V; Christiansen, Kasper Lincke; Nielsen, Mogens Brøndsted

    2009-08-27

    Photoabsorption spectra of deprotonated trans p-coumaric acid and two of its methyl substituted derivatives have been studied in gas phase both experimentally and theoretically. We have focused on the spectroscopic effect of the location of the two possible deprotonation sites on the trans p-coumaric acid which originate to either a phenoxide or a carboxylate. Surprisingly, the three chromophores were found to have the same absorption maximum at 430 nm, in spite of having different deprotonation positions. However, the absorption of the chromophore in polar solution is substantially different for the distinct deprotonation locations. We also report on the time scales and pathways of relaxation after photoexcitation for the three photoactive yellow protein chromophore derivatives. As a result of these experiments, we could detect the phenoxide isomer within the deprotonated trans p-coumaric acid in gas phase; however, the occurrence of the carboxylate is uncertain. Several computational methods were used simultaneously to provide insights and assistance in the interpretation of our experimental results. The calculated excitation energies S(0)-S(1) are in good agreement with experiment for those systems having a negative charge on a phenoxide moiety. Although our augmented multiconfigurational quasidegenerate perturbation theory calculations agree with experiment in the description of the absorption spectrum of anions with a carboxylate functional group, there are some puzzling disagreements between experiment and some calculational methods in the description of these systems.

  5. Infrared absorption studies of the annealing of irradiated diamonds

    International Nuclear Information System (INIS)

    Woods, G.S.

    1984-01-01

    Natural (types Ia and IIa) and synthetic (type Ib) diamonds have been irradiated with energetic electrons and neutrons and then heated at temperatures up to 1400 deg C. Attendant changes in the infrared absorption spectra, especially above the Raman frequency (1332 cm -1 ), have been monitored. The most prominent absorption to develop in the infrared region proper, on annealing both type Ia and type Ib specimens, whether electron- or neutron-irradiated is the H1a line at 1450 cm -1 . Measurements taken of neutron-irradiated type Ia specimens show that the strength of this line is specimen-dependent, and that it is a linear function of radiation dose. Isochronal annealing studies show that the onset of the line occurs during heating at 250 deg C for type Ia specimens and at 650 deg C for type Ib specimens. The absorption begins to weaken during heating at 1100 deg C, but it is very persistent, surviving an anneal of 4 hours at 1400 deg C, albeit with diminished intensity. Three other weaker lines at 1438, 1358 and 1355 cm -1 develop with the 1450 cm -1 line, but differ from it and from each other in subsequent annealing behaviour. Other lines were observed; these are reported and discussed. (author)

  6. Studies on the radiation absorption characteristics of various rocks

    International Nuclear Information System (INIS)

    Rahman, K.N.; Abdullah, S.A.; Gazzaz, M.A.

    1984-05-01

    Radiation absorption characteristics of nine different rocks, namely, ferrugenous quartz, metabasalt, larvikite, coarse grained diorite, coarse grained granite, coarse grained alkali granite, marble, quartz mica schist, and metamorphosed rock are studied. The rocks were collected from Jeddah, Makkah, Mina and Taif areas. Special attention was given on the availability, compactness, physical formation and uniform composition in selecting the rocks. The rocks were identified by optical method and their elemental composition determined by chemical analysis. The data were used to calculate the effective atomic numbers, half value layers mass and linear attenuation coefficients. The half value layers and the linear attenuation coefficientsof these rocks were determined experimentally using Am-241, Cs-137,and Co-60 sources. The results are compared with those obtained by theoretical calculations and agrre within 10%. Most of the rocks show much higher radiation attenuation characteristics than the standard concrete. Rocks containing higher percentage of Fe, Ca, Ti, and Mn show much higher radiation absorption characteristics than concrete. Only granites are found to be almost equivalent to concrete. 12 Ref

  7. Absorption study of pentachlorophenol in persons working with wood preservatives

    Energy Technology Data Exchange (ETDEWEB)

    Jones, R.D.; Winter, D.P.; Cooper, A.J.

    1986-05-01

    Plasma and urinary pentachlorophenol (PCP) was measured in 209 workers who had occupational exposure to wood preservatives containing this compound and 101 workers not exposed occupationally to PCP. Workers were examined for chloracne and blood concentrations of bilirubin, gamma-glutamyltransferase (GGT), cholesterol and high-density lipoproteins (HDL) were determined. All the occupationally exposed groups showed evidence of PCP absorption; highest mean concentrations were found in remedial timber-treatment operatives (6.0 mmol/l for plasma and 274 nmol/mmol of creatinine for urine). Timber-yard workers also showed substantial evidence of absorption (mean plasma concentration 4.8 mmol/l). Persons formulating PCP-containing wood preservatives had the lowest concentrations of any exposed group sampled (mean plasma concentration 1.3 mmol/l, mean urinary concentration 39.6 nmol/mmol of creatinine). The occupational groups studied were not standardized for factors known to affect bilirubin, GGT, cholesterol and HDL. The inference that can be drawn from the results of these measurements is therefore limited. There was, however, no evidence of any disadvantageous effect of PCP on health as measured by these parameters. No overt case of chloracne was found.

  8. Remote controlled capsules in human drug absorption (HDA) studies.

    Science.gov (United States)

    Wilding, Ian R; Prior, David V

    2003-01-01

    The biopharmaceutical complexity of today's new drug candidates provides significant challenges for pharmaceutical scientists in terms of both candidate selection and optimizing subsequent development strategy. In addition, life cycle management of marketed drugs has become an important income stream for pharmaceutical companies, but the selection of least risk/highest benefit strategies is far from simple. The proactive adoption of human drug absorption (HDA) studies using remote controlled capsules offers the pharmaceutical scientist significant guidance for planning a route through the maze of product development. This review examines the position of HDA studies in drug development, using a variety of case histories and an insightful update on remote controlled capsules to achieve site-specific delivery.

  9. Theoretical experimental study of the factors that govern the molybdenum absorption signal by means of electro thermic atomic absorption spectroscopy

    International Nuclear Information System (INIS)

    Garaboto Farfan, M. A.

    1996-01-01

    The formation of molybdenum carbides in the atomizer, used in the electro thermic atomic absorption spectroscopy, is responsible for incomplete analyte removal in its analysis. This generates the apparition of the memory effect and little precision in the results. In this work, different variables that could affect the molybdenum absorption sign were investigated, as well as the influence of hydrochloric acid on the memory effect, by means of studies in the different stages: drying, calcination and atomization, and the samples deposition order in molybdenum solutions, either acidified or not acidified [es

  10. Picosecond transient absorption study of photodissociated carboxy hemoglobin and myoglobin

    International Nuclear Information System (INIS)

    Janes, S.M.; Dalickas, G.A.; Eaton, W.A.; Hochstrasser, R.M.

    1988-01-01

    The optical transient absorption spectra at 30 ps and 6.5 ns after photolysis are compared for both carboxy hemoglobin (HbCO) and carboxy myoglobin (MbCO). Both 355- and 532-nm excitation pulses were used. In all cases the shapes of the optical difference spectra thus generated are stationary over the complete time-scale studied. The photolysis spectra for MbCO are not significantly different from the equilibrium difference spectra generated on the same picosecond spectrometer when measured to an accuracy of +/- 0.5 nm. In addition, spectral parameters for delegated HbCO generated on the same spectrometer but detected by two different techniques, either by a Vidicon detector or point by point with photomultiplier tubes, are reported; the results are different from some of the previously reported picosecond experiments

  11. Studying energy absorption in tapered thick walled tubes

    Directory of Open Access Journals (Sweden)

    P. Hosseini Tehrani

    Full Text Available In many engineering structures different energy absorption systems may be used to improve crashworthiness capability of the system and to control damages that may occur in a system during an accident. Therefore, extensive research has been done on the energy-absorbing cells. In this paper, energy absorption in tapered thick walled tubes has been investigated. As a practical case, studies have been focused on the crush element of Siemens ER24PC locomotive. To investigate performance of this part at collision time, it has been modeled in Abaqus software and its collision characteristics have been evaluated. Considering that the crash element is folded at time of collision, an analytical approach has been presented for calculation of instantaneous folding force under axial load. Basis of this method is definition and analysis of main folding mechanism and calculation of average folding force. This method has been used for validation of the results of numerical solution. Since sheet thickness of the crash element is high and may be ruptured at time of collision, some damage models have been used for numerical simulations. One of the three damage models used in this paper is available in the software and coding has been done for two other damage models and desirable damage model has been specified by comparing results of numerical solution with results of laboratory test. In addition, authenticity of the desirable damage model has been studied through ECE R 66 standard. To improve crashworthiness characteristic some attempts, such as use of metal foam and creation of trigger in suitable situations to reduce maximum force resulting from collision, have been performed. Finally though different simulation optimal crush element has been introduced and its performance and efficiency have been evaluated.

  12. Infrared absorption spectroscopic study of Nd substituted Zn–Mg ...

    Indian Academy of Sciences (India)

    Unknown

    20, 0⋅40, 0⋅60, 0⋅80 and 1⋅00; y = 0⋅00, 0⋅05 and 0⋅10) ferrites were prepared by standard ceramic method and characterized by X-ray diffraction, scanning electron microscopy and infrared absorption spectroscopy. Far infrared absorption.

  13. Study of thermal treatments and irradiation on natural amethyst by optical absorption

    International Nuclear Information System (INIS)

    Dotto, C.T.

    1987-01-01

    Thermal treatment effects on the samples of amethyst from Minas Gerais and Rio Grande do Sul, through optical absorption measurements, are studied. The effects of cobalt 60 gama ray radiation on the amethyst from Minas Gerais through optical absorption measurements, are studied. The optical absorption spectra shows a basic line and bands in 10,500 cm -1 (k), in 18,300 cm -1 (θ) and in 28,000 cm -1 (ζ). The correlation between thermal treatment effects and radiation effects shows that the θ and ζ bands belongs to a same center and the k band to another center. The basic line vanishes by thermal treatments at 270 0 C. The analyses of the isothermal treatment decay and dose-curve reveal a complex kinetics, suggesting that the kinetic mechanisms involve the electron (s) and hole (s) migration in the lattice. The amethyst from Minas Gerais after being discolored at 470 0 C and irradiated again shows that the optical absorption bands don't recover the original absorbance, suggesting the existence of iron diffusion mechanisms in the lattice. After being isothermally annealed the amethyst from Rio Grande do Sul above 400 0 C temperature yield a yellow-brown color, probably due to the formation of Fe 2 O 3 precipitate. We suggest the this formation is due to iron diffusion and pre-existent oxygen vacancies. This model is reinforced through the observation the amethyst from Minas Gerais, isothermally treated at 470 0 C in highly reducing, also gets a yellow-brown color. (author) [pt

  14. Comparative study of five varieties of spodumene through optical absorption

    International Nuclear Information System (INIS)

    Fujii, A.T.; Isotani, S.

    1983-11-01

    A comparative study of five varieties of spodumene crystals from Brazil through optical absorption spectroscopy, classified according to the colours lylac, colourless I, colourless II, yellow and green is reported. This series shows a consistent increase of the [Fe]/[Mn] ratio. The principal bands in the yellow sample are at 7,000 and 9,000 cm -1 , and in the green sample besides these bands a band at 16,000 cm -1 is observed. In lylac, colourless I and colourless II samples, the principal bands are at 18,000 cm -1 and when irradiated two new bands appears at 15,700 cm -1 (E perpendicular to c) and 11,000 cm -1 (K perpendicular to c). It is suggested that in green and yellow samples the bands are due to Fe 2+ (at 7,000 cm -1 and 9,000 cm -1 ) and due to Fe 2+ - Fe 3+ charge transfer (at 16,000 cm -1 ). In lylac and colourless I samples the model for Mn 3+ at two different sites is applied. The colourless II corresponds to the case in which Mn 3+ is at one site alone, being prohibited from occupying the second site due to higher Fe concentration. (Author) [pt

  15. A Study of CO2 Absorption Using Jet Bubble Column

    Directory of Open Access Journals (Sweden)

    Setiadi Setiadi

    2010-10-01

    Full Text Available The phenomenon of plunging jet gas-liquid contact occurs quite often in nature, it's momentum carries small air bubbles with it into the reactor medium. The momentum of the liquid stream can be sufficient to carry small bubbles completely to the bottom of the vessel. A stream of liquid falling toward a level surface of that liquid will pull the surrounding air along with it. It will indent the surface of the liquid to form a trumpet-like shape. If the velocity of the stream is high enough, air bubbles will be pulled down, i.e. entrained into the liquid. This happens for two main reasons: air that is trapped between the edge of the falling stream and the trumpet-shaped surface profile and is carried below the surface. This study investigates the potential of a vertical liquid plunging jet for a pollutant contained gas absorption technique. The absorber consists of liquid jet and gas bubble dispersed phase. The effects of operating variables such as liquid flowrate, nozzle diameter, separator pressure, etc. on gas entrainment and holdup were investigated. The mass transfer of the system is governed by the hydrodynamics of the system. Therefore a clear and precise understanding of the above is necessary : to characterize liquid and gas flow within the system, 2. Variation in velocity of the jet with the use of different nozzle diameters and flow rates, 3. Relationship between the liquid and entrained airflow rate, 4. Gas entrainment rate and gas void fraction.

  16. Use of a standard meal to study iron absorption in humans

    International Nuclear Information System (INIS)

    Reddy, M.B.; Cook, J.D.

    1994-01-01

    Iron absorption varies widely between subjects and groups of subjects because of differences in iron status which markedly influence iron assimilation from the gastrointestinal tract. A small dose of isotopically labelled inorganic iron termed the reference dose (3 mg iron as FeSO 4 ) has been used extensively during the past two decades to standardize food iron absorption in human subjects and thereby eliminate the effect of differences in iron status. Recent studies from this laboratory have shown that because of the high variability of absorption from the reference dose, nonheme iron absorption from a standardized meal provides a more reliable means of standardizing absorption from regional diets. We therefore performed initial studies with a rice based meal but we found a relatively high variation in absorption from 2.0 to 4.7% that presumably reflects differences in the phytate content of rice fours. We then undertook the evaluation of meals prepared with farina, a wheat product that is available in most regions of the world. In six different studies from a farina based meal, iron absorption ranged from 3.4 to 6.5%. Nonheme iron absorption from the farina meal when evaluated in separate laboratories extensively engaged in human studies of iron absorption, ranged from 5.1 to 10.8% but when related to the FeSO 4 dose, a more consistent ratio between 0.21 to 0.26 was observed with the exception of one laboratory where a very low absorption of 1.1.% was observed. Percentage absorption from the farina based meal decreased when the iron content of the meal was increased and showed the expected facilitation of absorption when increasing amounts of ascorbic acid were added. By reducing variability and measuring iron absorption from food rather than inorganic iron, we believe that the use of this standard meal will facilitate comparison of iron absorption data obtained in laboratories throughout the world. 4 refs, 2 tabs

  17. Molecular basis of structural make-up of feeds in relation to nutrient absorption in ruminants, revealed with advanced molecular spectroscopy: A review on techniques and models

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, Md. Mostafizar [Department of Animal and Poultry Science, University of Saskatchewan, Saskatoon, Saskatchewan, Canada; Yu, Peiqiang [Department of Animal and Poultry Science, University of Saskatchewan, Saskatoon, Saskatchewan, Canada

    2017-01-31

    Progress in ruminant feed research is no more feasible only based on wet chemical analysis, which is merely able to provide information on chemical composition of feeds regardless of their digestive features and nutritive value in ruminants. Studying internal structural make-up of functional groups/feed nutrients is often vital for understanding the digestive behaviors and nutritive values of feeds in ruminant because the intrinsic structure of feed nutrients is more related to its overall absorption. In this article, the detail information on the recent developments in molecular spectroscopic techniques to reveal microstructural information of feed nutrients and the use of nutrition models in regards to ruminant feed research was reviewed. The emphasis of this review was on (1) the technological progress in the use of molecular spectroscopic techniques in ruminant feed research; (2) revealing spectral analysis of functional groups of biomolecules/feed nutrients; (3) the use of advanced nutrition models for better prediction of nutrient availability in ruminant systems; and (4) the application of these molecular techniques and combination of nutrient models in cereals, co-products and pulse crop research. The information described in this article will promote better insight in the progress of research on molecular structural make-up of feed nutrients in ruminants.

  18. Poster 7: Could PAH or HAC explain the Titan's stratosphere absorption around 3.4 µm revealed by solar occultations?

    Science.gov (United States)

    Cordier, Daniel; Cours, Thibaud; Rey, Michael; Maltagliati, Luca; Seignovert, Benoit; Biennier, Ludovic

    2016-06-01

    In 2006, during Cassini's 10th flyby of Titan (T10), Bellucci et al. (2009) observed a solar occultation by Titan's atmosphere through the solar port of the Cassini/VIMS instrument. These authors noticed the existence of an unexplained additional absorption superimposed to the CH4 3.3 µm band. Because they were unable to model this absorption with gases, they attributed this intriguing feature to the signature of solid state organic components. Kim et al. (2011) revisited the data collected by Bellucci et al. (2009) and they considered the possible contribution of aerosols formed by hydrocarbon ices. They specifically took into account C2H6, CH4, CH3CN, C5H12 and C6H12 ices. More recently, Maltagliati et al. (2015) analyzed a set of four VIMS solar occultations, corresponding to flybys performed between January 2006 and September 2011 at different latitudes. They confirmed the presence of the 3.3 µm absorption in all occultations and underlined the possible importance of gaseous ethane, which has a strong plateau of absorption lines in that wavelength range.In this work, we show that neither hydrocarbon ices nor molecular C2H6 cannot satisfactorily explain the observed absorption. Our simulations speak in favor of an absorption due to the presence of PAH molecules or HAC in the stratosphere of Titan. PAH have been already considered by Lopes-Puertas et al. (2013) at altitudes larger than ˜900 km and tentatively identified in the stratosphere by Maltagliati et al. (2015); PAH and HAC are good candidates for Titan's aerosols precursors.

  19. Zinc absorption study using an enriched stable isotope (70Zn)

    International Nuclear Information System (INIS)

    Li Gongpan.

    1990-04-01

    A weaning food from fermented soybean was prepared for increasing the bioavailability of zinc. The zinc absorption was compared with that of a weaning food from non-fermented soybean and normal staple food. A stable isotope tracer technique ( 70 Zn) and neutron activation were used for determining the absorption of zinc. Nine children aged 7 to 18 months were tested. Zinc bioavailability of weaning food from fermented soybean is higher than that of normal weaning food. The weight increment and zinc nutrition of children having weaning food from fermented soybean are improved by this diet. 5 tabs

  20. Ultrafast photo-initiated molecular quantum dynamics in the DNA dinucleotide d(ApG) revealed by broadband transient absorption spectroscopy.

    Science.gov (United States)

    Stuhldreier, Mayra C; Temps, Friedrich

    2013-01-01

    The ultrafast photo-initiated quantum dynamics of the adenine-guanine dinucleotide d(ApG) in aqueous solution (pH 7) has been studied by femtosecond time-resolved spectroscopy after excitation at lambda = 260 nm. The results reveal a hierarchy of processes on time scales from tau 100 ps. Characteristic spectro-temporal signatures are observed indicating the transformation of the molecules in the electronic relaxation from the photo-excited state to a long-lived exciplex. In particular, broadband UV/VIS excited-state absorption (ESA) measurements detected a distinctive absorption by the excited dinucleotide around lambda = 335 nm, approximately 0.5 eV to the blue compared to the maximum of the broad and unstructured ESA spectrum after excitation of an equimolar mixture of the mononucleotides dAMP and dGMP. A similar feature has been identified as signature of the excimer in the dynamics of the adenine dinucleotide d(ApA). The lifetime of the d(ApG) exciplex was found to be tau = 124 +/- 4 ps both from the ESA decay time and from the ground-state recovery time, far longer than the sub-picosecond lifetimes of excited dAMP or dGMP. Fluorescence-time profiles measured by the up-conversion technique indicate that the exciplex state is reached around approximately 6 ps after excitation. Very weak residual fluorescence at longer times red-shifted to the emission from the photo-excited state shows that the exciplex is almost optically dark, but still has enough oscillator strength to give rise to the dual fluorescence of the dinucleotide in the static fluorescence spectrum.

  1. A novel multiplex absorption spectrometer for time-resolved studies

    Science.gov (United States)

    Lewis, Thomas; Heard, Dwayne E.; Blitz, Mark A.

    2018-02-01

    A Time-Resolved Ultraviolet/Visible (UV/Vis) Absorption Spectrometer (TRUVAS) has been developed that can simultaneously monitor absorption at all wavelengths between 200 and 800 nm with millisecond time resolution. A pulsed photolysis laser (KrF 248 nm) is used to initiate chemical reactions that create the target species. The absorption signals from these species evolve as the composition of the gas in the photolysis region changes over time. The instrument can operate at pressures over the range ˜10-800 Torr and can measure time-resolved absorbances systems (in particular the Herriott cell), there are fundamental differences, most notably the ability to adjust each mirror to maximise the overlap between the probe beam and the photolysis laser. Another feature which aids the sensitivity and versatility of the system is the use of 2 high-throughput spectrographs coupled with sensitive line-array CCDs, which can measure absorbance from ˜200 to 800 nm simultaneously. The capability of the instrument is demonstrated via measurements of the absorption spectrum of the peroxy radical, HOCH2CH2O2, and its self-reaction kinetics.

  2. Microwave absorption studies of MgB2 superconductor

    Indian Academy of Sciences (India)

    band (9–. 10 GHz) spectrometer. Both polycrystalline pellet and single-grain MgB2, having nearly the same Tc (∼ 39 K) and same size (3×2×1 mm3), were used in the present investigations. Low field modulated microwave absorption signals ...

  3. Photo absorption studies of polyatomic molecules using Indus 1 synchrotron radiation source

    International Nuclear Information System (INIS)

    Saraswathy, P.; Sunanda, K.; Aparna, S.; Rajashekar, B.N.; Das, N.C.

    2004-06-01

    The Photophysics beamline is a medium resolution beamline designed for carrying out photo absorption and fluorescence experiments using the synchrotron radiation source Indus-l. This beamline has been commissioned recently and is in operation. An experimental setup for gas phase absorption studies has been developed and installed. Absorption spectra of a few polyatomicmolecules viz. benzene, ammonia, carbon disulphide and acetone were recorded in the wavelength region 1500 -3000 A. The results from this study indicated the satisfactory performance of the beam line as well as the experimental setup. Details of the first set of absorption experiments carried out are discussed in this report. (author)

  4. Non-destructive studies of fuel pellets by neutron resonance absorption radiography and thermal neutron radiography

    Energy Technology Data Exchange (ETDEWEB)

    Tremsin, A.S., E-mail: ast@ssl.berkeley.edu [University of California, Berkeley, CA 94720 (United States); Vogel, S.C.; Mocko, M.; Bourke, M.A.M.; Yuan, V.; Nelson, R.O.; Brown, D.W. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Feller, W.B. [NOVA Scientific, Inc., 10 Picker Rd., Sturbridge, MA 01566 (United States)

    2013-09-15

    Many isotopes in nuclear materials exhibit strong peaks in neutron absorption cross sections in the epithermal energy range (1–1000 eV). These peaks (often referred to as resonances) occur at energies specific to particular isotopes, providing a means of isotope identification and concentration measurements. The high penetration of epithermal neutrons through most materials is very useful for studies where samples consist of heavy-Z elements opaque to X-rays and sometimes to thermal neutrons as well. The characterization of nuclear fuel elements in their cladding can benefit from the development of high resolution neutron resonance absorption imaging (NRAI), enabled by recently developed spatially-resolved neutron time-of-flight detectors. In this technique the neutron transmission of the sample is measured as a function of spatial location and of neutron energy. In the region of the spectra that borders the resonance energy for a particular isotope, the reduction in transmission can be used to acquire an image revealing the 2-dimensional distribution of that isotope within the sample. Provided that the energy of each transmitted neutron is measured by the neutron detector used and the irradiated sample possesses neutron absorption resonances, then isotope-specific location maps can be acquired simultaneously for several isotopes. This can be done even in the case where samples are opaque or have very similar transmission for thermal neutrons and X-rays or where only low concentrations of particular isotopes are present (<0.1 atom% in some cases). Ultimately, such radiographs of isotope location can be utilized to measure isotope concentration, and can even be combined to produce three-dimensional distributions using tomographic methods. In this paper we present the proof-of-principle of NRAI and transmission Bragg edge imaging performed at Flight Path 5 (FP5) at the LANSCE pulsed, moderated neutron source of Los Alamos National Laboratory. A set of urania mockup

  5. Continued studies of the gastrointestinal absorption of plutonium by rodents

    International Nuclear Information System (INIS)

    Larsen, R.P.; Bhattacharyya, M.H.; Oldham, R.D.; Moretti, E.S.; Spaletto, M.I.

    1982-01-01

    In the mouse the gastrointestinal absorption of hexavalent plutonium (the form present in chlorinated drinking water) is (1) a factor of about ten lower in the fed animal than in the fasted one (0.015 vs 0.15%), (2) independent of plutonium concentration over a range that broadly brackets the MPC for plutonium in drinking water, and (3) independent of the time of day the solution is administered to fasted animals. Other factors related to the determination of G.I. absorption which have been investigated are: (1) the adsorption of plutonium onto teeth of animals during both gavage and ad libitum administrations, (2) the formation of polymeric tetravalent plutonium during and subsequent to solution preparation, and (3) the relationship between the metabolic behavior of plutonium solutions, administered both intragastrically and intravenously, and their ultrafilterability

  6. Study on hydrogen absorption/desorption properties of uranium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Hiroshi; Yamaguchi, Kenji; Yamawaki, Michio [Tokyo Univ., Tokai, Ibaraki (Japan). Nuclear Engineering Research Lab.

    1996-10-01

    Hydrogen absorption/desorption properties of two U-Mn intermetallic compounds, U{sub 6}Mn and UMn{sub 2}, were investigated. U{sub 6}Mn absorbed hydrogen and the hydrogen desorption pressure of U{sub 6}Mn obtained from this experiment was higher than that of U, which was considered to be the effect of alloying, whereas UMn{sub 2} was not observed to absorb hydrogen up to 50 atm at room temperature. (author)

  7. Optical absorption and electron spin resonance studies of Cu in ...

    Indian Academy of Sciences (India)

    Unknown

    Na2O–50B2O3–10As2O3 glasses. In this paper, we report the ESR and optical absorption spectra of Cu2+ ions in xLi2O–(40 – x)Na2O–50B2O3–. 10As2O3 glasses. The values of x were adjusted so that the compositional parameter defined as ...

  8. Studies on the red absorption band of chlorophyll a in vivo

    NARCIS (Netherlands)

    Thomas, J.B.; Kleinen Hammans, J.W.; Arnolds, W.J.

    1965-01-01

    It was studied whether certain earlier observed weak shoulders on the red absorption band of chlorophyll a in vivo might represent anomalies due to overlap of absorption bands. The results are suggested of the fact that no such anomalies occur. It is therefore concluded that the present study

  9. Studies on the absorption and excretion of arsenic in test animals

    International Nuclear Information System (INIS)

    Mikulski, J.; Walczak, Z.; Politowski, M.

    1980-01-01

    The partition of arsenous compounds in cats between blood, lymph and urine has been studied by the isotopic method. The rate of poison absorption from the intestinal tract and poison excretion with urine have also been investigated. It was found that arsenic is evenly distributed between blood and lymph, but its concentration in urine is about 100 times larger. The rate of arsenic absorption is very high - the absorption time is of the order of minutes and the absorption is shortly followed by the appearance of arsenic in urine. (author)

  10. Determination of the separation between the soft X-ray K-emission and K-absorption edges in beryllium metal from self-absorption studies

    International Nuclear Information System (INIS)

    Crisp, R.S.

    1979-01-01

    Recent theoretical studies have aroused interest in the phonon broadening of the soft X-ray emission and absorption edges and the shift between them. Using a self-absorption technique a separation of about 0.2 eV is shown to exist between the edges in Be metal. This shift explains the very small self-absorption effects previously observed in Be by Crisp (1977). (Auth.)

  11. Determination of the separation between the soft X-ray K-emission and K-absorption edges in beryllium metal from self-absorption studies

    International Nuclear Information System (INIS)

    Crisp, R.S.

    1979-01-01

    Recent theoretical studies have aroused interest in the phonon broadening of the soft X-ray emission and absorption edges and the shift between them. Using a self-absorption technique a separation of about 0.2 eV is shown to exist between the edges in Be metal. This shift explains the very small self-absorption effects previously observed in Be. (Auth.)

  12. Synthesis, XRD, TEM, EPR, and Optical Absorption Spectral Studies of CuZnO2 Nanocompound

    Directory of Open Access Journals (Sweden)

    T. Ravindra Reddy

    2014-01-01

    Full Text Available Synthesis of nano CuZnO2 compound is carried out by thermal decomposition method. The crystalline phase of the material is characterized by XRD. The calculated unit cell constants are a=3.1 Å and c=3.4786 Å and are of tetragonal structure. The unit cell constants are different from wurtzite (hexagonal which indicate that a nanocompound is formed. Further TEM images reveal that the metal ion is in tetragonal structure with oxygen ligands. The prepared CuZnO2 is then characterized for crystallite size analysis by employing transmission electron microscopy (TEM. The size is found to be 100 nm. Uniform bright rings are noticed in the TEM picture suggesting that the nanocrystals have preferential instead of random orientations. The selected-area electron diffraction (SAED pattern clearly indicates the formation of CuO-ZnO nanocompound. The nature of bonding is studied by electron paramagnetic resonance (EPR. The covalency character is about 0.74 and thus the compound is electrically less conductive. Optical absorption spectral studies suggest that Cu(II is placed in tetragonal elongation crystal field. The spin-orbit coupling constant, λ, is calculated using the EPR and optical absorption spectral results suggest some covalent bond between metal and ligand. Near infrared (NIR spectra are due to hydroxyl and water fundamentals.

  13. Does the Size Matter for Dynamics Capabilities? A Study on Absorptive Capacity

    Directory of Open Access Journals (Sweden)

    Marlon Fernandes Rodrigues Alves

    2016-10-01

    Full Text Available The objective of this study is to understand how organizational size influences dynamic capabilities in Brazil. To arrive at this understanding, structural equation modeling analysis was performed using the Brazilian Innovation Survey (PINTEC database to test for differences between SMEs and large companies in respect to the relationship between absorptive capacity (AC dimensions and innovation performance. The results show that in large companies, Potential AC and Realized AC impact innovation performance, whereas in small and medium-sized enterprises (SMEs, only Realized AC has an influence. In addition, SMEs are, in fact, better at converting Realized AC into innovation performance than large companies, probably due to their flexibility and agility. These findings reveal that organizational sizes influence the impact of dynamic capabilities on performance.

  14. Ionization yield and absorption spectra reveal superexcited Rydberg state relaxation processes in H{sub 2}O and D{sub 2}O

    Energy Technology Data Exchange (ETDEWEB)

    Fillion, J-H [LERMA, CNRS-UMR 8112, Observatoire de Paris-Meudon, 5 place J Janssen, F-92195, Meudon (France); Dulieu, F [LERMA, CNRS-UMR 8112, Observatoire de Paris-Meudon, 5 place J Janssen, F-92195, Meudon (France); Baouche, S [LERMA, CNRS-UMR 8112, Observatoire de Paris-Meudon, 5 place J Janssen, F-92195, Meudon (France); Lemaire, J-L [LERMA, CNRS-UMR 8112, Observatoire de Paris-Meudon, 5 place J Janssen, F-92195, Meudon (France); Jochims, H W [Institut fuer Physikalische und Theoretische Chemie der Freien Universitaet Berlin, Takustrasse 3, D-14195 Berlin 33 (Germany); Leach, S [LERMA, CNRS-UMR 8112, Observatoire de Paris-Meudon, 5 place J Janssen, F-92195, Meudon (France)

    2003-07-14

    The absorption cross section and the ionization quantum yield of H{sub 2}O have been measured using a synchrotron radiation source between 9 and 22 eV. Comparison between the two curves highlights competition between relaxation processes for Rydberg states converging to the first A-tilde {sup 2}A{sub 1} and to the second B-tilde {sup 2}B{sub 2} excited states of H{sub 2}O{sup +}. Comparison with D{sub 2}O absorption and ionization yields, derived from Katayama et al (1973 J. Chem. Phys. 59 4309), reveals specific energy-dependent deuteration effects on competitive predissociation and autoionization relaxation channels. Direct ionization was found to be only slightly affected by deuteration.

  15. Experimental Challenges in Studying Hydrogen Absorption in Ultrasmall Metal Nanoparticles

    International Nuclear Information System (INIS)

    Zlotea, Claudia; Oumellal, Yassine; Provost, Karine; Ghimbeu, Camelia Matei

    2016-01-01

    Recent advances on synthesis, characterization, and hydrogen absorption properties of ultrasmall metal nanoparticles (defined here as objects with average size ≤3 nm) are briefly reviewed in the first part of this work. The experimental challenges encountered in performing accurate measurements of hydrogen absorption in Mg- and noble metal-based ultrasmall nanoparticles are addressed. The second part of this work reports original results obtained for ultrasmall bulk-immiscible Pd–Rh nanoparticles. Carbon-supported Pd–Rh nanoalloys in the whole binary chemical composition range have been successfully prepared by liquid impregnation method followed by reduction at 300°C. EXAFS investigations suggested that the local structure of these nanoalloys is partially segregated into Rh-rich core and Pd-rich surface coexisting within the same nanoparticles. Downsizing to ultrasmall dimensions completely suppresses the hydride formation in Pd-rich nanoalloys at ambient conditions, contrary to bulk and larger nanosized (5–6 nm) counterparts. The ultrasmall Pd 90 Rh 10 nanoalloy can absorb hydrogen-forming solid solutions under these conditions, as suggested by in situ X-ray diffraction (XRD). Apart from this composition, common laboratory techniques, such as in situ XRD, DSC, and PCI, failed to clarify the hydrogen interaction mechanism: either adsorption on developed surfaces or both adsorption and absorption with formation of solid solutions. Concluding insights were brought by in situ EXAFS experiments at synchrotron: ultrasmall Pd 75 Rh 25 and Pd 50 Rh 50 nanoalloys absorb hydrogen-forming solid solutions at ambient conditions. Moreover, the hydrogen solubility in these solid solutions is higher with increasing Pd content, and this trend can be understood in terms of hydrogen preferential occupation in the Pd-rich regions, as suggested by in situ EXAFS. The Rh-rich nanoalloys (Pd 25 Rh 75 and Pd 10 Rh 90 ) only adsorb hydrogen on the developed surface of ultrasmall

  16. X-ray absorption and emission studies of diamond nanoparticles

    International Nuclear Information System (INIS)

    Van Buuren, T.; Willey, T.; Raty, J.Y.; Galli, G.; Terminello, L.J.; Bostedt, C.

    2004-01-01

    Full text: A new family of carbon nanopaticles produced in detonations, are found to have a core of diamond with a coating fullerene- like carbon. X-ray diffraction and TEM show that the nanodiamond powder is crystalline and approximately 4 nm in diameter. These nano-sized diamonds do not display the characteristic property of other group IV nanoparticles: a strong widening of the energy gap between the conduction and valence bands owing to quantum-confinement effects. For nano-sized diamond with a size distribution of 4 nm, there is no shift of the band energies relative to bulk diamond. Although the C1s core exciton feature clearly observed in the K-edge absorption edge of bulk diamond is shifted and broadening due to increased overlap of the excited electron with the core holein the small particle. Also the depth of the second gap in the nanodiamond spectra is shallower than that of bulk diamond. A feature at lower energy in the X-ray absorption spectra that is not present in the bulk samples is consistent with a fullerene like surface reconstruction. By exposing the diamond nanoparticles to an Argon /Oxygen plasma then annealing in a UHV environment we have obtained a hydrogen free surface. The nanodiamonds processed in this manner show an increase fullerene type contribution in the carbon x-ray absorption pre-edge. High spatial resolution EELS measurements of the empty states of a single nanodiamond particle acquired with a ld emission TEM also show the core of the particle is bulk diamond like where as the surface has a fullerene like structure. Standard density-functional calculations on clusters in which the diamond surface bonds are terminated with hydrogen atoms, show that the bandgap begins to increase above the bulk value only for clusters smaller than 1 nm. Surface hydrogen atoms are found to be about as close as they do in molecular hydrogen and can escape as H 2 , forcing the respective carbon atoms to rearrange. A series of such rearrangements can

  17. Beta-decay of 103In studied by using a total absorption spectrometer

    International Nuclear Information System (INIS)

    Karny, M.; Batist, L.; Moroz, F.; Wittmann, V.; Brown, B. A.; Cano-Ott, D.; Gadea, A.; Rubio, B.; Tain, J. L.; Collatz, R.; Guglielmetti, A.; Hellstroem, M.; Hu, Z.; Kirchner, R.; Roeckl, E.; Shibata, M.; Grzywacz, R.; Janas, Z.; Plochocki, A.; Szerypo, J.

    1998-01-01

    The β decay of the neutron-deficient isotope 103 In was investigated by using total absorption γ-ray spectrometry on mass-separated sources. The measurement reveals a high-lying resonance of the β-decay strength in striking disagreement with high-resolution γ-ray data. The result is discussed in comparison with shell-model predictions

  18. STUDY ON EUROPEAN FUNDS ABSORPTION IN ROMANIA FOR MEASURE 313

    Directory of Open Access Journals (Sweden)

    Florentina D. MATEI

    2014-06-01

    Full Text Available In this paper we wish to highlight the main causes of regional disparities in Romania in terms of absorption of European funds through Measure 313: Encouragement of tourism activities. The post-accession of Romania shows a major deficiency in attracting funds from the European Union, this situation is generated, in particular, by the lack of a coherent long-term vision of the authorities, insufficient resources for co-financing projects, low administrative capacity at central and local level, lack of inter-institutional coordination, public-private partnerships failures and insufficient skilled human resources . We will analyze the number of projects approved and implemented in each region of Romania (2007-2013 to establish the real possibilities of expansion of rural tourism.

  19. Strong crystal field effect in ? - optical absorption study

    Science.gov (United States)

    Gajek, Z.; Krupa, J. C.

    1998-12-01

    =-1 Results of optical absorption measurements in polarized light on tetravalent neptunium diluted in a 0953-8984/10/50/021/img6 single crystal are reported. The recorded spectra are complex, pointing to the presence of an 0953-8984/10/50/021/img7 impurity. The electronic transitions assigned to the 0953-8984/10/50/021/img8 ion are interpreted in terms of the usual model, following the actual understanding of the neptunium electronic structure and independent theoretical predictions. R.m.s. deviations of the order of 0953-8984/10/50/021/img9 have been obtained for 42 levels fitted with 11 free parameters. The crystal field effect resulting from the fitting is considerably larger than that observed for the uranium ion in the same host.

  20. Photoisomerization of ethyl ferulate: A solution phase transient absorption study

    Science.gov (United States)

    Horbury, Michael D.; Baker, Lewis A.; Rodrigues, Natércia D. N.; Quan, Wen-Dong; Stavros, Vasilios G.

    2017-04-01

    Ethyl ferulate (ethyl 4-hydroxy-3-methoxycinnamate) is currently used as a sunscreening agent in commercial sunscreen blends. Recent time-resolved gas-phase measurements have demonstrated that it possesses long-lived (>ns) electronic excited states, counterintuitive to what one might anticipate for an effective sunscreening agent. In the present work, the photodynamics of ethyl ferulate in cyclohexane, are explored using time-resolved transient electronic absorption spectroscopy, upon photoexcitation to the 11ππ∗ and 21ππ∗ states. We demonstrate that ethyl ferulate undergoes efficient non-radiative decay to repopulate the electronic ground state, mediated by trans-cis isomerization. These results strongly suggest that even mild perturbations induced by a non-polar solvent, as may be found in a closer-to-market sunscreen blend, may contribute to our understanding of ethyl ferulate's role as a sunscreening agent.

  1. Ultrafast Carrier Trapping of a Metal-Doped Titanium Dioxide Semiconductor Revealed by Femtosecond Transient Absorption Spectroscopy

    KAUST Repository

    Sun, Jingya; Yang, Yang; Khan, Jafar I.; Alarousu, Erkki; Guo, Zaibing; Zhang, Xixiang; Zhang, Qiang; Mohammed, Omar F.

    2014-01-01

    We explored for the first time the ultrafast carrier trapping of a metal-doped titanium dioxide (TiO2) semiconductor using broad-band transient absorption (TA) spectroscopy with 120 fs temporal resolution. Titanium dioxide was successfully doped layer-by-layer with two metal ions, namely tungsten and cobalt. The time-resolved data demonstrate clearly that the carrier trapping time decreases progressively as the doping concentration increases. A global-fitting procedure for the carrier trapping suggests the appearance of two time components: a fast one that is directly associated with carrier trapping to the defect state in the vicinity of the conduction band and a slow one that is attributed to carrier trapping to the deep-level state from the conduction band. With a relatively long doping deposition time on the order of 30 s, a carrier lifetime of about 1 ps is obtained. To confirm that the measured ultrafast carrier dynamics are associated with electron trapping by metal doping, we explored the carrier dynamics of undoped TiO2. The findings reported here may be useful for the implementation of high-speed optoelectronic applications and fast switching devices.

  2. Ultrafast Carrier Trapping of a Metal-Doped Titanium Dioxide Semiconductor Revealed by Femtosecond Transient Absorption Spectroscopy

    KAUST Repository

    Sun, Jingya

    2014-06-11

    We explored for the first time the ultrafast carrier trapping of a metal-doped titanium dioxide (TiO2) semiconductor using broad-band transient absorption (TA) spectroscopy with 120 fs temporal resolution. Titanium dioxide was successfully doped layer-by-layer with two metal ions, namely tungsten and cobalt. The time-resolved data demonstrate clearly that the carrier trapping time decreases progressively as the doping concentration increases. A global-fitting procedure for the carrier trapping suggests the appearance of two time components: a fast one that is directly associated with carrier trapping to the defect state in the vicinity of the conduction band and a slow one that is attributed to carrier trapping to the deep-level state from the conduction band. With a relatively long doping deposition time on the order of 30 s, a carrier lifetime of about 1 ps is obtained. To confirm that the measured ultrafast carrier dynamics are associated with electron trapping by metal doping, we explored the carrier dynamics of undoped TiO2. The findings reported here may be useful for the implementation of high-speed optoelectronic applications and fast switching devices.

  3. Studies on amino acid absorption and protein metabolism in the rat following total gastrectomy

    International Nuclear Information System (INIS)

    Walter, F.; Czarnetzki, H.D.; Albert, H.; Schwokowski, C.; Junghans, P.; Jung, K.; Akademie der Wissenschaften der DDR, Leipzig. Zentralinstitut fuer Isotopen- und Strahlenforschung)

    1982-01-01

    Rats were gastrectomized according to Graham and Longmire/Guetgemann, resp. 6 to 12 weeks after gastrectomy the animals received a single dose of 15 N-glycine with the food. 15 N excretion has been determined every 12 hours for 5 days. All rats revealed a positive N balance. Urinary excretion of 15 N was significantly less in rats operated according to Graham (missing duodenal passage) than in the controls and those operated according to Longmire. The differences seem to be caused by differently fast absorption, but the disturbances in the amino acid absorption are not aggravating and N balance and protein synthesis are normal

  4. X-ray absorption fine structure (XAFS) spectroscopy: a tool for structural studies in material sciences (abstract)

    International Nuclear Information System (INIS)

    Akhtar, M.J.

    2011-01-01

    XAFS spectroscopy has revealed itself as a powerful technique for structural characterization of the local atomic environment of individual atomic species, including bond distances, coordination numbers and type of nearest neighbors surrounding the central atom. This technique is particularly useful for materials that show considerable structural and chemical disorder. XAFS spectroscopy has found extensive applications in determining the local atomic and electronic structure of the absorbing centers (atoms) in the materials science, physics, chemistry, biology and geophysics. X-ray absorption edges contain a variety of information on the chemical state and the local structure of the absorbing atom. On the higher energy side of an absorption edge fine structure is observed due to backscattering of the emitted photoelectron. The post-edge region can be divided into two parts. The X-ray Absorption Near Edge Structure (XANES) which extends up to 50 eV of an absorption edge, the spectrum is interpreted in terms of the appropriate components of the local density of states, which would be expected to be sensitive to the valence state of the atom. The intensity, shape and location of the absorption edge features provide information on the valence state, electronic structure and coordination geometry of the absorbing atom.The Extended X-ray Absorption Fine Structure (EXAFS) region is dominated by the single scattering processes and extends up to 1000 eV above the edge and provides information on the radial distribution (coordination number, radial distance and type of neighboring atoms) around the central atom. The results on perovskite based and spinel ferrites systems will be presented, where valence state and cation distributions are determined; the present study will show focus on SrFeO/sub 3/, MnFe/sub 2/O/sub 4/ and Zn/sub 1-x/Ni/sub x/Fe/sub 2/O/sub 4/ materials. (author)

  5. Deuterium absorption in Mg70Al30 thin films with bilayer catalysts: A comparative neutron reflectometry study

    International Nuclear Information System (INIS)

    Poirier, Eric; Harrower, Chris T.; Kalisvaart, Peter; Bird, Adam; Teichert, Anke; Wallacher, Dirk; Grimm, Nico; Steitz, Roland; Mitlin, David; Fritzsche, Helmut

    2011-01-01

    Highlights: → Mg 70 Al 30 thin films studied for hydrogen absorption using in situ neutron reflectometry. → Films with Ta/Pd, Ti/Pd and Ni/Pd bilayer catalysts systematically compared. → Measurements reveals deuterium spillover from the catalysts to the MgAl phase. → The use of Ti-Pd bilayer offers best results in terms of amount absorbed and kinetics. → Key results cross-checked with X-ray reflectometry. - Abstract: We present a neutron reflectometry study of deuterium absorption in thin films of Al-containing Mg alloys capped with a Ta/Pd, Ni/Pd and Ti/Pd-catalyst bilayer. The measurements were performed at room temperature over the 0-1 bar pressure range under quasi-equilibrium conditions. The modeling of the measurements provided a nanoscale representation of the deuterium profile in the layers at different stages of the absorption process. The absorption mechanism observed was found to involve spillover of atomic deuterium from the catalyst layer to the Mg alloy phase, followed by the deuteration of the Mg alloy. Complete deuteration of the Mg alloy occurs in a pressure range between 100 and 500 mbar, dependent on the type of bilayer catalyst. The use of a Ti/Pd bilayer catalyst yielded the best results in terms of both storage density and kinetic properties.

  6. Preparation, characterization and nonlinear absorption studies of cuprous oxide nanoclusters, micro-cubes and micro-particles

    Science.gov (United States)

    Sekhar, H.; Narayana Rao, D.

    2012-07-01

    Cuprous oxide nanoclusters, micro-cubes and micro-particles were successfully synthesized by reducing copper(II) salt with ascorbic acid in the presence of sodium hydroxide via a co-precipitation method. The X-ray diffraction and FTIR studies revealed that the formation of pure single-phase cubic. Raman and EPR spectral studies show the presence of CuO in as-synthesized powders of Cu2O. Transmission electron microscopy and field emission scanning electron microscopy data revealed that the morphology evolves from nanoclusters to micro-cubes and micro-particles by increasing the concentration of NaOH. Linear optical measurements show absorption peak maximum shifts towards red with changing morphology from nanoclusters to micro-cubes and micro-particles. The nonlinear optical properties were studied using open aperture Z-scan technique with 532 nm 6 ns laser pulses. Samples-exhibited both saturable as well as reverse saturable absorption. Due to confinement effects (enhanced band gap), we observed enhanced nonlinear absorption coefficient (β) in the case of nanoclusters compared to their micro-cubes and micro-particles.

  7. Nustar Reveals an Intrinsically X-ray Weak Broad Absorption Line Quasar in the Ultraluminous Infrared Galaxy Markarian 231

    Science.gov (United States)

    Teng, Stacy H.; Brandt. W. N.; Harrison, F. A.; Luo, B.; Alexander, D. M.; Bauer, F. E.; Boggs, S. E.; Christensen, F. E.; Comastri, A.; Craig, W. W.; hide

    2014-01-01

    We present high-energy (3-30 keV) NuSTAR observations of the nearest quasar, the ultraluminous infrared galaxy (ULIRG) Markarian 231 (Mrk 231), supplemented with new and simultaneous low-energy (0.5-8 keV) data from Chandra. The source was detected, though at much fainter levels than previously reported, likely due to contamination in the large apertures of previous non-focusing hard X-ray telescopes. The full band (0.5-30 keV) X-ray spectrum suggests the active galactic nucleus (AGN) in Mrk 231 is absorbed by a patchy and Compton-thin N(sub H) approx. 1.2(sup +0.3) sub-0.3) x 10(exp 23) / sq cm) column. The intrinsic X-ray luminosity L(sub 0.5-30 Kev) approx. 1.0 x 10(exp 43) erg /s) is extremely weak relative to the bolometric luminosity where the 2-10 keV to bolometric luminosity ratio is approx. 0.03% compared to the typical values of 2-15%. Additionally, Mrk 231 has a low X-ray-to-optical power law slope alpha(sub 0X) approx. -1.7. It is a local example of a low-ionization broad absorption line (LoBAL) quasar that is intrinsically X-ray weak. The weak ionizing continuum may explain the lack of mid-infrared [O IV], [Ne V], and [Ne VI] fine-structure emission lines which are present in sources with otherwise similar AGN properties. We argue that the intrinsic X-ray weakness may be a result of the super-Eddington accretion occurring in the nucleus of this ULIRG, and may also be naturally related to the powerful wind event seen in Mrk 231, a merger remnant escaping from its dusty cocoon.

  8. A VISION OF ORKUT´S USERS: STUDYING THIS PHENOMENON THROUGH COGNITIVE ABSORPTION

    OpenAIRE

    Mauri Leodir Löbler; Monize Sâmara Visentini; Vania de Fátima Barros Estivalete

    2011-01-01

    This study aims to identify the influence that Cognitive Absorption has on the intention of using Orkut. It happens due to the fact that Cognitive Absorption is related to the state of deep involvement users carry with an individual task, performed with the support of Information Technology (IT); it corroborates the study on this virtual community. Therefore, through descriptive research with a quantitative character and with the aid of structural equations, 645 Orkut users were investigated....

  9. Structural studies using X-ray absorption and scattering techniques

    International Nuclear Information System (INIS)

    Ericson, Agneta.

    1989-01-01

    The thesis presents extended X-ray absorption fine structure, EXAFS, and large angle X-ray scattering, LAXS, techniques; instrumentation, data collection and reduction, and applications. These techniques have been used to determine the structures of magnesium halides and organomagnesium halides in diethyl ether and tetrahydrofuran solution. The iodides were used for the LAXS measurements and Br K edge EXAFS data were collected for the corresponding bromides. Two different complexes are present in the diethyl ether solution of magnesium iodide; a polymeric chain-type structure where magnesium is tetrahedrally coordinated, as well as dimeric complex with octahedrally coordinated magnesium. Solvated MgI + is the dominating species in tetrahydrofuran solution. The organomagnesium halides are present in diethyl ether solution as both solvated monomeric and dimeric complexes. Magnesium coordinates a halide ion, an alkyl or aryl group and four solvent molecules octahedrally in the monomeric complex. In the dimeric complex magnesium is octahedrally coordinated by two bridging halide ions, an alkyl or aryl group and three solvent molecules. The distribution of monomeric and dimeric complexes in various solutions are given by a dimerisation constant, K dl . The results indicate that the Schlenk equilibrium is present in these solutions, however, in an extended form. In diethyl ether solution, where MgX 2 does not dissociate, no MgX 2 complex and thereby no Schlenk equilibrium has been observed. In tetrahydrofuran solution MgI 2 has dissociated into mainly MgI + and I - . This indicates that the concentration of MgI 2 is low and that the Schlenk equilibrium should be expanded even further to include the dissociation equilibrium of the magnesium halide. In the thesis Fe K edge EXAFS data collected for the semireduced form of protein A of methane monooxygenase from Methylococcus capsulatus, are also presented. (139 refs.)

  10. An Empirical Study on Entrepreneurial Orientation, Absorptive Capacity, and SMEs’ Innovation Performance: A Sustainable Perspective

    Directory of Open Access Journals (Sweden)

    Yu-Ming Zhai

    2018-01-01

    Full Text Available Using a survey of 324 small and medium-sized enterprises (SMEs of the Yangtze River Delta in China, this study discusses the relationship between entrepreneurial orientation, absorptive capacity, environmental dynamism, and corporate technological innovation performance. The results based on a moderated moderation model show that the relationship between entrepreneurial orientation and innovation performance is significantly positive. The absorptive capacity can positively moderate this relationship. When the external environment is in high dynamism, the moderating effect of absorptive capacity will be stronger than when the environment is in low dynamism.

  11. A structural study of ceramic oxides by X-ray absorption spectroscopy

    International Nuclear Information System (INIS)

    Akhtar, M.J.

    1995-01-01

    A detailed structural study of ceramic oxides is presented by employing X-ray Absorption Spectroscopy (XAS). In the present work X-ray Absorption Near Edge Structure (XANES) is used for the investigation of valence state of metal cations; whereas, Extended X-ray Absorption Fine Structure EXAFS) is employed for the determination for bond lengths, coordination numbers and nature of the elements present in the near neighbour shells surrounding the absorbing atom. These results show that local environment of dopant and host cations are different; and this variation in local structure depends on the nature and concentration of the dopant ions. (author)

  12. X-ray absorption spectroscopy study on the thermal and hydrazine reduction of graphene oxide

    International Nuclear Information System (INIS)

    Liang, Xianqing; Wang, Yu; Zheng, Huiyuan; Wu, Ziyu

    2014-01-01

    Highlights: • XAS study of GO and reduced GO was performed. • Detailed evolution of the electronic structures and chemical bonding of GO was revealed. • A new efficient route for the reduction of GO is proposed. - Abstract: X-ray absorption spectroscopy (XAS) was applied to systemically investigate the deoxygenation of graphene oxide (GO) via annealing and hydrazine treatment. Detailed evolution of the electronic structures and chemical bonding of GO was presented. The enhanced intensity of π * resonance and the appearance of splitting σ * resonance in C K-edge XAS spectra suggest high extents of recoveries of π-conjugation upon reduction using thermal annealing or hydrazine. Experimental results revealed that the carboxyl as well as epoxide and hydroxyl groups on the surface of GO were thermally reduced first, followed by the more difficult removal of carbonyl and cyclic ether groups at higher temperatures. The hydrazine reduction could remove epoxide, hydroxyl and carboxyl groups effectively, whereas the carbonyl groups were partially reduced with the incorporation of nitrogen species simultaneously. The residual oxygen functional groups on hydrazine-reduced GO could be further removed after modest thermal annealing. It was proposed that a combination of both types of reductions would give the best deoxygenation efficiency for the production of graphene

  13. Protonation effects on the UV/Vis absorption spectra of imatinib: a theoretical and experimental study.

    Science.gov (United States)

    Grante, Ilze; Actins, Andris; Orola, Liana

    2014-08-14

    An experimental and theoretical investigation of protonation effects on the UV/Vis absorption spectra of imatinib showed systematic changes of absorption depending on the pH, and a new absorption band appeared below pH 2. These changes in the UV/Vis absorption spectra were interpreted using quantum chemical calculations. The geometry of various imatinib cations in the gas phase and in ethanol solution was optimized with the DFT/B3LYP method. The resultant geometries were compared to the experimentally determined crystal structures of imatinib salts. The semi-empirical ZINDO-CI method was employed to calculate the absorption lines and electronic transitions. Our study suggests that the formation of the extra near-UV absorption band resulted from an increase of imatinib trication concentration in the solution, while the rapid increase of the first absorption maximum could be attributed to both the formation of imatinib trication and tetracation. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Studies on the optical absorption of copper-dopped myoglobin: conformational changes

    International Nuclear Information System (INIS)

    Lamy, M.T.M.

    1976-03-01

    Optical absorption changes in the visible and near U.V. spectrum of myoglobin molecules are observed when copper ions are added to the macromolecule. The heme optical transitions are investigated through a theoretical simulation of the optical absorption spectrum. A study of the absorption band in the region of 700 nm associated with the copper - myoglobin complexes indicated the existence of two kinds of metal-protein complexes: one associated with the six or eitht first added copper ions and the other related with the higher concentrations. Conformational changes caused by thermal treatment are studied in myoglobin water solutions and solutions containing copper ions. The phenomenon named pre-denaturation is observed through the optical absorption at 245 nm. It is shown that interactions between myoglobin molecules occur in the pre-denaturation phenomenon. (Author) [pt

  15. A VISION OF ORKUT´S USERS: STUDYING THIS PHENOMENON THROUGH COGNITIVE ABSORPTION

    Directory of Open Access Journals (Sweden)

    Mauri Leodir Löbler

    2011-05-01

    Full Text Available This study aims to identify the influence that Cognitive Absorption has on the intention of using Orkut. It happens due to the fact that Cognitive Absorption is related to the state of deep involvement users carry with an individual task, performed with the support of Information Technology (IT; it corroborates the study on this virtual community. Therefore, through descriptive research with a quantitative character and with the aid of structural equations, 645 Orkut users were investigated. After the identification of suitability of all indexes tested and fit for both constructs and the final model. The conclusion drawn is that Cognitive Absorption explains the 41% intention of using Orkut, emphasizing that for this kind of IT the Cognitive Absorption seems perfectly adequate to measure the Intention of Use.

  16. Studies concerning thermodynamics and kinetics of the absorption of halogenated hydrocarbons relevant to environment

    International Nuclear Information System (INIS)

    Weisweiler, W.; Eidam, K.; Winterbauer, H.

    1993-07-01

    In the context of the research project the scrubbing of air contaminated by peculiar volatile organic compounds was investigated using the absorption technique by means of high boiling organics as washing liquids. Eight chlorinated hydrocarbons well known from technical processes were chosen to be representative for the volatile organic compounds. Eleven absorption media were selected on the basis of their physical properties. For the determination of the solubility data of the absorption media due to chlorinated hydrocarbons, nitrogen as well as a mixture of nitrogen and oxygen were used as carrier gas. The influence of the dipole moment of the absorption media on the amount of solubility - expressed as enrichment factor - was studied, too. Concerning the technical application, the thermostability and the stability against diluted inorganic acids were studied as well. (orig.). 56 figs., 8 tabs., 63 refs [de

  17. Studies on intestinal absorption in postoperative patients with carcinoma of esophagus and gastric cardia

    Energy Technology Data Exchange (ETDEWEB)

    Yoshimura, Y; Inoguchi, T [Kurume Univ., Fukuoka (Japan). School of Medicine

    1974-08-01

    The function of intestinal absorption and gastric and pancreatic secretion were observed to evaluate several factors affected to intestinal absorption in cases of carcinoma of esophagus and gastric cardia after operation. To compare fat absorption and assimilation between medium chain triglyceride (MCT) and long chain triglyceride (LCT), /sup 14/C-labeled fats were used. The effect of different types of anastomosis; i.e. Billroth I and Billroth II type-pathway, and also the effect of truncal vagotomy on digestion and absorption of fats was studied. In results, the types of anastomosis and truncal vagotomy had no significant effect on digestion and absorption of carbohydrate, but the digestion and absorption of protein and fat were impaired after operation, especially in fat. In Billroth I type-pathway, the impaired digestion and absorption were slight. In Billroth II type-pathway, imbalance in the mixing time of the diet and the digestive juice according to the dumping of ingested food into jejunum and quick passage through the jejunum; so called pancreatico-cibal asynchrony, probably caused impaired digestion of fat. It was considered that truncal vagotomy had caused steatorrhea in the early stage of postoperation. Gastric remnant and reconstructive stomach almost lost its secretory function after operation of esophageal cancer, but pancreatic exocrine secretory function remained after vagotomy. Intestinal absorption of MCT was better than it was of LCT even in cases of postoperative malabsorption. So MCT administration is considered as effective method for caloric intake in cases of esophageal cancer and cancer of gastric cardia, which have operative risk and take long time for the recovery in the function of digestion and absorption after operation. (auth)

  18. Stratum corneum damage and ex vivo porcine skin water absorption - a pilot study

    DEFF Research Database (Denmark)

    Duch Lynggaard, C; Bang Knudsen, D; Jemec, G B E

    2009-01-01

    A simple ex vivo screening technique would be of interest for mass screening of substances for potential barrier disruptive qualities. Ex vivo water absorption as a marker of skin barrier integrity was studied on pig ear skin. Skin water absorption was quantified by weighing and weight changes were...... found to reflect prehydration barrier damage. It is suggested that this simple model may be elaborated to provide a rapid, economical screening tool for potential skin irritants....

  19. Topical absorption and toxicity studies of jet fuel hydrocarbons in skin

    Science.gov (United States)

    Muhammad, Faqir

    Kerosene-based fuels have been used for many decades. Over 2 million military and civilian personnel each year are occupationally exposed to various jet fuel mixtures. Dermatitis is one of the major health concerns associated with these exposures. In the past, separate absorption and toxicity studies have been conducted to find the etiology of such skin disorders. There was a need for integrated absorption and toxicity studies to define the causative constituents of jet fuel responsible for skin irritation. The focus of this thesis was to study the percutaneous absorption and to identify the hydrocarbons (HC) causing irritation in jet fuels so that preventive measures could be taken in the future. The initial study was conducted to understand the possible mechanism for additive interactions on hydrocarbon absorption/disposition in silastic, porcine skin and isolated perfused porcine skin flap (IPPSF) models. The influence of JP-8 (100) additives (MDA, BHT, 8Q405) on the dermal kinetics of 14C-naphthalene and 14C/3H-dodecane as markers of HC absorption was evaluated. This study indicated that individual and combination of additives influenced marker disposition in different membranes. MDA was a significant suppressor while BHT was a significant enhancer of naphthalene absorption in IPPSF. The 8Q405 significantly reduced naphthalene content in dosed silastic and skin indicating a direct interaction between additive and marker HC. Similarly, the individual MDA and BHT significantly retained naphthalene in the stratum corneum of porcine skin, but the combination of both of these additives statistically decreased the marker retention in the stratum corneum suggesting a potential biological interaction. This study concluded that all components of a chemical mixture should be assessed since the effects of single components administered alone or as pairs may be confounded when all are present in the complete mixture. However, this study indicated that the marker HC

  20. Sound absorption study on acoustic panel from kapok fiber and egg tray

    Science.gov (United States)

    Kaamin, Masiri; Mahir, Nurul Syazwani Mohd; Kadir, Aslila Abd; Hamid, Nor Baizura; Mokhtar, Mardiha; Ngadiman, Norhayati

    2017-12-01

    Noise also known as a sound, especially one that is loud or unpleasant or that causes disruption. The level of noise can be reduced by using sound absorption panel. Currently, the market produces sound absorption panel, which use synthetic fibers that can cause harmful effects to the health of consumers. An awareness of using natural fibers from natural materials gets attention of some parties to use it as a sound absorbing material. Therefore, this study was conducted to investigate the potential of sound absorption panel using egg trays and kapok fibers. The test involved in this study was impedance tube test which aims to get sound absorption coefficient (SAC). The results showed that there was good sound absorption at low frequency from 0 Hz up to 900 Hz where the maximum absorption coefficient was 0.950 while the maximum absorption at high frequencies was 0.799. Through the noise reduction coefficient (NRC), the material produced NRC of 0.57 indicates that the materials are very absorbing. In addition, the reverberation room test was carried out to get the value of reverberation time (RT) in unit seconds. Overall this panel showed good results at low frequencies between 0 Hz up to 1500 Hz. In that range of frequency, the maximum reverberation time for the panel was 3.784 seconds compared to the maximum reverberation time for an empty room was 5.798 seconds. This study indicated that kapok fiber and egg tray as the material of absorption panel has a potential as environmental and cheap products in absorbing sound at low frequency.

  1. Study on CO{sub 2} absorption enhancement by adding active carbon particles into MEA solution

    Energy Technology Data Exchange (ETDEWEB)

    Qian, Juan; Sun, Rui; Ma, Lian; Sun, Shaozeng [Harbin Institute of Technology, Harbin (China). School of Energy Science and Engineering

    2013-07-01

    The chemical absorption of CO{sub 2} is generally recognized as the most efficient post-combustion technology of CO{sub 2} separation at present. A study on CO{sub 2} absorption enhancement by adding small particles of active carbon into MEA solution is investigated within a self-designed glass stirring tank. Experiments of different particle loadings and different particle sizes have been conducted. When active carbon particle concentration is fewer, compared to the absorption rate of CO{sub 2} gas absorbed by MEA aqueous solution, the role of active carbon adsorption CO{sub 2} gas is negligible. The enhancement efficiency of CO{sub 2} absorption could be improved by 10% to the upmost in this liquid-particle system.

