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Sample records for bacteriochlorophylls form concentric

  1. Quantification of two forms of green sulfur bacteria in their natural habitat using bacteriochlorophyll fluorescence spectra

    Science.gov (United States)

    Kharcheva, Anastasia V.; Zhiltsova, Anna A.; Lunina, Olga N.; Savvichev, Alexander S.; Patsaeva, Svetlana V.

    2016-04-01

    Detection of phototropic organisms in their natural habitat using optical instruments operating under water is urgently needed for many tasks of ecological monitoring. While fluorescence methods are widely applied nowadays to detect and characterize phytoplankton communities, the techniques for detection and recognition of anoxygenic phototrophs are considered challenging. Differentiation of the forms of anoxygenic green sulfur bacteria in natural water using spectral techniques remains problematic. Green sulfur bacteria could be found in two forms, green-colored (containing BChl d in pigment compound) and brown-colored (containing BChl e), have the special ecological niche in such reservoirs. Separate determination of these microorganisms by spectral methods is complicated because of similarity of spectral characteristics of their pigments. We describe the novel technique of quantification of two forms of green sulfur bacteria directly in water using bacteriochlorophyll fluorescence without pigment extraction. This technique is noninvasive and could be applied in remote mode in the water bodies with restricted water circulation to determine simultaneously concentrations of two forms of green sulfur bacteria in their natural habitat.

  2. Spectral properties of bacteriochlorophyll c in nematic liquid crystal. Part 1. Monomeric forms of dye

    Science.gov (United States)

    Dudkowiak, A.; Francke, C.; Amesz, J.; Planner, A.; Hanyz, I.; Fraçkowiak, D.

    1996-02-01

    The spectroscopic features of bacteriochlorophyll c and bacteriopheophytin c in a nematic liquid crystal matrix have been investigated. Absorption, circular dichroism, fluorescence and time resolved delayed luminescence spectra have been measured. The pigment is introduced to the liquid crystal from a dry and from a hydrated chloroform solution. In both cases the pigment is in the monomeric form. Hydration of the solvent and the presence or absence of the central Mg atom affect the interaction of the pigment molecules with the liquid crystal matrix, changing the fluorescence anisotropy. A model for the bacteriochlorophyll c orientation in the liquid crystal is proposed and the averaged angles between the transition moments and the liquid crystal orientation axis are determined. A slow process (in the microsecond range) of radiative deactivation of energy absorbed by the pigments is observed. This delayed emission could be due to pigment ionization and delayed charge recombination and/or thermal activation from the triplet to the excited singlet state.

  3. {beta}-Carotene to bacteriochlorophyll c energy transfer in self-assembled aggregates mimicking chlorosomes

    Energy Technology Data Exchange (ETDEWEB)

    Alster, J. [Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 121 16 Praha (Czech Republic); Polivka, T. [Institute of Physical Biology, University of South Bohemia, Zamek 136, 373 33 Nove Hrady (Czech Republic); Biology Centre, Academy of Sciences of the Czech Republic, Branisovska 31, 370 05 Ceske Budejovice (Czech Republic); Arellano, J.B. [Instituto de Recursos Naturales y Agrobiologia de Salamanca (IRNASA-CSIC), Apdo. 257, 37071 Salamanca (Spain); Chabera, P. [Institute of Physical Biology, University of South Bohemia, Zamek 136, 373 33 Nove Hrady (Czech Republic); Vacha, F. [Institute of Physical Biology, University of South Bohemia, Zamek 136, 373 33 Nove Hrady (Czech Republic); Biology Centre, Academy of Sciences of the Czech Republic, Branisovska 31, 370 05 Ceske Budejovice (Czech Republic); Psencik, J., E-mail: psencik@karlov.mff.cuni.cz [Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 121 16 Praha (Czech Republic); Institute of Physical Biology, University of South Bohemia, Zamek 136, 373 33 Nove Hrady (Czech Republic)

    2010-07-19

    Carotenoids are together with bacteriochlorophylls important constituents of chlorosomes, the light-harvesting antennae of green photosynthetic bacteria. Majority of bacteriochlorophyll molecules form self-assembling aggregates inside the chlorosomes. Aggregates of bacteriochlorophylls with optical properties similar to those of chlorosomes can also be prepared in non-polar organic solvents or in aqueous environments when a suitable non-polar molecule is added. In this work, the ability of {beta}-carotene to induce aggregation of bacteriochlorophyll c in aqueous buffer was studied. Excitation relaxation and energy transfer in the carotenoid-bacteriochlorophyll assemblies were measured using femtosecond and nanosecond transient absorption spectroscopy. A fast, {approx}100-fs energy transfer from the S{sub 2} state of {beta}-carotene to bacteriochlorophyll c was revealed, while no evidence for significant energy transfer from the S{sub 1} state was found. Picosecond formation of the carotenoid triplet state (T{sub 1}) was observed, which was likely generated by singlet homo-fission from the S{sub 1} state of {beta}-carotene.

  4. Origin of Bacteriochlorophyll a and the Early Diversification of Photosynthesis.

    Directory of Open Access Journals (Sweden)

    Tanai Cardona

    Full Text Available Photosynthesis originated in the domain Bacteria billions of years ago; however, the identity of the last common ancestor to all phototrophic bacteria remains undetermined and speculative. Here I present the evolution of BchF or 3-vinyl-bacteriochlorophyll hydratase, an enzyme exclusively found in bacteria capable of synthetizing bacteriochlorophyll a. I show that BchF exists in two forms originating from an early divergence, one found in the phylum Chlorobi, including its paralogue BchV, and a second form that was ancestral to the enzyme found in the remaining anoxygenic phototrophic bacteria. The phylogeny of BchF is consistent with bacteriochlorophyll a evolving in an ancestral phototrophic bacterium that lived before the radiation event that gave rise to the phylum Chloroflexi, Chlorobi, Acidobacteria, Proteobacteria, and Gemmatimonadetes, but only after the divergence of Type I and Type II reaction centers. Consequently, it is suggested that the lack of phototrophy in many groups of extant bacteria is a derived trait.

  5. IMPACT OF LIGHT DARK REGIMEN ON GROWTH-RATE, BIOMASS FORMATION AND BACTERIOCHLOROPHYLL SYNTHESIS IN ERYTHROMICROBIUM-HYDROLYTICUM

    NARCIS (Netherlands)

    YURKOV, VV; VANGEMERDEN, H

    1993-01-01

    The impact of illumination on specific growth rate, biomass formation, and synthesis of photopigment was studied in Erythromicrobium hydrolyticum, an obligately aerobic heterotrophic bacterium having the ability to synthesize bacteriochlorophyll a. In dark-grown continuous cultures the concentration

  6. Ultrafast intramolecular relaxation dynamics of Mg- and Zn-bacteriochlorophyll a

    International Nuclear Information System (INIS)

    Ultrafast excited-state dynamics of the photosynthetic pigment (Mg-)bacteriochlorophyll a and its Zn-substituted form were investigated by steady-state absorption/fluorescence and femtosecond pump-probe spectroscopic measurements. The obtained steady-state absorption and fluorescence spectra of bacteriochlorophyll a in solution showed that the central metal compound significantly affects the energy of the Qx state, but has almost no effect on the Qy state. Photo-induced absorption spectra were recorded upon excitation of Mg- and Zn-bacteriochlorophyll a into either their Qx or Qy state. By comparing the kinetic traces of transient absorption, ground-state beaching, and stimulated emission after excitation to the Qx or Qy state, we showed that the Qx state was substantially incorporated in the ultrafast excited-state dynamics of bacteriochlorophyll a. Based on these observations, the lifetime of the Qx state was determined to be 50 and 70 fs for Mg- and Zn-bacteriochlorophyll a, respectively, indicating that the lifetime was influenced by the central metal atom due to the change of the energy gap between the Qx and Qy states

  7. Optical spectroscopy of a highly fluorescent aggregate of bacteriochlorophyll c

    Science.gov (United States)

    Causgrove, T. P.; Cheng, P.; Brune, D. C.; Blankenship, R. E.

    1993-01-01

    Bacteriochlorophyll (BChl) c and a similar model compound, Mg-methyl bacteriopheophorbide d, form several types of aggregates in nonpolar solvents. One of these aggregates is highly fluorescent, with a quantum yield higher than that of the monomer. This aggregate is also unusual in that it shows a rise time in its fluorescence emission decay at certain wavelengths, which is ascribed to a change in conformation of the aggregate. An analysis of fluorescence depolarization data is consistent with either a linear aggregate of four or five monomers or preferably a cyclic arrangement of three dimers.

  8. Circular dichroism study on the diastereoselective self-assembly of bacteriochlorophyll cs

    Science.gov (United States)

    Balaban, Teodor S.; Holzwarth, Alfred R.; Schaffner, Kurt

    1995-04-01

    Circular dichroism (CD) spectra of self-assembled bacteriochlorophyll cs (BChl cs) aggregates show a pronounced dependency on the solvent, the concentration and on the stereochemistry of the 3 1-hydroxy groups. In n-hexane a psi-type CD is obtained due to the formation of nanostructural aggregates.

  9. Benchmarking calculations of excitonic couplings between bacteriochlorophylls

    CERN Document Server

    Kenny, Elise P

    2015-01-01

    Excitonic couplings between (bacterio)chlorophyll molecules are necessary for simulating energy transport in photosynthetic complexes. Many techniques for calculating the couplings are in use, from the simple (but inaccurate) point-dipole approximation to fully quantum-chemical methods. We compared several approximations to determine their range of applicability, noting that the propagation of experimental uncertainties poses a fundamental limit on the achievable accuracy. In particular, the uncertainty in crystallographic coordinates yields an uncertainty of about 20% in the calculated couplings. Because quantum-chemical corrections are smaller than 20% in most biologically relevant cases, their considerable computational cost is rarely justified. We therefore recommend the electrostatic TrEsp method across the entire range of molecular separations and orientations because its cost is minimal and it generally agrees with quantum-chemical calculations to better than the geometric uncertainty. We also caution ...

  10. Probing the bacteriochlorophyll binding site by reconstitution of the light-harvesting complex of Rhodospirillum rubrum with bacteriochlorophyll a analogues

    International Nuclear Information System (INIS)

    Structural features of bacteriochlorophyll (BChl) a that are required for binding to the light-harvesting proteins of Rhodospirillum rubrum were determined by testing for reconstitution of the B873 or B820 (structural subunit of B873) light-harvesting complexes with BChl a analogues. The results indicate that the binding site is very specific; of the analogues tested, only derivatives of BChl a with ethyl, phytyl, and geranylgeranyl esterifying alcohols and BChl b (phytyl) successfully reconstituted to form B820-and B873-type complexes. BChl analogues lacking magnesium, the C-3 acetyl group, or the C132 carbomethoxy group did not reconstitute to form B820 or B873. Also unreactive were 132-hydroxy BChl a and 3-acetylchlorophyll a. Competition experiments showed that several of these nonreconstituting analogues significantly slowed BChl a binding to form B820 and blocked BChl a-B873 formation, indicating that the analogues may competitively bind to the protein even though they do not form red-shifted complexes. With the R. rubrum polypeptides, BChl b formed complexes that were further red-shifted than those of BChl a; however, the energies of the red shifts, binding behavior, and circular dichroism (CD) spectra were similar. B873 complexes reconstituted with the geranylgeranyl BChl a derivative, which contains the native esterifying alcohol for R. rubrum, showed in-vivo-like CD features, but the phytyl and ethyl B873 complexes showed inverted CD features in the near infrared. The B820 complex with the ethyl derivative was about 30-fold less stable than the two longer esterifying alcohol derivatives, but all formed stable B873 complexes

  11. Beam-Forming Concentrating Solar Thermal Array Power Systems

    Science.gov (United States)

    Cwik, Thomas A. (Inventor); Dimotakis, Paul E. (Inventor); Hoppe, Daniel J. (Inventor)

    2016-01-01

    The present invention relates to concentrating solar-power systems and, more particularly, beam-forming concentrating solar thermal array power systems. A solar thermal array power system is provided, including a plurality of solar concentrators arranged in pods. Each solar concentrator includes a solar collector, one or more beam-forming elements, and one or more beam-steering elements. The solar collector is dimensioned to collect and divert incoming rays of sunlight. The beam-forming elements intercept the diverted rays of sunlight, and are shaped to concentrate the rays of sunlight into a beam. The steering elements are shaped, dimensioned, positioned, and/or oriented to deflect the beam toward a beam output path. The beams from the concentrators are converted to heat at a receiver, and the heat may be temporarily stored or directly used to generate electricity.

  12. Direct observation of monomer film structure of bacteriochlorophyll c

    Institute of Scientific and Technical Information of China (English)

    JIANG Yaxin; XU Qingmin; WAN Lijun; WANG Chen; FANG Xiaohong; BAI Chunli; WANG Zhengyu; Nozawa Tsunenori

    2003-01-01

    The adsorption and assembling of bacteriochlorophyll c (BChl c) on a highly oriented pyrolytic graphite (HOPG) surface have been investigated by the scanning tunneling microscopy (STM). BChl c molecules are found to self-organize a well-defined adlayer on HOPG surface with a monomeric structure different fromthe dimer association seen on adlayers of Chls a, c and BChlide c, d. A structural model is proposed for the adlayer.

  13. Separation of bacteriochlorophyll homologues from green photosynthetic sulfur bacteria by reversed-phase HPLC.

    Science.gov (United States)

    Borrego, C M; Garcia-Gil, L J

    1994-07-01

    A reversed-phase High Performance Liquid Cromatography (HPLC) method has been developed to accurately separate bacteriochlorophyllsc, d ande homologues in a reasonably short run time of 60 minutes. By using this method, two well-defined groups of bacteriochlorophyll homologue peaks can be discriminated. The first one consists of 4 peaks (min 24 to 30), which corresponds to the four main farnesyl homologues. The second peak subset is formed by a cluster of up to 10 minor peaks (min 33 to 40). These peaks can be related with series of several alcohol esters of the different chlorosome chlorophylls. The number of homologues was, however, quite variable depending on both, the bacteriochlorophyll and the bacterial species. The method hereby described, also provides a good separation of other photosynthetic pigments, either bacterial (Bacteriochlorophylla, chlorobactene, isorenieratene and okenone) or algal ones (Chlorophylla, Pheophytina and β-carotene). A preliminary screening of the homologue composition of several green photosynthetic bacterial species and isolates, has revealed different relative quantitative patterns. These differences seem to be related to physiological aspects rather than to taxonomic ones. The application of the method to the study of natural populations avoids the typical drawbacks on the pigment identification of overlapping eukaryotic and prokaryotic phototrophic microorganisms, giving further information about their physiological status. PMID:24310022

  14. Energy transfer in aggregates of bacteriochlorophyll c self-assembled with azulene derivatives.

    Science.gov (United States)

    Matěnová, Martina; Lorelei Horhoiu, Viviana; Dang, Florian-Xuan; Pospíšil, Petr; Alster, Jan; Burda, Jaroslav V; Balaban, Teodor Silviu; Pšenčík, Jakub

    2014-08-21

    Bacteriochlorophyll (BChl) c is the main light-harvesting pigment of certain photosynthetic bacteria. It is found in the form of self-assembled aggregates in the so-called chlorosomes. Here we report the results of co-aggregation experiments of BChl c with azulene and its tailored derivatives. We have performed spectroscopic and quantum chemical characterization of the azulenes, followed by self-assembly experiments. The results show that only azulenes with sufficient hydrophobicity are able to induce aggregation of BChl c. Interestingly, only azulene derivatives possessing a conjugated phenyl ring were capable of efficient (∼50%) excitation energy transfer to BChl molecules. These aggregates represent an artificial light-harvesting complex with enhanced absorption between 220 and 350 nm compared to aggregates of pure BChl c. The results provide insight into the principles of self-assembly of BChl aggregates and suggest an important role of the π-π interactions in efficient energy transfer. PMID:24999619

  15. Free-formed insulated concentrating solar collector. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Goodwin, G.

    1981-01-01

    A free-formed, insulated solar concentrating-collector was designed, built, and tested. The design utilizes new concepts to achieve simplicity, low cost, high efficiency, and long service life. Three concepts were utilized to meet these goals: First, the concentrating reflector is free-formed by hand from a thin steel sheet. Second, a transparent cover is placed over the concentrator and insulation is placed on the back and ends reduce heat losses and protect the reflecting surface from attack by rain and dust. Third, a highly-reflective aluminum film, protected by bonding between two thin sheets of uv stabilized polyester, is fastened to the steel substrate by peelable adhesive. The material cost of the unit without sun seeking electronics and drive motor is about $6.75 per square foot of sun capturing area. Sun following equipment adds to the cost, however, in units of about 100 square feet sun following equipment contributes about $2.00 per square foot. Labor costs are estimated to be approximately $3.00 per square foot for a $5.00 per hour labor rate for a trained crew. On a do-it-yourself basis a 100 square foot unit would cost about $875. Tests of the prototype collector performed by a certified solar test laboratory were made and the results compared with similar tests of a commercial unit. These tests indicate that the efficiency of the prototype is higher than the commercial unit at outlet temperatures below 160/sup 0/F and comparable with the commercial unit at the boiling point of water.

  16. Effect of carotenoids and monogalactosyl diglyceride on bacteriochlorophyll c aggregates in aqueous buffer: implications for the self-assembly of chlorosomes.

    Science.gov (United States)

    Klinger, Pavel; Arellano, Juan B; Vácha, Frantisek; Hála, Jan; Psencík, Jakub

    2004-01-01

    Aggregation of bacteriochlorophyll (BChl) c from chlorosomes, the main light-harvesting complex of green bacteria, has been studied in aqueous buffer. Unlike other chlorophyll-like molecules, BChl c is rather soluble in aqueous buffer, forming dimers. When BChl c is mixed with carotenoids (Car), the BChl c Qy transition is further redshifted, in respect to that of monomers and dimers. The results suggest that Car are incorporated in the aggregates and induce further aggregation of BChl c. The redshift of the BChl c Qy band is proportional to the Car concentration. In contrast, the mixture of bacteriochlorophyllide (BChlide) c, which lacks the nonpolar esterifying alcohol, does not form aggregates with Car in aqueous buffer or nonpolar solvents. Instead, the position of the BChlide c Qy transition remains unshifted in respect to that of the monomeric molecule, and Car precipitates with the course of time in aqueous buffer. Similar effects on both BChl c and BChlide c are also observed when monogalactosyl diglyceride (MGDG), which forms the monolayer envelope of chlorosomes, is used instead of (or together with) Car. The results show that the hydrophobic interactions of the BChl c esterifying alcohols with themselves and the nonpolar carbon skeleton of Car, or the fatty acid tails of MGDG, are essential driving forces for BChl aggregation in chlorosomes. PMID:15623345

  17. Effect of Carotenoids and Monogalactosyl Diglyceride on Bacteriochlorophyll c Aggregates in Aqueous Buffer: Implications for the Self-assembly of Chlorosomes

    OpenAIRE

    Klinger, Pavel; Arellano, Juan B.; Vácha, Frantisek; Hála, Jan; Psencik, Jakub

    2004-01-01

    Aggregation of bacteriochlorophyll (BChl) c from chlorosomes, the main light-harvesting complex of green bacteria, has been studied in aqueous buffer. Unlike other chlorophyll-like molecules, BChl c is rather soluble in aqueous buffer, forming dimers. When BChl c is mixed with carotenoids (Car), the BChl c Qy transition is further redshifted, in respect to that of monomers and dimers. The results suggest that Car are incorporated in the aggregates and induce further aggregation of BChl c. The...

  18. Quenching of bacteriochlorophyll fluorescence in chlorosomes from Chloroflexus aurantiacus by exogenous quinones

    DEFF Research Database (Denmark)

    Tokita, S; Frigaard, N-U; Hirota, M;

    2000-01-01

    The quenching of bacteriochlorophyll (BChl) c fluorescence in chlorosomes isolated from Chloroflexus aurantiacus was examined by the addition of various benzoquinones, naphthoquinones (NQ), and anthraquinones (AQ). Many quinones showed strong quenching in the micromolar or submicromolar range. Th...

  19. Spectral heterogeneity and carotenoid-to-bacteriochlorophyll energy transfer in LH2 light-harvesting complexes from Allochromatium vinosum.

    Science.gov (United States)

    Magdaong, Nikki M; LaFountain, Amy M; Hacking, Kirsty; Niedzwiedzki, Dariusz M; Gibson, George N; Cogdell, Richard J; Frank, Harry A

    2016-02-01

    Photosynthetic organisms produce a vast array of spectral forms of antenna pigment-protein complexes to harvest solar energy and also to adapt to growth under the variable environmental conditions of light intensity, temperature, and nutrient availability. This behavior is exemplified by Allochromatium (Alc.) vinosum, a photosynthetic purple sulfur bacterium that produces different types of LH2 light-harvesting complexes in response to variations in growth conditions. In the present work, three different spectral forms of LH2 from Alc. vinosum, B800-820, B800-840, and B800-850, were isolated, purified, and examined using steady-state absorption and fluorescence spectroscopy, and ultrafast time-resolved absorption spectroscopy. The pigment composition of the LH2 complexes was analyzed by high-performance liquid chromatography, and all were found to contain five carotenoids: lycopene, anhydrorhodovibrin, spirilloxanthin, rhodopin, and rhodovibrin. Spectral reconstructions of the absorption and fluorescence excitation spectra based on the pigment composition revealed significantly more spectral heterogeneity in these systems compared to LH2 complexes isolated from other species of purple bacteria. The data also revealed the individual carotenoid-to-bacteriochlorophyll energy transfer efficiencies which were correlated with the kinetic data from the ultrafast transient absorption spectroscopic experiments. This series of LH2 complexes allows a systematic exploration of the factors that determine the spectral properties of the bound pigments and control the rate and efficiency of carotenoid-to-bacteriochlorophyll energy transfer.

  20. Spectral heterogeneity and carotenoid-to-bacteriochlorophyll energy transfer in LH2 light-harvesting complexes from Allochromatium vinosum.