  2. Study of absorption and re-emission processes in a ternary liquid scintillation system

    International Nuclear Information System (INIS)

    Xiao Hualin; Wang Naiyan; Li Xiaobo; Cao Jun; Wen Liangjian; Zheng Dong

    2010-01-01

    Liquid scintillators are widely used as the neutrino target in neutrino experiments. The absorption and emission of different components of a ternary liquid scintillator (Linear Alkyl Benzene (LAB) as the solvent, 2, 5-diphenyloxazole (PPO) as the fluor and p-bis-(o-methylstyryl)-benzene (bis-MSB) as wavelength shifter) are studied. It is shown that the absorption of this liquid scintillator is dominant by LAB and PPO at wavelengths less than 349 nm, and the absorption by bis-MSB becomes prevalent at the wavelength larger than 349 nm. The fluorescence quantum yields, which are the key parameters to model the absorption and re-emission processes in large liquid scintillation detectors, are measured. (authors)

  3. Distinct intestinal adaptation for vitamin B12 and bile acid absorption revealed in a new mouse model of massive ileocecal resection.

    Science.gov (United States)

    Matsumoto, Yuka; Mochizuki, Wakana; Akiyama, Shintaro; Matsumoto, Taichi; Nozaki, Kengo; Watanabe, Mamoru; Nakamura, Tetsuya

    2017-09-15

    Ileocecal resection (ICR), one of several types of intestinal resection that results in short bowel syndrome (SBS), causes severe clinical disease in humans. We here describe a mouse model of massive ICR in which 75% of the distal small intestine is removed. We demonstrate that mice underwent 75% ICR show severe clinical signs and high mortality, which may recapitulate severe forms of human SBS, despite an adaptive response throughout the remnant intestine. By using this model, we also investigated whether the epithelium of the remnant intestine shows enhanced expression of factors involved in region-specific functions of the ileum. Cubn mRNA and its protein product, which play an essential role in vitamin B12 absorption in the ileum, are not compensatory up-regulated in any part of the remnant intestine, demonstrating a clear contrast with post-operative up-regulation of genes involved in bile acid absorption. Our study suggests that functional adaptation by phenotypical changes in the intestinal epithelium is not a general feature for nutrient absorption systems that are confined to the ileum. We also propose that the mouse model developed in this study will become a unique system to facilitate studies on SBS with ICR in humans. © 2017. Published by The Company of Biologists Ltd.

  4. Distinct intestinal adaptation for vitamin B12 and bile acid absorption revealed in a new mouse model of massive ileocecal resection

    Directory of Open Access Journals (Sweden)

    Yuka Matsumoto

    2017-09-01

    Full Text Available Ileocecal resection (ICR, one of several types of intestinal resection that results in short bowel syndrome (SBS, causes severe clinical disease in humans. We here describe a mouse model of massive ICR in which 75% of the distal small intestine is removed. We demonstrate that mice underwent 75% ICR show severe clinical signs and high mortality, which may recapitulate severe forms of human SBS, despite an adaptive response throughout the remnant intestine. By using this model, we also investigated whether the epithelium of the remnant intestine shows enhanced expression of factors involved in region-specific functions of the ileum. Cubn mRNA and its protein product, which play an essential role in vitamin B12 absorption in the ileum, are not compensatory up-regulated in any part of the remnant intestine, demonstrating a clear contrast with post-operative up-regulation of genes involved in bile acid absorption. Our study suggests that functional adaptation by phenotypical changes in the intestinal epithelium is not a general feature for nutrient absorption systems that are confined to the ileum. We also propose that the mouse model developed in this study will become a unique system to facilitate studies on SBS with ICR in humans.

  5. Parameter study of self-absorption effects in Total Reflection X-ray Fluorescence-X-ray Absorption Near Edge Structure analysis of arsenic

    International Nuclear Information System (INIS)

    Meirer, F.; Pepponi, G.; Streli, C.; Wobrauschek, P.; Kregsamer, P.; Zoeger, N.; Falkenberg, G.

    2008-01-01

    Total reflection X-ray Fluorescence (TXRF) analysis in combination with X-ray Absorption Near Edge Structure (XANES) analysis is a powerful method to perform chemical speciation studies at trace element levels. However, when measuring samples with higher concentrations and in particular standards, damping of the oscillations is observed. In this study the influence of self-absorption effects on TXRF-XANES measurements was investigated by comparing measurements with theoretical calculations. As(V) standard solutions were prepared at various concentrations and dried on flat substrates. The measurements showed a correlation between the damping of the oscillations and the As mass deposited. A Monte-Carlo simulation was developed using data of the samples shapes obtained from confocal white light microscopy. The results showed good agreement with the measurements; they confirmed that the key parameters are the density of the investigated atom in the dried residues and the shape of the residue, parameters that combined define the total mass crossed by a certain portion of the incident beam. The study presents a simple approach for an a priori evaluation of the self-absorption in TXRF X-ray absorption studies. The consequences for Extended X-ray Absorption Fine Structure (EXAFS) and XANES measurements under grazing incidence conditions are discussed, leading to the conclusion that the damping of the oscillations seems to make EXAFS of concentrated samples non feasible. For XANES 'fingerprint' analysis samples should be prepared with a deposited mass and sample shape leading to an acceptable absorption for the actual investigation

  6. Structural investigations of LiFePO4 electrodes and in situ studies by Fe X-ray absorption spectroscopy

    International Nuclear Information System (INIS)

    Deb, Aniruddha; Bergmann, Uwe; Cramer, S.P.; Cairns, Elton J.

    2005-01-01

    Fe K-edge X-ray absorption near edge spectroscopy (XANES) and extended X-ray absorption fine structure (EXAFS) have been performed on electrodes containing LiFePO 4 to determine the local atomic and electronic structure and their stability with electrochemical cycling. A versatile electrochemical in situ cell has been constructed for long-term soft and hard X-ray experiments for the structural investigation on battery electrodes during the lithium-insertion/extraction processes. The device is used here for an X-ray absorption spectroscopic study of lithium insertion/extraction in a LiFePO 4 electrode, where the electrode contained about 7.7 mg of LiFePO 4 on a 20 μm thick Al-foil. Fe K-edge X-ray absorption near edge spectroscopy (XANES) and extended X-ray absorption fine structure (EXAFS) have been performed on this electrode to determine the local atomic and electronic structure and their stability with electrochemical cycling. The initial state (LiFePO 4 ) showed iron to be in the Fe 2+ state corresponding to the initial state (0.0 mAh) of the cell, whereas in the delithiated state (FePO 4 ) iron was found to be in the Fe 3+ state corresponding to the final charged state (3 mAh). XANES region of the XAS spectra revealed a high spin configuration for the two states (Fe (II), d 6 and Fe (III), d 5 ). The results confirm that the olivine structure of the LiFePO 4 and FePO 4 is retained by the electrodes in agreement with the XRD observations reported previously. These results confirm that LiFePO 4 cathode material retains good structural short-range order leading to superior cycling capability

  7. Study of Material Moisture Measurement Method and Instrument by the Combination of Fast Neutron Absorption and γ Absorption

    International Nuclear Information System (INIS)

    Hou Chaoqin; Gong Yalin; Zhang Wei; Shang Qingmin; Li Yanfeng; Gou Qiangyuan; Yin Deyou

    2010-01-01

    To solve the problem of on-line sinter moisture measurement in the iron making plant, we developed material moisture measurement method and instrument by the combination of fast neutron absorption and y-absorption. It overcomes the present existed problems of other moisture meters for the sinter. Compare with microwave moisture meter, the measurement dose not affected by conductance and magnetism of material; to infrared moisture meter, the measurement result dose not influenced by colour and light-reflect performance of material surface, dose not influenced by changes of material kind; to slow neutron scatter moisture meter, the measurement dose not affected by density of material and thickness of hopper wall; to the moisture measurement meter which combined by slow neutron penetrate through and y-absorption, there are definite math model and good linear relation between the measurement values, and the measurement dose not affected by material thickness, changes of material form and component. (authors)

  8. Folate absorption

    International Nuclear Information System (INIS)

    Baker, S.J.

    1976-01-01

    Folate is the generic term given to numerous compounds of pteroic acid with glutamic acid. Knowledge of absorption is limited because of the complexities introduced by the variety of compounds and because of the inadequacy of investigational methods. Two assay methods are in use, namely microbiological and radioactive. Techniques used to study absorption include measurement of urinary excretion, serum concentration, faecal excretion, intestinal perfusion, and haematological response. It is probably necessary to test absorption of both pteroylmonoglutamic acid and one or more polyglutamates, and such tests would be facilitated by availability of synthesized compounds labelled with radioactive tracers at specifically selected sites. (author)

  9. Nonlinear absorption, optical limiting behavior and structural study of a new chalcone derivative-1-(3, 4-dimethylphenyl)-3-[4(methylsulfanyl) phenyl] prop-2-en-1-one

    Science.gov (United States)

    Chandra Shekhara Shetty, T.; Raghavendra, S.; Chidan Kumar, C. S.; Dharmaprakash, S. M.

    2016-03-01

    A new third order nonlinear optical (NLO) organic material-1-(3, 4-dimethylphenyl)-3-[4(methylsulfanyl) phenyl] prop-2-en-1-one (4DPMS) belonging to chalcone family has been crystallized in acetone solution. The 4DPMS crystals are characterized by CHNS analysis, FTIR, UV-visible spectral and thermal techniques. The single crystal X-ray diffraction study reveals that 4DPMS crystallizes in monoclinic system with P21/n space group. The linear optical absorption spectrum revealed that the 4DPMS crystals are transparent in the entire visible region. Thermogravimetric data shows absence of phase transition before melting point and from differential scanning calorimetry analysis the melting point of the crystal is found to be 106 °C. Third order nonlinear absorption and optical limiting experiment on 4DPMS was carried out using open aperture Z-scan technique with Nd: YAG laser operating at 532 nm. It was found that the calculated values of excited state absorption cross section for 4DPMS molecules is much greater than the ground state absorption cross section. A decrease in effective nonlinear absorption coefficient was observed with increase in the input irradiance of laser. The observed optical limiting property in 4DPMS is attributed to reverse saturable absorption.

  10. Determination of equilibrium structures of bromothymol blue revealed by using quantum chemistry with an aid of multivariate analysis of electronic absorption spectra.

    Science.gov (United States)

    Shimada, Toru; Hasegawa, Takeshi

    2017-10-05

    The pH dependent chemical structures of bromothymol blue (BTB), which have long been under controversy, are determined by employing a combined technique of multivariate analysis of electronic absorption spectra and quantum chemistry. Principle component analysis (PCA) of the pH dependent spectra apparently reveals that only two chemical species are adequate to fully account for the color changes, with which the spectral decomposition is readily performed by using augmented alternative least-squares (ALS) regression analysis. The quantity variation by the ALS analysis also reveals the practical acid dissociation constant, pK a '. The determination of pK a ' is performed for various ionic strengths, which reveals the thermodynamic acid constant (pK a =7.5) and the number of charge on each chemical species; the yellow form is negatively charged species of -1 and the blue form that of -2. On this chemical information, the quantum chemical calculation is carried out to find that BTB molecules take the pure quinoid form in an acid solution and the quinoid-phenolate form in an alkaline solution. The time-dependent density functional theory (TD-DFT) calculations for the theoretically determined chemical structures account for the peak shift of the electronic spectra. In this manner, the structures of all the chemical species appeared in equilibrium have finally been confirmed. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Determination of equilibrium structures of bromothymol blue revealed by using quantum chemistry with an aid of multivariate analysis of electronic absorption spectra

    Science.gov (United States)

    Shimada, Toru; Hasegawa, Takeshi

    2017-10-01

    The pH dependent chemical structures of bromothymol blue (BTB), which have long been under controversy, are determined by employing a combined technique of multivariate analysis of electronic absorption spectra and quantum chemistry. Principle component analysis (PCA) of the pH dependent spectra apparently reveals that only two chemical species are adequate to fully account for the color changes, with which the spectral decomposition is readily performed by using augmented alternative least-squares (ALS) regression analysis. The quantity variation by the ALS analysis also reveals the practical acid dissociation constant, pKa‧. The determination of pKa‧ is performed for various ionic strengths, which reveals the thermodynamic acid constant (pKa = 7.5) and the number of charge on each chemical species; the yellow form is negatively charged species of - 1 and the blue form that of - 2. On this chemical information, the quantum chemical calculation is carried out to find that BTB molecules take the pure quinoid form in an acid solution and the quinoid-phenolate form in an alkaline solution. The time-dependent density functional theory (TD-DFT) calculations for the theoretically determined chemical structures account for the peak shift of the electronic spectra. In this manner, the structures of all the chemical species appeared in equilibrium have finally been confirmed.

  12. Degradation and Moisture Absorption Study of Potato-starch Linear ...

    African Journals Online (AJOL)

    Composite of linear low density polyethylene (LLDPE) and potato-starch was produced and subjected to degradation studies with the agencies of enzymes, exposure to weather and immersion in water. Enzymatic hydrolysis degraded the matrix to an extent greater than 40% loss in strength and about 20% loss in ...

  13. A theoretical study of absorption equilibria in silicon CVD

    NARCIS (Netherlands)

    Gardeniers, Johannes G.E.; Giling, L.J.; de Jong, F.; van der Eerden, J.P.

    1990-01-01

    As part of a theoretical study of adsorption processes in the chemical vapour deposition of silicon, thermochemical data are derived for the adsorption of Si-H species on the Si(111) and the dimer-reconstructed Si(001)-(2 x 1) surfaces. Essential contributions to the heats of adsorption appear to be

  14. The effect of ISM absorption on stellar activity measurements and its relevance for exoplanet studies

    Science.gov (United States)

    Fossati, L.; Marcelja, S. E.; Staab, D.; Cubillos, P. E.; France, K.; Haswell, C. A.; Ingrassia, S.; Jenkins, J. S.; Koskinen, T.; Lanza, A. F.; Redfield, S.; Youngblood, A.; Pelzmann, G.

    2017-05-01

    Past ultraviolet and optical observations of stars hosting close-in Jupiter-mass planets have shown that some of these stars present an anomalously low chromospheric activity, significantly below the basal level. For the hot Jupiter planet host WASP-13, observations have shown that the apparent lack of activity is possibly caused by absorption from the intervening interstellar medium (ISM). Inspired by this result, we study the effect of ISM absorption on activity measurements (S and log R 'HK indices) for main-sequence late-type stars. To this end, we employ synthetic stellar photospheric spectra combined with varying amounts of chromospheric emission and ISM absorption. We present the effect of ISM absorption on activity measurements by varying several instrumental (spectral resolution), stellar (projected rotational velocity, effective temperature, and chromospheric emission flux), and ISM parameters (relative velocity between stellar and ISM Ca II lines, broadening b-parameter, and Ca II column density). We find that for relative velocities between the stellar and ISM lines smaller than 30-40 km s-1 and for ISM Ca II column densities log NCaII ⪆ 12, the ISM absorption has a significant influence on activity measurements. Direct measurements and three dimensional maps of the Galactic ISM absorption indicate that an ISM Ca II column density of log NCaII = 12 is typically reached by a distance of about 100 pc along most sight lines. In particular, for a Sun-like star lying at a distance greater than 100 pc, we expect a depression (bias) in the log R'HK value larger than 0.05-0.1 dex, about the same size as the typical measurement and calibration uncertainties on this parameter. This work shows that the bias introduced by ISM absorption must always be considered when measuring activity for stars lying beyond 100 pc. We also consider the effect of multiple ISM absorption components. We discuss the relevance of this result for exoplanet studies and revise the

  15. Studies on the absorption, distribution of rare earth elements and its effect on absorption of phosphorus and potassium in sugarcane (Saccharum officnarum L.)

    International Nuclear Information System (INIS)

    Kuang Yanhua; Liu Qiongying; Zheng Yuemei; Deng Zhouhuo; Xu Shengjie

    1991-01-01

    Study on the absorption, distribution and translocation of area earth elements (RE) and their effects on absorption of phosphorus and potassium ( 86 Rb as tracer) in sugarcane showed that the sugarcane could absorb soluble RE fast by its root or leaves. Within the 1-7 days after treatment, the absorption rate of 141 Ce in organs of the plant increased with the time. At the 7th day after treatment, the absorption rate of 141 Ce by sugarcane plant reached the maximum which was about 2-3 times of that at the 1st day and after that it gradually decreased. The utilization efficiency of 141 Ce by sugarcane plant was 0.836-3.24%. The absorption and distribution of RE in sugarcane plant varied with the treatment methods. It was shown that about 90% 141 Ce in nutrient solution was concentrated in the roots while only about 10% of them was transferred into the shoots. The distribution and accumulation of 141 Ce in suggarcene plant was in order of root>stem>leaf. If smeared on the leaf of sugarcane, the distribution and accumulation of 141 Ce in sugarcane plant was in order of leaf>stem>root. When treated with 300, 500 and 800 ppm R(NO 3 ) 3 ·4H 2 O, Ce, La, Sm, Pr, Nd and Y, the absorption and translocation rate of phosphorus and rubidium in sugarcane were increased

  16. A study of phosphate absorption by magnesium iron hydroxycarbonate.

    Science.gov (United States)

    Du, Yi; Rees, Nicholas; O'Hare, Dermot

    2009-10-21

    A study of the mechanism of phosphate adsorption by magnesium iron hydroxycarbonate, [Mg(2.25)Fe(0.75)(OH)(6)](CO(3))(0.37).0.65H(2)O over a range of pH has been carried out. The efficiency of the phosphate removal from aqueous solution has been investigated between pH 3-9 and the resulting solid phases have been studied by elemental analysis, XRD, FT-IR, Raman, HRTEM, EDX and solid-state MAS (31)P NMR. The analytical and spectroscopic data suggest that phosphate removal from solution occurs not by anion intercalation of the relevant phosphorous oxyanion (H(2)PO(4)(-) or HPO(4)(2-)) into the LDH but by the precipitation of either an insoluble iron hydrogen phosphate hydrate and/or a magnesium phosphate hydrate.

  17. Studies of selected transuranium and lanthanide tri-iodides under pressure using absorption spectrophotometry

    International Nuclear Information System (INIS)

    Haire, R.G.; Young, J.P.; Peterson, J.R.; Tennessee Univ., Knoxville; Benedict, U.

    1987-01-01

    The anhydrous tri-iodides of plutonium, americium and curium under pressure have been investigated using absorption spectrophotometry. These initial studies on plutonium and curium tri-iodides together with the published data for americium tri-iodide show that the rhombohedral form of these compounds (BiI 3 -type structure) can be converted to the orthorhombic form (PuBr 3 -type structure) by applying pressure at room temperature. Absorption spectrophotometry can often differentiate between two crystallographic forms of a material and has been used in the present high-pressure studies to monitor the effects of pressure on the tri-iodides. A complication in these studies of the tri-iodides is a significant shift of their absorption edges with pressure from the near UV to the visible spectral region. With curium tri-iodide this shift causes interference with the major f-f absorption peaks and precludes identification by absorption spectrophotometry of the high pressure phase of CmI 3 . (orig.)

  18. X-ray absorption fine structure (XAFS) studies of cobalt silicide thin films

    International Nuclear Information System (INIS)

    Naftel, S.J.; Coulthard, I.; Hu, Y.; Sham, T.K.; Zinke-Allmang, M.

    1998-01-01

    Cobalt silicide thin films, prepared on Si(100) wafers, have been studied by X-ray absorption near edge structures (XANES) at the Si K-, L 2,3 - and Co K-edges utilizing both total electron (TEY) and fluorescence yield (FLY) detection as well as extended X-ray absorption fine structure (EXAFS) at the Co K-edge. Samples made using DC sputter deposition on clean Si surfaces and MBE were studied along with a bulk CoSi 2 sample. XANES and EXAFS provide information about the electronic structure and morphology of the films. It was found that the films studied have essentially the same structure as bulk CoSi 2 . Both the spectroscopy and materials characterization aspects of XAFS (X-ray absorption fine structures) are discussed

  19. Study of Photosensitive Dry Films Absorption for Printed Circuit Boards by Photoacoustic Technique

    Science.gov (United States)

    Hernández, R.; Zaragoza, J. A. Barrientos; Jiménez-Pérez, J. L.; Orea, A. Cruz; Correa-Pacheco, Z. N.

    2017-08-01

    In this work, the study of photosensitive dry-type films by photoacoustic technique is proposed. The dry film photoresist is resistant to chemical etching for printed circuit boards such as ferric chloride, sodium persulfate or ammonium, hydrochloric acid. It is capable of faithfully reproducing circuit pattern exposed to ultraviolet light (UV) through a negative. Once recorded, the uncured portion is removed with alkaline solution. It is possible to obtain good results in surface mount circuits with tracks of 5 mm. Furthermore, the solid resin films are formed by three layers, two protective layers and a UV-sensitive optical absorption layer in the range of 325 nm to 405 nm. By means of optical absorption of UV-visible rays emitted by a low-power Xe lamp, the films transform this energy into thermal waves generated by the absorption of optical radiation and subsequently no-radiative de-excitation occurs. The photoacoustic spectroscopy is a useful technique to measure the transmittance and absorption directly. In this study, the optical absorption spectra of the three layers of photosensitive dry-type films were obtained as a function of the wavelength, in order to have a knowledge of the absorber layer and the protective layers. These analyses will give us the physical properties of the photosensitive film, which are very important in curing the dry film for applications in printed circuit boards.

  20. Myo-inositol inhibits intestinal glucose absorption and promotes muscle glucose uptake: a dual approach study.

    Science.gov (United States)

    Chukwuma, Chika Ifeanyi; Ibrahim, Mohammed Auwal; Islam, Md Shahidul

    2016-12-01

    The present study investigated the effects of myo-inositol on muscle glucose uptake and intestinal glucose absorption ex vivo as well as in normal and type 2 diabetes model of rats. In ex vivo study, both intestinal glucose absorption and muscle glucose uptake were studied in isolated rat jejunum and psoas muscle respectively in the presence of increasing concentrations (2.5 % to 20 %) of myo-inositol. In the in vivo study, the effect of a single bolus dose (1 g/kg bw) of oral myo-inositol on intestinal glucose absorption, blood glucose, gastric emptying and digesta transit was investigated in normal and type 2 diabetic rats after 1 h of co-administration with 2 g/kg bw glucose, when phenol red was used as a recovery marker. Myo-inositol inhibited intestinal glucose absorption (IC 50  = 28.23 ± 6.01 %) and increased muscle glucose uptake, with (GU 50  = 2.68 ± 0.75 %) or without (GU 50  = 8.61 ± 0.55 %) insulin. Additionally, oral myo-inositol not only inhibited duodenal glucose absorption and reduced blood glucose increase, but also delayed gastric emptying and accelerated digesta transit in both normal and diabetic animals. Results of this study suggest that dietary myo-inositol inhibits intestinal glucose absorption both in ex vivo and in normal or diabetic rats and also promotes muscle glucose uptake in ex vivo condition. Hence, myo-inositol may be further investigated as a possible anti-hyperglycaemic dietary supplement for diabetic foods and food products.

  1. Study the multi-photon absorption process in two types of molecules

    International Nuclear Information System (INIS)

    Al-azawi, H.R.

    1986-01-01

    The aim of the present work was to study the multi-photon absorption process in two types of molecules; spherical top such as SF 6 molecules and assymetric top such as CHOOH and C 2 H 4 molecules. This work also aimed to study the effect of buffer gas pressure (Ar), which is transparent to the infrared (IR) laser on the multiphoton absorption of both types of molecules. A pulsed (TEA) CO 2 laser was used as a source which generates multi-lines in the IR-region of the spectrum and an optoacoustic detector was used to detect the energy absorbed by the molecules. In this study, the relaxation process was found to be faster in the heavy molecules than that in the light ones. A limit in the Ar pressure was observed. Below this limit, the gas acted as an active buffer gas and above it, the multi-photon absorption process was quenched. This work also aimed to study the multi-photon absorption spectrum for the CHOOH molecules in the range (1067-1090 cm -1 ). This spectrum was found to be consistent with the linear absorption spectrum obtained for the same range. The density of the vibrational states as a function of the vibrational energy was studied for the molecules SF 6 , CHOOH and C 2 H 4 . The results were used to interpret (i) the difference in the energy absorbed by difference molecules at the same energy density and (ii) the non-linearity in the multi-photon absorption for CHOOH molecules. 1 tab.; 40 figs.; 70 refs

  2. A review of whole-body counting techniques appropriate to the study of gastrointestinal absorption

    International Nuclear Information System (INIS)

    Boddy, K.

    1976-01-01

    The wide range of whole-body counters in use for, or applicable to, the study of gastrointestinal absorption is reviewed. Shielded-room or high-sensitivity shadow-shield counters will generally be required only when there is a separate need to measure total body potassium or in studies involving pregnancy or children. For measuring gastrointestinal absorption per se, it is concluded that very simple whole-body counters of the shadow-shield or partial-shield type are usually satisfactory. These systems are of lower cost, and an economic justification for their use is derived by comparing their costs with those of hospitalizing patients for alternative investigations of gastrointestinal absorption. A resume of the general methodology is presented and some operational features and precautions are described. (author)

  3. Performance evaluation and mass transfer study of CO2 absorption in flat sheet membrane contactor using novel porous polysulfone membrane

    International Nuclear Information System (INIS)

    Nabian, Nima; Ghoreyshi, Ali Asghar; Rahimpour, Ahmad; Shakeri, Mohsen

    2015-01-01

    The performance of gas-liquid membrane contactor for CO 2 capture was investigated using a novel polysulfone (PSF) flat membrane prepared via non-solvent phase inversion method. Polyvinyl pyrrolidone (PVP) was used as an additive in the dope solution of PSF membranes. Morphological studies by scanning electron microscopy (SEM) analysis revealed that PSF membrane with PVP has a finger-like structure, but the PSF membrane without PVP has a sponge-like structure. Also, characterization results through atomic force microscopy (AFM) and contact angle measurement demonstrated that the porosity, surface roughness and hydrophobicity of the PSF membrane increased with addition of PVP to the dope solution. Mass transfer resistance analysis, based on CO 2 absorption flux, displayed that addition of PVP to the dope solution of PSF membrane decreased membrane mass transfer resistance, and significantly improved CO 2 absorption flux up to 2.7 and 1.8 times of absorption fluxes of PSF membrane without PVP and commercial PVDF, respectively.

  4. On the Influence of the Sample Absorptivity when Studying the Thermal Degradation of Materials

    Directory of Open Access Journals (Sweden)

    Pascal Boulet

    2015-08-01

    Full Text Available The change in absorptivity during the degradation process of materials is discussed, and its influence as one of the involved parameters in the degradation models is studied. Three materials with very different behaviors are used for the demonstration of its role: a carbon composite material, which is opaque, almost grey, a plywood slab, which is opaque and spectral-dependent and a clear PMMA slab, which is semitransparent. Data are analyzed for virgin and degraded materials at different steps of thermal degradation. It is seen that absorptivity and emissivity often reach high values in the range of 0.90–0.95 with a near-grey behavior after significant thermal aggression, but depending on the materials of interest, some significant evolution may be first observed, especially during the early stages of the degradation. Supplementary inaccuracy can come from the heterogeneity of the incident flux on the slab. As a whole, discrepancies up to 20% can be observed on the absorbed flux depending on the degradation time, mainly because of the spectral variations of the absorption and up to 10% more, depending on the position on the slab. Simple models with a constant and unique value of absorptivity may then lead to inaccuracies in the evaluation of the radiative flux absorption, with possible consequences on the pyrolysis analysis, especially for properties related to the early step of the degradation process, like the time to ignition, for example.

  5. On the Influence of the Sample Absorptivity when Studying the Thermal Degradation of Materials.

    Science.gov (United States)

    Boulet, Pascal; Brissinger, Damien; Collin, Anthony; Acem, Zoubir; Parent, Gilles

    2015-08-21

    The change in absorptivity during the degradation process of materials is discussed, and its influence as one of the involved parameters in the degradation models is studied. Three materials with very different behaviors are used for the demonstration of its role: a carbon composite material, which is opaque, almost grey, a plywood slab, which is opaque and spectral-dependent and a clear PMMA slab, which is semitransparent. Data are analyzed for virgin and degraded materials at different steps of thermal degradation. It is seen that absorptivity and emissivity often reach high values in the range of 0.90-0.95 with a near-grey behavior after significant thermal aggression, but depending on the materials of interest, some significant evolution may be first observed, especially during the early stages of the degradation. Supplementary inaccuracy can come from the heterogeneity of the incident flux on the slab. As a whole, discrepancies up to 20% can be observed on the absorbed flux depending on the degradation time, mainly because of the spectral variations of the absorption and up to 10% more, depending on the position on the slab. Simple models with a constant and unique value of absorptivity may then lead to inaccuracies in the evaluation of the radiative flux absorption, with possible consequences on the pyrolysis analysis, especially for properties related to the early step of the degradation process, like the time to ignition, for example.

  6. Experimental study on the sound absorption characteristics of continuously graded phononic crystals

    Directory of Open Access Journals (Sweden)

    X. H. Zhang

    2016-10-01

    Full Text Available Novel three-dimensional (3D continuously graded phononic crystals (CGPCs have been designed, and fabricated by 3D printing. Each of the CGPCs is an entity instead of a combination of several other samples, and the porosity distribution of the CGPC along the incident direction is nearly linear. The sound absorption characteristics of CGPCs were experimentally investigated and compared with those of uniform phononic crystals (UPCs and discretely stepped phononic crystals (DSPCs. Experimental results show that CGPCs demonstrate excellent sound absorption performance because of their continuously graded structures. CGPCs have higher sound absorption coefficients in the large frequency range and more sound absorption coefficient peaks in a specific frequency range than UPCs and DSPCs. In particular, the sound absorption coefficients of the CGPC with a porosity of 0.6 and thickness of 30 mm are higher than 0.56 when the frequency is 1350–6300 Hz and are all higher than 0.2 in the studied frequency range (1000–6300 Hz. CGPCs are expected to have potential application in noise control, especially in the broad frequency and low-frequency ranges.

  7. Study of plasma-based stable and ultra-wideband electromagnetic wave absorption for stealth application

    Science.gov (United States)

    Xuyang, CHEN; Fangfang, SHEN; Yanming, LIU; Wei, AI; Xiaoping, LI

    2018-06-01

    A plasma-based stable, ultra-wideband electromagnetic (EM) wave absorber structure is studied in this paper for stealth applications. The stability is maintained by a multi-layer structure with several plasma layers and dielectric layers distributed alternately. The plasma in each plasma layer is designed to be uniform, whereas it has a discrete nonuniform distribution from the overall view of the structure. The nonuniform distribution of the plasma is the key to obtaining ultra-wideband wave absorption. A discrete Epstein distribution model is put forward to constrain the nonuniform electron density of the plasma layers, by which the wave absorption range is extended to the ultra-wideband. Then, the scattering matrix method (SMM) is employed to analyze the electromagnetic reflection and absorption of the absorber structure. In the simulation, the validation of the proposed structure and model in ultra-wideband EM wave absorption is first illustrated by comparing the nonuniform plasma model with the uniform case. Then, the influence of various parameters on the EM wave reflection of the plasma are simulated and analyzed in detail, verifying the EM wave absorption performance of the absorber. The proposed structure and model are expected to be superior in some realistic applications, such as supersonic aircraft.

  8. A laboratory experimental setup for photo-absorption studies using synchrotron radiation

    CERN Document Server

    Shastri, A; Saraswati, P; Sunanda, K

    2002-01-01

    The photophysics beamline, which is being installed at the 450 MeV Synchrotron Radiation Source (SRS), Indus-l, is a medium resolution beamline useful for a variety of experiments in the VUV region viz. 500-2000 A. One of the major applications of this beamline is gas-phase photo-absorption studies. An experimental set up to be used for these experiments was designed, developed and tested in our laboratory. The setup consists of a high vacuum absorption cell, 1/4 m monochromator and detection system. For the purpose of testing, xenon and tungsten continuum sources were used and absorption spectra were recorded in the UV region. This setup was used to record the absorption spectrum of a few molecules like acetone, ammonia, benzene, formaldehyde and acetaldehyde in order to evaluate the performance of the experimental system which will subsequently be used with the photophysics beamline. Details of the design, fabrication and testing of the absorption cell and experimental procedures are presented in this repor...

  9. Soft x-ray irradiation effects of Li₂O₂, Li₂CO₃ and Li₂O revealed by absorption spectroscopy.

    Directory of Open Access Journals (Sweden)

    Ruimin Qiao

    Full Text Available Li(2O(2, Li(2CO(3, and Li(2O are three critical compounds in lithium-air and lithium-ion energy storage systems. Extensive measurements have been carried out to study the chemical species and their evolutions at difference stages of the device operation. While x-ray spectroscopy has been demonstrated to be one of the most powerful tools for such purpose, no systematic study on the irradiation effects have been reported. Here we carry out extensive time, position, and irradiation dependent Li K-edge soft x-ray absorption spectroscopy on these compounds with so far the best energy resolution. The ultra-high resolution in the current study allows the features in the absorption spectra to be well-resolved. The spectral lineshape thus serves as the fingerprints of these compounds, enabling the tracking of their evolution under x-ray irradiation. We found that both Li(2O(2 and Li(2CO(3 evidently evolve towards Li(2O under the soft x-ray irradiation with Li(2CO(3 exhibiting a surprisingly higher sensitivity to x-rays than Li(2O(2. On the other hand, Li(2O remains the most stable compound despite experiencing substantial irradiation dose. We thus conclude that high resolution soft x-ray spectroscopy could unambiguously fingerprint different chemical species, but special cautions on irradiation effects would be needed in performing the experiments and interpreting the data properly.

  10. Basic studies on digestion and absorption in the small intestine, 7

    International Nuclear Information System (INIS)

    Ohki, Masahisa

    1980-01-01

    The absorption of 14 C-labeled fatty acids (caproic acid, oleic acid and stearic acid) was investigated. These were emulsified with an ultrasonic mixer for 60 min, and intestine treated with physiological saline and 10% pluronic F68 solution was used. Caproic acid was absorbed very rapidly and solely through the portal vein. Oleic acid and stearic acid were absorbed slowly through the lymphatics, with the former being absorbed faster. In physiological saline-treated intestine, oleic acid was transported into both the portal vein and lymphatic ducts. 10% Pluronic F68 solution did not change the absorption of caproic acid and oleic acid, but accelerated that of stearic acid. Autoradiographic studies demonstrated that each fatty acid was absorbed into absorptive cells in a different fashion, and long chain fatty acids required a long period of time for transport from the intestinal cells to the circulating blood. (author)

  11. Studies of Water Absorption Behavior of Plant Fibers at Different Temperatures

    Science.gov (United States)

    Saikia, Dip

    2010-05-01

    Moisture absorption of natural fiber plastic composites is one major concern in their outdoor applications. The absorbed moisture has many detrimental effects on the mechanical performance of these composites. A knowledge of the moisture diffusivity, permeability, and solubility is very much essential for the application of natural fibers as an excellent reinforcement in polymers. An effort has been made to study the water absorption behavior of some natural fibers such as bowstring hemp, okra, and betel nut at different temperatures to improve the long-term performance of composites reinforced with these fibers. The gain in moisture content in the fibers due to water absorption was measured as a function of exposure time at temperatures ranging from 300 K to 340 K. The thermodynamic parameters of the sorption process, such as diffusion coefficients and corresponding activation energies, were estimated.

  12. X-ray absorption study of the electronic structure of Mn-doped amorphous Si

    Energy Technology Data Exchange (ETDEWEB)

    Arenholz, Elke; Zeng, Li; Huegel, A.; Helgren, E.; Hellman, F.; Piamonteze, C.; Arenholz, E.

    2008-03-08

    The electronic structure of Mn in amorphous Si (a-Mn{sub x}Si{sub 1?x}) is studied by X-ray absorption spectroscopy at the Mn L{sub 3,2} edges for x = 0.005-0.18. Except the x = 0.005 sample, which shows a slight signature of Mn{sup 2+} atomic multiplets associated with a local Mn moment, all samples have broad and featureless L{sub 3,2} absorption peaks, corresponding to an itinerant state for all 3d electrons. The broad X-ray absorption spectra exclude the possibility of a localized 3d moment and explain the unexpectedly quenched Mn moment in this magnetically-doped amorphous semiconductor. Such a fully delocalized d state of Mn dopant in Si has not been previously suggested.

  13. A preliminary study of iron absorption by whole body counting and correlation with DFO excretion

    International Nuclear Information System (INIS)

    Gupta, M.M.; Bhattacharyya, L.; Gupta, N.K.; Bhola, G.C.; Nagaratnam, A.; Manchanda, R.; Bhargva, M.; Kumar, S.

    1975-01-01

    A preliminary study of iron absorption by oral administration of 59 Fe and whole body counting was carried on a group of 16 women. The cases included 8 patients suffering from iron deficiency anaemia and various infections as well as 8 healthy controls. High iron absorption is associated with iron deficiency, these changes being more marked in iron deficient controls than in those with infection or malignancy. In iron deficient controls results of whole body counting correlate very well with other haematological investigations. (orig.) [de

  14. $\\beta$-decay studies using total absorption techniques some recent results

    CERN Document Server

    Algora, A; García-Borge, M J; Cano-Ott, D; Collatz, R; Courtin, S; Dessagne, P; Fraile-Prieto, L M; Gadea, A; Gelletly, W; Hellström, M; Janas, Z; Jungclaus, A; Karny, M; Kirchner, R; Maréchal, F; Miehé, C; Moroz, F; Nacher, E; Poirier, E; Roeckl, E; Rubio, B; Rykaczewski, K; Scornet, G L; Taín, J L; Tengblad, O; Wittmann, V

    2004-01-01

    $\\beta$-decay experiments, are a primary source of information for nuclear structure studies and at the same time complementary to in-beam investigations far from stability. Although both types of experiment are mainly based on $\\gamma$-ray spectroscopy, they face different experimental problems. The so-called $\\textit{Pandemonium effect}$ is a critical problem in $\\beta$-decay. In this contribution we will present a solution to this problem using total absorption spectroscopy methods. We will also present some examples of experiments carried out with the total absorption spectrometers TAS at GSI and Lucrecia recently installed at CERN. (25 refs).

  15. Beta-decay studies using total absorption techniques: some recent results

    Energy Technology Data Exchange (ETDEWEB)

    Algora, A.; Rubio, B.; Nacher, E.; Cano O, D.; Tain, J.L.; Gadea, A. [lnstituto de Fisica Corpuscular, Apartado Oficial 22085, 46071 Valencia (Spain); Batist, L.; Moroz, F.; Wittmann, V. [St. Petersburg Nuclear Physics Institute, RU-188-350 Gatchina, (Russian Federation); Borge, M.J.G.; Jungclaus, A.; Tengblad, O. [Instituto Estructura de la Materia, E-28006 Madrid (Spain); Collatz, R.; Hellstrom, M.; Kirchner, R.; Roeckl, E. [Gesellschaft fur Schwerionenforschung, D-64291 Darmstadt (Germany); Courtin, H.; Dessagne, Ph.; Miehe, C.; Marechal, F.; Poirier, E. [lnstitut de Recherches Subatomiques, IN2P3-CNRS, F-67037 Strassbourg Cedex 2 (France); Fraile, L.M. [ISOLDE, Division EP, CERN, CH-1211 Geneva (Switzerland); Gelletly, W. [University of Surrey, Guildford GU2 7XH (United Kingdom); Janas, Z.; Karny, M.; Rykaczewski, K. [University of Warsaw, PL-00-681, Warsaw (Poland); Le Scornet, G. [CSNSM, 91405 Orsay (France)

    2004-12-01

    Beta-decay experiments are a primary source of information for nuclear structure studies and at the same time complementary to in-beam investigations far from stability. Although both types of experiment are mainly based on {gamma} ray spectroscopy, they face different experimental problems. The so called Pandemonium effect [1] is a critical problem in {beta}-decay. In this contribution we will present a solution to this problem using total absorption spectroscopy methods. We will also present some examples of experiments carried out with the total absorption spectrometers TAS at GSI and Lucrecia recently installed at CERN. (Author) 25 refs., 4 figs.

  16. Effects of sampling methods on the quantity and quality of dissolved organic matter in sediment pore waters as revealed by absorption and fluorescence spectroscopy.

    Science.gov (United States)

    Chen, Meilian; Lee, Jong-Hyeon; Hur, Jin

    2015-10-01

    Despite literature evidence suggesting the importance of sampling methods on the properties of sediment pore waters, their effects on the dissolved organic matter (PW-DOM) have been unexplored to date. Here, we compared the effects of two commonly used sampling methods (i.e., centrifuge and Rhizon sampler) on the characteristics of PW-DOM for the first time. The bulk dissolved organic carbon (DOC), ultraviolet-visible (UV-Vis) absorption, and excitation-emission matrixes coupled with parallel factor analysis (EEM-PARAFAC) of the PW-DOM samples were compared for the two sampling methods with the sediments from minimal to severely contaminated sites. The centrifuged samples were found to have higher average values of DOC, UV absorption, and protein-like EEM-PARAFAC components. The samples collected with the Rhizon sampler, however, exhibited generally more humified characteristics than the centrifuged ones, implying a preferential collection of PW-DOM with respect to the sampling methods. Furthermore, the differences between the two sampling methods seem more pronounced in relatively more polluted sites. Our observations were possibly explained by either the filtration effect resulting from the smaller pore size of the Rhizon sampler or the desorption of DOM molecules loosely bound to minerals during centrifugation, or both. Our study suggests that consistent use of one sampling method is crucial for PW-DOM studies and also that caution should be taken in the comparison of data collected with different sampling methods.

  17. The team absorptive capacity triad: a configurational study of individual, enabling, and motivating factors

    NARCIS (Netherlands)

    Löwik, Sandor Jan Albert; Kraaijenbrink, Jeroen; Groen, Arend J.

    2016-01-01

    Purpose The paper aims to understand how knowledge-intensive teams can develop and enhance their team absorptive capacity (ACAP) level, by exploring whether individual and organizational factors are complements or substitutes for team ACAP. Design/methodology/approach The study applies a

  18. Ultrafast X-ray absorption study of longitudinal-transverse phonon coupling in electrolyte aqueous solution

    DEFF Research Database (Denmark)

    Jiao, Yishuo; Adams, Bernhard W.; Dohn, Asmus Ougaard

    2017-01-01

    Ultrafast X-ray absorption spectroscopy is applied to study the conversion of longitudinal to transverse phonons in aqueous solution. Permanganate solutes serve as X-ray probe molecules that permit the measurement of the conversion of 13.5 GHz, longitudinal phonons to 27 GHz, transverse phonons...

  19. FDTD/TDSE study of surface-enhanced infrared absorption by metal nanoparticles.

    Energy Technology Data Exchange (ETDEWEB)

    Chang, S.-H.; Schatz, G. C.; Gray, S. K.; Chemistry; Northwestern Univ.; National Cheng-Kung Univ.

    2006-01-01

    We study surface-enhanced infrared absorption, including multiphoton processes, due to the excitation of surface plasmons on metal nanoparticles. The time-dependent Schroedinger equation and finite-difference time-domain method are self-consistently coupled to treat the problem.

  20. Study of an absorption machine for an ammonia-water system ...

    African Journals Online (AJOL)

    This paper deals with Study of an absorption machine for an ammonia-water system decentralized trigeneration. The effects of evaporator, absorber and boiler temperature on the coefficient of performance of this cycle investigate. Simulation results show that with increasing the evaporator and absorber temperature the ...

  1. The team absorptive capacity triad : a configurational study of individual, enabling, and motivating factors

    NARCIS (Netherlands)

    Lowik, Sandor; Kraaijenbrink, Jeroen; Groen, Aard

    2016-01-01

    Purpose - The paper aims to understand how knowledge-intensive teams can develop and enhance their team absorptive capacity (ACAP) level, by exploring whether individual and organizational factors are complements or substitutes for team ACAP. Design/methodology/approach - The study applies a

  2. Study of cancer cell lines with Fourier transform infrared (FTIR)/vibrational absorption (VA) spectroscopy

    DEFF Research Database (Denmark)

    Uceda Otero, E. P.; Eliel, G. S. N.; Fonseca, E. J. S.

    2013-01-01

    In this work we have used Fourier transform infrared (FTIR) / vibrational absorption (VA) spectroscopy to study two cancer cell lines: the Henrietta Lacks (HeLa) human cervix carcinoma and 5637 human bladder carcinoma cell lines. Our goal is to experimentally investigate biochemical changes...

  3. Absorption Refrigeration Cycles with Ammonia-Ionic Liquid Working Pairs Studied by Molecular Simulation

    NARCIS (Netherlands)

    Becker, T.M.; Wang, M.; Kabra, Abhishek; Jamali, S.H.; Ramdin, M.; Dubbeldam, D.; Infante Ferreira, C.A.; Vlugt, T.J.H.

    2018-01-01

    For absorption refrigeration, it has been shown that ionic liquids have the potential to replace conventional working pairs. Due to the huge number of possibilities, conducting lab experiments to find the optimal ionic liquid is infeasible. Here, we provide a proof-of-principle study of an

  4. High Pressure X-ray Absorption Studies on Correlated-Electron Systems

    International Nuclear Information System (INIS)

    Cornelius, Andrew L.

    2016-01-01

    This project used high pressure to alter the electron-electron and electron-lattice interactions in rare earth and actinide compounds. Knowledge of these properties is the starting points for a first-principles understanding of electronic and electronically related macroscopic properties. The research focused on a systematic study of x-ray absorption measurements on rare earth and actinide compounds.

  5. Results of Self-Absorption Study on the Versapor 3000 Filters for Radioactive Particulate Air Sampling

    International Nuclear Information System (INIS)

    Barnett, J.M.

    2008-01-01

    Since the mid-1980s the Pacific Northwest National Laboratory (PNNL) has used a value of 0.85 as a correction factor for the self absorption of activity of particulate radioactive air samples. More recently, an effort was made to evaluate the current particulate radioactive air sample filters (Versapor(reg s ign) 3000) used at PNNL for self absorption effects. There were two methods used in the study, (1) to compare the radioactivity concentration by direct gas-flow proportional counting of the filter to the results obtained after acid digestion of the filter and counting again by gas-flow proportional detection and (2) to evaluate sample filters by high resolution visual/infrared microscopy to determine the depth of material loading on or in the filter fiber material. Sixty samples were selected from the archive for acid digestion in the first method and about 30 samples were selected for high resolution visual/infrared microscopy. Mass loading effects were also considered. From the sample filter analysis, large error is associated with the average self absorption factor, however, when the data is compared directly one-to-one, statistically, there appears to be good correlation between the two analytical methods. The mass loading of filters evaluated was <0.2 mg cm-2 and was also compared against other published results. The microscopy analysis shows the sample material remains on the top of the filter paper and does not imbed into the filter media. Results of the microscopy evaluation lead to the conclusion that there is not a mechanism for significant self absorption. The overall conclusion is that self-absorption is not a significant factor in the analysis of filters used at PNNL for radioactive air stack sampling of radionuclide particulates and that an applied correction factor is conservative in determining overall sample activity. A new self absorption factor of 1.0 is recommended

  6. Excited state electron and energy relays in supramolecular dinuclear complexes revealed by ultrafast optical and X-ray transient absorption spectroscopy.

    Science.gov (United States)

    Hayes, Dugan; Kohler, Lars; Hadt, Ryan G; Zhang, Xiaoyi; Liu, Cunming; Mulfort, Karen L; Chen, Lin X

    2018-01-28

    The kinetics of photoinduced electron and energy transfer in a family of tetrapyridophenazine-bridged heteroleptic homo- and heterodinuclear copper(i) bis(phenanthroline)/ruthenium(ii) polypyridyl complexes were studied using ultrafast optical and multi-edge X-ray transient absorption spectroscopies. This work combines the synthesis of heterodinuclear Cu(i)-Ru(ii) analogs of the homodinuclear Cu(i)-Cu(i) targets with spectroscopic analysis and electronic structure calculations to first disentangle the dynamics at individual metal sites by taking advantage of the element and site specificity of X-ray absorption and theoretical methods. The excited state dynamical models developed for the heterodinuclear complexes are then applied to model the more challenging homodinuclear complexes. These results suggest that both intermetallic charge and energy transfer can be observed in an asymmetric dinuclear copper complex in which the ground state redox potentials of the copper sites are offset by only 310 meV. We also demonstrate the ability of several of these complexes to effectively and unidirectionally shuttle energy between different metal centers, a property that could be of great use in the design of broadly absorbing and multifunctional multimetallic photocatalysts. This work provides an important step toward developing both a fundamental conceptual picture and a practical experimental handle with which synthetic chemists, spectroscopists, and theoreticians may collaborate to engineer cheap and efficient photocatalytic materials capable of performing coulombically demanding chemical transformations.

  7. Electronic properties and optical absorption of graphene-polyvinylidene fluoride nanocomposites: A theoretical study

    Energy Technology Data Exchange (ETDEWEB)

    Chopra, Siddheshwar, E-mail: schopra1@amity.edu

    2017-01-15

    Graphene/polyvinylidene fluoride (graphene/PVDF) nanocomposites were studied using Density functional theory (DFT)/Time dependent density functional theory (TDDFT) calculations. Five nanocomposite configurations were constructed. Electronic properties like binding energy, electronic gap and work function were calculated. The most stable structure was determined. The electronic gap of graphene shifts from semiconducting to conducting, on nanocomposite formation. Workfunction of the most stable nanocomposite was 4.34eV ± 0.05eV, close to that of the pristine graphene (4.33eV ± 0.05eV). Thermochemical analysis showed that the adsorption is spontaneous above ∼870 K, and endothermic in nature. TDDFT calculations were performed for B3LYP, LSDA, BHHLYP and PBE0 functionals. B3LYP and PBE0 are suitable in describing optical absorption. Optical gap of graphene shrinks, and light absorption gets enhanced on nanocomposite formation. - Highlights: • Various properties of graphene-PVDF nanocomposites were studied theoretically. • Electronic gap of graphene shifts to conducting nature, on composite formation. • Adsorption is spontaneous above ∼870 K, and endothermic in nature. • B3LYP and PBE0 functionals are suitable in describing absorption. • Optical absorption gets enhanced on nanocomposite formation.

  8. Electronic properties and optical absorption of graphene-polyvinylidene fluoride nanocomposites: A theoretical study

    International Nuclear Information System (INIS)

    Chopra, Siddheshwar

    2017-01-01

    Graphene/polyvinylidene fluoride (graphene/PVDF) nanocomposites were studied using Density functional theory (DFT)/Time dependent density functional theory (TDDFT) calculations. Five nanocomposite configurations were constructed. Electronic properties like binding energy, electronic gap and work function were calculated. The most stable structure was determined. The electronic gap of graphene shifts from semiconducting to conducting, on nanocomposite formation. Workfunction of the most stable nanocomposite was 4.34eV ± 0.05eV, close to that of the pristine graphene (4.33eV ± 0.05eV). Thermochemical analysis showed that the adsorption is spontaneous above ∼870 K, and endothermic in nature. TDDFT calculations were performed for B3LYP, LSDA, BHHLYP and PBE0 functionals. B3LYP and PBE0 are suitable in describing optical absorption. Optical gap of graphene shrinks, and light absorption gets enhanced on nanocomposite formation. - Highlights: • Various properties of graphene-PVDF nanocomposites were studied theoretically. • Electronic gap of graphene shifts to conducting nature, on composite formation. • Adsorption is spontaneous above ∼870 K, and endothermic in nature. • B3LYP and PBE0 functionals are suitable in describing absorption. • Optical absorption gets enhanced on nanocomposite formation.

  9. Kinetic study of carbon dioxide absorption into glycine promoted diethanolamine (DEA)

    Science.gov (United States)

    Pudjiastuti, Lily; Susianto, Altway, Ali; IC, Maria Hestia; Arsi, Kartika

    2015-12-01

    In industry, especially petrochemical, oil and natural gas industry, required separation process of CO2 gas which is a corrosive gas (acid gas). This characteristic can damage the plant utility and piping systems as well as reducing the caloric value of natural gas. Corrosive characteristic of CO2 will appear in areas where there is a decrease in temperature and pressure, such as at the elbow pipe, tubing, cooler and injector turbine. From disadvantages as described above, then it is important to do separation process in the CO2 gas stream, one of the method for remove CO2 from the gas stream is reactive absorption using alkanolamine based solution with promotor. Therefore, this study is done to determine the kinetics constant of CO2 absorption in diethanolamine (DEA) solution using a glycine promoter. Glycine is chosen as a promoter because glycine is a primary amine compound which is reactive, moreover, glycine has resistance to high temperatures so it will not easy to degradable and suitable for application in industry. The method used in this study is absorption using laboratory scale wetted wall column equipment at atmospheric of pressure. This study will to provide the reaction kinetics data information in order to optimize the separation process of CO2 in the industrialized world. The experimental results show that rising temperatures from 303,15 - 328,15 K and the increase of concentration of glycine from 1% - 3% weight will increase the absorption rate of carbon dioxide in DEA promoted with glycine by 24,2% and 59,764% respectively, also the reaction kinetic constant is 1.419 × 1012 exp (-3634/T) (m3/kmol.s). This result show that the addition of glycine as a promoter can increase absorption rate of carbon dioxide in diethanolamine solution and cover the weaknesses of diethanolamine solution.

  10. A theoretical and experimental study of calcium, iron, zinc, cadmium, and sodium ions absorption by aspartame.

    Science.gov (United States)

    Mahnam, Karim; Raisi, Fatame

    2017-03-01

    Aspartame (L-Aspartyl-L-phenylalanine methyl ester) is a sweet dipeptide used in some foods and beverages. Experimental studies show that aspartame causes osteoporosis and some illnesses, which are similar to those of copper and calcium deficiency. This raises the issue that aspartame in food may interact with cations and excrete them from the body. This study aimed to study aspartame interaction with calcium, zinc, iron, sodium, and cadmium ions via molecular dynamics simulation (MD) and spectroscopy. Following a 480-ns molecular dynamics simulation, it became clear that the aspartame is able to sequester Fe 2+ , Ca 2+ , Cd 2+ , and Zn 2+ ions for a long time. Complexation led to increasing UV-Vis absorption spectra and emission spectra of the complexes. This study suggests a potential risk of cationic absorption of aspartame. This study suggests that purification of cadmium-polluted water by aspartame needs a more general risk assessment.

  11. Study on Relative COP Changes with Increasing Heat Input Temperatures of Double Effect Steam Absorption Chillers

    Directory of Open Access Journals (Sweden)

    Abd Majid Mohd Amin

    2016-01-01

    Full Text Available Absorption chillers at cogeneration plants generate chilled water using steam supplied by heat recovery steam generators. The chillers are mainly of double effect type. The COP of double effect varies from 0.7 to 1.2 depending on operation and maintenance practices of the chillers. Heat input to the chillers during operations could have impact on the COP of the chillers. This study is on relative COP changes with increasing the heat input temperatures for a steam absorption chiller at a gas fueled cogeneration plant. Reversible COP analysis and zero order model were used for evaluating COP of the chiller for 118 days operation period. Results indicate increasing COP trends for both the reversible COP and zero model COP. Although the zero model COP are within the range of double effect absorption chiller, it is not so for the actual COP. The actual COP is below the range of normal double effect COP. It is recommended that economic replacement analysis to be undertaken to assess the feasibility either to repair or replace the existing absorption chiller.

  12. Study on the prediction of visible absorption maxima of azobenzene compounds

    Science.gov (United States)

    Liu, Jun-na; Chen, Zhi-rong; Yuan, Shen-feng

    2005-01-01

    The geometries of azobenzene compounds are optimized with B3LYP/6-311G* method, and analyzed with nature bond orbital, then their visible absorption maxima are calculated with TD-DFT method and ZINDO/S method respectively. The results agree well with the observed values. It was found that for the calculation of visible absorption using ZINDO/S method could rapidly yield better results by adjusting OWFπ-π (the relationship between π-π overlap weighting factor) value than by the TD-DFT method. The method of regression showing the linear relationship between OWFπ-π and BLN-N (nitrogen-nitrogen bond lengths) as OWF π-π=−8.1537+6.5638BL N-N, can be explained in terms of quantum theory, and also be used for prediction of visible absorption maxima of other azobenzne dyes in the same series. This study on molecules’ orbital geometry indicates that their visible absorption maxima correspond to the electron transition from HOMO (the highest occupied molecular orbital) to LUMO (the lowest unoccupied molecular orbital). PMID:15909349

  13. Absorption Refrigeration Cycles with Ammonia-Ionic Liquid Working Pairs Studied by Molecular Simulation.

    Science.gov (United States)

    Becker, Tim M; Wang, Meng; Kabra, Abhishek; Jamali, Seyed Hossein; Ramdin, Mahinder; Dubbeldam, David; Infante Ferreira, Carlos A; Vlugt, Thijs J H

    2018-04-18

    For absorption refrigeration, it has been shown that ionic liquids have the potential to replace conventional working pairs. Due to the huge number of possibilities, conducting lab experiments to find the optimal ionic liquid is infeasible. Here, we provide a proof-of-principle study of an alternative computational approach. The required thermodynamic properties, i.e., solubility, heat capacity, and heat of absorption, are determined via molecular simulations. These properties are used in a model of the absorption refrigeration cycle to estimate the circulation ratio and the coefficient of performance. We selected two ionic liquids as absorbents: [emim][Tf 2 N], and [emim][SCN]. As refrigerant NH 3 was chosen due to its favorable operating range. The results are compared to the traditional approach in which parameters of a thermodynamic model are fitted to reproduce experimental data. The work shows that simulations can be used to predict the required thermodynamic properties to estimate the performance of absorption refrigeration cycles. However, high-quality force fields are required to accurately predict the cycle performance.

  14. Absorption Refrigeration Cycles with Ammonia–Ionic Liquid Working Pairs Studied by Molecular Simulation

    Science.gov (United States)

    2018-01-01

    For absorption refrigeration, it has been shown that ionic liquids have the potential to replace conventional working pairs. Due to the huge number of possibilities, conducting lab experiments to find the optimal ionic liquid is infeasible. Here, we provide a proof-of-principle study of an alternative computational approach. The required thermodynamic properties, i.e., solubility, heat capacity, and heat of absorption, are determined via molecular simulations. These properties are used in a model of the absorption refrigeration cycle to estimate the circulation ratio and the coefficient of performance. We selected two ionic liquids as absorbents: [emim][Tf2N], and [emim][SCN]. As refrigerant NH3 was chosen due to its favorable operating range. The results are compared to the traditional approach in which parameters of a thermodynamic model are fitted to reproduce experimental data. The work shows that simulations can be used to predict the required thermodynamic properties to estimate the performance of absorption refrigeration cycles. However, high-quality force fields are required to accurately predict the cycle performance. PMID:29749996

  15. Landmark Study Reveals Antarctic Glacier's Long History of Retreat

    OpenAIRE

    Kuska, Dale M.

    2016-01-01

    Faculty Showcase Archive Article Approved for public release; distribution is unlimited. A major study, released in late November in the journal “Nature,” reveals the history of retreat of the massive Pine Island Glacier (PIG) in western Antarctica, widely considered one of the largest contributors to global sea-level rise.

  16. Comparative study of the tests of fat absorption using triolein or oleic acid labelled with 131I and 14C

    International Nuclear Information System (INIS)

    Grenier, J.F.; Dauchel, J.; Eloy, M.R.; Mendel, C.; Privat, J.P.

    1976-01-01

    Studies of the absorption of radioiodinated fats introduced into the lumen of isolated intestinal loops of dogs have shown that these compounds are promptly and to a large extent dehalogenated, not only in the small bowel, but also in the colon. Further comparative experimental studies on dogs and patients, using 14 C-labelled fats, have demonstrated that the absorption of the mineral 131 I and of the fats is not simultaneous. Therefore, the use of triolein labelled with 131 I to measure fat absorption should be abandoned. However, it is concluded that tests of intestinal absorption using 14 C-labelled triolein are of great interest. (author)

  17. Theoretical study of electronic absorption spectroscopy of propadienylidene molecule vis-â-vis the observed diffuse interstellar bands

    International Nuclear Information System (INIS)

    Reddy, Samala Nagaprasad; Mahapatra, S.

    2012-01-01

    Highlights: ► Theoretical study of spectroscopy and dynamics of electronically excited l-C 3 H 2 . ► Construction of ab initio electronic potential energy and diabatic coupling surfaces. ► First principles study of nuclear dynamics on excited electronic states. ► Findings reveal l-C 3 H 2 is a potential molecular carrier of diffuse interstellar bands. ► Electronically excited l-C 3 H 2 decays by ultrafast nonradiative internal conversion. -- Abstract: Observation of broad and diffuse interstellar bands (DIBs) at 4881 Å and 5440 Å assigned to the optical absorption spectrum of Y-shaped propadienylidene (H 2 C=C=C:) molecule is theoretically examined in this paper. This molecule apparently absorbs in the same wavelength region as the observed DIBs and was suggested to be a potential carrier of these DIBs. This assignment mostly relied on the experimental data from radioastronomy and laboratory measurements. Motivated by these available experimental data we attempt here a theoretical study and investigate the detailed electronic structure and nuclear dynamics underlying the electronic absorption bands of propadienylidene molecule. Our results show that this molecule indeed absorbs in the wavelength region of the recorded DIBs. Strong nonadiabatic coupling between its energetically low-lying electronic states plays major role, initiates ultrafast internal conversion and contributes to the spectral broadening. Theoretical findings are finally compared with the available experimental and theoretical data and discussed in connection with the recorded DIBs.

  18. Study of nonlinear optical absorption properties of V{sub 2}O{sub 5} nanoparticles in the femtosecond excitation regime

    Energy Technology Data Exchange (ETDEWEB)

    Molli, Muralikrishna; Bhat Kademane, Abhijit; Pradhan, Prabin; Sai Muthukumar, V. [Sri Sathya Sai Institute of Higher Learning, Department of Physics, Puttaparthi, Andhra Pradesh (India)

    2016-08-15

    In this work, we report for the first time, the nonlinear optical absorption properties of vanadium pentoxide (V{sub 2}O{sub 5}) nanoparticles in the femtosecond excitation regime. V{sub 2}O{sub 5} nanoparticles were synthesized through solution combustion technique. The as-synthesized samples were further characterized using XRD, FESEM, EDAX, TEM and UV-visible spectroscopy. X-ray diffraction results revealed the crystalline nature of the nanoparticles. Electron microscopy studies showed the size of the nanoparticles to be ∝200 nm. Open-aperture z-scan technique was employed to study the nonlinear optical absorption behavior of the synthesized samples using a 100-fs laser pulses at 800 nm from a regeneratively amplified Ti: sapphire laser. The mechanism of nonlinear absorption was found to be a three-photon absorption process which was explained using the density of states of V{sub 2}O{sub 5} obtained using density functional theory. These nanoparticles exhibit strong intensity-dependent nonlinear optical absorption and hence could be considered for optical-power-limiting applications. (orig.)

  19. Intrinsic and extrinsic labeling for studies of manganese absorption in humans

    International Nuclear Information System (INIS)

    Davidsson, L.; Cederblad, A.; Hagebo, E.; Loennerdal, B.S.; Sandstroem, B.

    1988-01-01

    A dual-radioisotope method was used to simultaneously study whole-body manganese retention from a chicken liver based meal intrinsically labeled with 54 Mn and extrinsically labeled with 52 Mn. Manganese retention was monitored in a sensitive whole-body counter during approximately 30 d in six young adult women. Both radioisotopes were retained to a similar degree and excreted at identical rates. Retention at d 5 was 14.4 +/- 10.3 and 14.0 +/- 9.9% while retention at d 10 was 5.0 +/- 3.1 and 5.0 +/- 3.0% (X +/- SD) for 54 Mn and 52 Mn, respectively. From these results we conclude that the intrinsic and extrinsic Mn isotopes did form a common pool before absorption. The results can therefore be regarded as a direct validation of the use of extrinsic labeling for studies of Mn retention for estimating Mn absorption in man

  20. Autoradiographic study on percutaneous absorption of several oils useful for cosmetics

    International Nuclear Information System (INIS)

    Suzuki, M.; Asaba, K.; Komatsu, H.; Mochizuka, M.

    1978-01-01

    Percutaneous absorption of five 14 C-labelled oils, n-octadecane, decanoxy decane, 2-hexyldecanoxy octane, isopropyl myristate and glyceryl tri-(oleate), commonly used is cosmetics were studied from the point of view of their safety. In whole body autoradiography of hairless mice, there was no visible penetration into the skin and organs, whereas microautoradiography of guinea pigs showed local penetration. Isopropyl myristate penetrated to the greatest extent, whereas 2-hexyldecanoxy octane was hardly absorbed. Percutaneous absorption of these two oils, therefore, was examined in Angora rabbits by microautoradiography simultaneously with skin irritation potential by a histological method, from the following aspects, (1) patterns of penetration and irritation in relation to application time and (2) fate within the skin and pattern of irritation after application. In addition, intradermal metabolic fate was studied in vivo. (author)

  1. Optical Absorption and Electron Injection of 4-(Cyanomethylbenzoic Acid Based Dyes: A DFT Study

    Directory of Open Access Journals (Sweden)

    Yuehua Zhang

    2015-01-01

    Full Text Available Density functional theory (DFT and time-dependent density functional theory (TDDFT calculations were carried out to study the ground state geometries, electronic structures, and absorption spectra of 4-(cyanomethylbenzoic acid based dyes (AG1 and AG2 used for dye-sensitized solar cells (DSSCs. The excited states properties and the thermodynamical parameters of electron injection were studied. The results showed that (a two dyes have uncoplanar structures along the donor unit and conjugated bridge space, (b two sensitizers exhibited intense absorption in the UV-Vis region, and (c the excited state oxidation potential was higher than the conduction band edge of TiO2 photoanode. As a result, a solar cell based on the 4-(cyanomethylbenzoic acid based dyes exhibited well photovoltaic performance. Furthermore, nine dyes were designed on the basis of AG1 and AG2 to improve optical response and electron injection.