    Science.gov (United States)

    Magdaong, Nikki M; LaFountain, Amy M; Hacking, Kirsty; Niedzwiedzki, Dariusz M; Gibson, George N; Cogdell, Richard J; Frank, Harry A

    2016-02-01

    Photosynthetic organisms produce a vast array of spectral forms of antenna pigment-protein complexes to harvest solar energy and also to adapt to growth under the variable environmental conditions of light intensity, temperature, and nutrient availability. This behavior is exemplified by Allochromatium (Alc.) vinosum, a photosynthetic purple sulfur bacterium that produces different types of LH2 light-harvesting complexes in response to variations in growth conditions. In the present work, three different spectral forms of LH2 from Alc. vinosum, B800-820, B800-840, and B800-850, were isolated, purified, and examined using steady-state absorption and fluorescence spectroscopy, and ultrafast time-resolved absorption spectroscopy. The pigment composition of the LH2 complexes was analyzed by high-performance liquid chromatography, and all were found to contain five carotenoids: lycopene, anhydrorhodovibrin, spirilloxanthin, rhodopin, and rhodovibrin. Spectral reconstructions of the absorption and fluorescence excitation spectra based on the pigment composition revealed significantly more spectral heterogeneity in these systems compared to LH2 complexes isolated from other species of purple bacteria. The data also revealed the individual carotenoid-to-bacteriochlorophyll energy transfer efficiencies which were correlated with the kinetic data from the ultrafast transient absorption spectroscopic experiments. This series of LH2 complexes allows a systematic exploration of the factors that determine the spectral properties of the bound pigments and control the rate and efficiency of carotenoid-to-bacteriochlorophyll energy transfer. PMID:26048106

  1. Simulated two-dimensional electronic spectroscopy of the eight-bacteriochlorophyll FMO complex

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, Shu-Hao [Department of Chemistry and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States); Kais, Sabre, E-mail: kais@purdue.edu [Department of Chemistry and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States); Qatar Environment and Energy Research Institute, Qatar Foundation, Doha (Qatar)

    2014-12-21

    The Fenna-Matthews-Olson (FMO) protein-pigment complex acts as a molecular wire conducting energy between the outer antenna system and the reaction center; it is an important photosynthetic system to study the transfer of excitonic energy. Recent crystallographic studies report the existence of an additional (eighth) bacteriochlorophyll a (BChl a) in some of the FMO monomers. To understand the functionality of this eighth BChl, we simulated the two-dimensional electronic spectra of both the 7-site (apo form) and the 8-site (holo form) variant of the FMO complex from green sulfur bacteria, Prosthecochloris aestuarii. By comparing the spectrum, it was found that the eighth BChl can affect two different excitonic energy transfer pathways: (1) it is directly involved in the first apo form pathway (6 → 3 → 1) by passing the excitonic energy to exciton 6; and (2) it facilitates an increase in the excitonic wave function overlap between excitons 4 and 5 in the second pathway (7 → 4,5 → 2 → 1) and thus increases the possible downward sampling routes across the BChls.

  2. The supramolecular organization of self-assembling chlorosomal bacteriochlorophyll c, d, or e mimics.

    Science.gov (United States)

    Jochum, Tobias; Reddy, Chilla Malla; Eichhöfer, Andreas; Buth, Gernot; Szmytkowski, Jedrzej; Kalt, Heinz; Moss, David; Balaban, Teodor Silviu

    2008-09-01

    Bacteriochlorophylls (BChls) c, d, and e are the main light-harvesting pigments of green photosynthetic bacteria that self-assemble into nanostructures within the chlorosomes forming the most efficient antennas of photosynthetic organisms. All previous models of the chlorosomal antennae, which are quite controversially discussed because no single crystals could be grown so far from these organelles, involve a strong hydrogen-bonding interaction between the 3(1) hydroxyl group and the 13(1) carbonyl group. We have synthesized different self-assemblies of BChl c mimics having the same functional groups as the natural counterparts, that is, a hydroxyethyl substituent, a carbonyl group and a divalent metal atom ligated by a tetrapyrrole. These artificial BChl mimics have been shown by single crystal x-ray diffraction to form extended stacks that are packed by hydrophobic interactions and in the absence of hydrogen bonding. Time-resolved photoluminescence proves the ordered nature of the self-assembled stacks. FT-IR spectra show that on self-assembly the carbonyl frequency is shifted by approximately 30 cm(-1) to lower wavenumbers. From the FT-IR data we can infer the proximal interactions between the BChls in the chlorosomes consistent with a single crystal x-ray structure that shows a weak electrostatic interaction between carbonyl groups and the central zinc atom. PMID:18755898

  3. Regulation of carotenoid and bacteriochlorophyll biosynthesis genes and identification of an evolutionarily conserved gene required for bacteriochlorophyll accumulation.

    Science.gov (United States)

    Armstrong, G A; Cook, D N; Ma, D; Alberti, M; Burke, D H; Hearst, J E

    1993-05-01

    The temporal expression of ten clustered genes required for carotenoid (crt) and bacteriochlorophyll (bch) biosynthesis was examined during the transition from aerobic respiration to anaerobiosis requisite for the development of the photosynthetic membrane in the bacterium Rhodobacter capsulatus. Accumulation of crtA, crtC, crtD, crtE, crtF, crtK, bchC and bchD mRNAs increased transiently and coordinately, up to 12-fold following removal of oxygen from the growth medium, paralleling increases in mRNAs encoding pigment-binding polypeptides of the photosynthetic apparatus. The crtB and crtI genes, in contrast, were expressed similarly in the presence or absence of oxygen. The regulation patterns of promoters for the crtA and crtI genes and the bchCXYZ operon were characterized using lacZ transcriptional fusion and qualitatively reflected the corresponding mRNA accumulation patterns. We also report that the bchI gene product, encoded by a DNA sequence previously considered to be a portion of crtA, shares 49% sequence identity with the nuclear-encoded Arabidopsis thaliana Cs chloroplast protein required for normal pigmentation in plants.

  4. Bacteriochlorophyll f: properties of chlorosomes containing the "forbidden chlorophyll"

    Directory of Open Access Journals (Sweden)

    Kajetan eVogl

    2012-08-01

    Full Text Available The chlorosomes of green sulfur bacteria are mainly assembled from one of three types of bacteriochlorophylls, BChls c, d, and e. By analogy to the relationship between BChl c and BChl d (20-desmethyl-BChl c, a fourth type of BChl, BChl f (20-desmethyl-BChl e, should exist but has not yet been observed in nature. The bchU gene (bacteriochlorophyllide C-20 methyltransferase of the brown-colored green sulfur bacterium Chlorobaculum limnaeum was inactivated by conjugative transfer from Eshcerichia coli and homologous recombination of a suicide plasmid carrying a portion of the bchU. The resulting bchU mutant was greenish brown in color and synthesized BChl fF. The chlorosomes of the bchU mutant had similar size and polypeptide composition as those of the wild type (WT, but the Qy absorption band of the BChl f aggregates was blue-shifted 16 nm (705 nm vs. 721 nm for the WT. Fluorescence spectroscopy showed that energy transfer to the baseplate was much less efficient in chlorosomes containing BChl f than in WT chlorosomes containing BChl e. When cells were grown at high irradiance with tungsten or fluorescent light, the WT and bchU mutant had identical growth rates. However, the WT grew about 50% faster than the bchU mutant at low irradiance (10 µmol photons m-2 s-1. Less efficient energy transfer from BChl f aggregates to BChl a in the baseplate, the much slower growth of the strain producing BChl f relative to the WT, and competition from other phototrophs, may explain why BChl f is not observed naturally.

  5. Exogenous quinones inhibit photosynthetic electron transfer in Chloroflexus aurantiacus by specific quenching of the excited bacteriochlorophyll c antenna

    DEFF Research Database (Denmark)

    Frigaard, N-U; Tokita, S; Matsuura, K

    1999-01-01

    , but not when BChl a was excited. The quenching of BChl c fluorescence induced by these quinones correlated with the inhibition of flash-induced cytochrome c oxidation. We concluded that the quinones inhibited electron transfer in the reaction center by specifically quenching the excitation energy in the BChl c......-hydroxy-1,4-naphthoquinone, or 4 microM 2-acetyl-3-methyl-1,4-naphthoquinone. Between 25 and 100 times higher quinone concentrations were needed to quench BChl a fluorescence to a similar extent. These quinones also efficiently inhibited flash-induced cytochrome c oxidation when BChl c was excited......In the photosynthetic green filamentous bacterium Chloroflexus aurantiacus, excitation energy is transferred from a large bacteriochlorophyll (BChl) c antenna via smaller BChl a antennas to the reaction center. The effects of substituted 1,4-naphthoquinones on BChl c and BChl a fluorescence...

  6. Mimics of the self-assembling chlorosomal bacteriochlorophylls: regio- and stereoselective synthesis and stereoanalysis of acyl(1-hydroxyalkyl)porphyrins.

    Science.gov (United States)

    Balaban, Teodor Silviu; Bhise, Anil Dnyanoba; Bringmann, Gerhard; Bürck, Jochen; Chappaz-Gillot, Cyril; Eichhöfer, Andreas; Fenske, Dieter; Götz, Daniel C G; Knauer, Michael; Mizoguchi, Tadashi; Mössinger, Dennis; Rösner, Harald; Roussel, Christian; Schraut, Michaela; Tamiaki, Hitoshi; Vanthuyne, Nicolas

    2009-10-14

    Diacylation of copper 10,20-bis(3,5-di-tert-butylphenylporphyrin) using Friedel-Crafts conditions at short reaction times, high concentrations of catalyst, and 0-4 degrees C affords only the 3,17-diacyl-substituted porphyrins, out of the 12 possible regioisomers. At longer reaction times and higher temperatures, the 3,13-diacyl compounds are also formed, and the two isomers can be conveniently separated by normal chromatographic techniques. Monoreduction of these diketones affords in good yields the corresponding acyl(1-hydroxyalkyl)porphyrins, which after zinc metalation are mimics of the natural chlorosomal bacteriochlorophyll (BChl) d. Racemate resolution by HPLC on a variety of chiral columns was achieved and further optimized, thus permitting easy access to enantiopure porphyrins. Enantioselective reductions proved to be less effective in this respect, giving moderate yields and only 79% ee in the best case. The absolute configuration of the 3(1)-stereocenter was assigned by independent chemical and spectroscopic methods. Self-assembly of a variety of these zinc BChl d mimics proves that a collinear arrangement of the hydroxyalkyl substituent with the zinc atom and the carbonyl substituent is not a stringent requirement, since both the 3,13 and the 3,17 regioisomers self-assemble readily as the racemates. Interestingly, the separated enantiomers self-assemble less readily, as judged by absorption, fluorescence, and transmission electron microscopy studies. Circular dichroism spectra of the self-assemblies show intense Cotton effects, which are mirror-images for the two 3(1)-enantiomers, proving that the supramolecular chirality is dependent on the configuration at the 3(1)-stereocenter. Upon disruption of these self-assemblies with methanol, which competes with zinc ligation, only very weak monomeric Cotton effects are present. The favored heterochiral self-assembly process may also be encountered for the natural BChls. This touches upon the long

  7. Multireference excitation energies for bacteriochlorophylls A within light harvesting system 2

    DEFF Research Database (Denmark)

    Anda, Andre; Hansen, Thorsten; De Vico, Luca

    2016-01-01

    Light-harvesting system 2 (LH2) of purple bacteria is one of the most popular antenna complexes used to study Nature's way of collecting and channeling solar energy. The dynamics of the absorbed energy is probed by ultrafast spectroscopy. Simulation of these experiments relies on fitting a range...... bacteriochlorophylls in LH2. We find that the excitation energies vary among the bacteriochlorophyll monomers and that they are regulated by the curvature of the macrocycle ring and the dihedral angle of an acetyl moiety. Increasing the curvature lifts the ground state energy, which causes a red shift...... prove instrumental in exposing the underlying physics of photosynthetic light-harvesting....

  8. Design of a minimal polypeptide unit for bacteriochlorophyll binding and self-assembly based on photosynthetic bacterial light-harvesting proteins.

    Science.gov (United States)

    Noy, Dror; Dutton, P Leslie

    2006-02-21

    We introduce LH1beta24, a minimal 24 amino acid polypeptide that binds and assembles bacteriochlorophylls (BChls) in micelles of octyl beta-glucoside (OG) into complexes with spectral properties that resemble those of B820, a universal intermediate in the assembly of native purple bacterial light-harvesting complexes (LHs). LH1beta24 was designed by a survey of sequences and crystal structures of bacterial LH proteins from different organisms combined with currently available information from in vitro reconstitution studies and genetically modified LHs in vivo. We took as a template for the design sphbeta31, a truncated 31 amino acid analogue of the native beta-apoprotein from the core LH complex of Rhodobacter sphaeroides. This peptide self-assembles with BChls to form B820 and, upon cooling and lowering OG concentration, forms red-shifted B850 spectral species that are considered analogous to native LH complexes. We find that LH1beta24 self-assembles with BChl in OG to form homodimeric B820-type subunits comprising two LH1beta24 and two BChl molecules per subunit. We demonstrate, by modeling the structure using the highly homologous structure of LH2 from Rhodospirillum molischianum, that it has the minimal size for BChl binding. Additionally, we have compared the self-assembly of sphbeta31 and LH1beta24 with BChls and discovered that the association enthalpies and entropies of both species are similar to those measured for native LH1 from Rhodospirillum rubrum. However, sphbeta31 readily aggregates into intermediate higher oligomeric species and further to form B850 species; moreover, the assembly process of these oligomers is not reversible, and they are apparently large nonspecific BChl-peptide coaggregates rather than well-defined nativelike LH complexes. Similar aggregates were observed during LH1beta24 assembly, but these were formed less readily and required lower temperatures than sphbeta31. In view of these results, we reevaluate previous in vitro

  9. Probing the Role of the Eighth Bacteriochlorophyll in holo-FMO Complex by Simulated Two-Dimensional Electronic Spectroscopy

    CERN Document Server

    Yeh, Shu-Hao

    2014-01-01

    The Fenna-Matthews-Olson (FMO) protein-pigment complex acts as a molecular wire between the outer antenna system and the reaction center (RC); it is an important model system to study the excitonic energy transfer. Recent crystallographic studies report the existence of an additional (eighth) bacteriochlorophyll a (BChl a). To understand the functionality of this eighth BChl, we simulated the two-dimensional electronic spectra of both the 7-site (apo form) and the 8-site (holo form) variant of the FMO complex from green sulfur bacteria, Prosthecochloris aestuarii. By comparing the difference between the spectrum, it was found that the eighth BChl can affect two different excitonic energy transfer pathways, these being: (1) directly involve in the first pathway 6 $\\rightarrow$ 3 $\\rightarrow$ 1 of the apo form model by passing the excitonic energy to exciton 6; and (2) increase the excitonic wave function overlap between excitons 4 and 5 in the second pathway (7 $\\rightarrow$ 4,5 $\\rightarrow$ 2 $\\rightarrow$ ...

  10. Derivative Form of Off-axis Aberration Correction Surface and Its Application in Solar Energy Concentration

    Institute of Scientific and Technical Information of China (English)

    LI Li; CHEN Ying-Tian; HU Sen

    2009-01-01

    By using the derivative method, we obtained the same result with that of the previous work of Chen et al.in 2006.Different from the integral form, the derivative form of the surface expression published in this paper is derived from differential equation and based on the theory of non-imaging focusing heliostat proposed by Chen et al.in 2001.The comparison of the derivative form of fixed aberration correction surface has been made with that of integral form surface as well as that of spherical surface in concentrating the solar ray.

  11. Pressure-assisted forming of non-concentric tubular cross sections with solid medium

    DEFF Research Database (Denmark)

    Alves, Luis M.; Silva, Carlos M.A.; Nielsen, Chris V.;

    2016-01-01

    hydroforming) or elastomers (tube rubber forming) as pressuring medium, the subject matter of this article is centred in the utilization of low melting point, recyclable, metallic alloys as solid pressurizing medium. The aims and scope of the article are centred on the feasibility of forming straight carbon...... plastic deformation and prevent collapse can be successfully and effectively employed to fabricate non-concentric tubular cross sections for prototypes and small batches of lightweight components....

  12. Recent Progress in Chemical Modifications of Chlorophylls and Bacteriochlorophylls for the Applications in Photodynamic Therapy.

    Science.gov (United States)

    Staron, Jakub; Boron, Bożena; Karcz, Dariusz; Szczygieł, Małgorzata; Fiedor, Leszek

    2015-01-01

    Since photodynamic therapy emerged as a promising cancer treatment, the development of photosensitizers has gained great interest. In this context, the photosynthetic pigments, chlorophylls and bacteriochlorophylls, as excellent natural photosensitizers, attracted much attention. In effect, several (bacterio) chlorophyll-based phototherapeutic agents have been developed and (or are about to) enter the clinics. The aim of this review article is to give a survey of the advances in the synthetic chemistry of these pigments which have been made over the last decade, and which are pertinent to the application of their derivatives as photosensitizers for photodynamic therapy (PDT). The review focuses on the synthetic strategies undertaken to obtain novel derivatives of (bacterio)chlorophylls with both enhanced photosensitizing and tumorlocalizing properties, and also improved photo- and chemical stability. These include modifications of the C- 17-ester moiety, the isocyclic ring, the central binding pocket, and the derivatization of peripheral functionalities at the C-3 and C-7 positions with carbohydrate-, peptide-, and nanoparticle moieties or other residues. The effects of these modifications on essential features of the pigments are discussed, such as the efficiency of reactive oxygen species generation, photostability, phototoxicity and interactions with living organisms. The review is divided into several sections. In the first part, the principles of PDT and photosensitizer action are briefly described. Then the relevant photophysical features of (bacterio)chlorophylls and earlier approaches to their modification are summarized. Next, a more detailed overview of the progress in synthetic methods is given, followed by a discussion of the effects of these modifications on the photophysics of the pigments and on their biological activity. PMID:26282940

  13. Molecular genetic and molecular evolutionary studies on the bacteriochlorophyll synthesis genes of Rhodobacter capsulatus

    Energy Technology Data Exchange (ETDEWEB)

    Burke-Agueero, D.H.

    1992-08-01

    Rhodobacter capsulatus, purple bacterium capable of either aerobic or photosynthetic growth, has proven to be very useful in genetic studies of photosynthesis. Forty-four genes clustered together within a 46 kilobase region are required to establish photosynthetic ability in R. capsulatus. Approximately twenty of these genes are involved in bacteriochlorophyll synthesis of which eight bch'' genes are the subject of this thesis. Six of these genes were found to code for the two ring reductases. The first converts protochlorophyllide (PChlide) into a chlorin, the immediate precursor to chlorophyll a, and then into a bacteriochlorin. Each reductase is shown to be made up of three subunits. PChlide reductase is coded by the genes bchN, bchB, and bchL. Proteins with amino acid sequences markedly similar to those of bchN and bchL have been shown in other organisms to be required for chlorophyll synthesis; hence, their designation as chlN and chlB. A third chloroplast-encoded gene of heretofore unknown function shares amino acid identities with bchB and is probably the third subunit of the plant PChlide reductase. The bchA locus, which encodes the chlorin reductase, is found to be made up of three separate, translationally coupled genes, referred to as bchX, bchY, and bchZ. Amino acid similarities between bchX, bchL, and the nitrogenase reductase protein nifH suggest that all three classes of proteins share certain three-dimensional structural features, including elements that are central to the enzymatic mechanism of nifH. PChlide reductase and chlorin reductase are clearly derived from a common ancestor. Several lines of analysis suggests the ancestor of both enzyme systems reduced PChlide twice to produce bacteriochlorophyll supporting the concept bacteriochlorophyll as the ancestral reaction center pigment.

  14. Molecular genetic and molecular evolutionary studies on the bacteriochlorophyll synthesis genes of Rhodobacter capsulatus

    Energy Technology Data Exchange (ETDEWEB)

    Burke-Agueero, D.H.

    1992-08-01

    Rhodobacter capsulatus, purple bacterium capable of either aerobic or photosynthetic growth, has proven to be very useful in genetic studies of photosynthesis. Forty-four genes clustered together within a 46 kilobase region are required to establish photosynthetic ability in R. capsulatus. Approximately twenty of these genes are involved in bacteriochlorophyll synthesis of which eight ``bch`` genes are the subject of this thesis. Six of these genes were found to code for the two ring reductases. The first converts protochlorophyllide (PChlide) into a chlorin, the immediate precursor to chlorophyll a, and then into a bacteriochlorin. Each reductase is shown to be made up of three subunits. PChlide reductase is coded by the genes bchN, bchB, and bchL. Proteins with amino acid sequences markedly similar to those of bchN and bchL have been shown in other organisms to be required for chlorophyll synthesis; hence, their designation as chlN and chlB. A third chloroplast-encoded gene of heretofore unknown function shares amino acid identities with bchB and is probably the third subunit of the plant PChlide reductase. The bchA locus, which encodes the chlorin reductase, is found to be made up of three separate, translationally coupled genes, referred to as bchX, bchY, and bchZ. Amino acid similarities between bchX, bchL, and the nitrogenase reductase protein nifH suggest that all three classes of proteins share certain three-dimensional structural features, including elements that are central to the enzymatic mechanism of nifH. PChlide reductase and chlorin reductase are clearly derived from a common ancestor. Several lines of analysis suggests the ancestor of both enzyme systems reduced PChlide twice to produce bacteriochlorophyll supporting the concept bacteriochlorophyll as the ancestral reaction center pigment.

  15. Self-assembly of natural light-harvesting bacteriochlorophylls of green sulfur photosynthetic bacteria in silicate capsules as stable models of chlorosomes.

    Science.gov (United States)

    Saga, Yoshitaka; Akai, Sho; Miyatake, Tomohiro; Tamiaki, Hitoshi

    2006-01-01

    Naturally occurring bacteriochlorophyll(BChl)s-c, -d, and -e from green sulfur photosynthetic bacteria were self-assembled in an aqueous solution in the presence of octadecyltriethoxysilane and tetraethoxysilane, followed by polycondensation of the alkoxysilanes by incubation for 50 h at 25 degrees C. The resulting BChl self-assemblies in silicate capsules exhibited visible absorption and circular dichroism spectra similar to the corresponding natural light-harvesting systems (chlorosomes) of green sulfur bacteria. Dynamic light scattering measurements indicated that the silicate capsules had an average hydrodynamic diameter of several hundred nanometers. BChl self-aggregates in silicate capsules were significantly stable to a nonionic surfactant Triton X-100, which was apt to decompose the BChl aggregates to their monomeric form, compared with conventional micelle systems. BChls in silicate capsules were more tolerant to demetalation of the central magnesium under acidic conditions than the natural systems. PMID:16848406

  16. Absence of the cbb3 Terminal Oxidase Reveals an Active Oxygen-Dependent Cyclase Involved in Bacteriochlorophyll Biosynthesis in Rhodobacter sphaeroides

    Science.gov (United States)

    Chen, Guangyu E.; Martin, Elizabeth C.; Hunter, C. Neil

    2016-01-01

    ABSTRACT The characteristic green color associated with chlorophyll pigments results from the formation of an isocyclic fifth ring on the tetrapyrrole macrocycle during the biosynthesis of these important molecules. This reaction is catalyzed by two unrelated cyclase enzymes employing different chemistries. Oxygenic phototrophs such as plants and cyanobacteria utilize an oxygen-dependent enzyme, the major component of which is a diiron protein named AcsF, while BchE, an oxygen-sensitive [4Fe-4S] cluster protein, dominates in phototrophs inhabiting anoxic environments, such as the purple phototrophic bacterium Rhodobacter sphaeroides. We identify a potential acsF in this organism and assay for activity of the encoded protein in a strain lacking bchE under various aeration regimes. Initially, cells lacking bchE did not demonstrate AcsF activity under any condition tested. However, on removal of a gene encoding a subunit of the cbb3-type respiratory terminal oxidase, cells cultured under regimes ranging from oxic to micro-oxic exhibited cyclase activity, confirming the activity of the oxygen-dependent enzyme in this model organism. Potential reasons for the utilization of an oxygen-dependent enzyme in anoxygenic phototrophs are discussed. IMPORTANCE The formation of the E ring of bacteriochlorophyll pigments is the least well characterized step in their biosynthesis, remaining enigmatic for over 60 years. Two unrelated enzymes catalyze this cyclization step; O2-dependent and O2-independent forms dominate in oxygenic and anoxygenic phototrophs, respectively. We uncover the activity of an O2-dependent enzyme in the anoxygenic purple phototrophic bacterium Rhodobacter sphaeroides, initially by inactivation of the high-affinity terminal respiratory oxidase, cytochrome cbb3. We propose that the O2-dependent form allows for the biosynthesis of a low level of bacteriochlorophyll under oxic conditions, so that a rapid initiation of photosynthetic processes is possible for

  17. Third order nonlinear optical properties of stacked bacteriochlorophylls in bacterial photosynthetic light-harvesting proteins

    Energy Technology Data Exchange (ETDEWEB)

    Chen, L.X.; Laible, P.D. [Argonne National Lab., IL (United States). Chemistry Div.; Spano, F.C.; Manas, E.S. [Temple Univ., Philadelphia, PA (United States). Dept. of Chemistry

    1997-09-01

    Enhancement of the nonresonant second order molecular hyperpolarizabilities {gamma} were observed in stacked macrocyclic molecular systems, previously in a {micro}-oxo silicon phthalocyanine (SiPcO) monomer, dimer and trimer series, and now in bacteriochlorophyll a (BChla) arrays of light harvesting (LH) proteins. Compared to monomeric BChla in a tetrahydrofuran (THF) solution, the <{gamma}> for each macrocycle was enhanced in naturally occurring stacked macrocyclic molecular systems in the bacterial photosynthetic LH proteins where BChla`s are arranged in tilted face-to-face arrays. In addition, the {gamma} enhancement is more significant in B875 of LH1 than in B850 in LH2. Theoretical modeling of the nonresonant {gamma} enhancement using simplified molecular orbitals for model SiPcO indicated that the energy level of the two photon state is crucial to the {gamma} enhancement when a two photon process is involved, whereas the charge transfer between the monomers is largely responsible when one photon near resonant process is involved. The calculated results can be extended to {gamma} enhancement in B875 and B850 arrays, suggesting that BChla in B875 are more strongly coupled than in B850. In addition, a 50--160 fold increase in <{gamma}> for the S{sub 1} excited state of relative to S{sub 0} of bacteriochlorophyll in vivo was observed which provides an alternative method for probing excited state dynamics and a potential application for molecular switching.

  18. Carotenoid-bacteriochlorophyll energy transfer in LH2 complexes studied with 10-fs time resolution.

    Science.gov (United States)

    Polli, Dario; Cerullo, Giulio; Lanzani, Guglielmo; De Silvestri, Sandro; Hashimoto, Hideki; Cogdell, Richard J

    2006-04-01

    In this report, we present a study of carotenoid-bacteriochlorophyll energy transfer processes in two peripheral light-harvesting complexes (known as LH2) from purple bacteria. We use transient absorption spectroscopy with approximately 10 fs temporal resolution, which is necessary to observe the very fast energy relaxation processes. By comparing excited-state dynamics of the carotenoids in organic solvents and inside the LH2 complexes, it has been possible to directly evaluate their energy transfer efficiency to the bacteriochlorophylls. In the case of okenone in the LH2 complex from Chromatium purpuratum, we obtained an energy transfer efficiency of etaET2=63+/-2.5% from the optically active excited state (S2) and etaET1=61+/-2% from the optically dark state (S1); for rhodopin glucoside contained in the LH2 complex from Rhodopseudomonas acidophila these values become etaET2=49.5+/-3.5% and etaET1=5.1+/-1%. The measurements also enabled us to observe vibrational energy relaxation in the carotenoids' S1 state and real-time collective vibrational coherence initiated by the ultrashort pump pulses. Our results are important for understanding the dynamics of early events of photosynthesis and relating it to the structural arrangement of the chromophores.

  19. Closed-form solution for a cantilevered sectorial plate subjected to a tip concentrated force.

    Science.gov (United States)

    Christy, Carl W; Weggel, David C; Smelser, R E

    2016-01-01

    A closed-form solution is presented for a cantilevered sectorial plate subjected to a tip concentrated force. Since the particular solution for this problem was not found in the literature, it is derived here. Deflections from the total solution (particular plus homogeneous solutions) are compared to those from a finite element analysis and are found to be in excellent agreement, producing an error within approximately 0.08 %. Normalized closed-form deflections and slopes at the fixed support, resulting from an approximate enforcement of the boundary conditions there, deviate from zero by cantilevered sectorial plate subjected to independent applications of a tip concentrated force, a tip bending moment, and a tip twisting moment, are compiled. PMID:27390653

  20. Chlorobium tepidum mutant lacking bacteriochlorophyll c made by inactivation of the bchK gene, encoding bacteriochlorophyll c synthase

    DEFF Research Database (Denmark)

    Frigaard, Niels-Ulrik; Voigt, Ginny D; Bryant, Donald A

    2002-01-01

    The gene encoding bacteriochlorophyll (BChl) c synthase was identified by insertional inactivation in the photosynthetic green sulfur bacterium Chlorobium tepidum and was named bchK. The bchK mutant of C. tepidum was rusty-orange in color and completely lacked BChl c. Because of the absence...

  1. Broadband 2D Electronic Spectroscopy Reveals Coupling Between Dark 1Bu- State of Carotenoid and Qx State of Bacteriochlorophyll

    Directory of Open Access Journals (Sweden)

    Scholes Gregory D.

    2013-03-01

    Full Text Available The study of LH2 protein of purple bacteria by broadband 2D electronic spectroscopy is presented. The dark 1Bu- carotenoid state is directly observed in 2D spectra and its role in carotenoid-bacteriochlorophyll interaction is discussed.

  2. Waste Form and Indrift Colloids-Associated Radionuclide Concentrations: Abstraction and Summary

    Energy Technology Data Exchange (ETDEWEB)

    R. Aguilar

    2003-06-24

    This Model Report describes the analysis and abstractions of the colloids process model for the waste form and engineered barrier system components of the total system performance assessment calculations to be performed with the Total System Performance Assessment-License Application model. Included in this report is a description of (1) the types and concentrations of colloids that could be generated in the waste package from degradation of waste forms and the corrosion of the waste package materials, (2) types and concentrations of colloids produced from the steel components of the repository and their potential role in radionuclide transport, and (3) types and concentrations of colloids present in natural waters in the vicinity of Yucca Mountain. Additionally, attachment/detachment characteristics and mechanisms of colloids anticipated in the repository are addressed and discussed. The abstraction of the process model is intended to capture the most important characteristics of radionuclide-colloid behavior for use in predicting the potential impact of colloid-facilitated radionuclide transport on repository performance.

  3. Waste Form and Indrift Colloids-Associated Radionuclide Concentrations: Abstraction and Summary

    International Nuclear Information System (INIS)

    This Model Report describes the analysis and abstractions of the colloids process model for the waste form and engineered barrier system components of the total system performance assessment calculations to be performed with the Total System Performance Assessment-License Application model. Included in this report is a description of (1) the types and concentrations of colloids that could be generated in the waste package from degradation of waste forms and the corrosion of the waste package materials, (2) types and concentrations of colloids produced from the steel components of the repository and their potential role in radionuclide transport, and (3) types and concentrations of colloids present in natural waters in the vicinity of Yucca Mountain. Additionally, attachment/detachment characteristics and mechanisms of colloids anticipated in the repository are addressed and discussed. The abstraction of the process model is intended to capture the most important characteristics of radionuclide-colloid behavior for use in predicting the potential impact of colloid-facilitated radionuclide transport on repository performance

  4. Hexanol-induced order-disorder transitions in lamellar self-assembling aggregates of bacteriochlorophyll c in Chlorobium tepidum chlorosomes.

    Science.gov (United States)

    Arellano, Juan B; Torkkeli, Mika; Tuma, Roman; Laurinmäki, Pasi; Melø, Thor B; Ikonen, Teemu P; Butcher, Sarah J; Serimaa, Ritva E; Psencík, Jakub

    2008-03-01

    Chlorosomes are light-harvesting complexes of green photosynthetic bacteria. Chlorosomes contain bacteriochlorophyll (BChl) c, d, or e aggregates that exhibit strong excitonic coupling. The short-range order, which is responsible for the coupling, has been proposed to be augmented by pigment arrangement into undulated lamellar structures with spacing between 2 and 3 nm. Treatment of chlorosomes with hexanol reversibly converts the aggregated chlorosome chlorophylls into a form with spectral properties very similar to that of the monomer. Although this transition has been extensively studied, the structural basis remains unclear due to variability in the obtained morphologies. Here we investigated hexanol-induced structural changes in the lamellar organization of BChl c in chlorosomes from Chlorobium tepidum by a combination of X-ray scattering, electron cryomicroscopy, and optical spectroscopy. At a low hexanol/pigment ratio, the lamellae persisted in the presence of hexanol while the short-range order and exciton interactions between chlorin rings were effectively eliminated, producing a monomer-like absorption. The result suggested that hexanol hydroxyls solvated the chlorin rings while the aliphatic tail partitioned into the hydrophobic part of the lamellar structure. This partitioning extended the chlorosome along its long axis. Further increase of the hexanol/pigment ratio produced round pigment-hexanol droplets, which lost all lamellar order. After hexanol removal the spectral properties were restored. In the samples treated under the high hexanol/pigment ratio, lamellae reassembled in small domains after hexanol removal while the shape and long-range order were irreversibly lost. Thus, all the interactions required for establishing the short-range order by self-assembly are provided by BChl c molecules alone. However, the long-range order and overall shape are imposed by an external structure, e.g., the proteinaceous chlorosome baseplate. PMID:18197717

  5. Identification of novel fluorinated surfactants in aqueous film forming foams and commercial surfactant concentrates.

    Science.gov (United States)

    D'Agostino, Lisa A; Mabury, Scott A

    2014-01-01

    Recent studies comparing the results of total organofluorine-combustion ion chromatography (TOF-CIC) to targeted analysis of perfluoroalkyl and polyfluoroalkyl substances (PFASs) by liquid chromatography tandem mass spectrometry (LC-MS/MS) have shown that a significant yet variable portion of the total organofluorine in environmental and biological samples is in the form of unknown PFASs. A portion of this unknown organofluorine likely originates in proprietary fluorinated surfactants not included in LC-MS/MS analyses and not fully characterized by the environmental science community, which may enter the environment through use in aqueous film forming foams (AFFFs) for firefighting. Contamination of water, biota, and soils with various PFASs due to AFFF deployment has been documented. Ten fluorinated AFFF concentrates, 9 of which were obtained from fire sites in Ontario, Canada, and two commercial fluorinated surfactant concentrates were characterized in order to identify novel fluorinated surfactants. Mixed-mode ion exchange solid phase extraction (SPE) fractionated fluorinated surfactants based on ionic character. High resolution mass spectrometry assigned molecular formulas to fluorinated surfactant ions, while collision induced dissociation (CID) spectra assisted structural elucidation. LC-MS/MS detected isomers and low abundance fluorinated chain lengths. In total, 12 novel and 10 infrequently reported PFAS classes were identified in fluorinated chain lengths from C3 to C15 for a total of 103 compounds. Further research should examine the environmental fate and toxicology of these PFASs, especially their potential as perfluoroalkyl acid (PFAA) precursors. PMID:24256061

  6. A repeat protein links Rubisco to form the eukaryotic carbon-concentrating organelle.

    Science.gov (United States)

    Mackinder, Luke C M; Meyer, Moritz T; Mettler-Altmann, Tabea; Chen, Vivian K; Mitchell, Madeline C; Caspari, Oliver; Freeman Rosenzweig, Elizabeth S; Pallesen, Leif; Reeves, Gregory; Itakura, Alan; Roth, Robyn; Sommer, Frederik; Geimer, Stefan; Mühlhaus, Timo; Schroda, Michael; Goodenough, Ursula; Stitt, Mark; Griffiths, Howard; Jonikas, Martin C

    2016-05-24

    Biological carbon fixation is a key step in the global carbon cycle that regulates the atmosphere's composition while producing the food we eat and the fuels we burn. Approximately one-third of global carbon fixation occurs in an overlooked algal organelle called the pyrenoid. The pyrenoid contains the CO2-fixing enzyme Rubisco and enhances carbon fixation by supplying Rubisco with a high concentration of CO2 Since the discovery of the pyrenoid more that 130 y ago, the molecular structure and biogenesis of this ecologically fundamental organelle have remained enigmatic. Here we use the model green alga Chlamydomonas reinhardtii to discover that a low-complexity repeat protein, Essential Pyrenoid Component 1 (EPYC1), links Rubisco to form the pyrenoid. We find that EPYC1 is of comparable abundance to Rubisco and colocalizes with Rubisco throughout the pyrenoid. We show that EPYC1 is essential for normal pyrenoid size, number, morphology, Rubisco content, and efficient carbon fixation at low CO2 We explain the central role of EPYC1 in pyrenoid biogenesis by the finding that EPYC1 binds Rubisco to form the pyrenoid matrix. We propose two models in which EPYC1's four repeats could produce the observed lattice arrangement of Rubisco in the Chlamydomonas pyrenoid. Our results suggest a surprisingly simple molecular mechanism for how Rubisco can be packaged to form the pyrenoid matrix, potentially explaining how Rubisco packaging into a pyrenoid could have evolved across a broad range of photosynthetic eukaryotes through convergent evolution. In addition, our findings represent a key step toward engineering a pyrenoid into crops to enhance their carbon fixation efficiency. PMID:27166422

  7. Biosynthesis of unnatural bacteriochlorophyll c derivatives esterified with α,ω-diols in the green sulfur photosynthetic bacterium Chlorobaculum tepidum.

    Science.gov (United States)

    Nishimori, Risato; Mizoguchi, Tadashi; Tamiaki, Hitoshi; Kashimura, Shigenori; Saga, Yoshitaka

    2011-09-13

    Unnatural bacteriochlorophyll (BChl) c derivatives possessing a hydroxy group at the terminus of a hydrocarbon chain at the 17-propionate were biosynthesized in the green sulfur photosynthetic bacterium Chlorobaculum tepidum. Addition of exogenous 1,8-octanediol, 1,12-dodecanediol, and 1,16-hexadecanediol in acetone to liquid cultures resulted in accumulation of BChl c monoesterified with the corresponding diols. The relative ratios of the novel BChl c derivatives esterified with 1,8-, 1,12-, and 1,16-diols to totally producing BChl c were 8.2, 50.2, and 57.6% in the cells grown with additive α,ω-diols at concentrations of 1.5, 0.06, and 0.06 mM, respectively, at the final concentration. The homologue composition of BChl c derivatives esterified with these α,ω-diols was similar to that of original, coexisting BChl c esterified with farnesol (BChl c(F)), suggesting that esterification of α,ω-diols occurred at the last step of the BChl c biosynthetic pathway by BChl c synthase, BchK, in the same manner as in BChl c(F). Chlorosomes, which were isolated from cells grown in the presence of exogenous α,ω-diols, contained a ratio and a composition of BChl c derivatives esterified with the diols similar to those in the whole cells, indicating that these BChl c derivatives were actually present in chlorosomes. Q(y) absorption bands of C. tepidum cells containing the novel BChl c derivatives were shifted to a shorter wavelength, although their bandwidths were analogous to those of cells obtained by normal cultivation. Circular dichroism spectra of cells that had BChl c derivatives esterified with α,ω-diols exhibited S-shaped signals in the Q(y) region, whose polarities were the reverse of those of cells grown in the normal medium and by supplementation with neat acetone as a control experiment. These spectral features of C. tepidum possessing BChl c derivatives esterified with α,ω-diols imply that the novel BChl c derivatives possessing a hydroxy group at the

  8. Vibronic coupling explains the ultrafast carotenoid-to-bacteriochlorophyll energy transfer in natural and artificial light harvesters

    OpenAIRE

    Perlík, Václav; Seibt, Joachim; Cranston, Laura J.; Cogdell, Richard J.; Lincoln, Craig N.; Savolainen, Janne; Šanda, František; Mančal, Tomáš; Hauer, Jürgen

    2015-01-01

    The initial energy transfer in photosynthesis occurs between the light-harvesting pigments and on ultrafast timescales. We analyze the carotenoid to bacteriochlorophyll energy transfer in LH2 Marichromatium purpuratum as well as in an artificial light-harvesting dyad system by using transient grating and two-dimensional electronic spectroscopy with 10 fs time resolution. We find that F\\"orster-type models reproduce the experimentally observed 60 fs transfer times, but overestimate coupling co...

  9. Competition of bloom-forming marine phytoplankton at low nutrient concentrations

    Institute of Scientific and Technical Information of China (English)

    Hanhua Hu; Jun Zhang; Weidong Chen

    2011-01-01

    Competition of three bloom-forming marine phytoplankton (diatom Skeletonema costatum, and dinoflagellates Prorocentrum minimum and Alexandrium tamarense) was studied through a series of multispecies cultures with different nitrate (NaNO3) and phosphate (NaH2PO4) levels and excess silicate to interpret red tide algae succession. S. costatum outgrew the other two dinoflagellates in nitrate and phosphate replete cultures with 10 μmol/L Na2SiO3. Under nitrate limited (8.82 μ mol/L NaNO3) conditions, the growth of S. costatum was also dominant when phosphate concentrations were from 3.6 to 108 μmol/L. Cell density of the two dinoflagellates only increased slighfly, to less than 400 and 600 cells/mL, respectively. Cell density of S. costatum decreased with time before day 12, and then increased to 4000 cells/mL (1.5 mg/L dry biomass) at NaNO3 concentrations between 88.2 and 882 μmol/L with limited phosphate (0.36 μmol/L NaH2PO4) levels. In addition, P. minimum grew well with a maximal cell density of 1690-2100 cells/mL (0.5-0.6 mg/L dry biomass). Although S. costatum initially grew fast, its cell density decreased quickly with time later in the growth phase and the two dinoflagellates were dominant under the nitrate-limited and high nitrate conditions with limited phosphate. These results indicated that the diatom was a poor competitor compared to the two dinoflagellates under limited phosphate; however, it grew well under limited nitrate when growth of the dinoflagellates was near detection limits.

  10. Competition of bloom-forming marine phytoplankton at low nutrient concentrations.

    Science.gov (United States)

    Hu, Hanhua; Zhang, Jun; Chen, Weidong

    2011-01-01

    Competition of three bloom-forming marine phytoplankton (diatom Skeletonema costatum, and dinoflagellates Prorocentrum minimum and Alexandrium tamarense) was studied through a series of multispecies cultures with different nitrate (NaNO3) and phosphate (NaH2PO4) levels and excess silicate to interpret red tide algae succession. S. costatum outgrew the other two dinoflagellates in nitrate and phosphate replete cultures with 10 micromol/L Na2SiO3. Under nitrate limited (8.82 micromol/L NaNO3) conditions, the growth of S. costatum was also dominant when phosphate concentrations were from 3.6 to 108 micromol/L. Cell density of the two dinoflagellates only increased slightly, to less than 400 and 600 cells/mL, respectively. Cell density of S. costatum decreased with time before day 12, and then increased to 4000 cells/mL (1.5 mg/L dry biomass) at NaNO3 concentrations between 88.2 and 882 micromol/L with limited phosphate (0.36 micromol/L NaH2PO4) levels. In addition, P. minimum grew well with a maximal cell density of 1690-2100 cells/mL (0.5-0.6 mg/L dry biomass). Although S. costatum initially grew fast, its cell density decreased quickly with time later in the growth phase and the two dinoflagellates were dominant under the nitrate-limited and high nitrate conditions with limited phosphate. These results indicated that the diatom was a poor competitor compared to the two dinoflagellates under limited phosphate; however, it grew well under limited nitrate when growth of the dinoflagellates was near detection limits. PMID:21793409

  11. Self-assembly of [Et,Et]-bacteriochlorophyll cF on highly oriented pyrolytic graphite revealed by scanning tunneling microscopy.