  2. Application of Polarization Modulated Infrared Reflection Absorption Spectroscopy for electrocatalytic activity studies of laccase adsorbed on modified gold electrodes

    International Nuclear Information System (INIS)

    Olejnik, Piotr; Pawłowska, Aleksandra; Pałys, Barbara

    2013-01-01

    Orientation of the enzyme macromolecule on the electrode surface is crucially important for the efficiency of the electron transport between the active site and electrode surface. The orientation can be controlled by affecting the surface charge and the pH of the buffer solution. In this contribution we study laccase physically adsorbed on gold surface modified by mercapto-ethanol, lipid and variously charged diazonium salts. Polarization Modulated Infrared Reflection Absorption Spectroscopy (PMIRRAS) enables the molecular orientation study of the protein molecule by comparison of the amide I to amide II band intensity ratios assuming that the protein secondary structure does not change. We observe significant differences in the intensity ratios depending on the kind of support and the enzyme deposition. The comparison of infrared spectra and cyclic voltammetry responses of variously prepared laccase layers reveals that the parallel orientation of beta-sheet moieties results in high enzyme activity

  3. Absorption and fluorescence studies of curcumin bound to liposomes and lymphocytes: effect of {gamma}- irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kunwar, Amit; Barik, A; Indira Priyadarsini, K [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai (India); Pandey, R [Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Mumbai (India)

    2006-01-15

    Absorption and fluorescence spectral changes in curcumin were employed to follow its binding to liposomes and lymphocytes. The association constants indicated high affinity of curcumin to liposomes. Tumor lymphocytes show mere intense fluorescence of curcumin over the normal lymphocytes. The loss of curcumin in cells after {gamma}-irradiation could be followed by reduction in curcumin fluorescence. The studies indicate that such fluorescence changes can be used as markers to understand the preferential loading of curcumin to cells. (author)

  4. Absorption and fluorescence studies of curcumin bound to liposomes and lymphocytes: effect of γ- irradiation

    International Nuclear Information System (INIS)

    Kunwar, Amit; Barik, A.; Indira Priyadarsini, K.; Pandey, R.

    2006-01-01

    Absorption and fluorescence spectral changes in curcumin were employed to follow its binding to liposomes and lymphocytes. The association constants indicated high affinity of curcumin to liposomes. Tumor lymphocytes show mere intense fluorescence of curcumin over the normal lymphocytes. The loss of curcumin in cells after γ-irradiation could be followed by reduction in curcumin fluorescence. The studies indicate that such fluorescence changes can be used as markers to understand the preferential loading of curcumin to cells. (author)

  5. Atomic structure of machined semiconducting chips: An x-ray absorption spectroscopy study

    Energy Technology Data Exchange (ETDEWEB)

    Paesler, M.; Sayers, D.

    1988-12-01

    X-ray absorption spectroscopy (XAS) has been used to examine the atomic structure of chips of germanium that were produced by single point diamond machining. It is demonstrated that although the local (nearest neighbor) atomic structure is experimentally quite similar to that of single crystal specimens information from more distant atoms indicates the presence of considerable stress. An outline of the technique is given and the strength of XAS in studying the machining process is demonstrated.

  6. Transient absorption studies in pure rare gases from 2500 A to 4000 A

    Energy Technology Data Exchange (ETDEWEB)

    Champagne, L F; Chang, R S.F. [Naval Research Lab., Washington, DC (USA)

    1980-01-01

    The broad band absorption in electron beam excited rare gas plasmas was measured for neon, argon, krypton and xenon gas. A broad continuum emission from a xenon flashlamp was used as the probe source. Absorption data was obtained over a 1500 A range. Absorption peaks in argon, neon and xenon correlate well with the predicted peak absorption cross sections for the respective dimer ions. No absorption peak in krypton was observed. Secondary absorption peaks of comparable magnitude to the dimer absorption peak were also observed in argon and xenon.

  7. Subcutaneous insulin absorption explained by insulin's physicochemical properties. Evidence from absorption studies of soluble human insulin and insulin analogues in humans.

    Science.gov (United States)

    Kang, S; Brange, J; Burch, A; Vølund, A; Owens, D R

    1991-11-01

    To study the influence of molecular aggregation on rates of subcutaneous insulin absorption and to attempt to elucidate the mechanism of absorption of conventional soluble human insulin in humans. Seven healthy male volunteers aged 22-43 yr and not receiving any drugs comprised the study. This study consisted of a single-blind randomized comparison of equimolar dosages of 125I-labeled forms of soluble hexameric 2 Zn2+ human insulin and human insulin analogues with differing association states at pharmaceutical concentrations (AspB10, dimeric; AspB28, mixture of monomers and dimers; AspB9, GluB27, monomeric). After an overnight fast and a basal period of 1 h, 0.6 nmol/kg of either 125I-labeled human soluble insulin (Actrapid HM U-100) or 125I-labeled analogue was injected subcutaneously on 4 separate days 1 wk apart. Absorption was assessed by measurement of residual radioactivity at the injection site by external gamma-counting. The mean +/- SE initial fractional disappearance rates for the four preparations were 20.7 +/- 1.9 (hexameric soluble human insulin), 44.4 +/- 2.5 (dimeric analogue AspB10), 50.6 +/- 3.9 (analogue AspB28), and 67.4 +/- 7.4%/h (monomeric analogue AspB9, GluB27). Absorption of the dimeric analogue was significantly faster than that of hexameric human insulin (P less than 0.001); absorption of monomeric insulin analogue AspB9, GluB27 was significantly faster than that of dimeric analogue AspB10 (P less than 0.01). There was an inverse linear correlation between association state and the initial fractional disappearance rates (r = -0.98, P less than 0.02). Analysis of the disappearance data on a log linear scale showed that only the monomeric analogue had a monoexponential course throughout. Two phases in the rates of absorption were identified for the dimer and three for hexameric human insulin. The fractional disappearance rates (%/h) calculated by log linear regression analysis were monomer 73.3 +/- 6.8; dimer 44.4 +/- 2.5 from 0 to 2 h and

  8. Review of Russian language studies on radionuclide behaviour in agricultural animals: part 1. Gut absorption.

    Science.gov (United States)

    Fesenko, S; Isamov, N; Howard, B J; Voigt, G; Beresford, N A; Sanzharova, N

    2007-01-01

    An extensive programme of experiments was conducted in the former USSR on transfer of radionuclides to a wide range of different agricultural animals. Only a few of these studies were made available in the English language literature or taken into account in international reviews of gastrointestinal uptake. The paper gives extended information on Russian research on radionuclide absorption in the gut of farm animals performed in controlled field and laboratory experiments from the 1960s to the current time. The data presented in the paper, together with English language values, will be used to provide recommended values of absorption specifically for farm animals within the revision of the IAEA Handbook of Parameter Values IAEA [International Atomic Energy Agency, 1994. Handbook of Parameter Values for the Prediction of Radionuclide Transfer in Temperate Environments, IAEA technical reports series No. 364. International Atomic Energy Agency, Vienna].

  9. X-ray absorption near-edge spectroscopic study of nickel catalysts

    International Nuclear Information System (INIS)

    Soldatov, Alexander V.; Smolentsev, Grigory; Kravtsova, Antonina; Yalovega, Galina; Feiters, Martin C.; Metselaar, Gerald A.; Joly, Yves

    2006-01-01

    Ni-isocyanide and Ni-acac complexes have been studied by X-ray absorption spectroscopy. Theoretical analysis has been done using self-consistent full multiple scattering (MS) approach within both muffin-tin (MT) model of the potential and non-MT finite deference method. For the isocyanide complex, it was shown that MS theoretical spectra reproduce all structural details of the X-ray absorption near-edge structure (XANES), but also that it is important to consider the non-MT effects in the potential for a correct simulation of the shape of the pre-edge structures. The contribution of a non-constant potential in the interstitial regions is extremely important for the interpretation of the XANES of Ni(acac) 2

  10. Review of Russian language studies on radionuclide behaviour in agricultural animals: part 1. Gut absorption

    International Nuclear Information System (INIS)

    Fesenko, S.; Isamov, N.; Howard, B.J.; Voigt, G.; Beresford, N.A.; Sanzharova, N.

    2007-01-01

    An extensive programme of experiments was conducted in the former USSR on transfer of radionuclides to a wide range of different agricultural animals. Only a few of these studies were made available in the English language literature or taken into account in international reviews of gastrointestinal uptake. The paper gives extended information on Russian research on radionuclide absorption in the gut of farm animals performed in controlled field and laboratory experiments from the 1960s to the current time. The data presented in the paper, together with English language values, will be used to provide recommended values of absorption specifically for farm animals within the revision of the IAEA Handbook of Parameter Values IAEA [International Atomic Energy Agency, 1994. Handbook of Parameter Values for the Prediction of Radionuclide Transfer in Temperate Environments, IAEA technical reports series No. 364. International Atomic Energy Agency, Vienna

  11. X-ray absorption spectroscopic studies of mononuclear non-heme iron enzymes

    Energy Technology Data Exchange (ETDEWEB)

    Westre, Tami E. [Stanford Univ., CA (United States)

    1996-01-01

    Fe-K-edge X-ray absorption spectroscopy (XAS) has been used to investigate the electronic and geometric structure of the iron active site in non-heme iron enzymes. A new theoretical extended X-ray absorption fine structure (EXAFS) analysis approach, called GNXAS, has been tested on data for iron model complexes to evaluate the utility and reliability of this new technique, especially with respect to the effects of multiple-scattering. In addition, a detailed analysis of the 1s→3d pre-edge feature has been developed as a tool for investigating the oxidation state, spin state, and geometry of iron sites. Edge and EXAFS analyses have then been applied to the study of non-heme iron enzyme active sites.

  12. A polarizable embedding DFT study of one-photon absorption in fluorescent proteins

    DEFF Research Database (Denmark)

    Beerepoot, Maarten; Steindal, Arnfinn H.; Kongsted, Jacob

    2013-01-01

    mutants (BFP, eGFP, YFP and eCFP). The observed trends in excitation energies among the FPs are reproduced by our approach when performing calculations directly on the crystal structures or when using structures extracted from a molecular dynamics simulations. However, in the former case, QM/MM geometry......A theoretical study of the one-photon absorption of five fluorescent proteins (FPs) is presented. The absorption properties are calculated using a polarizable embedding approach combined with density functional theory (PE-DFT) on the wild-type green fluorescent protein (wtGFP) and several of its...... optimization of the chromophores within a frozen protein environment is needed in order to reproduce the experimental trends. Explicit account of polarization in the force field is not needed to yield the correct trend between the different FPs, but is necessary for reproducing the experimentally observed red...

  13. Emission and absorption spectroscopy study of Ar excited states in 13.56 MHz argon plasma operating at sub-atmospheric to atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Li, L. [Department of Applied Physics, Research Unit Plasma Technology, Ghent University, Jozef Plateaustraat 22, Ghent B-9000 (Belgium); Nikiforov, A., E-mail: anton.nikiforov@ugent.be [Department of Applied Physics, Research Unit Plasma Technology, Ghent University, Jozef Plateaustraat 22, Ghent B-9000 (Belgium); Institute of Solution Chemistry of the Russian Academy of Science, Academicheskaya St., 1, Ivanovo, 153045 (Russian Federation); Britun, N. [Chimie des Interactions Plasma-Surface (ChIPS), CIRMAP, Universite de Mons, 23 Place du Parc, B-7000 Mons (Belgium); Snyders, R. [Chimie des Interactions Plasma-Surface (ChIPS), CIRMAP, Universite de Mons, 23 Place du Parc, B-7000 Mons (Belgium); Materia Nova Research Centre, Parc Initialis, B-7000 Mons (Belgium); Leys, C. [Department of Applied Physics, Research Unit Plasma Technology, Ghent University, Jozef Plateaustraat 22, Ghent B-9000 (Belgium)

    2015-05-01

    The densities of metastable and resonant states of Ar atoms are measured in high pressure Ar radio frequency discharge. Resonant absorption spectroscopy for the case of a low pressure spectral lamp and high-pressure plasma absorption lines is implemented for this purpose. The necessary generalizations for the high-pressure resonant absorption method are given. Absolute density of Ar 1s levels obtained at different RF input power and operating pressures are of the order of 10{sup 11} cm{sup −3}, which is in a good agreement with those reported in the literature. The population distribution on the Ar 2p (excited) levels, obtained from the optical emission spectroscopy, reveals strong deviation from thermal equilibrium for these levels in the high-pressure case. The generation of the Ar excited states in the studied discharges is compared to the previously reported results. - Highlights: • Strong non-equilibrium distribution of Ar 2p levels is observed. • The absolute number density of non-radiative Ar 1s states is determined by the easier and low cost spectral-lamp absorption method. • The modified absorption theory of Mitchell and Zemanski was used to obtain the absolute number density of Ar 1s states at high pressure. • The developed RF source with 5 cm long gap can be a possible alternative to micro-plasma working in Ar at atmospheric pressure.

  14. Sound attenuation and absorption by anisotropic fibrous materials: Theoretical and experimental study

    Science.gov (United States)

    Bravo, Teresa; Maury, Cédric

    2018-03-01

    This paper describes analytical and experimental studies carried out to examine the attenuation and absorption properties of rigidly-backed fibrous anisotropic materials in contact with a uniform mean flow. The aim is to provide insights for the development of non-locally reacting wall-treatments able to dissipate the noise induced by acoustic excitations over in-duct or external lining systems. A model of sound propagation in anisotropic bulk-reacting liners is presented that fully accounts for anisotropic losses due to heat conduction, viscous dissipation and diffusion processes along and across the material fibres as well as for the convective effect of an external flow. The propagation constant for the least attenuated mode of the coupled system is obtained using a simulated annealing search method. The predicted acoustical performance is validated in the no-flow case for a wide range of fibre diameters. They are assessed against impedance tube and free-field pressure-velocity measurements of the normal incidence absorption coefficient and surface impedance. Parametric studies are then conducted to determine the key constitutive parameters such as the fibres orientation or the amount of anisotropy that mostly influence the axial attenuation or the normal absorption. They are supported by a low-frequency approximation to the axial attenuation under a low-speed flow.

  15. Comparison of Flurbiprofen Tablets Available In Pakistani Market and Their Absorption Studies

    Directory of Open Access Journals (Sweden)

    Muhammad Hanif

    2015-06-01

    Full Text Available AbstractThe aim of this present work was to compare different parameters of various brands of flurbiprofen tablets collected from different retail pharmacies in the local market of Pakistan. Four brands A, B, C and D were tested for weight variation, hardness, friability, disintegration dissolution, HPLC assay and in vitro absorption studies in rabbit skin, stomach and intestine by using the prepacked Column RT 250-4.6 Purospher® STAR RP-18 end capped (5 µm and acetonitrile, phosphate buffer (pH 3.7 as mobile phase in the ratio of 1:1. Flurbiprofen was detected at 265 nm at the flow rate of 1 ml/min. Brand B was considered as reference. Similarity factor (f2 of brand B and C and brand B & D was found to be 61 and 51 and dissimilarity factors (f1 values were 5 and 9 respectively in same dissolution medium. Model dependent methods First order, Hixon crowell and Weibull model were used. The method was found to be sensitive and linear in the range of 10 to 700 ppm with 0.999 coefficient of correlation. Everted sac absorption studies of selected formulation showed 50% of drug absorption from stomach in first 3 hours, 21% through intestine and very negligible through skin.

  16. [Biopharmaceutics classification and absorption mechanisms primary study on four kinds of flavonoids].

    Science.gov (United States)

    Li, Hui-Fang; Zhang, Dong; Qu, Wen-Jun; Wang, Hai-Lin; Liu, Yang; Borjigdai, Almaz; Cui, Jian; Dong, Zheng-Qi

    2016-04-01

    The solubility and permeability on four kinds of flavonoids (kaempferol, hesperidin, apigenin, genistein) were test according to the theory of biopharmaceutics classification system (BCS), and their absorption mechanism. The solubility was investigated by the method in determination of solubility of "Chinese Pharmacopoeia 2010". To detect appearance permeability of compounds mentioned above, the appropriate concentrations were selected by the MTT method in cell transfer experiments in Caco-2 cell model, which established by in vitro cell culture method. Therefore, these compounds were classified with BCS according to solubility and permeability. In addition, to explore absorption mechanisms, the experiments in three different concentrations of compounds in high, medium and low in bidirectional transformation methods in Caco-2 cell model contacted. The study indicated that all of kaempferol, hesperidin, apigenin, genistein have the characteristics in low solubility and high permeability, which belong to BCSⅡ, and the absorption mechanism of kaempferol was active transportation. Whereas, hesperidin, apigenin, genistein were passive transportation. In this study, it carried out initial explorations on establishment of determination for solubility and permeability in flavonoids, and provided theoretical reference for further research on BCS in traditional Chinese medicine. Copyright© by the Chinese Pharmaceutical Association.

  17. In vitro predictions of skin absorption of caffeine, testosterone, and benzoic acid: A multi-centre comparison study

    NARCIS (Netherlands)

    Sandt, J.J.M. van de; Burgsteden, J.A. van; Cage, S.; Carmichael, P.L.; Dick, I.; Kenyon, S.; Korinth, G.; Larese, F.; Limasset, J.C.; Maas, W.J.M.; Montomoli, L.; Nielsen, J.B.; Payan, J.-P.; Robinson, E.; Sartorelli, P.; Schaller, K.H.; Wilkinson, S.C.; Williams, F.M.

    2004-01-01

    To obtain better insight into the robustness of in vitro percutaneous absorption methodology, the intra- and inter-laboratory variation in this type of study was investigated in 10 European laboratories. To this purpose, the in vitro absorption of three compounds through human skin (9 laboratories)

  18. Formation Mechanism of Ge Nanocrystals Embedded in SiO2 Studied by Fluorescence X-Ray Absorption Fine Structure

    International Nuclear Information System (INIS)

    Yan Wensheng; Li Zhongrui; Sun Zhihu; Wei Shiqiang; Kolobov, A. V.

    2007-01-01

    The formation mechanism of Ge nanocrystals for Ge (60 mol%) embedded in a SiO2 matrix grown on Si(001) and quartz-glass substrates was studied by fluorescence x-ray absorption fine structure (XAFS). It was found that the formation of Ge nanocrystals strongly depends on the properties of the substrate materials. In the as-prepared samples, Ge atoms exist in amorphous Ge and GeO2 phases. At the annealing temperature of 1073 K, on the quartz-glass substrate, Ge nanocrystals are only formed predominantly from the amorphous Ge phase in the as-prepared sample. However, on the Si(100) substrate the Ge nanocrystals are generated partly from amorphous Ge, and partly from GeO2 phases through the permutation reaction with Si substrate. Quantitative analysis revealed that about 10% of GeO2 in as-prepared sample permutated with Si in the wafer and formed Ge nanocrystals

  19. The Role of Water Distribution Controlled by Transmembrane Potentials in the Cytochrome c-Cardiolipin Interaction: Revealing from Surface-Enhanced Infrared Absorption Spectroscopy.

    Science.gov (United States)

    Zeng, Li; Wu, Lie; Liu, Li; Jiang, Xiue

    2017-11-02

    The interaction of cytochrome c (cyt c) with cardiolipin (CL) plays a crucial role in apoptotic functions, however, the changes of the transmembrane potential in governing the protein behavior at the membrane-water interface have not been studied due to the difficulties in simultaneously monitoring the interaction and regulating the electric field. Herein, surface-enhanced infrared absorption (SEIRA) spectroelectrochemistry is employed to study the mechanism of how the transmembrane potentials control the interaction of cyt c with CL membranes by regulating the electrode potentials of an Au film. When the transmembrane potential decreases, the water content at the interface of the membranes can be increased to slow down protein adsorption through decreasing the hydrogen-bond and hydrophobic interactions, but regulates the redox behavior of CL-bound cyt c through a possible water-facilitated proton-coupled electron transfer process. Our results suggest that the potential drop-induced restructure of the CL conformation and the hydration state could modify the structure and function of CL-bound cyt c on the lipid membrane. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Incorporation of Trace Elements in Ancient and Modern Human Bone: An X-Ray Absorption Spectroscopy Study

    Science.gov (United States)

    Pingitore, N. E.; Cruz-Jimenez, G.; Price, T. D.

    2001-12-01

    X-ray absorption spectroscopy (XAS) affords the opportunity to probe the atomic environment of trace elements in human bone. We are using XAS to investigate the mode(s) of incorporation of Sr, Zn, Pb, and Ba in both modern and ancient (and thus possibly altered) human and animal bone. Because burial and diagenesis may add trace elements to bone, we performed XAS analysis on samples of pristine contemporary and ancient, buried human and animal bone. We assume that deposition of these elements during burial occurs by processes distinct from those in vivo, and this will be reflected in their atomic environments. Archaeologists measure strontium in human and animal bone as a guide to diet. Carnivores show lower Sr/Ca ratios than their herbivore prey due to discrimination against Sr relative to Ca up the food chain. In an initial sample suite no difference was observed between modern and buried bone. Analysis of additional buried samples, using a more sensitive detector, revealed significant differences in the distance to the second and third neighbors of the Sr in some of the buried samples. Distances to the first neighbor, oxygen, were similar in all samples. Zinc is also used in paleo-diet studies. Initial x-ray absorption spectroscopy of a limited suite of bones did not reveal any differences between modern and buried samples. This may reflect the limited number of samples examined or the low levels of Zn in typical aqueous solutions in soils. Signals from barium and lead were too low to record useful XAS spectra. Additional samples will be studied for Zn, Ba, and Pb. We conducted our XAS experiments on beam lines 4-1 and 4-3 at the Stanford Synchrotron Radiation Laboratory. Data were collected in the fluorescence mode, using a Lytle detector and appropriate filter, and a solid state, 13-element Ge-detector.

  1. [Experimental study and correction of the absorption and enhancement effect between Ti, V and Fe].

    Science.gov (United States)

    Tuo, Xian-Guo; Mu, Ke-Liang; Li, Zhe; Wang, Hong-Hui; Luo, Hui; Yang, Jian-Bo

    2009-11-01

    The absorption and enhancement effects in X-ray fluorescence analysis for Ti, V and Fe elements were studied in the present paper. Three bogus duality systems of Ti-V/Ti-Fe/V-Fe samples were confected and measured by X-ray fluorescence analysis technique using HPGe semiconductor detector, and the relation curve between unitary coefficient (R(K)) of element count rate and element content (W(K)) were obtained after the experiment. Having analyzed the degree of absorption and enhancement effect between every two elements, the authors get the result, and that is the absorption and enhancement effect between Ti and V is relatively distinctness, while it's not so distinctness in Ti-Fe and V-Fe. After that, a mathematics correction method of exponential fitting was used to fit the R(K)-W(K) curve and get a function equation of X-ray fluorescence count rate and content. Three groups of Ti-V duality samples were used to test the fitting method and the relative errors of Ti and V were less than 0.2% as compared to the actual results.

  2. Optical absorption and fluorescence studies of praseodymium ion in chloroborophosphate glasses

    International Nuclear Information System (INIS)

    Sharma, Y.K.; Tandon, S.P.

    1998-01-01

    Full text: The interest in optical absorption and fluorescence studies of rare earth ions in glassy materials is increasing continuously in connection with laser research and related application. The absorption and fluorescence spectra of praseodymium ion in chloroborophosphate glasses have been recorded at room temperature. The chloroborophosphate glass specimens having composition in mob.% Na 2 0 (26.08), B 2 0 3 (14.57), P 2 0 5 (44.85), ZnCl 2 (14.50), Pr 6 0 11 (R) [R= 0.0,0.1 and 0.2 moi.%] have been prepared by melt quenching technique. The spectra consists of seven absorption bands and three fluorescence bands. The observed optical spectra are discussed in terms of energy state and the intensity of the transitions. The various energy interaction parameters like Slater-Condon, Lande', Racah and bonding parameters have been computed. Judd-Ofeit intensity parameters and laser parameters have also been computed. These results shows that praseodymium doped chloroborophosphate glass specimen can be considered as good hosts for laser applications

  3. Study of elementary absorption in the marine sediments of the North Atlantic ocean deeps

    International Nuclear Information System (INIS)

    Rancon, D.; Guegueniat, P.

    1984-01-01

    We have studied the retention of actinide elements (Np, Pu, Am) and of Cs in the sediments of the ocean deeps around Cap-Vert. Plutonium: retention increases with temperatures of 4 to 30 0 C, then stays constant from 30 to 80 0 C. Desorption is slow. Americium: absorption is very strong at any temperature. Measurements of a wide variety of sediments show that retention is not affected by facies (including carbonated sediments). Neptunium: retention is more or less constant between 4 and 15 0 C, and distinctly higher at 30-50 0 C. It is reversible. Caesium: absorption decreases slightly from 4 to 30 0 C, but increases rapidly at 50 to 80 0 C. At the lowest temperatures it is reversible, but it appears to be irreversible at 50 0 . Cs absorption is subject to ponderal concentration. With equal amounts of activity, retention of Cs-135 is weaker than that of Cs-137: likewise the addition of the stable isotope causes in the amounts of Kd in Cs-137. Finally, this paper presents preliminary results showing the natural metallic element content of the sediments

  4. Studies on absorption of EC waves in assisted startup experiment on FTU

    Science.gov (United States)

    Granucci, G.; Ricci, D.; Farina, D.; Figini, L.; Iraji, D.; Tudisco, O.; Ramponi, G.; Bin, W.

    2012-09-01

    Assistance of EC wave for plasma breakdown and current ramp up is the proposed scenario for the ITER case, characterized by low toroidal electric field. The experimental results on many tokamaks clearly indicate the capabilities of the proposed scheme to have a robust breakdown in ITER. The key aspect of this technique is the EC power required, strongly related to the absorption of the wave in the initial stage of plasma formation. This aspect is generally neglected due to the diagnostics difficulties in the plasma formation phase. As a consequence a multi-pass absorption scheme is usually considered reasonable, leading to a strong absorption after many reflections on the walls. The present study exploits the high temporal and spatial resolution of the fast scanning interferometer of FTU together with the measure of residual power obtained by a sniffer probe. The absorbed EC power is calculated considering also the polarization rotation and the subsequent mode conversion after incidence on the internal wall and compared with that derived from experimental data. The resulting EC power distribution can explain differences observed between perpendicular and oblique injection results, indicating future investigations to define ITER power requirements.

  5. Study of the texture of porous solids using a technique of γ ray absorption

    International Nuclear Information System (INIS)

    Ortega, M.

    1967-01-01

    A technique, which enables us to measure locally total porosity, open porosity and pore size distribution is developed. The total porosity is calculated from the bulk density. A gamma absorption gauge is set up fitted with a Cs137 source. This enables the determination of the density by layers of carbonaceous samples in a practically automatic way. By taking adequate precautions it is possible to obtain the density with a maximum error Δρ ≤ 0,005 g/cm 3 . The open porosity is evaluated by the absorption method after impregnation with bromoform. A new mercury porosimeter is developed using the absorption probe for the measurement of mercury infiltrated into the porous sample. Due to the localized character of exploration by this technique, the variations of porous texture in a heterogeneous sample can be studied. Used as a classical porosimeter, in the case of homogeneous samples, this apparatus is capable of exploring the equivalent diameters of pores between 500 μ and 0.14 μ with a maximum error ΔP ≤ 0.002. The possibility of exploration of heterogeneous samples, with the facility of determination of porosities due to macro-pores combined with the non-limiting character of the method in the field of high pressures differentiates this apparatus from all the porosimeters of former conception. Examples of utilization of this technique in the case of graphite-gas reactions are presented. (author) [fr

  6. Studies on absorption of EC waves in assisted startup experiment on FTU

    Directory of Open Access Journals (Sweden)

    Ramponi G.

    2012-09-01

    Full Text Available Assistance of EC wave for plasma breakdown and current ramp up is the proposed scenario for the ITER case, characterized by low toroidal electric field. The experimental results on many tokamaks clearly indicate the capabilities of the proposed scheme to have a robust breakdown in ITER. The key aspect of this technique is the EC power required, strongly related to the absorption of the wave in the initial stage of plasma formation. This aspect is generally neglected due to the diagnostics difficulties in the plasma formation phase. As a consequence a multi-pass absorption scheme is usually considered reasonable, leading to a strong absorption after many reflections on the walls. The present study exploits the high temporal and spatial resolution of the fast scanning interferometer of FTU together with the measure of residual power obtained by a sniffer probe. The absorbed EC power is calculated considering also the polarization rotation and the subsequent mode conversion after incidence on the internal wall and compared with that derived from experimental data. The resulting EC power distribution can explain differences observed between perpendicular and oblique injection results, indicating future investigations to define ITER power requirements.

  7. Optical absorption and gamma-radiation-shielding parameter studies of Tm3+-doped multicomponent borosilicate glasses

    Science.gov (United States)

    Lakshminarayana, G.; Sayyed, M. I.; Baki, S. O.; Lira, A.; Dong, M. G.; Kaky, Kawa M.; Kityk, I. V.; Mahdi, M. A.

    2018-05-01

    Different concentrations (0.1‒2.0 mol%) of Tm3+-doped multicomponent borosilicate glasses with 10 mol% Li2O (alkali) or MgO (alkaline) have been synthesized and their optical absorption and radiation shielding features were studied. For both Li2O and MgO series 0.5 mol% Tm3+-doped glass samples, the evaluated Ωλ ( λ = 2, 4, and 6) Judd-Ofelt (JO) intensity parameters from experimental oscillator strengths were used in estimating the radiative transition probabilities ( A R), branching ratios ( β R), and radiative lifetimes ( τ R) for several emission transitions. Using the XCOM software, the mass attenuation coefficients ( µ/ ρ) for all the fabricated glasses were evaluated within the 0.015‒10 MeV energy range. Also, the ( µ/ ρ) values were calculated at 0.356, 0.662, 1.173, and 1.33 MeV photon energies by MCNP5 simulation code and the results were compared with those obtained by XCOM. The ( µ/ ρ) values for Li2O, as well as MgO series glasses, increase with the addition of Tm2O3 and these values for MgO series glasses are slightly higher with respect to Li2O series glasses. From the ( µ/ ρ) values, effective atomic number ( Z eff), half-value layer (HVL), and mean free path (MFP) were calculated and the HVL and MFP results revealed that high-energy photons have more penetration into a glass sample compared to low-energy photons. Further, geometric progression (GP) fitting method was utilized to calculate the exposure buildup factor (EBF) within the 0.015‒15 MeV energy range. The 2.0 mol% Tm2O3-doped glasses show a better ability to attenuate gamma-rays in comparison to other glass samples, so the addition of Tm2O3 content leads to improvement of the shielding efficiency of the prepared glasses.

  8. Dynamics of Charged Excitons and Biexcitons in CsPbBr3 Perovskite Nanocrystals Revealed by Femtosecond Transient-Absorption and Single-Dot Luminescence Spectroscopy.

    Science.gov (United States)

    Yarita, Naoki; Tahara, Hirokazu; Ihara, Toshiyuki; Kawawaki, Tokuhisa; Sato, Ryota; Saruyama, Masaki; Teranishi, Toshiharu; Kanemitsu, Yoshihiko

    2017-04-06

    Metal-halide perovskite nanocrystals (NCs) are promising photonic materials for use in solar cells, light-emitting diodes, and lasers. The optoelectronic properties of these devices are determined by the excitons and exciton complexes confined in their NCs. In this study, we determined the relaxation dynamics of charged excitons and biexcitons in CsPbBr 3 NCs using femtosecond transient-absorption (TA), time-resolved photoluminescence (PL), and single-dot second-order photon correlation spectroscopy. Decay times of ∼40 and ∼200 ps were obtained from the TA and PL decay curves for biexcitons and charged excitons, respectively, in NCs with an average edge length of 7.7 nm. The existence of charged excitons even under weak photoexcitation was confirmed by the second-order photon correlation measurements. We found that charged excitons play a dominant role in luminescence processes of CsPbBr 3 NCs. Combining different spectroscopic techniques enabled us to clarify the dynamical behaviors of excitons, charged excitons, and biexcitons.

  9. Comprehensive study of the effects of age, iron deficiency, diabetes mellitus, and cadmium burden on dietary cadmium absorption in cadmium-exposed female Japanese farmers

    International Nuclear Information System (INIS)

    Horiguchi, Hyogo; Oguma, Etsuko; Sasaki, Satoshi; Miyamoto, Kayoko; Ikeda, Yoko; Machida, Munehito; Kayama, Fujio

    2004-01-01

    The absorption rate of dietary cadmium (Cd) was investigated among 38 female farmers who had been exposed to Cd at levels close to the current provisional tolerable weekly intake (PTWI); these levels were much higher than those examined in previous studies. The study group composed of 7 diabetics and their 13 age-matched controls and 6 anemic subjects and their 12 controls. With their informed consent, the study participants were confined in an inn for 7 nights and 8 days to collect all feces and urine and duplicates of all food consumed. The dietary Cd absorption rate was calculated for each subject from her total Cd intake and fecal excretion. The means and 95% confidence intervals (CI) of the diabetic group and the anemic group did not differ significantly from those of their respective controls. By individual analysis using all 38 subjects, however, significant Pearson's correlation coefficients were observed between Cd absorption rate and age, serum ferritin, serum iron, and blood and urine Cd levels. Among these, multiple regression analysis revealed that only age was a significant factor contributing to Cd absorption rate. The actual Cd absorption rate in the youngest age group (20-39 years) was 44.0%, which was highly accelerated compared with the rate in the total subject group of 6.5%, while zero to negative balance was observed in the older subjects. These results demonstrate that age, rather than iron deficiency, diabetes mellitus (DM), or Cd burden, is the only independent factor affecting the Cd absorption rate, suggesting that young women are always at high risk

  10. Study of percutaneous absorption of diclofenac diethylamine in the presence of cetrimide through hairless rabbit skin

    International Nuclear Information System (INIS)

    Hussain, S. N.; Rabbain, M.; Amir, M. F.

    2006-01-01

    In the present study, the effect of Cetrimide as an enhancer on transdermal absorption of 1% diclofenac diethylamine (Non-steroidal Anti-inflammatory Drug) through hairless rabbit skin was evaluated in vitro study at various concentrations to improve the skin permeability. From the data, Cetrimide shows the small lag time which gives a picture about its enhancing effect. The permeability co-efficient and flux rate calculated for diclofenac diethylamine in the presence of Cetrimide shows that the penetration of drug through hairless rabbit skin has been significantly increased. (author)

  11. In-situ x-ray absorption study of copper films in ground water solutions

    International Nuclear Information System (INIS)

    Kvashnina, K.O.; Butorin, S.M.; Modin, A.; Soroka, I.; Marcellini, M.; Nordgren, J.; Guo, J.-H.; Werme, L.

    2007-01-01

    This study illustrates how the damage from copper corrosion can be reduced by modifying the chemistry of the copper surface environment. The surface modification of oxidized copper films induced by chemical reaction with Cl - and HCO 3 - in aqueous solutions was monitored by in situ X-ray absorption spectroscopy. The results show that corrosion of copper can be significantly reduced by adding even a small amount of sodium bicarbonate. The studied copper films corroded quickly in chloride solutions, whereas the same solution containing 1.1 mM HCO 3 - prevented or slowed down the corrosion processes

  12. Mechanistic studies of ocular peptide absorption and its enhancement by various penetration enhancers

    International Nuclear Information System (INIS)

    Rojanasakul, Y.

    1989-01-01

    Two major aspects of corneal peptide absorption, namely the transport mechanisms and the promoting effect of some penetration enhancers, were investigated. Studies on transport mechanisms involve (a) identification of transport pathways of peptides across the cornea, (b) determination of rate-limiting barrier(s) for peptide absorption, and (c) permselective properties of the cornea. To study the transport pathways of peptides, four model peptides differing in molecular size and charge were either fluorescently or radioactively labeled and their movement across the cornea was detected by laser scanning confocal microscopy and autoradiography. Results from these studies indicate that peptides can penetrate the cornea via different pathways, depending on the physicochemical properties and membrane specificity of the peptides. In all cases, the outermost layer of the corneal epithelium presents the rate-limiting barrier for peptide absorption. The results also indicate a charge discrimination effect to transport of negatively charged peptides. In permselectivity studies, it has been shown that the cornea, due to the presence of ionizable charged groups, is amphoteric and exhibits dual selective characteristics to transport of charged molecules. At pH's above the isoelectric point, 3.2, the cornea carries a net negative charge and is selective to positively-charged molecules. Below the isoelectric pH, the reverse is valid. The promoting mechanisms of penetration enhancers were studied microscopically using confocal fluorescence microscopy with the aid of a specific fluorescent membrane probe (3,3'-dioctadecyloxacarbocyanine) and a non-permeating polar tracer. All enhancers, including chelators, non-ionic surfactants, bile salts, and cytoskeleton-active agents, significantly increase membrane permeability depending on concentration and exposure time

  13. X-ray absorption spectroscopy and EPR studies of oriented spinach thylakoid preparations

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, J.C. [Univ. of California, Berkeley, CA (United States). Dept. of Chemistry]|[Lawrence Berkeley Lab., CA (United States). Structural Biology Div.

    1995-08-01

    In this study, oriented Photosystem II (PS II) particles from spinach chloroplasts are studied with electron paramagnetic resonance (EPR) and x-ray absorption spectroscopy (XAS) to determine more details of the structure of the oxygen evolving complex (OEC). The nature of halide binding to Mn is also studied with Cl K-edge and Mn EXAFS (extended x-ray absorption fine structure) of Mn-Cl model compounds, and with Mn EXAFS of oriented PS II in which Br has replaced Cl. Attention is focused on the following: photosynthesis and the oxygen evolving complex; determination of mosaic spread in oriented photosystem II particles from signal II EPR measurement; oriented EXAFS--studies of PS II in the S{sub 2} state; structural changes in PS II as a result of treatment with ammonia: EPR and XAS studies; studies of halide binding to Mn: Cl K-edge and Mn EXAFS of Mn-Cl model compounds and Mn EXAFS of oriented Br-treated photosystem II.

  14. In Vitro Studies on the Absorption and Interactions of Zinc, Copper ...

    African Journals Online (AJOL)

    Background: The exact details of the processes of trace metals absorption and interactions in the gastro intestinal tract remain uncertain. Absorption for the most part, takes places in the small intestine. The exact site of maximum absorption, as defined either by kinetic rate or quantity has not been clearly defined. Similarly ...

  15. The absorption factor of crystalline silicon PV cells: a numerical and experimental study

    NARCIS (Netherlands)

    Santbergen, R.; Zolingen, van R.J.C.

    2008-01-01

    The absorption factor of a PV cell is defined as the fraction of incident solar irradiance that is absorbed by the cell. This absorption factor is one of the major parameters determining the cell temperature under operational conditions. Experimentally the absorption factor can be derived from

  16. Optical absorption studies on biodegradable PVA/PVP blend polymer electrolyte system

    Science.gov (United States)

    Basha, S. K. Shahenoor; Reddy, K. Veera Bhadra; Rao, M. C.

    2018-05-01

    Biodegradable blend polymer electrolytes of PVA/PVP with different wt% ratios of MgCl2.6H2O have been prepared using solution cast technique. Optical absorption studies were carried-out on to the prepared films at room temperature using JASCO V-670 Spectrophotometer in the wavelength region 200-600 nm. Due to the clusters between the vibrations of molecules a broad peak is obtained due to п-п* transition in the wavelength region 310-340 nm.

  17. Absorption of selected radionuclides. Analysis of a literature study. Resorption ausgewaehlter Radionuklide. Analyse einer Literaturstudie

    Energy Technology Data Exchange (ETDEWEB)

    Roedler, H D; Kraus, H M

    1979-12-01

    In October 1978, the Institut fuer Energie- und Umweltforschung Heidelberg e.V. published a contribution to part 26 of the model study of radio-ecology at Biblis under the title 'Estimation of the absorption of radionuclides from the gastrointestinal tract in the blood'. Using the example of this contribution, a critical analysis is made to show how a selection of the information contained in various scientific publications and other items of literature can give uncritical readers the impression that all statements made are scientifically well founded.

  18. A review of radioisotope techniques in the study of vitamin B12 absorption

    International Nuclear Information System (INIS)

    Boddy, K.

    1976-01-01

    The five in vivo tests in common use for the study of vitamin B 12 absorption, namely, 1) faecal excretion method, 2) urinary excretion method, 3) plasma radioactivity method, 4) hepatic uptake method, and 5) whole-body counting method, are described. The merits, disadvantages and limitations of each method are considered in a clinical context. Whole-body counting is regarded as the method of choice where appropriate facilities are available and when the delay of about 7 days in obtaining the result is acceptable. The plasma radioactivity method can provide concurrently a rapid assessment. (author)

  19. X-ray absorption in GaGdN: A study of local structure

    Science.gov (United States)

    Martínez-Criado, G.; Sancho-Juan, O.; Garro, N.; Sans, J. A.; Cantarero, A.; Susini, J.; Roever, M.; Mai, D.-D.; Bedoya-Pinto, A.; Malindretos, J.; Rizzi, A.

    2008-07-01

    In this study, we report on the incorporation of dilute Gd amounts into GaN films grown by molecular beam epitaxy. A combination of x-ray fluorescence with x-ray absorption spectroscopic techniques enabled us to examine not only the distribution of rare earth atoms in the GaN matrix but also the short-range structural order. Our results show Gd atoms in a trivalent state with tetrahedral coordination, thus substituting Ga in the wurtzite GaN structure.

  20. X-ray absorption in GaGdN: A study of local structure

    International Nuclear Information System (INIS)

    Martinez-Criado, G.; Sans, J. A.; Susini, J.; Sancho-Juan, O.; Cantarero, A.; Garro, N.; Roever, M.; Mai, D.-D.; Bedoya-Pinto, A.; Malindretos, J.; Rizzi, A.

    2008-01-01

    In this study, we report on the incorporation of dilute Gd amounts into GaN films grown by molecular beam epitaxy. A combination of x-ray fluorescence with x-ray absorption spectroscopic techniques enabled us to examine not only the distribution of rare earth atoms in the GaN matrix but also the short-range structural order. Our results show Gd atoms in a trivalent state with tetrahedral coordination, thus substituting Ga in the wurtzite GaN structure

  1. Extended X-ray absorption fine structure (EXAFS) studies of supported catalysts

    International Nuclear Information System (INIS)

    Joyner, R.W.

    1979-01-01

    Since the rebirth of interest in extended X-ray absorption fine structure there have been several studies of systems of catalytic interest. This note is a preliminary account of an investigation of supported platinum catalysts and NiO/Al 2 O 3 catalysts. Experiments were performed on pressed disc samples at the DESY synchrotron, Hamburg, using the EXAFS spectrometer. The synchrotron operated at 7 GeV energy with a circulating current of approximately 4 mA; spectrum accumulation time was typically 45 minutes. (author)

  2. Human in vivo and in vitro studies on gastrointestinal absorption of titanium dioxide nanoparticles.

    Science.gov (United States)

    Jones, Kate; Morton, Jackie; Smith, Ian; Jurkschat, Kerstin; Harding, Anne-Helen; Evans, Gareth

    2015-03-04

    The study was designed to conduct human in vivo and in vitro studies on the gastrointestinal absorption of nanoparticles, using titanium dioxide as a model compound, and to compare nanoparticle behaviour with that of larger particles. A supplier's characterisation data may not fully describe a particle formulation. Most particles tested agreed with their supplied characterisation when assessed by particle number but significant proportions of 'nanoparticle formulations' were particles >100nm when assessed by particle weight. Oral doses are measured by weight and it is therefore important that the weight characterisation is taken into consideration. The human volunteer studies demonstrated that very little titanium dioxide is absorbed gastrointestinally after an oral challenge. There was no demonstrable difference in absorption for any of the three particle sizes tested. All tested formulations were shown to agglomerate in simulated gastric fluid, particularly in the smaller particle formulations. Further agglomeration was observed when dispersing formulations in polymeric or elemental foods. Virtually no translocation of titanium dioxide particles across the cell layer was demonstrated. This study found no evidence that nanoparticulate titanium dioxide is more likely to be absorbed in the gut than micron-sized particles. Crown Copyright © 2015. Published by Elsevier Ireland Ltd. All rights reserved.

  3. NuSTAR reveals an intrinsically x-ray weak broad absorption line quasar in the ultraluminous infrared galaxy Markarian 231

    DEFF Research Database (Denmark)

    Teng, Stacy H.; Brandt, W. N.; Harrison, F. A.

    2014-01-01

    -ionization broad absorption line quasar that is intrinsically X-ray weak. The weak ionizing continuum may explain the lack of mid-infrared [O IV], [Ne V], and [Ne VI] fine-structure emission lines which are present in sources with otherwise similar AGN properties. We argue that the intrinsic X-ray weakness may...

  4. Transcriptional analysis of porcine intestinal mucosa infected with Salmonella Typhimurium revealed a massive inflammatory response and disruption of bile acid absorption in ileum

    DEFF Research Database (Denmark)

    Uribe, Juber Herrera; Collado-Romero, Melania; Zaldívar-López, Sara

    2016-01-01

    -regulated genes of the FXR pathway (e.g., NR1H4, FABP6, APOA1, SLC10A2), indicating disruption of the bile acid absorption in ileum. This result was confirmed by decreased high-density lipoprotein cholesterol in serum of infected pigs. Ileal inflammatory gene expression changes peaked at 2 dpi and tended...

  5. Mixed-Alkali Effect in Li2O-Na2O-K2O-B2O3 Glasses: Infrared and Optical Absorption Studies

    Science.gov (United States)

    Samee, M. A.; Edukondalu, A.; Ahmmad, Shaik Kareem; Taqiullah, Sair Md.; Rahman, Syed

    2013-08-01

    The mixed-alkali effect (MAE) has been investigated in the glass system (40 - x)Li2O- xNa2O-10K2O-50B2O3 (0 mol% ≤ x ≤ 40 mol%) through density, modulated differential scanning calorimetry (DSC), and optical absorption studies. From the absorption studies, the values of the optical band gap ( E opt) for direct transition and Urbach energy (Δ E) have been evaluated. The values of E opt and Δ E show nonlinear behavior with the compositional parameter. The density and glass-transition temperature of the present glasses also show nonlinear variation, supporting the existence of MAE. The infrared (IR) spectra of the glasses reveal the presence of three- and four-coordinated boron atoms. The specific vibrations of Li-O, Na-O, and K-O bonds were observed in the present IR study.

  6. Deuterium absorption in Mg{sub 70}Al{sub 30} thin films with bilayer catalysts: A comparative neutron reflectometry study

    Energy Technology Data Exchange (ETDEWEB)

    Poirier, Eric [National Research Council Canada/Canadian Neutron Beam Centre, Bldg. 459, Chalk River Laboratories, Chalk River, ON, K0J 1J0 (Canada); Harrower, Chris T.; Kalisvaart, Peter [Chemical and Materials Engineering, University of Alberta and National Research Council Canada/National Institute for Nanotechnology, Edmonton, AB, T6G 2M9 (Canada); Bird, Adam [National Research Council Canada/Canadian Neutron Beam Centre, Bldg. 459, Chalk River Laboratories, Chalk River, ON, K0J 1J0 (Canada); Teichert, Anke [Helmholtz Zentrum Berlin, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Instituut voor Kern-en Stralingsfysica and INPAC, K.U. Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium); Laboratorium voor Vaste-Stoffysica en Magnetisme and INPAC, K.U. Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium); Wallacher, Dirk; Grimm, Nico; Steitz, Roland [Helmholtz Zentrum Berlin, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Mitlin, David [Chemical and Materials Engineering, University of Alberta and National Research Council Canada/National Institute for Nanotechnology, Edmonton, AB, T6G 2M9 (Canada); Fritzsche, Helmut, E-mail: Helmut.Fritzsche@nrc-cnrc.gc.ca [National Research Council Canada/Canadian Neutron Beam Centre, Bldg. 459, Chalk River Laboratories, Chalk River, ON, K0J 1J0 (Canada)

    2011-05-05

    Highlights: > Mg{sub 70}Al{sub 30} thin films studied for hydrogen absorption using in situ neutron reflectometry. > Films with Ta/Pd, Ti/Pd and Ni/Pd bilayer catalysts systematically compared. > Measurements reveals deuterium spillover from the catalysts to the MgAl phase. > The use of Ti-Pd bilayer offers best results in terms of amount absorbed and kinetics. > Key results cross-checked with X-ray reflectometry. - Abstract: We present a neutron reflectometry study of deuterium absorption in thin films of Al-containing Mg alloys capped with a Ta/Pd, Ni/Pd and Ti/Pd-catalyst bilayer. The measurements were performed at room temperature over the 0-1 bar pressure range under quasi-equilibrium conditions. The modeling of the measurements provided a nanoscale representation of the deuterium profile in the layers at different stages of the absorption process. The absorption mechanism observed was found to involve spillover of atomic deuterium from the catalyst layer to the Mg alloy phase, followed by the deuteration of the Mg alloy. Complete deuteration of the Mg alloy occurs in a pressure range between 100 and 500 mbar, dependent on the type of bilayer catalyst. The use of a Ti/Pd bilayer catalyst yielded the best results in terms of both storage density and kinetic properties.

  7. Study Of Soot Growth And Nucleation By A Time-Resolved Synchrotron Radiation Based X-Ray Absorption Method

    National Research Council Canada - National Science Library

    Mitchell, Judith I

    2001-01-01

    This report results from a contract tasking University of Rennes I as follows: The contractor will perform a study of soot growth and nucleation by a time-resolved synchrotron radiation based x-ray absorption method...

  8. Experimental study of absorption of iron in foods using whole-body counter

    International Nuclear Information System (INIS)

    Nakamura, Tadamitsu

    1978-01-01

    Male rats of Wistar strain which showed normal hematological picture were given 59 Fe-labeled foods orally, and the iron absorption rate was determined by an animal whole body counter. When 59 Fe was given in a mixture with each of gruel, spinach, cow's milk, the yolk, and the yolk with orange juice, the iron absorption rates in each food were 9.4%, 8.9%, 6.6%, 10.8% and 7.2% respectively. None of these foods seemed to inhibit the 59 Fe absorption. When 59 Fe was given in a mixture with chicken, the iron absorption rate was 35.8%. This result suggested that the chicken promoted the 59 Fe absorption. When the yolk labeled in vivo with 59 Fe was given, the iron absorption rate was 4.9%. If the yolk labeled in vitro was used, the absorption rate was 10.8%. When the yolk labeled in vivo with 59 Fe was given with orange juice, the iron absorption rate was 13.3%. If the yolk labeled in vivo with 59 Fe was given, the absorption rate was 7.2%. Orange juice had no effect on the iron absorption when the yolk labeled in vitro was used. After chicken eggs labeled in vivo with 59 Fe was given to children, the iron absorption was determined by a whole body counter; the rate averaged 5.4 in the children without anemia and 24.7 in those with anemia. (Ueda, J.)

  9. Study of the effect of Chinese medicine on calcium absorption with isotopic tracer technique

    International Nuclear Information System (INIS)

    Hu, S.M.; Mao, X.Y.; Feng, W.Y.; OY, H.; Wang, M.; Xu, D.D.; Zhang, F.; Chai, Z.F.

    2005-01-01

    The present work was undertaken to study the effect of Chinese medicine on calcium absorption. Female Wistar rats, 3 months old, weighing 250-275 g, were randomly divided into ten groups of 5 rats each. The rats were individually housed in stainless steel metabolic cages in an environmentally controlled room (temperature, 20 degree C; relative humidity, 30%-60%; reversed light : dark cycle, 12:12 hr). Isotopic tracer technique was conducted to study the absorption of calcium acetate and calcium acetate + Chinese medicine in rats. The two calcium supplements were irradiated in a nuclear reactor for 4.95 d at neutron flux of φ=6.1 x 10 13 n/cm 2 ·s. Then they were prepared from concentrated 47 Ca solution (10 mg/ml) with cyclodextrin. The animals received oral doses of 25 mg calcium as calcium acetate or calcium acetate + Chinese medicine via an intragastric gavage. The animals were fasted overnight preceding and food was resumed 3 hrs after the gavage. Blood, heart, lung, liver, spleen, stomach, kidney, small intestine, large intestine and femur samples of the rats were taken upon sacrifice at 0.5, 1, 2, 4, 12, 24, 48, 72, 120, 168 hrs after dosing and assayed for 47 Ca. Urine and feces samples were collected separately after dosing and assayed for 47 Ca. The radioactivity of the samples was counted with a high pure Ge detector and a PC-based Ortec MCA. Its energy resolution was l.85 keV at 1332.5 keV and the relative detection efficiency was 30 %. The dead time was controlled within 10 % to reduce the count loss. Weighed 47 CaCO 3 was used as reference materials. A big distance between the samples and detector was kept to overcome the geometric effect caused by different shape and size of the samples. The gamma energy spectra were analyzed with a multipurpose gamma ray spectrum analysis software package. The parameters were evaluated by means of general linear model, using analysis of covariance with SAS 6.12 for Windows. The results showed that peroral 47 Ca was

  10. [Estimation of DOC concentrations using CDOM absorption coefficients: a case study in Taihu Lake].

    Science.gov (United States)

    Jiang, Guang-Jia; Ma, Rong-Hua; Duan, Hong-Tao

    2012-07-01

    Dissolved organic carbon (DOC) is the largest organic carbon stock in water ecosystems, which plays an important role in the carbon cycle in water. Chromophoric dissolved organic matter (CDOM), an important water color variation, is the colored fraction of DOC and its absorption controls the instruction of light under water. The available linkage between DOC concentration and CDOM absorptions enables the determination of DOC accumulations using remote sensing reflectance or radiance in lake waters. The present study explored the multi-liner relationship between CDOM absorptions [a(g) (250) and a(g) (365)] and DOC concentrations in Taihu Lake, based on the available data in 4 cruises (201005, 201101, 201103, 201105) (totally 183 sampling sites). Meanwhile, the results were validated with the data of the experiment carried out from August 29 to September 2, 2011 in Taihu Lake (n = 27). Furthermore, a universal pattern of modeling from remote sensing was built for lake waters. The results demonstrated that this method provided more satisfying estimation of DOC concentrations in Taihu Lake. Except the data obtained in January 2011, the fitted results of which were not conductive to the winter dataset (201101) in Taihu Lake, due to the diverse sources and sinks of DOC and CDOM, the multi-liner relationship was robust for the data collected in the other three cruises (R2 = 0.64, RMSE = 14.31%, n = 164), which was validated using the 201108 sampling dataset (R2 = 0.67, RMSE = 10.58%, n = 27). In addition, the form of the statistic model is universal, to some extent, for other water areas, however, there is difference in the modeling coefficients. Further research should be focused on the parameterization using local data from different lakes, which provides effective methodology for the estimation of DOC concentrations in lakes and other water regions.

  11. Experimental Study on Compression/Absorption High-Temperature Hybrid Heat Pump with Natural Refrigerant Mixture

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ji Young; Park, Seong Ryong; Baik, Young Jin; Chang, Ki Chang; Ra, Ho Sang; Kim, Min Sung [Korea Institute of Energy Research, Daejeon (Korea, Republic of); Kim, Yong Chan [Korea University, Seoul (Korea, Republic of)

    2011-12-15

    This research concerns the development of a compression/absorption high-temperature hybrid heat pump that uses a natural refrigerant mixture. Heat pumps based on the compression/absorption cycle offer various advantages over conventional heat pumps based on the vapor compression cycle, such as large temperature glide, temperature lift, flexible operating range, and capacity control. In this study, a lab-scale prototype hybrid heat pump was constructed with a two-stage compressor, absorber, desorber, desuperheater, solution heat exchanger, solution pump, liquid/vapor separator, and rectifier as the main components. The hybrid heat pump system operated at 10-kW-class heating capacity producing hot water whose temperature was more than 90 .deg. C when the heat source and sink temperatures were 50 .deg. C. Experiments with various NH{sub 3}/H{sub 2}O mass fractions and compressor/pump circulation ratios were performed on the system. From the study, the system performance was optimized at a specific NH{sub 3} concentration.

  12. VUV Fourier-transform absorption study of the Lyman and Werner bands in D2

    Science.gov (United States)

    de Lange, Arno; Dickenson, Gareth D.; Salumbides, Edcel J.; Ubachs, Wim; de Oliveira, Nelson; Joyeux, Denis; Nahon, Laurent

    2012-06-01

    An extensive survey of the D2 absorption spectrum has been performed with the high-resolution VUV Fourier-transform spectrometer employing synchrotron radiation. The frequency range of 90 000-119 000 cm-1 covers the full depth of the potential wells of the B sideset{^1}{+u}{Σ}, B^' } sideset{^1}{+u}{Σ}, and C 1Πu electronic states up to the D(1s) + D(2ℓ) dissociation limit. Improved level energies of rovibrational levels have been determined up to respectively v = 51, v = 13, and v = 20. Highest resolution is achieved by probing absorption in a molecular gas jet with slit geometry, as well as in a liquid helium cooled static gas cell, resulting in line widths of ≈0.35 cm-1. Extended calibration methods are employed to extract line positions of D2 lines at absolute accuracies of 0.03 cm-1. The D 1Πu and B^' ' } sideset{^1}{+u}{Σ} electronic states correlate with the D(1s) + D(3ℓ) dissociation limit, but support a few vibrational levels below the second dissociation limit, respectively, v = 0-3 and v = 0-1, and are also included in the presented study. The complete set of resulting level energies is the most comprehensive and accurate data set for D2. The observations are compared with previous studies, both experimental and theoretical.

  13. Experimental study of radiative energy transport in dense plasmas by emission and absorption spectroscopy

    International Nuclear Information System (INIS)

    Dozieres, Maylis

    2016-01-01

    This PhD work is an experimental study, based on emission and absorption spectroscopy of hot and dense nanosecond laser-produced plasmas. Atomic physics in such plasmas is a complex subject and of great interest especially in the fields of astrophysics or inertial confinement fusion. On the atomic physics point of view, this means determining parameters such as the average ionization or opacity in plasmas at given electronic temperature and density. Atomic physics codes then need of experimental data to improve themselves and be validated so that they can be predictive for a wide range of plasmas. With this work we focus on plasmas whose electronic temperature varies from 10 eV to more than a hundred and whose density range goes from 10 -5 ato10 -2 g/cm 3 . In this thesis, there are two types of spectroscopic data presented which are both useful and necessary to the development of atomic physics codes because they are both characteristic of the state of the studied plasma: 1) some absorption spectra from Cu, Ni and Al plasmas close to local thermodynamic equilibrium; 2) some emission spectra from non local thermodynamic equilibrium plasmas of C, Al and Cu. This work highlights the different experimental techniques and various comparisons with atomic physics codes and hydrodynamics codes. (author) [fr

  14. An experimental study on moisture absorption for jute-epoxy composite with coatings exposed to different pH media

    Directory of Open Access Journals (Sweden)

    Radhika Londhe

    2016-09-01

    The purpose of this work is to study the moisture absorption and mechanical properties of jute-epoxy composites. Jute fibres are treated with NaOH before manufacturing of composite laminate in order to improve adhesion with epoxy material. Further jute-epoxy composite specimens were coated with epoxy resin and acrylic paint. Composite specimens with and without coatings are subjected to absorption in solutions of different pH media, for 28 days (666 h. The effect of coatings on reduction in moisture absorption for jute-epoxy composite is presented in this current work.

  15. Results of Self-Absorption Study on the Versapor 3000 Filters for Radioactive Particulate Air Sampling

    International Nuclear Information System (INIS)

    Barnett, J.M.; Cullinan, Valerie I.; Barnett, Debra S.; Trang-Le, Truc LT; Bliss, Mary; Greenwood, Lawrence R.; Ballinger, Marcel Y.

    2009-01-01

    self-absorption effects. The microscopy analysis compares different filter loadings and shows that smaller particle sizes (under 10 micron) can readily be seen on the more lightly loaded filters. At higher loadings, however, the particle size is harder to differentiate. This study provides data on actual stack emission samples showing a range of mass loading conditions and visual evidence of particle size and distribution and also presents the difficulties in quantifying self-absorption effects using actual samples

  16. Molecular dynamics simulation and TDDFT study of the structures and UV-vis absorption spectra of MCT-β-CD and its inclusion complexes.

    Science.gov (United States)

    Lu, Huijuan; Wang, Yujiao; Xie, Xiaomei; Chen, Feifei; Li, Wei

    2015-01-01

    In this research, the inclusion ratios and inclusion constants of MCT-β-CD/PERM and MCT-β-CD/CYPERM inclusion complexes were measured by UV-vis and fluorescence spectroscopy. The inclusion ratios are both 1:1, and the inclusion constants are 60 and 342.5 for MCT-β-CD/PERM and MCT-β-CD/CYPERM, respectively. The stabilities of inclusion complexes were investigated by MD simulation. MD shows that VDW energy plays a vital role in the stability of inclusion complex, and the destruction of inclusion complex is due to the increasing temperature. The UV-vis absorption spectra of MCT-β-CD and its inclusion complexes were studied by time-dependent density functional theory (TDDFT) method employing BLYP-D3, B3LYP-D3 and M06-2X-D3 functionals. BLYP-D3 well reproduces the UV-vis absorption spectrum and reveals that the absorption bands of MCT-β-CD mainly arise from n→π(∗) and n→σ(∗) transition, and those of inclusion complexes mainly arise from intramolecular charge transfer (ICT). ICT results in the shift of main absorption bands of MCT-β-CD. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. X-ray Absorption Study of Graphene Oxide and Transition Metal Oxide Nanocomposites.

    Science.gov (United States)

    Gandhiraman, Ram P; Nordlund, Dennis; Javier, Cristina; Koehne, Jessica E; Chen, Bin; Meyyappan, M

    2014-08-14

    The surface properties of the electrode materials play a crucial role in determining the performance and efficiency of energy storage devices. Graphene oxide and nanostructures of 3d transition metal oxides were synthesized for construction of electrodes in supercapacitors, and the electronic structure and oxidation states were probed using near-edge X-ray absorption fine structure. Understanding the chemistry of graphene oxide would provide valuable insight into its reactivity and properties as the graphene oxide transformation to reduced-graphene oxide is a key step in the synthesis of the electrode materials. Polarized behavior of the synchrotron X-rays and the angular dependency of the near-edge X-ray absorption fine structures (NEXAFS) have been utilized to study the orientation of the σ and π bonds of the graphene oxide and graphene oxide-metal oxide nanocomposites. The core-level transitions of individual metal oxides and that of the graphene oxide nanocomposite showed that the interaction of graphene oxide with the metal oxide nanostructures has not altered the electronic structure of either of them. As the restoration of the π network is important for good electrical conductivity, the C K edge NEXAFS spectra of reduced graphene oxide nanocomposites confirms the same through increased intensity of the sp 2 -derived unoccupied states π* band. A pronounced angular dependency of the reduced sample and the formation of excitonic peaks confirmed the formation of extended conjugated network.

  18. X-ray absorption studies of graphite intercalates and metal-ammonia solutions

    International Nuclear Information System (INIS)

    Robertson, A.S.

    1979-09-01

    X-ray absorption spectroscopy (XAS) was used to study the arsenic fluorocomplexes, including the AsF 5 and AsF 6 - intercalates of graphite, and rubidium metal-ammonia solutions. The As-F distances obtained for AsF 3 and AsF 5 gas are both in excellent agreement with electron diffraction data (within 0.004 A). A superior measurement which is significantly shorter than the accepted value of the bond distance in an undistorted AsF 6 - octahedra is reported. Both the XAES and EXAFS data presented support the hypothesis that the AsF 5 oxidizes graphite upon intercalation to produce AsF 6 - and AsF 3 intercalant species. Changes in the Rb K-edge features which are consistent with the known properties of Rb-NH 3 are correlated with conductivity and delocalization of the solvated electrons. In the XAES region, intensity and position changes of absorption transitions are explained. In the EXAFS region, the Rb-N bond distance and the relative number of nitrogen atoms in the first shell are measured. XAS has been shown to provide unique information about the nature of the metal-ammonia phase separation, phase transition, and density fluctuations

  19. X-ray absorption study of silicon carbide thin film deposited by pulsed laser deposition

    International Nuclear Information System (INIS)

    Monaco, G.; Suman, M.; Garoli, D.; Pelizzo, M.G.; Nicolosi, P.

    2011-01-01

    Silicon carbide (SiC) is an important material for several applications ranging from electronics to Extreme UltraViolet (EUV) space optics. Crystalline cubic SiC (3C-SiC) has a wide band gap (near 2.4 eV) and it is a promising material to be used in high frequency and high energetic electronic devices. We have deposited, by means of pulsed laser deposition (PLD), different SiC films on sapphire and silicon substrates both at mild (650 o C) and at room temperature. The resulted films have different structures such as: highly oriented polycrystalline, polycrystalline and amorphous which have been studied by means of X-ray absorption spectroscopy (XAS) near the Si L 2,3 edge and the C K edge using PES (photoemission spectroscopy) for the analysis of the valence bands structure and film composition. The samples obtained by PLD have shown different spectra among the grown films, some of them showing typical 3C-SiC absorption structure, but also the presence of some Si-Si and graphitic bonds.

  20. The absorption and uptake of recombinant human follicle-stimulating hormone through vaginal subcutaneous injections - a pharmacokinetic study

    Science.gov (United States)

    Hsu, Chao-Chin; Kuo, Hsin-Chih; Hsu, Chao-Tien; Gu, Qing

    2009-01-01

    Background Follicle stimulating hormone (FSH) has been routinely used for ovulation induction. Because of rapid clearance of the hormone, FSH is commonly administered by daily intramuscular or subcutaneous injections in in-vitro fertilization (IVF). To reduce the number of visits to the clinic, an intermittent vaginal injection of rhFSH every 3 days employing the concepts of mesotherapy and uterine first-pass effect was invented and has successfully been applied in women receiving IVF treatment. This study was designed to monitor the pharmacokinetic pattern of rhFSH administered vaginally. Methods Twelve healthy women with regular ovulatory cycles were recruited. All volunteers received gonadotrophin-releasing hormone agonist to suppress pituitary function and were assigned to receive single dose recombinant human FSH (rhFSH, Puregon 300) either using conventional abdominal subcutaneous injection or vaginal subcutaneous injection in a randomized cross-over study. Serum samples were collected at pre- scheduled time intervals after injections of rhFSH to determine immunoreactive FSH levels. Pharmacokinetic parameters characterizing rate [maximal plasma concentrations (Cmax) and time of maximal plasma concentrations (tmax)] and extent [area under the plasma concentration-time curve (AUC) and clearance] of absorption of rhFSH were compared. Results Vaginal injection of rhFSH was well tolerated and no drug-related adverse reaction was noted. Our analysis revealed that tmax was significantly earlier (mean 6.67 versus 13.33 hours) and Cmax was significantly higher (mean 17.77 versus 13.96 IU/L) in vaginal versus abdominal injections. The AUC0-∞ was 1640 versus 1134 IU·hour/L in vaginal and abdominal injections, respectively. Smaller plasma elimination rate constant (0.011 versus 0.016 hour-1), longer mean residence time (106.58 versus 70.47 hours), and slower total body clearance (292.2 versus 400.1 mL/hour) were also found in vaginal injection. Conclusion The vaginal

  1. The absorption and uptake of recombinant human follicle-stimulating hormone through vaginal subcutaneous injections - a pharmacokinetic study

    Directory of Open Access Journals (Sweden)

    Kuo Hsin-Chih

    2009-10-01

    Full Text Available Abstract Background Follicle stimulating hormone (FSH has been routinely used for ovulation induction. Because of rapid clearance of the hormone, FSH is commonly administered by daily intramuscular or subcutaneous injections in in-vitro fertilization (IVF. To reduce the number of visits to the clinic, an intermittent vaginal injection of rhFSH every 3 days employing the concepts of mesotherapy and uterine first-pass effect was invented and has successfully been applied in women receiving IVF treatment. This study was designed to monitor the pharmacokinetic pattern of rhFSH administered vaginally. Methods Twelve healthy women with regular ovulatory cycles were recruited. All volunteers received gonadotrophin-releasing hormone agonist to suppress pituitary function and were assigned to receive single dose recombinant human FSH (rhFSH, Puregon 300 either using conventional abdominal subcutaneous injection or vaginal subcutaneous injection in a randomized cross-over study. Serum samples were collected at pre- scheduled time intervals after injections of rhFSH to determine immunoreactive FSH levels. Pharmacokinetic parameters characterizing rate [maximal plasma concentrations (Cmax and time of maximal plasma concentrations (tmax] and extent [area under the plasma concentration-time curve (AUC and clearance] of absorption of rhFSH were compared. Results Vaginal injection of rhFSH was well tolerated and no drug-related adverse reaction was noted. Our analysis revealed that tmax was significantly earlier (mean 6.67 versus 13.33 hours and Cmax was significantly higher (mean 17.77 versus 13.96 IU/L in vaginal versus abdominal injections. The AUC0-∞ was 1640 versus 1134 IU·hour/L in vaginal and abdominal injections, respectively. Smaller plasma elimination rate constant (0.011 versus 0.016 hour-1, longer mean residence time (106.58 versus 70.47 hours, and slower total body clearance (292.2 versus 400.1 mL/hour were also found in vaginal injection

  2. Revealing H I gas in emission and absorption on pc to kpc scales in a galaxy at z ˜ 0.017

    Science.gov (United States)

    Gupta, N.; Srianand, R.; Farnes, J. S.; Pidopryhora, Y.; Vivek, M.; Paragi, Z.; Noterdaeme, P.; Oosterloo, T.; Petitjean, P.

    2018-05-01

    We present a detailed study of the quasar-galaxy pair: J1243+4043-UGC 07904. The sight line of the background quasar ( zq = 1.5266) passes through a region of the galaxy (zg = 0.0169) at an impact parameter of 6.9 kpc with high metallicity (0.5 Z⊙) and negligible dust extinction. We detect H I 21-cm absorption from the foreground galaxy at arcsecond and milliarcsecond scales. For typical cold neutral medium (CNM) temperatures in the Milky Way, this 21-cm absorber can be classified as a damped Lyα absorber (DLA). We infer the harmonic mean spin temperature of the gas to be ˜400 K and for a simple two-phase medium we estimate the CNM fraction to be fCNM = 0.27. This is remarkably consistent with the CNM fraction observed in the Galaxy and less than that of high-redshift DLAs. The quasar exhibits a core-jet morphology on milliarcsecond scales, corresponding to an overall extent of ˜9 pc at zg. We show that the size of CNM absorbing clouds associated with the foreground galaxy is >5 pc and they may be part of cold gas structures that extend beyond ˜35 pc. Interestingly, the rotation measure of quasar J1243+4043 is higher than any other source in samples of quasars with high-z DLAs. However, we do not find any detectable differences in rotation measures and polarization fraction of sight lines with or without high-z (z ≥ 2) DLAs or low-z (z ≤ 0.3) 21-cm absorbers. Finally, the foreground galaxy UGC 07904 is also part of a galaxy group. We serendipitously detect H I 21-cm emission from four members of the group, and an ˜80 kpc long H I bridge connecting two of the other members. The latter, together with the properties of the group members, suggests that the group is a highly interactive environment.

  3. Molybdenum x-ray absorption studies of the mutant Kp nifV of nitrogenase MO-FE protein

    International Nuclear Information System (INIS)

    Eidsness, M.K.; Smith, B.E.; Flood, A.C.; Garner, C.D.; Cramer, S.P.

    1985-01-01

    The nifV mutant nitrogenase enzyme of Klebsiella pheumoniae exhibits altered substrate reducing activity. This nitrogenase mutant cannot fix N 2 in vivo but can reduce C 2 H 2 to C 2 H 4 . The nifV mutant enzyme differs further from the wild-type enzyme by CO inhibition of its H 2 evolution activity, up to 80%. The NifV - phenotype (NifV - Kp1) has been shown to be associated with the iron-molybdenum cofactor (FeMoco) in the Mo Fe protein which is generally accepted as the site for substrate reduction. An X-Ray absorption study of the Mo site in this mutant may reveal a difference in its FeMoco structure. The authors report here a comparison of Mo X-Ray absorption data from the nitrogenase enzymes of the wild-type and NifV - strains in three different forms: (1) as isolated, (2) dye-oxidized, and (3) fixing enzyme systems. Mo edge structure of NifV - Kp1 and wild-type enzymes are nearly identical. Small shifts to higher energies are observed in the oxidized and fixing states. Mo EXAFS of NifV - Kp1 and wild-type in the ''as isolated'' state appear indistinguishable. Curve fitting results best describe the molybdenum in FeMoco as bound by 4-5 S atoms at 2.36 A ,3 Fe atoms at 2.69 A, and 0-2 O(N) atoms at 2.19 A. The spectral similarity of these results concerning the nifV mutant FeMoco structure is discussed

  4. Study of interplanetary hydrogen from Lyman alpha emission and absorption determination

    International Nuclear Information System (INIS)

    Cazes, Serge.

    1979-09-01

    The purpose of the work submitted in this paper is to contribute to the study of interplanetary hydrogen from Lyman alpha emission and absorption measurements, carried out on board the D2A, OSO-8 and Copernicus satellites. This study, which was undertaken from the D2A satellite, moved us to study the interplanetary environment as from observations made from the following experiments placed on board the OSO-8 and Copernicus satellites. The experiment set up on board the OSO-8 satellite made it possible to obtain the profile of the solar alpha Lyman emission. An absorption profile was observed for the first time on these profiles and this made it possible to attribute them to interplanetary hydrogen and enabled us to make a direct and local determination of the solar ionization rate. - The spectrometer set up on board Copernicus made it possible to obtain the emission spectrum of the interplanetary environment at the same time as the geocorona. The overall velocity of the interplanetary environment was deduced from the Doppler shift between the two spectra. In the first part, the principle of the REA and POLAR experiments is recalled but only the REA experiment is described in detail, particularly the problems arising from the construction and calibration of the cell. In the second part, a study of the interplanetary environment made from the D2A determinations is presented in synthesized form. On the other hand, the study to which theses initial results led us is presented in detail. Finally, in the third part, the results obtained by means of the OSO-8 and Copernicus satellites are given [fr

  5. Orientation of One-Dimensional Silicon Polymer Films Studied by X-Ray Absorption Spectroscopy

    Directory of Open Access Journals (Sweden)

    Md. Abdul Mannan

    2012-01-01

    Full Text Available Molecular orientations for thin films of one-dimensional silicon polymers grown by vacuum evaporation have been assigned by near-edge X-ray absorption fine structure (NEXAFS using linearly polarized synchrotron radiation. The polymer investigated was polydimethylsilane (PDMS which is the simplest stable silicon polymer, and one of the candidate materials for one-dimensional molecular wire. For PDMS films deposited on highly oriented pyrolytic graphite (HOPG, four resonance peaks have been identified in the Si K-edge NEXAFS spectra. Among these peaks, the intensities of the two peaks lower-energy at 1842.0 eV and 1843.2 eV were found to be strongly polarization dependent. The peaks are assigned to the resonance excitations from the Si 1s to σ∗ pyz and σ∗ px orbitals localized at the Si–C and Si–Si bonds, respectively. Quantitative evaluation of the polarization dependence of the NEXAFS spectra revealed that the molecules are self-assembled on HOPG surface, and the backbones of the PDMS are oriented nearly parallel to the surface. The observed orientation is opposite to the previously observed results for PDMS on the other surfaces such as oxide (indium tin oxide and metal (polycrystalline copper. The flat-lying feature of PDMS observed only on HOPG surface is attributed to the interaction between CH bonds in PDMS and π orbitals in HOPG surface.

  6. Fluorescence and absorption spectroscopy for warm dense matter studies and ICF plasma diagnostics

    Science.gov (United States)

    Hansen, S. B.; Harding, E. C.; Knapp, P. F.; Gomez, M. R.; Nagayama, T.; Bailey, J. E.

    2018-05-01

    The burning core of an inertial confinement fusion (ICF) plasma produces bright x-rays at stagnation that can directly diagnose core conditions essential for comparison to simulations and understanding fusion yields. These x-rays also backlight the surrounding shell of warm, dense matter, whose properties are critical to understanding the efficacy of the inertial confinement and global morphology. We show that the absorption and fluorescence spectra of mid-Z impurities or dopants in the warm dense shell can reveal the optical depth, temperature, and density of the shell and help constrain models of warm, dense matter. This is illustrated by the example of a high-resolution spectrum collected from an ICF plasma with a beryllium shell containing native iron impurities. Analysis of the iron K-edge provides model-independent diagnostics of the shell density (2.3 × 1024 e/cm3) and temperature (10 eV), while a 12-eV red shift in Kβ and 5-eV blue shift in the K-edge discriminate among models of warm dense matter: Both shifts are well described by a self-consistent field model based on density functional theory but are not fully consistent with isolated-atom models using ad-hoc density effects.

  7. Study of sub band gap absorption of Sn doped CdSe thin films

    International Nuclear Information System (INIS)

    Kaur, Jagdish; Rani, Mamta; Tripathi, S. K.

    2014-01-01

    The nanocrystalline thin films of Sn doped CdSe at different dopants concentration are prepared by thermal evaporation technique on glass substrate at room temperature. The effect of Sn doping on the optical properties of CdSe has been studied. A decrease in band gap value is observed with increase in Sn concentration. Constant photocurrent method (CPM) is used to study the absorption coefficient in the sub band gap region. Urbach energy has been obtained from CPM spectra which are found to increase with amount of Sn dopants. The refractive index data calculated from transmittance is used for the identification of oscillator strength and oscillator energy using single oscillator model which is found to be 7.7 and 2.12 eV, 6.7 and 2.5 eV for CdSe:Sn 1% and CdSe:Sn 5% respectively

  8. An X-ray absorption spectroscopy study of the interactions of Ni2+ with yeast enolase.

    Science.gov (United States)

    Wang, S; Scott, R A; Lebioda, L; Zhou, Z H; Brewer, J M

    1995-05-15

    An x-ray absorption spectroscopy (XAS) study was carried out at pH 7.6 on solutions of Ni2+ and yeast enolase depleted of its physiological cofactor (Mg2+) in the presence or absence of substrate/product, the very strongly bound competitive inhibitor 2-phosphonoacetohydroxamate and Mg2+. Both "conformational" and "catalytic" Ni2+ are distorted octahedral in coordination, in agreement with several spectroscopic studies but in contrast to the coordination in the crystal at pH 6.0. The data are consistent with direct coordination of what must be the catalytic Ni2+ to the phosphate of the substrate, in agreement with some previous data but in disagreement with recent interpretations by other workers. The ligands around the metal ions obtained from the x-ray structure give simulated XAS spectra in good agreement with the observed spectra.

  9. X-ray absorption radiography for high pressure shock wave studies

    Science.gov (United States)

    Antonelli, L.; Atzeni, S.; Batani, D.; Baton, S. D.; Brambrink, E.; Forestier-Colleoni, P.; Koenig, M.; Le Bel, E.; Maheut, Y.; Nguyen-Bui, T.; Richetta, M.; Rousseaux, C.; Ribeyre, X.; Schiavi, A.; Trela, J.

    2018-01-01

    The study of laser compressed matter, both warm dense matter (WDM) and hot dense matter (HDM), is relevant to several research areas, including materials science, astrophysics, inertial confinement fusion. X-ray absorption radiography is a unique tool to diagnose compressed WDM and HDM. The application of radiography to shock-wave studies is presented and discussed. In addition to the standard Abel inversion to recover a density map from a transmission map, a procedure has been developed to generate synthetic radiographs using density maps produced by the hydrodynamics code DUED. This procedure takes into account both source-target geometry and source size (which plays a non negligible role in the interpretation of the data), and allows to reproduce transmission data with a good degree of accuracy.

  10. Study of sub band gap absorption of Sn doped CdSe thin films

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Jagdish; Rani, Mamta [Department of Physics, Panjab University, Chandigarh- 160014 (India); Tripathi, S. K., E-mail: surya@pu.ac.in [Centre of Advanced Study in Physics, Panjab University, Chandigarh- 160014 (India)

    2014-04-24

    The nanocrystalline thin films of Sn doped CdSe at different dopants concentration are prepared by thermal evaporation technique on glass substrate at room temperature. The effect of Sn doping on the optical properties of CdSe has been studied. A decrease in band gap value is observed with increase in Sn concentration. Constant photocurrent method (CPM) is used to study the absorption coefficient in the sub band gap region. Urbach energy has been obtained from CPM spectra which are found to increase with amount of Sn dopants. The refractive index data calculated from transmittance is used for the identification of oscillator strength and oscillator energy using single oscillator model which is found to be 7.7 and 2.12 eV, 6.7 and 2.5 eV for CdSe:Sn 1% and CdSe:Sn 5% respectively.

  11. Measurements of the Absorption by Auditorium SEATING—A Model Study

    Science.gov (United States)

    BARRON, M.; COLEMAN, S.

    2001-01-01

    One of several problems with seat absorption is that only small numbers of seats can be tested in standard reverberation chambers. One method proposed for reverberation chamber measurements involves extrapolation when the absorption coefficient results are applied to actual auditoria. Model seat measurements in an effectively large model reverberation chamber have allowed the validity of this extrapolation to be checked. The alternative barrier method for reverberation chamber measurements was also tested and the two methods were compared. The effect on the absorption of row-row spacing as well as absorption by small numbers of seating rows was also investigated with model seats.

  12. EPR and optical absorption studies of Cr3+ ions in potassium sodium dl-tartrate tetrahydrate

    International Nuclear Information System (INIS)

    Kripal, Ram; Singh, Pragya; Shukla, Santwana

    2011-01-01

    EPR spectra of Cr 3+ ions doped in potassium sodium dl-tartrate tetrahydrate single crystals are recorded at 77 K. The spin Hamiltonian and zero field parameters g, |D| and |E| are measured from the resonance lines obtained at various rotations of the magnetic field. The values obtained are: g x =1.9257±0.0002, g y =1.9720±0.0002, g z =2.0102±0.0002, |D|=313±2 (x10 -4 ) cm -1 and |E|=101±2 (x10 -4 ) cm -1 . From the results of EPR study, the site symmetry of Cr 3+ ion in the crystal is discussed. The optical absorption at room temperature is also studied. From the observed band positions, the crystal field splitting parameter (D q ) and the Racah inter-electronic repulsion parameters (B and C) are evaluated. The bonding parameters are obtained by correlating optical and EPR data and the nature of bonding in the crystal is discussed. -- Research Highlights: → EPR spectra of Cr 3+ ions doped in potassium sodium dl-tartrate tetrahydrate single crystals are done at 77 K. → The spin Hamiltonian and zero field parameters g, |D| and |E| are measured. From the results of EPR study, the site symmetry of Cr 3+ ion in the crystal is discussed. → The optical absorption at room temperature is also studied and the crystal field splitting parameter (D q ) as well as the Racah inter-electronic repulsion parameters (B and C) is evaluated. → The bonding parameters are obtained by correlating optical and EPR data and the nature of bonding in the crystal is discussed.

  13. Mn L2,3-edge X-ray absorption spectroscopic studies on charge-discharge mechanism of Li2MnO3

    International Nuclear Information System (INIS)

    Kubobuchi, Kei; Mogi, Masato; Imai, Hideto; Ikeno, Hidekazu; Tanaka, Isao; Mizoguchi, Teruyasu

    2014-01-01

    The redox reaction of Mn in Li 2 MnO 3 was studied by X-ray absorption spectroscopy and ab initio multiplet calculation. Associated with the de-intercalation of Li-ion, small but clear spectral changes were observed in Mn-L 2,3 X-ray absorption near edge structure (XANES). The systematic ab initio multiplet calculations of Mn-L 2,3 XANES revealed that the spectral changes in the experiment could not simply be ascribed to the change of the valency from Mn 4+ to Mn 5+ but can be explained well by the changes of local atomic structures around Mn 4+ due to the Li de-intercalation. Our results suggest that the electronic state of oxygen should change during charging in Li 2 MnO 3

  14. Study of electron-beam-evaporated MgO films using electron diffraction, optical absorption and cathodoluminescence

    Energy Technology Data Exchange (ETDEWEB)

    Aboelfotoh, M.O.; Ramsey, J.N.

    1982-05-21

    Reflection high energy electron diffraction, optical absorption and cathodoluminescence were used to study MgO films deposited onto fused silica, single-crystal silicon and LiF substrates at various temperatures. Results showed that some of the same optical absorption and emission bands observed in X- or UV-irradiated, additively colored or mechanically deformed MgO crystals were observed in evaporated MgO films. The peak positions and the relative peak intensities of the optical absorption and emission bands depended on the substrate temperature during film deposition as well as on the structure of the film. The effect of heating the films in air and vacuum on the optical absorption and emission bands is also discussed.

  15. EPR and optical absorption studies of Cu{sup 2+} doped L-histidinium dihydrogen phosphate–phosphoric acid single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Prabakaran, R.; Sheela, K. Juliet; Rosy, S. Margret [Department of Physics, Gandhigram Rural Institute—Deemed University, Gandhigram, Dindigul-624302, Tamilnadu (India); Radha Krishnan, S.; Shanmugam, V.M. [CSIR-Central Electrochemical Research Institute, Karaikudi-630006, Tamilnadu (India); Subramanian, P., E-mail: psmanian_gri@yahoo.com [Department of Physics, Gandhigram Rural Institute—Deemed University, Gandhigram, Dindigul-624302, Tamilnadu (India)

    2014-02-01

    The EPR spectra of Cu{sup 2+} in L-histidinium dihydrogen phosphate phosphoric acid at room temperature reveal the presence of two magnetically inequivalent Cu{sup 2+} sites in the lattice. The principal values of the g- and A-tensors indicate existence of rhombic symmetry around the Cu{sup 2+} ion. From the direction cosines of the principal values of the g- and A-tensors, the locations of Cu{sup 2+} in the lattice have been identified as substitutional sites. Optical absorption study shows four bands confirm the rhombic symmetry. Photoluminescence study also confirms the rhombic symmetry around the ions.

  16. Kinetic and Diagnostic Studies of Molecular Plasmas Using Laser Absorption Techniques

    International Nuclear Information System (INIS)

    Welzel, S; Rousseau, A; Davies, P B; Roepcke, J

    2007-01-01

    Within the last decade mid infrared absorption spectroscopy between 3 and 20 μm, known as Infrared Laser Absorption Spectroscopy (IRLAS) and based on tuneable semiconductor lasers, namely lead salt diode lasers, often called tuneable diode lasers (TDL), and quantum cascade lasers (QCL) has progressed considerably as a powerful diagnostic technique for in situ studies of the fundamental physics and chemistry of molecular plasmas. The increasing interest in processing plasmas containing hydrocarbons, fluorocarbons, organo-silicon and boron compounds has lead to further applications of IRLAS because most of these compounds and their decomposition products are infrared active. IRLAS provides a means of determining the absolute concentrations of the ground states of stable and transient molecular species, which is of particular importance for the investigation of reaction kinetics. Information about gas temperature and population densities can also be derived from IRLAS measurements. A variety of free radicals and molecular ions have been detected, especially using TDLs. Since plasmas with molecular feed gases are used in many applications such as thin film deposition, semiconductor processing, surface activation and cleaning, and materials and waste treatment, this has stimulated the adaptation of infrared spectroscopic techniques to industrial requirements. The recent development of QCLs offers an attractive new option for the monitoring and control of industrial plasma processes as well as for highly time-resolved studies on the kinetics of plasma processes. The aim of the present article is threefold: (i) to review recent achievements in our understanding of molecular phenomena in plasmas (ii) to report on selected studies of the spectroscopic properties and kinetic behaviour of radicals, and (iii) to describe the current status of advanced instrumentation for TDLAS in the mid infrared

  17. Experimental study of a thermochemical compressor for an absorption/compression hybrid cycle

    International Nuclear Information System (INIS)

    Ventas, R.; Vereda, C.; Lecuona, A.; Venegas, M.

    2012-01-01

    Highlights: ► Experimental study of a thermochemical compressor for absorption/compression cycle. ► Spray adiabatic absorber using NH 3 –LiNO 3 solution working fluid. ► It is able to operate between 57 and 110 °C varying concentration between 0.46 and 0.59. ► The increase of absorber pressure decreases the circulation ratio. ► The numerical model performed agrees with the experimental results. -- Abstract: An experimental study of a thermochemical compressor with ammonia–lithium nitrate solution as working fluid has been carried out. This compressor incorporates a single-pass adiabatic absorber and all the heat exchangers are of the plate type: absorber subcooler, generator and solution heat exchanger. The thermochemical compressor has been studied as part of a single-effect absorption chiller hybridized with an in-series low-pressure compression booster. The adiabatic absorber uses fog jet injectors. The generator hot water temperatures for the external driving flow are in the range of 57–110 °C and the absorber pressures range between 429 and 945 kPa. Experimental results are compared with a numerical model showing a high agreement. The performance of the thermochemical compressor, evaluated through the circulation ratio, improves for higher absorber pressures, indicating the potential of pressure boosting. For the same circulation ratio, the driving hot water inlet temperature decreases with the rise of the absorber pressure. The thermochemical compressor, based on an adiabatic absorber, can produce refrigerant with very low driving temperatures, between 57 and 70 °C, what is interesting for solar cooling applications and very low temperature residual heat recovery. Efficiencies and cooling power are offered when this hybrid thermochemical compressor is implemented in a chiller, showing the effect of different operating parameters.

  18. Reveal genes functionally associated with ACADS by a network study.

    Science.gov (United States)

    Chen, Yulong; Su, Zhiguang

    2015-09-15

    Establishing a systematic network is aimed at finding essential human gene-gene/gene-disease pathway by means of network inter-connecting patterns and functional annotation analysis. In the present study, we have analyzed functional gene interactions of short-chain acyl-coenzyme A dehydrogenase gene (ACADS). ACADS plays a vital role in free fatty acid β-oxidation and regulates energy homeostasis. Modules of highly inter-connected genes in disease-specific ACADS network are derived by integrating gene function and protein interaction data. Among the 8 genes in ACADS web retrieved from both STRING and GeneMANIA, ACADS is effectively conjoined with 4 genes including HAHDA, HADHB, ECHS1 and ACAT1. The functional analysis is done via ontological briefing and candidate disease identification. We observed that the highly efficient-interlinked genes connected with ACADS are HAHDA, HADHB, ECHS1 and ACAT1. Interestingly, the ontological aspect of genes in the ACADS network reveals that ACADS, HAHDA and HADHB play equally vital roles in fatty acid metabolism. The gene ACAT1 together with ACADS indulges in ketone metabolism. Our computational gene web analysis also predicts potential candidate disease recognition, thus indicating the involvement of ACADS, HAHDA, HADHB, ECHS1 and ACAT1 not only with lipid metabolism but also with infant death syndrome, skeletal myopathy, acute hepatic encephalopathy, Reye-like syndrome, episodic ketosis, and metabolic acidosis. The current study presents a comprehensible layout of ACADS network, its functional strategies and candidate disease approach associated with ACADS network. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Transient absorption microscopy studies of energy relaxation in graphene oxide thin film.

    Science.gov (United States)

    Murphy, Sean; Huang, Libai

    2013-04-10

    Spatial mapping of energy relaxation in graphene oxide (GO) thin films has been imaged using transient absorption microscopy (TAM). Correlated AFM images allow us to accurately determine the thickness of the GO films. In contrast to previous studies, correlated TAM-AFM allows determination of the effect of interactions of GO with the substrate and between stacked GO layers on the relaxation dynamics. Our results show that energy relaxation in GO flakes has little dependence on the substrate, number of stacked layers, and excitation intensity. This is in direct contrast to pristine graphene, where these factors have great consequences in energy relaxation. This suggests intrinsic factors rather than extrinsic ones dominate the excited state dynamics of GO films.

  20. Transient absorption microscopy studies of energy relaxation in graphene oxide thin film

    International Nuclear Information System (INIS)

    Murphy, Sean; Huang, Libai

    2013-01-01

    Spatial mapping of energy relaxation in graphene oxide (GO) thin films has been imaged using transient absorption microscopy (TAM). Correlated AFM images allow us to accurately determine the thickness of the GO films. In contrast to previous studies, correlated TAM–AFM allows determination of the effect of interactions of GO with the substrate and between stacked GO layers on the relaxation dynamics. Our results show that energy relaxation in GO flakes has little dependence on the substrate, number of stacked layers, and excitation intensity. This is in direct contrast to pristine graphene, where these factors have great consequences in energy relaxation. This suggests intrinsic factors rather than extrinsic ones dominate the excited state dynamics of GO films. (paper)

  1. Study on the surface hydroxyl group on solid breeding materials by infrared absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Satoru; Taniguchi, Masaki [Tokyo Univ. (Japan). Faculty of Engineering

    1996-10-01

    Hydroxyl groups on the surface of Li{sub 2}O were studied by using a diffuse reflectance method with Fourier transform infrared absorption spectroscopy at high temperature up to 973K under controlled D{sub 2}O or D{sub 2} partial pressure. It was found that hydroxyl groups could exist on Li{sub 2}O surface up to 973K under Ar atmosphere. Under D{sub 2}O containing atmosphere, only the sharp peak at 2520cm{sup -1} was observed at 973K in the O-D stretching vibration region. Below 973K, multiple peaks due to the surface -OD were observed and they showed different behavior with temperature or atmosphere. Multiple peaks mean that surface is not homogeneous for D{sub 2}O adsorption. Assignment of the observed peaks to the surface bonding structure was also discussed. (author)

  2. Extended x-ray absorption fine structure: Studies of zinc-neutralized sulfonated polystyrene ionomers

    International Nuclear Information System (INIS)

    Ding, Y.S.; Yarusso, D.J.; Pan, H.K.D.; Cooper, S.L.

    1984-01-01

    Extended x-ray absorption fine structure (EXAFS) measurements were performed on a series of zinc-neutralized sulfonated polystyrene ionomers and the local structure around the zinc atom was determined. An interference effect in the EXAFS signal between sulfur and oxygen atoms was found to be significant in these materials. A model for the local structure in the zinc-neutralized sulfonated polystyrene ionomers is proposed which suggests a highly ordered tetrahedral coordination of oxygen around the zinc atoms at a distance of 1.97 +- 0.02 A. In addition there are four sulfur atoms and four oxygen atoms at a distance of 3.15 +- 0.05 A. No zinc-zinc coordination within 5 A was detected in this study

  3. Theoretical study on the effect of operating conditions on performance of absorption refrigeration system

    Energy Technology Data Exchange (ETDEWEB)

    Kaynakli, Omer; Kilic, Muhsin [Uludag University, Faculty of Engineering and Architecture, Department of Mechanical Engineering, TR-16059, Bursa (Turkey)

    2007-02-15

    In this study, a detailed thermodynamic analysis of the water/lithium bromide absorption refrigeration cycle is performed. The influences of operating temperature and effectiveness of heat exchanger on the thermal loads of components, coefficients of performance (COP{sub c}, COP) and efficiency ratio ({eta}) are investigated. It is concluded that the COP{sub c} and COP values increase with increasing generator and evaporator temperatures but decrease with increasing condenser and absorber temperatures. The {eta} value varies with these temperatures. Also, the effects of solution and refrigerant heat exchangers on the performance, efficiency ratio of the system and fluid temperatures are compared. As a result, it is found that the solution heat exchanger (SHE) has more effect on the investigated parameters than the refrigerant heat exchanger (RHE). While the SHE increases the COP value up to a maximum 44%, the RHE has an effect of only 2.8%. (author)

  4. Hydrogen absorption study of Ti-based alloys performed by melt-spinning

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, R.M.; Lemus, L.F.; Santos, D.S. dos, E-mail: rafaella@metalmat.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (PEMM/COPPEP/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Metalurgica e de Materiais

    2013-11-01

    The hydrogen absorption and desorption of Ti{sub 53}Zr{sub 27}Ni{sub 20} icosahedral quasicrystal (ICQ) and Ti{sub 50}Ni{sub 50} shape memory alloy (SMA) melt-spun ribbons was studied. Samples were exposed to hydrogen gas at 623 K and 4 MPa for 1000 minutes. The total capacity of hydrogen obtained for Ti{sub 53}Zr{sub 27}Ni{sub 20} and Ti{sub 50}Ni{sub 50} was 3.2 and 2.4 wt. % respectively. The Thermal Desorption Spectrometry (TDS) of the hydrogenated alloys shows that both alloys start to desorb hydrogen around 750 K. X-ray diffraction (XRD) patterns, performed after hydrogenation, indicate a complete amorphization of the Ti{sub 53}Zr{sub 27}Ni{sub 20} i-phase alloy, while the Ti{sub 50}Ni{sub 50} alloy remained crystalline after hydride formation. (author)

  5. Study of laser radar system using the differential absorption method for detection of air pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Inomata, H; Igarashi, T

    1975-11-01

    A laser radar system using the differential absorption method for remote measurement of atmospheric NO/sub 2/ and SO/sub 2/ is studied. A simultaneous two-wavelength dye laser for the transmitter and a simultaneous two-wavelength signal processer for the receiver are developed. In using this technique, one laser shot allows the determination of NO/sub 2/ concentrations with an uncertainty equivalent to 44 ppM times the range interval (in meters). It seems that the technique is most promising for a range-resolved measurement of ambient molecular pollutants, since it has the advantage of canceling the effect of atmospheric variation in a measurement when atmospheric aerosols are used as a distributed reflector.

  6. Supramolecular fullerene/porphyrin charge transfer interaction studied by absorption spectrophotometric method

    Science.gov (United States)

    Mukherjee, Partha; Bhattacharya (Banerjee), Shrabanti; Nayak, Sandip K.; Chattopadhyay, Subrata; Bhattacharya, Sumanta

    2009-06-01

    A detailed UV-Vis spectrometric and thermodynamic studies were done to look insight into the nature of molecular interactions of the electron donor-acceptor complexes of C60 and C70 with 5,10,15,20-tetrakis(octadecyloxyphenyl)-21H,23H-porphyrin (1) in chloroform and toluene. Charge transfer (CT) absorption bands were located in the visible region and vertical ionization potential of 1 was determined utilizing CT transition energy. Low values of oscillator and transition dipole strengths suggested that the complexes were almost of neutral character in ground states. The high binding constant value for the C70-1 complex indicated high selectivity of 1 molecule towards C70. Experimental as well as theoretically determined of enthalpies of formation value substantiated the trend in K values for fullerene-1 complexes.

  7. Biexcitons in π-conjugated oligomers: Intensity-dependent femtosecond transient-absorption study

    Science.gov (United States)

    Klimov, V. I.; McBranch, D. W.; Barashkov, N.; Ferraris, J.

    1998-09-01

    We report femtosecond transient-absorption (TA) studies of a five-ring oligomer of poly(para-phenylene vinylene) prepared in two different forms: solid-state films and dilute solutions. At high pump fluences, in both types of samples, we observe generation of two-exciton states, which are detected by the evolution of TA spectra and dynamics with increasing pump intensity. In solutions, double excitation of molecules results in the formation of stable biexcitons with enhanced oscillator strength, leading to an increased efficiency of the radiative decay and a superlinear pump dependence of the stimulated emission. In solid-state samples, the two-exciton states are unstable and decay on the subpicosecond time scale due to ultrafast charge transfer, accompanied by generation of interchain excitons.

  8. Biexcitons in {pi}-conjugated oligomers: Intensity-dependent femtosecond transient-absorption study

    Energy Technology Data Exchange (ETDEWEB)

    Klimov, V.I.; McBranch, D.W. [Chemical Science and Technology Division, CST-6, Mail Stop J585, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Barashkov, N.; Ferraris, J. [Chemistry Department, University of Texas, Dallas, Texas 75083 (United States)

    1998-09-01

    We report femtosecond transient-absorption (TA) studies of a five-ring oligomer of poly({ital para}-phenylene vinylene) prepared in two different forms: solid-state films and dilute solutions. At high pump fluences, in both types of samples, we observe generation of two-exciton states, which are detected by the evolution of TA spectra and dynamics with increasing pump intensity. In solutions, double excitation of molecules results in the formation of stable biexcitons with enhanced oscillator strength, leading to an increased efficiency of the radiative decay and a superlinear pump dependence of the stimulated emission. In solid-state samples, the two-exciton states are unstable and decay on the subpicosecond time scale due to ultrafast charge transfer, accompanied by generation of interchain excitons. {copyright} {ital 1998} {ital The American Physical Society}

  9. Picosecond absorption studies of photoinduced charge separation in polyelectrolyte bound aromatic chromophores

    Science.gov (United States)

    Shand, M. A.; Rodgers, M. A. J.; Webber, S. E.

    1991-02-01

    Picosecond absorption studies of photoinduced electron transfer between aromatic chromophores bound to polymethacrylic acid (P) and methylviologen (MV 2+ have been carried out in aqueous solution. The diphenylanthracene copolymer/viologen system at pH 2.8 shows the corresponding redox products DPA + rad and MV + rad arising from the singlet state of DPA with a forward rate constant of electron transfer of 2.6 × 10 9 s -1. At pH 9.0 the quenching of the S 1 state of DPA occurs with no charge separated products being observed. The pyrene copolymer shows no evidence of charge separated products at any pH in the range 2.8-9.0. It is proposed that the differences in the radical pair kinetics arise from differences in the degree of binding of the ground state complexes formed by the donor and acceptor species.

  10. Experimental studies of solar heat pipe used to operate absorption chiller in conditions of Vietnam

    Energy Technology Data Exchange (ETDEWEB)

    Hiep, Le Chi [Ho Chi Minh City Univ. of Tech., Ho Chi Minh City (Viet Nam); Quoc, Hoang An [Ho Chi Minh City Univ. of Tech. Education, Ho Chi Minh City (Viet Nam); Hung, Hoang Duong [Danang Univ. of Tech., Danang City (Viet Nam)

    2008-07-01

    Several models of solar heat pipe have been fabricated and tested. The experiments show that the flat plate model could be used to operate absorption chiller in the climate of southern part of Vietnam. Two main advantages of the selected solar heat pipe are low cost and easy fabrication at local conditions. It is expected that the selected solar heat pipe could attract attention of the community to develop the application of solar energy in Vietnam. Based on the current demand, the paper presents the experimental studies of the first generation of low cost solar heat pipe. The paper also discusses the ability of application of solar air conditioning in Vietnam and recommends the suitable diagram mixing solar energy with other heat source to operate stably the system. (orig.)

  11. Electronic topological transition in zinc under pressure: An x-ray absorption spectroscopy study

    International Nuclear Information System (INIS)

    Aquilanti, G.; Trapananti, A.; Pascarelli, S.; Minicucci, M.; Principi, E.; Liscio, F.; Twarog, A.

    2007-01-01

    Zinc metal has been studied at high pressure using x-ray absorption spectroscopy. In order to investigate the role of the different degrees of hydrostaticity on the occurrence of structural anomalies following the electronic topological transition, two pressure transmitting media have been used. Results show that the electronic topological transition, if it exists, does not induce an anomaly in the local environment of compressed Zn as a function of hydrostatic pressure and any anomaly must be related to a loss of hydrostaticity of the pressure transmitting medium. The near-edge structures of the spectra, sensitive to variations in the electronic density of states above the Fermi level, do not show any evidence of electronic transition whatever pressure transmitting medium is used

  12. Composite population kernels in ytterbium-buffer collisions studied by means of laser-saturated absorption

    International Nuclear Information System (INIS)

    Zhu, X.

    1986-01-01

    We present a systematic study of composite population kernels for 174 Yb collisions with He, Ar, and Xe buffer gases, using laser-saturation spectroscopy. 174 Yb is chosen as the active species because of the simple structure of its 1 S 0 - 3 P 1 resonance transition (lambda = 556 nm). Elastic collisions are modeled by means of a composite collision kernel, an expression of which is explicitly derived based on arguments of a hard-sphere potential and two-category collisions. The corresponding coupled population-rate equations are solved by iteration to obtain an expression for the saturated-absorption line shape. This expression is fit to the data to obtain information about the composite kernel, along with reasonable values for other parameters. The results confirm that a composite kernel is more general and realistic than a single-component kernel, and the generality in principle and the practical necessity of the former are discussed

  13. Kinetic and diagnostic studies of molecular plasmas using laser absorption techniques

    NARCIS (Netherlands)

    Welzel, S.; Rousseau, A.; Davies, P.B.; Röpcke, J.

    2007-01-01

    Within the last decade mid infrared absorption spectroscopy between 3 and 20 µm, known as Infrared Laser Absorption Spectroscopy (IRLAS) and based on tuneable semiconductor lasers, namely lead salt diode lasers, often called tuneable diode lasers (TDL), and quantum cascade lasers (QCL) has

  14. The study of CO2 absorption intensification using porous media material in aqueous AMP solution

    Directory of Open Access Journals (Sweden)

    Min Xiao

    2018-03-01

    Full Text Available In this work, the performance of CO2 absorption into aqueous 2-amino-2-methyl-propanol (AMP solution was investigated by measuring the amount of CO2 in the liquid phase during CO2 absorption process to identify initial CO2 absorption rate. Then, the porous media material named as MCM41 was introduced into the amine solution to test its influence on CO2 absorption. It was found that MCM41 increased initial CO2 absorption rate and enhanced CO2 absorption process. The physico-chemical properties of MCM41 were characterized in terms of specific surface area, average pore diameter, total pore volume and chemical properties, the amount of acidic sites and the Brϕnsted/Lewis (B/L acid sites ratio. Results showed that MCM41 was a type of Lewis acid catalyst with large specific surface area and pore volume. In addition, the pKa of AMP solution with and without MCM41 was obtained using acid titration technology to help understand the effect brought by MCM41. A mechanism illustrating how MCM41 increases the CO2 absorption rate of the AMP solution was proposed and demonstrated that MCM41 is a potential material for enhancing CO2 absorption.

  15. A study of luminescence and absorption spectra of GaP

    International Nuclear Information System (INIS)

    Mansour, H.M.M.; Abdel Wahab, S.M.

    1994-08-01

    Experimental luminescence and absorption spectra of GaP at room temperature are presented. A theoretical analysis has been performed on the luminescence and absorption spectra in GaP. The experimental data are in good agreement with the theoretical results. (author). 18 refs, 8 figs

  16. The Driving Forces of Subsidiary Absorptive Capacity

    DEFF Research Database (Denmark)

    Schleimer, Stephanie C.; Pedersen, Torben

    2013-01-01

    The study investigates how a multinational corporation (MNC) can promote the absorptive capacity of its subsidiaries. The focus is on what drives the MNC subsidiary's ability to absorb marketing strategies that are initiated by the MNC parent, as well as how the subsidiary enacts on this absorptive...... as a purposeful response to this dual embeddedness. An analysis of marketing strategy absorptions undertaken by 213 subsidiaries reveals that MNCs can assist their subsidiaries to compete in competitive and dynamic focal markets by forming specific organizational mechanisms that are conducive to the development...

  17. Operando Soft X-ray Absorption Spectroscopic Study on a Solid Oxide Fuel Cell Cathode during Electrochemical Oxygen Reduction.

    Science.gov (United States)

    Nakamura, Takashi; Oike, Ryo; Kimura, Yuta; Tamenori, Yusuke; Kawada, Tatsuya; Amezawa, Koji

    2017-05-09

    An operando soft X-ray absorption spectroscopic technique, which enabled the analysis of the electronic structures of the electrode materials at elevated temperature in a controlled atmosphere and electrochemical polarization, was established and its availability was demonstrated by investigating the electronic structural changes of an La 2 NiO 4+δ dense-film electrode during an electrochemical oxygen reduction reaction. Clear O K-edge and Ni L-edge X-ray absorption spectra could be obtained below 773 K under an atmospheric pressure of 100 ppm O 2 /He, 0.1 % O 2 /He, and 1 % O 2 /He gas mixtures. Considerable spectral changes were observed in the O K-edge X-ray absorption spectra upon changing the PO2 and application of electrical potential, whereas only small spectral changes were observed in Ni L-edge X-ray absorption spectra. A pre-edge peak of the O K-edge X-ray absorption spectra, which reflects the unoccupied partial density of states of Ni 3d-O 2p hybridization, increased or decreased with cathodic or anodic polarization, respectively. The electronic structural changes of the outermost orbital of the electrode material due to electrochemical polarization were successfully confirmed by the operando X-ray absorption spectroscopic technique developed in this study. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Theoretical modeling of the spectroscopic absorption properties of luciferin and oxyluciferin: A critical comparison with recent experimental studies

    Energy Technology Data Exchange (ETDEWEB)

    Anselmi, Massimiliano, E-mail: m.anselmi@caspur.it [Department of Chemistry, University of Rome ' La Sapienza' , P.le Aldo Moro 5, 00185 Rome (Italy); Marocchi, Simone [Department of Chemistry, University of Rome ' La Sapienza' , P.le Aldo Moro 5, 00185 Rome (Italy); Aschi, Massimiliano [Department of Chemistry, Chemical Engineering and Materials, University of L' Aquila, Via Vetoio (Coppito 1), 67100 Coppito, L' Aquila (Italy); Amadei, Andrea [Department of Chemistry, University of Rome ' Tor Vergata' , Via della Ricerca Scientifica 1, 00133 Rome (Italy)

    2012-01-02

    Highlights: Black-Right-Pointing-Pointer The calculated absorption spectra were compared with experimental data. Black-Right-Pointing-Pointer Shapes and absorption maxima were reproduced for luciferin and oxyluciferin spectra. Black-Right-Pointing-Pointer The effect of the solvent largely changes the electronic transition probabilities. Black-Right-Pointing-Pointer Higher excitations provide an important contribution to the main absorption peak. - Abstract: Firefly luciferin and its oxidated form, oxyluciferin, are two heterocyclic compounds involved in the enzymatic reaction, catalyzed by redox proteins called luciferases, which provides the bioluminescence in a wide group of arthropods. Whereas the electronic absorption spectra of D-luciferin in water at different pHs are known since 1960s, only recently reliable experimental electronic spectra of oxyluciferin have become available. In addition oxyluciferin is involved in a triple chemical equilibria (deprotonation of the two hydroxyl groups and keto-enol tautomerism of the 4-hydroxythiazole ring), that obligates to select during an experiment a predominant species, tuning pH or solvent polarity besides introducing chemical modifications. In this study we report the absorption spectra of luciferin and oxyluciferin in each principal chemical form, calculated by means of perturbed matrix method (PMM), which allowed us to successfully introduce the effect of the solvent on the spectroscopic absorption properties, and compare the result with available experimental data.

  19. Novel atomic absorption spectrometric and rapid spectrophotometric methods for the quantitation of paracetamol in saliva: application to pharmacokinetic studies.

    Science.gov (United States)

    Issa, M M; Nejem, R M; El-Abadla, N S; Al-Kholy, M; Saleh, Akila A

    2008-01-01

    A novel atomic absorption spectrometric method and two highly sensitive spectrophotometric methods were developed for the determination of paracetamol. These techniques based on the oxidation of paracetamol by iron (III) (method I); oxidation of p-aminophenol after the hydrolysis of paracetamol (method II). Iron (II) then reacts with potassium ferricyanide to form Prussian blue color with a maximum absorbance at 700 nm. The atomic absorption method was accomplished by extracting the excess iron (III) in method II and aspirates the aqueous layer into air-acetylene flame to measure the absorbance of iron (II) at 302.1 nm. The reactions have been spectrometrically evaluated to attain optimum experimental conditions. Linear responses were exhibited over the ranges 1.0-10, 0.2-2.0 and 0.1-1.0 mug/ml for method I, method II and atomic absorption spectrometric method, respectively. A high sensitivity is recorded for the proposed methods I and II and atomic absorption spectrometric method value indicate: 0.05, 0.022 and 0.012 mug/ml, respectively. The limit of quantitation of paracetamol by method II and atomic absorption spectrometric method were 0.20 and 0.10 mug/ml. Method II and the atomic absorption spectrometric method were applied to demonstrate a pharmacokinetic study by means of salivary samples in normal volunteers who received 1.0 g paracetamol. Intra and inter-day precision did not exceed 6.9%.

  20. Parametric study of an absorption refrigeration machine using advanced exergy analysis

    International Nuclear Information System (INIS)

    Gong, Sunyoung; Goni Boulama, Kiari

    2014-01-01

    An advanced exergy analysis of a water–lithium bromide absorption refrigeration machine was conducted. For each component of the machine, the proposed analysis quantified the irreversibility that can be avoided and the irreversibility that is unavoidable. It also identified the irreversibility originating from inefficiencies within the component and the irreversibility that does not originate from the operation of the considered component. It was observed that the desorber and absorber concentrated most of the exergy destruction. Furthermore, the exergy destruction at these components was found to be dominantly endogenous and unavoidable. A parametrical study has been presented discussing the sensitivity of the different performance indicators to the temperature at which the heat source is available, the temperature of the refrigerated environment, and the temperature of the cooling medium used at the condenser and absorber. It was observed that the endogenous avoidable exergy destruction at the desorber, i.e. the portion of the desorber irreversibility that could be avoided by improving the design and operation of the desorber, decreased when the heat source or the temperature at which the cooling effect was generated increased, and it decreased when the heat sink temperature increased. The endogenous avoidable exergy destruction at the absorber displayed the same variations, though it was observed to be less affected by the heat source temperature. Contrary to the aforementioned two components, the exergy destruction at the evaporator and condenser were dominantly endogenous and avoidable, with little sensitivity to the cycle operating parameters. - Highlights: • Endogenous, exogenous, avoidable and unavoidable irreversibilities were calculated for a water–LiBr absorption machine. • Overall, desorber and absorber concentrated most of the exergy destruction of the cycle. • The exergy destruction was mainly endogenous and unavoidable for the desorber and

  1. Polarized-x-ray-absorption studies of graphite intercalated-bromine compounds

    International Nuclear Information System (INIS)

    Feldman, J.L.; Elam, W.T.; Ehrlich, A.C.; Skelton, E.F.; Dominguez, D.D.; Chung, D.D.L.; Lytle, F.W.

    1986-01-01

    Details of both results and data analysis are given in the case of our polarized-x-ray-absorption experiments, using synchrotron radiation, on highly oriented pyrolytic graphite (HOPG)--based and graphite-fiber-based residual-bromine intercalation compounds. The effective angle which nearest-neighbor Br pairs make with crystallite graphite planes in some of these compounds, which was stated to be approx.20 0 in an earlier article, is shown to be 16X(de +- 4X(de: both Br-Br extended x-ray-absorption fine structure (EXAFS) and white-line features of the data are the basis of this result. We have also found that, whereas spherical averages of the areas under white-line spectra are independent of the choice of the material among all samples studied (including Br 2 vapor), differences in similarly spherically averaged Br-Br EXAFS amplitudes are evident, especially between Br 2 vapor and Br-graphite samples. We show that the latter differences which correspond to a coordination number less than one in Br-graphite are not due to either Gaussian or non-Gaussian (up to k 4 terms) Debye-Waller effects. In addition, we discuss the extraction of Br-C EXAFS and present results of model calculations of Br-C EXAFS, where several different structural models for the Br sites are considered. We also discuss thermal effects and their relation to known Br sublattice phase-transition behavior, based on our measurements at room temperature, 360 K, and 400 K

  2. Studies of electron-hole recombination processes at deep levels in GaAs and GaP by means of transient optical absorption spectroscopy

    International Nuclear Information System (INIS)

    Sugiyama, T.; Ishikawa, Y.; Tanimura, K.; Hayashi, Y.; Itoh, N.

    1989-01-01

    Studies of recombination processes by means of transient optical absorption (TOA) spectroscopy in GaAs and GaP are reviewed. It is pointed out that the technique can reveal production of excited states having long lifetimes and of non-luminescent metastable states. Two distinct recombination processes in GaAs containing EL2 defects are discussed: one is at the metastable EL2 defects, accompanied with transformation to the EL2 defects and the other is at deep acceptors through pair recombination. (author) 11 refs., 2 figs

  3. Applications of isotopes in plants for the study of absorption and transportation of mineral elements

    International Nuclear Information System (INIS)

    Jooste, J.H.

    1981-01-01

    The use of radioisotopes is illustrated by various experiments in plant nutrition. Firstly, the foliar uptake of Zn in fruit trees is discussed. Secondly, the foliar uptake of Fe is compared to the root absorption of a bean plant. Thirdly, there is a comparison of the absorption of the Cl-ion by the roots, leaves and flowers of the petunia. Na-absorption by the non-salt resistant bean plant as well as transportation rate in the bast and xylem are discussed shortly

  4. Small-bowel absorption of D-tagatose and related effects on carbohydrate digestibility: an ileostomy study.

    Science.gov (United States)

    Normén, L; Laerke, H N; Jensen, B B; Langkilde, A M; Andersson, H

    2001-01-01

    The ketohexose D-tagatose is a new sweetener with a low energy content. This low energy content may be due to either low absorption of the D-tagatose or decreased absorption of other nutrients. The aims of this study were to measure the excretion of D-tagatose from the human small bowel, to calculate the apparent absorption of D-tagatose, and to study the effects of D-tagatose on the small-bowel excretion of other carbohydrates. A controlled diet was served for 2 periods of 2 d during 3 consecutive weeks to 6 ileostomy subjects. In one of the periods, 15 g D-tagatose was added to the diet daily. Duplicate portions of the diet and ileostomy effluents were freeze-dried and analyzed to calculate the apparent net absorption of D-tagatose and carbohydrates. Median D-tagatose excretion was 19% (range: 12-31%), which corresponded to a calculated apparent absorption of 81% (69-88%). Of the total amount of D-tagatose excreted [2.8 g (1.7-4.4 g)], 60% (8-88%) was excreted within 3 h. Between 3 and 5 h, 32% (11-82%) was excreted. Excretion of wet matter increased by 41% (24-52%) with D-tagatose ingestion. Sucrose and D-glucose excretion increased to a small extent, whereas no significant changes were found in the excretion of dry matter, energy, starch, or D-fructose. The apparent absorption of 15 g D-tagatose/d was 81%. D-Tagatose had only a minor influence on the apparent absorption of other nutrients.

  5. Optical absorption study of radiation and thermal effects in Brazilian samples of spodumene

    International Nuclear Information System (INIS)

    Isotani, S.; Fujii, A.T.; Antonini, R.; Furtado, W.

    1988-03-01

    A detailed analysis of the optical absorption spectra of five varieties of Brazilian spodumene is presented. The samples were submitted to heat treatments and irradiated with gamma rays, x radiation, electrons and ultraviolet light. (M.C.K.) [pt

  6. On the nature of solvatochromic effect: The riboflavin absorption spectrum as a case study

    Science.gov (United States)

    Daidone, Isabella; Amadei, Andrea; Aschi, Massimiliano; Zanetti-Polzi, Laura

    2018-03-01

    We present here the calculation of the absorption spectrum of riboflavin in acetonitrile and dimethyl sulfoxide using a hybrid quantum/classical approach, namely the perturbed matrix method, based on quantum mechanical calculations and molecular dynamics simulations. The calculated spectra are compared to the absorption spectrum of riboflavin previously calculated in water and to the experimental spectra obtained in all three solvents. The experimentally observed variations in the absorption spectra upon change of the solvent environment are well reproduced by the calculated spectra. In addition, the nature of the excited states of riboflavin interacting with different solvents is investigated, showing that environment effects determine a recombination of the gas-phase electronic states and that such a recombination is strongly affected by the polarity of the solvent inducing significant changes in the absorption spectra.

  7. Effect of the three-dimensional microstructure on the sound absorption of foams: A parametric study.

    Science.gov (United States)

    Chevillotte, Fabien; Perrot, Camille

    2017-08-01

    The purpose of this work is to systematically study the effect of the throat and the pore sizes on the sound absorbing properties of open-cell foams. The three-dimensional idealized unit cell used in this work enables to mimic the acoustical macro-behavior of a large class of cellular solid foams. This study is carried out for a normal incidence and also for a diffuse field excitation, with a relatively large range of sample thicknesses. The transport and sound absorbing properties are numerically studied as a function of the throat size, the pore size, and the sample thickness. The resulting diagrams show the ranges of the specific throat sizes and pore sizes where the sound absorption grading is maximized due to the pore morphology as a function of the sample thickness, and how it correlates with the corresponding transport parameters. These charts demonstrate, together with typical examples, how the morphological characteristics of foam could be modified in order to increase the visco-thermal dissipation effects.

  8. A flexible gas flow reaction cell for in situ x-ray absorption spectroscopy studies

    Energy Technology Data Exchange (ETDEWEB)

    Kroner, Anna B., E-mail: anna.kroner@diamond.ac.uk; Gilbert, Martin; Duller, Graham; Cahill, Leo; Leicester, Peter; Woolliscroft, Richard; Shotton, Elizabeth J. [Diamond Light Source Ltd., Diamond House, Harwell Science and Innovation Campus, Chilton, Oxfordshire, OX110DE (United Kingdom); Mohammed, Khaled M. H. [UK Catalysis Hub, Research Complex at Harwell, Rutherford Appleton Laboratory, Chilton, Oxfordshire, OX110FA (United Kingdom); School of Chemistry, University of Southampton, Southampton, SO17 1BJ (United Kingdom)

    2016-07-27

    A capillary-based sample environment with hot air blower and integrated gas system was developed at Diamond to conduct X-ray absorption spectroscopy (XAS) studies of materials under time-resolved, in situ conditions. The use of a hot air blower, operating in the temperature range of 298-1173 K, allows introduction of other techniques e.g. X-ray diffraction (XRD), Raman spectroscopy for combined techniques studies. The flexibility to use either quartz or Kapton capillaries allows users to perform XAS measurement at energies as low as 5600 eV. To demonstrate performance, time-resolved, in situ XAS results of Rh catalysts during the process of activation (Rh K-edge, Ce L{sub 3}-edge and Cr K-edge) and the study of mixed oxide membrane (La{sub 0.6}Sr{sub 0.4}Co{sub 0.2}Fe{sub 0.8}O{sub 3−δ}) under various partial oxygen pressure conditions are described.

  9. Non-invasive gas monitoring in newborn infants using diode laser absorption spectroscopy: a case study

    Science.gov (United States)

    Lundin, Patrik; Svanberg, Emilie K.; Cocola, Lorenzo; Lewander, Märta; Andersson-Engels, Stefan; Jahr, John; Fellman, Vineta; Svanberg, Katarina; Svanberg, Sune

    2012-03-01

    Non-invasive diode laser spectroscopy was, for the first time, used to assess gas content in the intestines and the lungs of a new-born, 4 kg, baby. Two gases, water vapor and oxygen, were studied with two low-power tunable diode lasers, illuminating the surface skin tissue and detecting the diffusely emerging light a few centimeters away. The light, having penetrated into the tissue, had experienced absorption by gas located in the lungs and in the intestines. Very distinct water vapor signals were obtained from the intestines while imprint from oxygen was lacking, as expected. Detectable, but minor, signals of water vapor were also obtained from the lungs, illuminating the armpit area and detecting below the collar bone. Water vapor signals were seen but again oxygen signals were lacking, now due to the difficulties of penetration of the oxygen probing light into the lungs of this full-term baby. Ultra-sound images were obtained both from the lungs and from the stomach of the baby. Based on dimensions and our experimental findings, we conclude, that for early pre-term babies, also oxygen should be detectable in the lungs, in addition to intestine and lung detection of water vapor. The present paper focuses on the studies of the intestines while the lung studies will be covered in a forthcoming paper.

  10. Ex-vivo absorption study of lysine R-lipoate salt, a new pharmaceutical form of R-ALA.

    Science.gov (United States)

    Amenta, Francesco; Buccioni, Michela; Ben, Diego Dal; Lambertucci, Catia; Navia, Aleix Martí; Ngouadjeu Ngnintedem, Michael A; Ricciutelli, Massimo; Spinaci, Andrea; Volpini, Rosaria; Marucci, Gabriella

    2018-06-15

    Alpha-lipoic acid (ALA) oral supplements were used in many pathologies associated with increased oxidative stress. Although only R-ALA is considered the biologically active form, R,S-ALA is used in therapeutic applications even showing poor water solubility. The aim of this work was to study the absorption and transport mechanism across the intestinal barrier of new R-ALA stable and water soluble form, consisting in the lysine R-ALA salt, in presence and absence of specific inhibitors of Na + /multivitamin (SMVT) and monocarboxylic acids (MCT). The absorption of a new ALA form was investigated at rat everted sacs in comparison with R-ALA, S-ALA, and R,S-ALA. Results showed that duodenum is the best portion of intestine for ALA forms absorption. The absorption percentage of R-ALA, S-ALA, R,S-ALA, and lysine R-ALA salt was 66%, 43%, 55%, and 70%, respectively. The modest effect of the SMVT inhibitor biotin demonstrated that this transporter system is not principally involved in the absorption of lysine R-lipoate salt across the rat intestinal barrier. On the contrary, the MCT inhibitor octanoic acid significantly reduced the transport of this salt, whit an absorption decrease of R-ALA and lysine R-lipoate salt of 28% and 24%, respectively. Since the highest concentration of these inhibitors did not completely inhibit the absorption of lysine R-lipoate salt, other transport mechanisms probably operate for its intracellular delivery. The new form of ALA, lysine R-lipoate salt, was the most absorbed respect to the other ALA forms demonstrating that this compound is more suitable for oral administration. This new salt could represent a promising candidate for ALA oral supplementation. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. Infrared absorption spectroscopic study of Nd 3+ substituted Zn–Mg ...

    Indian Academy of Sciences (India)

    Compositions of polycrystalline ZnMg1-Fe2–NdO4 ( = 0.00, 0.20, 0.40, 0.60, 0.80 and 1.00; = 0.00, 0.05 and 0.10) ferrites were prepared by standard ceramic method and characterized by X-ray diffraction, scanning electron microscopy and infrared absorption spectroscopy. Far infrared absorption spectra show ...

  12. Increasing Absorptive Capacity to Improve Internal and External Knowledge Transfer in Multinational Companies: A Multiple Case Study Approach

    Directory of Open Access Journals (Sweden)

    Béla-Gergely RÁCZ

    2016-12-01

    Full Text Available This study investigates how the absorptive capacity could be increased to improve internal and external knowledge transfer in subsidiaries of multinational companies. We look at the way in which the literature on absorptive capacity has evolved, and how it links the internal and external knowledge transfer. Based on 3 case studies conducted at Romanian subsidiaries of multinational companies, we find some patterns, which could explain how the successful knowledge flows should be managed within the multinational company and outside of it, in the supply chain network.

  13. Shock tube/laser absorption studies of the decomposition of methyl formate

    KAUST Repository

    Ren, Wei; Lam, Kingyiu; Pyun, Sunghyun; Farooq, Aamir; Davidson, David Frank; Hanson, Ronald Kenneth

    2013-01-01

    Reaction rate coefficients for the major high-temperature methyl formate (MF, CH3OCHO) decomposition pathways, MF → CH3OH + CO (1), MF →CH2O+CH2O (2), and MF→ CH4 + CO2 (3), were directly measured in a shock tube using laser absorption of CO (4.6 μm), CH2O (306 nm) and CH4 (3.4 μm). Experimental conditions ranged from 1202 to 1607 K and 1.36 to 1.72 atm, with mixtures varying in initial fuel concentration from 0.1% to 3% MF diluted in argon. The decomposition rate coefficients were determined by monitoring the formation rate of each target species immediately behind the reflected shock waves and modeling the species time-histories with a detailed kinetic mechanism [12]. The three measured rate coefficients can be well-described using two-parameter Arrhenius expressions over the temperature range in the present study: k1 = 1.1 × 1013 exp(-29556/T, K) s -1, k2 = 2.6 × 1012 exp(-32052/T, K) s-1, and k3 = 4.4 × 1011 exp(-29 078/T, K) s-1, all thought to be near their high-pressure limits. Uncertainties in the k1, k2 and k3 measurements were estimated to be ±25%, ±35%, and ±40%, respectively. We believe that these are the first direct high-temperature rate measurements for MF decomposition and all are in excellent agreement with the Dooley et al. [12] mechanism. In addition, by also monitoring methanol (CH3OH) and MF concentration histories using a tunable CO2 gas laser operating at 9.67 and 9.23 μm, respectively, all the major oxygen-carrying molecules were quantitatively detected in the reaction system. An oxygen balance analysis during MF decomposition shows that the multi-wavelength laser absorption strategy used in this study was able to track more than 97% of the initial oxygen atoms in the fuel. © 2012 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

  14. Numerical study on the effects of absorptivity on performance of flat plate solar collector of a water heater

    Science.gov (United States)

    Tambunan, D. R. S.; Sibagariang, Y. P.; Ambarita, H.; Napitupulu, F. H.; Kawai, H.

    2018-03-01

    The characteristics of absorber plate of a flat plate solar collector play an important role in the improvement of the performance. In this work, a numerical analysis is carried out to explore the effect of absorptivity and emissivity of absorber plate to the performance of the solar collector of a solar water heater. For a results comparison, a simple a simple solar box cooker with absorber area of 0.835 m × 0.835 m is designed and fabricated. It is employed to heat water in a container by exposing to the solar radiation in Medan city of Indonesia. The transient governing equations are developed. The governing equations are discretized and solved using the forward time step marching technique. The results reveal that the experimental and numerical results show good agreement. The absorptivity of the plate absorber and emissivity of the glass cover strongly affect the performance of the solar collector.