    Science.gov (United States)

    Möltgen, H; Kleinermanns, K; Jesorka, A; Schaffner, K; Holzwarth, A R

    2002-06-01

    The chlorosomal light-harvesting antennae of green phototrophic bacteria consist of large supramolecular aggregates of bacteriochlorophyll c (BChl c). The supramolecular structure of (3(1)-R/S)-BChl c on highly oriented pyrolytic graphite (HOPG) and molybdenum disulfide (MoS2) has been investigated by scanning tunneling microscopy (STM). On MoS2, we observed single BChl c molecules, dimers or tetramers, depending on the polarity of the solvent. On HOPG, we observed extensive self-assembly of the dimers and tetramers. We propose C=O...H-O...Mg bonding networks for the observed dimer chains, in agreement with former ultraviolet-visible and infrared spectroscopic work. The BChl c moieties in the tetramers are probably linked by four C=O...H-O hydrogen bonds to form a circle and further stabilized by Mg...O-H bondings to underlying BChl c layers. The tetramers form highly ordered, distinct chains and extended two-dimensional networks. We investigated semisynthetic chlorins for comparison by STM but observed that only BChl c self-assembles to well-structured large aggregates on HOPG. The results on the synthetic chlorins support our structure proposition. PMID:12081324

  12. Mutational analysis of three bchH paralogs in (bacterio-)chlorophyll biosynthesis in Chlorobaculum tepidum

    DEFF Research Database (Denmark)

    Gomez Maqueo Chew, Aline; Frigaard, Niels-Ulrik; Bryant, Donald A

    2009-01-01

    The first committed step in the biosynthesis of (bacterio-)chlorophyll is the insertion of Mg2+ into protoporphyrin IX by Mg-chelatase. In all known (B)Chl-synthesizing organisms, Mg-chelatase is encoded by three genes that are homologous to bchH, bchD, and bchI of Rhodobacter spp. The genomes...... of all sequenced strains of green sulfur bacteria (Chlorobi) encode multiple bchH paralogs, and in the genome of Chlorobaculum tepidum, there are three bchH paralogs, denoted CT1295 (bchT), CT1955 (bchS), and CT1957 (bchH). Cba. tepidum mutants lacking one or two of these paralogs were constructed...... and characterized. All of the mutants lacking only one of these BchH homologs, as well as bchS bchT and bchH bchT double mutants, which can only produce BchH or BchS, respectively, were viable. However, attempts to construct a bchH bchS double mutant, in which only BchT was functional, were consistently...

  13. Scrambled self-assembly of bacteriochlorophylls c and e in aqueous Triton X-100 micelles.

    Science.gov (United States)

    Saga, Yoshitaka; Saiki, Tatsuya; Takahashi, Naoya; Shibata, Yutaka; Tamiaki, Hitoshi

    2014-01-01

    Bacteriochlorophyll (BChl) e was coassembled with BChl c in Triton X-100 micelles in aqueous solutions. The Qy absorption bands of the coaggregates were positioned between those of aggregates consisting solely of BChl c or e. The electronic absorption spectra of the coaggregates could not be reproduced by linear combinations of the spectra of the aggregates consisting solely of each pigment, but they were in line with the simulated spectra for the self-aggregates in which both BChls were randomly distributed. These suggest that BChls c and e are not spatially separated; they are homogenously distributed over the self-aggregates to give electronic spectra that are different from those of the aggregate consisting solely of each pigment. Deaggregation of the scrambled self-aggregates by excess Triton X-100 did not produce any spectral components assigned to an aggregate consisting solely of either BChl c or e. Acid-induced decomposition of the scrambled aggregates showed different kinetics from those of the aggregates consisting solely of each pigment. These also support the homogeneous distribution of BChls c and e in the scrambled self-aggregates. These results will be useful to investigate the major light-harvesting antenna systems of green photosynthetic bacteria that contain two kinds of chlorosomal BChls. PMID:24308290

  14. Enzyme-catalyzed organic syntheses: transesterification reactions of chlorophyl a, bacteriochlorophyll a, and derivatives with chlorophyllase

    Energy Technology Data Exchange (ETDEWEB)

    Michalski, T.J.; Hunt, J.E.; Bradshaw, C.; Wagner, A.M.; Norris, J.R.; Katz, J.J.

    1988-08-17

    The green plant enzyme chlorophyllase (EC 3.1.1.14, chlorophyll chlorophyllido-hydroase) has been used for the synthesis of a variety of primary alcohol and diol esters of chlorophyll a, bacteriochlorophyll a, and pyrobacteriochlorophyll a. Green plant chlorophyllase accepts a much larger range of alcohol and chlorophyll substrates than had previously been realized. Thus, chlorophyllide and bacteriochlorophyllide esters of primary alcohols such as retinol and the detergent Triton X-100 and of dihydric alcohols such as ethylene glycol, butanediol, or 2-hydroxyethyl disulfide can readily be obtained by enzyme-assisted transesterification. The diol chlorophyllide esters are valuable intermediates for the synthesis of reaction center special pair models. Chlorophyllase-assisted reactions can be carried out in media containing up to 95% of organic solvents without the concomitant side reactions that important chlorophyll functional groups readily undergo even under mild conditions in conventional chemical synthetic procedures. In competitive chlorophyllase-catalyzed transesterification reactions, long-chain alcohols such as farnesol and retinol vs simple aliphatic alcohols and diols, the enzyme shows a definite preference for the long-chain alcohol. 37 references, 1 figure, 2 tables.

  15. What determines the calcium concentration of speleothem-forming drip waters?

    Science.gov (United States)

    Baker, Andy; Flemons, Ingrid; Andersen, Martin S.; Coleborn, Katie; Treble, Pauline C.

    2016-08-01

    Cave drip water calcium ion concentration is a primary determinant of speleothem deposition and growth rate. The factors that determine drip water calcium ion concentrations are the soil and vadose zone CO2 concentrations, and the hydrogeochemical evolution of the water from soil to cave. Here, we use a systematic literature review of cave drip water calcium concentrations, combined with PHREEQC equilibrium modelling, to investigate the global relationship between calcium concentration and surface climate. Our results are discussed in the context of understanding the climatic and environmental controls on drip water calcium concentration, speleothem growth rates and proxies of past climate and environmental change. We use an empirical, global soil CO2 concentration-temperature relationship to derive PHREEQC modelled cave drip water calcium concentrations. The global mean modelled drip water calcium concentration is close to that observed, but it over-predicts at high and low temperatures, and significantly under-predicts at temperate conditions. We hypothesise that closed system hydrochemical evolution due to water saturation is an important control on carbonate dissolution at colder temperatures. Under warmer conditions, for example temperate climates with a dry and hot or warm summer, seasonally-limited water availability can lead to: climates with no dry season, higher CO2 concentrations than modelled from soil values are necessary to explain the observed drip water calcium values, which we propose is from an additional source of CO2 from microbial activity and root respiration in the vadose zone during open system hydrochemical evolution.

  16. Analytic free-form lens design for tracking integration in concentrating photovoltaics

    OpenAIRE

    Duerr, Fabian; Benitez Gimenez, Pablo; Miñano Dominguez, Juan Carlos; Meuret, Youri; Thienpont, Hugo

    2012-01-01

    In this work the concept of tracking integration in concentrating photovoltaics (CPV) is revisited and developed further. With respect to conventional CPV, tracking integration eliminates the clear separation between stationary units of optics and solar cells, and external solar trackers. This approach is capable of further increasing the concentration ratio and makes high concentrating photovoltaics (> 500x) available for single-axis tracker installations. The reduced external solar tracking...

  17. Characterization of an FMO Variant of Chlorobaculum tepidum Carrying Bacteriochlorophyll a Esterified by Geranylgeraniol

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Jianzhong [Washington Univ., St. Louis, MO (United States); Harada, Jiro [Ritsumeikan Univ., Shiga (Japan); Buyle, Kenny [Washington Univ., St. Louis, MO (United States); Yuan, Kevin [Washington Univ., St. Louis, MO (United States); Tamiaki, Hitoshi [Ritsumeikan Univ., Shiga (Japan); Oh-oka, Hirozo [Osaka Univ., Suita (Japan); Loomis, Richard A [Washington Univ., St. Louis, MO (United States); Blankenship, R. E. [Washington Univ., St. Louis, MO (United States)

    2010-06-15

    The Fenna-Matthews-Olson light-harvesting antenna (FMO) protein has been a model system for understanding pigment-protein interactions in the energy transfer process in photosynthesis. All previous studies have utilized wild-type FMO proteins from several species. Here we report the purification and characterization of the first FMO protein variant generated via replacement of the esterifying alcohol at the C-17 propionate residue of bacteriochlorophyll (BChl) a, phytol, with geranylgeraniol, which possesses three more double bonds. The FMO protein still assembles with the modified pigment, but both the whole cell absorption and the biochemical purification indicate that the mutant cells contain a much less mature FMO protein. The gene expression was checked using qRT-PCR, and none of the genes encoding BChl a-binding proteins are strongly regulated at the transcriptional level. The smaller amount of the FMO protein in the mutant cell is probably due to the degradation of the apo-FMO protein at different stages after it does not bind the normal pigment. The absorption, fluorescence, and CD spectra of the purified FMO variant protein are similar to those of the wild-type FMO protein except the conformations of most pigments are more heterogeneous, which broadens the spectral bands. Interestingly, the lowest-energy pigment binding site seems to be unchanged and is the only peak that can be well resolved in 77 K absorption spectra. The excited-state lifetime of the variant FMO protein is unchanged from that of the wild type and shows a temperature-dependent modulation similar to that of the wild type. The variant FMO protein is less thermally stable than the wild type. The assembly of the FMO protein and also the implications of the decreased FMO/chlorosome stoichiometry are discussed in terms of the topology of these two antennas on the cytoplasmic membrane.

  18. The effects of inorganic nitrogen form and CO2 concentration on wheat yield and nutrient accumulation and distribution

    Directory of Open Access Journals (Sweden)

    Eli eCarlisle

    2012-09-01

    Full Text Available Nitrogen (N is the most limiting nutrient for plant growth and primary productivity. Inorganic N is available to plants from the soil as ammonium (NH4+ and nitrate (NO3–. We studied how wheat grown hydroponically to senescence in controlled environmental chambers is affected by N form (NH4+ vs. NO3– and CO2 concentration (‘subambient’, ‘ambient’, and ‘elevated’ in terms of biomass, yield, and nutrient accumulation and partitioning. NH4+-grown wheat had the strongest response to CO2 concentration. Plants exposed to subambient and ambient CO2 concentrations typically had the greatest biomass and nutrient accumulation under both N forms. In general NH4+ plants had higher concentrations of total N, P, K, S, Ca, Zn, Fe, and Cu, while NO3– plants had higher concentrations of Mg, B, Mn, and NO3–-N. NH4+ plants contained amounts of phytate similar to NO3– plants but had higher bioavailable Zn, which could have ramifications for human health. NH4+ plants allocated more nutrients and biomass to aboveground tissues whereas NO3– plants allocated more nutrients to the roots. The two inorganic nitrogen forms influenced plant growth and nutrient status so distinctly that they should be treated separately. Moreover, plant growth and nutrient status varied in a non-linear manner with atmospheric CO2 concentration.

  19. Effects of different physical forms of concentrate on performance, carcass characteristics, and economic analysis in hanwoo steers

    OpenAIRE

    Kim, Sung Il; Seo, Bo cheon; Jang, In Surk; Kim, Ouk; Choi, Chang Bon; Jung, Keun Ki

    2014-01-01

    This study was performed to investigate the effects of different forms of concentrate fed to Hanwoo steers on performance, carcass characteristics, and economic performance. Forty-two Hanwoo steers (average age of 5.1 ± 0.8 mo. with body weight of 147.05 ± 10.85 kg) were randomly allotted into FC (animals fed flakes for entire experimental period) and GC (animals fed grounded concentrate during growing and fattening phases followed by flaked concentrate during finishing phase) groups for 758 ...

  20. Sediment concentration and bed form structures of Gulf of Cambay from remote sensing

    Digital Repository Service at National Institute of Oceanography (India)

    Kunte, P.D.

    of construction of pipelines. All these studies have been attempted either around the Gulf or the towards southern side of the GoC. The present study is focused on the estimation of sediment concentration and mapping of features observed using remote sensing...

  1. Vibronic coupling explains the ultrafast carotenoid-to-bacteriochlorophyll energy transfer in natural and artificial light harvesters.

    Science.gov (United States)

    Perlík, Václav; Seibt, Joachim; Cranston, Laura J; Cogdell, Richard J; Lincoln, Craig N; Savolainen, Janne; Šanda, František; Mančal, Tomáš; Hauer, Jürgen

    2015-06-01

    The initial energy transfer steps in photosynthesis occur on ultrafast timescales. We analyze the carotenoid to bacteriochlorophyll energy transfer in LH2 Marichromatium purpuratum as well as in an artificial light-harvesting dyad system by using transient grating and two-dimensional electronic spectroscopy with 10 fs time resolution. We find that Förster-type models reproduce the experimentally observed 60 fs transfer times, but overestimate coupling constants, which lead to a disagreement with both linear absorption and electronic 2D-spectra. We show that a vibronic model, which treats carotenoid vibrations on both electronic ground and excited states as part of the system's Hamiltonian, reproduces all measured quantities. Importantly, the vibronic model presented here can explain the fast energy transfer rates with only moderate coupling constants, which are in agreement with structure based calculations. Counterintuitively, the vibrational levels on the carotenoid electronic ground state play the central role in the excited state population transfer to bacteriochlorophyll; resonance between the donor-acceptor energy gap and the vibrational ground state energies is the physical basis of the ultrafast energy transfer rates in these systems. PMID:26049454

  2. Vibronic coupling explains the ultrafast carotenoid-to-bacteriochlorophyll energy transfer in natural and artificial light harvesters.

    Science.gov (United States)

    Perlík, Václav; Seibt, Joachim; Cranston, Laura J; Cogdell, Richard J; Lincoln, Craig N; Savolainen, Janne; Šanda, František; Mančal, Tomáš; Hauer, Jürgen

    2015-06-01

    The initial energy transfer steps in photosynthesis occur on ultrafast timescales. We analyze the carotenoid to bacteriochlorophyll energy transfer in LH2 Marichromatium purpuratum as well as in an artificial light-harvesting dyad system by using transient grating and two-dimensional electronic spectroscopy with 10 fs time resolution. We find that Förster-type models reproduce the experimentally observed 60 fs transfer times, but overestimate coupling constants, which lead to a disagreement with both linear absorption and electronic 2D-spectra. We show that a vibronic model, which treats carotenoid vibrations on both electronic ground and excited states as part of the system's Hamiltonian, reproduces all measured quantities. Importantly, the vibronic model presented here can explain the fast energy transfer rates with only moderate coupling constants, which are in agreement with structure based calculations. Counterintuitively, the vibrational levels on the carotenoid electronic ground state play the central role in the excited state population transfer to bacteriochlorophyll; resonance between the donor-acceptor energy gap and the vibrational ground state energies is the physical basis of the ultrafast energy transfer rates in these systems.

  3. Vibronic coupling explains the ultrafast carotenoid-to-bacteriochlorophyll energy transfer in natural and artificial light harvesters

    Energy Technology Data Exchange (ETDEWEB)

    Perlík, Václav; Seibt, Joachim; Šanda, František; Mančal, Tomáš [Institute of Physics, Faculty of Mathematics and Physics, Charles University in Prague, Ke Karlovu 5, Prague 121 16 (Czech Republic); Cranston, Laura J.; Cogdell, Richard J. [Institute of Molecular Cell and System Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow Biomedical Research Centre, 120 University Place, Glasgow G12 8TA, Scotland (United Kingdom); Lincoln, Craig N.; Hauer, Jürgen, E-mail: juergen.hauer@tuwien.ac.at [Photonics Institute, Vienna University of Technology, Gusshausstrasse 27, 1040 Vienna (Austria); Savolainen, Janne [Department of Physical Chemistry II, Ruhr-University Bochum, 44780 Bochum (Germany)

    2015-06-07

    The initial energy transfer steps in photosynthesis occur on ultrafast timescales. We analyze the carotenoid to bacteriochlorophyll energy transfer in LH2 Marichromatium purpuratum as well as in an artificial light-harvesting dyad system by using transient grating and two-dimensional electronic spectroscopy with 10 fs time resolution. We find that Förster-type models reproduce the experimentally observed 60 fs transfer times, but overestimate coupling constants, which lead to a disagreement with both linear absorption and electronic 2D-spectra. We show that a vibronic model, which treats carotenoid vibrations on both electronic ground and excited states as part of the system’s Hamiltonian, reproduces all measured quantities. Importantly, the vibronic model presented here can explain the fast energy transfer rates with only moderate coupling constants, which are in agreement with structure based calculations. Counterintuitively, the vibrational levels on the carotenoid electronic ground state play the central role in the excited state population transfer to bacteriochlorophyll; resonance between the donor-acceptor energy gap and the vibrational ground state energies is the physical basis of the ultrafast energy transfer rates in these systems.

  4. Blastomonas aquatica sp. nov., a bacteriochlorophyll-containing bacterium isolated from lake water.

    Science.gov (United States)

    Xiao, Na; Liu, Yongqin; Liu, Xiaobo; Gu, Zhengquan; Jiao, Nianzhi; Liu, Hongcan; Zhou, Yuguang; Shen, Liang

    2015-05-01

    Yellow or orange-to-brown pigmented, ovoid or rod-shaped, Gram-negative staining, aerobic strains PE 4-5(T) and N5-10 m-1 were isolated from brackish water in Lake Peng Co and fresh to brackish water in Lake Namtso on the Tibetan Plateau, China. Bacteriochlorophyll a was produced by the isolates. The predominant cellular fatty acids were C16 : 1, C17 : 1 and C18 : 1 unsaturated fatty acids, C17 : 1ω6c (55.3%), C17 : 1ω8c (13.0%) and C18 : 1ω7c (10.4%) for PE 4-5(T) and C18 : 1ω7c (54.7%) and C16 : 1ω7c (18.0%) for N5-10 m-1. The polar lipid profiles of strains PE 4-5(T) and N5-10 m-1 were composed of diphosphatidylglycerol, phosphatidylcholine (not detected in N5-10 m-1), phosphatidyldimethylethanolamine, phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylglycerol, sphingoglycolipid and an unknown phospholipid. The predominant respiratory quinone was ubiquinone Q10 and the DNA G+C content was 66.0 mol% for both strains. The16S rRNA gene sequence of strain PE 4-5(T) shared 99.0% similarity with that of N5-10 m-1, and 97.56% similarity with those of Blastomonas natatoria LMG 17322(T) and Blastomonas ursincola DSM 9006(T), respectively. The DNA-DNA hybridization relatedness between strains PE 4-5(T) and N5-10 m-1 was 79.0 ± 1.0%, but below 70% with the type strains in the genus Blastomonas . Based on the variability of phylogenetic and phenotypic characteristics, the isolates should be classified as representatives of a novel species of the genus Blastomonas; the name Blastomonas aquatica sp. nov. is proposed. The type strain is PE 4-5(T) ( =JCM 30179(T) =CGMCC 1.12851(T)). PMID:25724744

  5. Effect of HF Concentration on Physical and Electronic Properties of Electrochemically Formed Nanoporous Silicon

    Directory of Open Access Journals (Sweden)

    Pushpendra Kumar

    2009-01-01

    Full Text Available The most common fabrication technique of porous silicon (PS is electrochemical etching of a crystalline silicon wafer in a hydrofluoric (HF acid-based solution. The electrochemical process allows for precise control of the properties of PS such as thickness of the porous layer, porosity, and average pore diameter. The effect of HF concentration in the used electrolyte on physical and electronic properties of PS was studied by visual color observation, measuring nitrogen sorption isotherm, field emission type scanning electron microscopy, Raman spectroscopy, and photoluminescence spectroscopy. It was found that with decrease in HF concentration, the pore diameter increased. The PS sample with large pore diameter, that is, smaller nanocrystalline size of Si between the pores, was found to lead to a pronounced photoluminescence peak. The systematic rise of photoluminescence peak with increase of pore diameter and porosity of PS was attributed to quantum confinement. The changes in nanocrystalline porous silicon were also clearly observed by an asymmetric broadening and shift of the optical silicon phonons in Raman spectra. The change in electronic properties of PS with pore diameter suggests possibilities of use of PS material as a template for fundamental physics as well as an optical material for technological applications.

  6. Atomic absorption determination, in metal sulphide concentrates, of the elements that form gaseous hydrides

    International Nuclear Information System (INIS)

    An account is given of the investigational work on the determination of trace amounts of arsenic, antimony, bismuth, germanium, selenium, and tellurium by the technique using hydride generation and atomic-absorption spectrophotometry. The gaseous hydride is generated by reduction with sodium borohydride, and is subsequently swept by a flow of nitrogen into an air-entrained hydrogen-nitrogen flame. The generation equipment used is simple and inexpensive, and can be readily assembled in most laboratories. The optimum parameters were determined for each element. The effects of 31 probable interfering elements were investigated, and it was found that, although the majority did not interfere, severe interference was encountered when copper, nickel, and the noble metals were present. Methods for the elimination of copper and nickel were developed to allow the determination of arsenic, antimony, bismuth, selenium, and tellurium at the lower parts-per-million level in metal sulphide concentrates with an acceptable accuracy and precision. The determination of microgram amounts of germanium was found to be unsatisfactory

  7. concentration

    Directory of Open Access Journals (Sweden)

    Seth F. Oppenheimer

    1999-01-01

    Full Text Available We consider a model for biochemical oxygen demand (BOD in a semi-infinite river where the BOD is prescribed by a time varying function at the left endpoint. That is, we study the problem with a time varying boundary loading. We obtain the well-posedness for the model when the boundary loading is smooth in time. We also obtain various qualitative results such as ordering, positivity, and boundedness. Of greatest interest, we show that a periodic loading function admits a unique asymptotically attracting periodic solution. For non-smooth loading functions, we obtain weak solutions. Finally, for certain special cases, we show how to obtain explicit solutions in the form of infinite series.

  8. Prediction and analysis of near-road concentrations using a reduced-form emission/dispersion model

    Directory of Open Access Journals (Sweden)

    Kononowech Robert

    2010-06-01

    Full Text Available Abstract Background Near-road exposures of traffic-related air pollutants have been receiving increased attention due to evidence linking emissions from high-traffic roadways to adverse health outcomes. To date, most epidemiological and risk analyses have utilized simple but crude exposure indicators, most typically proximity measures, such as the distance between freeways and residences, to represent air quality impacts from traffic. This paper derives and analyzes a simplified microscale simulation model designed to predict short- (hourly to long-term (annual average pollutant concentrations near roads. Sensitivity analyses and case studies are used to highlight issues in predicting near-road exposures. Methods Process-based simulation models using a computationally efficient reduced-form response surface structure and a minimum number of inputs integrate the major determinants of air pollution exposures: traffic volume and vehicle emissions, meteorology, and receptor location. We identify the most influential variables and then derive a set of multiplicative submodels that match predictions from "parent" models MOBILE6.2 and CALINE4. The assembled model is applied to two case studies in the Detroit, Michigan area. The first predicts carbon monoxide (CO concentrations at a monitoring site near a freeway. The second predicts CO and PM2.5 concentrations in a dense receptor grid over a 1 km2 area around the intersection of two major roads. We analyze the spatial and temporal patterns of pollutant concentration predictions. Results Predicted CO concentrations showed reasonable agreement with annual average and 24-hour measurements, e.g., 59% of the 24-hr predictions were within a factor of two of observations in the warmer months when CO emissions are more consistent. The highest concentrations of both CO and PM2.5 were predicted to occur near intersections and downwind of major roads during periods of unfavorable meteorology (e.g., low wind

  9. Vibronic coupling explains the ultrafast carotenoid-to-bacteriochlorophyll energy transfer in natural and artificial light harvesters

    CERN Document Server

    Perlík, Václav; Cranston, Laura J; Cogdell, Richard J; Lincoln, Craig N; Savolainen, Janne; Šanda, František; Mančal, Tomáš; Hauer, Jürgen

    2015-01-01

    The initial energy transfer in photosynthesis occurs between the light-harvesting pigments and on ultrafast timescales. We analyze the carotenoid to bacteriochlorophyll energy transfer in LH2 Marichromatium purpuratum as well as in an artificial light-harvesting dyad system by using transient grating and two-dimensional electronic spectroscopy with 10 fs time resolution. We find that F\\"orster-type models reproduce the experimentally observed 60 fs transfer times, but overestimate coupling constants, which leads to a disagreement with both linear absorption and electronic 2D-spectra. We show that a vibronic model, which treats carotenoid vibrations on both electronic ground and excited state as part of the system's Hamiltonian, reproduces all measured quantities. Importantly, the vibronic model presented here can explain the fast energy transfer rates with only moderate coupling constants, which are in agreement with structure based calculations. Counterintuitively, the vibrational levels on the carotenoid el...

  10. Effective closed form mathematical approach to determine kinetic constants of NR vulcanized with sulphur and accelerators at different concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Milani, Gabriele, E-mail: milani@stru.polimi.it, E-mail: gabriele.milani@polimi.it [Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan (Italy); Hanel, Thomas; Donetti, Raffaella [Pirelli Tyre, Via Alberto e Piero Pirelli 25, 20126 Milan (Italy); Milani, Federico [CHEMCO Consultant, Via J.F. Kennedy 2, 45030 Occhiobello (Italy)

    2015-03-10

    The basic reaction scheme due to Han and co-workers for NR vulcanized with sulphur is adopted and modified taking into account the single contributions of the different accelerators, focusing in particular on some experimental data ad hoc obtained at Pirelli’s laboratories, where NR was vulcanized at different temperatures (from 150 to 180 °C) and concentrations of sulphur, using TBBS and DPG in the mixture as co-agents. Typically, the chain reactions are initiated by the formation of macro-compounds that are responsible of the formation of the unmatured crosslinked polymer. This first reaction depends on the reciprocal concentrations of all components and their chemical nature. In presence of two accelerators, it was considered that the reactions between each single accelerator and the NR raw material occur in parallel, making the reasonable assumption that there are no mutual reactions between the two accelerators. From the kinetic scheme adopted, a closed form solution was found for the crosslink density, with the only limitation that the induction period is excluded from computations. Even kinetic constants are evaluated in closed form, avoiding a numerically demanding least-squares best fitting on rheometer experimental data. Two series of experiments available, relying into rheometer curves at different temperatures and different concentrations of sulphur and accelerator, are utilized to evaluate the fitting capabilities of the mathematical model. Very good agreement between numerical output and experimental data is experienced in all cases analysed.

  11. The effect of C atom concentration on the electronic properties of boron carbonitride alloy nanotube in zig-zag form

    Indian Academy of Sciences (India)

    H Milani Moghaddam

    2011-06-01

    Electronic properties of single-walled boron nitride nanotube in zig-zag form are numerically investigated by replacing B atoms with C atoms. Using a tight-binding Hamiltonian, the methods based on Green’s function theory, Landauer formalism and Dyson equation, the electronic density of states and electronic conductance in boron nitride nanotube and boron carbonitride nanotube are calculated. Our calculations indicate that in a boron nitride nanotube, the localized states associated with C impurities appear as the concentration of C atoms increases. The boron carbonitride nanotube thus behaves like a semiconductor. Also, by increasing the C atom concentration, the voltage in the first step on the – characteristics decreases, whereas the corresponding current increases.

  12. Phosphorus Concentration and Forms in Surface and Subsurface Drainage Water from Wetland Rice Fields in the Shaoxing Plain

    Institute of Scientific and Technical Information of China (English)

    ZHANG MINGKUI; JIANG HONG; LIU XINGMEI

    2003-01-01

    Phosphorus (P) is the limiting factor for eutrophication in most freshwater ecosystems. In China, Ptransported from intensively cultivated land has been reported as an important source of P in surface waters.In this study, we investigated P concentration and forms in surface and subsurface drainage from wetland ricefields in the Shaoxing plain, Zhejiang Province, China. From selected rice fields, surface drainage sampleswere collected at rice-growing, non-growing and fertilization periods, and subsurface drainage samples atdrought and rewetting (irrigation or precipitation after 5~10 d drought period in the surface soils) and wet(drainage under long-term wet soil condition) periods. Water samples were characterized for their totalreactive P (TRP), dissolved reactive P (DRP) and particulate reactive P (PRP). Concentrations of the TRPand DRP in the surface drainage ranged from 0.08 to 1.50 and 0.06 to 1.27 mg L-1, respectively. The TRPand DRP were dependent on field operation activities, and decreased in the order of fertilization period >rice-growing period > non-growing period. Phosphorus concentration of runoff receiving P fertilizer can bean environmental concern. The PRP concentration in the surface drainage, ranging from 0.01 to 0.57 mgL-1, accounted for 8%~78% of the TRP. Concentration of the TRP in the subsurface drainage was from0.026 to 0.090 mg L-1, consisting of 29%~90 % of the DRP and 10%~71% of the PRP. In the droughtand rewetting period, the PRP accounted for, on average, 63% of the TRP, much higher than in the wetperiod (23%), suggesting that there was transport of P in preferential flow during drainage events after ashort-term drought period in the surface soils. Therefore, P losses in particulate form may be importantin the subsurface drainage from rice fields when surface soils form cracks and favor rapid flow downwardthrough the soil profiles, suggesting the important role of water-dispersible colloid particles in mediating andco

  13. Effects of different physical forms of concentrate on performance, carcass characteristics, and economic analysis in hanwoo steers.

    Science.gov (United States)

    Kim, Sung Il; Seo, Bo Cheon; Jang, In Surk; Kim, Ouk; Choi, Chang Bon; Jung, Keun Ki

    2014-01-01

    This study was performed to investigate the effects of different forms of concentrate fed to Hanwoo steers on performance, carcass characteristics, and economic performance. Forty-two Hanwoo steers (average age of 5.1 ± 0.8 mo. with body weight of 147.05 ± 10.85 kg) were randomly allotted into FC (animals fed flakes for entire experimental period) and GC (animals fed grounded concentrate during growing and fattening phases followed by flaked concentrate during finishing phase) groups for 758 d after reaching an age of 30.0 ± 0.82 mo. There was no difference in body weight (BW) or ADG between the treatments until fattening (15 ~ 22 mo.) phase. However, by finishing phase (23 ~ 30 mo.), the GC group (739.24 kg BW and 0.67 kg ADG) showed greater (P meat quality grade were 14.0 and 48.0% higher in the GC group compared to the FC group. There was no significant difference in physicochemical characteristics, including moisture and crude protein levels, between the treatments. Gross income per head excluding operating expenses was 59.3% greater in the GC group (1,647,512 won) compared to the FC group (1,034,343 won). PMID:26290698

  14. [Concentration and form of asbestos fibers in tap drinking water contaminated from a water supply pipe with asbestos-cement].

    Science.gov (United States)

    Saitoh, K; Takizawa, Y; Muto, H; Hirano, K

    1992-10-01

    The identification and concentration of asbestos fibers in tap drinking water supplied in a central area of Akita Prefecture, Japan, were determined by phase-contrast microscopy and a scanning electron microscope equipped with an energy-dispersive X-ray microanalyzer. The following results were obtained. 1. Asbestos fibers were found in the tap water from two areas in which an asbestos-cement pipe was used for public water supply. The concentrations of asbestos fibers in the tap water were 2.7 x 10(4) to 27.0 x 10(4) fibers per liter of water in area A and 10.0 x 10(4) to 21.0 x 10(4) in area B. On the other hand, no asbestos fiber contamination was observed in tap water of area C, which shared a common water source with area A. A vinyl chloride pipe was used over the entire length of the water supply in route C. 2. Crocidolite was the predominant type of asbestos fiber detected in the tap water. Chrysotile and a mixture of chrysotile and amosite were also observed. 3. Almost all asbestos fibers detected in the tap water possessed the form of thick or sheaved fibers with lengths ranging from ca. 5 to 10 microns. Their shapes were very different from those of asbestos fibers found in the atmosphere. The typical form of the latter is short (ca. 1 micron in length) and needle-like. 4. It was suggested that the contamination of asbestos fibers in the tap water was caused by erosion and peeling off of the inner wall of the asbestos-cement pipe used as a conduit. In order to evaluate the safety of drinking water in Japan, an extensive survey on asbestos-fiber contamination in tap water is necessary. PMID:1464953

  15. Changes in the salinity tolerance of sweet pepper plants as affected by nitrogen form and high CO2 concentration.

    Science.gov (United States)

    Piñero, María C; Pérez-Jiménez, Margarita; López-Marín, Josefa; Del Amor, Francisco M

    2016-08-01

    The assimilation and availability of nitrogen in its different forms can significantly affect the response of primary productivity under the current atmospheric alteration and soil degradation. An elevated CO2 concentration (e[CO2]) triggers changes in the efficiency and efficacy of photosynthetic processes, water use and product yield, the plant response to stress being altered with respect to ambient CO2 conditions (a[CO2]). Additionally, NH4(+) has been related to improved plant responses to stress, considering both energy efficiency in N-assimilation and the overcoming of the inhibition of photorespiration at e[CO2]. Therefore, the aim of this work was to determine the response of sweet pepper plants (Capsicum annuum L.) receiving an additional supply of NH4(+) (90/10 NO3(-)/NH4(+)) to salinity stress (60mM NaCl) under a[CO2] (400μmolmol(-1)) or e[CO2] (800μmolmol(-1)). Salt-stressed plants grown at e[CO2] showed DW accumulation similar to that of the non-stressed plants at a[CO2]. The supply of NH4(+) reduced growth at e[CO2] when salinity was imposed. Moreover, NH4(+) differentially affected the stomatal conductance and water use efficiency and the leaf Cl(-), K(+), and Na(+) concentrations, but the extent of the effects was influenced by the [CO2]. An antioxidant-related response was prompted by salinity, the total phenolics and proline concentrations being reduced by NH4(+) at e[CO2]. Our results show that the effect of NH4(+) on plant salinity tolerance should be globally re-evaluated as e[CO2] can significantly alter the response, when compared with previous studies at a[CO2]. PMID:27317970

  16. [Photosynthetic activity and components of the electron transport chain in the aerobic bacteriochlorophyll A-containing bacterium Roseinatronobacter thiooxidans].

    Science.gov (United States)

    Stadnichuk, I N; Ianiushin, M F; Boĭchenko, V A; Lukashev, E P; Boldareva, E N; Solov'ev, A A; Gorlenko, V M

    2009-01-01

    Bioenergetics of the aerobic bacteriochlorophyll a-containing (BCl a) bacterium (ABC bacterium) Roseinatronobacter thiooxidans is a combination of photosynthesis, oxygen respiration, and oxidation of sulfur compounds under alkaliphilic conditions. The photosynthetic activity of Rna. thiooxidans cells was established by the photoinhibition of cell respiration and reversible photobleaching discoloration of the BCl a of reaction centers (RC), connected by the chain of electron transfer with cytochrome c551 oxidation. The species under study, like many purple bacteria and some of the known ABC bacteria, possesses a light-harvesting pigment-protein (LHI) complex with the average number of 30 molecules of antenna BCl a per one photosynthetic RC. Under microaerobic growth conditions, the cells contained bc1 complex and two terminal oxidases: cbb3-cytochrome oxidase and the alternative cytochrome oxidase of the a3 type. Besides, Rna. thiooxidans was shown to have several different soluble low- and high-potential cytochromes c, probably associated with the ability of utilizing sulfur compounds as additional electron donors.

  17. Studies on the concentration and mination of radiocobalt in organic complexed and ionic forms by mussel, Mytilisepta virgatus

    International Nuclear Information System (INIS)

    Paper electrophoretic behavior of cobalt in sea water media with or without glycine was investigated under laboratory conditions. No detectable change in the apparent electrophoretic mobility of synthesized trisglycinato cobalt (III) complex in a simple sea water medium was observed during the ageing period of 41 days under cintinuous aeration at 15 +- 20C. Cobaltous ion in a sea water medium without glycine was hydrolyzed and diffuse electrophoretic zone was observed with ageing. The uptake and elimination of the different chemical forms of radiocobalt by mussel, Mytilisepta virgatus, were studied under laboratory conditions. The synthesized 57Co-trisglycinate and 60Co in cobalt chloride were used as tracers for organic complexed and ionic cobalt, respectively. The rates of uptake, the turnover rates and the concentration factors for organic cobalt in both the soft parts and the shell of mussel were smaller than those for ionic cobalt from the analysis based on the exponential model. In the uptake experiments, the exchanged cobalt in the soft parts of mussel could be calculated to be 0.26% for organic cobalt and 1.93% for ionic cobalt at equilibrium state, respectively. The whole-body retention curves of both radiocobalt consisted of at least the two components. The initial elimination of organic cobalt was larger than that of ionic cobalt. Mass balance calculations at the conclusion of the uptake experiments showed a remarkable difference between the distributions of organic and ionic cobalt in the systems. (J.P.N.)

  18. The nature of coherences in the B820 bacteriochlorophyll dimer revealed by two-dimensional electronic spectroscopy.

    Science.gov (United States)

    Ferretti, Marco; Novoderezhkin, Vladimir I; Romero, Elisabet; Augulis, Ramunas; Pandit, Anjali; Zigmantas, Donatas; van Grondelle, Rienk

    2014-06-01

    Light-harvesting in photosynthesis is determined by the excitonic interactions in disordered antennae and the coupling of collective electronic excitations to fast nuclear motions, producing efficient energy transfer with a complicated interplay between exciton and vibrational coherences. Two-dimensional electronic spectroscopy (2DES) is a powerful tool to study the presence of these coherences in photosynthetic complexes. However, the unambiguous assignment of the nature of the observed coherences is still under debate. In this paper we apply 2DES to an excitonically coupled bacteriochlorophyll dimer, the B820 subunit of the light harvesting complex 1 (LH1-RC) of R. rubrum G9. Fourier analysis of the measured kinetics and modeling of the spectral responses in a complete basis of electronic and vibrational states allow us to distinguish between pure vibrational, mixed exciton-vibrational (vibronic), and predominantly exciton coherences. The mixed coherences have been found in a wide range of oscillation frequencies, whereas exciton coherences give the biggest contributions for the frequencies in the 400-550 cm(-1) range, corresponding to the exciton splitting energy of the B820 dimer. Significant exciton coherences are also present at higher frequencies, i.e., up to 800 cm(-1), which are determined by realizations of the disorder with a large energy gap between the two pigments (which increases the apparent value of the exciton splitting). Although the B820 dimer is a model system, the approach presented here represents a basis for further analyses of more complicated systems, providing a tool for studying the interplay between electronic and vibrational coherences in disordered photosynthetic antennae and reaction centres. PMID:24430275

  19. On the biphoton excitation of the fluorescence of the bacteriochlorophyll molecules of purple photosynthetic bacteria by powerful near IR femto-picosecond pulses

    International Nuclear Information System (INIS)

    The authors of a number of experimental works detected nonresonance biphoton excitation of bacteriochlorophyll molecules, which represent the main pigment in the light-absorbing natural “antenna” complexes of photosynthesizing purple bacteria, by femtosecond IR pulses (1250–1500 nm). They believe that IR quanta excite hypothetic forbidden levels of the pigments of these bacteria in the double frequency range 625–750 nm. We propose and ground an alternative triplet mechanism to describe this phenomenon. According to our hypothesis, the mechanism of biphoton excitation of molecules by IR quanta can manifest itself specifically, through high triplet levels of molecules in the high fields induced by femtosecond-picosecond laser pulses.

  20. Impacts of anthropic pressures on soil phosphorus availability, concentration, and phosphorus forms in sediments in a Southern Brazilian watershed

    Energy Technology Data Exchange (ETDEWEB)

    Pellegrini, Joao Batista Rossetto; Rheinheimer dos Santos, Danilo; Goncalves, Celso Santos; Copetti, Andre Carlos Cruz [Dept. de Solos, Univ. Federal de Santa Maria, Centro de Ciencias Rurais, Santa Maria, RS (Brazil); Bortoluzzi, Edson Campanhola [Faculdade de Agronomia e Medicina Veterinaria da Univ. de Passo Fundo, RS (Brazil); Tessier, Daniel [Inst. National de la Recherche Agronomique, Versailles (France)

    2010-04-15

    Purpose: The transfer of soil sediments and phosphorus from terrestrial to aquatic systems is a common process in agricultural lands. The aims of this paper are to quantify the soil phosphorus availability and to characterize phosphorus forms in soil sediments as contaminant agents of waters as a function of anthropic pressures. Materials and methods On three subwatersheds with different anthropic pressure, water and sediment samples were collected automatically in upstream and downstream discharge points in six rainfall events during the tobacco growing season. Phosphorus desorption capacity from soil sediments was estimated by successive extractions with anion exchange resins. First-order kinetic models were adjusted to desorption curves for estimating potentially bioavailable particulate phosphorus, desorption rate constant, and bioavailable particulate phosphorus. Results and discussion The amount of bioavailable particulate phosphorus was directly correlated with the iron oxide content. The value of desorption rate constant was directly related with the total organic carbon and inversely with the iron oxide contents. Phosphate ions were released to solution, on average, twice as rapidly from sediments collected in subwatersheds with low anthropic activity than from those ones of highly anthropic subwatersheds. Anthropic pressure on watershed can engender high sediment discharge, but these solid particles seem to present low phosphorus-releasing capacity to water during transport due to the evidenced high affinity between phosphorus and iron oxide from sediments. Conclusions Anthropic pressure was related with sediment concentration and phosphorus release to aquatic systems. While natural vegetation along streams plays a role on soil and water depuration, it is unable to eliminate the phosphorus inputs intrinsic to the agricultural-intensive systems. Recommendations and perspectives The contamination of water in watershed by phosphates is facilitated by the

  1. Xylem sap collection and extraction methodologies to determine in vivo concentrations of ABA and its bound forms by gas chromatography-mass spectrometry (GC-MS

    Directory of Open Access Journals (Sweden)

    Netting Andrew G

    2012-03-01

    Full Text Available Abstract Background Accurate quantification of xylem sap ABA concentrations is important to underpin models of root-to-shoot ABA signalling to predict the physiological effects of soil drying. Growing tomato plants in a whole plant pressure chamber allowed sequential xylem sap collection from a detached leaf, the petiole stub of an otherwise intact plant and finally the de-topped root system of the same plant, to determine the impact of xylem sap sampling methodology on xylem ABA concentration. Since xylem sap can contain bound forms of ABA, a novel gas chromatography-mass spectrometry (GC-MS procedure was developed to chemically separate free ABA from two in planta bound ABA forms known as Adducts I and II and ABA-glucose-ester (ABA-GE. Results Xylem sap ABA concentrations were highly dependent on the sampling methodology used: the highest concentrations were detected in sap collected by applying an overpressure to detached leaves following the measurement of leaf water potential. Irrespective of xylem sap source, the wild-type cultivars Ailsa Craig and Rheinlands Ruhm had higher free ABA concentrations than a range of ABA-deficient mutants (notabilis, flacca and sitiens. However, in the mutants, concentrations of bound forms of ABA were similar to wild-type plants, and similar to free ABA concentrations. Conclusions Although xylem concentrations of these bound ABA forms and ABA-GE suggest they have a limited physiological impact on ABA homeostasis in tomato, the methods developed here will allow a more complete understanding of ABA biochemistry and root-to-shoot signalling in species known to have higher concentrations of these compounds.

  2. Evaluation of Disinfection Byproducts Formed from the Chlorination of Lyophilized and Reconstituted NOM Concentrate from a Drinking Water Source - Poster

    Science.gov (United States)

    Drinking water treatment and disinfection byproduct (DBP) research can be complicated by difficulties in shipping large water quantities and NOM geographical and temporal variability. Access to a drinking water representative, shelf-stable, concentrated NOM source would solve th...

  3. Evaluation of Disinfection Byproducts formed from the Chlorination of Lyophilized and Reconstituted NOM Concentrate from a Drinking Water Source

    Science.gov (United States)

    Drinking water treatment and disinfection byproduct (DBP) research can be complicated by difficulties in shipping large water quantities and NOM geographical and temporal variability. Access to a drinking water representative, shelf-stable, concentrated NOM source would solve th...