  15. X-ray Absorption Fine Structure (XAFS) Studies of Oxide Glasses—A 45-Year Overview

    Science.gov (United States)

    Zanotto, Edgar Dutra

    2018-01-01

    X-ray Absorption Fine Structure (XAFS) spectroscopy has been widely used to characterize the short-range order of glassy materials since the theoretical basis was established 45 years ago. Soon after the technique became accessible, mainly due to the existence of Synchrotron laboratories, a wide range of glassy materials was characterized. Silicate glasses have been the most studied because they are easy to prepare, they have commercial value and are similar to natural glasses, but borate, germanate, phosphate, tellurite and other less frequent oxide glasses have also been studied. In this manuscript, we review reported advances in the structural characterization of oxide-based glasses using this technique. A focus is on structural characterization of transition metal ions, especially Ti, Fe, and Ni, and their role in different properties of synthetic oxide-based glasses, as well as their important function in the formation of natural glasses and magmas, and in nucleation and crystallization. We also give some examples of XAFS applications for structural characterization of glasses submitted to high pressure, glasses used to store radioactive waste and medieval glasses. This updated, comprehensive review will likely serve as a useful guide to clarify the details of the short-range structure of oxide glasses. PMID:29382102

  16. Study and selection of structured packing material: metallic, polymeric or ceramic to operate a column of absorption polluting gases coming from brick kilns efficiently

    International Nuclear Information System (INIS)

    Salazar P, A.

    2012-01-01

    materials studied, the higher density, lower modulus of elasticity, the lower corrosion resistance in the presence of 1 N H 2 SO 4 aqueous solution. The study of material properties, revealed that the metallic material is more resistant to abrasive wear, the more tenacious, more chemically resistant in the presence of Mea aqueous solution of 30% by weight, as well as the most efficient, improvement an absorption of 95% CO 2 , followed by the polymeric material, which is the most ductile, the more elastic, and its low hardness is susceptible to scratching and abrasion, its hydrophobicity, it takes longer to form the liquid film in the absorption process, improved a 93% absorption, was the most chemically resistant in the presence of 1 N H 2 SO 4 aqueous solution. The ceramic allowed 84% absorption, was the most rigid fragile, susceptible to wear and its porosity reduce the contact area between the liquid and gas, resulting be the contactor that improves minus efficiency in the absorption process. (Author)

  17. Origin of the Absorption Band of Bromophenol Blue in Acidic and Basic pH: Insight from a Combined Molecular Dynamics and TD-DFT/MM Study.

    Science.gov (United States)

    Chattopadhyaya, M; Murugan, N Arul; Rinkevicius, Zilvinas

    2016-09-15

    We study the linear and nonlinear optical properties of a well-known acid-base indicator, bromophenol blue (BPB), in aqueous solution by employing static and integrated approaches. In the static approach, optical properties have been calculated using time-dependent density functional theory (TD-DFT) on the fully relaxed geometries of the neutral and different unprotonated forms of BPB. Moreover, both closed and open forms of BPB were considered. In the integrated approach, the optical properties have been computed over many snapshots extracted from molecular dynamics simulation using a hybrid time-dependent density functional theory/molecular mechanics approach. The static approach suggests closed neutral ⇒ anionic interconversion as the dominant mechanism for the red shift in the absorption spectra of BPB due to a change from acidic to basic pH. It is found by employing an integrated approach that the two interconversions, namely open neutral ⇒ anionic and open neutral ⇒ dianionic, can contribute to the pH-dependent shift in the absorption spectra of BPB. Even though both static and integrated approaches reproduce the pH-dependent red shift in the absorption spectra of BPB, the latter one is suitable to determine both the spectra and spectral broadening. Finally, the computed static first hyperpolarizability for various protonated and deprotonated forms of BPB reveals that this molecule can be used as a nonlinear optical probe for pH sensing in addition to its highly exploited use as an optical probe.

  18. Calcium absorption

    International Nuclear Information System (INIS)

    Carlmark, B.; Reizenstein, P.; Dudley, R.A.

    1976-01-01

    The methods most commonly used to measure the absorption and retention of orally administered calcium are reviewed. Nearly all make use of calcium radioisotopes. The magnitude of calcium absorption and retention depends upon the chemical form and amount of calcium administered, and the clinical and nutritional status of the subject; these influences are briefly surveyed. (author)

  19. Spectral studies of ocean water with space-borne sensor SCIAMACHY using Differential Optical Absorption Spectroscopy (DOAS

    Directory of Open Access Journals (Sweden)

    M. Vountas

    2007-09-01

    Full Text Available Methods enabling the retrieval of oceanic parameter from the space borne instrumentation Scanning Imaging Absorption Spectrometer for Atmospheric ChartographY (SCIAMACHY using Differential Optical Absorption Spectroscopy (DOAS are presented. SCIAMACHY onboard ENVISAT measures back scattered solar radiation at a spectral resolution (0.2 to 1.5 nm. The DOAS method was used for the first time to fit modelled Vibrational Raman Scattering (VRS in liquid water and in situ measured phytoplankton absorption reference spectra to optical depths measured by SCIAMACHY. Spectral structures of VRS and phytoplankton absorption were clearly found in these optical depths. Both fitting approaches lead to consistent results. DOAS fits correlate with estimates of chlorophyll concentrations: low fit factors for VRS retrievals correspond to large chlorophyll concentrations and vice versa; large fit factors for phytoplankton absorption correspond with high chlorophyll concentrations and vice versa. From these results a simple retrieval technique taking advantage of both measurements is shown. First maps of global chlorophyll concentrations were compared to the corresponding MODIS measurements with very promising results. In addition, results from this study will be used to improve atmospheric trace gas DOAS-retrievals from visible wavelengths by including these oceanographic signatures.

  20. A single-dose, randomized, cross-over, two-way, open-label study for comparing the absorption of boswellic acids and its lecithin formulation.

    Science.gov (United States)

    Riva, Antonella; Morazzoni, Paolo; Artaria, Christian; Allegrini, Pietro; Meins, Jürgen; Savio, Daniele; Appendino, Giovanni; Schubert-Zsilavecz, Manfred; Abdel-Tawab, Mona

    2016-11-15

    The oral administration of the gum resin extracts of Indian frankincense (Boswellia serrata Roxb. ex Colebr) results in very low plasma concentrations of boswellic acids (BAs), being far below the pharmacologically active concentrations required in vitro for anti-inflammatory activity. For that reason the use of Indian frankincense in clinical practice and pharmaceutical development has substantially lagged behind. Recently the application of new formulation technologies resulted in a formulation of frankincense extract with lecithin, which revealed improved absorption and tissue penetration of BAs in a rodent study, leading for the first time to plasma concentrations of BAs in the range of their anti-inflammatory activity. In order to verify these encouraging results in humans, the absorption of a standardized Boswellia serrata extract (BE) and its lecithin formulation (CSP) was comparatively investigated in healthy volunteers. According to a randomized cross-over design with two treatments, two sequences and two periods, 12 volunteers alternatively received the lecithin-formulated Boswellia extract (CSP) or the non-formulated Boswellia extract (BE) at a dosage of 2×250mg capsules. The plasma concentrations of the six major BAs (KBA, AKBA, βBA, αBA, AβBA, AαBA) were determined using LC/MS. With the exception of KBA, a significantly higher (both in terms of weight-to-weight and molar comparison) and quicker absorption of BAs from the lecithin formulation was observed, leading to C max in the range required for the interaction with their molecular targets. These findings pave the way to further studies evaluating the clinical potential of BAs, and verify the beneficial effect of lecithin formulation to improve the absorption of poorly soluble phytochemicals. Copyright © 2016 The Authors. Published by Elsevier GmbH.. All rights reserved.

  1. Unimolecular decomposition of formic and acetic acids: A shock tube/laser absorption study

    KAUST Repository

    Elwardany, A.

    2014-07-16

    The thermal decomposition of formic acid (HCOOH) and acetic acid (CH3COOH), two carboxylic acids which play an important role in oxygenate combustion chemistry, were investigated behind reflected shock waves using laser absorption. The rate constants of the primary decomposition pathways of these acids:(HCOOH → CO + H2 O (R 1); HCOOH → CO2 + H2 (R 2); CH3 COOH → CH4 + CO2 (R 3); CH3 COOH → CH2 CO + H2 O (R 4)) were measured using simultaneous infrared laser absorption of CO, CO2 and H2O at wavelengths of 4.56, 4.18 and 2.93 microns, respectively. Reaction test conditions covered temperatures from 1230 to 1821 K and pressures from 1.0 to 6.5 atm for dilute mixtures of acids (0.25-0.6%) in argon. The rate constants of dehydration (R1) and decarboxylation (R2) reactions of formic acid were calculated by fitting exponential functions to the measured CO, CO2 and H2O time-history profiles. These two decomposition channels were found to be in the fall-off region and have a branching ratio, k1/k2, of approximately 20 over the range of pressures studied here. The best-fit Arrhenius expressions of the first-order rates of R1 and R2 were found to be:(k1 (1 atm) = 1.03 × 1011 exp (- 25651 / T) s- 1 (± 37 %); k1 (6.5 atm) = 9.12 × 1012 exp (- 30275 / T) s- 1 (± 32 %); k2 (1 atm) = 1.79 × 108 exp (- 21133 / T) s- 1 (± 41 %); k2 (6.5 atm) = 2.73 × 108 exp (- 20074 / T) s- 1 (± 37 %)). The rate constants for acetic acid decomposition were obtained by fitting simulated profiles, using an acetic acid pyrolysis mechanism, to the measured species time-histories. The branching ratio, k4/k3, was found to be approximately 2. The decarboxylation and dehydration reactions of acetic acid appear to be in the falloff region over the tested pressure range:(k3 (1 atm) = 3.18 × 1011 exp (- 28679 / T) s- 1 (± 30 %); k3 (6 atm) = 3.51 × 1012 exp (- 31330 / T) s- 1 (± 26 %); k4 (1 atm) = 7.9 × 1011 exp (- 29056 / T) s- 1 (± 34 %); k4 (6 atm) = 6.34 × 1012 exp (- 31330 / T) s

  2. A study on the inhibitory mechanism for cholesterol absorption by α-cyclodextrin administration

    Directory of Open Access Journals (Sweden)

    Takahiro Furune

    2014-12-01

    Full Text Available Background: Micelle formation of cholesterol with lecithin and bile salts is a key process for intestinal absorption of lipids. Some dietary fibers commonly used to reduce the lipid content in the body are thought to inhibit lipid absorption by binding to bile salts and decreasing the lipid solubility. Amongst these, α-cyclodextrin (α-CD is reportedly one of the most powerful dietary fibers for decreasing blood cholesterol. However, it is difficult to believe that α-CD directly removes cholesterol because it has a very low affinity for cholesterol and its mechanism of action is less well understood than those of other dietary fibers. To identify this mechanism, we investigated the interaction of α-CD with lecithin and bile salts, which are essential components for the dissolution of cholesterol in the small intestine, and the effect of α-CD on micellar solubility of cholesterol.Results: α-CD was added to Fed-State Simulated Intestinal Fluid (FeSSIF, and precipitation of a white solid was observed. Analytical data showed that the precipitate was a lecithin and α-CD complex with a molar ratio of 1:4 or 1:5. The micellar solubility of cholesterol in the mixture of FeSSIF and α-CD was investigated, and found to decrease through lecithin precipitation caused by the addition of α-CD, in a dose-dependent manner. Furthermore, each of several other water-soluble dietary fibers was added to the FeSSIF, and no precipitate was generated.Conclusion: This study suggests that α-CD decreases the micellar solubility of cholesterol in the lumen of the small intestine via the precipitation of lecithin from bile salt micelles by complex formation with α-CD. It further indicates that the lecithin precipitation effect on the bile salt micelles by α-CD addition clearly differs from addition of other water-soluble dietary fibers. The decrease in micellar cholesterol solubility in the FeSSIF was the strongest with α-CD addition.

  3. Unimolecular decomposition of formic and acetic acids: A shock tube/laser absorption study

    KAUST Repository

    Elwardany, A.; Nasir, E.F.; Es-sebbar, Et-touhami; Farooq, Aamir

    2014-01-01

    The thermal decomposition of formic acid (HCOOH) and acetic acid (CH3COOH), two carboxylic acids which play an important role in oxygenate combustion chemistry, were investigated behind reflected shock waves using laser absorption. The rate constants of the primary decomposition pathways of these acids:(HCOOH → CO + H2 O (R 1); HCOOH → CO2 + H2 (R 2); CH3 COOH → CH4 + CO2 (R 3); CH3 COOH → CH2 CO + H2 O (R 4)) were measured using simultaneous infrared laser absorption of CO, CO2 and H2O at wavelengths of 4.56, 4.18 and 2.93 microns, respectively. Reaction test conditions covered temperatures from 1230 to 1821 K and pressures from 1.0 to 6.5 atm for dilute mixtures of acids (0.25-0.6%) in argon. The rate constants of dehydration (R1) and decarboxylation (R2) reactions of formic acid were calculated by fitting exponential functions to the measured CO, CO2 and H2O time-history profiles. These two decomposition channels were found to be in the fall-off region and have a branching ratio, k1/k2, of approximately 20 over the range of pressures studied here. The best-fit Arrhenius expressions of the first-order rates of R1 and R2 were found to be:(k1 (1 atm) = 1.03 × 1011 exp (- 25651 / T) s- 1 (± 37 %); k1 (6.5 atm) = 9.12 × 1012 exp (- 30275 / T) s- 1 (± 32 %); k2 (1 atm) = 1.79 × 108 exp (- 21133 / T) s- 1 (± 41 %); k2 (6.5 atm) = 2.73 × 108 exp (- 20074 / T) s- 1 (± 37 %)). The rate constants for acetic acid decomposition were obtained by fitting simulated profiles, using an acetic acid pyrolysis mechanism, to the measured species time-histories. The branching ratio, k4/k3, was found to be approximately 2. The decarboxylation and dehydration reactions of acetic acid appear to be in the falloff region over the tested pressure range:(k3 (1 atm) = 3.18 × 1011 exp (- 28679 / T) s- 1 (± 30 %); k3 (6 atm) = 3.51 × 1012 exp (- 31330 / T) s- 1 (± 26 %); k4 (1 atm) = 7.9 × 1011 exp (- 29056 / T) s- 1 (± 34 %); k4 (6 atm) = 6.34 × 1012 exp (- 31330 / T) s

  4. A study on flexural and water absorption of surface modified rice husk flour/E-glass/polypropylene hybrid composite

    Science.gov (United States)

    Rassiah, K.; Sin, T. W.; Ismail, M. Z.

    2016-10-01

    This work is to study the effects of rice husk (RH)/E-Glass (EG)/polypropylene (PP) hybrid composites in terms of flexural and water absorption properties. The tests conducted are the flexural test and also the water absorption test using two types of water: distilled and sea water. The hybrid composites are prepared with various ratios of fibre weight fractions and the rice husk is treated using 2% Sodium Hydroxide (NaOH) to improve interaction and adhesion between the non-polar matrix and the polar lignocellulosic fibres. It was found that the content of rice husk/E-Glass fillers affected the structural integrity and flexural properties of hybrid composites. In addition, a higher ratio of rice husk contributes to higher water absorption in the hybrid composites.

  5. Absorption heat pumps

    International Nuclear Information System (INIS)

    Formigoni, C.

    1998-01-01

    A brief description of the difference between a compression and an absorption heat pump is made, and the reasons why absorption systems have spread lately are given. Studies and projects recently started in the field of absorption heat pumps, as well as criteria usually followed in project development are described. An outline (performance targets, basic components) of a project on a water/air absorption heat pump, running on natural gas or LPG, is given. The project was developed by the Robur Group as an evolution of a water absorption refrigerator operating with a water/ammonia solution, which has been on the market for a long time and recently innovated. Finally, a list of the main energy and cost advantages deriving from the use of absorption heat pumps is made [it

  6. Techniques and problems in studying intestinal absorption with radioactive isotopes in children

    International Nuclear Information System (INIS)

    James, W.P.T.; Waterlow, J.C.

    1976-01-01

    Radioactive isotopes give substantial promise for assisting the study of gastrointestinal absorption in children in that they allow reduction or elimination of the collection of blood, urine and faeces specimens. These operations are particularly difficult and unreliable in infants, on whom greatest interest in paediatric gastroenterology is centred in the tropics. Here intestinal malabsorption is most commonly associated with malnutrition, lactose intolerance, gastroenteritis, parasitic infestation and iron-deficiency anaemia. Two general techniques that have been employed are whole-body counting and analyses of 14 CO 2 exhaled in the breath after the feeding of 14 C-labelled nutrients. The former is advantageous if radionuclides suitable for the test at hand exist; the latter may be hard to interpret because of problems in the distribution and metabolism of the nutrient and intermediary products. Proper selection and understanding of the tests is particularly important in paediatric work, where the use of radioactive tracer techniques is unacceptable merely for the convenience of the investigator. (author)

  7. Experimental studies of methemoglobinemia due to percutaneous absorption of sodium nitrite.

    Science.gov (United States)

    Saito, T; Takeichi, S; Nakajima, Y; Yukawa, N; Osawa, M

    1997-01-01

    Methemoglobin formation caused by a liniment solution containing sodium nitrite (30 g/L and 140 g/L) was studied in rats with normal or abraded skin, by measuring the methemoglobin concentration before and after application of liniment solutions with differing nitrite concentration. Each liniment solution (120 microL) was applied. Methemoglobin was measured for 180 minutes using a hemoximeter. Simultaneously, arterial blood pressure and cutaneous blood flow was measured by laser Doppler flowmetry and a pressure transducer. After the application of each liniment solution to normal skin, the methemoglobin concentration was not significantly modified depending on the time after application. Application of liniment solution to abraded skin (140 g/L) resulted in a marked increase in methemoglobin concentration. A remarkable decrease in arterial blood pressure and subcutaneous blood flow were observed after application of liniment solution to abraded skin (140 g/L). Each of these findings are characteristic of nitrite and they imply the percutaneous absorption of nitrite. Regardless of the nitrite concentration, the methemoglobin concentration was consistently higher in abraded skin than in normal skin.

  8. Fluorescence and absorption spectroscopy for warm dense matter studies and ICF plasma diagnostics

    Science.gov (United States)

    Hansen, Stephanie

    2017-10-01

    The burning core of an inertial confinement fusion (ICF) plasma at stagnation is surrounded by a shell of warm, dense matter whose properties are difficult both to model (due to a complex interplay of thermal, degeneracy, and strong coupling effects) and to diagnose (due to low emissivity and high opacity). We demonstrate a promising technique to study the warm dense shells of ICF plasmas based on the fluorescence emission of dopants or impurities in the shell material. This emission, which is driven by x-rays produced in the hot core, exhibits signature changes in response to compression and heating. High-resolution measurements of absorption and fluorescence features can refine our understanding of the electronic structure of material under high compression, improve our models of density-driven phenomena such as ionization potential depression and plasma polarization shifts, and help diagnose shell density, temperature, mass distribution, and residual motion in ICF plasmas at stagnation. Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA-0003525. This work was supported by the U.S. Department of Energy, Office of Science Early Career Research Program, Office of Fusion Energy Sciences under FWP-14-017426.

  9. Electronic structure of titania aerogels: Soft x-ray absorption study

    International Nuclear Information System (INIS)

    Kucheyev, S.O.; Van Buuren, T.V.; Baumann, T.F.; Satcher, J.H.; Willey, T.M.; Muelenberg, R.W.; Felter, T.E.; Poco, J.E.; Gammon, S.A.; Terminello, L.J.

    2004-01-01

    Full text: Titania aerogels - a somewhat extreme form of nanoporous TiO 2 - are open-cell solid foams derived from highly crosslinked gels by drying them under supercritical conditions. In this presentation, the unoccupied electronic states of TiO 2 aerogels are studied by soft x-ray absorption near-edge structure (XANES) spectroscopy. High-resolution O K-edge and Ti L 2,3 -edge XANES spectra of aerogels are compared with those of rutile, anatase, and unrelaxed amorphous phases of full- density TiO 2 . Results show that all the main spectroscopic features of aerogels, reflecting the element-specific partial density of empty electronic states and correlation effects, can be attributed to the absence of long-range order in stoichiometric amorphous TiO 2 . Based on these results, we discuss the effects of short- and long-range order on the electronic structure of TiO 2 . This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under Contract No. W-7405-Eng-48

  10. Iron in Alzheimer's and Control Hippocampi - Moessbauer, Atomic Absorption and ELISA Studies

    International Nuclear Information System (INIS)

    Galazka-Friedman, J.; Szlachta, K.; Bauminger, E.R.; Koziorowski, D.; Friedman, A.; Tomasiuk, R.; Jaklewicz, A.; Wszolek, Z.K.; Dickson, D.; Kaplinska, K.

    2011-01-01

    Alzheimer disease is a neurodegenerative process of unknown mechanism taking place in a part of the brain - hippocampus. Oxidative stress and the role of iron in it is one of the suggested mechanisms of cells death. In this study several methods were used to assess iron and iron binding compounds in human hippocampus tissues. Moessbauer spectroscopy was used for identification of the iron binding compound and determination of total iron concentration in 12 control and one Alzheimer disease sample of hippocampus. Moessbauer parameters obtained for all samples suggest that most of the iron is ferritin-like iron. The average concentration of iron determined by Moessbauer spectroscopy in control hippocampus was 45 ± 10 ng/mg wet tissue. The average concentration of iron in 10 Alzheimer disease samples determined by atomic absorption was 66 ± 13 ng/mg wet tissue. The concentration of H and L chains of ferritin in 20 control and 10 AD hippocampi was assessed with enzyme-linked immuno-absorbent assay. The concentration of H and L ferritin was higher in Alzheimer disease compared to control (19.36 ± 1.51 vs. 5.84 ± 0.55 ng/μg protein for H, and 1.39 ± 0.25 vs. 0.55 ± 0.10 for L). This 3-fold increase of the concentration of ferritin is accompanied by a small increase of the total iron concentration. (authors)

  11. Shapes of the $^{192,190}$Pb ground states from beta decay studies using the total absorption technique

    CERN Document Server

    Estevez Aguado, M.E.; Agramunt, J.; Rubio, B.; Tain, J.L.; Jordan, D.; Fraile, L.M.; Gelletly, W.; Frank, A.; Csatlos, M.; Csige, L.; Dombradi, Zs.; Krasznahorkay, A.; Nacher, E.; Sarriguren, P.; Borge, M.J.G.; Briz, J.A.; Tengblad, O.; Molina, F.; Moreno, O.; Kowalska, M.; Fedosseev, V.N.; Marsh, B.A.; Fedorov, D.V.; Molkanov, P.L.; Andreyev, A.N.; Seliverstov, M.D.; Burkard, K.; Huller, W.

    2015-01-01

    The beta decay of $^{192,190}$Pb has been studied using the total absorption technique at the ISOLDE(CERN) facility. The beta-decay strength deduced from the measurements, combined with QRPA theoretical calculations, allow us to infer that the ground states of the $^{192,190}$Pb isotopes are spherical. These results represent the first application of the shape determination method using the total absorption technique for heavy nuclei and in a region where there is considerable interest in nuclear shapes and shape effects.

  12. Effects of xylitol on carbohydrate digesting enzymes activity, intestinal glucose absorption and muscle glucose uptake: a multi-mode study.

    Science.gov (United States)

    Chukwuma, Chika Ifeanyi; Islam, Md Shahidul

    2015-03-01

    The present study investigated the possible mechanism(s) behind the effects of xylitol on carbohydrate digesting enzymes activity, muscle glucose uptake and intestinal glucose absorption using in vitro, ex vivo and in vivo experimental models. The effects of increasing concentrations of xylitol (2.5%-40% or 164.31 mM-2628.99 mM) on alpha amylase and alpha glucosidase activity in vitro and intestinal glucose absorption and muscle glucose uptake were investigated under ex vivo conditions. Additionally, the effects of an oral bolus dose of xylitol (1 g per kg BW) on gastric emptying and intestinal glucose absorption and digesta transit in the different segments of the intestinal tract were investigated in normal and type 2 diabetic rats at 1 hour after dose administration, when phenol red was used as a recovery marker. Xylitol exhibited concentration-dependent inhibition of alpha amylase (IC₅₀ = 1364.04 mM) and alpha glucosidase (IC₅₀ = 1127.52 mM) activity in vitro and small intestinal glucose absorption under ex vivo condition. Xylitol also increased dose dependent muscle glucose uptake with and without insulin, although the uptake was not significantly affected by the addition of insulin. Oral single bolus dose of xylitol significantly delayed gastric emptying, inhibited intestinal glucose absorption but increased the intestinal digesta transit rate in both normal and diabetic rats compared to their respective controls. The data of this study suggest that xylitol reduces intestinal glucose absorption via inhibiting major carbohydrate digesting enzymes, slowing gastric emptying and fastening the intestinal transit rate, but increases muscle glucose uptake in normal and type 2 diabetic rats.

  13. Bimetallic Catalysts and Platinum Surfaces Studied by X-ray Absorption Spectroscopy and Scanning Tunnelling Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Roenning, Magnus

    2000-07-01

    Bimetallic catalyst systems used in Fischer-Tropsch synthesis (Co-Re/Al{sub 2}O{sub 3}) and in the naphtha reforming process (Pt-Re/Al{sub 2}O{sub 3}) have been studied in situ using X-ray absorption spectroscopy (EXAFS). Additionally, the adsorption of ethene on platinum single crystal surfaces has been investigated using scanning tunnelling microscopy. In situ EXAFS at the cobalt K absorption edge have been carried out at 450{sup o}C on the hydrogen reduction of a rhenium-promoted Co{sub 3}O{sub 4}/Al{sub 2}O{sub 3} catalyst. Reductions carried out using 100% hydrogen and 5% hydrogen in helium gave different results. Whereas the reduction using dilute hydrogen leads to bulk-like metallic cobalt particles (hcp or fcc), reaction with pure hydrogen yields a more dispersed system with smaller cobalt metal particles (< 40 A). The results are rationalised in terms of different degrees of reoxidation of cobalt by the higher and lower concentrations of water generated during the reduction of cobalt oxide by 100% and 5% hydrogen, respectively. Additionally, in both reduction protocols a small fraction (3 -4 wt%) of the cobalt content is randomly dispersed over the tetrahedral vacancies of the alumina support. This dispersion occurs during reduction and not calcination. The cobalt in these sites cannot be reduced at 450 {sup o}C. The local environments about the rhenium atoms in Co-Re/{gamma}-A1{sub 2}O{sub 3} catalyst after different reduction periods have been studied by X-ray absorption spectroscopy. A bimetallic catalyst containing 4.6 wt% cobalt and 2 wt% rhenium has been compared with a corresponding monometallic sample with 2 wt% rhenium on the same support. The rhenium L{sub III} EXAFS analysis shows that bimetallic particles are formed after reduction at 450{sup o}C with the average particle size being 10-15 A. Rhenium is shown to be reduced at a later stage than cobalt. The fraction of cobalt atoms entering the support obstructs the access to the support for the

  14. X-ray absorption near edge structure (XANES) study of some hydroxamic mixed ligand copper complexes

    International Nuclear Information System (INIS)

    Mishra, A; Parsai, N; Shrivastava, B D; Soni, N

    2012-01-01

    With the advent of modern bright synchrotron radiation sources, X-ray absorption spectra has emerged as a powerful technique for local structure determination, which can be applied to any type of material. The X-ray absorption measurements of four hydroxamic mixed ligand copper complexes have been performed at the recently developed BL-8 Dispersive EXAFS beamline at 2.5 GeV Indus-2 synchrotron at RRCAT, Indore, India. The X-ray absorption near edge structure (XANES) data obtained has been processed using data analysis program Athena. The energies of the K absorption edge, chemical shifts, edge-widths, shifts of the principal absorption maximum in the complexes have been determined. The values of the chemical shift suggest that copper is in oxidation state +2 in all of the complexes. The chemical shift data has been utilized to estimate effective nuclear charge on copper atom. The order of the chemical shifts has been correlated to the relative ionic character of the bonding in these complexes.

  15. Time-resolved study of a pulsed dc discharge using quantum cascade laser absorption spectroscopy : NO and gas temperature kinetics

    NARCIS (Netherlands)

    Welzel, S.; Gatilova, L.; Röpcke, J.; Rousseau, A.

    2007-01-01

    In a pulsed dc discharge of an Ar–N2 mixture containing 0.91% of NO the kinetics of the destruction of NO has been studied under static and flowing conditions, i.e. in a closed and open discharge tube (p = 266 Pa). For this purpose quantum cascade laser absorption spectroscopy (QCLAS) in the

  16. NO kinetics in pulsed low-pressure nitrogen plasmas studied by time resolved quantum cascade laser absorption spectroscopy

    NARCIS (Netherlands)

    Welzel, S.; Guaitella, O.; Lazzaroni, C.; Pintassilgo, C.; Rousseau, A.; Röpcke, J.

    2011-01-01

    Time-resolved quantum cascade laser absorption spectroscopy at 1897 cm-1 (5.27 µm) has been applied to study the NO(X) kinetics on the micro- and millisecond time scale in pulsed low-pressure N2/NO dc discharges. Experiments have been performed under flowing and static gas conditions to infer the

  17. Phase transition in LiVO2 studied by near-edge x-ray-absorption spectroscopy

    NARCIS (Netherlands)

    Pen, HF; Tjeng, LH; Pellegrin, E; deGroot, FMF; Sawatzky, GA; vanVeenendaal, MA; Chen, CT

    1997-01-01

    We present temperature-dependent V-2p and O-1s x-ray-absorption spectra of LiVO2. The aim of this study is to monitor changes in electronic structure on going through the phase transition. The spectral changes turn out to be very small: the V-3d-O-2p hybridization does not change considerably, and

  18. Experimental and theoretical study of electronic structure of aluminum in extreme conditions with X-ray absorption spectroscopy

    International Nuclear Information System (INIS)

    Festa, Floriane

    2013-01-01

    Matter in extreme conditions belongs to Warm Dense Matter regime which lays between dense plasma regime and condensed matter. This regime is still not well known, indeed it is very complex to generate such plasma in the laboratory to get experimental data and validate models. The goal of this thesis is to study electronic structure of aluminum in extreme conditions with X-ray absorption spectroscopy. Experimentally aluminum has reached high densities and high temperatures, up to now unexplored. An X-ray source has also been generated to probe highly compressed aluminum. Two spectrometers have recorded aluminum absorption spectra and aluminum density and temperature conditions have been deduced thanks to optical diagnostics. Experimental spectra have been compared to ab initio spectra, calculated in the same conditions. The theoretical goal was to validate the calculation method in high densities and high temperatures regime with the study of K-edge absorption modifications. We also used absorption spectra to study the metal-non metal transition which takes place at low density (density ≤ solid density). This transition could be study with electronic structure modifications of the system. (author) [fr

  19. A simulation study on the abatement of CO2 emissions by de-absorption with monoethanolamine.

    Science.gov (United States)

    Greer, T; Bedelbayev, A; Igreja, J M; Gomes, J F; Lie, B

    2010-01-01

    Because of the adverse effect of CO2 from fossil fuel combustion on the earth's ecosystems, the most cost-effective method for CO2 capture is an important area of research. The predominant process for CO2 capture currently employed by industry is chemical absorption in amine solutions. A dynamic model for the de-absorption process was developed with monoethanolamine (MEA) solution. Henry's law was used for modelling the vapour phase equilibrium of the CO2, and fugacity ratios calculated by the Peng-Robinson equation of state (EOS) were used for H2O, MEA, N2 and O2. Chemical reactions between CO2 and MEA were included in the model along with the enhancement factor for chemical absorption. Liquid and vapour energy balances were developed to calculate the liquid and vapour temperature, respectively.

  20. Regional disparities, absorption capacity and Structural Fund payments: A case study of the Czech Republic

    Directory of Open Access Journals (Sweden)

    Novosák Jiří

    2017-12-01

    Full Text Available The intention of this paper is to provide empirical evidence on how the factors of socio-economic disadvantage and absorption capacity influence the spatial distribution of Structural Fund (SF payments among the Czech Republic’s micro-regions during the 2007–2013 programming period. The empirical results indicate that agglomeration economies, innovation and entrepreneurship are associated with higher SF absorption capacity and higher SF payments, challenging the tendency for socio-economically disadvantaged regions to converge. SF absorption capacity measured especially by the number of project applications submitted for SF financing and by the average SF budget per project application, is a crucial concept in order to understand the relationship between within-country regional disparities and SF interventions.

  1. Study on absorption, accumulation and distribution of 90Sr in yellow-feather broiler

    International Nuclear Information System (INIS)

    Shang Zhaorong; Xu Shiming; Zhao Wenhu; Hou Lanxin

    1993-04-01

    The feeding experiment was carried out for yellow-feather broiler with 90 Sr(NO 3 ) 2 having activities of 1.85 x 10 0 ∼ 1.85 x 10 4 Bq/chicken to observe the regular pattern of absorption and distribution of 90 Sr in its organs and tissues. The results are as follows: The absorption rate of 90 Sr by oral feeding is very low. The most of 90 Sr is drained away by daily excreta from the body. The half-time of its feeding is within 24 hours. The accumulated dose varies with the time and different feeding methods. The more 90 Sr is fed, the more 90 Sr is absorbed, however, the uptake rate of 90 Sr is decreasing. The distribution of 90 Sr for bone is very strong and the partition ratio is about 90%. The absorption coefficient of 90 Sr in organs and tissues of broiler is presented

  2. Study on Coloration Mechanism of Chinese Ancient Ceramics by X-ray Absorption Near-edge Structure

    Science.gov (United States)

    Peng, Y. H.; Xie, Z.; He, J. F.; Liu, Q. H.; Pan, Z. Y.; Cheng, W. R.; Wei, S. Q.

    2013-04-01

    The Fe K-edge X-ray absorption near-edge structure (XANES) spectra of a series of ceramic shards were measured by fluorescence mode to reveal the color-generating techniques of Chinese porcelain. The analysis disclosed relationships among the chemical form of the iron, the firing conditions and the colors of the ceramics. The results indicate that the coloration for different ceramics depend on the valence states of iron as the main color element in glaze and the proportion of Fe2+ and Fe3+ was attributed to the baking technology. The findings provide important information for archaeologist on the coloration researches.

  3. An experimental study of water absorption characteristics for generator stator winding insulation

    International Nuclear Information System (INIS)

    Lee, D. S.; Bae, Y. C.; Kim, H. S.; Kim, Y. H.; Lee, H.

    2004-01-01

    Leaking water coolant into stator electrical insulation is a growing concern for the aging water-cooled generator since leaks in the generator water-cooled stator winding can affect machine availability and insulation life. But a domestic techniques of such field are insufficient and depend wholly on GE or TOSHIBA technique. Therefore this paper introduces measuring principle and developed measuring system, which has been used to detecting wet absorption. We accomplished the experiment with a stator promotion of virtue which is used in actual power plant. Also, experimental method of generator stator winding, which is investigated into wet absorption test

  4. A high resolution x-ray fluorescence spectrometer for near edge absorption studies

    International Nuclear Information System (INIS)

    Stojanoff, V.; Hamalainen, K.; Siddons, D.P.; Hastings, J.B.; Berman, L.E.; Cramer, S.; Smith, G.

    1991-01-01

    A high resolution fluorescence spectrometer using a Johann geometry in a back scattering arrangement was developed. The spectrometer, with a resolution of 0.3 eV at 6.5 keV, combined with an incident beam, with a resolution of 0.7 eV, form the basis of a high resolution instrument for measuring x-ray absorption spectra. The advantages of the instrument are illustrated with the near edge absorption spectrum of dysprosium nitrate. 10 refs., 4 figs

  5. Excited-State Dynamics of Carotenoids Studied by Femtosecond Transient Absorption Spectroscopy

    International Nuclear Information System (INIS)

    Lee, Ingu; Pang, Yoonsoo; Lee, Sebok

    2014-01-01

    Carotenoids, natural antenna pigments in photosynthesis share a symmetric backbone of conjugated polyenes. Contrary to the symmetric and almost planar geometries of carotenoids, excited state structure and dynamics of carotenoids are exceedingly complex. In this paper, recent infrared and visible transient absorption measurements and excitation dependent dynamics of 8'-apo-β-caroten-8'-al and 7',7'-dicyano-7'-apo-β-carotene will be reviewed. The recent visible transient absorption measurements of 8'-apo-β-caroten-8'-al in polar and nonpolar solvents will also be introduced to emphasize the complex excited-state dynamics and unsolved problems in the S 2 and S 1 excited states

  6. Chemical vapor generation of silver for atomic absorption spectrometry with the multiatomizer: Radiotracer efficiency study and characterization of silver species

    Energy Technology Data Exchange (ETDEWEB)

    Musil, Stanislav [Institute of Analytical Chemistry of the ASCR, v.v.i., Videnska 1083, 142 20 Prague 4 (Czech Republic); Charles University in Prague, Faculty of Science, Dept. of Analytical Chemistry, Albertov 8, 128 43 Prague 2 (Czech Republic); Kratzer, Jan; Vobecky, Miloslav [Institute of Analytical Chemistry of the ASCR, v.v.i., Videnska 1083, 142 20 Prague 4 (Czech Republic); Hovorka, Jan [Charles University in Prague, Faculty of Science, Institute for Environmental Studies, Benatska 2, 128 01 Prague 2 (Czech Republic); Benada, Oldrich [Institute of Microbiology of the ASCR, v.v.i., Videnska 1083, 142 20 Prague 4 (Czech Republic); Matousek, Tomas, E-mail: matousek@biomed.cas.c [Institute of Analytical Chemistry of the ASCR, v.v.i., Videnska 1083, 142 20 Prague 4 (Czech Republic)

    2009-11-15

    Volatile Ag species were generated in flow injection arrangement from nitric acid environment in the presence of surfactants (Triton X-100 and Antifoam B) and permanent Pd deposits as the reaction modifiers. Atomic absorption spectrometry (AAS) with multiple microflame quartz tube atomizer heated to 900 deg. C was used for atomization; evidence was found for thermal mechanism of atomization. Relative and absolute limits of detection (3sigma, 250 mul sample loop) measured under optimized conditions were: 1.4 mug l{sup -1} and 0.35 ng, respectively. The efficiency of chemical vapor generation (CVG) as well as spatial distribution of residual analyte in the apparatus was studied by {sup 111}Ag radioactive indicator (half-life 7.45 days) of high specific activity. It was found out that 23% of analyte was released into the gaseous phase. However, only 8% was found on filters placed at the entrance to the atomizer due to transport losses. About 40% of analyte remained in waste liquid, whereas the rest was found deposited over the CVG system. Presented study follows the hypothesis that the 'volatile' Ag species are actually metallic nanoparticles formed upon reduction in liquid phase and then released with good efficiency to the gaseous phase. Number/charge size distributions of dry aerosol were determined by Scanning Mobility Particle Sizer. Ag was detected in 40-45 nm particles holding 10 times more charge if compared to Boltzmann equilibrium. At the same time, Ag was also present on 150 nm particles, the main size mode of the CVG generator. The increase of Ag in standards was reflected by proportional increase in particle number/charge for 40-45 nm size particles only. Transmission electron microscopy revealed particles of 8 +- 2 nm sampled from the gaseous phase, which were associated in isolated clusters of few to few tens of nanometres. Ag presence in those particles was confirmed by Energy Dispersive X-ray Spectroscopy (EDS) analysis.

  7. Mathematics Teachers' Views of Accountability Testing Revealed through Lesson Study

    Science.gov (United States)

    Yarema, Connie H.

    2010-01-01

    The practice of lesson study, a professional development model originating in Japan, aligns well with recommendations from research for teacher professional development. Lesson study is also an inductive research method that uncovers student thinking and, in parallel, grants teacher-educators the opportunity to study teachers' thinking about…

  8. Analysis of Intra- and Intersubject Variability in Oral Drug Absorption in Human Bioequivalence Studies of 113 Generic Products.

    Science.gov (United States)

    Sugihara, Masahisa; Takeuchi, Susumu; Sugita, Masaru; Higaki, Kazutaka; Kataoka, Makoto; Yamashita, Shinji

    2015-12-07

    In this study, the data of 113 human bioequivalence (BE) studies of immediate release (IR) formulations of 74 active pharmaceutical ingredients (APIs) conducted at Sawai Pharmaceutical Co., Ltd., was analyzed to understand the factors affecting intra- and intersubject variabilities in oral drug absorption. The ANOVA CV (%) calculated from area under the time-concentration curve (AUC) in each BE study was used as an index of intrasubject variability (Vintra), and the relative standard deviation (%) in AUC was used as that of intersubject variability (Vinter). Although no significant correlation was observed between Vintra and Vinter of all drugs, Vintra of class 3 drugs was found to increase in association with a decrease in drug permeability (P(eff)). Since the absorption of class 3 drugs was rate-limited by the permeability, it was suggested that, for such drugs, the low P(eff) might be a risk factor to cause a large intrasubject variability. To consider the impact of poor water solubility on the variability in BE study, a parameter of P(eff)/Do (Do; dose number) was defined to discriminate the solubility-limited and dissolution-rate-limited absorption of class 2 drugs. It was found that the class 2 drugs with a solubility-limited absorption (P(eff)/Do high intrasubject variability. Furthermore, as a reason for high intra- or intersubject variability in AUC for class 1 drugs, effects of drug metabolizing enzymes were investigated. It was demonstrated that intrasubject variability was high for drugs metabolized by CYP3A4 while intersubject variability was high for drugs metabolized by CYP2D6. For CYP3A4 substrate drugs, the Km value showed the significant relation with Vintra, indicating that the affinity to the enzyme can be a parameter to predict the risk of high intrasubject variability. In conclusion, by analyzing the in house data of human BE study, low permeability, solubility-limited absorption, and high affinity to CYP3A4 are identified as risk factors for

  9. A feasibility study on oxidation state of arsenic in cut tobacco, mainstream cigarette smoke and cigarette ash by X-ray absorption spectroscopy

    International Nuclear Information System (INIS)

    Liu, C.; Hu, J.; McAdam, K.G.

    2009-01-01

    This work describes the application of synchrotron-based X-ray Absorption Near-Edge Structure spectroscopy to study the oxidation state of arsenic in cigarette mainstream smoke, cut tobacco and cigarette ash. The level of arsenic in the total particulate matter of the smoke is approximately 1 ppm for the standard research reference cigarette 2R4F and its replacement 3R4F. Smoke particulate samples collected by a conventional glass-fiber membrane (commercially known as Cambridge filter pad) and a jet-impaction method were analyzed and compared. In addition smoke particulate samples were aged either at ambient temperature or at 195 K. X-ray Absorption Near-Edge Structure spectroscopy results revealed that the cut tobacco powder and cigarette ash contained almost exclusively As V . The smoke particulate samples however contained a mixture of As III and As V . The As V in the smoke particulate was reduced to As III upon aging. Stabilizing the smoke particulate matter at 195 K by solid CO 2 slowed down this aging reaction and revealed a higher percentage of As V . This behavior is consistent with the redox properties of the arsenic species and the smoke particulate matrix.

  10. Nutrition and magnesium absorption

    NARCIS (Netherlands)

    Brink, E.J.

    1992-01-01

    The influence of various nutrients present in dairy products and soybean-based products on absorption of magnesium has been investigated. The studies demonstrate that soybean protein versus casein lowers apparent magnesium absorption in rats through its phytate component. However, true

  11. Experimental Studies of the Mechanism of Photon Absorption on Light Nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Morrow, Steven A. [Univ. of Edinburgh, Scotland (United Kingdom)

    2000-09-13

    A measurement of the reaction 12C(γ,pγ') has been made with tagged photons in the range 49.47 < E γ < 70.24 MeV. The relative population of a triplet of states, (7/2-, 1/2+, 5/2+) at Eex ≅ 7 MeV in the residual nucleus 11B, following the reaction 12C(γ,p), has been made by directly resolving their de-excitation γ-ray decay to the ground state of 11B. This measurement constitutes the highest resolution ever achieved in determining the excitation function of the residual nucleus after a (γ,p) reaction (~ 48 keV FWHM at Eex ≅ 7 MeV). Comparison has been made with the data of Kuzin et al, who also measured the relative populations with a resolution of ~ 270 keV at Eex ≅ 7 MeV. The 7/2- state at 6.74 MeV has been observed to be the most strongly excited state of the triplet in agreement with Kuzin et al. Disagreement has been found for the relative strengths of the 1/2+ and 5/2+ states in the triplet. An estimation of the maximum effect of angular correlations between the ejected proton and de-excitation γ-ray has been included in the analysis. This effect increases the disagreement between the measurements. A study of the reaction 12C(e,e'p) has been made in the missing momentum region 260 < pm < 320 MeV/c. A Rosenbluth separation of the reaction cross section has been carried out in parallel kinematics to measure the structure functions WL and WT. The experimental data have been compared with Complete Distorted Wave Impulse Approximation calculations and Random Phase Approximation calculations. The latter when including virtual photon absorption on 2-body currents (Meson Exchange Currents + Isobar Currents) are seen to describe the reduced cross sections better than 1-body current or Complete Distorted Wave Impulse Approximation calculations. For the

  12. Study Reveals Brain Biology behind Self-Control

    Science.gov (United States)

    Sparks, Sarah D.

    2011-01-01

    A new neuroscience twist on a classic psychology study offers some clues to what makes one student able to buckle down for hours of homework before a test while his classmates party. The study published in the September 2011 edition of "Proceedings of the National Academy of Science," suggests environmental cues may "hijack" the brain's mechanisms…

  13. Study of absorption spectra for alkali and alkaline earth metal salts in flameless atomic absorption spectrometry using a carbon tube atomizer

    International Nuclear Information System (INIS)

    Yasuda, Seiji; Kakiyama, Hitoo

    1975-01-01

    Absorption spectra of various salts such as alkali metal salts, alkaline earth dichlorides, and ammonium halides were investigated and absorptions of some molecular species produced in the carbon tube were identified. The aqueous solution (20 μl) containing 1.0 mg/ml of each salt was placed in the carbon tube atomizer and heated in a similar manner to usual flameless atomic absorption method. D 2 -lamp was used as a continuous light source and argon gas was employed as an inert sheath gas. The spectra were obtained over the range of wavelength 200 to 350 nm. When alkali halides were feeded, the absorption spectra agreed with those of alkali halide vapors. Therefore, in such cases vapors of the alkali halides were probably produced by the sublimation or vaporization in the atomizer. The spectra of alkali perchlorates were considered to be those of alkali chlorides produced by the pyrolysis of the perchlorates in the atomizer. The absorptions of alkaline earth chlorides below 250 nm were probably due to their gaseous states. Sulfur dioxide was found to be produced by the pyrolysis of alkali sulfates, bisulfates and sulfites in the atomizer, Alkali phosphates and pyrophosphates gave almost identical spectra below 300 nm. Gamma band spectrum of nitrogen monoxide was observed from 200 to 240 nm during ashing at bout 330 0 C for alkali nitrates and nitrites. Ammonia vapor was produced from ammonium halides during drying at about 170 0 C. Although the absorptions of alkali carbonates and hydroxides were almost undetectable, the same spectra as those of alkali halides were observed by the addition of ammonium halides to the solutions of alkali compounds. This shows that alkali halides are produced in the atomizer by the addition of halide ions. (auth.)

  14. A study of the energy absorption and exposure buildup factors of some anti-inflammatory drugs

    International Nuclear Information System (INIS)

    Ekinci, Neslihan; Kavaz, Esra; Özdemir, Yüksel

    2014-01-01

    Human radiation exposure is increasing due to radiation development in science and technology. The development of radioprotective agents is important for protecting patients from the side effects of radiotherapy and for protecting the public from unwanted irradiation. Radioprotective agents are used to reduce the damage caused by radiation in healthy tissues. There are several classes of radioprotective compounds that are under investigation. Analgesics and anti-inflammatory compounds are being considered for treating or preventing the effects of damage due to radiation exposure, or for increasing the chance of survival after exposure to a high dose of radiation. In this study, we investigated the radioprotective effects of some analgesic and anti-inflammatory compounds by evaluating buildup factors. The gamma ray energy absorption (EABF) and exposure buildup factors (EBF) were calculated to select compounds in a 0.015–15 MeV energy region up to a penetration depth of 40 mfp (mean free path). Variations of EABF and EBF with incident photon energy and penetration depth elements were also investigated. Significant variations in both EABF and EBF values were observed for several compounds at the moderate energy region. At energies below 0.15 MeV, EABF and EBF values increased with decreasing equivalent atomic number (Z eq ) of the samples. In addition, EABF and EBF were the largest for ibuprofen, aspirin, paracetamol, naproxen and ketoprofen at 0.05 and 0.06 MeV, respectively, and the EABF value was 0.1 MeV for aceclofenac. From these results, we concluded that the buildup of photons is less for aceclofenac compared to other materials. - Highlights: • Buildup factors of anti-inflammatory drugs have been calculated by a G-P fitting method. • Z eff of diclofenac was observed higher than other compounds. • It was found that buildup of photons is less for aceclofenac and diclofenac. • It would be appealing to use aceclofenac and diclofenac as radioprotective

  15. Feasibility Study of Multi-Wavelength Differential Absorption LIDAR for CO2 Monitoring

    Directory of Open Access Journals (Sweden)

    Chengzhi Xiang

    2016-06-01

    Full Text Available To obtain a better understanding of carbon cycle and accurate climate prediction models, highly accurate and temporal resolution observation of atmospheric CO2 is necessary. Differential absorption LIDAR (DIAL remote sensing is a promising technology to detect atmospheric CO2. However, the traditional DIAL system is the dual-wavelength DIAL (DW-DIAL, which has strict requirements for wavelength accuracy and stability. Moreover, for on-line and off-line wavelengths, the system’s optical efficiency and the change of atmospheric parameters are assumed to be the same in the DW-DIAL system. This assumption inevitably produces measurement errors, especially under rapid aerosol changes. In this study, a multi-wavelength DIAL (MW-DIAL is proposed to map atmospheric CO2 concentration. The MW-DIAL conducts inversion with one on-line and multiple off-line wavelengths. Multiple concentrations of CO2 are then obtained through difference processing between the single on-line and each of the off-line wavelengths. In addition, the least square method is adopted to optimize inversion results. Consequently, the inversion concentration of CO2 in the MW-DIAL system is found to be the weighted average of the multiple concentrations. Simulation analysis and laboratory experiments were conducted to evaluate the inversion precision of MW-DIAL. For comparison, traditional DW-DIAL simulations were also conducted. Simulation analysis demonstrated that, given the drifting wavelengths of the laser, the detection accuracy of CO2 when using MW-DIAL is higher than that when using DW-DIAL, especially when the drift is large. A laboratory experiment was also performed to verify the simulation analysis.

  16. Optical absorption and magnetic circular dichroism spectra of thiouracils: a quantum mechanical study in solution

    DEFF Research Database (Denmark)

    Martínez-Fernández, L.; Fahleson, Tobias; Norman, Patrick

    2017-01-01

    The excited electronic states of 2-thiouracil, 4-thiouracil and 2,4-dithiouracil, the analogues of uracil where the carbonyl oxygens are substituted by sulphur atoms, have been investigated by computing the magnetic circular dichroism (MCD) and one-photon absorption (OPA) spectra at the time-depe...

  17. Optical absorption and electron spin resonance studies of Cu 2 in ...

    Indian Academy of Sciences (India)

    B2O3–As2O3 glasses. N Srinivasa Rao Shashidhar ... K Siva Kumar Syed Rahman. Ceramics and Glasses Volume 28 Issue 6 October 2005 pp 589-592 ... Keywords. Glass transition temperature; ESR; optical absorption; bonding parameters.

  18. Absorption of magnesium in intestinal loop studied by the multitracer technique

    International Nuclear Information System (INIS)

    Yoshida, Shozo; Yamasaki, Mineo; Morikawa, Hajime

    2004-01-01

    We investigated Mg absorption in the intestine, and pregnancy-associated changes in Mg absorption by the rat everted gut sac method. Heavy ion beam accelerated by ring-cyclotron was irradiated to a titanium target and the radioactive multitracer solution which includes 28 Mg was made. 9 weeks old female Wistar rats (non-pregnancy, 6∼20th day of the pregnancy) were fasted overnight and anesthetized. Four segments of the intestine were isolated and everted to prepare sac specimens with mucosa outside. Each specimen was filled with multitracer solution and was immersed in the same solution. After incubation the multitracer solutions in both of inside and outside the sacs were removed. The radioactivity of the each sample was determined by gamma-ray spectrometry. In non-pregnant state, the active transport of Mg from mucosal side into serosal side exists only in colon. This active transport of Mg in colon during pregnancy was significantly decreased than in non-pregnant state. The mechanism and importance of the decrease in Mg absorption during pregnancy are still unclear. In humans, the intracellular and extracellular Mg concentrations decrease with the normal pregnancy course, especially in preeclampsia. The association between the changes in active Mg absorption during pregnancy and the pathogenesis should be clarified as early as possible. (author)

  19. Quantum theory and experimental studies of absorption spectra and photoisomerization of azobenzene polymers

    DEFF Research Database (Denmark)

    Pedersen, Thomas Garm; Ramanujam, P.S.; Johansen, P.M.

    1998-01-01

    The microscopic properties of azobenzene chromophores are important for a correct description of optical storage systems based on photoinduced anisotropy in azobenzene polymers. A quantum model of these properties is presented and verified by comparison to experimental absorption spectra for trans...

  20. 5 K extended X-ray absorption fine structure and 40 K 10-s resolved extended X-ray absorption fine structure studies of photolyzed carboxymyoglobin

    International Nuclear Information System (INIS)

    Teng, T.Y.; Huang, H.W.; Olah, G.A.

    1987-01-01

    A previous extended X-ray absorption fine structure (EXAFS) study of photolyzed carboxymyoglobin (MbCO) has provoked much discussion on the heme structure of the photoproduct (Mb*CO). The EXAFS interpretation that the Fe-Co distance increases by no more than 0.05 A following photodissociation has been regarded as inconsistent with optical, infrared, and magnetic susceptibility studies. The present experiment was performed with well-characterized dry film samples in which MbCO molecules were embedded in a poly(vinyl alcohol) matrix. The sample had a high protein concentration (12 mM) to yield adequate EXAFS signals but was very thin (40 μm) so that complete photolysis could be easily achieved by a single flash from a xenon lamp. Although the electronic state of Mb*CO resembles that of deoxymyoglobin (deoxy-Mb), direct comparison of EXAFS spectra indicates that structurally Mb*CO is much closer to MbCO than to deoxy-Mb. Our EXAFS analysis shows that photolysis of MbCO at 5 K leads to a stable intermediate state in which CO has moved away from iron by a distance of 0.27-0.45 A, but the 5-coordinate heme structure is strained in a form similar to that of MbCO; the resolution of the CO position depends on the structure parameters of MbCO which we use as a reference for the analysis of Mb*CO. At 40 K, from 1 to 10 s after photolysis, 42% of the photoproduct has relaxed to the ground state, and the EXAFS spectrum of the remaining photoproduct is indistinguishable from that of the 5 K photoproduct

  1. The cytotoxic effect of palytoxin on Caco-2 cells hinders their use for in vitro absorption studies.

    Science.gov (United States)

    Pelin, M; Sosa, S; Della Loggia, R; Poli, M; Tubaro, A; Decorti, G; Florio, C

    2012-02-01

    Palytoxin (PLTX), found in Palythoa zoanthids and Ostreopsis dinoflagellates, has also been detected in crabs and fish, through which it can enter into the food chain. Indeed, PLTX is considered the causative agent of several cases of human seafood poisoning resulting in systemic symptoms. Available epidemiological data on PLTX human toxicity suggest that the intestinal tract may be one of its in vivo targets and its potential site of access into the bloodstream. Hence, the purpose of this study was to investigate the suitability of the human intestinal Caco-2 cell line for evaluating PLTX oral absorption. A detailed analysis of PLTX cytotoxicity revealed a high sensitivity of Caco-2 cells: 4h toxin exposure reduced mitochondrial activity (MTT assay, EC(50) of 8.9±3.7×10(-12)M), cell density (SRB assay, EC(50) of 2.0±0.6×10(-11)M) and membrane integrity (LDH release, EC(50) of 4.5±1.4×10(-9)M and PI uptake, EC(50) of 1.0±0.8×10(-8)M). After low PLTX concentration (1.0×10(-11)M) exposure for 1-8h, followed by 24h recovery time in toxin-free medium, cell density reduction was only partially reversible. These results indicate that, due to the high susceptibility to PLTX cytotoxic effects, Caco-2 cells do not represent an appropriate and reliable model for investigating intestinal barrier permeation by this toxin. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. A trade-off study revealing nested timescales of constraint

    NARCIS (Netherlands)

    Wijnants, M.L.; Cox, R.F.A; Hasselman, F.; Bosman, A. M. T.; Van Orden, G.

    2012-01-01

    This study investigates human performance in a cyclic Fitts task at three different scales of observation, either in the presence (difficult condition) or in the absence (easy condition) of a speed–accuracy trade-off. At the fastest scale, the harmonicity of the back and forth movements, which

  3. In vitro study revealed different size behavior of different nanoparticles

    International Nuclear Information System (INIS)

    Schaudien, Dirk; Knebel, Jan; Creutzenberg, Otto

    2012-01-01

    Toxicity of nanoparticles is depending not only on the size of the primary particles but on the size of their agglomerates. Therefore, further studies are needed to examine the behavior of nanoparticles after they have gotten in contact with cells. The presented study investigated the change of size of different commercially available nanoparticles after applying them to different cell lines such as A549, Calu-3, 16HBE14o and LK004 representative for the different parts of the human lung. The different nanoparticles exhibited differences in behavior of size. TiO 2 P25 showed a tendency to increase, whereas TiO 2 T805 and Printex ® 90 remained more or less at the same size. In contrast, ZnO < 50 nm particles showed a significant decrease of size.

  4. Study of the pattern of iron absorption and utilization in anaemias associated with malnutrition

    International Nuclear Information System (INIS)

    Ahmed, K.

    1976-06-01

    The objective of this investigation was to observe in poor populations, generally malnourished and anemic, the effect on hemoglobin level and percentage iron absorption of (1) an improved diet and (2) vitamin C supplementation alone. Percentage iron absorption was measured, after consumption of a meal into which 3-5 μCi 59 Fe as ferrous sulphate had been homogeneously mixed, by whole-body counting and also by measuring the concentration of the isotope in the blood at about two weeks. As subjects of the investigation were used adult males and females, from poor local population groups, who had no hookworm or other problems causing bleeding. A total of 236 subjects, subsequent to a preliminary screening and performance of appropriate laboratory tests, were placed on an improved diet containing about 300 g/d protein in the form of fish, meat, and pulses, plus leafy vegetables. It could not be assured, however, that all continued to take this diet during most of the 90-180 d test period during which they lived at home. Measurements were made of hemoglobin level and percentage absorption of iron from a test meal, before and after the test period of improved nutrition. In females the hemoglobin level (g/100 ml blood) rose from 10.2+-0.5 to 12.4+-0.4, and in males from 9.8+-0.4 to 12.3+-0.5, where errors quoted are standard errors of the mean. In females the percentage iron absorption rose from 18.8%+-1.8% to 24.5%+-2.5%, and in males from 14.4%+-1.6% to 19.2%+-2.2%. All the increases were judged to be statistically significant. Another group of 220 subjects, after preliminary screening, were told to take vitamin C supplements of 100 mg/d with their two principal meals over a period of 90-120 days. Hemoglobin levels, but not iron absorption from a test meal containing no supplement of vitamin C, was found to be statistically significantly improved at the end of the test period. This confirms the potential of vitamin C as a supplement for improving absorption of dietary

  5. Despite some concerns, impact study reveals support for nuke

    International Nuclear Information System (INIS)

    Anon.

    1978-01-01

    A survey of 37 Hartsville, Tennessee community leaders indicates the community supports construction of a nuclear generating plant and does not see any major environmental impacts. The leaders do anticipate growth-related disruptions during the construction phase. The ERDA-sponsored social impact study is being conducted by the Oak Ridge National Laboratory to serve as a guide in planning future energy projects and for comparison with a coal-fired project under development in Georgia. Statistics from the survey are summarized. General observations note that the leaders tend to overestimate opposition to the nuclear plant and that local concerns focus on housing and traffic problems. The Tennessee Valley Authority is supplying funds for a mitigation plan, which is generally well received by the community

  6. Study and Optimization of Helicopter Subfloor Energy Absorption Structure with Foldcore Sandwich Structures

    Science.gov (United States)

    HuaZhi, Zhou; ZhiJin, Wang

    2017-11-01

    The intersection element is an important part of the helicopter subfloor structure. In order to improve the crashworthiness properties, the floor and the skin of the intersection element are replaced with foldcore sandwich structures. Foldcore is a kind of high-energy absorption structure. Compared with original structure, the new intersection element shows better buffering capacity and energy-absorption capacity. To reduce structure’s mass while maintaining the crashworthiness requirements satisfied, optimization of the intersection element geometric parameters is conducted. An optimization method using NSGA-II and Anisotropic Kriging is used. A significant CPU time saving can be obtained by replacing numerical model with Anisotropic Kriging surrogate model. The operation allows 17.15% reduce of the intersection element mass.

  7. Population specific absorption studies for some diet incorporated trace elements : comparison with ICRP data

    International Nuclear Information System (INIS)

    Parameswaran, M.; Dang, H.S.

    1999-01-01

    Daily intake and excretion can provide an important information regarding the absorption through the gastro-intestinal tract (f1 factor) of trace elements incorporated in diet. The absorption may depend upon the kind of diet consumed, the content of the fibre, protein etc and it could be quite different for two populations groups with entirely different food habits. ICRP has provided data on the intake and excretion of 63 trace elements by Caucasian population representing North American and European adults. This paper reports intake and excretion of twelve elements Na, K, Ca, Mg, Cu, Mn, Rb, Fe, Zn, Sr, Li and Cr for an urban adult Indian population group and compares with corresponding data on ICRP reference man. (author)

  8. A model for absorption determination of radioactive materials: application in the radio dosimetry and nutrition study

    International Nuclear Information System (INIS)

    Mesquita, C.H. de.

    1991-01-01

    A three-parameter model of the sigmoidal relationship is proposed to explain the food passage by intestinal tube. These parameters are: U = intestinal non-absorbed radioactivity; d parameter related to intestinal food dispersion; and t 50 = time to maximal appearance of material from the intestinal lumen. In order to illustrate the applications of this model and its validity, the absorption of 65 Zn from casein semi-purified diet was evaluated in rats. There was a good agreement between the predicted values and the experimental data when the sigmoidal component was added to the conventional multicompartimental equations. With this kind of model the time to maximal appearance (hours), the true absorption level, the fecal concentration and the intestinal dispersion of the ingested radioactivity material may be determined. (author)

  9. Excited-State Dynamics of Carotenoids Studied by Femtosecond Transient Absorption Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ingu; Pang, Yoonsoo [Department of Physics and Photon Science, Gwangju (Korea, Republic of); Lee, Sebok [Gwangju Institute of Science and Technology, Gwangju (Korea, Republic of)

    2014-03-15

    Carotenoids, natural antenna pigments in photosynthesis share a symmetric backbone of conjugated polyenes. Contrary to the symmetric and almost planar geometries of carotenoids, excited state structure and dynamics of carotenoids are exceedingly complex. In this paper, recent infrared and visible transient absorption measurements and excitation dependent dynamics of 8'-apo-β-caroten-8'-al and 7',7'-dicyano-7'-apo-β-carotene will be reviewed. The recent visible transient absorption measurements of 8'-apo-β-caroten-8'-al in polar and nonpolar solvents will also be introduced to emphasize the complex excited-state dynamics and unsolved problems in the S{sub 2} and S{sub 1} excited states.

  10. Two-photon spectroscopy study of edge absorption peculiarities in oxygen-octahedric ferroelectrics

    International Nuclear Information System (INIS)

    Shablaev, S.I.; Danishevskij, A.M.; Subashiev, V.K.

    1984-01-01

    Two-photon absorption (TPA) spectra of ferroelectric crystals with BaTiO 3 , KTaO 3 and SrTiO 3 perovskite strUcture Were obtained. The detailed investigation of temperature dependence of edge spectrum regions was conducted and on the basis of their analysis the indirect character of edge absorption was concluded for all mentioned crystals. TPA spectra of BaTiO 3 and KTaO 3 are characterized by the regions corresponding to one indirect edge TPA spectra of SrTiO 3 - to two indirect edges. The corresponding inter-zone gaps were determined for all investigated crystals, the energy of phonons, participating in indirect two photon transitions, inter-zone gaps, corresponding to direct transitions were determined as well

  11. A systematic neutron reflectometry study on hydrogen absorption in thin Mg{sub 1-x}Al{sub x} alloy films

    Energy Technology Data Exchange (ETDEWEB)

    Fritzsche, H.; Poirier, E. [National Research Council of Canada, Chalk River, ON (Canada). Canadian Neutron Beam Centre; Haagsma, J.; Ophus, C.; Luber, E.; Harrower, C.T.; Mitlin, D. [Alberta Univ., Edmonton, AB (Canada). Dept. of Chemical and Materials Engineering; National Research Council of Canada, Edmonton, AB (Canada). National Inst. for Nanotechnology

    2010-10-15

    Various methods for storing hydrogen have been examined in an effort to find ways to store hydrogen in increasingly smaller volumes with decreasing weight of the whole hydrogen storage system. Metal hydrides, in which hydrogen is chemically bound to a metal atom, are considered to be very promising candidates for hydrogen storage because they have high gravimetric and volumetric storage capacities. This study investigated the effect of different magnesium (Mg) and aluminium (Al) ratios on the absorption and desorption properties of thin films. Neutron reflectometry (NR) was used in this study to better understand the absorption and desorption properties of commercially promising hydrogen storage materials. The large negative scattering length of hydrogen atoms changes the reflectivity curve substantially, so that NR can determine the total amount of stored hydrogen as well as the hydrogen distribution along the film normal, with nanometer resolution. In order to use NR, the samples must have smooth surfaces, and the film thickness should range between 10 and 200 nm. Thin Mg{sub 1-x}Al{sub x} alloy films (x = 0.2, 0.3, 0.4, 0.67) capped with a palladium (Pd) catalyst layer were used in this study. The NR experiments revealed that Mg{sub 0.7}Al{sub 0.3} is the optimum composition for this binary alloy system, with the highest amount of stored hydrogen and the lowest desorption temperature. All the thin films expanded by approximately 20 percent due to hydrogen absorption. The hydrogen was stored only in the MgAl layer without any hydrogen in the Pd layer. It was concluded that NR can be used to effectively determine the hydrogen profile in thin MgAl films. 29 refs., 5 figs.

  12. Nationwide Genomic Study in Denmark Reveals Remarkable Population Homogeneity.

    Science.gov (United States)

    Athanasiadis, Georgios; Cheng, Jade Y; Vilhjálmsson, Bjarni J; Jørgensen, Frank G; Als, Thomas D; Le Hellard, Stephanie; Espeseth, Thomas; Sullivan, Patrick F; Hultman, Christina M; Kjærgaard, Peter C; Schierup, Mikkel H; Mailund, Thomas

    2016-10-01

    Denmark has played a substantial role in the history of Northern Europe. Through a nationwide scientific outreach initiative, we collected genetic and anthropometrical data from ∼800 high school students and used them to elucidate the genetic makeup of the Danish population, as well as to assess polygenic predictions of phenotypic traits in adolescents. We observed remarkable homogeneity across different geographic regions, although we could still detect weak signals of genetic structure reflecting the history of the country. Denmark presented genomic affinity with primarily neighboring countries with overall resemblance of decreasing weight from Britain, Sweden, Norway, Germany, and France. A Polish admixture signal was detected in Zealand and Funen, and our date estimates coincided with historical evidence of Wend settlements in the south of Denmark. We also observed considerably diverse demographic histories among Scandinavian countries, with Denmark having the smallest current effective population size compared to Norway and Sweden. Finally, we found that polygenic prediction of self-reported adolescent height in the population was remarkably accurate (R 2 = 0.639 ± 0.015). The high homogeneity of the Danish population could render population structure a lesser concern for the upcoming large-scale gene-mapping studies in the country. Copyright © 2016 by the Genetics Society of America.

  13. X-ray Absorption Study of Graphene Oxide and Transition Metal Oxide Nanocomposites

    OpenAIRE

    Gandhiraman, Ram P.; Nordlund, Dennis; Javier, Cristina; Koehne, Jessica E.; Chen, Bin; Meyyappan, M.

    2014-01-01

    The surface properties of the electrode materials play a crucial role in determining the performance and efficiency of energy storage devices. Graphene oxide and nanostructures of 3d transition metal oxides were synthesized for construction of electrodes in supercapacitors, and the electronic structure and oxidation states were probed using near-edge X-ray absorption fine structure. Understanding the chemistry of graphene oxide would provide valuable insight into its reactivity and properties...

  14. Procedure for intercomparison study for trace elements determination in soil samples by absorption spectroscopy

    International Nuclear Information System (INIS)

    Sanchez P, L.A.; Benavides M, A.M.

    1996-01-01

    In the environmental sampling analysis there is very important to establish an adequate methodologies on the laboratories for improvement the quality of the results obtained, so the establishment of a qualified laboratories network for environmental analysis. The objective of this work is to show the working plan for the analysis of eight elements on a Russian soil sample for an interlaboratory comparison with IAEA, by the Absorption spectroscopy technique using flame. (Author)

  15. Studies of hydrogen incorporation in hydrogenated amorphous carbon films by infrared absorption spectroscopy

    International Nuclear Information System (INIS)

    Alameh, R.; Bounouh, Y.; Sadki, A.; Naud, C.; Theye, M.L.

    1997-01-01

    Author.Hydrogenated amorphous carbon (a-C:H) films presently attract considerable interest because of their potential applications in the domain of multifunctional coatings: transparent in the infrared, very hard, chemically inert, etc...This material is rather complex since it contains C atoms in both sp 3 (diamond) and sp 2 (graphite) electronic configurations, as well as a large concentration of H atoms. Its properties are strongly dependent on the deposition conditions which determine the film microstructure, i.e. the relative proportions of sp 3 and sp 2 C sites, their connection in the network and the hydrogen bonding modes. It has been suggested that the sp 2 C sites tend to cluster into unsaturated chains ans rings, which are then embedded in the sp 3 C sites m atrix . Hydrogen incorporation plays a crucial role in this intrinsic microheterogeneity, which determines the electronic properties, and especially the gap value, of a-C:H. We here present and discuss the results of Fourrier transform infrared absorption spectroscopy measurements performed on a-C:H films prepared under different conditions and submitted to controlled annealing cycles, which exhibit quite different optical gap values (from 1 to 2.5 eV). We carefully analyze the absorption bands detected in the 400-7500 cm -1 spectral range in terms of the vibration modes of C-H and C-C bonds in different local environments and we interpret the results in relation with the film microstructure and optical properties. Special attention is also paid to the absorption background and to the variations of the whole absorption spectra with measurement temperature

  16. Study on aroma components of osmanthus by absorption wire gas chromatography/mass spectrometry

    International Nuclear Information System (INIS)

    Feng Janyue; Zhao Jing; Huang Qiaoqiao; Feng Lianmei

    2001-01-01

    The aroma components of fresh osmanthus are captured by absorption wires. The fragrant components absorbed in the wires are desorbed immediately at 358 degree C in Curie-point pyrolyzed, and then led into GC/MS to analyze. As a result, 41 aroma compounds such as β-linalool, linalooloxide, β-ocimene etc. in osmanthus are detected qualitatively by gas chromatography/mass spectrometry. This method can be used to analyze the change of aroma compounds of fresh flowers while blossoming

  17. Time-resolved infrared absorption study of nine TiO{sub 2} photocatalysts

    Energy Technology Data Exchange (ETDEWEB)

    Yamakata, Akira; Ishibashi, Taka-aki [Kanagawa Academy of Science and Technology (KAST), KSP, Takatsu, Kawasaki 213-0012 (Japan); Onishi, Hiroshi [Kanagawa Academy of Science and Technology (KAST), KSP, Takatsu, Kawasaki 213-0012 (Japan)], E-mail: oni@kobe-u.ac.jp

    2007-10-15

    Electron kinetics of nine TiO{sub 2} catalysts were compared in a microsecond time domain. Each catalyst was band-gap excited with an UV light pulse, and electron-induced absorption of mid infrared light was observed as a function of time delay. The probability of electron-hole recombination in the bulk, electron attachment to adsorbed oxygen, and hole attachment to adsorbed methoxy species was estimated.

  18. Time-resolved infrared absorption study of nine TiO2 photocatalysts

    International Nuclear Information System (INIS)

    Yamakata, Akira; Ishibashi, Taka-aki; Onishi, Hiroshi

    2007-01-01

    Electron kinetics of nine TiO 2 catalysts were compared in a microsecond time domain. Each catalyst was band-gap excited with an UV light pulse, and electron-induced absorption of mid infrared light was observed as a function of time delay. The probability of electron-hole recombination in the bulk, electron attachment to adsorbed oxygen, and hole attachment to adsorbed methoxy species was estimated

  19. A mechanistic understanding of ageing revealed by studying the young.

    Science.gov (United States)

    Crespi, Erica J

    2012-03-01

    A main focus within biomedical research is to understand how adverse environmental conditions experienced during early development affects lifelong health (Barker 1992). Within this context, extensive research in rodent models and humans has shown that intrauterine growth retardation (IUGR) caused by nutrient restriction during early development is often followed by post-natal 'catch-up' growth when access to food resources improves. However, this accelerated growth rate seems to come at a cost, as metabolic and endocrine processes that are programmed during this time cause later-life onset of diseases such as obesity, insulin resistance and cardiovascular disease (reviewed in Crespi & Denver 2005). In this issue Molecular Ecology, Geiger et al. (2012) asked what are the costs of catch-up growth in nutrient-restricted king penguin chicks (Fig. 1) by measuring lengths of telomeres, the protective DNA sequences at the end of chromosomes, before and after catch-up growth, as the amount and rate of telomere sequence loss over time has been associated with reduced lifespan in both model and nonmodel organisms (see reviews of Costantini et al. 2010; Haussmann & Marchetto 2010). Geiger et al. (2011) found that chicks entering the post-winter growth season at a smaller size exhibited increased growth rates (i.e. catch-up growth) at the cost of increased oxidative stress and reduced telomere lengths compared with the chicks entering the growth period at a larger size. Furthermore, chicks that did not survive had drastically shorter telomere lengths and reduced antioxidant capacities at the beginning of the growth period than all other chicks, thereby directly associating telomere length to mortality. These results suggest that while catch-up growth allows smaller chicks to head off into the world on equal footing with chicks that hatched at a larger size, it likely comes at the cost of a shortened lifespan. Thus, this study provides a mechanism that supports the

  20. A liquid-He cryostat for structural and thermal disorder studies by X-ray absorption.

    Science.gov (United States)

    Bouamrane, F; Ribbens, M; Fonda, E; Adjouri, C; Traverse, A

    2003-07-01

    A new device operating from 4.2 to 300 K is now installed on the hard X-ray station of the DCI ring in LURE in order to measure absorption coefficients. This liquid-He bath device has three optical windows. One allows the incident beam to impinge on the sample, one located at 180 degrees with respect to the sample allows transmitted beams to be detected, and another located at 90 degrees is used to detect emitted photons. Total electron yield detection mode is also possible thanks to a specific sample holder equipped with an electrode that collects the charges created by the emitted electrons in the He gas brought from the He bath around the sample. The performance of the cryostat is described by measurements of the absorption coefficients versus the temperature for Cu and Co foils. For comparison, the absorption coefficient is also measured for Cu clusters. As expected from dimension effects, the Debye temperature obtained for the clusters is lower than that of bulk Cu.

  1. On the limitations of statistical absorption studies with the Sloan Digital Sky Surveys I-III

    Science.gov (United States)

    Lan, Ting-Wen; Ménard, Brice; Baron, Dalya; Johnson, Sean; Poznanski, Dovi; Prochaska, J. Xavier; O'Meara, John M.

    2018-04-01

    We investigate the limitations of statistical absorption measurements with the SDSS optical spectroscopic surveys. We show that changes in the data reduction strategy throughout different data releases have led to a better accuracy at long wavelengths, in particular for sky line subtraction, but a degradation at short wavelengths with the emergence of systematic spectral features with an amplitude of about one percent. We show that these features originate from inaccuracy in the fitting of modeled F-star spectra used for flux calibration. The best-fit models for those stars are found to systematically over-estimate the strength of metal lines and under-estimate that of Lithium. We also identify the existence of artifacts due to masking and interpolation procedures at the wavelengths of the hydrogen Balmer series leading to the existence of artificial Balmer α absorption in all SDSS optical spectra. All these effects occur in the rest-frame of the standard stars and therefore present Galactic longitude variations due to the rotation of the Galaxy. We demonstrate that the detection of certain weak absorption lines reported in the literature are solely due to calibration effects. Finally, we discuss new strategies to mitigate these issues.

  2. Optical absorption, {sup 31}P NMR, and photoluminescence spectroscopy study of copper and tin co-doped barium–phosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Jiménez, J.A., E-mail: jose.jimenez@unf.edu; Zhao, C.

    2014-10-15

    The optical and structural properties of 50P{sub 2}O{sub 5}:50BaO glasses prepared by melting have been investigated for additive concentrations of 10 and 1 mol% of CuO and SnO dopants. Absorption and photoluminescence spectroscopies were employed in the optical characterization, whereas structural properties were assessed by {sup 31}P nuclear magnetic resonance (NMR) spectroscopy. Residual Cu{sup 2+} was detectable by absorption spectroscopy for the highest concentration of CuO and SnO. More prominently, the optical data suggests contributions from both twofold-coordinated Sn centers and Cu{sup +} ions to light absorption and emission in the glasses. The luminescence depends strongly on excitation wavelength for the highest concentration of dopants where a blue–white emission is observed under short-wavelength excitation (e.g., 260 nm) largely due to tin, while an orange luminescence is exhibited for longer excitation wavelengths (e.g., 360 nm) essentially due to Cu{sup +} ions. On the other hand, dissimilar luminescent properties were observed in connection to Cu{sup +} ions for the lowest concentration studied, as the copper ions were preferentially excited in a narrower range at shorter wavelengths near tin centers absorption. The structural analyses revealed the glass matrix to be composed essentially of Q{sup 2} (two bridging oxygens) and Q{sup 1} (one bridging oxygen) phosphate tetrahedra. A slight increase in the Q{sup 1}/Q{sup 2} ratio reflected upon SnO doping alone suggests a major incorporation of tin into the glass network via P–O–Sn bonds, compatible with the 2-coordinated state attributed to the luminescent Sn centers. However, a significant increase in the Q{sup 1}/Q{sup 2} ratio was indicated with the incorporation of copper at the highest concentration, consistent with a key role of the metal ions as network modifiers. Thus, the change in Cu{sup +} optical properties concurs with different distributions of local environments around the

  3. Multitracer study on absorption of radionuclides in atmosphere-plant system

    International Nuclear Information System (INIS)

    Ambe, Shizuko; Shinonaga, Taeko; Watanabe, Tadakazu; Yamaguchi, Isamu

    1996-01-01

    Direct absorption of atmospheric radionuclides by soybean plants was studied using a radioactive multitracer consisting of radionuclides of Sc, Mn, Co, As, Se, Rb, Sr, Y, Eu, Gd, Yb, Hf, Re, and Ir. Soybean seedlings were cultivated at 23degC in a box where multitracer-adsorbed cellulose powders were floating in air. After 28-49 day-cultivation, the plants were harvested and divided into beans (seeds and pods), leaves, stems (inside and outside), and roots. Beans or leaves originating from the same node were collected together. After washing with dilute HCl solution and distilled water, they were dried and then subjected to γ-ray measurement. It was estimated that about 0.2 % of the multitracer was absorbed by the soybean plant, of which 80 % was found in the leaves, and 10 % each in beans and stems. The relative amounts of elements in the beans, leaves, and stems markedly differed depending on the element. Among the elements, Se * was greatly accumulated in the beans, leaves, and stems. Cobalt * , Se * , and Rb * were dominant in the beans, especially in the edible part of seeds. Relative amounts of Mn * , As * , Sr * , and Re * in the seeds were very small. It is noticeable that these nuclides were found in the seeds, though they were not physically exposed to the multitracer-adsorbed cellulose powders during growth. The radioactivities of Sc * , Mn * , Co * , As * , Se * , Rb * , Sr * , Y * , Eu * , Gd * , Yb * , Hf * , Re * , and Ir * were observed for the leaves. Brown leaves accumulated greater amounts of radionuclides than green ones. Main nuclides found in the stem were Sc * , Co * , Se * , Y * , Eu * , Gd * , Yb * , Hf * , and Ir * , a larger part of them on the outside. Trace amounts of Co * , Se * , and Rb * were detected in the roots. Little leakage of the multitracer into the soil was observed. These results indicate that various radionuclides in the atmosphere were directly absorbed through soybean leaves and then transported to the edible part

  4. Study of non-validity of mixture rule near K-absorption edges by X-ray spectrometric technique

    International Nuclear Information System (INIS)

    Sharanabasappa; Chitralekha, A.; Kerur, B.R.; Anilkumar, S.

    2012-01-01

    X-ray spectrometric technique has been described to determine the X-ray mass attenuation coefficient, μ/ρ, of X-rays employing HPGe X-ray detector and radioactive sources. The photon intensity is measured by gating the channel of the spectrometer at FWHM/photo peak. Using the technique the 'best value' values of μ/ρ were obtained for those thicknesses which lie in the transmission (T) range 0.5 ≥ T ≥ 0.02. Total attenuation cross sections for other elements and lead compounds were measured at photon energies from 17 to 88 keV to study the Bragg's additivity law near the absorption edge of the lead. The measured values of mass attenuation coefficient values are compared with theoretical values obtained using Winxcom (programme). This study suggests that measured mass attenuation coefficient values at and near absorption edges differ from the theoretical value by about 17-23%. (author)

  5. Laser induced transient absorptions of the excited triplet state of 9,10-anthraquinone-2-sulfonate. A further study by 248 nm laser photolysis

    International Nuclear Information System (INIS)

    Ma Jianhua; Lin Weizheng; Wang Wenfen; Yao Side; Lin Nianyun

    1999-01-01

    Transient absorption spectrum of triplet state of 9,10-anthraquinone-2-sulfonate (AQS) in aqueous solution has been investigated using 248 nm (KrF) laser photolysis. A whole transient absorption spectrum with absorption maxim at 380 nm and 580 nm has been assigned to triple AQS from detailed kinetic analysis of decay of 380 nm and 580 nm signals, which is the neat characteristic absorption of triplet AQS reported for the first time. In addition, the difference in feature of the spectrum of triplet AQS in H 2 O and that in CH 3 CN was eliminated by further study using 248 nm laser pulses

  6. X-Ray Absorption Studies of Vanadium-Containing Metal Oxide Nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Hohn, Keith, L.

    2006-01-09

    Metal oxide nanocrystals offer significant potential for use as catalysts or catalyst supports due to their high surface areas and unique chemical properties that result from the high number of exposed corners and edges. However, little is known about the catalytic activity of these materials, especially as oxidation catalysts. This research focused on the preparation, characterization and use of vanadium-containing nanocrystals as selective oxidation catalysts. Three vanadium-containing nanocrystals were prepared using a modified sol-gel procedure: V/MgO, V/SiO2, and vanadium phosphate (VPO). These represent active oxidation catalysts for a number of industrially relevant reactions. The catalysts were characterized by x-ray diffraction and Raman, UV-VIS, infrared and x-ray absorption spectroscopies with the goal of determining the primary structural and chemical differences between nanocrystals and microcrystals. The catalytic activity of these catalysts was also studied in oxidative dehydrogenation of butane and methanol oxidation to formaldehyde. V/MgO nanocrystals were investigated for activity in oxidative dehydrogenation of butane and compared to conventional V/MgO catalysts. Characterization of V/MgO catalysts using Raman spectroscopy and x-ray absorption spectroscopy showed that both types of catalysts contained magnesium orthovanadate at vanadium loadings below 15 weight%, but above that loading, magnesium pyrovanadate may have been present. In general, MgO nanocrystals had roughly half the crystal size and double the surface area of the conventional MgO. In oxidative dehydrogenation of butane, nanocrystalline V/MgO gave higher selectivity to butene than conventional V/MgO at the same conversion. This difference was attributed to differences in vanadium domain size resulting from the higher surface areas of the nanocrystalline support, since characterization suggested that similar vanadium phases were present on both types of catalysts. Experiments in

  7. High-pressure Raman and optical absorption studies on lead pyroniobate (Pb2Nb2O7) and pressure-induced phase transitions

    International Nuclear Information System (INIS)

    Jayaraman, A.; Kourouklis, G.A.; Cooper, A.S.; Espinosa, G.P.

    1990-01-01

    High-pressure Raman scattering and optical absorption studies have been carried out on lead pyroniobate (Pb 2 Nb 2 O 7 ) up to 33 GPa, using a gasketed diamond anvil cell. The Raman study reveals the occurrence of two, possibly three, pressure-induced phase changes; a rather subtle change is indicated near 4.5 GPa. The transition near 13 GPa is attributed to a structural transition from the rhombohedral to the cubic pyrochlore structure. The third phase change occurs near 20 GPa. From the broad Raman feature that is observed at about 800 cm -1 , it is concluded that the system turns amorphous at pressures above 20 GPa. The amorphous phase recrystallizes to the original rhombohedral phase, on release of pressure. The broad Raman peaks of the recrystallized phase indicate a high degree of disorder in the material. Lead pyroniobate turns deep red near 30 GPa, from light yellow at ambient pressure. Semi quantitative absorption measurements show that the energy gap shifts red at a rate of 30 meV/GPa. This shift is attributed to the downward motion of the 5d (es) conduction band of Pb

  8. Narrative absorption

    DEFF Research Database (Denmark)

    Narrative Absorption brings together research from the social sciences and Humanities to solve a number of mysteries: Most of us will have had those moments, of being totally absorbed in a book, a movie, or computer game. Typically we do not have any idea about how we ended up in such a state. No...

  9. Studies on the absorption of iron after oral administration in piglets

    International Nuclear Information System (INIS)

    Thoren-Tolling, K.

    1975-01-01

    72 newborn piglets from 9 litters were used to determinate the retention and distribution in the body of labelled iron given either orally as ferrous fumarate (100 mg Fe 2+ ) or iron dextran (200 mg Fe 3+ ), or by injection as iron dextran (100 mg Fe 3+ ). About 25-30 % of the radioiron from a single oral dose of labelled ferrous fumarate (100 mg Fe 2+ ), and about 55-60 % from a single oral dose of labelled iron dextran (200 mg Fe 3+ ) were absorbed by the body. As iron is excreted throughout the experiment, only about 20% and 40-50% respectively of the radio-iron from these iron compounds were recovered 3 weeks after treatment. The total amounts of labelled iron retained in the body after oral administration of the same doses of these iron compounds, alone or in combination, were compared. A slight retardation of the absorption of ferrous iron was observed when iron dextran was administered simultaneeously. The absorption of iron dextran was not influenced by the simultaneous administration of ferrous fumarate. The importance of the liver as the main iron storage site was shown, and the rapid utilization of iron from storage sites, about 2-3 weeks after treatment was demonstrated. The concentration of labelled iron in urine and some lymphglands was measured. Only minute quantities of radio-iron were excreted in the urine throughout the entire experiment. The lymph nodes seem to act as iron stones after administration of iron dextran. The importance of the lymphatic tissue in absorption and storage of labelled iron is discussed. (author)

  10. Interaction between Bisphosphonates and Mineral Water: Study of Oral Risedronate Absorption in Rats.

    Science.gov (United States)

    Itoh, Akihisa; Akagi, Yuuki; Shimomura, Hitoshi; Aoyama, Takao

    2016-01-01

    Bisphosphonates are antiosteoporotic agents prescribed for patients with osteoporosis. Drug package inserts for bisphosphonate supplements indicate that their bioavailability is reduced by high levels of metal cations (Ca(2+), Mg(2+), etc.). However, standards for these cations in water used for taking risedronate have not been defined. Here, we examined the effect of calcium and magnesium in mineral waters on the bioavailability of the third-generation bisphosphonate, risedronate, following oral administration in rats. As risedronate is unchanged and eliminated renally, risedronate absorption was estimated from the amount excreted in the urine. Risedronate was dissolved in mineral water samples and administered orally at 0.35 mg/kg. Urine samples were collected for 24 h after dosing. Risedronate was extracted from urine using ion-pair solid-phase cartridges and quantified by HPLC with UV detection (262 nm). Cumulative recovery of risedronate was calculated from the amount excreted in the urine. The 24-h recovery of risedronate from evian® (0.32±0.02% [mean±standard deviation (S.D.)], n=4) and Contrex(®) (0.22±0.05%) mineral waters was significantly lower than that from tap water (0.47±0.04%, pAbsorption of risedronate in calcium chloride and magnesium chloride aqueous solutions of the same hardness (822 mg/L) was 54% (0.27±0.04%) and 12% (0.51±0.08%) lower, respectively, compared with ultrapure water; suggesting that absorption of risedronate declines as the calcium concentration of mineral waters increases. Consumption of mineral waters containing high levels of calcium (80 mg/L or above), such as evian® and Contrex(®), is therefore not recommended when taking risedronate.

  11. An immortal cell line to study the role of endogenous CFTR in electrolyte absorption.

    Science.gov (United States)

    Bell, C L; Quinton, P M

    1995-01-01

    The intact human reabsorptive sweat duct (RD) has been a reliable model for investigations of the functional role of "endogenous" CFTR (cystic fibrosis transmembrane conductance regulator) in normal and abnormal electrolyte absorptive function. But to overcome the limitations imposed by the use of fresh, intact tissue, we transformed cultured RD cells using the chimeric virus Ad5/SV40 1613 ori-. The resultant cell line, RD2(NL), has remained differentiated forming a polarized epithelium that expressed two fundamental components of absorption, a cAMP activated Cl- conductance (GCl) and an amiloride-sensitive Na+ conductance (GNa). In the unstimulated state, there was a low level of transport activity; however, addition of forskolin (10(-5) M) significantly increased the Cl- diffusion potential (Vt) generated by a luminally directed Cl- gradient from -15.3 +/- 0.7 mV to -23.9 +/- 1.1 mV, n = 39; and decreased the transepithelial resistance (Rt) from 814.8 +/- 56.3 omega.cm2 to 750.5 +/- 47.5 omega.cm2, n = 39, (n = number of cultures). cAMP activation, anion selectivity (Cl- > I- > gluconate), and a dependence upon metabolic energy (metabolic poisoning inhibited GCl), all indicate that the GCl expressed in RD2(NL) is in fact CFTR-GCl. The presence of an apical amiloride-sensitive GNa was shown by the amiloride (10(-5) M) inhibition of GNa as indicated by a reduction of Vt and equivalent short circuit current by 78.0 +/- 3.1% and 77.9 +/- 2.6%, respectively, and an increase in Rt by 7.2 +/- 0.8%, n = 36. In conclusion, the RD2(NL) cell line presents the first model system in which CFTR-GCl is expressed in a purely absorptive tissue.(ABSTRACT TRUNCATED AT 250 WORDS)

  12. Experimental Studies of the Mechanism of Photon Absorption on Light Nuclei

    International Nuclear Information System (INIS)

    Steven Morrow

    2000-01-01

    A measurement of the reaction 12 C(γ,pγ(prime)) has been made with tagged photons in the range 49.47 γ - , 1/2 + , 5/2 + ) at E ex ≅ 7 MeV in the residual nucleus 11 B, following the reaction 12 C(γ,p), has been made by directly resolving their de-excitation γ-ray decay to the ground state of 11 B. This measurement constitutes the highest resolution ever achieved in determining the excitation function of the residual nucleus after a (γ,p) reaction (∼ 48 keV FWHM at E ex ≅ 7 MeV). Comparison has been made with the data of Kuzin et al, who also measured the relative populations with a resolution of ∼ 270 keV at E ex ≅ 7 MeV. The 7/2 - state at 6.74 MeV has been observed to be the most strongly excited state of the triplet in agreement with Kuzin et al. Disagreement has been found for the relative strengths of the 1/2 + and 5/2 + states in the triplet. An estimation of the maximum effect of angular correlations between the ejected proton and de-excitation γ-ray has been included in the analysis. This effect increases the disagreement between the measurements. A study of the reaction 12 C(e,e(prime)p) has been made in the missing momentum region 260 m L and W T . The experimental data have been compared with Complete Distorted Wave Impulse Approximation calculations and Random Phase Approximation calculations. The latter when including virtual photon absorption on 2-body currents (Meson Exchange Currents + Isobar Currents) are seen to describe the reduced cross sections better than 1-body current or Complete Distorted Wave Impulse Approximation calculations. For the 1st time a comparison between the 12 C(γ,p) reaction and the transverse part of 12 C(e,e(prime)p) reaction cross section has been made. This comparison suggests that the mechanism of the 2 reactions converge when both are studied in equivalent kinematics resolving the long standing issue of anomalous excitation of the ∼ 7 MeV triplet in 11 B, following 12 C(γ,p), not seen in the 12 C

  13. Theoretical study of the absorption spectrum and the thermochemistry of the CF{sub 3}OSO{sub 3} radical

    Energy Technology Data Exchange (ETDEWEB)

    Cobos, Carlos J.; Croce, Adela E. [Inst. de Investigaciones Fisicoquimicas Teoricas y Aplicadas (INIFTA), Univ. Nacional de La Plata, CCT La Plata-CONICET (Argentina)

    2010-08-15

    The UV-visible absorption spectrum of the recently reported CF{sub 3}OSO{sub 3} radical has been studied by using the time-dependent generalization of the density functional theory (TDDFT). For this a set of eleven hybrid functionals combined with the 6-311+G(3df) basis set were employed. The main features of the three experimental absorption bands of CF{sub 3}OSO{sub 3} recorded over the 220-530 nm range are well reproduced by the calculations. A dissociation enthalpy for the CF{sub 3}OSO{sub 3} bond of 19.1 kcal mol{sup -1} is predicted at the BAC-G3MP2//B3LYP/6-311+G(3df) level of theory. (orig.)

  14. Study of absorption and IR-emission of Er3+, Dy3+, Tm3+ doped high-purity tellurite glasses

    Science.gov (United States)

    Motorin, S. E.; Dorofeev, V. V.; Galagan, B. I.; Sverchkov, S. E.; Koltashev, V. V.; Denker, B. I.

    2018-04-01

    A study of high-purity TeO2-ZnO based tellurite glasses doped with Er3+, Dy3+ or Tm3+ that could be used as laser media in the 2-3 μm spectral range is presented. The glasses are prepared by melting the oxides mixture inside a silica glass reactor in an atmosphere of purified oxygen. The low level of hydroxyl groups absorption allowed to measure correctly the luminescence decay characteristics of the dopants. The rare-earth ions absorption bands, the luminescence spectra and kinetic characteristics of emission from the levels 4I11/2, 4I13/2 of Er3+, 6H13/2 of Dy3+ and 3H4, 3H5, 3F4 of Tm3+ ions are investigated. The results confirm the high potential of tellurite glasses as an active media for bulk, planar waveguide and fiber lasers.

  15. A furnace and temperature controller for optical absorption studies with a spectrophotometer

    International Nuclear Information System (INIS)

    Mariani Rogat, F.

    1975-01-01

    The design and main features of a furnace with a temperature controller and programmer are shown. This system allows to measure the optical absorption spectrum of a sample from room temperature to 400 deg C, in a double beam spectrophotometer Perkin Elmer 350. The sample temperature can be linearly increased at different heating rates between 4 and 38 deg C/min. The temperature ramp can be stopped at any desired point and the sample temperature shall be stabilized in less than one minute. This temperature shall be kept constant within 0.5 deg C for hours. The sample is heated in vacuum. (author)

  16. An x-ray absorption spectroscopy study of Cd binding onto a halophilic archaeon

    International Nuclear Information System (INIS)

    Showalter, Allison R; Bunker, Bruce A; Szymanowski, Jennifer E S; Fein, Jeremy B

    2016-01-01

    X-ray absorption spectroscopy (XAS) and cadmium (Cd) isotherm experiments determine how Cd adsorbs to the surface of halophilic archaeon Halobacterium noricense . This archaeon, isolated from the Waste Isolation Pilot Plant (WIPP) near Carlsbad, New Mexico could be involved with the transport of toxic metals stored in the transuranic waste in the salt mine. The isotherm experiments show that adsorption is relatively constant across the tolerable pH range for H. noricense . The XAS results indicate that Cd adsorption occurs predominately via a sulfur site, most likely sulfhydryl, with the same site dominating all measured pH values. (paper)

  17. An x-ray absorption spectroscopy study of Cd binding onto a halophilic archaeon

    Science.gov (United States)

    Showalter, Allison R.; Szymanowski, Jennifer E. S.; Fein, Jeremy B.; Bunker, Bruce A.

    2016-05-01

    X-ray absorption spectroscopy (XAS) and cadmium (Cd) isotherm experiments determine how Cd adsorbs to the surface of halophilic archaeon Halobacterium noricense. This archaeon, isolated from the Waste Isolation Pilot Plant (WIPP) near Carlsbad, New Mexico could be involved with the transport of toxic metals stored in the transuranic waste in the salt mine. The isotherm experiments show that adsorption is relatively constant across the tolerable pH range for H. noricense. The XAS results indicate that Cd adsorption occurs predominately via a sulfur site, most likely sulfhydryl, with the same site dominating all measured pH values.

  18. Strontium Localization in Bone Tissue Studied by X-Ray Absorption Spectroscopy

    DEFF Research Database (Denmark)

    Frankær, Christian Grundahl; Raffalt, Anders Christer; Ståhl, Kenny

    2014-01-01

    Strontium has recently been introduced as a pharmacological agent for the treatment and prevention of osteoporosis. We determined the localization of strontium incorporated into bone matrix from dogs treated with Sr malonate by X-ray absorption spectroscopy. A new approach for analyzing the X...... highly ordered sites, and at least 30 % is located at less ordered sites where only the first solvation shell is resolved, suggesting that strontium is sur- rounded by only oxygen atoms similar to Sr2? in solution. Strontium was furthermore shown to be absorbed in collagen in which it obtains a higher...

  19. Ultra-fast X-ray absorption spectroscopy for the study of matter in transient regime; Spectroscopie d'absorption ultra-rapide de rayonnement X pour l'etude de la matiere en regime transitoire

    Energy Technology Data Exchange (ETDEWEB)

    Lecherbourg, L

    2007-12-15

    In this work, we study the physics of dense matter, plasmas or solids, using X-ray absorption spectroscopy. Through the use of sources produced by laser-matter interaction, we have measured the absorption spectra of aluminum and bromine plasmas, as well as those of vanadium dioxide (VO{sub 2}). The measurement of absorption coefficients allows us to probe the dense matter and to study its properties. The experiments are carried out following the same principle: they use the same experimental set-up, called pump-probe. When the matter is dense, the absorption properties of an atom are modified by the surrounding environment. In a plasma, it is mainly the bound- bound transitions which are altered: the shapes of those spectral rays are modified. In a solid, the position of the neighbouring atoms in relation to the absorbing atom modify the structure of absorption levels (bound-free transition). The study of this structure allows us to measure the parameters of the material, and provides information such as the state of the electronic band or the interatomic gaps. The experiments carried out at the LULI have allowed us to probe plasmas in the relatively unknown regime of the Warm Dense Matter. One of the key parameters is that the plasma is characterised independently (FDI diagnostic). It allows for a better comparison of the measured absorption against a calculation made with the numerical model OPA-S. The experiments carried out at INRS have led to the realisation of an experimental system having the characteristics which allow the study of the dynamics of solids showing ultra-fast phase transition. For those experiments, we have used vanadium dioxide as a model system allowing us to test the feasibility of the method. (author)

  20. CHARACTERIZATION OF PHYSICOCHEMICAL PROPERTIES OF MISCANTHUS FLORIDULUS STEMS AND STUDY OF THEIR OIL ABSORPTION ABILITY USING GOLD NANOPARTICLES

    Directory of Open Access Journals (Sweden)

    Wayne Liao,

    2012-07-01

    Full Text Available Miscanthus floridulus, which originated from a high elevation mountain area in Taiwan, is a newly cultivated species of Miscanthus. Instead of Miscanthus × giganteus, M. floridulus can be used as an alternative fuel for energy production as well. Except for leaves, stems of M. floridulus count for a major portion of the biomass. In this study, the lignin and cellulose contents of M. floridulus stems were determined to be 22.33 ± 2.21% and 43.13 ± 2.79%, respectively. In addition, a new application of M. floridulus stems was proposed. Oil absorption ability represented by the amount of soybean and motor oils absorbed by one gram of pulverized M. floridulus stems was estimated to be 2.25 ± 0.25 and 2.33 ± 0.18 g, respectively. Gold nanoparticles were used to investigate the absorption ability of M. floridulus stems. The absorption of gold nanoparticles by M. floridulus stems was visualized using SEM and TEM. In addition, the IR spectrum of M. floridulus stems was recorded for comparison with other studies.

  1. Infrared study of the absorption edge of β-InN films grown on GaN/MgO structures

    Science.gov (United States)

    Pérez-Caro, M.; Rodríguez, A. G.; Vidal, M. A.; Navarro-Contreras, H.

    2010-07-01

    Infrared optical studies were carried out in a group of cubic InN samples grown by gas source molecular beam epitaxy on MgO (001) substrates. Room temperature (RT) reflectance and low-temperature (LT) transmittance measurements were performed by using fast Fourier transform infrared spectrometry. Reflectance fittings allowed to establish that β-InN films have large free-carrier concentrations present (>1019 cm-3), a result that is corroborated by Hall effect measurements. Each sample explored exhibited a different optical absorption edge. The Varshni parameters that describe adequately the optical absorption edge responses with temperature are obtained for the set of samples studied. The observed temperatures changes, from LT to RT, are the lowest reported for III-V semiconductor binary compounds. The temperature coefficient of the conduction band depends on the strength of the electron-phonon interaction (e-ph-i), as well as on the thermal expansion. It has been predicted that cubic InN has one of the smallest e-ph-i of all III-V compounds, which is corroborated by these results. The variation in values of absorption edges is clearly consistent with the Burstein-Moss and band renormalization effects, produced by high free electron concentrations. It is shown that the conduction band in β-InN, analogous to wurtzite InN, follows a nonparabolic behavior.

  2. X-ray absorption spectroscopic studies of the active sites of nickel- and copper-containing metalloproteins

    International Nuclear Information System (INIS)

    Tan, G.O.

    1993-06-01

    X-ray absorption spectroscopy (XAS) is a useful tool for obtaining structural and chemical information about the active sites of metalloproteins and metalloenzymes. Information may be obtained from both the edge region and the extended X-ray absorption fine structure (EXAFS) or post-edge region of the K-edge X-ray absorption spectrum of a metal center in a compound. The edge contains information about the valence electronic structure of the atom that absorbs the X-rays. It is possible in some systems to infer the redox state of the metal atom in question, as well as the geometry and nature of ligands connected to it, from the features in the edge in a straightforward manner. The EXAFS modulations, being produced by the backscattering of the ejected photoelectron from the atoms surrounding the metal atom, provide, when analyzed, information about the number and type of neighbouring atoms, and the distances at which they occur. In this thesis, analysis of both the edge and EXAFS regions has been used to gain information about the active sites of various metalloproteins. The metalloproteins studied were plastocyanin (Pc), laccase and nickel carbon monoxide dehydrogenase (Ni CODH). Studies of Cu(I)-imidazole compounds, related to the protein hemocyanin, are also reported here

  3. Validation of phenol red versus gravimetric method for water reabsorption correction and study of gender differences in Doluisio's absorption technique.

    Science.gov (United States)

    Tuğcu-Demiröz, Fatmanur; Gonzalez-Alvarez, Isabel; Gonzalez-Alvarez, Marta; Bermejo, Marival

    2014-10-01

    The aim of the present study was to develop a method for water flux reabsorption measurement in Doluisio's Perfusion Technique based on the use of phenol red as a non-absorbable marker and to validate it by comparison with gravimetric procedure. The compounds selected for the study were metoprolol, atenolol, cimetidine and cefadroxil in order to include low, intermediate and high permeability drugs absorbed by passive diffusion and by carrier mediated mechanism. The intestinal permeabilities (Peff) of the drugs were obtained in male and female Wistar rats and calculated using both methods of water flux correction. The absorption rate coefficients of all the assayed compounds did not show statistically significant differences between male and female rats consequently all the individual values were combined to compare between reabsorption methods. The absorption rate coefficients and permeability values did not show statistically significant differences between the two strategies of concentration correction. The apparent zero order water absorption coefficients were also similar in both correction procedures. In conclusion gravimetric and phenol red method for water reabsorption correction are accurate and interchangeable for permeability estimation in closed loop perfusion method. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Do we still need to collect stool? Evaluation of visualized fatty acid absorption: experimental studies using rats.

    Science.gov (United States)

    Chiba, T; Ohi, R

    1998-01-01

    Short-gut syndrome is likely to impair enteric fat utilization. This study was undertaken to develop a clinical test of lipid absorption without fecal collection. The absorption of enterally fed radioactive long-chain fatty acid, beta-methyl-p-(123I)-iodophenylpentadecanoic acid was investigated with continuous chyle collection in rats. The changes in excretion and time-dependent biodistribution of radioactivity of the enterally fed agent were assessed in normal control animals. Similarly, sequential urinary excretion and biodistribution were studied along with scintigraphy using sham-operated and short-gut animals. Approximately 64% of the enterally fed radioactivity was recovered in the collected chyle (24 hours). A comparison of normal control, sham-operated, and short-gut animals showed significantly less urinary and greater fecal excretions of radioactivity in short-gut animals. With the use of sequential scintigraphy, the small intestine, whole-body soft tissues, and urinary bladder were well visualized in sham-operated animals, whereas the large intestine and feces were demonstrated earlier in short-gut animals. Our results suggest that enteral feeding of the agent might be feasible for determining lipid absorption from the the dynamic changes of radioactivity in visualized abdominal organs and in urine.

  5. Infrared study of the absorption edge of β-InN films grown on GaN/MgO structures

    International Nuclear Information System (INIS)

    Perez-Caro, M.; Rodriguez, A. G.; Vidal, M. A.; Navarro-Contreras, H.

    2010-01-01

    Infrared optical studies were carried out in a group of cubic InN samples grown by gas source molecular beam epitaxy on MgO (001) substrates. Room temperature (RT) reflectance and low-temperature (LT) transmittance measurements were performed by using fast Fourier transform infrared spectrometry. Reflectance fittings allowed to establish that β-InN films have large free-carrier concentrations present (>10 19 cm -3 ), a result that is corroborated by Hall effect measurements. Each sample explored exhibited a different optical absorption edge. The Varshni parameters that describe adequately the optical absorption edge responses with temperature are obtained for the set of samples studied. The observed temperatures changes, from LT to RT, are the lowest reported for III-V semiconductor binary compounds. The temperature coefficient of the conduction band depends on the strength of the electron-phonon interaction (e-ph-i), as well as on the thermal expansion. It has been predicted that cubic InN has one of the smallest e-ph-i of all III-V compounds, which is corroborated by these results. The variation in values of absorption edges is clearly consistent with the Burstein-Moss and band renormalization effects, produced by high free electron concentrations. It is shown that the conduction band in β-InN, analogous to wurtzite InN, follows a nonparabolic behavior.

  6. Extended x-ray absorption fine structure studies of amorphous and crystalline Si-Ge alloys with synchrotron radiation

    International Nuclear Information System (INIS)

    Kajiyama, Hiroshi

    1988-01-01

    Extended X-ray absorption fine structure (EXAFS) is a powerful probe to study the local structure around the atom of a specific element. In conventional EXAFS analysis, it has been known that reliable structures are obtained with the different values of absorption edge energy for different neighboring atoms. It is shown in this study that the Ge-K edge EXAFS resulting from the Ge-Ge and Ge-Si bonds in hydrogenated amorphous Si-Ge alloys was able to be excellently explained by a unique absorption edge energy value, provided that a newly developed formula based on the spherical wave function of photoelectrons is used. The microscopic structures of hydrogenated amorphous Si-Ge alloys and crystalline Si-Ge alloys have been determined using the EXAFS method. The lengths of Ge-Ge and Ge-Si bonds were constant throughout their entire composition range, and it was found that the length of Ge-Si bond was close to the average value of the bond lengths of both Ge and Si crystals. In crystalline Si-Ge alloys, it has been shown that the bonds relaxed completely, while the lattice constant varied monotonously with the composition. (Kako, I.)

  7. Total photon absorption

    International Nuclear Information System (INIS)

    Carlos, P.

    1985-06-01

    The present discussion is limited to a presentation of the most recent total photonuclear absorption experiments performed with real photons at intermediate energy, and more precisely in the region of nucleon resonances. The main sources of real photons are briefly reviewed and the experimental procedures used for total photonuclear absorption cross section measurements. The main results obtained below 140 MeV photon energy as well as above 2 GeV are recalled. The experimental study of total photonuclear absorption in the nuclear resonance region (140 MeV< E<2 GeV) is still at its beginning and some results are presented

  8. Combining X-ray Absorption and X-ray Diffraction Techniques for in Situ Studies of Chemical Transformations in Heterogeneous Catalysis: Advantages and Limitations

    International Nuclear Information System (INIS)

    Frenkel, A.I.; Hanson, J.; Wang, Q.; Marinkovic, N.; Chen, J.G.; Barrio, L.; Si, R.; Lopez Camara, A.; Estrella, A.M.; Rodriguez, J.A.

    2011-01-01

    Recent advances in catalysis instrumentations include synchrotron-based facilities where time-resolved X-ray scattering and absorption techniques are combined in the same in situ or operando experiment to study catalysts at work. To evaluate the advances and limitations of this method, we performed a series of experiments at the new XAFS/XRD instrument in the National Synchrotron Light Source. Nearly simultaneous X-ray diffraction (XRD) and X-ray absorption fine-structure (XAFS) measurements of structure and kinetics of several catalysts under reducing or oxidizing conditions have been performed and carefully analyzed. For CuFe 2 O 4 under reducing conditions, the combined use of the two techniques allowed us to obtain accurate data on kinetics of nucleation and growth of metallic Cu. For the inverse catalyst CuO/CeO 2 that underwent isothermal reduction (with CO) and oxidation (with O 2 ), the XAFS data measured in the same experiment with XRD revealed strongly disordered Cu species that went undetected by diffraction. These and other examples emphasize the unique sensitivity of these two complementary methods to follow catalytic processes in the broad ranges of length and time scales.

  9. Ab-initio study on the absorption spectrum of color change sapphire based on first-principles calculations with considering lattice relaxation-effect

    Science.gov (United States)

    Novita, Mega; Nagoshi, Hikari; Sudo, Akiho; Ogasawara, Kazuyoshi

    2018-01-01

    In this study, we performed an investigation on α-Al2O3: V3+ material, or the so-called color change sapphire, based on first-principles calculations without referring to any experimental parameter. The molecular orbital (MO) structure was estimated by the one-electron MO calculations using the discrete variational-Xα (DV-Xα) method. Next, the absorption spectra were estimated by the many-electron calculations using the discrete variational multi-electron (DVME) method. The effect of lattice relaxation on the crystal structures was estimated based on the first-principles band structure calculations. We performed geometry optimizations on the pure α-Al2O3 and with the impurity V3+ ion using Cambridge Serial Total Energy Package (CASTEP) code. The effect of energy corrections such as configuration dependence correction and correlation correction was also investigated in detail. The results revealed that the structural change on the α-Al2O3: V3+ resulted from the geometry optimization improved the calculated absorption spectra. By a combination of both the lattice relaxation-effect and the energy correction-effect improve the agreement to the experiment fact.

  10. X-ray absorption spectroscopic studies of the dinuclear iron center in methane monooxygenase and the sulfure and chlorine centers in photographic materials

    Energy Technology Data Exchange (ETDEWEB)

    DeWitt, J.G.

    1992-12-01

    The dinuclear iron center of the hydroxylase component of soluble methane monooxygenase (MMO) from Methylococcus capsulatus and Methylosinus trichosporiwn has been studied by X-ray absorption spectroscopy. Analysis of the Fe K-edge EXAFS revealed that the first shell coordination of the Fe(HI)Fe(IH) oxidized state of the hydroxylase from M. capsulatus consists of approximately 6 N and 0 atoms at an average distance of 2.04 [Angstrom]. The Fe-Fe distance was determined to be 3.4 [Angstrom]. No evidence for the presence of a short oxo bridge in the iron center of the oxidized hydroxylase was found, suggesting that the active site of MMO is significantly different from the active sites of the dinuclear iron proteins hemery and ribonucleotide reductase. In addition, the results of the first shell fits suggest that there are more oxygen than nitrogen donor ligands.

  11. X-ray absorption spectroscopic studies of the dinuclear iron center in methane monooxygenase and the sulfure and chlorine centers in photographic materials

    Energy Technology Data Exchange (ETDEWEB)

    DeWitt, Jane G. [Stanford Univ., CA (United States)

    1992-12-01

    The dinuclear iron center of the hydroxylase component of soluble methane monooxygenase (MMO) from Methylococcus capsulatus and Methylosinus trichosporiwn has been studied by X-ray absorption spectroscopy. Analysis of the Fe K-edge EXAFS revealed that the first shell coordination of the Fe(HI)Fe(IH) oxidized state of the hydroxylase from M. capsulatus consists of approximately 6 N and 0 atoms at an average distance of 2.04 Å. The Fe-Fe distance was determined to be 3.4 Å. No evidence for the presence of a short oxo bridge in the iron center of the oxidized hydroxylase was found, suggesting that the active site of MMO is significantly different from the active sites of the dinuclear iron proteins hemery and ribonucleotide reductase. In addition, the results of the first shell fits suggest that there are more oxygen than nitrogen donor ligands.

  12. Biological X-ray absorption spectroscopy (BioXAS): a valuable tool for the study of trace elements in the life sciences.

    Science.gov (United States)

    Strange, Richard W; Feiters, Martin C

    2008-10-01

    Using X-ray absorption spectroscopy (XAS) the binding modes (type and number of ligands, distances and geometry) and oxidation states of metals and other trace elements in crystalline as well as non-crystalline samples can be revealed. The method may be applied to biological systems as a 'stand-alone' technique, but it is particularly powerful when used alongside other X-ray and spectroscopic techniques and computational approaches. In this review, we highlight how biological XAS is being used in concert with crystallography, spectroscopy and computational chemistry to study metalloproteins in crystals, and report recent applications on relatively rare trace elements utilised by living organisms and metals involved in neurodegenerative diseases.

  13. Optimization study of distillation column based on Type I absorption heat pump

    International Nuclear Information System (INIS)

    Li, Yan; Wang, Lu; Zhu, Meng; Wang, Weiqin

    2017-01-01

    Highlights: • Propose a new distillation system based on Type I absorption heat pump. • The optimum condition of the system is obtained. • The energy consumption of the system is reduced by 23.3% significantly. • The benefits of economy and energy-saving for the new distillation system are distinct. - Abstract: Due to the thermodynamic deficiencies in general pressurized distillation process, a new distillation system based on Type I AHP (absorption heat pump) is proposed in this paper. The proposed system uses AHP to recover the waste heat from column condenser and reheat the feed materials of column; meanwhile, the cooling capacity of column condenser can be increased, which leads to the decrease of the pressure in distillation column. With general distillation system of depropanizing column (C-101) as an example, using numerical simulation software Aspen Plus, the effect of inner parameters on the energy consumption has been conducted to approach the general rules of energy saving in distillation. Then the new distillation system is adopted and the optimization of its energy consumption is conducted to determine the optimum operating condition. The numerical simulation results show that the steam consumption can be decreased by 23.3% compared with general C-101 system, reaching the minimum. Moreover, the extra heat output of AHP is treated as the heat source for the reboilers of deethanization column (C-102) and refined propylene column (C-103), which reduces the total steam consumption of three-column processes by 22.1%.

  14. Structural analysis of radiation damage in zircon and thorite: An X-ray absorption spectroscopic study

    International Nuclear Information System (INIS)

    Farges, F.; Calas, G.

    1991-01-01

    Metamictization effects have been investigated in zircon, thorite, uranothorite, and thorogummite using X-ray absorption spectroscopy at Zr-K, Th-L III edges. Extended X-ray absorption fine structure (EXAFS) spectra of metamict samples are characterized by a major contribution due to the O nearest neighbors with some contributions from next-nearest neighbors (Si and Zr in zircon, Si in thorite). In zircon, Zr-O distances decrease by ∼0.1 angstrom while the coordination number of Zr decreases from 8 to 7. In contrast, the eightfold coordination of Th in crystalline thorite is preserved in metamict thorite, Si second neighbors around Zr or Th are generally observed in metamict samples with distances close to those measured in crystalline phases. No other contribution to EXAFS is observed in thorite, but Zr-Zr distances are observed in zircon. They decrease by ca. 0.3 Angstrom as a function of zircon metamictization. Metamictization processes are characterized by a loss of medium range order. There is no evidence for decomposition into crystalline oxides. The structural interpretation of EXAFS data must take into account the creation of O vacancies arising from a displacement or tilting of the SiO 4 tetrahedra during metamictization of zircon-like structures. If the cation can take a lower coordination number (as in the case of Zr), a coordination change allows the local structure to be partly maintained during metamictization. If not, as for Th, the local structure is rapidly destroyed

  15. Use of partial AUC (PAUC) to evaluate bioequivalence--a case study with complex absorption: methylphenidate.

    Science.gov (United States)

    Fourie Zirkelbach, Jeanne; Jackson, Andre J; Wang, Yaning; Schuirmann, Donald J

    2013-01-01

    Methylphenidate modified-release products produce early and late peak concentrations critical for treatment of morning and afternoon symptoms of attention deficit hyperactivity disorder (ADHD). Standard bioequivalence (BE) criteria cannot be applied to these products. The performance of partial area under the drug concentration-time curve (PAUC), Cmax and AUCINF to assess BE were independently evaluated for two products. A two-stage analysis was performed on plasma data for two methylphenidate modified-release products (Product 1 and 2). Simulations using the fitted parameters determined how changes in fast absorption rate constant (K0Fast) and fraction available (F1) affected curve shape and BE determination using Cmax, AUCINF and PAUC. The sensitivity of the mean PAUC(test)/PAUC(reference) ratios to changes in K0Fast(test) are product dependent. Product 1 mean PAUC(test)/PAUC(reference) ratios for PAUC0-4h are more responsive to both decreases and increases in K0Fast(test) than Product 2. Product 2 showed a greater response in the mean PAUC(test)/PAUC(reference) ratio for PAUC0-4h when the K0Fast(test) is decreased and less response as the value is increased. PAUC estimated curve shape is sensitive to changes in absorption and are product specific, and may require a new PAUC metric for each drug. A non-product specific metric to assess curve shape is warranted.

  16. Red-light absorption and fluorescence of phytochrome chromophores: A comparative theoretical study

    Energy Technology Data Exchange (ETDEWEB)

    Falklöf, Olle; Durbeej, Bo, E-mail: bodur@ifm.liu.se

    2013-11-08

    Highlights: • Calculation of red-light absorption and emission of phytochrome chromophores. • Comparison of TD-DFT and ab initio methods. • Pure functionals show better accuracy than hybrid functionals. - Abstract: Currently, much experimental effort is being invested in the engineering of phytochromes, a large superfamily of photoreceptor proteins, into fluorescent proteins suitable for bioimaging in the near-infrared regime. In this work, we gain insight into the potential of computational methods to contribute to this development by investigating how well representative quantum chemical methods reproduce recently recorded red-light absorption and emission maxima of synthetic derivatives of the bilin chromophores of phytochromes. Focusing on the performance of time-dependent density functional theory but using also the ab initio CIS(D), CC2 and CASPT2 methods, we explore how various methodological considerations influence computed spectra and find, somewhat surprisingly, that density functionals lacking exact exchange reproduce the experimental measurements with smaller errors than functionals that include exact exchange. Thus, for the important class of chromophores that bilins constitute, the widely established trend that hybrid functionals give more accurate excitation energies than pure functionals does not apply.

  17. Studies on the percutaneous absorption of 14C-labelled Flurbiprofen, 3

    International Nuclear Information System (INIS)

    Nagao, Soshichi; Sakai, Takeo; Hayakawa, Toru

    1983-01-01

    Whole body autoradiography was carried out to clarify and compare the distribution of 14 C-labelled Flurbiprofen which was applied to the skin as an ointment in rats and guinea-pigs. Both in rats and guinea-pigs almost the same autoradiogram was gained. The radioactivity was strongest at the skin area inspite of the time elapse, showing that the drug was fixed in the site of skin applied. In other parts of the body, however, it was small except the kidney and intestine. It seemed that the absorption of the drug was a little although the migration of the drug into the blood circulation as fast at the beginning as was shown in pigs previously. A storonger radioactivity in the kidney and intestine might indicate that a main pathway of excretion of this drug was through those two organs. Absorption, distribution and excretion of the drug were not different between rats and guinea-pigs, similar to those observed in pigs. (author)

  18. Computational Studies of Drug Release, Transport and Absorption in the Human Intestines

    Science.gov (United States)

    Behafarid, Farhad; Brasseur, J. G.; Vijayakumar, G.; Jayaraman, B.; Wang, Y.

    2016-11-01

    Following disintegration of a drug tablet, a cloud of particles 10-200 μm in diameter enters the small intestine where drug molecules are absorbed into the blood. Drug release rate depends on particle size, solubility and hydrodynamic enhancements driven by gut motility. To quantify the interrelationships among dissolution, transport and wall permeability, we apply lattice Boltzmann method to simulate the drug concentration field in the 3D gut released from polydisperse distributions of drug particles in the "fasting" vs. "fed" motility states. Generalized boundary conditions allow for both solubility and gut wall permeability to be systematically varied. We apply a local 'quasi-steady state' approximation for drug dissolution using a mathematical model generalized for hydrodynamic enhancements and heterogeneity in drug release rate. We observe fundamental differences resulting from the interplay among release, transport and absorption in relationship to particle size distribution, luminal volume, motility, solubility and permeability. For example, whereas smaller volume encourages higher bulk concentrations and reduced release rate, it also encourages higher absorption rate, making it difficult to generalize predictions. Supported by FDA.

  19. Clustering of germanium atoms in silica glass responsible for the 3.1 eV emission band studied by optical absorption and X-ray absorption fine structure analysis

    International Nuclear Information System (INIS)

    Yoshida, Tomoko; Muto, Shunsuke; Yuliati, Leny; Yoshida, Hisao; Inada, Yasuhiro

    2009-01-01

    Correlation between the 3.1 eV emission band and local atomic configuration was systematically examined for Ge + implanted silica glass by UV-vis optical absorption spectroscopy and X-ray absorption fine structure (XAFS) analysis. The 2.7 eV emission band, commonly observed in defective silica, was replaced by the sharp and intense 3.1 eV emission band for the Ge + fluence > 2 x 10 16 cm -2 , in which UV-vis absorption spectra suggested clustering of Ge atoms with the size ∼1 nm. XAFS spectroscopy indicated that the Ge atoms were under coordinated with oxygen atoms nearly at a neutral valence state on average. The present results are consistent with the previous ESR study but imply that the small Ge clusters rather than the O=Ge: complexes (point defects) are responsible for the 3.1 eV emission band.

  20. A study of the Nb3Ge system by Ge K-edge extended x-ray absorption fine structure and x-ray absorption near-edge structure spectroscopy

    International Nuclear Information System (INIS)

    Saini, N L; Filippi, M; Wu Ziyu; Oyanagi, H; Ihara, H; Iyo, A; Agrestini, S; Bianconi, A

    2002-01-01

    The local structure of Nb 3 Ge intermetallic superconductor has been studied by Ge K-edge absorption spectroscopy. Extended x-ray absorption fine structure (EXAFS) experiments show two Ge-Nb distances. In addition to the crystallographic distance of ∼2.87 A, there exists a second Ge-Nb distance, shorter than the first by ∼0.2 A, assigned to a phase with short-range symmetry related to local displacements in the Nb-Nb chains. The x-ray absorption near-edge structure (XANES) spectrum has been simulated by full multiple-scattering calculations considering the local displacements determined by the EXAFS analysis. The XANES spectrum has been well reproduced by considering a cluster of 99 atoms within a radius of about 7 A from the central Ge atom and introducing determined local displacements

  1. Study on Energy Absorption Capacity of Steel-Polyester Hybrid Fiber Reinforced Concrete Under Uni-axial Compression

    Science.gov (United States)

    Chella Gifta, C.; Prabavathy, S.

    2018-05-01

    This work presents the energy absorption capacity of hybrid fiber reinforced concrete made with hooked end steel fibers (0.5 and 0.75%) and straight polyester fibers (0.5, 0.8, 1.0 and 2.0%). Compressive toughness (energy absorption capacity) under uni-axial compression was evaluated on 100 × 200 mm size cylindrical specimens with varying steel and polyester fiber content. Efficiency of the hybrid fiber reinforcement is studied with respect to fiber type, size and volume fractions in this investigation. The vertical displacement under uni-axial compression was measured under the applied loads and the load-deformation curves were plotted. From these curves the toughness values were calculated and the results were compared with steel and polyester as individual fibers. The hybridization of 0.5% steel + 0.5% polyester performed well in post peak region due to the addition of polyester fibers with steel fibers and the energy absorption value was 23% greater than 0.5% steel FRC. Peak stress values were also higher in hybrid series than single fiber and based on the results it is concluded that hybrid fiber reinforcement improves the toughness characteristics of concrete without affecting workability.

  2. Comparative studies of method for determining total mercury in fish. Dithizone and flameless atomic absorption spectrophotometry techniques

    International Nuclear Information System (INIS)

    Protasowicki, M.; Ociepa, A.; Chodyniecki, A.

    1977-01-01

    Two methods for determining total mercury in fish were compared: the dithizone and flameless atomic absorption spectrophotometry techniques. The studies involved determination of recovery when 1μg of mercury as solutions of HgCl 2 or CH 3 HgC were added to each sample of herring flesh. Mean recoveries in the dithizone method were found to be 91.4+-7.47% and 90.25+-4.73% for the two solutions respectively, while the recoveries obtained with the flameless atomic absorption spectrophotometry were 95.00+-9.13% and 98.70+-7.14%, respectively. Both techniques were used to determine the mercury content in the same herring flesh sample. The first technique showed the content of 0.050+-0.018μg Hg g -1 while the result obtained with the other one was 0.062+-0.013μg Hg g -1 . The statistical treatment of the results obtained showed no difference between the two techniques, the significance level being α=0.05. Therefore, the results obtained with the dithizone method are comparable with those obtained with the flameless atomic absorption spectrophotometry for mercury contents of the magnitude order of 0.050 ug.g -1 . (author)

  3. Delayed electron relaxation in CdTe nanorods studied by spectral analysis of the ultrafast transient absorption

    Energy Technology Data Exchange (ETDEWEB)

    Kriegel, I., E-mail: ilka.kriegel@iit.it [Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy); Scotognella, F. [Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy); CNST of IIT@POLIMI, Via Pascoli 70/3, 20133 Milano (Italy); Soavi, G. [Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy); Brescia, R. [Department of Nanochemistry, Istituto Italiano di Tecnologia (IIT), via Morego 30, 16163 Genova (Italy); Rodríguez-Fernández, J.; Feldmann, J. [Photonics and Optoelectronics Group, Department of Physics and CeNS, Ludwig-Maximilians-Universität München, Amalienstr. 54, 80799 Munich (Germany); Nanosystems Initiative Munich (NIM), Schellingstr. 4, 80799 Munich (Germany); Lanzani, G., E-mail: guglielmo.lanzani@iit.it [Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy); CNST of IIT@POLIMI, Via Pascoli 70/3, 20133 Milano (Italy); Tassone, F. [CNST of IIT@POLIMI, Via Pascoli 70/3, 20133 Milano (Italy)

    2016-06-01

    Highlights: • We study the photophysics of CdTe nanorods by ultrafast absorption spectroscopy. • We fit photobleaching and photoinduced absorption features at all time delays. • Dynamics are extracted from superpositions of bleaches (Gaussians) and derivatives. • Fast non-radiative recombination and slower hole trapping processes are extracted. • A potential approach to unveil ultrafast non-radiative recombination processes. - Abstract: In transient absorption (TA) spectra, the bleach features originating from state filling are overlapped by their energy-shifted derivatives, arising from excited state energy level shifts. This makes the direct extraction of carrier dynamics from a single-wavelength time-trace misleading. Fitting TA spectra in time, as Gaussian functions and their derivative-like shifted Gaussians, allows to individually extract the real dynamics of both photobleached transitions, and their energy shifts. In CdTe nanorods (NRs) we found a delayed heating of holes due to the release of the large excess energy in the electron relaxation process. The slow hole-trapping process is consistent with a high number of surface trap states in these model NRs. Our results show that only a correct disentanglement of bleaching and energy shift contributions provides a reliable framework to extract the underlying carrier relaxation dynamics, including trapping, non-radiative recombination, and eventually carrier multiplication.

  4. Oral absorption of peptides and nanoparticles across the human intestine: Opportunities, limitations and studies in human tissues.

    Science.gov (United States)

    Lundquist, P; Artursson, P

    2016-11-15

    In this contribution, we review the molecular and physiological barriers to oral delivery of peptides and nanoparticles. We discuss the opportunities and predictivity of various in vitro systems with special emphasis on human intestine in Ussing chambers. First, the molecular constraints to peptide absorption are discussed. Then the physiological barriers to peptide delivery are examined. These include the gastric and intestinal environment, the mucus barrier, tight junctions between epithelial cells, the enterocytes of the intestinal epithelium, and the subepithelial tissue. Recent data from human proteome studies are used to provide information about the protein expression profiles of the different physiological barriers to peptide and nanoparticle absorption. Strategies that have been employed to increase peptide absorption across each of the barriers are discussed. Special consideration is given to attempts at utilizing endogenous transcytotic pathways. To reliably translate in vitro data on peptide or nanoparticle permeability to the in vivo situation in a human subject, the in vitro experimental system needs to realistically capture the central aspects of the mentioned barriers. Therefore, characteristics of common in vitro cell culture systems are discussed and compared to those of human intestinal tissues. Attempts to use the cell and tissue models for in vitro-in vivo extrapolation are reviewed. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  5. Delayed electron relaxation in CdTe nanorods studied by spectral analysis of the ultrafast transient absorption

    International Nuclear Information System (INIS)

    Kriegel, I.; Scotognella, F.; Soavi, G.; Brescia, R.; Rodríguez-Fernández, J.; Feldmann, J.; Lanzani, G.; Tassone, F.