  4. Variation in concentrations of three mercury (Hg) forms at a rural and a suburban site in New York State.

    Science.gov (United States)

    Choi, Hyun-Deok; Huang, Jiaoyan; Mondal, Sumona; Holsen, Thomas M

    2013-03-15

    Tekran® Hg speciation systems were used at a rural site (Huntington Forest, NY; HF) and a suburban site (Rochester, NY; ROC) to measure gaseous elemental mercury (GEM), gaseous oxidized mercury (GOM), and fine particulate-bound mercury (PBM2.5) concentrations for two years (December 2007 to November 2009). Ancillary data were also available from the New York State Department of Environmental Conservation and the United States Environmental Protection Agency Clean Air Status and Trends Network. Seasonal GEM concentrations were similar at both sites and influenced by factors such as the planet boundary layer (PBL) height and mercury emissions from snow, soil, and point sources. In some seasons, O3 was negatively correlated with GEM at ROC and positively correlated with GEM at HF. At HF, O3 was correlated with GOM and was typically higher in the afternoon. The cause of this pattern may be photochemical reactions during the day, and the GOM diel pattern may also be due to deposition which is enhanced by dew formation during the night and early morning. PBM2.5 concentrations were higher in winter at both sites. This is indicative of local wood combustion for space heating in winter, increased sorption to particles at lower temperatures, and lower PBL in the winter. At the suburban site, 2 of 12 events with enhanced GEM/CO ratios were poorly correlated with SO2/GOM, implying that these two events were due either to long range transport or regional metallurgical industries in Canada. PMID:22959656

  5. Spectroscopic properties of a reconstituted light-harvesting complex from the green sulfur bacterium Chlorobium tepidum containing CsmA and bacteriochlorophyll a

    DEFF Research Database (Denmark)

    Pedersen, Marie Østergaard; Pham, Lan; Steensgaard, Dorte Bjerre;

    2008-01-01

    Green sulfur bacteria possess two light-harvesting antenna systems, the chlorosome and the Fenna-Matthews-Olson (FMO) protein. In addition to self-aggregated bacteriochlorophyll (BChl) c, chlorosomes of Chlorobium tepidum contain a small amount of BChl a (ratio 100:1). The chlorosomal BChl a is a...

  6. Evidence for the complex relationship between free amino acid and sugar concentrations and acrylamide-forming potential in potato

    OpenAIRE

    Muttucumaru, N.; Powers, S. J.; Elmore, J. S.; Briddon, A; Mottram, D. S.; Halford, N. G.

    2014-01-01

    Free amino acids and reducing sugars participate in the Maillard reaction during high-temperature cooking and processing. This results not only in the formation of colour, aroma and flavour compounds, but also undesirable contaminants, including acrylamide, which forms when the amino acid that participates in the reaction is asparagine. In this study, tubers of 13 varieties of potato (Solanum tuberosum), which had been produced in a field trial in 2010 and sampled immediately after harvest or...

  7. EFFECTS OF ARSENIC CONCENTRATIONS AND FORMS ON GROWTH AND ARSENIC UPTAKE AND ACCUMULATION BY INDIAN MUSTARD (BRASSICA JUNCEA L. GENOTYPES

    Directory of Open Access Journals (Sweden)

    INDIRA CHATURVEDI

    2006-10-01

    Full Text Available By using two Brassica juncea genotypes (Varuna and DHR-9504 a green house experiment was carried out during crop cycle (2003-2004, at Agricultural Farm, Bilaspur, Chhattisgarh, India. In Indian mustard, arsenic extraction by plants increased signifi cantly with increasing arsenic concentrations in soils. Uptake of arsenite by Indian mustard genotypes was higher than that of arsenate. Stunted growth of the plants was also observed in this study. This experiment clearly demonstrated the existence of genotypical variations in tolerance to As toxicity among Brassica juncea genotypes.

  8. Influence of the concentration of water-soluble polyelectrolytes on the kinetics of flocculation of kaolin suspension and strength of formed floccules

    Directory of Open Access Journals (Sweden)

    R. Taubaeva

    2013-05-01

    Full Text Available The influence of the concentration and the charge of water-soluble (WS polyelectrolytes on the kinetics aggregation of particles kaolin was investigated. It is shown that with the alternation of slow and fast mixing result to the formation of large and strong flocs. The rate of aggregation and size of particles formed flocs increases with the concentration of the reagent and the charge density of the polyelectrolyte. It was found that at low concentrations (10-5~2,5·10-3% polyelectrolytes (cationic - Zetag 89, Zetag 92, anionic - Magnafloc 155, Magnafloc 156 flocculants flocculation of  kaolin suspensions increases and the higher concentrations of flocculants (more on 2,5·10-3% - suspension of kaolin is stabilized.

  9. Concentrations and chemical forms of potentially toxic metals in road-deposited sediments from different zones of Hangzhou, China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Mingkui; WANG Hao

    2009-01-01

    The 25 road-deposited sediments were collected from five different land-use zones (industrial, residential, commercial, park, and countryside) in Hangzhou, China. The concentrations of metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in these samples were determined using the ICP-AES after digestion with the mixture of HNO3-HF-HCl (aqua regia), and chemically fractionated using the modified BCR (the European Community Bureau of Reference) sequential extraction procedure. The highest metal concentration level was detected in the sample from industrial zone and commercial zone having heavy traffic. While the lowest metal level was noted in the street dust sample from residential zone, park, and countryside zone. The mobility sequence based on the sum of the BCR sequential extraction stages was: Zn (80.28%), Pb (78.68%), Cd (77.66%) > Cu (73.34%) > Mn (67.92%) > Co (41.66%) > Ni (30.36%) > Cr (21.56%), Fe (20.86%). Correlation analysis and principal component analysis were applied to the data matrix to evaluate the analytical results and to identify the possible pollution sources of metals. Factor analysis showed that these areas were mainly contaminated by three sources, namely lithology, traffic, and industry.

  10. Concentration and Transport of Nitrate by the Mat-Forming Sulfur Bacterium Thioploca Rid E-1821-2011

    DEFF Research Database (Denmark)

    FOSSING, H.; GALLARDO, VA; JØRGENSEN, BB;

    1995-01-01

    MARINE species of Thioploca occur over 3,000 km along the continental shelf off Southern Peru and North and Central Chile(1-4). These filamentous bacteria live in bundles surrounded by a common sheath and form thick mats on the sea floor under the oxygen-minimum zone in the upwelling region, at b...... this nitrate 5-10 cm down into the sediment and reduce it, with concomitant oxidation of hydrogen sulphide, thereby coupling the nitrogen and sulphur cycles in the sediment....

  11. Simulation of nitrate-concentration variation and estimation of nitrogen-form transformation in groundwater by modified rain-runoff model

    Science.gov (United States)

    Hong, N.; Hama, T.; Suenaga, Y.; Huang, X.; Wei, Q.; Kawagoshi, Y.

    2015-12-01

    Groundwater is an important drinking-water source throughout the world. Nitrate is considered as one of the most widespread contaminant in groundwater and some studies have presented that intake of excess amount of nitrate could be associated with several types of disease. Modeling of nitrate-concentration in groundwater and estimation of nitrogen-form transformation by meteorological effects is necessary for countermeasure to nitrate contamination in groundwater. In this research, groundwater-quality tank model (GQTM) coupled with Fuzzy Optimize Method (FOM) and Shuffled Complex Evolution-University of Arizona (SCE-UA) is proposed to simulate NO3- and Cl- concentrations simultaneously. For the simulation, daily precipitation data and weekly data of NO3- and Cl- concentrations at two observation wells in Kumamoto City for three years (2012-2015) were used. The GQTM coupled with FOM and SCE-UA algorithm provided accurate simulation results in the variations of NO3- and Cl- concentrations. Difference in the concentration-variation ratio between NO3- and Cl- suggested that NO3- concentration variation was mainly due to dilution and concentration processes rather than nitrogen transformation by nitrification-denitrification reaction in the both observation wells. This calculation provides a simple and reliable method in nitrification and denitrification process estimation. The GQTM coupled with FOM and SCE-UA must be useful for managing of groundwater supplies in effective and sustainable manner by providing scientific evidence for the risk of groundwater quality.

  12. Study of Falling Roof Vibrations in a Production Face at Roof Support Resistance in the Form of Concentrated Force

    Science.gov (United States)

    Buyalich, G. D.; Buyalich, K. G.; Umrikhina, V. Yu

    2016-08-01

    One of the main reasons of roof support failures in production faces is mismatch of their parameters and parameters of dynamic impact on the metal structure from the falling roof during its secondary convergences. To assess the parameters of vibrational interaction of roof support with the roof, it was suggested to use computational models of forces application and a partial differential equation of fourth order describing this process, its numerical solution allowed to assess frequency, amplitude and speed of roof strata movement depending on physical and mechanical properties of the roof strata as well as on load bearing and geometry parameters of the roof support. To simplify solving of the differential equation, roof support response was taken as the concentrated force.

  13. On the biphoton excitation of the fluorescence of the bacteriochlorophyll molecules of purple photosynthetic bacteria by powerful near IR femto-picosecond pulses

    Energy Technology Data Exchange (ETDEWEB)

    Borisov, A. Yu., E-mail: borissov@belozersky.msu.ru [Moscow State University, Belozersky Institute of Physicochemical Biology (Russian Federation)

    2011-11-15

    The authors of a number of experimental works detected nonresonance biphoton excitation of bacteriochlorophyll molecules, which represent the main pigment in the light-absorbing natural 'antenna' complexes of photosynthesizing purple bacteria, by femtosecond IR pulses (1250-1500 nm). They believe that IR quanta excite hypothetic forbidden levels of the pigments of these bacteria in the double frequency range 625-750 nm. We propose and ground an alternative triplet mechanism to describe this phenomenon. According to our hypothesis, the mechanism of biphoton excitation of molecules by IR quanta can manifest itself specifically, through high triplet levels of molecules in the high fields induced by femtosecond-picosecond laser pulses.

  14. 水合物溶液分离技术研究进展%Progress in aqueous solution concentration by forming clathrate hydrate

    Institute of Scientific and Technical Information of China (English)

    李士凤; 谭哲; 申延明; 刘东斌; 樊丽辉; 白净

    2014-01-01

    水合物法溶液分离是一种新兴的分离技术。本文概述了水合物溶液分离技术的基本原理,指出水合物溶液分离技术的优缺点。重点回顾了水合物溶液分离技术在海水淡化、废水处理、果汁浓缩、生化分离等过程中的研究进展:尽管水合物海水淡化已经有工业化的报道,但是水合物生成压力较高,分离过程能耗较大,阻碍了该技术的推广应用;水合物法废水处理仅局限于制浆废水回收方面;水合物果汁浓缩以及生化分离方面的研究表明水合物法对于高附加值产品分离十分有效。分析表明,水合物溶液分离技术在上述应用过程中存在水合物生成压力大、水合物结晶夹带浓缩液等问题,指出未来水合物溶液分离技术的研究方向为寻找更加有效的水合物生成气体以及在高附加值产品分离回收过程中的应用。%The hydrate-based solution separation is a novel separation technology. This paper summarized the basic principle of aqueous concentration by forming hydrate,the benefits and drawbacks of hydrate technology. This paper emphasized the progress of seawater desalination, wastewater treatment,juice concentration,and biochemical separation by forming clathrate hydrate. Although forming hydrate desalination has been industrialized,the high and energy consumption of hydrate formation pressure limited its applications. The research on waste water treatment was only limited to pulping waste water recovery. Juice concentration and biochemical separation by forming hydrate were proven to be effective in recovery products with high added-value. The problems of high pressure of hydrate formation and hydrate crystal entrained concentrated solution by forming clathrate hydrate were also discussed. Future research directions of aqueous solution concentration by forming hydrate were proposed.

  15. Study of the effect of magnesium concentration on the deposit of allotropic forms of calcium carbonate and related carbon steel interface behavior

    Energy Technology Data Exchange (ETDEWEB)

    Ben Amor, Y., E-mail: yasser_ben@yahoo.f [Institut Superieur des Sciences et Technologies de l' Environnement de Borj-Cedria, B.P 1003, Hammam-Lif 2050 (Tunisia); Bousselmi, L. [Laboratoire Traitement et Recyclage des Eaux, B.P 273, Hammam-Lif, Technopole de Borj-Cedria, 8020 Soliman (Tunisia); Tribollet, B. [UPR 15 CNRS - Physique des liquides et Electrochimie, Universite Pierre et Marie Curie - Tour 22, 4 place Jussieu, 75252 Paris Cedex 05 (France); Triki, E. [Unite de recherche Corrosion et Protection des metalliques, Ecole Nationale d' Ingenieurs de Tunis, P.B. 37, 1002 Tunis, Belvedere (Tunisia)

    2010-06-30

    Different allotropic forms of calcium carbonate scales were electrochemically deposited on a carbon steel surface in artificial underground Tunisian water at -0.95 V{sub SCE} and various Mg{sup 2+} concentrations. Because of the importance of the diffusion process, the rotating disk electrode was used. The deposition kinetics were analyzed by chronoamperometry measurements and the calcareous layers were characterized by electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). The physical model proposed by Gabrielli was used to analyze the EIS measurements. Independent of the deposited allotropic form of calcium carbonate, the measurements showed that the oxygen reduction occurs in the pores formed between the CaCO{sub 3} crystals and the metallic surface.

  16. [Effects of Different Modifier Concentrations on Lead-Zinc Tolerance, Subcellular Distribution and Chemical Forms for Four Kinds of Woody Plants].

    Science.gov (United States)

    Chen, Yong-hua; Zhang, Fu-yun; Wu, Xiao-fu; Liang, Xi; Yuan, Si-wen

    2015-10-01

    Four kinds of lead-zinc tolerant woody plants: Nerium oleander, Koelreuteria paniculata, Paulownia and Boehmeria were used as materials to estimate their enrichment and transferable capacity of lead (Pb) and zinc (Zn) and analyze the subcellular distribution and chemical speciation of Zn and Ph in different parts of plants, under different modifier concentrations (CK group: 100% lead-zinc slag plus a small amount of phosphate fertilizer, improved one: 85% of lead-zinc slag ± 10% peat ± 5% bacterial manure plus a small amount of phosphate fertilizer, improved two: 75% lead-zinc slag ± 20% peat ± 5% bacterial manure ± a small amount of phosphate). Results showed that: (1) The content of Pb, Zn in matrix after planting four kinds of plants was lower than before, no significant difference between improved one and improved two of Nerium oleander and Boehmeria was found, but improved two was better than improved one of Paulownia, while improved one was better than improved two of Koelreuteria paniculata; Four plants had relatively low aboveground enrichment coefficient of Pb and Zn, but had a high transfer coefficient, showed that the appropriate modifier concentration was able to improve the Pb and Zn enrichment and transfer ability of plants. (2) In subcellular distribution, most of Pb and Zn were distributed in plant cell wall components and soluble components while the distribution in cell organelles such as mitochondria, chloroplasts and nucleus component were less. Compared with CK group, two improved group made soluble components of the cell walls of Pb fixation and retention of zinc role in the enhancement. (3) As for the chemical forms of Pb and Zn in plants, the main chemical forms of Pb were hydrochloric acid, sodium chloride and ethanol extractable forms, while other chemical form contents were few, the main chemical forms of Zn were different based on plant type. Compared with CK group, the proportion of the active Pb chemical form in different plant

  17. Reversible tetramerization of human TK1 to the high catalytic efficient form is induced by pyrophosphate, in addition to tripolyphosphates, or high enzyme concentration

    DEFF Research Database (Denmark)

    Munch-Petersen, Birgitte

    2009-01-01

    of ATP is necessary for tetramerisation and how the reaction velocity is influenced by the enzyme concentration. The results show that only two or three of the phosphate groups of ATP are necessary for tetramerisation, and that kinetics and tetramerisation are closely related. Furthermore, enzyme...... concentration was found to have a pivotal effect on catalytic efficiency.......Thymidine kinase (TK1) is a key enzyme in the salvage pathway of deoxyribonucleotide metabolism catalyzing the first step in the synthesis of dTTP by the transfer of a gamma-phosphate group from a nucleoside triphosphate to the 5´-hydroxyl group of thymidine forming dTMP. Human TK1 is cytosolic...

  18. Nature and reactivity of layered double hydroxides formed by coprecipitating Mg, Al and As(V): Effect of arsenic concentration, pH, and aging.

    Science.gov (United States)

    Sommella, Alessia; Caporale, Antonio G; Denecke, Melissa A; Mangold, Stefan; Pigna, Massimo; Santoro, Anna; Terzano, Roberto; Violante, Antonio

    2015-12-30

    Arsenic (As) co-precipitation is one of the major processes controlling As solubility in soils and waters. When As is co-precipitated with Al and Mg, the possible formation of layered double hydroxides (LDHs) and other nanocomposites can stabilize As in their structures thus making this toxic element less available. We investigated the nature and reactivity of Mg-Al-arsenate [As(V)] co-precipitated LDHs formed in solution affected by As concentration, pH, and aging. At the beginning of the co-precipitation process, poorly crystalline LDH and non-crystalline Al(Mg)-oxides form. Prolonged aging of the samples promotes crystallization of LDHs, evidenced by an increase in As K XANES intensities and XRD peak intensities. During aging Al- and/or Mg-oxides are likely transformed by dissolution/re-precipitation processes into more crystalline but still defective LDHs. Surface area, chemical composition, reactivity of the precipitates, and anion exchange properties of As(V) in the co-precipitates are influenced by pH, aging, and As concentration. This study demonstrates that (i) As(V) retards or inhibits the formation and transformation of LDHs and (ii) more As(V) is removed from solution if co-precipitated with Mg and Al than by sorption onto well crystallized LDHs. PMID:26241870

  19. Shrink tape technique for heat-forming aluminum substrates for thin foil x-ray mirrors and the Neutron Star Interior Composition Explorer x-ray concentrators

    Science.gov (United States)

    Balsamo, Erin; Gendreau, Keith; Okajima, Takashi; Soong, Yang; Serlemitsos, Peter; Jalota, Lalit; Kenyon, Steven; Spartana, Nicholas; Fickau, David; Koenecke, Richard

    2016-01-01

    Consistent improvements in the design and fabrication of thin-foil, epoxy-replicated x-ray mirrors for astronomical telescopes have yielded increasingly higher quality and more precise astrophysical data. The Neutron Star Interior Composition Explorer (NICER) x-ray timing mission optics continues this tradition and introduces design elements that promise even more accurate measurements and precise astrophysical parameters. The singly reflecting concentrators have a curved axial profile to improve photon concentration and a sturdy full shell structure for enhanced module stability. These design elements introduced the challenge of reliably forming mirror substrates at an acceptable production rate. By developing a technique using heat shrink tape to compress and conform thin aluminum mirror substrates to shaping mandrels, production rate improved with successful fabrication. The technique's efficiency was analyzed by measuring hundreds of substrate profiles postforming, performance testing completely assembled concentrators composed of every size substrate, and comparing the results to simulated fabrication scenarios. On average, the profiles were copied within 4.6±3.7%. These measurements and the overall success of NICER's optics, via ground calibration, have shown that the heat-shrink tape method is reliable, repeatable, and could be used in future missions to increase production rate and improve performance.

  20. Effectiveness of 3,4-Dimethylpyrazole Phosphate as Nitrification Inhibitor in Soil as Influenced by Inhibitor Concentration,Application Form,and Soil Matric Potential

    Institute of Scientific and Technical Information of China (English)

    G.BARTH; S.VON TUCHER; U.SCHMIDHALTER

    2008-01-01

    The efficacy of nitrification inhibitors depends on soil properties and environmental conditions.The nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) was investigated in a sandy loam and a loamy soil to study its effectiveness as influenced by inhibitor concentration,application form,and soil matric potential.DMPP was applied with concentrations up to 34.6 mg DMPP kg-1 soil as solution or as ammonium-sulfate/ammonium-nitrate granules formulated with DMPP.DMPP inhibited the oxidation of ammonium in both soils,but this effect was more pronounced in the sandy loam than in the loamy soil When applied as solution,increasing DMPP concentrations up to 7 mg DMPP kg-1 soil had no influence on the inhibition.The effectiveness of DMPP formulated as fertilizer granules was superior to the liquid application of DMPP and NH+,particularly in the loamy soil.Without DMPP,a decline in soil matric potential down to -600 kPa decreased nitrification in both soils,but this effect was more pronounced in the sandy loam than in the loamy soil.DMPP was most effective in the sandy loam particularly under conditions of higher soil moisture,i.e.,under conditions favorable for nitrate leaching.

  1. Influence of elevated CO2 concentrations on cell division and nitrogen fixation rates in the bloom-forming cyanobacterium Nodularia spumigena

    Directory of Open Access Journals (Sweden)

    U. Riebesell

    2009-04-01

    Full Text Available The surface ocean currently absorbs about one-fourth of the CO2 emitted to the atmosphere from human activities. As this CO2 dissolves in seawater, it reacts with seawater to form carbonic acid, increasing ocean acidity and shifting the partitioning of inorganic carbon species towards increased CO2 at the expense of CO32− concentrations. While the decrease in [CO32−] and/or increase in [H+] has been found to adversely affect many calcifying organisms, some photosynthetic organisms appear to benefit from increasing [CO2]. Among these is the cyanobacterium Trichodesmium, a predominant diazotroph (nitrogen-fixing in large parts of the oligotrophic oceans, which responded with increased carbon and nitrogen fixation at elevated pCO2. With the mechanism underlying this CO2 stimulation still unknown, the question arises whether this is a common response of diazotrophic cyanobacteria. In this study we therefore investigate the physiological response of Nodularia spumigena, a heterocystous bloom-forming diazotroph of the Baltic Sea, to CO2-induced changes in seawater carbonate chemistry. N. spumigena reacted to seawater acidification/carbonation with reduced cell division rates and nitrogen fixation rates, accompanied by significant changes in carbon and phosphorus quota and elemental composition of the formed biomass. Possible explanations for the contrasting physiological responses of Nodularia compared to Trichodesmium may be found in the different ecological strategies of non-heterocystous (Trichodesmium and heterocystous (Nodularia cyanobacteria.

  2. WST11, a novel water-soluble bacteriochlorophyll derivative; cellular uptake, pharmacokinetics, biodistribution and vascular-targeted photodynamic activity using melanoma tumors as a model.

    Science.gov (United States)

    Mazor, Ohad; Brandis, Alexander; Plaks, Vicki; Neumark, Eran; Rosenbach-Belkin, Varda; Salomon, Yoram; Scherz, Avigdor

    2005-01-01

    WST11 is a novel negatively charged water-soluble palladium-bacteriochlorophyll derivative that was developed for vascular-targeted photodynamic therapy (VTP) in our laboratory. The in vitro results suggest that WST11 cellular uptake, clearance and phototoxicity are mediated by serum albumin trafficking. In vivo, WST11 was found to clear rapidly from the circulation (t1/2=1.65 min) after intravenous bolus injection in the mouse, whereas a longer clearance time (t1/2=7.5 min) was noted in rats after 20 min of infusion. The biodistribution of WST11 in mouse tissues indicates hepatic clearance (t1/2=20 min), with minor (kidney, lung and spleen) or no intermediary accumulation in other tissues. As soon as 1 h after injection, WST11 had nearly cleared from the body of the mouse, except for a temporal accumulation in the lungs from which it cleared within 40 min. On the basis of these results, we set the VTP protocol for a short illumination period (5 min), delivered immediately after WST11 injection. On subjecting M2R melanoma xenografts to WST11-VTP, we achieved 100% tumor flattening at all doses and a 70% cure with 9 mg/kg and a light exposure dose of 100 mW/cm2. These results provide direct evidence that WST11 is an effective agent for VTP and provide guidelines for further development of new candidates. PMID:15623318

  3. Ultra-broadband 2D electronic spectroscopy of carotenoid-bacteriochlorophyll interactions in the LH1 complex of a purple bacterium.

    Science.gov (United States)

    Maiuri, Margherita; Réhault, Julien; Carey, Anne-Marie; Hacking, Kirsty; Garavelli, Marco; Lüer, Larry; Polli, Dario; Cogdell, Richard J; Cerullo, Giulio

    2015-06-01

    We investigate the excitation energy transfer (EET) pathways in the photosynthetic light harvesting 1 (LH1) complex of purple bacterium Rhodospirillum rubrum with ultra-broadband two-dimensional electronic spectroscopy (2DES). We employ a 2DES apparatus in the partially collinear geometry, using a passive birefringent interferometer to generate the phase-locked pump pulse pair. This scheme easily lends itself to two-color operation, by coupling a sub-10 fs visible pulse with a sub-15-fs near-infrared pulse. This unique pulse combination allows us to simultaneously track with extremely high temporal resolution both the dynamics of the photoexcited carotenoid spirilloxanthin (Spx) in the visible range and the EET between the Spx and the B890 bacterio-chlorophyll (BChl), whose Qx and Qy transitions peak at 585 and 881 nm, respectively, in the near-infrared. Global analysis of the one-color and two-color 2DES maps unravels different relaxation mechanisms in the LH1 complex: (i) the initial events of the internal conversion process within the Spx, (ii) the parallel EET from the first bright state S2 of the Spx towards the Qx state of the B890, and (iii) the internal conversion from Qx to Qy within the B890.

  4. Ultra-broadband 2D electronic spectroscopy of carotenoid-bacteriochlorophyll interactions in the LH1 complex of a purple bacterium

    Energy Technology Data Exchange (ETDEWEB)

    Maiuri, Margherita [CNR-IFN, Dipartimento di Fisica, Politecnico di Milano, P.zza L. da Vinci 32, Milano 20133 (Italy); Department of Chemistry, Princeton University, Washington Road, Princeton, New Jersey 08544 (United States); Réhault, Julien; Polli, Dario; Cerullo, Giulio, E-mail: giulio.cerullo@polimi.it [CNR-IFN, Dipartimento di Fisica, Politecnico di Milano, P.zza L. da Vinci 32, Milano 20133 (Italy); Carey, Anne-Marie; Hacking, Kirsty; Cogdell, Richard J. [Glasgow Biomedical Research Centre, IBLS, University of Glasgow, 126 Place, Glasgow G12 8TA, Scotland (United Kingdom); Garavelli, Marco [Dipartimento di Chimica “G. Ciamician,” Università di Bologna, Via Selmi 2, IT-40126 Bologna (Italy); CNRS, Institut de Chimie de Lyon, École Normale Supérieure de Lyon, Université de Lyon, 46 Allée d’Italie, F-69364 Lyon Cedex 07 (France); Lüer, Larry [Madrid Institute for Advanced Studies, IMDEA Nanociencia, Madrid (Spain)

    2015-06-07

    We investigate the excitation energy transfer (EET) pathways in the photosynthetic light harvesting 1 (LH1) complex of purple bacterium Rhodospirillum rubrum with ultra-broadband two-dimensional electronic spectroscopy (2DES). We employ a 2DES apparatus in the partially collinear geometry, using a passive birefringent interferometer to generate the phase-locked pump pulse pair. This scheme easily lends itself to two-color operation, by coupling a sub-10 fs visible pulse with a sub-15-fs near-infrared pulse. This unique pulse combination allows us to simultaneously track with extremely high temporal resolution both the dynamics of the photoexcited carotenoid spirilloxanthin (Spx) in the visible range and the EET between the Spx and the B890 bacterio-chlorophyll (BChl), whose Q{sub x} and Q{sub y} transitions peak at 585 and 881 nm, respectively, in the near-infrared. Global analysis of the one-color and two-color 2DES maps unravels different relaxation mechanisms in the LH1 complex: (i) the initial events of the internal conversion process within the Spx, (ii) the parallel EET from the first bright state S{sub 2} of the Spx towards the Q{sub x} state of the B890, and (iii) the internal conversion from Q{sub x} to Q{sub y} within the B890.

  5. A new form of land concentration in Colombia Una nueva forma de concentración de la tierra en Colombia:la ley 1448 de 2011

    Directory of Open Access Journals (Sweden)

    Juan Pablo Henao Guzmán

    2012-06-01

    Full Text Available This article aims to show how the Law 1448 of 2011, which explains reparation and restitution of victims, and the National Development Plan (NDP 2011-2014 generate land concentration in Colombia. This is due to how the NDP objectives disintegrate the Law 1448 objectives; this phenomenon could be explained using an agency model and the subsequent moral risk issue formed between the State and the victims. Regarding these results, a game-theory model was built, and this effectively concludes that the Law 1448 and the NDP generate land concentration in ColombiaEn este artículo se pretende mostrar, mediante un análisis económico, cómo la Ley 1448 de 2011 (o Ley de Víctimas y Restitución de Tierras, junto al Plan Nacional de Desarrollo (PND 2011-2014, generan concentración de la tierra en Colombia. Esto se debe a que los objetivos del PND terminan disgregando los que busca la Ley 1448, lo cual se explica con el uso de un modelo de agencia y el subsecuente problema de riesgo moral para el Estado y las víctimas del conflicto. A partir de los resultados anteriores se construye un modelo de teoría de juegos, del que se concluye que, efectivamente, la Ley 1448 y el PND generan concentración de la tierra en Colombia.

  6. Genetic deletion of melanin-concentrating hormone neurons impairs hippocampal short-term synaptic plasticity and hippocampal-dependent forms of short-term memory.

    Science.gov (United States)

    Le Barillier, Léa; Léger, Lucienne; Luppi, Pierre-Hervé; Fort, Patrice; Malleret, Gaël; Salin, Paul-Antoine

    2015-11-01

    The cognitive role of melanin-concentrating hormone (MCH) neurons, a neuronal population located in the mammalian postero-lateral hypothalamus sending projections to all cortical areas, remains poorly understood. Mainly activated during paradoxical sleep (PS), MCH neurons have been implicated in sleep regulation. The genetic deletion of the only known MCH receptor in rodent leads to an impairment of hippocampal dependent forms of memory and to an alteration of hippocampal long-term synaptic plasticity. By using MCH/ataxin3 mice, a genetic model characterized by a selective deletion of MCH neurons in the adult, we investigated the role of MCH neurons in hippocampal synaptic plasticity and hippocampal-dependent forms of memory. MCH/ataxin3 mice exhibited a deficit in the early part of both long-term potentiation and depression in the CA1 area of the hippocampus. Post-tetanic potentiation (PTP) was diminished while synaptic depression induced by repetitive stimulation was enhanced suggesting an alteration of pre-synaptic forms of short-term plasticity in these mice. Behaviorally, MCH/ataxin3 mice spent more time and showed a higher level of hesitation as compared to their controls in performing a short-term memory T-maze task, displayed retardation in acquiring a reference memory task in a Morris water maze, and showed a habituation deficit in an open field task. Deletion of MCH neurons could thus alter spatial short-term memory by impairing short-term plasticity in the hippocampus. Altogether, these findings could provide a cellular mechanism by which PS may facilitate memory encoding. Via MCH neuron activation, PS could prepare the day's learning by increasing and modulating short-term synaptic plasticity in the hippocampus.

  7. Elliptical concentrators.

    Science.gov (United States)

    Garcia-Botella, Angel; Fernandez-Balbuena, Antonio Alvarez; Bernabeu, Eusebio

    2006-10-10

    Nonimaging optics is a field devoted to the design of optical components for applications such as solar concentration or illumination. In this field, many different techniques have been used to produce optical devices, including the use of reflective and refractive components or inverse engineering techniques. However, many of these optical components are based on translational symmetries, rotational symmetries, or free-form surfaces. We study a new family of nonimaging concentrators called elliptical concentrators. This new family of concentrators provides new capabilities and can have different configurations, either homofocal or nonhomofocal. Translational and rotational concentrators can be considered as particular cases of elliptical concentrators. PMID:17068595

  8. Spectral properties of BChl c in nematic liquid crystals. II: Aggregated form of dye

    Science.gov (United States)

    Dudkowiak, A.; Francke, C.; Amesz, J.; Planner, A.; Frackowiak, D.

    1996-11-01

    The orientation properties of aggregated bacteriochlorophyll c in a nematic liquid crystal matrix have been studied by means of polarized steady-state and time-resolved spectroscopy. The pigment introduced to the model system was predominantly in tetrameric (or hexameric) form with absorption maxima located at about 670 and 710 nm. Two tetramers with long-wavelength maxima at 704 and 722 nm could be distinguished. They exhibited different orientations in liquid crystal and different yields of fluorescence. Both tetramers exhibited delayed luminescence in the μs time region.

  9. Pheophytinization of bacteriochlorophyll c and energy transfer in cells of Chlorobium tepidum

    DEFF Research Database (Denmark)

    Tokita, S; Hirota, M; Frigaard, N-U;

    1999-01-01

    medium, normal growth was observed after a short lag phase, and the absorption spectrum of the growing cells showed the presence of a normal amount of BChl c. During the growth of C. tepidum in the new culture, the BChl c concentration was nearly proportional to the cell density measured by turbidity (OD...... spectrum showed maxima at 775 and 810 nm, which correspond to emissions from BChl c and BChl a, respectively. This indicates energy transfer from BPhe c to BChl c and BChl a. In cells in which BChl c was completely pheophytinized, fluorescence measurements were indicative of direct energy transfer from...

  10. Characterization of the microaerophilic, bacteriochlorophyll a-containing bacterium Gemmatimonas phototrophica sp. nov., and emended descriptions of the genus Gemmatimonas and Gemmatimonas aurantiaca.

    Science.gov (United States)

    Zeng, Yonghui; Selyanin, Vadim; Lukeš, Martin; Dean, Jason; Kaftan, David; Feng, Fuying; Koblížek, Michal

    2015-08-01

    A red-pigmented, bacteriochlorophyll (BChl) a-producing strain, AP64T, was isolated previously from the freshwater Swan Lake located in the western Gobi Desert. Based on its 16S rRNA gene sequence identity (96.1%) to the type strain Gemmatimonas aurantiaca T-27T, the new isolate was tentatively classified as a member of the bacterial phylum Gemmatimonadetes. Here, we report its formal description and polyphasic characterization. Strain AP64T grew best on agar media under 9.8-15.2% atmospheric oxygen. The cells were rods, dividing by symmetrical or asymmetrical binary fission. Budding structures were also observed. Its genomic DNA G+C content was 64.4% (from the draft genome sequence). Phylogenetic analysis based on the 16S rRNA gene sequence clearly separated AP64T from related species. Its genotypic differentiation from phylogenetically close relatives was further supported by performing in silico DNA-DNA hybridization and calculating average nucleotide identity, whereas the high percentage (67.3%) of shared conserved proteins between strain AP64T and Gemmatimonas aurantiaca T-27T supports the classification of the two strains into the same genus. Strain AP64T contained C16 : 1, C14 : 1 and C18 : 1ω9c as predominant fatty acids. The main respiratory quinone was menaquinone 8 (MK-8). The most distinctive feature of strain AP64T was the presence of fully functional purple bacterial photosynthetic reaction centres. The main CO2-fixation pathways were absent. Strain AP64T was capable of growth and BChl production in constant darkness. Thus, strain AP64T is a facultatively photoheterotrophic organism. It represents a novel species of the genus Gemmatimonas, for which the name Gemmatimonasphototrophica sp. nov. is proposed. The type strain is AP64T ( = DSM 29774T = MCCC 1K00454T). Emended descriptions of the genus Gemmatimonas and Gemmatimonas aurantiaca are also provided.

  11. Elliptical concentrators

    OpenAIRE

    García Botella, Ángel; Álvarez Fernández Balbuena, Antonio; Bernabeu Martínez, Eusebio

    2006-01-01

    Nonimaging optics is a field devoted to the design of optical components for applications such as solar concentration or illumination. In this field, many different techniques have been used to produce optical devices, including the use of reflective and refractive components or inverse engineering techniques. However, many of these optical components are based on translational symmetries, rotational symmetries, or free-form surfaces. We study a new family of nonimaging concentrators called e...

  12. Biofortification of lettuce (Lactuca sativa L.) with iodine: The effect of iodine form and concentration in the nutrient solution on growth, development and iodine uptake of lettuce grown in water culture

    NARCIS (Netherlands)

    Voogt, W.; Holwerda, H.T.; Khodabaks, M.R.

    2010-01-01

    BACKGROUND: Iodine is an essential trace element for humans. Two billion individuals have insufficient iodine intake. Biofortification of vegetables with iodine offers an excellent opportunity to increase iodine intake by humans. The main aim was to study the effect of iodine form and concentration

  13. Xylem sap collection and extraction methodologies to determine in vivo concentrations of ABA and its bound forms by gas chromatography-mass spectrometry (GC-MS)

    OpenAIRE

    Netting Andrew G; Theobald Julian C; Dodd Ian C

    2012-01-01

    Abstract Background Accurate quantification of xylem sap ABA concentrations is important to underpin models of root-to-shoot ABA signalling to predict the physiological effects of soil drying. Growing tomato plants in a whole plant pressure chamber allowed sequential xylem sap collection from a detached leaf, the petiole stub of an otherwise intact plant and finally the de-topped root system of the same plant, to determine the impact of xylem sap sampling methodology on xylem ABA concentratio...

  14. Activity concentrations of {sup 238}U and {sup 226}Ra in scales formed on pipes of industrial boilers in the state of Pernambuco, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Poggi, Claudia M.B.; Farias, Emerson E.G. de, E-mail: claudiapoggi04@gmail.com, E-mail: emersonemiliano@yahoo.com.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Departamento de Energia Nuclear; Franca, Elvis J.; Hazin, Clovis A., E-mail: chazin@cnen.gov.br [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Gazineu, Maria H.P., E-mail: helena@unicap.br [Universidade Catolica de Pernambuco (UNICAP), Recife, PE (Brazil). Centro de Ciencias e Tecnologia

    2015-07-01

    The procedures employed in the industry can generate significant amounts of solid, liquid and gaseous wastes that usually contain toxic or materials of difficulty degradation. One of the facts that contribute to the formation of such wastes is the generation of steam used in operating processes and industry segments. Currently, steam supplied by boilers is the most economical and practical mode of heat transfer in industrial processes. Due to the high temperature of water used in these processes, compounds which were previously soluble become insoluble, generating residues called scales. This material, which contains stable ions, can also present naturally occurring radionuclides such as {sup 238}U and {sup 226}Ra, which concentrate over time in piping and equipment surfaces. If not disposed correctly, this material also can contaminate the environment. The main origin of these radionuclides is the use of groundwater in industrial processes. Thus, in regions of naturally enriched in radionuclides such as the Region of Pernambuco, including the municipalities of Paulista and Goiana, there is a greater possibility of radioactive scale formation. Therefore, this study aimed to determine the activity concentrations of {sup 238}U and {sup 226}Ra present in the solid wastes generated by industries situated in Paulista and Goiana, in order to assess radionuclide disequilibrium. For the sake of comparison, scale samples collected from industries located in the municipality of Caruaru, far from the previous municipalities, were also analyzed. The determination of the activity concentrations for {sup 238}U and {sup 226}Ra was performed by High Resolution Gamma-Ray Spectrometry. Samples were collected, prepared, packed in plastic containers and set aside for a minimum time of 21 days, for the secular equilibrium to occur between {sup 226}Ra and its short lived descendants. The counting time was 80,000 seconds. Gamma energies used for determination of activity concentrations

  15. Effect of oxygen availability and pH on the furan concentration formed during thermal preservation of plant-based foods.

    Science.gov (United States)

    Palmers, Stijn; Grauwet, Tara; Vanden Avenne, Laura; Verhaeghe, Thomas; Kebede, Biniam T; Hendrickx, Marc E; Van Loey, Ann

    2016-01-01

    Thermally treated fruit- and vegetable-based foods are important contributors to the furan exposure of children and adults. Furan reduction by adding or removing precursors from the product has proven to be challenging because of major food constituents and interactions involved in the reaction pathways leading to furan formation. Instead of intervening at the precursor level, it might be more feasible to influence these formation pathways by adjusting the matrix properties of the product. As opposed to many previous literature sources, the present study investigated the effects of oxygen availability (normal versus reduced) and pH (acid versus low acid) on the furan formation in a real food system. Different combinations of both matrix properties were prepared in a reconstituted potato purée and subjected to a thermal treatment with a pasteurisation or sterilisation intensity. Irrespective of the addition of the furan precursors ascorbic acid, fructose and fatty acids, a considerable furan reduction was observed for the sterilised purées (F121(10) = 15 min) with either a reduced oxygen availability (0.1-1.8 mg l(-1)) or at pH 3. The effects of both matrix properties were less pronounced in the pasteurised purées (P90(10) = 10 min), because of the lower furan concentrations. Even though the mechanisms of furan reduction for both types of matrix properties could not be fully elucidated, the results showed that lowering the oxygen concentration or pH prior to thermal processing offers a powerful, additional strategy for furan mitigation in thermally treated plant-based foods. PMID:26879747

  16. Teaching Form as Form

    DEFF Research Database (Denmark)

    Keiding, Tina Bering

    2012-01-01

    means that form serves both as the connective value and as the concept for reflection. In other words, form is observed as form, not anything else. The didactical challenge of teaching form as form is accentuated by students’ everyday-based pre-orientation towards function at the expense of form...... reveal highly-structured courses, which alternates systematically between steering and free experimental activities. Consistent with a strong focus on content and the student’s interaction with content, the contributions hardly address the role of the teacher or the interplay between teachers...... and students. This is not to say that teachers do not engage in teaching. They clearly do and obviously play a major role in the progression in course structure and reflection on the student’s learning. My point is that, by neglecting the role of the teacher and the interplay between the teacher and students...

  17. Collaborative form(s)

    DEFF Research Database (Denmark)

    Gunn, Wendy

    the process of research rather than its object. In its temporal orientation, anthropology by means of design moves, ‘…forward with people in tandem with their desires and aspirations rather than going back over times passed’ (ibid 2013: 141). Doing design by means of anthropology takes as its most fundamental......Gunn asks us to consider beauty as collaborative forms of action generated by moving between design by means of anthropology and anthropology by means of design. Specifically, she gives focus to play-like reflexions on practices of designing energy products, systems and infrastructure. Design...

  18. 地下水化学组分存在形式及其质量浓度的计算%Existing forms of groundwater chemical components and calculation to its mass concentration

    Institute of Scientific and Technical Information of China (English)

    胡筱; 张永祥; 王一凡; 张晓叶; 兰双双

    2015-01-01

    根据质量守恒定律以及化学热力学平衡常数法,建立了地下水水质组分存在形式及其质量浓度计算的数学模型,并利用MATLAB编写了相应程序,对北京市朝阳区地下水水质检测数据进行实例计算。结果表明:水中化学组分的存在形式包括单一离子、复阴离子、络合离子以及络合分子;游离态的Ca2+、Mg2+、SO2-4占各自离子总质量浓度的百分数分别为85.26%,87.01%,69.85%,表明水样分析质量浓度与计算质量浓度间存在差异;pH值对地下水中游离离子的质量浓度将产生影响,造成离子迁移能力的变化。%Based on the mass conservation law and the method of chemical thermodynamic equilibrium constant , a mathematical model for calculating the existing forms of groundwater chemical components and its mass concentration was established .Based on MATLAB , a corresponding program to calculate the groundwater quality testing data of Chaoyang District , Beijing was written .The results show that the existing forms of groundwater chemical components include single ions , complex anions , complex ions and complex molecules; Dissociative Ca2+, Mg2+, SO42-accounted for mass concentration of Ca 2+, Mg2+, SO42-, respectively, 85.26%,87.01%, 69.85%, which claims the difference between analysis concentration and calculated concentration; The value of pH exerts an influence on the concentration of free ions in groundwater , which causes the changes of ion migration ability.