    2016-01-01

    Highlights: • We study the photophysics of CdTe nanorods by ultrafast absorption spectroscopy. • We fit photobleaching and photoinduced absorption features at all time delays. • Dynamics are extracted from superpositions of bleaches (Gaussians) and derivatives. • Fast non-radiative recombination and slower hole trapping processes are extracted. • A potential approach to unveil ultrafast non-radiative recombination processes. - Abstract: In transient absorption (TA) spectra, the bleach features originating from state filling are overlapped by their energy-shifted derivatives, arising from excited state energy level shifts. This makes the direct extraction of carrier dynamics from a single-wavelength time-trace misleading. Fitting TA spectra in time, as Gaussian functions and their derivative-like shifted Gaussians, allows to individually extract the real dynamics of both photobleached transitions, and their energy shifts. In CdTe nanorods (NRs) we found a delayed heating of holes due to the release of the large excess energy in the electron relaxation process. The slow hole-trapping process is consistent with a high number of surface trap states in these model NRs. Our results show that only a correct disentanglement of bleaching and energy shift contributions provides a reliable framework to extract the underlying carrier relaxation dynamics, including trapping, non-radiative recombination, and eventually carrier multiplication.

  6. Study of influencing factors to chromophoric dissolved organic matter absorption properties from fluorescence features in Taihu lake in autumn

    Directory of Open Access Journals (Sweden)

    Chuang-Chun Huang

    2013-04-01

    Full Text Available In order to identify the components of chromophoric dissolved organic matter (CDOM, confirm the influence of components to the absorption coefficient of CDOM (aCDOM, and estimate aCDOM from fluorescence spectra, fluorescence and optical measurements of CDOM were carried out in November 2008. The results indicate that, the primary component of CDOM is humic-like. The secondary component is tryptophan-like, which is the product of phytoplankton and aquatic debris rather than the wastewater treatment drainaged from city. In this study, six fluorophores with multiple excitation-emission matrices (EEMs peaks (A, B, C, N, M, T were identified according to the parallel factor analysis (PARAFAC. The average contribution of each component to the CDOM is 19.93, 18.82, 16.88, 16.39, 12.26, and 15.72%, respectively. Red Shifted phenomenon will happen with the increase of fluorescence intensity for ultraviolet and terrestrially humic-like. Conversely, marine humic-like will appear Reverse Red Shifted with the increase of fluorescence intensity. The primary contributor to the shoulder value of CDOM’s absorption coefficient at 275 nm is phytoplankton productivity, followed by marine humic-like. The main contributors to the shoulder shape are UV humic-like and phytoplankton productivity, followed by marine humic-like and tryptophan-like. A strong correlation between CDOM absorption and fluorescence intensity at emission wavelength of 424 nm and excitation wavelength ranging from 280 to 360 nm was found. The absorption coefficient can be retrieved successfully from the same excitation wavelength’s fluorescence intensity by an exponential model.

  7. 2nd-order optical model of the isotopic dependence of heavy ion absorption cross sections for radiation transport studies

    Science.gov (United States)

    Cucinotta, Francis A.; Yan, Congchong; Saganti, Premkumar B.

    2018-01-01

    Heavy ion absorption cross sections play an important role in radiation transport codes used in risk assessment and for shielding studies of galactic cosmic ray (GCR) exposures. Due to the GCR primary nuclei composition and nuclear fragmentation leading to secondary nuclei heavy ions of charge number, Z with 3 ≤ Z ≥ 28 and mass numbers, A with 6 ≤ A ≥ 60 representing about 190 isotopes occur in GCR transport calculations. In this report we describe methods for developing a data-base of isotopic dependent heavy ion absorption cross sections for interactions. Calculations of a 2nd-order optical model solution to coupled-channel solutions to the Eikonal form of the nucleus-nucleus scattering amplitude are compared to 1st-order optical model solutions. The 2nd-order model takes into account two-body correlations in the projectile and target ground-states, which are ignored in the 1st-order optical model. Parameter free predictions are described using one-body and two-body ground state form factors for the isotopes considered and the free nucleon-nucleon scattering amplitude. Root mean square (RMS) matter radii for protons and neutrons are taken from electron and muon scattering data and nuclear structure models. We report on extensive comparisons to experimental data for energy-dependent absorption cross sections for over 100 isotopes of elements from Li to Fe interacting with carbon and aluminum targets. Agreement between model and experiments are generally within 10% for the 1st-order optical model and improved to less than 5% in the 2nd-order optical model in the majority of comparisons. Overall the 2nd-order optical model leads to a reduction in absorption compared to the 1st-order optical model for heavy ion interactions, which influences estimates of nuclear matter radii.

  8. Study of vitamin B/sub 12/ absorption by a whole-body counter (plastic). I. The fundamental considerations

    Energy Technology Data Exchange (ETDEWEB)

    Morishita, R; Furumatsu, C [Kyoto Univ. (Japan). Faculty of Medicine

    1975-08-01

    An absorption test of vitamin B/sub 12/ was studied by using the whole body spectrometer (plastic) in a low background room. Four plastic scintillation probes were set under the bed. Each plastic scintillation probe contains a 50x50x15 cm/sup 3/ scintillator and four photomultiplier tubes. Each subject was measured in supine and prone positions and the mean was used. Measurement was made before (body background), 35 minutes after (100%), and again 7 days after the oral administration of 0.17 to 0.2 ..mu..g(below 0.16 ..mu..Ci) /sup 60/Co-B/sub 12/ or of 0.2 ..mu..g(below 0.4 ..mu..Ci) /sup 58/Co-B/sub 12/. No meal or medicine was given at least 2 hours after the oral uptake of radioactive B/sub 12/. To correct for the radioactive decay and any counter instability, all measurements were corrected using a standard source. The results of B/sub 12/ absorption were expressed as the retention percentage of the labeled B/sub 12/ within the body on the seventh day. Present methods of measuring intestinal absorption of radioactive B/sub 12/ include measurements of the radioactivity (1) in the feces, (2) in the urine, (3) in the serum, or over the liver projection. While all these methods give clinically valuable results, B/sub 12/ absorption is determined most accurately by direct measurement of the amount remaining in the body with a whole-body counter after the unabsorbed radio-B/sub 12/ is excreted in the feces. It is more quantitative and simpler than the Schilling test and permits the measurement ofradioactive B/sub 12/ at a considerably lower level than the maximum permissible body burdens.

  9. Optical absorption in SrC4H4O6·3H2O crystals

    International Nuclear Information System (INIS)

    Arora, S.K.; Patel, Vipul; Kothari, Anjana; Chudasama, Bhupendra

    2004-01-01

    Study of optical absorption in the gel-grown strontium tartrate trihydrate (STT) single crystals measured in UV-vis range at room temperature reveals transitions involving absorption and emission of phonons. Based on the theory of interband optical absorptions, the electronic transition near the fundamental absorption edge is analysed. Some feeble disorder in the crystal is conceived to be present. The analysis carried out hereunder leads to estimation of energy of the lattice phonons involved

  10. A systematic parametric study and feasibility assessment of solar-assisted single-effect, double-effect, and triple-effect absorption chillers for heating and cooling applications

    International Nuclear Information System (INIS)

    Shirazi, Ali; Taylor, Robert A.; White, Stephen D.; Morrison, Graham L.

    2016-01-01

    Highlights: • TRNSYS simulations of SHC single/multi-effect absorption chillers were conducted. • A detailed parametric study was conducted to find the optimal size of the tank. • The effect of tank heat loss on the performance of the configurations was analyzed. • The effect of beam and diffuse radiation on the solar field size was investigated. • Energy performance and economics of each plant were analyzed in various climates. - Abstract: The present work investigates the feasibility of solar heating and cooling (SHC) absorption systems based on combining three types of LiBr–H_2O absorption chillers (single-, double-, and triple-effect) with common solar thermal collectors available on the market. A single-effect chiller is coupled with evacuated tube collectors (ETCs) – SHC1. A double-effect chiller is integrated with parabolic trough collectors (PTCs), linear Fresnel micro-concentrating collectors (MCTs) and evacuated flat plate collectors (EFPCs) respectively – SHC2, SHC3, and SHC4. PTCs are employed to provide high-temperature heat to a triple-effect absorption chiller (SHC5). Although triple-effect chillers have been around for a while, this paper represents the first system-level analysis of these chillers coupled with high-temperature solar concentrating collectors for air-conditioning applications. A simulation model for each configuration is developed in a transient system simulation environment (TRNSYS 17). Furthermore, a unique, comprehensive perspective is given by investigating the impact of characteristic solar beam radiation to global radiation ratios on the techno-economic performance of the proposed SHC plants for a wide variety of climatic regions worldwide. The results of parametric study suggest that a storage volume of around 70 L/m"2 is a good choice for SHC1, while 40–50 L/m"2 storage capacity is sufficient for the other configurations (SHC2 to SHC5). The simulation results reveal that when the fraction of direct normal

  11. X-ray absorption studies of chlorine valence and local environments in borosilicate waste glasses

    International Nuclear Information System (INIS)

    McKeown, David A.; Gan, Hao; Pegg, Ian L.; Stolte, W.C.; Demchenko, I.N.

    2011-01-01

    Chlorine (Cl) is a constituent of certain types of nuclear wastes and its presence can affect the physical and chemical properties of silicate melts and glasses developed for the immobilization of such wastes. Cl K-edge X-ray absorption spectra (XAS) were collected and analyzed to characterize the unknown Cl environments in borosilicate waste glass formulations, ranging in Cl-content from 0.23 to 0.94 wt.%. Both X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) data for the glasses show trends dependent on calcium (Ca) content. Near-edge data for the Ca-rich glasses are most similar to the Cl XANES of CaCl 2 , where Cl - is coordinated to three Ca atoms, while the XANES for the Ca-poor glasses are more similar to the mineral davyne, where Cl is most commonly coordinated to two Ca in one site, as well as Cl and oxygen nearest-neighbors in other sites. With increasing Ca content in the glass, Cl XANES for the glasses approach that for CaCl 2 , indicating more Ca nearest-neighbors around Cl. Reliable structural information obtained from the EXAFS data for the glasses is limited, however, to Cl-Cl, Cl-O, and Cl-Na distances; Cl-Ca contributions could not be fit to the glass data, due to the narrow k-space range available for analysis. Structural models that best fit the glass EXAFS data include Cl-Cl, Cl-O, and Cl-Na correlations, where Cl-O and Cl-Na distances decrease by approximately 0.16 A as glass Ca content increases. XAS for the glasses indicates Cl - is found in multiple sites where most Cl-sites have Ca neighbors, with oxygen, and possibly, Na second-nearest neighbors. EXAFS analyses suggest that Cl-Cl environments may also exist in the glasses in minor amounts. These results are generally consistent with earlier findings for silicate glasses, where Cl - was associated with Ca 2+ and Na + in network modifier sites.

  12. Optical absorption and fluorescence spectroscopy studies of Artepillin C, the major component of green propolis

    Science.gov (United States)

    Camuri, Isamara Julia; Costa, Adriano Batista; Ito, Amando Siuiti; Pazin, Wallance Moreira

    2018-06-01

    The bioactivity of propolis against several pathogens is well established, leading to the extensive consumption of that bee product to prevent diseases. Brazilian green propolis, collected by the species Apis mellifera, is one of the most consumed in the world. The chemical composition of green propolis is complex and it has been shown that it displays antioxidant, antimicrobial, anti-inflammatory and antitumor activities, especially due to the high content of Artepillin C. The molecule is a derivative of cinnamic acid with two prenylated groups, responsible for the improvement of the affinity of the compound for lipophilic environment. A carboxylic group (COOH) is also present in the molecule, making it a pH-sensitive compound and the pH-dependent structure of Artepillin C, may modulate its biological activity related to interactions with the cellular membrane of organisms and tissues. Molecular properties of Artepillin C on aqueous solution were examined by optical absorption, steady state and time-resolved fluorescence spectroscopies. Acid-base titration based on the spectral position of the near UV absorption band, resulted in the pKa value of 4.65 for the carboxylic group in Artepillin C. In acidic pH, below the pKa value, an absorption band raised around 350 nm at Artepillin C concentration above 50 μM, due to aggregation of the molecule. In neutral pH, with excitation at 310 nm, Artepillin C presents dual emission at 400 and 450 nm. In pH close to the pKa, the optical spectra show contribution from both protonated and deprotonated species. A three-exponential function was necessary to fit the intensity decays at the different pHs, dominated by a very short lifetime component, around 0.060 ns. The fast decay resulted in emission before fluorescence depolarization, and in values of fluorescence anisotropy higher than could be expected for monomeric forms of the compound. The results give fundamental knowledge about the protonation-deprotonation state of the

  13. Absorptive products

    International Nuclear Information System (INIS)

    Assarsson, P.G.; King, P.A.

    1976-01-01

    Applications for hydrophile gels produced by the radiation induced cross-linking in aqueous solution of polyethylene oxide and starch, as described in Norwegian patent 133501 (INIS RN 281494), such as sanitary napkins (diapers) and sanitary towels, are discussed. The process itself is also discussed and results, expressed as the percentage of insoluble gel and its absorptive capacity for saline solution as functions of the ratio of polyethylene oxide to starch and the radiation dose, are presented. (JIW)

  14. Electronic structure study of Co doped CeO2 nanoparticles using X-ray absorption fine structure spectroscopy

    International Nuclear Information System (INIS)

    Kumar, Shalendra; Gautam, Sanjeev; Song, T.K.; Chae, Keun Hwa; Jang, K.W.; Kim, S.S.

    2014-01-01

    Highlights: • The electronic structural of Co–CeO 2 nanoparticles is investigated using XAFS. • Ce M 5,4 , Ce L 3 and O K edge NEXAFS reveal that the Ce-ions are in +4 valence state. • The NEXAFS spectrum performed at Co L3,2-edge confirms Co-ion in 2+ state. • The EXAFS analysis also show that Co ions are occupying Ce position in doped CeO 2 . • The distances between Ce–O and Ce–Ce/Co in all shells decreases with Co doping. - Abstract: We investigated the electronic structure of well characterized Co doped CeO 2 nanoparticles using X-ray absorption fine structure (XAFS) spectroscopy. Near edge X-ray absorption fine structure (NEXAFS) spectra at Ce M 5,4 , Ce L 3 and O K-edge conclude that the Ce-ions are in +4 valence state in pure as well as in Co doped CeO 2 nanoparticles. The local structure around Ce-atom in Co doped CeO 2 nanoparticles was also determined using extended X-ray absorption fine structure (EXAFS) spectroscopy at Ce L 3 edge. The EXAFS analysis suggest that the inter-atomic distance of Ce–O, Ce–Ce/Co decreases with Co doping, which indicate a contraction of the lattice. The decease in Ce–O distance also reflect that there is a formation of oxygen vacancies in CeO 2 matrix. The Debye–Waller factor also shows the consistent behaviour for all the coordination shells. The atomic multiplet calculations for Co L 3,2 -edge was performed to determine the valence state, symmetry and field splitting, which reflect that Co-ions are in 2+ state and substituted at Ce-site with crystal field splitting of 10Dq=-0.57eV. The XAFS measurements reveal that the Co-ions occupy the Ce position in the CeO 2 host matrix and create a oxygen vacancy

  15. Infrared reflection absorption spectroscopy study of radiation-heterogeneous processes in the system of aluminum-hexane

    International Nuclear Information System (INIS)

    Gadzhieva, N.N.; Rimikhanova, A.N.; Garibov, A.A.

    2004-01-01

    Full text: Infrared reflection absorption spectroscopy (IRRAS) was applied to study the regularities of radiation conversion of hexane on the surface of aluminum. The research object was the thin polished aluminum plate by mark of AD-00 with reflection coefficient R=0.8†0.85 in infrared range λ=2.2†15 μ . As adsorbate unsaturated vapors of spectroscopy clear hexane were used. The absorption of hexane (C 2 H 14 ) was being studied manometric at pressures P=(0.1†1.0)·10 2 Pa , what corresponded to monolayer value of 1-10. The samples were irradiated with γ-quanta of 60 Co with D=1.03 Gy·s -1 doze rate. Infrared reflection spectrum when linear-polarized radiation fall on the sample under angle ψ=10 o was measured by spectrophotometer 'Specord 71 JR' in diapason of 4000-650cm -1 at the temperature by mean of special reflecting arrangements. Formation of molecular hydrogen (H 2 ) and other gaseous products of decomposition were controlled by chromotographical and infrared spectroscopical methods. The analysis of hexane infrared absorption spectra after radiation-stimulated adsorption on the surface of aluminum, points out the formation of H-bonded hydrocarbon complex ( ν∼2680cm -1 ) with much loosening of C-H bond (the molecular form of absorption) and the possibility of proceeding dissociative absorption with formation of metal-alkyls (ν∼2880, 2920, 2970 cm -1 ). Probability of the last mentioned process, which proceeds in the most defective centers, increases with increasing of γ-radiation doze. It was established that the radiation processes in hetero system Al-ads.C 6 H 14 accelerate the radiolysis of hexane. At all these the radiation decomposition of hexane in hetero system Al-ads.C 6 H 14 is accompanied by formation the surface hydrides (ν∼1700-2000 cm -1 ), acetylene (ν∼3200-3300 cm -1 ), ethylene (ν∼980 cm -1 ), and also gaseous products of molecular hydrogen decomposition (H 2 ) and hydrocarbons C 1 -C 5 (bands with maxima 770, 790

  16. Revisiting Absorptive Capacity

    DEFF Research Database (Denmark)

    de Araújo, Ana Luiza Lara; Ulhøi, John Parm; Lettl, Christopher

    Absorptive capacity has mostly been perceived as a 'passive' outcome of R&D investments. Recently, however, a growing interest into its 'proactive' potentials has emerged. This paper taps into this development and proposes a dynamic model for conceptualizing the determinants of the complementary...... learning processes of absorptive capacity, which comprise combinative and adaptive capabilities. Drawing on survey data (n=169), the study concludes that combinative capabilities primarily enhance transformative and exploratory learning processes, while adaptive capabilities strengthen all three learning...

  17. Theoretical study on the sound absorption of electrolytic solutions. I. Theoretical formulation

    Science.gov (United States)

    Yamaguchi, T.; Matsuoka, T.; Koda, S.

    2007-04-01

    A theory is formulated that describes the sound absorption of electrolytic solutions due to the relative motion of ions, including the formation of ion pairs. The theory is based on the Kubo-Green formula for the bulk viscosity. The time correlation function of the pressure is projected onto the bilinear product of the density modes of ions. The time development of the product of density modes is described by the diffusive limit of the generalized Langevin equation, and approximate expressions for the three- and four-body correlation functions required are given with the hypernetted-chain integral equation theory. Calculations on the aqueous solutions of model electrolytes are performed. It is demonstrated that the theory describes both the activated barrier crossing between contact and solvent-separated ion pairs and the Coulombic correlation between ions.

  18. Study of phosphorus absorption by eucalypt and rice using the 32P isotope

    International Nuclear Information System (INIS)

    Luca, Edgar Fernando de; Boaretto, Antonio Enedi; Muraoka, Takashi; Chitolina, Jose Carlos

    2000-01-01

    An experiment was carried out in greenhouse conditions with the objective of compare the different concepts of 'nutritional efficiency' and to test the hypothesis that the eucalypt is more efficient than the rice in absorbing the phosphorus of sources few soluble ones synthesised, being used the isotopic tracer technique. It was ended that the nutritional efficiency is relative, because the rice was more efficient than the eucalypt in absorbing the phosphorus of few soluble sources, but the eucalypt had larger biological use of the phosphorus. X-ray diffractometry and thermal differential analyses proved that the laboratory procedures allowed, in fact, to obtain the compositions Ca(H 2 32 PO 4 ).H 2 O, CaH 32 PO 4 .2H 2 O and Ca 3 ( 32 PO 4 ) 2 . The 'difference' method (conventional), employee to determine P recovery by plants, underestimated the absorption of this nutrient from eucalypt and rice cultures in relation to the isotopic method. (author)

  19. Studies of the X-ray absorption spectra of some methylcyano esters

    International Nuclear Information System (INIS)

    Takahashi, Osamu; Saito, Ko; Mitani, Masaki; Yoshida, Hiroaki; Tahara, Fumitaka; Sunami, Tetsuji; Waki, Keiichiro; Senba, Yasunori; Hiraya, Atsunari; Pettersson, Lars G.M.

    2005-01-01

    Density functional theory (DFT) has been applied to simulate core-excited photoabsorption spectra for some methylcyano esters within a transition potential (TP) framework. Our calculations for methylcyano formate at the N and O K-edges are consistent with previous experimental spectra. For methylcyano acetate the photoabsorption spectra at the N and O K-edges were reinvestigated experimentally. Contrary to the previous experiment, only one main peak was observed at the N K-edge and this peak was assigned to N(1s) ->π* excitation. This result was supported by our theoretical calculations. The general trends in the X-ray absorption spectra and the site-specific bond scission of methylcyano esters at the N and O K-edges are also discussed

  20. Studies on solvatochromic behavior of some monoazo derivatives using electronic absorption spectra

    Energy Technology Data Exchange (ETDEWEB)

    Sidir, Isa; Tasal, Erol; Guelseven, Yadigar [Department of Physics, Faculty of Arts and Sciences, Eskisehir Osmangazi University, 26480 Eskisehir (Turkey); Guengoer, Tayyar [Department of Physics, Faculty of Arts and Sciences, Akdeniz University, Antalya (Turkey); Berber, Halil [Department of Chemistry, Faculty of Sciences, Anadolu University, Eskisehir (Turkey); Oegretir, Cemil [Department of Chemistry, Faculty of Arts and Sciences, Eskisehir Osmangazi University, Eskisehir (Turkey)

    2009-06-15

    The electronic absorption spectra of 2',4'-dihydroxy-2-methoxyazobenzene and 4,2',4'-trihydroxyazobenzene molecules have been investigated in solvents with different polarities. The solvent dependent UV-vis spectral shifts, {nu}{sub max}, were analysed using some physical parameters such as refractive index, dielectric constant, Kamlet-Taft parameters, {alpha} (hydrogen bond donating ability) and {beta} (hydrogen bond accepting ability). The electronic transitions are assigned and the solvent induced spectral shifts have been analysed in relation to different solute-solvent interaction mechanisms using linear regression analysis. The results of fitting coefficients obtained from the analysis helped us to estimate the contribution of each type of interaction to the spectral shift in the molecule under consideration. It is concluded that the electronic character of the chemical nature of the solvent and the electronic character of substituents are the important factor for the observed solvatochromism. (author)

  1. Experimental study of neutron-optical potential with absorption using Fabry-Perot magnetic resonator

    International Nuclear Information System (INIS)

    Hino, M.; Tasaki, S.; Ebisawa, T.; Kawai, T.; Achiwa, N.; Yamazaki, D.

    1999-01-01

    Complete text of publication follows. Recently spin precession angles of neutrons tunneling and non-tunneling through [Permalloy45(PA)-germanium(Ge)]-PA Fabry-Perot magnetic resonator have been observed [1]. The spin precession angle is well reproduced by the theoretical phase difference of up and down spin neutron wave function based on one-dimensional Schroedinger equation using optical potential model [2]. Spin precession angle and transmission probability of neutron through PA-(Ge/Gd)-PA Fabry-Perot magnetic resonator are presented, where the gap(Ge/Gd) layer consists of germanium and gadolinium atoms, and the optical potential model for magnetic multilayer system with absorption is discussed. (author) [1] M. Hino, et al., Physica B 241-243, 1083 (1998).; [2] S. Yamada, et al., Annu. Rep. Res. Reactor Inst. Kyoto Univ. 11, 8 (1978)

  2. Numerical study on design for wave energy generation of a floater for energy absorption

    International Nuclear Information System (INIS)

    Li, Kui Ming; Parthasarathy, Nanjundan; Choi, Yoon Hwan; Lee, Yeon Won

    2012-01-01

    In order to design a wave energy generating system of a floater type, a 6 DOF motion technique was applied to the three Dimensional CFD analysis on a floating body and the behavior was interpreted according to the nature of the incoming waves. Waves in a tank model were generated using a single floater comparing with that of a Pelamis wave energy converter. In this paper, we focus on four variables, namely the wave height, angular velocity, diameter and length of the floater. The process was carried out in three stages and it was found that there are energy absorption differences in different parameters of wave height, length and the diameter of a floater during simulation, thus leading for the necessity of an optimal design for wave energy generation

  3. Comparative study of irreversibilities in an aqua-ammonia absorption refrigeration system

    Energy Technology Data Exchange (ETDEWEB)

    Ataer, O E [Gazi Univ., Ankara (TR). Mechanical Engineering Dept.; Gogus, Y [Middle East Technical Univ., Ankara (Turkey)

    1991-03-01

    Irreversibilities in components of an aqua-ammonia absorption refrigeration system (ARS) have been determined by second law analysis. The components of the ARS are as follows: condenser, evaporator, absorber, generator, pump, expansion valves, mixture heat exchanger and refrigerant heat exchanger. It is assumed that the ammonia concentration at the generator exit is, independent of the other parameters, equal to 0.999 and at the evaporator exit the gas is saturated vapour. Pressure losses between the generator and condenser, and the evaporator and absorber are taken into consideration. In the results the dimensionless exergy loss of each component, the exergetic coefficient of performance, the coefficient of performance and the circulation ratio are given graphically for each different generator, evaporator, condenser and absorber temperature. (author).

  4. Attenuation studies near K-absorption edges using Compton scattered 241Am gamma rays

    International Nuclear Information System (INIS)

    Abdullah, K.K.; Ramachandran, N.; Karunakaran Nair, K.; Babu, B.R.S.; Joseph, Antony; Thomas, Rajive; Varier, K.M.

    2008-01-01

    We have carried out photon attenuation measurements at several energies in the range from 49.38 keV to 57.96 keV around the K-absorption edges of the rare earth elements Sm, Eu, Gd, Tb, Dy and Er using 59.54 keV gamma rays from 241 Am source after Compton scattering from an aluminium target. Pellets of oxides of the rare earth elements were chosen as mixture absorbers in these investigations. A narrow beam good geometry set-up was used for the attenuation measurements. The scattered gamma rays were detected by an HPGe detector. The results are consistent with theoretical values derived from the XCOM package. (author)

  5. Gamma-ray energy absorption and exposure buildup factor studies in some human tissues with endometriosis

    Energy Technology Data Exchange (ETDEWEB)

    Kurudirek, Murat, E-mail: mkurudirek@gmail.co [Faculty of Science, Department of Physics, Ataturk University, 25240 Erzurum (Turkey); Dogan, Bekir [Faculty of Science, Department of Physics, Ataturk University, 25240 Erzurum (Turkey); Ingec, Metin [Faculty of Medicine, Department of Obstetrics and Gynecology, Ataturk University, 25240 Erzurum (Turkey); Ekinci, Neslihan; Ozdemir, Yueksel [Faculty of Science, Department of Physics, Ataturk University, 25240 Erzurum (Turkey)

    2011-02-15

    Human tissues with endometriosis have been analyzed in terms of energy absorption (EABF) and exposure (EBF) buildup factors using the five-parameter geometric progression (G-P) fitting formula in the energy region 0.015-15 MeV up to a penetration depth of 40 mfp (mean free path). Chemical compositions of the tissue samples were determined using a wavelength dispersive X-ray fluorescence spectrometer (WDXRFS). Possible conclusions were drawn due to significant variations in EABF and EBF for the selected tissues when photon energy, penetration depth and chemical composition changed. Buildup factors so obtained may be of use when the method of choice for treatment of endometriosis is radiotherapy.

  6. Absorption column working study for iodine formed in spent fuel reprocessing plant gaseous effluents: hydrodynamic and mass transfer

    International Nuclear Information System (INIS)

    Vignau, B.

    1986-09-01

    The hydrodynamic and matter transfer parameters has been studied on absorption columns destined to trap iodine issued of spent fuel reprocessing plants. These columns have different packing - Raschig rings (glass, ceramic, PVC, steel) - Berl saddles (ceramic) - Weaved metallic thread (steel). The effect of dimension and of packing structure on gas pressure drop and on liquid holdup has been evaluated. The partial transfer coefficients of I 2 -Air-NaOH system has been the object of an experimental study. This system can be simulated by CO 2 -Air-NaOH system [fr

  7. Inhibition by natural dietary substances of gastrointestinal absorption of starch and sucrose in rats and pigs: 1. Acute studies.

    Science.gov (United States)

    Preuss, Harry G; Echard, Bobby; Bagchi, Debasis; Stohs, Sidney

    2007-08-06

    Rapid gastrointestinal absorption of refined carbohydrates (CHO) is linked to perturbed glucose-insulin metabolism that is, in turn, associated with many chronic health disorders. We assessed the ability of various natural substances, commonly referred to as "CHO blockers," to influence starch and sucrose absorption in vivo in ninety-six rats and two pigs. These natural enzyme inhibitors of amylase/sucrase reportedly lessen breakdown of starches and sucrose in the gastrointestinal tract, limiting their absorption. To estimate absorption, groups of nine SD rats were gavaged with water or water plus rice starch and/or sucrose; and circulating glucose was measured at timed intervals thereafter. For each variation in the protocol a total of at least nine different rats were studied with an equal number of internal controls on three different occasions. The pigs rapidly drank CHO and inhibitors in their drinking water. In rats, glucose elevations above baseline over four hours following rice starch challenge as estimated by area-under-curve (AUC) were 40%, 27%, and 85% of their internal control after ingesting bean extract, hibiscus extract, and l-arabinose respectively in addition to the rice starch. The former two were significantly different from control. L-Arabinose virtually eliminated the rising circulating glucose levels after sucrose challenge, whereas hibiscus and bean extracts were associated with lesser decreases than l-arabinose that were still significantly lower than control. The glucose elevations above baseline over four hours in rats receiving sucrose (AUC) were 51%, 43% and 2% of control for bean extract, hibiscus extract, and L-arabinose, respectively. Evidence for dose-response of bean and hibiscus extracts is reported. Giving the natural substances minus CHO challenge caused no significant changes in circulating glucose concentrations, indicating no major effects on overall metabolism. A formula combining these natural products significantly

  8. Photoacoustic and filter measurements related to aerosol light absorption during the Northern Front Range Air Quality Study (Colorado 1996/1997)

    Science.gov (United States)

    Moosmüller, H.; Arnott, W. P.; Rogers, C. F.; Chow, J. C.; Frazier, C. A.; Sherman, L. E.; Dietrich, D. L.

    1998-11-01

    A new photoacoustic instrument for the measurement of aerosol light absorption was collocated with conventional aerosol instrumentation during the 1996-1997 winter intensive monitoring period of the Northern Front Range Air Quality Study. Measurements of the light absorption efficiency for black carbon were 5 m2/g at 685 nm and 10 m2/g at 532 nm, and for elemental carbon, they were 3.6 m2/g at 685 nm. We show that these values together with previous photoacoustic measurements of aerosol light absorption shed some light on the wavelength dependence of absorption efficiency for carbonaceous aerosol in the visible and near-visible region. Integrating plate type filter measurements of aerosol light absorption result in far larger values than those measured with the photoacoustic instrument. We demonstrate that a recently published correction technique [Horvath, 1997] can yield improved agreement.

  9. Critical study of absorption tests based on the measurement of breath 14CO2 after administration of 14C-labelled fats

    International Nuclear Information System (INIS)

    Grenier, J.F.; Dauchel, J.; Eloy, M.R.; Mendel, C.; Privat, J.P.

    1976-01-01

    Oral administration of 14 C-labelled triolein is a useful technique for studying absorption of fats if faecal excretion of the label is observed. However, the difficulties of complete collection and reliable assay of faeces discourage use of this technique, and suggestions have been made that quantitation of absorption by assay of 14 CO 2 exhalation rate might be simpler and adequately reliable. We have compared in 25 subjects the exhalation of 14 CO 2 with the blood activity levels and with the faecal excretion of unabsorbed fat. Our results indicate that the exhalation rate of 14 CO 2 is so poorly correlated with the other indices of absorption that the amount of 14 CO 2 exhaled is not a useful measure of 14 C-triolein absorption. This fact is presumably explained by the variability in the rate of metabolism of absorbed fat, a process that intervenes between absorption and exhalation. (author)

  10. PIXE study on absorption of arsenate and arsenite by arsenic hyperaccumulating fern (Pteris vittata)

    International Nuclear Information System (INIS)

    Yamazaki, H.; Ishii, K.; Matsuyama, S.

    2008-01-01

    Pytoremediation using an arsenic hyperaccumulator, Petris vittata L., has generated an increasing interest worldwide due to both environmentally sound and cost effectiveness. However the mechanism of arsenic accumulation by this fern is not clear at this time. This study examined the uptake of arsenate (As(V)) and arsenite (As(III)) by a hydroponic culture of Pteris vittata using both in-air submilli-PIXE for different parts of the fern and in-air micro-PIXE for the tissue cells. These PIXE analysis systems used 3 MeV proton beams from a 4.5-MV single-ended Dynamitron accelerator at Tohoku University, Japan. The fern took up both arsenate and arsenite from hydroponic solutions which were spiked with 50 mg of arsenic per litter. Final amount of arsenic accumulation in the fern is 1,500 mg per kg (wet weight) of the plant biomass in arsenite treatment and 1,100 mg per kg in arsenate treatment. Arsenic accumulation was not observed at the root parts of the ferns. The in-vivo mapping of elements by submilli-PIXE analyses on the fern laminas showed the arsenic accumulation in the edges of a pinna. The micro-PIXE analyses revealed arsenic maps homogeneously distributed in cells of the lamina, stem and rhizome of the fern. These results indicate that arsenic, both arsenate and arsenite in a contaminated medium are translocated quickly from roots to fronds of Pteris vittata, and distributes homogeneously into tissue cells of the fern laminas. (author)

  11. X-ray absorption spectroscopy study of the LixFePO4 cathode during cycling using a novel electrochemical in situ reaction cell

    International Nuclear Information System (INIS)

    Deb, A.; Bergmann, U.; Cairns, E.L.; California Univ., Berkeley, CA; Cramer, S.P.; California Univ., Davis, CA

    2004-01-01

    The extraction and insertion of lithium in LiFePO 4 has been investigated in practical Li-ion intercalation electrodes for Li-ion batteries using Fe K-edge X-ray absorption spectroscopy (XAS). A versatile electrochemical in situ reaction cell was utilized, specifically designed for long-term X-ray experiments on battery electrodes during the lithium-extraction/insertion process in electrode materials for Li-ion batteries. The electrode contained about 7.7 mg of LiFePO 4 on a 20 μm-thick Al foil. In order to determine the charge compensation mechanism and structural perturbations occurring in the system during cycling, in situ X-ray absorption fine-structure spectroscopy (XAFS) measurements were conducted on the cell at a moderate rate using typical Li-ion battery operating voltages (3.0-4.1 V versus Li/Li + ).XAS studies of the LiFePO 4 electrode measured at the initial state (LiFePO 4 ) showed iron to be in the Fe(II) state corresponding to the initial state (0.0 mAh) of the battery, whereas in the delithiated state (FePO 4 ) iron was found to be in the FE(III) state corresponding to the final charged state (3 m Ah) of the battery. The X-ray absorption near-edge structure (XANES) region of the XAS spectra revealed a high-spin configuration for the two states [Fe(II), d 6 and Fe(III), d 5 ]. The XAFS data analysis confirmed that the olivine structure of the LeFePO 4 and FePO 4 is retained by the electrodes, which is in agreement with the X-ray diffraction observations on these compounds. The XAFS data that were collected continuously during cycling revealed details about the response of the cathode to Li insertion and extraction. These measurements on the LiFePO 4 cathode show that the material retains good structural short-range order leading to superior cycling

  12. An Empirical Investigation into a Subsidiary Absorptive Capacity Process Model

    DEFF Research Database (Denmark)

    Schleimer, Stephanie; Pedersen, Torben

    2011-01-01

    and empirically test a process model of absorptive capacity. The setting of our empirical study is 213 subsidiaries of multinational enterprises and the focus is on the capacity of these subsidiaries to successfully absorb best practices in marketing strategy from their headquarters. This setting allows us...... to explore the process model in its entirety, including different drivers of subsidiary absorptive capacity (organizational mechanisms and contextual drivers), the three original dimensions of absorptive capacity (recognition, assimilation, application), and related outcomes (implementation...... and internalization of the best practice). The study’s findings reveal that managers have discretion in promoting absorptive capacity through the application of specific organizational mechanism and that the impact of contextual drivers on subsidiary absorptive capacity is not direct, but mediated...

  13. EPR and optical absorption study of Cu{sup 2+} doped lithium sulphate monohydrate (LSMH) single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Sheela, K. Juliet; Subramanian, P., E-mail: psubramaniangri@gmail.com [Department of Physics, Gandhigram Rural Institute-Deemed University, Gandhigram, Dindigul-624302, Tamilnadu (India); Krishnan, S. Radha; Shanmugam, V. M. [CSIR-Central Electrochemical Research Institute, Karaikudi-63006, Tamilnadu (India)

    2016-05-23

    EPR study of Cu{sup 2+} doped NLO active Lithium Sulphate monohydrate (Li{sub 2}SO{sub 4.}H{sub 2}O) single crystals were grown successfully by slow evaporation method at room temperature. The principal values of g and A tensors indicate existence of orthorhombic symmetry around the Cu{sup 2+} ion. From the direction cosines of g and A tensors, the locations of Cu{sup 2+} in the lattice have been identified as interstitial site. Optical absorption confirms the rhombic symmetry and ground state wave function of the Cu{sup 2+} ion in a lattice as d{sub x2-y2}.

  14. Study of X-ray L2 absorption edges of Gd, Dy, Ho and Er in metals and compounds

    International Nuclear Information System (INIS)

    Agarwal, B.K.; Agarwal, B.R.K.

    1978-01-01

    The positions and shapes of L2 X-ray absorption edges of Gd, Dy, Ho and Er have been studied in metals and in oxides and chlorides, using a forty centimetre bent mica crystal spectrograph. It has been found that the L2 edge shifts towards the high energy side in the compounds and that the chemical shift ΔE depends on the degree of covalency involved. The white line structure at the edge has been analysed in terms of transitions of L2 shell electron to optical nd (n >= 5) states. (author)

  15. A cell for extended x-ray absorption fine structure studies of oxygen sensitive products of redox reactions

    International Nuclear Information System (INIS)

    Furenlid, L.R.; Renner, M.W.; Fajer, J.

    1990-01-01

    We describe a cell suitable for extended x-ray absorption fine structure (EXAFS) studies of oxygen and/or water sensitive products of redox reactions. The cell utilizes aluminized Mylar windows that are transparent to x rays, provide low gas permeability, and allow vacuum to be maintained in the cell. The windows are attached to the glassware with an epoxy that resists attack by common organic solvents. Additional side arms allow multiple spectroscopic probes of the same sample under anaerobic and anhydrous conditions

  16. [sup 205]Bi/[sup 206]Bi cyclotron production from Pb-isotopes for absorption studies in humans

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, R.; Dresow, B.; Heinrich, H.C. (Universitaetskrankenhaus Eppendorf, Hamburg (Germany). Abt. Medizinische Biochemie); Wendel, J.; Bechtold, V. (Kernforschungszentrum Karlsruhe GmbH (Germany). Inst. fuer Kernphysik)

    1993-12-01

    Pb(p,xn) thick target excitation functions were measured in the energy range 10-38 MeV in order to optimize the production of isotopically pure radiobismuth from [sup nat]Pb, [sup 206]Pb, and [sup 207]Pb. Additionally, the decay of Po-isotopes from deuteron irradiation of natural bismuth ([sup 209]Bi) was exploited for radiobismuth production. [sup 205]Bi was produced from [sup 206]Pb at 20 MeV with only 2% of [sup 206]Bi at 4 weeks post irradiation. Bismuth compounds as used in the treatment of peptic ulcer were labeled with [sup 205]Bi for absorption studies in animals and subjects. (Author).

  17. A reaction cell with sample laser heating for in situ soft X-ray absorption spectroscopy studies under environmental conditions.

    Science.gov (United States)

    Escudero, Carlos; Jiang, Peng; Pach, Elzbieta; Borondics, Ferenc; West, Mark W; Tuxen, Anders; Chintapalli, Mahati; Carenco, Sophie; Guo, Jinghua; Salmeron, Miquel

    2013-05-01

    A miniature (1 ml volume) reaction cell with transparent X-ray windows and laser heating of the sample has been designed to conduct X-ray absorption spectroscopy studies of materials in the presence of gases at atmospheric pressures. Heating by laser solves the problems associated with the presence of reactive gases interacting with hot filaments used in resistive heating methods. It also facilitates collection of a small total electron yield signal by eliminating interference with heating current leakage and ground loops. The excellent operation of the cell is demonstrated with examples of CO and H2 Fischer-Tropsch reactions on Co nanoparticles.

  18. Effect of incident beam and diffuse radiation on par absorption, photosynthesis and transpiration of sitka spruce - a simulation study

    International Nuclear Information System (INIS)

    Wang, Y.P.; Jarvis, P.G.

    1990-01-01

    A simulation model, Maestro, is used to study the influence of beam fraction in the incident radiation and the radiance distribution of the sky diffuse radiation on PAR absorption, photosynthesis and transpiration of a Sitka spruce (Picea sitchensis (Bong.) Carr) tree crown. It is concluded that inaccurate separation of beam and diffuse radiation leads to significant errors in estimating the amounts of PAR absorbed, photosynthesis and transpiration by a tree in the stand. Much more attention should be paid to adequate descriptions of the radiance distribution of the sky diffuse radiation under different sky conditions. A useful approach is proposed for simulating the incident global radiaiton in a physiological, process-based model

  19. X-ray absorption spectroscopy and neutron diffraction study of the perovskite-type rare-earth cobaltites

    Science.gov (United States)

    Sikolenko, V.; Efimova, E.; Franz, A.; Ritter, C.; Troyanchuk, I. O.; Karpinsky, D.; Zubavichus, Y.; Veligzhanin, A.; Tiutiunnikov, S. I.; Sazonov, A.; Efimov, V.

    2018-05-01

    Correlations between local and long-range structure distortions in the perovskite-type RE1-xSrxCoO3-δ (RE = La, Pr, Nd; x = 0.0 and 0.5) compounds have been studied at room temperature by extended X-ray absorption fine structure (EXAFS) at the Co K-edge and high-resolution neutron powder diffraction (NPD). The use of two complementary experimental techniques allowed us to explore the influence of the type of rare-earth element and strontium substitution on unusual behavior of static and dynamic features of both the Co-O bond lengths.

  20. Numerical study for identification of influence of energy absorption and frontal crush for vehicle crashworthiness

    Science.gov (United States)

    Suman, Shwetabh; Shah, Haard; Susarla, Vaibhav; Ravi, K.

    2017-11-01

    According to the statistics it has been seen that everyday nearly 400 people are killed due to road accidents. Due to this it has become an important concern to concentrate on the safety of the passengers which can be done by improving the crashworthiness of the vehicle. During the impact, a large amount of energy is released which if not absorbed, will be transmitted to the passenger compartment. For the safety of the passenger this energy has to be absorbed. Front rail is one of the main energy absorbing components in the vehicle front structure. When it comes to the structure and material of the part or component of the vehicle that is to be designed for crash, it is done based on three parameters: Specific Energy of Absorption, Mass of the front rail and maximum crush force. In this work, we are considering different internal geometries with different materials to increase the energy absorbing capacity of the front rail. Based on the extensive analysis carried aluminium seizes to be the opt material for frontal crash.

  1. Organizational procedure for the study of pion production and absorption processes on nuclei

    International Nuclear Information System (INIS)

    Banerjee, M.K.; Walker, G.E.

    1983-01-01

    For nuclear processes involving pions, such as pion production/absorption or exchange currents, it is shown that a natural organization involves adoption of the πNN vertex function g/sub π/(q 2 )#betta# 5 tau/sub α/, where q is the pion four-momentum and g/sub π/(m/sub π/ 2 )approx. =13.4 is the renormalized pion-nucleon coupling constant. The result is independent of the form and details of any fundamental interaction Lagrangian. The difference between g/sub π/(q 2 )#betta# 5 tau/sub α/ and the fully-dressed πNN vertex function contributes to amplitudes involving more bosons, e.g., scattering amplitudes (πN→πN), production amplitudes (πN→ππN), etc. Such contributions are mediated through either seagull-like terms or P11 intermediate states. It is pointed out that it is neither necessary nor practical to calculate these partial contributions to scattering and production amplitudes. One can always exploit other approaches, theoretical and phenomenological, to make reasonably good models for the full amplitudes. The usual procedure of including the effects of negative energy parts of the nucleon propagator in interaction potentials, exchange currents, etc., is easily included in the present organization. The result is that from scattering amplitudes, etc; the positive energy nucleon poles are deleted but Z graphs are included

  2. Studies of the Effective Total and Resonance Absorption Cross Sections for Zircaloy 2 and Zirconium

    Energy Technology Data Exchange (ETDEWEB)

    Hellstrand, E; Lindahl, G; Lundgren, G

    1961-06-15

    Using pile oscillator technique, the total absorption cross section for zircaloy 2 plates has been determined in the neutron spectrum of the reactor R1. The plate thickness was varied in six steps from 0. 2 mm to 6. 4 mm. The thermal cross section for the alloy was calculated from cross section data and the known composition of the alloy. By subtracting this value from the measured cross sections and dividing by the factor {alpha}=2/{radical}({pi}) x r x {radical}(T/T{sub 0}) the effective resonance integrals were obtained. After subtraction of a constant amount for resonance contributions from hafnium, tin etc., effective resonance integrals for zirconium could be evaluated. An extrapolated value of 0.85 {+-} 0.15 b was obtained for the infinitely dilute integral (l/v part excluded). The ratio of the resonance integral at plate thicknesses 0.2 and 6.4 mm came out as 1.65 {+-} 0.25.

  3. X-ray absorption and Raman spectroscopy studies of molybdenum environments in borosilicate waste glasses

    Science.gov (United States)

    McKeown, David A.; Gan, Hao; Pegg, Ian L.

    2017-05-01

    Mo-containing high-level nuclear waste borosilicate glasses were investigated as part of an effort to improve Mo loading while avoiding yellow phase crystallization. Previous work showed that additions of vanadium decrease yellow phase formation and increases Mo solubility. X-ray absorption spectroscopy (XAS) and Raman spectroscopy were used to characterize Mo environments in HLW borosilicate glasses and to investigate possible structural relationships between Mo and V. Mo XAS spectra for the glasses indicate isolated tetrahedral Mo6+O4 with Mo-O distances near 1.75 Å. V XANES indicate tetrahedral V5+O4 as the dominant species. Raman spectra show composition dependent trends, where Mo-O symmetrical stretch mode frequencies (ν1) are sensitive to the mix of alkali and alkaline earth cations, decreasing by up to 10 cm-1 for glasses that change from Li+ to Na+ as the dominant network-modifying species. This indicates that MoO4 tetrahedra are isolated from the borosilicate network and are surrounded, at least partly, by Na+ and Li+. Secondary ν1 frequency effects, with changes up to 7 cm-1, were also observed with increasing V2O5 and MoO3 content. These secondary trends may indicate MoO4-MoO4 and MoO4-VO4 clustering, suggesting that V additions may stabilize Mo in the matrix with respect to yellow phase formation.

  4. Surface modification study of borate materials from B K-edge X-ray absorption spectroscopy

    Science.gov (United States)

    Kasrai, Masoud; Fleet, Michael E.; Muthupari, Swaminathan; Li, D.; Bancroft, G. M.

    The B K-edge X-ray absorption near-edge structure (XANES) spectra of two borates with tetrahedrally-coordinated B [[4]B; natural danburite (CaB2Si2O8) and synthetic boron phosphate (BPO4)] have been recorded in total electron yield (TEY) and fluorescence yield (FY) modes to investigate the surface and bulk structure of these materials. The TEY XANES measurement shows that danburite is susceptible to surface damage involving conversion of [4]B sites to [3]B sites by reaction with moisture and/or mechanical abrasion (grinding, polishing, etc.). The bulk of the mineral is essentially unaffected. Commercial boron phosphate powder exhibits more extensive surface and bulk damage, which increases with air exposure but is recovered on heating at 650°C. In contrast to ELNES, the XANES technique is not affected by beam damage and when collected in the FY mode is capable of yielding meaningful information on the coordination and intermediate-range structure of B in borate and borosilicate materials.

  5. Absorption process of a falling film on a tubular absorber: An experimental and numerical study

    Energy Technology Data Exchange (ETDEWEB)

    Islam, Md. Raisul [Department of Mechanical Engineering, Curtin University of Technology, Sarawak Campus Malaysia, CDT 250, 98009 Miri, Sarawak (Malaysia)

    2008-08-15

    This paper describes an experimental and theoretical analysis of the combined heat and mass transfer processes that take place in the absorber of vapor absorption cooling systems. The effect of the main operating variables such as solution inlet temperature, solution flow rate, coolant inlet temperature, coolant flow rate and absorber vapor pressure on the performance of absorber is experimentally investigated. A mathematical model that takes account of the geometrical details of the solution and coolant flow is developed following the traditional heat exchanger analysis to obtain additional information on the performance of the absorber. The governing equations are solved analytically using Laplace Transformation technique. The variations of the concentration of solution and the temperature of the coolant and solution after each horizontal tube are analyzed. There is satisfactory agreement between the predictions of the analytical model and the experimental results. The serpentine arrangement of the coolant flow in the absorber tubes results in a temperature and concentration variation of the solution mainly along the height of the absorber. (author)

  6. Experimental study on a project with CHP system basing on absorption cycles

    International Nuclear Information System (INIS)

    Sun, Jian; Fu, Lin; Sun, Fangtian; Zhang, Shigang

    2014-01-01

    A new heat recovery system for the CHP (combined heating and power) is presented, and HRU (heat recovery unit) and AHE (absorption heat exchanger) are invented to improve the total energy efficiency of the conventional CHP system by more than 20%, which are installed at the thermal power plant and the heating substation separately. The HRU could recover the low grade heat of exhausted steam from the turbine directly, and the AHE could decrease the temperature of back water of primary pipe to a lower temperature than that of secondary pipe without changing the flow rate of secondary pipe. A large demonstration project employing this technology has been built in Datong of China. And experimental results of HRU and AHE are presented to evaluate this system. - Highlights: • The total energy efficiency of CHP could by increased by more than 20%. • Temperature of back water of primary pipe could be lower than that of secondary pipe. • Heating capacity of primary pipe could be increased significantly. • Low grade heat of exhausted steam from turbine could be recovered directly

  7. Experimental and theoretical studies of the VUV emission and absorption spectra of H2, HD and D2 molecules

    International Nuclear Information System (INIS)

    Roudjane, M.

    2007-12-01

    The aim of this thesis is to carry out an experimental study of the absorption and emission spectra of the D 2 and HD isotopes, with high resolution, in the VUV domain and to supplement it by a theoretical study of the excited electronic states involved in the observed transitions. The emission spectra of HD and D 2 are produced by Penning discharge source operating under low pressure and are recorded in the spectral range 78 - 170 nm. The recorded spectra contains more than 20.000 lines. The analysis of the spectrum consists in identifying and assigning the lines to the electronic transitions between energy levels of the molecule. The present analysis is based on our theoretical calculations of the ro-vibrational energy levels of the excited electronic states and the transition probabilities from these states towards the energy levels of the fundamental state. The theoretical results are obtained by resolving the coupled equations between the excited electronic states B 1 Σ u 1 , B' 1 Σ u 1 , C 1 Π u 1 and D 1 Π u 1 , taking into account the nonadiabatic couplings between these states, and they are obtained in the adiabatic approximation for the excited electronic states B''B-bar 1 Σ u + , D' 1 Π u 1 and D'' 1 Π u 1 . The equations are resolved using a modern method based on the discretization variables representation method. In addition, we have carried out a study of the absorption spectra of the HD and D 2 molecules

  8. Serum-ferritin and iron absorption for the study of body iron stored in the Thai population

    International Nuclear Information System (INIS)

    Plehachinda, R.

    1984-05-01

    Measurements of serum ferritin by an ''in-house'' immunoradiometric assay (IRMA) method were used in conjunction with estimations of gastro-intestinal iron absorption from a standard test dose of ferrous ascorbate, measurements of blood haemoglobin and measurements of other haematological parameters to study body iron status in various population groups and to assess changes in body iron status after food-iron fortification. The IRMA method particularly covered the lower range of serum ferritin levels from 0.5 to 10 μg/litre, corresponding to iron deficiency. Quality control indicated satisfactory assay performance. In preliminary studies, serum ferritin level was found to be well correlated with gastro-intestinal iron absorption as an indicator of body iron status. Normal adult male subjects in Bangkok showed levels of 21-314 μg/litre and normal adult female levels of 13-173 μg/litre, in general agreement with values reported by other authors. Measurements were then extended to subjects in an area of north-eastern Thailand where iron-deficiency was common, to assess the effectiveness of food-iron fortification programmes. Measurements were also made on male blood donors in Bangkok, pregnant female subjects in Bangkok and north-eastern Thailand, school children in an area of southern Thailand where hookworm infestation was common and schoolchildren and adult female subjects in an area of northern Thailand where goitre was endemic. The results of all these studies are presented

  9. Structure of bimetallic clusters. Extended x-ray absorption fine structure (EXAFS) studies of Rh--Cu clusters

    International Nuclear Information System (INIS)

    Meitzner, G.; Via, G.H.; Lytle, F.W.; Sinfelt, J.H.

    1983-01-01

    An investigation of the structure of the bimetallic clusters present in rhodium--copper catalysts was conducted with the use of extended x-ray absorption fine structure (EXAFS) measurements. Two catalysts were studied, both employing silica as a support for the clusters and both containing 1 wt. % rhodium. In one catalyst the Cu:Rh atomic ratio was 1:2 and in the other 1:1. Studies were made of the EXAFS associated with the K absorption edges of the rhodium and copper. The results of the EXAFS studies indicate that copper concentrates at the surface of the rhodium--copper clusters. In this regard the results are similar to our earlier reported results on ruthenium--copper clusters. However, the extent of surface segregation of the copper appears to be less pronounced for rhodium--copper clusters. This result is reasonable on the basis that rhodium and copper, unlike ruthenium and copper, exhibit at least some miscibility in the bulk

  10. Excited-state dynamics of a ruthenium(II) catalyst studied by transient photofragmentation in gas phase and transient absorption in solution

    Energy Technology Data Exchange (ETDEWEB)

    Imanbaew, D.; Nosenko, Y. [Fachbereich Chemie, Technische Universität Kaiserslautern, Erwin-Schrödinger-Str. 52–54, 67663 Kaiserslautern (Germany); Forschungszentrum OPTIMAS, Erwin-Schrödinger-Str. 46, 67663 Kaiserslautern (Germany); Kerner, C. [Fachbereich Chemie, Technische Universität Kaiserslautern, Erwin-Schrödinger-Str. 52–54, 67663 Kaiserslautern (Germany); Chevalier, K.; Rupp, F. [Fachbereich Physik, Technische Universität Kaiserslautern, Erwin-Schrödinger-Str. 46, 67663 Kaiserslautern (Germany); Riehn, C., E-mail: riehn@chemie.uni-kl.de [Fachbereich Chemie, Technische Universität Kaiserslautern, Erwin-Schrödinger-Str. 52–54, 67663 Kaiserslautern (Germany); Forschungszentrum OPTIMAS, Erwin-Schrödinger-Str. 46, 67663 Kaiserslautern (Germany); Thiel, W.R. [Fachbereich Chemie, Technische Universität Kaiserslautern, Erwin-Schrödinger-Str. 52–54, 67663 Kaiserslautern (Germany); Diller, R. [Fachbereich Physik, Technische Universität Kaiserslautern, Erwin-Schrödinger-Str. 46, 67663 Kaiserslautern (Germany)

    2014-10-17

    Graphical abstract: - Highlights: • Ultrafast dynamics of new Ru(II) catalysts investigated in gas phase and solution. • Catalyst activation (HCl loss) achieved in ion trap by UV photoexcitation. • Electronic relaxation proceeds by IVR and IC followed by ground state dissociation. • No triplet formation in contrast to other Ru-polypyridine complexes. • Solvent prohibits catalyst activation in solution by fast vibrational cooling. - Abstract: We report studies on the excited state dynamics of new ruthenium(II) complexes [(η{sup 6}-cymene)RuCl(apypm)]PF{sub 6} (apypm=2-NR{sub 2}-4-(pyridine-2-yl)-pyrimidine, R=CH{sub 3} (1)/H (2)) which, in their active form [1{sup +}-HCl] and [2{sup +}-HCl], catalyze the transfer hydrogenation of arylalkyl ketones in the absence of a base. The investigations encompass femtosecond pump–probe transient mass spectrometry under isolated conditions and transient absorption spectroscopy in acetonitrile solution, both on the cations [(η{sup 6}-cymene)RuCl(apypm)]{sup +} (1{sup +}, 2{sup +}). Gas phase studies on mass selected ions were performed in an ESI ion trap mass spectrometer by transient photofragmentation, unambiguously proving the formation of the activated catalyst species [1{sup +}-HCl] or [2{sup +}-HCl] after photoexcitation being the only fragmentation channel. The primary excited state dynamics in the gas phase could be fitted to a biexponential decay, yielding time constants of <100 fs and 1–3 ps. Transient absorption spectroscopy performed in acetonitrile solution using femtosecond UV/Vis and IR probe laser pulses revealed additional deactivation processes on longer time scales (∼7–12 ps). However, the formation of the active catalyst species after photoexcitation could not be observed in solution. The results from both studies are compared to former CID investigations and DFT calculations concerning the activation mechanism.

  11. The absorption of lactic acid is more synchronized with the absorption of glucose than with the absorption of short-chain fatty acids - A study with sows fed diets varying in dietary fibre

    DEFF Research Database (Denmark)

    Serena, Anja; Bach Knudsen, Knud Erik; Jørgensen, Henry

    2007-01-01

    Sows were fed one of three diets varying in level and type of dietary fibre (DF). A low DF diet (LF; 17% DF) based on wheat and barley and two generic high DF diets (HF1, high in soluble DF and HF2, high in insoluble DF; approx. 41% DF) where the cereals were substituted with co-products (sugar....../d of the three experimental diets in a repeated 3 × 3 crossover design. Blood samples were collected the last day in each period at - 120, - 60, 0, 15, 30, 45, 60, 90, 120 and then at 60-min intervals up to 600 min after feeding. Although lactic acid (LA) is formed by microbial fermentation, the absorption...

  12. 14C-Methylenebisphenylisocyanate (14C-MDI). Study of absorption after single dermal and intradermal administration in rats

    International Nuclear Information System (INIS)

    Leibold, E.; Hoffmann, H.D.; Hildebrand, B.

    1999-01-01

    The absorption, distribution and excretion of radioactivity was studied in groups of four male Wistar rats following a single dermal and intradermal administration of 14 C- Methylenebisphenylisocyanate ( 14 C-MDI) at nominal dose levels of 4.0 and 0.4 mg/cm 2 for dermal administration and 0.4 mg/animal for intradermal administration. These dose levels nominally corresponded to 40 and 4.0 mg/animal for dermal administration. Considering the animal weights, dose levels corresponded to about 140 and 14 mg/kg body weight (dermal administration) and 1.4 mg/kg body weight (intradermal administration). In the experiments with dermal administration, animals were exposed for 8 hours and sacrificed 8, 24 or 120 h after beginning of exposure. In the experiment with intradermal administration, animals were sacrificed 120 h after treatment. After dermal administration of 14 C-MDI, mean recoveries of radioactivity from all dose groups were in the range from 97.86 to 108.07% of the total radioactivity administered. Generally, the largest proportion of radioactivity was found at the application site and dressing. The total amount of radioactivity absorbed (including excreta, cage wash, tissues/organs and carcass) increased with increasing sacrifice time. Dermal absorption was very low and quantitatively similar at both dose levels; maximally ca. 0.9 % of the applied radioactivity was absorbed. After intradermal administration of 14 C-MDI, the mean recovery of radioactivity was 100.90 % of the radioactivity administered. The largest proportion of radioactivity was found at the application site. The total amount of radioactivity absorbed (including excreta, cage wash, tissues/organs and carcass) amounted to about 26 % of the radioactivity applied. Irrespective of the mode of administration of 1 4C -MDI, concentrations of radioactivity in tissues and organs generally were below 1 μg Eq/g at 120 h after administration. In summary, the results of this study comparing systemic

  13. Study of an ejector-absorption refrigeration cycle with an adaptable ejector nozzle for different working conditions

    International Nuclear Information System (INIS)

    Vereda, C.; Ventas, R.; Lecuona, A.; Venegas, M.

    2012-01-01

    Highlights: ► An absorption refrigeration cycle with an ejector device at the absorber inlet is presented. ► This cycle is able to reduce up to 9 °C the temperature of onset of refrigerant generation without extra energy consumption. ► At very low driving temperatures it allows increasing the cooling capacity. ► The ejector device proposed has a partially variable geometry and we study its influence on the cycle performances. -- Abstract: This paper presents a numerical model of an ejector-absorption (single-effect) refrigeration cycle with ammonia–lithium nitrate solution as working fluid, operating under steady-state conditions. In this cycle, the ejector is located at the absorber inlet replacing the solution expansion valve. The liquid–gas ejector entrains refrigerant vapor from the evaporator; this way the absorber pressure becomes higher than the evaporator pressure without any additional energy consumption. The objective of this numerical model is to evaluate the influence of the ejector geometry on the cycle performances and to determine the range of the heat source temperature in which it is convenient to use a practical ejector in the absorption cycle. The simulation is based on UA-ΔT lm models for separate heat transfer regions in a novel implementation using plate-type heat exchangers and this way the results are offered as a function of the external temperatures. This study focuses on evaluating the feasibility of an ejector whose nozzle area is adjustable while the rest of the ejector dimensions are fixed, thus being more feasible than complete variable geometry ejectors. The cycle performance is reported for different mixing tube constant diameters. Results of the simulation show that the use of an ejector allows, among others, to decrease the activation temperature approximately 9 °C in respect to the conventional single-effect absorption cycle and increasing the COP for moderate temperatures. The variable ejector nozzle geometry is

  14. A Literature Study of Matrix Element Influenced to the Result of Analysis Using Absorption Atomic Spectroscopy Method (AAS)

    International Nuclear Information System (INIS)

    Tyas-Djuhariningrum

    2004-01-01

    The gold sample analysis can be deviated more than >10% to those thrue value caused by the matrix element. So that the matrix element character need to be study in order to reduce the deviation. In rock samples, the matrix elements can cause self quenching, self absorption and ionization process, so there is a result analysis error. In the rock geochemical process, the elements of the same group at the periodic system have the tendency to be together because of their same characteristic. In absorption Atomic Spectroscopy analysis, the elements associate can absorb primer energy with similar wave length so that it can cause deviation in the result interpretation. The aim of study is to predict matrix element influences from rock sample with application standard method for reducing deviation. In quantitative way, assessment of primer light intensity that will be absorbed is proportional to the concentration atom in the sample that relationship between photon intensity with concentration in part per million is linier (ppm). These methods for eliminating matrix elements influence consist of three methods : external standard method, internal standard method, and addition standard method. External standard method for all matrix element, internal standard method for elimination matrix element that have similar characteristics, addition standard methods for elimination matrix elements in Au, Pt samples. The third of standard posess here accuracy are about 95-97%. (author)

  15. Using resonance light scattering and UV/vis absorption spectroscopy to study the interaction between gliclazide and bovine serum albumin.

    Science.gov (United States)

    Zhang, Qiu-Ju; Liu, Bao-Sheng; Li, Gai-Xia; Han, Rong

    2016-08-01

    At different temperatures (298, 310 and 318 K), the interaction between gliclazide and bovine serum albumin (BSA) was investigated using fluorescence quenching spectroscopy, resonance light scattering spectroscopy and UV/vis absorption spectroscopy. The first method studied changes in the fluorescence of BSA on addition of gliclazide, and the latter two methods studied the spectral change in gliclazide while BSA was being added. The results indicated that the quenching mechanism between BSA and gliclazide was static. The binding constant (Ka ), number of binding sites (n), thermodynamic parameters, binding forces and Hill's coefficient were calculated at three temperatures. Values for the binding constant obtained using resonance light scattering and UV/vis absorption spectroscopy were much greater than those obtained from fluorescence quenching spectroscopy, indicating that methods monitoring gliclazide were more accurate and reasonable. In addition, the results suggest that other residues are involved in the reaction and the mode 'point to surface' existed in the interaction between BSA and gliclazide. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  16. Copper doped TiO2 nanoparticles characterized by X-ray absorption spectroscopy, total scattering, and powder diffraction--a benchmark structure-property study.

    Science.gov (United States)

    Lock, Nina; Jensen, Ellen M L; Mi, Jianli; Mamakhel, Aref; Norén, Katarina; Qingbo, Meng; Iversen, Bo B

    2013-07-14

    Metal functionalized nanoparticles potentially have improved properties e.g. in catalytic applications, but their precise structures are often very challenging to determine. Here we report a structural benchmark study based on tetragonal anatase TiO2 nanoparticles containing 0-2 wt% copper. The particles were synthesized by continuous flow synthesis under supercritical water-isopropanol conditions. Size determination using synchrotron PXRD, TEM, and X-ray total scattering reveals 5-7 nm monodisperse particles. The precise dopant structure and thermal stability of the highly crystalline powders were characterized by X-ray absorption spectroscopy and multi-temperature synchrotron PXRD (300-1000 K). The combined evidence reveals that copper is present as a dopant on the particle surfaces, most likely in an amorphous oxide or hydroxide shell. UV-VIS spectroscopy shows that copper presence at concentrations higher than 0.3 wt% lowers the band gap energy. The particles are unaffected by heating to 600 K, while growth and partial transformation to rutile TiO2 occur at higher temperatures. Anisotropic unit cell behavior of anatase is observed as a consequence of the particle growth (a decreases and c increases).

  17. X-ray absorption and Raman spectroscopy studies of molybdenum environments in borosilicate waste glasses

    Energy Technology Data Exchange (ETDEWEB)

    McKeown, David A., E-mail: davidm@vsl.cua.edu; Gan, Hao; Pegg, Ian L.

    2017-05-15

    Mo-containing high-level nuclear waste borosilicate glasses were investigated as part of an effort to improve Mo loading while avoiding yellow phase crystallization. Previous work showed that additions of vanadium decrease yellow phase formation and increases Mo solubility. X-ray absorption spectroscopy (XAS) and Raman spectroscopy were used to characterize Mo environments in HLW borosilicate glasses and to investigate possible structural relationships between Mo and V. Mo XAS spectra for the glasses indicate isolated tetrahedral Mo{sup 6+}O{sub 4} with Mo-O distances near 1.75 Å. V XANES indicate tetrahedral V{sup 5+}O{sub 4} as the dominant species. Raman spectra show composition dependent trends, where Mo-O symmetrical stretch mode frequencies (ν{sub 1}) are sensitive to the mix of alkali and alkaline earth cations, decreasing by up to 10 cm{sup −1} for glasses that change from Li{sup +} to Na{sup +} as the dominant network-modifying species. This indicates that MoO{sub 4} tetrahedra are isolated from the borosilicate network and are surrounded, at least partly, by Na{sup +} and Li{sup +}. Secondary ν{sub 1} frequency effects, with changes up to 7 cm{sup −1}, were also observed with increasing V{sub 2}O{sub 5} and MoO{sub 3} content. These secondary trends may indicate MoO{sub 4}-MoO{sub 4} and MoO{sub 4}-VO{sub 4} clustering, suggesting that V additions may stabilize Mo in the matrix with respect to yellow phase formation. - Highlights: •Raman and XAS data indicate isolated MoO{sub 4} tetrahedra from the borosilicate network. •Mo-O stretch frequency is sensitive to network-modifying Li and Na concentrations. •Mo-O stretch frequency shifts were also seen with increasing V{sub 2}O{sub 5} and MoO{sub 3} content. •The Raman trends may indicate MoO{sub 4}-MoO{sub 4} and MoO{sub 4}-VO{sub 4} clustering in the glass. •V may stabilize Mo in the glass matrix avoiding yellow phase formation.

  18. Ultrasonic velocity and absorption study of binary mixtures of cyclohexane with acrylonitrile by interferometric method at different frequencies

    Science.gov (United States)

    Pawar, N. R.; Chimankar, O. P.; Bhandakkar, V. D.; Padole, N. N.

    2012-12-01

    The ultrasonic velocity (u), absorption (α), density (ρ), and viscosity (η) has been measured at different frequencies (1MHz to 10MHz) in the binary mixtures of cyclohexane with acrylonitriile over the entire range of composition at temperature 303K. Vander Waal's constant (b), adiabatic compressibility (βa), acoustic impedance (Z), molar volume (V), free length (Lf), free volume, internal pressure, intermolecular radius and relative association have been also calculated. A special application for acrylonitrile is in the manufacture of carbon fibers. These are produced by paralysis of oriented poly acrylonitrile fibers and are used to reinforce composites for high-performance applications in the aircraft, defense and aerospace industries. Other applications of acrylonitrile are in the production of fatty amines, ion exchange resins and fatty amine amides used in cosmetics, adhesives, corrosion inhibitors and water-treatment resins. Cyclohexane derivatives can be used for the synthesis of pharmaceuticals, dyes, herbicides, plant growth regulator, plasticizers, rubber chemicals, nylon, cyclamens and other organic compounds. In the view of these extensive applications of acrylonitrile and cyclohexane in the engineering process, textile and pharmaceutical industries present study provides qualitative information regarding the nature and strength of interaction in the liquid mixtures through derive parameters from ultrasonic velocity and absorption measurement.

  19. Reduced absorption and enhanced synthesis of cholesterol in patients with cystic fibrosis: a preliminary study of plasma sterols.

    Science.gov (United States)

    Gelzo, Monica; Sica, Concetta; Elce, Ausilia; Dello Russo, Antonio; Iacotucci, Paola; Carnovale, Vincenzo; Raia, Valeria; Salvatore, Donatello; Corso, Gaetano; Castaldo, Giuseppe

    2016-09-01

    Low cholesterol is typically observed in the plasma of patients with cystic fibrosis (CF) contrasting with the subcellular accumulation of cholesterol demonstrated in CF cells and in mice models. However, the homeostasis of cholesterol has not been well investigated in patients with CF. We studied the plasma of 26 patients with CF and 33 unaffected controls campesterol and β-sitosterol as markers of intestinal absorption and lathosterol as a marker of de novo cholesterol biosynthesis by gas chromatography (GC-FID and GC-MS). Plasma campesterol and β-sitosterol results were significantly (p=0.01) lower while plasma lathosterol was significantly higher (p=0.001) in patients with CF as compared to control subjects. Plasma cholesterol results were significantly lower (p=0.01) in CF patients. Our data suggest that the impaired intestinal absorption of exogenous sterols in patients with CF stimulates the endogenous synthesis of cholesterol, but the levels of total cholesterol in plasma remain lower. This may be due to the CFTR dysfunction that reduces cholesterol blood excretion causing the accumulation of cholesterol in liver cells and in other tissues contributing to trigger CF chronic inflammation.

  20. Study on rice absorption and distribution of Cd in applying Zn fertilizer with 65Zn, 115Cdm tracing technique

    International Nuclear Information System (INIS)

    Tang Nianxin; Shen Jinxiong

    1994-01-01

    Results of study by using 65 Zn and 115 Cd m tracers show that, along with the increase of the amount of Cd in applying Zn fertilizer to soil, rice has the phenomena of growth retard and tiller delay in the earlier growing stage. The inhibiting phenomenon is lightened along with the progress of rice growth. Very small quantity of Cd might be helpful to the growth of rice. It would cause serious inhibition to rice growth when the amount of Cd reaches to a definite limitation (64 x 10 -6 ). The distribution of Cd in a rice plant follows the following order in content: root>stem and leaves>brown rice>ear stalk>rice shell. Cd is mainly accumulated in rice root, taking 90% of the total amount of Cd contained in whole rice plant. The amount of Cd absorbed by rice increases with the amount of Cd applied to soil, though the total absorption extremely low, for example, only about 0.1% of the applied amount could be absorbed by two crops of rice, most of the applied Cd still retains in soil. Less and less Zn could be absorbed and utilized by rice along with the increase of the amount of the applied Cd. Application of Mn fertilizer affects negatively the absorption of Cd by rice, especially in brown rice

  1. Occupied and unoccupied electronic structures of an L-cysteine film studied by core-absorption and resonant photoelectron spectroscopies

    Science.gov (United States)

    Kamada, M.; Hideshima, T.; Azuma, J.; Yamamoto, I.; Imamura, M.; Takahashi, K.

    2016-04-01

    Unoccupied and occupied electronic structures of an L-cysteine film have been studied by absorption and resonant photoelectron spectroscopies. Core absorptions at S-L, C-K, N-K, and O-K levels indicate that the lower unoccupied states are predominantly composed of oxygen-2p, carbon-2p, and sulfur-4s+3d orbitals, while higher unoccupied states may be attributed dominantly to nitrogen-np (n ≥ 3), oxygen-np (n ≥ 3), and sulfur-ns+md (n ≥ 4, m ≥ 3) orbitals. Resonant photoelectron spectra at S-L23 and O-K levels indicate that the highest occupied state is originated from sulfur-3sp orbitals, while oxygen-2sp orbitals contribute to the deeper valence states. The delocalization lifetimes of the oxygen-1s and sulfur-2p excited states are estimated from a core-hole clock method to be about 9 ± 1 and 125 ± 25 fs, respectively.

  2. Occupied and unoccupied electronic structures of an L-cysteine film studied by core-absorption and resonant photoelectron spectroscopies

    Energy Technology Data Exchange (ETDEWEB)

    Kamada, M., E-mail: kamada@cc.saga-u.ac.jp; Hideshima, T.; Azuma, J.; Yamamoto, I.; Imamura, M.; Takahashi, K. [Synchrotron Light Application Center, Saga University, Honjo 1, Saga 840-8502 (Japan)

    2016-04-15

    Unoccupied and occupied electronic structures of an L-cysteine film have been studied by absorption and resonant photoelectron spectroscopies. Core absorptions at S-L, C-K, N-K, and O-K levels indicate that the lower unoccupied states are predominantly composed of oxygen-2p, carbon-2p, and sulfur-4s+3d orbitals, while higher unoccupied states may be attributed dominantly to nitrogen-np (n ≥ 3), oxygen-np (n ≥ 3), and sulfur-ns+md (n ≥ 4,  m ≥ 3) orbitals. Resonant photoelectron spectra at S-L{sub 23} and O-K levels indicate that the highest occupied state is originated from sulfur-3sp orbitals, while oxygen-2sp orbitals contribute to the deeper valence states. The delocalization lifetimes of the oxygen-1s and sulfur-2p excited states are estimated from a core-hole clock method to be about 9 ± 1 and 125 ± 25 fs, respectively.

  3. Study of Cr(VI) adsorption onto magnetite nanoparticles using synchrotron-based X-ray absorption spectroscopy

    Science.gov (United States)

    Chen, Yen-Hua; Liu, Dian-Yu; Lee, Jyh-Fu

    2018-04-01

    In this study, the efficiency of Cr(VI) adsorption onto nano-magnetite was examined by batch experiments, and the Cr(VI) adsorption mechanism was investigated using synchrotron-based X-ray absorption spectroscopy. Magnetite nanoparticles with a mean diameter of 10 nm were synthesized using an inexpensive and simple co-precipitation method. It shows a saturation magnetization of 54.3 emu/g, which can be recovered with an external magnetic field. The adsorption data fitted the Langmuir adsorption isotherm well, implying a monolayer adsorption behavior of Cr(VI) onto nano-magnetite. X-ray absorption spectroscopy results indicate that the adsorption mechanism involves electron transfer between Fe(II) in nano-magnetite (Fe2+OFe3+ 2O3) and Cr(VI) to transform into Cr(III), which may exist as an Fe(III)-Cr(III) mixed solid phase. Moreover, the Cr(III)/Cr(VI) ratio in the final products can be determined by the characteristic pre-edge peak area of Cr(VI) in the Cr K-edge spectrum. These findings suggest that nano-magnetite is effective for Cr(VI) removal from wastewater because it can transform highly poisonous Cr(VI) species into nontoxic Cr(III) compounds, which are highly insoluble and immobile under environmental conditions.

  4. Optical and structural properties of plasma-treated Cordyceps bassiana spores as studied by circular dichroism, absorption, and fluorescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Geon Joon, E-mail: gjlee@kw.ac.kr; Sim, Geon Bo; Choi, Eun Ha [Plasma Bioscience Research Center/Department of Electrical and Biological Physics, Kwangwoon University, Seoul 139-701 (Korea, Republic of); Kwon, Young-Wan [KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 136-701 (Korea, Republic of); Kim, Jun Young; Jang, Siun; Kim, Seong Hwan, E-mail: piceae@naver.com [Department of Microbiology and Institute of Basic Sciences, Dankook University, Cheonan 330-714 (Korea, Republic of)

    2015-01-14

    To understand the killing mechanism of fungal spores by plasma treatment, the optical, structural, and biological properties of the insect pathogenic fungus Cordyceps bassiana spores were studied. A nonthermal atmospheric-pressure plasma jet (APPJ) was used to treat the spores in aqueous solution. Optical emission spectra of the APPJ acquired in air indicated emission peaks corresponding to hydroxyl radicals and atomic oxygen. When the APPJ entered the aqueous solution, additional reactive species were derived from the interaction of plasma radicals with the aqueous solution. Fluorescence and absorption spectroscopy confirmed the generation of hydroxyl radicals and hydrogen peroxide in the plasma-activated water (PAW). Spore counting showed that plasma treatment significantly reduced spore viability. Absorption spectroscopy, circular dichroism (CD) spectroscopy, and agarose gel electrophoresis of the DNA extracted from plasma-treated spores showed a reduction in spore DNA content. The magnitude of the dip in the CD spectrum was lower in the plasma-treated spores than in the control, indicating that plasma treatment causes structural modifications and/or damage to cellular components. Tryptophan fluorescence intensity was lower in the plasma-treated spores than in the control, suggesting that plasma treatment modified cell wall proteins. Changes in spore viability and DNA content were attributed to structural modification of the cell wall by reactive species coming from the APPJ and the PAW. Our results provided evidence that the plasma radicals and the derived reactive species play critical roles in fungal spore inactivation.

  5. Experimental and theoretical study of X-ray absorption around the chlorine L edge in vinyl chloride

    International Nuclear Information System (INIS)

    Kawerk, Elie; Carniato, Stéphane; Iwayama, Hiroshi; Shigemasa, Eiji; Piancastelli, Maria Novella; Wassaf, Joseph; Khoury, Antonio; Simon, Marc

    2013-01-01

    Highlights: ► We measured the X-ray absorption spectrum of C 2 H 3 Cl around the chlorine L edge. ► Ab-initio calculations of the spectrum shed light on eventual electronic resonances. ► Vibrational substructures for particular core excited states are considered. ► The potential energy surfaces of the core excited electronic states are evaluated. ► Sharp or narrow spectral bands are associated to bound or dissociative surfaces. -- Abstract: We present a combined experimental and theoretical study of the high-resolution chlorine L edge X-ray absorption spectrum in gas-phase vinyl chloride (C 2 H 3 Cl). With the help of ab-initio calculations, we interpret the experimental spectrum and attribute each band to its corresponding electronic transitions terminating at states characterized by an either binding or dissociative potential energy surface (PES). Vibrational substructures in some specific core-excited electronic states are taken into account

  6. Experimental and theoretical study of X-ray absorption around the chlorine L edge in vinyl chloride

    Energy Technology Data Exchange (ETDEWEB)

    Kawerk, Elie, E-mail: elie.kawerk@etu.upmc.fr [Université Pierre et Marie Curie, Laboratoire de Chimie Physique-Matière et Rayonnement, UMR 7614, 11 rue Pierre et Marie Curie, 75231 Paris Cedex 05 (France); Université Libanaise, Faculté des Sciences II Fanar, Laboratoire de Physique Appliquée, 90656 Jdeidet el Metn (Lebanon); Carniato, Stéphane [Université Pierre et Marie Curie, Laboratoire de Chimie Physique-Matière et Rayonnement, UMR 7614, 11 rue Pierre et Marie Curie, 75231 Paris Cedex 05 (France); Iwayama, Hiroshi; Shigemasa, Eiji [Ultraviolet Synchrotron Orbital Radiation Facility, Institute for Molecular Science, Okazaki 444-8585 (Japan); Piancastelli, Maria Novella [Université Pierre et Marie Curie, Laboratoire de Chimie Physique-Matière et Rayonnement, UMR 7614, 11 rue Pierre et Marie Curie, 75231 Paris Cedex 05 (France); Wassaf, Joseph; Khoury, Antonio [Université Libanaise, Faculté des Sciences II Fanar, Laboratoire de Physique Appliquée, 90656 Jdeidet el Metn (Lebanon); Simon, Marc [Université Pierre et Marie Curie, Laboratoire de Chimie Physique-Matière et Rayonnement, UMR 7614, 11 rue Pierre et Marie Curie, 75231 Paris Cedex 05 (France)

    2013-02-15

    Highlights: ► We measured the X-ray absorption spectrum of C{sub 2}H{sub 3}Cl around the chlorine L edge. ► Ab-initio calculations of the spectrum shed light on eventual electronic resonances. ► Vibrational substructures for particular core excited states are considered. ► The potential energy surfaces of the core excited electronic states are evaluated. ► Sharp or narrow spectral bands are associated to bound or dissociative surfaces. -- Abstract: We present a combined experimental and theoretical study of the high-resolution chlorine L edge X-ray absorption spectrum in gas-phase vinyl chloride (C{sub 2}H{sub 3}Cl). With the help of ab-initio calculations, we interpret the experimental spectrum and attribute each band to its corresponding electronic transitions terminating at states characterized by an either binding or dissociative potential energy surface (PES). Vibrational substructures in some specific core-excited electronic states are taken into account.

  7. A Comparative Study of Molecular Structure, pKa, Lipophilicity, Solubility, Absorption and Polar Surface Area of Some Antiplatelet Drugs

    Directory of Open Access Journals (Sweden)

    Milan Remko

    2016-03-01

    Full Text Available Theoretical chemistry methods have been used to study the molecular properties of antiplatelet agents (ticlopidine, clopidogrel, prasugrel, elinogrel, ticagrelor and cangrelor and several thiol-containing active metabolites. The geometries and energies of most stable conformers of these drugs have been computed at the Becke3LYP/6-311++G(d,p level of density functional theory. Computed dissociation constants show that the active metabolites of prodrugs (ticlopidine, clopidogrel and prasugrel and drugs elinogrel and cangrelor are completely ionized at pH 7.4. Both ticagrelor and its active metabolite are present at pH = 7.4 in neutral undissociated form. The thienopyridine prodrugs ticlopidine, clopidogrel and prasugrel are lipophilic and insoluble in water. Their lipophilicity is very high (about 2.5–3.5 logP values. The polar surface area, with regard to the structurally-heterogeneous character of these antiplatelet drugs, is from very large interval of values of 3–255 Å2. Thienopyridine prodrugs, like ticlopidine, clopidogrel and prasugrel, with the lowest polar surface area (PSA values, exhibit the largest absorption. A high value of polar surface area (PSA of cangrelor (255 Å2 results in substantial worsening of the absorption in comparison with thienopyridine drugs.

  8. Coupling between mass transfer and chemical reactions during the absorption of CO2 in a NaHCO3-Na2CO3 brine :experimental and theoretical study

    OpenAIRE

    Wylock, Christophe; Colinet, Pierre; Cartage, Thierry; Haut, Benoît

    2008-01-01

    This work deals with the study of the gas-liquid mass transfer, coupled with chemical reactions. The case of carbonic gas absorption in a brine of sodium carbonate and bicarbonate is investigated. It is performed in collaboration with Solvay SA. The aim of this work is to get a better understanding of this phenomenon. It would permit an optimization of the refined sodium bicarbonate production process. The basis of developed mathematical models is presented. The CO2 absorption is coupled with...

  9. Quantification of body iron and iron absorption in the REDS-II Donor Iron Status Evaluation (RISE) study.

    Science.gov (United States)

    Kiss, Joseph E; Birch, Rebecca J; Steele, Whitney R; Wright, David J; Cable, Ritchard G

    2017-07-01

    Repeated blood donation alters the iron balance of blood donors. We quantified these effects by analyzing changes in body iron as well as calculating iron absorbed per day for donors enrolled in a prospective study. For 1308 donors who completed a final study visit, we calculated total body iron at the enrollment and final visits and the change in total body iron over the course of the study. Taking into account iron lost from blood donations during the study and obligate losses, we also calculated the average amount of iron absorbed per day. First-time/reactivated donors at enrollment had iron stores comparable to previous general population estimates. Repeat donors had greater donation intensity and greater mean iron losses than first-time/reactivated donors, yet they had little change in total body iron over the study period, whereas first-time/reactivated donors had an average 35% drop. There was higher estimated iron absorption in the repeat donors (men: 4.49 mg/day [95% confidence interval [CI], 4.41-4.58 mg/day]; women: 3.75 mg/day [95% CI, 3.67-3.84 mg/day]) compared with estimated iron absorption in first-time/reactivated donors (men: 2.89 mg/day [95% CI, 2.75-3.04 mg/day]; women: 2.76 mg/day [95% CI, 2.64-2.87 mg/day]). The threshold for negative estimated iron stores (below "0" mg/kg stores) was correlated with the development of anemia at a plasma ferritin value of 10 ng/mL. These analyses provide quantitative data on changes in estimated total body iron for a broad spectrum of blood donors. In contrast to using ferritin alone, this model allows assessment of the iron content of red blood cells and the degree of both iron surplus and depletion over time. © 2017 AABB.

  10. Extended x-ray absorption fine structure spectroscopy and x-ray absorption near edge spectroscopy study of aliovalent doped ceria to correlate local structural changes with oxygen vacancies clustering

    Energy Technology Data Exchange (ETDEWEB)

    Shirbhate, S. C.; Acharya, S. A., E-mail: saha275@yahoo.com [Department of Physics, Rashtrasant Tukadoji Maharaj Nagpur University, Nagpur 440033 (India); Yadav, A. K. [Atomic and molecular Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2016-04-04

    This study provides atomic scale insight to understand the role of aliovalent dopants on oxygen vacancies clustering and dissociation mechanism in ceria system in order to enhance the performance of oxy-ion conductor. Dopants induced microscale changes in ceria are probed by extended X-ray absorption fine structure spectroscopy, X-ray absorption near edge spectra, and Raman spectroscopy. The results are explored to establish a correlation between atomic level structural changes (coordination number, interatomic spacing) → formation of dimer and trimer type cation-oxygen vacancies defect complex (intrinsic and extrinsic) → dissociation of oxygen vacancies from defect cluster → ionic conductivity temperature. It is a strategic approach to understand key physics of ionic conductivity mechanism in order to reduce operating temperature of electrolytes for intermediate temperature (300–450 °C) electrochemical devices for the first time.

  11. Mn L{sub 2,3}-edge X-ray absorption spectroscopic studies on charge-discharge mechanism of Li{sub 2}MnO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Kubobuchi, Kei, E-mail: kubobuchi@nissan-arc.co.jp [NISSAN ARC Ltd., 1 Natsushima, Yokosuka 237-0061 (Japan); Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8505, Japan. (Japan); Mogi, Masato; Imai, Hideto [NISSAN ARC Ltd., 1 Natsushima, Yokosuka 237-0061 (Japan); Ikeno, Hidekazu [Osaka Prefecture University, 1-2 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8570 (Japan); Tanaka, Isao [Department of Materials Science and Engineering, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501 (Japan); Mizoguchi, Teruyasu, E-mail: teru@iis.u-tokyo.ac.jp [Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8505, Japan. (Japan)

    2014-02-03

    The redox reaction of Mn in Li{sub 2}MnO{sub 3} was studied by X-ray absorption spectroscopy and ab initio multiplet calculation. Associated with the de-intercalation of Li-ion, small but clear spectral changes were observed in Mn-L{sub 2,3} X-ray absorption near edge structure (XANES). The systematic ab initio multiplet calculations of Mn-L{sub 2,3} XANES revealed that the spectral changes in the experiment could not simply be ascribed to the change of the valency from Mn{sup 4+} to Mn{sup 5+} but can be explained well by the changes of local atomic structures around Mn{sup 4+} due to the Li de-intercalation. Our results suggest that the electronic state of oxygen should change during charging in Li{sub 2}MnO{sub 3}.

  12. Electron delocalization in cyanide-bridged coordination polymer electrodes for Li-ion batteries studied by soft x-ray absorption spectroscopy

    NARCIS (Netherlands)

    Asakura, Daisuke; Okubo, Masashi; Mizuno, Yoshifumi; Kudo, Tetsuichi; Zhou, Haoshen; Amemiya, Kenta; de Groot, Frank M. F.; Chen, Jeng-Lung; Wang, Wei-Cheng; Glans, Per-Anders; Chang, Chinglin; Guo, Jinghua; Honma, Itaru

    2011-01-01

    The electronic structure change during the reversible Li-ion storage reaction in a bimetallic MnFe-Prussian blue analogue (Li(x)K(0.14)Mn(1.43)[Fe(CN)(6)] center dot 6H(2)O) was investigated by soft x-ray absorption spectroscopy. The Mn L(2,3)-edgespectra revealed the unchanged Mn(2+) high-spin

  13. G5 PAMAM dendrimer versus liposome: a comparison study on the in vitro transepithelial transport and in vivo oral absorption of simvastatin.

    Science.gov (United States)

    Qi, Rong; Zhang, Heran; Xu, Lu; Shen, Wenwen; Chen, Cong; Wang, Chao; Cao, Yini; Wang, Yunan; van Dongen, Mallory A; He, Bing; Wang, Siling; Liu, George; Banaszak Holl, Mark M; Zhang, Qiang

    2015-07-01

    This study compared formulation effects of a dendrimer and a liposome preparation on the water solubility, transepithelial transport, and oral bioavailability of simvastatin (SMV). Amine-terminated G5 PAMAM dendrimer (G5-NH2) was chosen to form SMV/G5-NH2 molecular complexes, and SMV-liposomes were prepared by using a thin film dispersion method. The effects of these preparations on the transepithelial transport were investigated in vitro using Caco-2 cell monolayers. Results indicated that the solubility and transepithelial transport of SMV were significantly improved by both formulations. Pharmacokinetic studies in rats also revealed that both the SMV/G5-NH2 molecular complexes and the SMV-liposomes significantly improved the oral bioavailability of SMV with the liposomes being more effective than the G5-NH2. The overall better oral absorption of SMV-liposomes as compared to SMV/G5-NH2 molecular complexes appeared to arise from better liposomal solubilization and encapsulation of SMV and more efficient intracellular SMV delivery. Various carrier systems have been designed to enhance drug delivery via the oral route. In this study, the authors compared G5 PAMAM dendrimers to liposome preparations in terms of solubility, transepithelial transport, and oral bioavailability of this poorly water-soluble drug. This understanding has improved our knowledge in the further development of drug carrier systems. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Study of heavy metals in the grass-milk product chain by means of neutron activation and atomic absorption

    Energy Technology Data Exchange (ETDEWEB)

    Bruant, C; Bruant, J P; Neuburger, M; Vassal, L; Disant, C; Bittel, R; Fourcy, A

    1974-12-31

    with the heavy metals Hg, Cu, Zn, Pb, and Cd is studied. The first three metals were determined by neutron activation and tae last two by atomic absorption spectrophotometry. The chemical rature of these metals and their biological effect leads to different results from those obtained for tae principal fission products. As a rule the heavy metal concentrations at harvest are much lower than taat of the foods ingested by lactating cows. The cow plays the role of filter. If the concentration of these elements is considered in mu g/g of fresh material there is a reconcentration of these heavy metals in cream and cheese, probably cornected with their physico-chemical affinity for proteins. (JSR)

  15. Carbon dioxide adsorption on a ZnO(101[combining macron]0) substrate studied by infrared reflection absorption spectroscopy.

    Science.gov (United States)

    Buchholz, Maria; Weidler, Peter G; Bebensee, Fabian; Nefedov, Alexei; Wöll, Christof

    2014-01-28

    The adsorption of carbon dioxide on the mixed-terminated ZnO(101[combining macron]0) surface of a bulk single crystal was studied by UHV Infrared Reflection Absorption Spectroscopy (IRRAS). In contrast to metals, the classic surface selection rule for IRRAS does not apply to bulk oxide crystals, and hence vibrational bands can also be observed for s-polarized light. Although this fact substantially complicates data interpretation, a careful analysis allows for a direct determination of the adsorbate geometry. Here, we demonstrate the huge potential of IR-spectroscopy for investigations on oxide single crystal surfaces by considering all three components of the incident polarized light separately. We find that the tridentate (surface) carbonate is aligned along the [0001] direction. A comparison to data reported previously for CO2 adsorbed on the surfaces of ZnO nanoparticles provides important insight into the role of defects in the surface chemistry of powder particles.

  16. Adsorption of 3,4-ethylenedioxythiophene (EDOT) on noble metal surfaces: A photoemission and X-ray absorption study

    International Nuclear Information System (INIS)

    Pasquali, L.; Terzi, F.; Montecchi, M.; Doyle, B.P.; Lukkari, J.; Zanfrognini, B.; Seeber, R.; Nannarone, S.

    2009-01-01

    The adsorption of 3,4-ethylenedioxythiophene (EDOT) on Au and Pt surfaces is studied by core level and valence band photoemission using synchrotron radiation and by near edge X-ray absorption spectroscopy. To closer simulate real applications, the films are grown from aqueous solution at room temperature and are compared to an 'ideal' film prepared by dosing the molecules from the vapour phase on a clean Au(1 1 1) single crystal. The S 2p, C 1s and O 1s levels show multiple components which are associated to molecular fragmentation. NEXAFS confirms that fragmentation takes place at the surface. Thiophene species as well as alkyl chains and S n species are identified as the most probable fragmentation products.

  17. Simulation study of the thermal and the thermoelastic effects induced by pulsed laser absorption in human skin

    Science.gov (United States)

    Kim, Jae-Young; Jang, Kyungmin; Yang, Seung-Jin; Baek, Jun-Hyeok; Park, Jong-Rak; Yeom, Dong-Il; Kim, Ji-Sun; Kim, Hyung-Sik; Jun, Jae-Hoon; Chung, Soon-Cheol

    2016-04-01

    We studied the thermal and the mechanical effects induced by pulsed laser absorption in human skin by numerically solving the heat-transfer and the thermoelastic wave equations. The simulation of the heat-transfer equation yielded the spatiotemporal distribution of the temperature increase in the skin, which was then used in the driving term of the thermoelastic wave equation. We compared our simulation results for the temperature increase and the skin displacements with the measured and numerical results, respectively. For the comparison, we used a recent report by Jun et al. [Sci. Rep. 5, 11016 (2015)], who measured in vivo skin temperature and performed numerical simulation of the thermoelastic wave equation using a simple assumption about the temporal evolution of the temperature distribution, and found their results to be in good agreement with our results. In addition, we obtained solutions for the stresses in the human skin and analyzed their dynamic behaviors in detail.

  18. Study of new technique of solid combustible materials to determination of volatile elements by flame atomic absorption spectrophotometry

    International Nuclear Information System (INIS)

    Campos, R.C. de.

    1988-01-01

    A new technique for direct trace element analysis of solid combustible materials is described. The samples (up to 10 mg) are weighed on a graphite platform wich is then placed in a quartz tube, at the focal point of three infrared lamps. When the lamps are turned on, the sample burns in a stream of air, and the resulting dry aerosol containing volatile elements such as Hg, Cd, Bi, Tl, Zn, Pb and Cu is carried into the mixing chamber and thence into the flame, where the atomic absorption measurement is carried out. This technique overcomes chemical sample preparation steps, avoiding contaminations of losses associated with these steps. A ''furnace in flame'' system where the aerosol is transported to a flame heated T-tube is also described. The influence of flame stoichiometry, observation height, platform material and air flux intensity was studied inorder to determine optimal analytical conditions. (author) [pt

  19. Disorder-induced enhancement of indirect absorption in a GeSn photodetector grown by molecular beam epitaxy

    International Nuclear Information System (INIS)

    Li, H.; Chang, C.; Cheng, H. H.; Sun, G.; Soref, R. A.

    2016-01-01

    We report an investigation on the absorption mechanism of a GeSn photodetector with 2.4% Sn composition in the active region. Responsivity is measured and absorption coefficient is calculated. Square root of absorption coefficient linearly depends on photon energy indicating an indirect transition. However, the absorption coefficient is found to be at least one order of magnitude higher than that of most other indirect materials, suggesting that the indirect optical absorption transition cannot be assisted only by phonon. Our analysis of absorption measurements by other groups on the same material system showed the values of absorption coefficient on the same order of magnitude. Our study reveals that the strong enhancement of absorption for the indirect optical transition is the result of alloy disorder from the incorporation of the much larger Sn atoms into the Ge lattice that are randomly distributed.

  20. Study of the dispersion phenomena connected with the absorption by recoilless nuclear resonance fluorescence; Etude des phenomenes de dispersion lies a l'absorption resonnante sans recul des noyaux atomiques

    Energy Technology Data Exchange (ETDEWEB)

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

    1965-12-01

    In nuclear resonance fluorescence as in the optical field abnormal dispersion curves are related to the absorption lines. It is possible, by using quadrupolar or magnetic splitting of the line in the case of recoilless resonance fluorescence (Moessbauer effect) to obtain differential dispersion effects between the two orthogonal linear or the two inverse circular components of the incident gamma radiation. These effects induce bi-refraction phenomena or Faraday rotation on the gamma beam, which have been studied on Fe-57 enriched absorbers. (author) [French] Comme dans le domaine optique, aux raies d'absorption de fluorescence resonnante des noyaux atomiques sont associees des courbes de dispersion anormale. Les decompositions des raies d'absorption de fluorescence resonnante sans recul (raies Moessbauer) par couplage quadrupolaire ou effet Zeeman permettent d'obtenir des effets dispersifs differentiels entre composantes lineaires orthogonales ou circulaires inverses du rayonnement gamma incident. Ces effets se traduisent par des phenomenes de birefringence ou de rotation Faraday, qui ont pu etre etudies sur des milieux enrichis en fer-57. (auteur)

  1. [Effect of Long-Term Fertilization on Organic Nitrogen Functional Groups in Black Soil as Revealed by Synchrotron-Based X-Ray Absorption Near-Edge Structure Spectroscopy].

    Science.gov (United States)

    Li, Hui; Gao, Qiang; Wang, Shuai; Zhu, Ping; Zhang, Jin-jing; Zhao, Yi-dong

    2015-07-01

    Nitrogen (N) is a common limiting nutrient in crop production. The N content of soil has been used as an important soil fertility index. Organic N is the major form of N in soil. In most agricultural surface soils, more than 90% of total N occurs in organic forms. Therefore, understanding the compositional characteristics of soil organic N functional groups can provide the scientific basis for formulating the reasonable farmland management strategies. Synchrotron radiation soft X-ray absorption near-edge structure (N K-edge XANES) spectroscopy is the most powerful tool to characterize in situ organic N functional groups compositions in soil. However, to our most knowledge, no studies have been conducted to examine the organic N functional groups compositions of soil using N K-edge XANES spectroscopy under long-term fertilization practices. Based on a long-term field experiment (started in 1990) in a black soil (Gongzhuling, Northeast China), we investigated the differences in organic N functional groups compositions in bulk soil and clay-size soil fraction among fertilization patterns using synchrotron-based N K- edge XANES spectroscopy. Composite soil samples (0-20 cm) were collected in 2008. The present study included six treatments: farmland fallow (FALL), no-fertilization control (CK), chemical nitrogen, phosphorus, and potassium fertilization (NPK), NPK in combination with organic manure (NPKM), 1.5 times of NPKM (1.5 NPKM), and NPK in combination with maize straw (NPKS). The results showed that N K-edge XANES spectra of all the treatments under study exhibited characteristic absorption peaks in the ranges of 401.2-401.6 and 402.7-403.1 eV, which were assigned as amides/amine-N and pyrrole-N, respectively. These characteristic absorption peaks were more obvious in clay-size soil fraction than in bulk soil. The results obtained from the semi-quantitative analysis of N K-edge XANES spectra indicated that the relative proportion of amides/amine-N was the highest

  2. Inhibition of starch absorption by dietary fibre. A comparative study of wheat bran, sugar-beet fibre, and pea fibre

    DEFF Research Database (Denmark)

    Hamberg, O; Rumessen, J J; Gudmand-Høyer, E

    1989-01-01

    The effect of dietary fibre on starch absorption was investigated in 8 healthy subjects. Amounts of starch escaping small-bowel absorption was assessed by comparison of breath H2 excretion after test meals and after lactulose (10g). After ingestion of bread made from 100g of wheat flour increases...

  3. Genesis of Co/SiO2 catalysts : XAS study at the cobalt L-III,L- II absorption edges

    NARCIS (Netherlands)

    Bazin, D.; Kovacs, I.; Guczi, L.; Parent, P.; Laffon, C.; De Groot, F.; Ducreux, O.; Lynch, J.

    2000-01-01

    Silica-supported cobalt catalysts have been investigated by soft X-ray absorption techniques. Soft X-ray absorption spectra were collected at the Co LII,III edge during in situ reduction of calcined samples in a stream of hydrogen in the temperature range between 300 and 650°C. Using reference

  4. Conformational aspects of proteins at the air/water interface studied by infrared reflection-absorption spectroscopy

    NARCIS (Netherlands)

    Martin, A.H.; Meinders, M.B.J.; Bos, M.A.; Cohen Stuart, M.A.; Vliet, T. van

    2003-01-01

    From absorption spectra obtained with infrared reflection - absorption spectroscopy (IRRAS), it is possible to obtain information on conformational changes at a secondary folding level of proteins adsorbed at the air/water interface. In addition, information on protein concentration at the interface

  5. Transition state region in the A-Band photodissociation of allyl iodide—A femtosecond extreme ultraviolet transient absorption study

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacherjee, Aditi, E-mail: abhattacherjee@berkeley.edu, E-mail: andrewattar@berkeley.edu; Attar, Andrew R., E-mail: abhattacherjee@berkeley.edu, E-mail: andrewattar@berkeley.edu [Department of Chemistry, University of California, Berkeley, California 94720 (United States); Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Leone, Stephen R., E-mail: srl@berkeley.edu [Department of Chemistry, University of California, Berkeley, California 94720 (United States); Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Department of Physics, University of California, Berkeley, California 94720 (United States)

    2016-03-28

    Femtosecond extreme ultraviolet (XUV) transient absorption spectroscopy based on a high-harmonic generation source is used to study the 266 nm induced A-band photodissociation dynamics of allyl iodide (CH{sub 2} =CHCH{sub 2}I). The photolysis of the C—I bond at this wavelength produces iodine atoms both in the ground ({sup 2}P{sub 3/2}, I) and spin-orbit excited ({sup 2}P{sub 1/2}, I*) states, with the latter as the predominant channel. Using XUV absorption at the iodine N{sub 4/5} edge (45–60 eV), the experiments constitute a direct probe of not only the long-lived atomic iodine reaction products but also the fleeting transition state region of the repulsive n{sub I}σ{sup ∗}{sub C—I} excited states. Specifically, three distinct features are identified in the XUV transient absorption spectrum at 45.3 eV, 47.4 eV, and 48.4 eV (denoted transients A, B, and C, respectively), which arise from the repulsive valence-excited nσ{sup ∗} states and project onto the high-lying core-excited states of the dissociating molecule via excitation of 4d(I) core electrons. Transients A and B originate from 4d(I) → n(I) core-to-valence transitions, whereas transient C is best assigned to a 4d(I) →σ{sup ∗}(C—I) transition. The measured differential absorbance of these new features along with the I/I* branching ratios known from the literature is used to suggest a more definitive assignment, albeit provisional, of the transients to specific dissociative states within the A-band manifold. The transients are found to peak around 55 fs–65 fs and decay completely by 145 fs–185 fs, demonstrating the ability of XUV spectroscopy to map the evolution of reactants into products in real time. The similarity in the energies of transients A and B with analogous features observed in methyl iodide [Attar et al. J. Phys. Chem. Lett. 6, 5072, (2015)] together with the new observation of transient C in the present work provides a more complete picture of the valence electronic

  6. X-ray absorption and emission study of amorphous and nanocrystalline GaN films containing buried N2

    International Nuclear Information System (INIS)

    Ruck, B.J.; Koo, A.; Budde, F.; Granville, S.; Trodahl, H.J.

    2004-01-01

    Full text: It has been predicted that amorphous gallium nitride (a-GaN) may possess a well-defined wide band gap, and is thus a potential substitute for the more expensive crystalline form used in short wavelength optoelectronic devices. Experimental investigations of disordered GaN have lent support to this prediction, but the picture is complicated because the properties of the amorphous state are not unique, and instead depend on the exact nature of the disordered structure. We have pioneered a novel ion-assisted growth technique that produces GaN films with a microstructure that ranges from nanocrystalline, with crystallite size of order 3 nm, to fully amorphous, depending on the exact growth conditions. This presentation will give an overview of our research into the properties of disordered GaN, including characterization of the physical structure of the films and their electronic energy levels, and also their photoconductive response. In particular I will focus on synchrotron radiation studies of samples with a range of different microstructures. X-ray absorption spectroscopy (XAS) and x-ray emission spectroscopy (XES) provide particularly powerful tools for examining a sample's empty and filled electronic energy levels, respectively. The details of the absorption and emission processes make it possible to obtain atom-specific information and to investigate the symmetry of the electronic levels. An example of the information obtained is shown. The thin solid curve shows XAS data, which is a measure of the nitrogen /7-projected density of unfilled electronic states in this nanocrystalline GaN sample. The thick solid curve shows XES data from the same sample, which provides complementary information about the occupied valence band states. Although the spectral features are broader in fully amorphous films than in nanocrystalline samples, a well-defined band gap exists in both cases with magnitude similar to that of crystalline GaN. There are additional feature

  7. Absorption phenomenon study of low energies gamma rays in the Eurogam detector STACK

    International Nuclear Information System (INIS)

    Wei, L.; Duchene, G.; Beck, F.A.; Curien, D.; France, G. de; Moszynski, M.; Santos, D.

    1991-05-01

    The composite 4 π γ detector STACK is made of a pile of Ge Crystals in which the 2 circular surfaces are active, one implanted with Boron, the other diffused with Lithium and introducing a dead zone. The goal of this study is to research the dead zones and to study their influence upon the detection efficiency [fr

  8. STUDIES AND RESEARCHES ON TYPHA LATIFOLIA’S (BULRUSH ABSORPTION CAPACITY OF HEAVY METALS FROM THE SOIL

    Directory of Open Access Journals (Sweden)

    ALEXANDRA-DANA CHIŢIMUŞ 1*, CRISTIAN RADU 1, 2, VALENTIN NEDEFF 1, EMILIAN MOŞNEGUŢU 1, NARCIS BÂRSAN 1

    2016-12-01

    Full Text Available The research aimed to determine Typha latifolia’s (bulrush absorption capacity of heavy metals from the soil in the industrial area of Piatra Neamt city, Romania. Heavy metals present in ecological systems are available to the absorption process only partially, depending on the type of pH of the environment, their chemical composition, and the quantity of heavy metals in the soil, plants, sediments, water, or air. The choice of sampling points (the industrial area of Piatra Neamt city took into consideration the areas where the pollution sources are located and where the sediment layer is thick and the granularity level is lower than 63 μm. The investigation of Typha latifolia’s absorption capacity showed that, in case of nickel, chromium, copper and arsenic, a very low capacity of heavy metals absorption was detected. Typha latifolia’s highest absorption capacity of heavy metals from the soil was recorded in case of cadmium.

  9. X-ray Absorption Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Yano, Junko; Yachandra, Vittal K.

    2009-07-09

    This review gives a brief description of the theory and application of X-ray absorption spectroscopy, both X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), especially, pertaining to photosynthesis. The advantages and limitations of the methods are discussed. Recent advances in extended EXAFS and polarized EXAFS using oriented membranes and single crystals are explained. Developments in theory in understanding the XANES spectra are described. The application of X-ray absorption spectroscopy to the study of the Mn4Ca cluster in Photosystem II is presented.

  10. Variational finite element method to study the absorption rate of drug ...

    African Journals Online (AJOL)

    M.A. Khanday

    2014-11-25

    Nov 25, 2014 ... Abstract Background: The delivery of drugs through dermal layers known as transdermal ... number of factors which includes the physio-co-chemical prop- ..... 9. Kumari B, Adlakha N. One dimensional model to study the effect.

  11. Absorptive capacity and ICT adoption strategies for SMEs: a Case study in Kenya

    CSIR Research Space (South Africa)

    Ndiege, JRA

    2014-10-01

    Full Text Available Many small and medium enterprises (SMEs) in developing countries continue to be challenged by their information technology (IT) adoption process, which is often characterized by a number of deficiencies. The purpose of this study was to examine...

  12. Variational finite element method to study the absorption rate of drug ...

    African Journals Online (AJOL)

    M.A. Khanday

    2014-11-25

    Nov 25, 2014 ... ematical transport models describing the release of drug from various delivery systems and ... numerical simulations to describe the pharmacokinetics of ... studied the diffusion of heat and mass in biological tissues particularly ...

  13. Study of hyperon-pion resonances from kaonic absorption with KLOE

    Directory of Open Access Journals (Sweden)

    Vázquez Doce Oton

    2015-01-01

    The study of the antiK-hadron interactions inside the drift chamber of KLOE was initiated in order to search for signals from the formation of deeply bound kaonic nuclear states and the study of resonances like the Λ(1405 and the Σ(1385, and constitute a first step towards the preparation of the AMADEUS experiment at DAFNE, the e+e− collider of the Frascati National Laboratories (Italy of INFN.

  14. Utilizing Near-IR Tunable Laser Absorption Spectroscopy to Study Detonation and Combustion Systems

    Science.gov (United States)

    2014-03-27

    A Hencken burner, Rotating Detonation Engine ( RDE ), and a detonation tube were studied using a Time-Devision Multiplexed Tunable Diode Laser...for the three systems. Velocity was calculated for the RDE system using the Doppler shift of the spectral lines. To perform the calculations necessary...however, the CH4 flame did not match as well. The exhaust of the RDE was studied at various equivalence ratios using a hydrogen-air mixture (H2-air

  15. Shock Tube/Laser Absorption Studies of Jet Fuels at Low Temperatures (600-1200K)

    Science.gov (United States)

    2013-08-27

    Davidson, Ronald K. Hanson. A second-generation aerosol shock tube and its use in studying ignition delay times of large biodiesel surrogates, 28th... Biodiesel Surrogate behind Reflected Shock Waves,” 8th US National Combustion Meeting, Paper 070RK-0008 Park City, UT 5/2013.   These  studies provide...www.elsevier .com/locate / fuel 1. Introduction Normal alkanes have been widely used as fuels and are major components of many commercial transportation fuels

  16. Electronic absorption spectral studies of Pr(III) chelates with some amino acids

    Science.gov (United States)

    Kachhawa, Chanchal; Solanki, Kanika; Bhandari, H. S.

    2018-05-01

    Investigations on Pr(III) systems with 1:1 metal-ligand stoichiometric ratio have been carried out in different solvents. β - Alanine, Taurine and anthranilic acid have been opted as ligands for the investigations. The Study is based on doped crystal phenomenon. The Slater-Condon, spin-orbit, nephelauxetic, bonding, Racah and Judd-Ofelt parameters have been explored during the study. Four bands for Pr(III) have been observed and recorded in the region 350 nm to 900nm. Partial regression method has been used for calculations. Use of computational chemistry has been explored in order to develop better and easier methods of calculations.

  17. Infrared absorption study of ammonium uranates and uranium oxide powders formed during their thermal decomposition

    International Nuclear Information System (INIS)

    Rofail, N.H.; ELfekey, S.A.

    1992-01-01

    Ammonium uranates (AU) were precipitated from a nuclear-pure uranyl nitrate solution using different precipitating agents. IR spectra of the obtained uranates and oxides formed during their thermal decomposition have been studied. The results indicated that the precipitating agent, mode of stirring, washing and calcining temperature are important factors for a specific oxide formation.4 FIG., 3 TAB

  18. An Inexpensive High Pressure Optical Absorption Cell for IR-VIS-UV Studies.

    Science.gov (United States)

    Rodgers, V. E.; Angell, C. A.

    1983-01-01

    Describes an optical cell, suitable for high-pressure studies between at least -130 and +150 degrees Celsius, which may be assembled for about $50. Discusses experimental demonstration of principles involved when using the apparatus, including effects of pressure on coordination of ions in solution and on reaction rates in solution. (JN)

  19. X-ray absorption spectroscopy: EXAFS and XANES - A versatile tool to study the atomic and electronic structure of materials

    International Nuclear Information System (INIS)

    Alp, E.E.; Mini, S.M.; Ramanathan, M.

    1990-01-01

    X-ray absorption spectroscopy (XAS) had been an essential tool to gather spectroscopic information about atomic energy level structure in the early decades of this century. The correct interpretation of the oscillatory structure in the x-ray absorption cross-section above the absorption edge has transformed XAS from a spectroscopic tool to a structural technique. EXAFS (Extended X-ray Absorption Fine Structure) yields information about the interatomic distances, near neighbor coordination numbers, and lattice dynamics. XANES (X-ray Absorption Near Edge Structure), on the other hand, gives information about the valence state, energy bandwidth and bond angles. Today, there are about 50 experimental stations in various synchrotrons around the world dedicated to collecting x-ray absorption data from the bulk and surfaces of solids and liquids. In this chapter, they will give the basic principles of XAS, explain the information content of essentially two different aspects of the absorption process leading to EXAFS and XANES, and discuss the source and sample limitations

  20. A theoretical study of microwave beam absorption by a rectenna, introduction. [solar power satellites

    Science.gov (United States)

    1981-01-01

    The conditions required for a large rectenna array (i.e., reference design) to absorb nearly 100% of transmitted energy were studied. Design parameters including element spacing, and the manner in which these affect scatter were formulated. Amplitudes and directions of scatter and development of strategies for mitigation were also investigated. The effects on rectenna behavior of external factors such as weather and aircraft overflights were determined.

  1. X-ray absorption spectroscopic studies on novel microporous copper containing catalytic systems

    International Nuclear Information System (INIS)

    Bhargava, Suresh K.; Akolekar, Deepak B.; Foran, Garry

    2006-01-01

    Novel copper metal modified microporous aluminosilicate and aluminophosphate catalysts with the high phase purity were synthesized and characterized. CuK-edge XAS measurements were carried out over a series of copper containing SAPO-34 and ZSM-5 catalysts. EXAFS technique was used to obtain specific climacteric information related to the copper atomic distances, coordination and near neighbour environments. EXAFS studies indicated the presence of different of Cu species on ZSM-5/SAPO34 catalysts

  2. Recombination properties of diode structures by study of thermal emission beyond the fundamental absorption band

    International Nuclear Information System (INIS)

    Piotrowski, T; Wȩgrzecki, M; Czerwinski, A; Teslenko, G I; Malyutenko, O Y; Malyutenko, V K

    2014-01-01

    The study presents the possibilities of applying the measurement of spatial and temporal distribution of thermal radiation of a p-n junction structure located in a homogeneous temperature field higher than the ambient temperature, modulated by the presence of excess carriers injected through the junction, to determine surface recombination velocity at the injecting contact of the diode emitter and to measure the diffusion length in the base. Good agreement was obtained between the experimental results and calculations based on solutions of the transport equations.

  3. Infrared Absorption Spectroscopic Study on Reaction between Self-Assembled Monolayers and Atmospheric-Pressure Plasma

    Directory of Open Access Journals (Sweden)

    Masanori Shinohara

    2015-01-01

    Full Text Available Plasma is becoming increasingly adopted in bioapplications such as plasma medicine and agriculture. This study investigates the interaction between plasma and molecules in living tissues, focusing on plasma-protein interactions. To this end, the reaction of air-pressure air plasma with NH2-terminated self-assembled monolayer is investigated by infrared spectroscopy in multiple internal reflection geometry. The atmospheric-pressure plasma decomposed the NH2 components, the characteristic units of proteins. The decomposition is attributed to water clusters generated in the plasma, indicating that protein decomposition by plasma requires humid air.

  4. Numerical study of hydrogen absorption in a LM-Ni5 hybride reactor

    International Nuclear Information System (INIS)

    Altinisik, K.; Tekin, M.; Mat, M. D.; Altinisik, A.; Veziroglu, T. N.

    2007-01-01

    Metal hydride formation in an Lm-Ni5 storage tank is numerically studied with a continuum mathematical model. The model considers complex heat, and mass transfer and chemical reaction in the reaction bed. It is found that hydride formation enhances at regions with lower equilibrium pressure. Absorbed hydrogen mass increases exponentially at earlier times of hydriding process and slow down after temperature of reaction bed increases due to the heat of reaction. Numerical results agree satisfactorily with the experimental data in the literature

  5. Chlorophyll bleaching by UV-irradiation in vitro and in situ: Absorption and fluorescence studies

    International Nuclear Information System (INIS)

    Zvezdanovic, Jelena; Cvetic, Tijana; Veljovic-Jovanovic, Sonja; Markovic, Dejan

    2009-01-01

    Chlorophyll bleaching by UV-irradiation has been studied by absorbance and fluorescence spectroscopy in extracts containing mixtures of photosynthetic pigments, in acetone and n-hexane solutions, and in aqueous thylakoid suspensions. Chlorophyll undergoes destruction (bleaching) accompanied by fluorescent transient formation obeying first-order kinetics. The bleaching is governed by UV-photon energy input, as well as by different chlorophyll molecular organizations in solvents of different polarities (in vitro), and in thylakoids (in situ). UV-C-induced bleaching of chlorophylls in thylakoids is probably caused by different mechanisms compared to UV-A- and UV-B-induced bleaching

  6. Experimental study of nitrogen oxide absorption by a liquid nitrogen tetroxide flow

    International Nuclear Information System (INIS)

    Verzhinskaya, A.B.; Saskovets, V.V.; Borovik, T.F.

    1984-01-01

    The system of N 2 O 4 based coolant regeneration needs productive and efficient absorbers, providing effective production of nitrogen oxide, decreasing upon NPP operation at the expense of radiation-thermal decomposition. The experimental istallation flowsheet for studying the nitrogen oxide absorbtion by liquid nitrogen tetroxide is given. The experiments have been carried out in removable test sections, looked like helical tubes with internal steam-and-liquid mixture flow and external water cooling. Six test sections with variable geometry factors have been manufactured. The plotted results of the experiments are given as dependences of extraction level and mass transfer volumetric coefficients on the geometry factor, pressure and Froude number

  7. Study on heavy metal absorption capability of chlamidomonas reinhardtii in solution containing uranium and lead

    International Nuclear Information System (INIS)

    Nguyen Thuy Binh

    2003-01-01

    The mutant strain chlamydomonas reinhardtii No.4 obtained by C 5+ ion beam irradiation could be grown in simple mineral salt medium with initial pH range of 3.5-7.5 with continued illumination of 12,000 lux under aeration. The study demonstrated that the mutant strain C.reinhardtii had a good growth in mineral salt medium containing U 6+ (concentration about 0.015 mg/ml) and Pb 2+ (concentration about 65% and Pb 2+ about 60% from solution was estimated by analyzing dried cell. (NTB)

  8. Small intestinal absorption in patients with chronic obstructive pulmonary disease complicated by cor pulmonale - A pilot study

    DEFF Research Database (Denmark)

    Andersen, Sara Korsgaard; Hardis, Anne L S; Tupper, Oliver Djurhuus

    2018-01-01

    BACKGROUND: Cor pulmonale is a common complication to Chronic Obstructive Pulmonary Disease (COPD), and may result in increased pressure in the inferior caval vein and stasis of the liver. The chronic pulmonary hypertension may lead to stasis in the veins from the small intestine and thereby...... compromise absorption of nutrients. AIM: To investigate whether patients with pulmonary hypertension have reduced absorption capacity compared to COPD patients without cor pulmonale. METHODS: Absorption of d-xylose (25 g) and zinc (132 mg), administered as a single dose, was tested in 14 COPD patients, seven...

  9. Study of the pressing operation of large-sized tiles using X-ray absorption

    International Nuclear Information System (INIS)

    Amoros, J. L.; Mallol, G.; Llorens, D.; Boix, J.; Arnau, J. M.; Feliu, C.; Cerisuelo, J. A.; Gargallo, J. J.

    2010-01-01

    An apparatus for X-Ray non destructive inspection of bulk density distribution in large ceramic tiles has been designed, built and patented. This technique has many advantages compared with other methods: it allows tile bulk density distribution to be mapped and is neither destructive nor toxic, provided the X-ray tube and detector area are shielded to prevent leakage. In the present study, this technique, whose technical feasibility and accuracy had been verified in previous studies, has been used to scan ceramic tiles formed under different industrial conditions, modifying press working parameters. The use of high-precision laser telemeters allows tile thicknesses to be mapped, facilitating the interpretation of manufacturing defects produced in pressing, which cannot be interpreted by just measuring bulk density. The bulk density distributions obtained in the same unfired and fired tiles are also compared, a possibility afforded only by this measurement method, since it is non-destructive. The comparison of both unfired and fired tile bulk density distributions allows the influence of the pressing and firing stages on tile end porosity to be individually identified. (Author) 12 refs.

  10. Field emission study of ammonia absorption and catalytic decomposition on individual molybdenum planes

    International Nuclear Information System (INIS)

    Abon, M.; Bergeret, G.; Tardy, B.

    1977-01-01

    A probe-hole field emission microscope was used to investigate the crystallographic specificity of ammonia adsorption at 200 and 300 K on (110), (100), (211) and (111) molybdenum crystal planes. Chemisorbed NH 3 causes a large work function decrease, especially at 200 K in agreement with an associative adsorption model which can also explain that this decrease is more important on the crystal planes of highest work function (At 200 K, Δpsi = -2.25 eV on Mo(110) compared to Δpsi = -1.55 eV on Mo(111). The decomposition of NH 3 was followed by measuring the work function changes for stepwise heating of the Mo tip covered with NH 3 at 200 K. On the four studied planes NH 3 decomposition and H 2 desorption are completed at about 400 K. Δpsi changes above 400 K depend on the crystal planes and have been related to two different nitrogen surface states. No inactive plane towards NH 3 adsorption and decomposition has been found but the noted crystallographic anisotropy in this low pressure study is relevant to the structure sensitive character of the NH 3 decomposition and synthesis reactions. (Auth.)

  11. Temperature dependent evolution of the local electronic structure of atmospheric plasma treated carbon nanotubes: Near edge x-ray absorption fine structure study

    International Nuclear Information System (INIS)

    Roy, S. S.; Papakonstantinou, P.; Okpalugo, T. I. T.; Murphy, H.

    2006-01-01

    Near edge x-ray absorption fine structure (NEXAFS) spectroscopy has been employed to obtain the temperature dependent evolution of the electronic structure of acid treated carbon nanotubes, which were further modified by dielectric barrier discharge plasma processing in an ammonia atmosphere. The NEXAFS studies were performed from room temperature up to 900 deg. C. The presence of oxygen and nitrogen containing functional groups was observed in C K edge, N K edge, and O K edge NEXAFS spectra of the multiwalled carbon nanotubes. The N K edge spectra revealed three types of π* features, the source of which was decisively identified by their temperature dependent evolution. It was established that these features are attributed to pyridinelike, NO, and graphitelike structures, respectively. The O K edge indicated that both carbonyl (C=O), π*(CO), and ether C-O-C, σ*(CO), functionalities were present. Upon heating in a vacuum to 900 deg. C the π*(CO) resonances disappeared while the σ*(CO) resonances were still present confirming their higher thermal stability. Heating did not produce a significant change in the π* feature of the C K edge spectrum indicating that the tabular structure of the nanotubes is essentially preserved following the thermal decomposition of the functional groups on the nanotube surface

  12. Designed plasmonic nanocatalysts for the reduction of eosin Y: absorption and fluorescence study

    Science.gov (United States)

    Komalam, Abha; Muraleegharan, Lekha Girija; Subburaj, Suganthi; Suseela, Suji; Babu, Aswathy; George, Sony

    2012-10-01

    In this work, we report a one-step green synthesis of gold nanoparticles (AuNPs) by microwave irradiation using nontoxic and biodegradable polysaccharide chitosan as a reducing and stabilizing agent. The interaction between gold nanoparticles with the amine group of chitosan was confirmed by Fourier transform infrared spectroscopy analysis, and the stability of the nanoparticle is ascertained by zeta potential measurements. Transmission electron microscopy photograph and dynamic light scattering measurements confirmed the average size of gold nanoparticles as 25 nm. The ability of the synthesised gold nanoparticles as a catalyst for the reduction of eosin dye in the presence of NaBH4 was monitored by means of spectrofluorometry and spectrophotometry. It is found that the NaBH4-induced reduction of eosin is enhanced in the presence of AuNPs even without a catalyst. Time-resolved fluorescence decay studies also confirmed the reduction of eosin in the presence of AuNPs.

  13. Infrared absorption study of hydrogen incorporation in thick nanocrystalline diamond films

    International Nuclear Information System (INIS)

    Tang, C.J.; Neves, A.J.; Carmo, M.C.

    2005-01-01

    We present an infrared (IR) optical absorbance study of hydrogen incorporation in nanocrystalline diamond films. The thick nanocrystalline diamond films were synthesized by microwave plasma-assisted chemical vapor deposition and a high growth rate about 3.0 μm/h was achieved. The morphology, phase quality, and hydrogen incorporation were assessed by means of scanning electron microscopy, Raman spectroscopy, and Fourier-transform infrared spectroscopy (FTIR). Large amount of hydrogen bonded to nanocrystalline diamond is clearly evidenced by the huge CH stretching band in the FTIR spectrum. The mechanism of hydrogen incorporation is discussed in light of the growth mechanism of nanocrystalline diamond. This suggests the potential of nanocrystalline diamond for IR electro-optical device applications

  14. Clinical studies of /sup 131/I labeled fat absorption test by the temporal counting

    Energy Technology Data Exchange (ETDEWEB)

    Kaneko, T [Kumamoto Univ. (Japan). School of Medicine

    1974-09-01

    After administration of the /sup 131/I-triolein capsule test meal, a temporal count curve was obtained. In all, 87 cases were studied of which twenty were normal and 67 were pathological. The time required to reach the highest value (TRHV) of the temporal count curve, 60% in chronic pancreatitis was more than 6 hours, while it took less than 5 hours in normal cases. In cases of intrathoracic esophagogastrostomy and hypothyroidism, TRHV was longer than the normal value. In cases of radiation therapy, TRHV was prolongated with the increase of the radiation dose. Correlation coefficient between TRHV and fecal radioactivity levels (% of dose) was investigated for each patient and was found to be significant.

  15. Experimental study of nitrogen oxide absorption by a liquid nitrogen tetroxide flow

    Energy Technology Data Exchange (ETDEWEB)

    Verzhinskaya, A B; Saskovets, V V; Borovik, T F

    1984-01-01

    The system of N/sub 2/O/sub 4/ based coolant regeneration needs productive and efficient absorbers, providing effective production of nitrogen oxide, decreasing upon NPP operation at the expense of radiation-thermal decomposition. The experimental istallation flowsheet for studying the nitrogen oxide absorbtion by liquid nitrogen tetroxide is given. The experiments have been carried out in removable test sections, looked like helical tubes with internal steam-and-liquid mixture flow and external water cooling. Six test sections with variable geometry factors have been manufactured. The plotted results of the experiments are given as dependences of extraction level and mass transfer volumetric coefficients on the geometry factor, pressure and Froude number.

  16. Wave energy absorption by ducks

    OpenAIRE

    Kurniawan, Adi

    2017-01-01

    We study the absorption of wave energy by a single and multiple cam-shaped bodies referred to as ducks. Numerical models are developed under the assumptions of linear theory. We consider wave absorption by a single duck as well as by two lines of ducks meeting at an angle.

  17. Wave energy absorption by ducks

    DEFF Research Database (Denmark)

    Kurniawan, Adi

    2018-01-01

    We study the absorption of wave energy by a single and multiple cam-shaped bodies referred to as ducks. Numerical models are developed under the assumptions of linear theory. We consider wave absorption by a single duck as well as by two lines of ducks meeting at an angle....

  18. Sublinear absorption in OCS gas

    International Nuclear Information System (INIS)

    Bogani, F.; Querzoli, R.; Ernst, K.

    1988-01-01

    Sublinear absorption in OCS gas has been experimentally studied in detail by means of an optoacustic technique and transmission measurements. The best fit of the results is obtained by a phenomenological model, that considers the process as the sum of one-and two-photon absorptions

  19. Optical absorption of irradiated carbohydrates

    International Nuclear Information System (INIS)

    Supe, A.A.; Tiliks, Yu.E.

    1994-01-01

    The optical absorption spectra of γ-irradiated carbohydrates (glucose, lactose, sucrose, maltose, and starch) and their aqueous solutions were studied. The comparison of the data obtained with the determination of the concentrations of molecular and radical products of radiolysis allows the absorption bands with maxima at 250 and 310 nm to be assigned to the radicals trapped in the irradiated carbohydrates

  20. Water absorption in brick masonry

    NARCIS (Netherlands)

    Brocken, H.J.P.; Smolders, H.R.

    1996-01-01

    The water absorption in brick, mortar that was cured separately, and masonry samples was studied using NMR. Models of the moisture transport are usually formulated on the basis of a diffusion equation. In the case of water absorption in separate brick and mortar samples, the moisture diffusivity in