  19. Trypanocidal activity of genotoxic concentration of benznidazole on epimastigote forms of Trypanosoma cruzi = Atividade tripanocida da concentração genotóxica do benzonidazol em formas epimastigotas de Trypanosoma cruzi

    Directory of Open Access Journals (Sweden)

    Edilson Nobuyoshi Kaneshima

    2012-10-01

    Full Text Available The genotoxicity of benznidazole at a concentration of 75 µM, used in the treatment of Chagas’ disease, has been recently reported. The present study evaluated the inhibitory effect of benznidazole on the growth of epimastigote forms of T. cruzi I and II by using genotoxic (75 µM and non-genotoxic (50 µM concentrations. To assess the growth rates of T. cruzi strains G2, A2.1A, CL, Y, and 2052, parasites in the epimastigote form were cultured in LIT medium for 192 h at 28ºC, with (50 and 75 µM and without (negative control benznidazole. Benznidazole at both concentrations inhibited all the strains, regardless of genetic group. In the 75 µM concentration, there was a significant decrease in the number of parasites inoculated at T0 after 96 h incubation. The results showed that although genotoxic and non-genotoxic doses of benznidazole inhibit the growth of the epimastigote forms of T. cruzi I and II, only the 75 µM dose seem to indicate a possible trypanocidal effect.O benzonidazol é um medicamento utilizado no tratamento da doença de Chagas, cuja genotoxicidade foi recentemente observada em concentrações a partir de 75 µM. O efeito inibitório do benzonidazol sobre o crescimento de formas epimastigotas de T. cruzi I e II foi avaliado no presente trabalho, utilizando-se concentrações genotóxica (75 µM e não genotóxica (50 µM deste medicamento. Para avaliação da taxa de crescimento das cepas G2, A2.1A, CL, Y e 2052, os parasitos na forma epimastigota foram cultivados em meio LIT, durante 192 horas, à 28 o C, tanto em presença de benzonidazol (50 e 75 µM, quanto em sua ausência (controle negativo. O efeito inibitório do benzonidazol, em ambas concentrações, foi observado para todas as cepas analisadas, independentemente do grupo genético a que pertençam. Na concentração de 75 µM, observou-se após 96 horas de incubação, redução significativa do número de parasitos inoculados no tempo zero (T0. Os resultados

  20. Concentrated Ownership

    DEFF Research Database (Denmark)

    Rose, Caspar

    2014-01-01

    , especially minority shareholders. Concentrated ownership is associated with benefits and costs. Concentrated ownership may reduce agency costs by increased monitoring of top management. However, concentrated ownership may also provide dominating owners with private benefits of control....

  1. Concentration device

    DEFF Research Database (Denmark)

    2013-01-01

    A concentration device (2) for filter filtration concentration of particles (4) from a volume of a fluid (6). The concentration device (2) comprises a filter (8) configured to filter particles (4) of a predefined size in the volume of the fluid (6). The concentration device (2) comprises...

  2. Variáveis ruminais, concentração de uréia plasmática e excreções urinárias de nitrogênio em vacas leiteiras alimentadas com concentrado processado de diferentes formas Ruminal metabolism, plasma urea concentration, and urinary excretion of nitrogen of dairy cows fed concentrate processed in different forms

    Directory of Open Access Journals (Sweden)

    Humberto Luiz Wernersbach Filho

    2006-06-01

    Full Text Available O objetivo neste estudo foi avaliar a influência do tipo de processamento do concentrado sobre o pH e a amônia ruminal, a concentração de uréia no plasma e as excreções urinárias de vacas leiteiras alimentadas com dietas contendo diferentes relações volumoso:concentrado. Foram utilizadas 16 vacas da raça Holandesa, puras e mestiças, em dois níveis de produção de leite (30 e 20 kg/dia, distribuídas em quatro quadrados latinos (dois para cada nível de produção, com quatro períodos de 15 dias. As dietas experimentais, isoprotéicas, foram constituídas à base de silagem de milho com relações volumoso:concentrado 50:50 e 60:40 na MS, visando produções de 30 e 20 kg de leite/dia, respectivamente. Imediatamente antes e 3 horas após a alimentação matinal, não houve diferenças nos valores de pH e amônia ruminal nos diferentes níveis de produção. Contudo, nas vacas alimentadas com a dieta com concentrado extrusado, a concentração de amônia ruminal foi menor 3 horas após a alimentação. Não houve diferença nas concentrações de uréia plasmática entre os tratamentos e as excreções urinárias de nitrogênio diferiram somente com o concentrado contendo alto teor de energia parcialmente processado.The objective of this trial was to study the effects of different forms of concentrate processing on ruminal pH and ammonia as well as on plasma concentration of urea. Sixteen dairy cows, pure Holstein and crossbred, were blocked by production level (30.0 and 20.0 kg/day and randomly assigned to two Latin squares with four periods of 15 days each. Diets were isonitrogenous and contained the following forage (corn silage:concentrate ratios: 50:50 and 60:40 (% of DM for cows yielding 30.0 and 20.0 kg of milk/day, respectively. Ruminal pH and ammonia (N-NH3 did not differ at 0 h (pre-feeding and at 3 h after the morning feeding in the different production levels. However, it was observed lower ruminal ammonia concentration

  3. Concentrator Photovoltaics

    CERN Document Server

    Luque, Antonio L

    2007-01-01

    Photovoltaic solar-energy conversion is one of the most promising technologies for generating renewable energy, and conversion of concentrated sunlight can lead to reduced cost for solar electricity. In fact, photovoltaic conversion of concentrated sunlight insures an efficient and cost-effective sustainable power resource. This book gives an overview of all components, e.g. cells, concentrators, modules and systems, for systems of concentrator photovoltaics. The authors report on significant results related to design, technology, and applications, and also cover the fundamental physics and market considerations. Specific contributions include: theory and practice of sunlight concentrators; an overview of concentrator PV activities; a description of concentrator solar cells; design and technology of modules and systems; manufacturing aspects; and a market study.

  4. 利用迈克尔逊干涉仪形成等间距同心圆状等厚干涉条纹%Concentric-ring Fringes with Equal Fringe Spacing Formed by Equal Thickness Interference in Michelson Interferometer

    Institute of Scientific and Technical Information of China (English)

    毛志国

    2015-01-01

    为了在教学过程加深对迈克尔逊干涉仪的理解,用锥顶角很大的圆锥形凸面镜或凹面镜替换平面反射镜,形成了明暗相间、等间距、同心圆状的等厚干涉条纹。针对两个镜子的不同组合,计算了该等厚干涉的条纹半径、条纹间距,并分析了条纹级次及条纹变动等特点。结果表明:对于条纹级次内高外低的等厚干涉图样,当膜变厚时,中心亮环往外冒;反之,膜变薄时,中心亮环往里吞,这与等倾干涉的条纹变动相似。而对于条纹级次内低外高的等厚干涉图样,当膜变厚时,中心亮环往里吞;反之,膜变薄时,中心亮环往外冒,这与等倾干涉的条纹变动相反。%In the interest of the thorough understanding of Michelson interferometer in teaching process, the alternately dark and bright concentric-ring fringes with an equal fringe spacing are formed by equal thickness interference in Michelson interferometer through the convex conic mirror or concave conic mirror with larger vertex angle taking place of the plane mirror. The radius, the fringe spacing, the order, and the change of fringe are analyzed in different cases. For the in-terference pattern with the higher order at the center, the bright-ring fringe emits from the center with the increase of air film thickness, while the bright-ring fringe shrinks inward with the decreasing of film thickness. This is similar to the change of fringes by equal inclination interference. For the interference pattern with the lower order at the center, the bright-ring fringe shrinks inward with the increase of air film thickness, while the bright-ring fringe emits from the center with the decreasing of film thickness. This is different from the change of fringes by equal inclination interference.

  5. Concentrating Radioactivity

    Science.gov (United States)

    Herrmann, Richard A.

    1974-01-01

    By concentrating radioactivity contained on luminous dials, a teacher can make a high reading source for classroom experiments on radiation. The preparation of the source and its uses are described. (DT)

  6. Konsentrasi Protein Total, Albumin, dan Globulin Anak Kambing Peranakan Etawah Setelah Pemberian Berbagai Sediaan Kolostrum* (TOTAL PROTEIN, ALBUMIN, AND GLOBULIN CONCENTRATIONS ON ETTAWAH CROSSBREED NEONATES FOLLOWING THE ADMINISTRATION OF VARIOUS FORM O

    Directory of Open Access Journals (Sweden)

    Anita Esfandiari

    2014-10-01

    Full Text Available This experiment was conducted to study the profile of total protein, albumin, and globulin concentrationson Ettawah crossbreed neonates after consuming various colostrums. Twenty four healthy neonatal kidswere used in this study. The neonates were divided into four groups. Each group received fresh maternal(goat colostrum, frozen-thawed bovine colostrum, bovine spray dried colostrum, and bovine powdercommercial colostrum, respectively. Colostrums were given at 10% of body weight directly after birth andfollowed by the same amount every 12 hours, for three days. The blood was taken from jugular vein at 0, 12,24, 48, 72, and 168 hours after birth to determine total protein, albumin, and globulin concentrations.Results of this study indicated that the serum total protein and globulin concentration increased andreached the peak at 24 hours after birth. Compared to the concentration at birth, the increase of totalprotein concentration were 62.77%, 59.26%, 48.05%, and 66.67% in fresh maternal (goat, frozen-thawedbovine, bovine spray dried, and commercial bovine colostrum, respectively. Serum globulin concentrationincreased 4.9, 4.4, 4.8, and 14.6 times in fresh matermnal goat, frozen-thawed bovine, spray dried, andcommercial bovine colostrums respectively, compared to the concentration at birth. In conclusion, theconsumption of various colostrums i.e. fresh maternal goat colostrums, bovine colostrums (frozen-thawed,spray dried and commercial colostrums would increase the concentration of blood total protein and globulin,which both reached the highest concentration at 24 h after birth.

  7. Cosmic Forms

    CERN Document Server

    Kleman, Maurice

    2011-01-01

    The continuous 1D defects of an isotropic homogeneous material in an Euclidean 3D space are classified by a construction method, the Volterra process (VP). We employ the same method to classify the continuous 2D defects (which we call \\textit{cosmic forms}) of a vacuum in a 4D maximally symmetric spacetime. These defects fall into three different classes: i)- $m$-forms, akin to 3D space disclinations, related to ordinary rotations and analogous to Kibble's global cosmic strings (except that being continuous any deficit angle is allowed); ii)- $t$-forms, related to Lorentz boosts (hyperbolic rotations); iii)- $r$-forms, never been considered so far, related to null rotations. A detailed account of their metrics is presented. Their inner structure in many cases appears as a non-singular \\textit{core} separated from the outer part by a timelike hypersurface with distributional curvature and/or torsion, yielding new types of geometrical interactions with cosmic dislocations and other cosmic disclinations. Whereas...

  8. Visualization of Steady-State Ionic Concentration Profiles Formed in Electrolytes during Li-Ion Battery Operation and Determination of Mass-Transport Properties by in Situ Magnetic Resonance Imaging.

    Science.gov (United States)

    Krachkovskiy, Sergey A; Bazak, J David; Werhun, Peter; Balcom, Bruce J; Halalay, Ion C; Goward, Gillian R

    2016-06-29

    Accurate modeling of Li-ion batteries performance, particularly during the transient conditions experienced in automotive applications, requires knowledge of electrolyte transport properties (ionic conductivity κ, salt diffusivity D, and lithium ion transference number t(+)) over a wide range of salt concentrations and temperatures. While specific conductivity data can be easily obtained with modern computerized instrumentation, this is not the case for D and t(+). A combination of NMR and MRI techniques was used to solve the problem. The main advantage of such an approach over classical electrochemical methods is its ability to provide spatially resolved details regarding the chemical and dynamic features of charged species in solution, hence the ability to present a more accurate characterization of processes in an electrolyte under operational conditions. We demonstrate herein data on ion transport properties (D and t(+)) of concentrated LiPF6 solutions in a binary ethylene carbonate (EC)-dimethyl carbonate (DMC) 1:1 v/v solvent mixture, obtained by the proposed technique. The buildup of steady-state (time-invariant) ion concentration profiles during galvanostatic experiments with graphite-lithium metal cells containing the electrolyte was monitored by pure phase-encoding single point imaging MRI. We then derived the salt diffusivity and Li(+) transference number over the salt concentration range 0.78-1.27 M from a pseudo-3D combined PFG-NMR and MRI technique. The results obtained with our novel methodology agree with those obtained by electrochemical methods, but in contrast to them, the concentration dependences of salt diffusivity and Li(+) transference number were obtained simultaneously within the single in situ experiment. PMID:27250238

  9. Regeneration to OH{sup -} form of anionic Dowex 1-X8 and Dowex 2-X8 resins as a function of concentration of eluent solution; Regeneracao de resinas anionicas Dowex 1-X8 e Dowex 2-X8 a forma OH{sup -} em funcao da concentracao da solucao eluente

    Energy Technology Data Exchange (ETDEWEB)

    Bendassolli, Jose Albertino; Trivelin, Paulo Cesar Ocheuse [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil)]. E-mails: jbendass@cena.usp.br; pcotrive@pira.cena.usp.br; Carneiro Junior, Francisco [Universidade Metodista de Piracicaba (UNIMEP), SP (Brazil). Dept. de Fisica]. E-mail: fcarneir@unimep.br

    1998-06-01

    The main objective of the present paper was to evaluate the regeneration process of Dowex 1-X8 and Dowex 2-X8, 100-200 mesh anionic resins, from Cl{sup -} to OH{sup -} forms. The efficiency of the regeneration process with different concentrations of the eluent sodium hydroxide solution was determined. (author)

  10. Automorphic Forms

    DEFF Research Database (Denmark)

    von Essen, Flemming Brændgaard

    -functions for Hecke characters in the points 4 and 6. It is well known, that all zeros of the Eisenstein series Ek wrt. SL2(Z) in the standard fundamental domain has modulus 1. We show that this is also true for #n Ek, where # is a certain differential operator. We then proceed to study logarithms of multiplier...... systems. For automorphic forms wrt. Hecke triangle groups and Fuchsian groups with no elliptic elements and genus 0, we show that some logarithms of multiplier systems can be interpreted as a linking number. Finally we show a "twisted" version of the prime geodesics theorem, and logarithms of multiplier...

  11. Comparison of secondary organic aerosol formed with an aerosol flow reactor and environmental reaction chambers: effect of oxidant concentration, exposure time and seed particles on chemical composition and yield

    Directory of Open Access Journals (Sweden)

    A. T. Lambe

    2014-12-01

    Full Text Available We performed a systematic intercomparison study of the chemistry and yields of SOA generated from OH oxidation of a common set of gas-phase precursors in a Potential Aerosol Mass (PAM continuous flow reactor and several environmental chambers. In the flow reactor, SOA precursors were oxidized using OH concentrations ranging from 2.0×108 to 2.2×1010 molec cm−3 over exposure times of 100 s. In the environmental chambers, precursors were oxidized using OH concentrations ranging from 2×106 to 2×107 molec cm−3 over exposure times of several hours. The OH concentration in the chamber experiments is close to that found in the atmosphere, but the integrated OH exposure in the flow reactor can simulate atmospheric exposure times of multiple days compared to chamber exposure times of only a day or so. A linear correlation analysis of the mass spectra (m=0.91–0.92, r2=0.93–0.94 and carbon oxidation state (m=1.1, r2=0.58 of SOA produced in the flow reactor and environmental chambers for OH exposures of approximately 1011 molec cm−3 s suggests that the composition of SOA produced in the flow reactor and chambers is the same within experimental accuracy as measured with an aerosol mass spectrometer. This similarity in turn suggests that both in the flow reactor and in chambers, SOA chemical composition at low OH exposure is governed primarily by gas-phase OH oxidation of the precursors, rather than heterogeneous oxidation of the condensed particles. In general, SOA yields measured in the flow reactor are lower than measured in chambers for the range of equivalent OH exposures that can be measured in both the flow reactor and chambers. The influence of sulfate seed particles on isoprene SOA yield measurements was examined in the flow reactor. The studies show that seed particles increase the yield of SOA produced in flow reactors by a factor of 3 to 5 and may also account in part for higher SOA yields obtained in the chambers, where seed

  12. Sixth form pure mathematics

    CERN Document Server

    Plumpton, C

    1968-01-01

    Sixth Form Pure Mathematics, Volume 1, Second Edition, is the first of a series of volumes on Pure Mathematics and Theoretical Mechanics for Sixth Form students whose aim is entrance into British and Commonwealth Universities or Technical Colleges. A knowledge of Pure Mathematics up to G.C.E. O-level is assumed and the subject is developed by a concentric treatment in which each new topic is used to illustrate ideas already treated. The major topics of Algebra, Calculus, Coordinate Geometry, and Trigonometry are developed together. This volume covers most of the Pure Mathematics required for t

  13. Densified waste form and method for forming

    Energy Technology Data Exchange (ETDEWEB)

    Garino, Terry J.; Nenoff, Tina M.; Sava Gallis, Dorina Florentina

    2015-08-25

    Materials and methods of making densified waste forms for temperature sensitive waste material, such as nuclear waste, formed with low temperature processing using metallic powder that forms the matrix that encapsulates the temperature sensitive waste material. The densified waste form includes a temperature sensitive waste material in a physically densified matrix, the matrix is a compacted metallic powder. The method for forming the densified waste form includes mixing a metallic powder and a temperature sensitive waste material to form a waste form precursor. The waste form precursor is compacted with sufficient pressure to densify the waste precursor and encapsulate the temperature sensitive waste material in a physically densified matrix.

  14. Densified waste form and method for forming

    Energy Technology Data Exchange (ETDEWEB)

    Garino, Terry J.; Nenoff, Tina M.; Sava Gallis, Dorina Florentina

    2016-05-17

    Materials and methods of making densified waste forms for temperature sensitive waste material, such as nuclear waste, formed with low temperature processing using metallic powder that forms the matrix that encapsulates the temperature sensitive waste material. The densified waste form includes a temperature sensitive waste material in a physically densified matrix, the matrix is a compacted metallic powder. The method for forming the densified waste form includes mixing a metallic powder and a temperature sensitive waste material to form a waste form precursor. The waste form precursor is compacted with sufficient pressure to densify the waste precursor and encapsulate the temperature sensitive waste material in a physically densified matrix.

  15. Scattering Solar Thermal Concentrators

    Energy Technology Data Exchange (ETDEWEB)

    Giebink, Noel C. [Pennsylvania State Univ., State College, PA (United States)

    2015-01-31

    concentrator optical efficiency was found to decrease significantly with increasing aperture width beyond 0.5 m due to parasitic waveguide out-coupling loss and low-level absorption that become dominant at larger scale. A heat transfer model was subsequently implemented to predict collector fluid heat gain and outlet temperature as a function of flow rate using the optical model as a flux input. It was found that the aperture width size limitation imposed by the optical efficiency characteristics of the waveguide limits the absolute optical power delivered to the heat transfer element per unit length. As compared to state-of-the-art parabolic trough CPV system aperture widths approaching 5 m, this limitation leads to an approximate factor of order of magnitude increase in heat transfer tube length to achieve the same heat transfer fluid outlet temperature. The conclusion of this work is that scattering solar thermal concentration cannot be implemented at the scale and efficiency required to compete with the performance of current parabolic trough CSP systems. Applied within the alternate context of CPV, however, the results of this work have likely opened up a transformative new path that enables quasi-static, high efficiency CPV to be implemented on rooftops in the form factor of traditional fixed-panel photovoltaics.

  16. On good ETOL forms

    DEFF Research Database (Denmark)

    Skyum, Sven

    1978-01-01

    This paper continues the study of ETOL forms and good EOL forms done by Maurer, Salomaa and Wood. It is proven that binary very complete ETOL forms exist, good synchronized ETOL forms exist and that no propagating or synchronized ETOL form can be very complete....

  17. Modular Forms and Weierstrass Mock Modular Forms

    Directory of Open Access Journals (Sweden)

    Amanda Clemm

    2016-02-01

    Full Text Available Alfes, Griffin, Ono, and Rolen have shown that the harmonic Maass forms arising from Weierstrass ζ-functions associated to modular elliptic curves “encode” the vanishing and nonvanishing for central values and derivatives of twisted Hasse-Weil L-functions for elliptic curves. Previously, Martin and Ono proved that there are exactly five weight 2 newforms with complex multiplication that are eta-quotients. In this paper, we construct a canonical harmonic Maass form for these five curves with complex multiplication. The holomorphic part of this harmonic Maass form arises from the Weierstrass ζ-function and is referred to as the Weierstrass mock modular form. We prove that the Weierstrass mock modular form for these five curves is itself an eta-quotient or a twist of one. Using this construction, we also obtain p-adic formulas for the corresponding weight 2 newform using Atkin’s U-operator.

  18. Electroweak form factors

    International Nuclear Information System (INIS)

    The present status of electroweak nucleon form factors and the N - Δ transition form factors is reviewed. Particularly the determination of dipole mass MA in the axial vector form factor is discussed

  19. Concentric ring flywheel without expansion separators

    Science.gov (United States)

    Kuklo, Thomas C.

    1999-01-01

    A concentric ring flywheel wherein the adjacent rings are configured to eliminate the need for differential expansion separators between the adjacent rings. This is accomplished by forming a circumferential step on an outer surface of an inner concentric ring and forming a matching circumferential step on the inner surface of an adjacent outer concentric ring. During operation the circumferential steps allow the rings to differentially expand due to the difference in the radius of the rings without the formation of gaps therebetween, thereby eliminating the need for expansion separators to take up the gaps formed by differential expansion.

  20. Photovoltaic concentrator module technology

    Science.gov (United States)

    Richards, Elizabeth H.; Chamberlin, Jay L.; Boes, Eldon C.

    Significant developments in the development of photovoltaic (PV) concentrator technology are described. Concentrator cell research, advances in PV concentrator cell technology, and PV concentrator module development are described. Reliability issues currently of concern, including the applicability of wet insulation resistance tests to concentrator modules, correlation of accelerated thermal cycling tests with life expectancy in the field, and the importance of quality assurance during manufacture, are discussed. Two PV concentrator power systems installed in 1989 are discussed. A PV concentrator initiative program established by the DOE is given, and the results of the latest cost study are presented.

  1. RESTAURANT CONCENTRATION IN LOUISIANA

    OpenAIRE

    Schupp, Alvin R.; Dennis, Winston

    1990-01-01

    Growth of the franchise restaurant industry and merger activity among restaurants raise questions concerning concentration in the Louisiana restaurant industry. Firm employment data from the Louisiana Department of Labor for selected urban and rural parishes for 1975-86 and the concentration ratio, herfindahl index and the entropy measure were used for these concentration estimates. Concentration was, in general, low in urban parishes and higher in rural parishes. Concentration decreased from...

  2. ELECTROCHEMICAL BEHAVIOR OF PASSIVE FILMS FORMED ON X80 PIPELINE STEEL IN VARIOUS CONCENTRATED NaHCO3 SOLUTIONS%X80管线钢钝化膜在各种高浓度NaHCO3溶液中的电化学行为

    Institute of Scientific and Technical Information of China (English)

    范林; 李晓刚; 杜翠薇; 刘智勇

    2012-01-01

    The electrochemical behavior of the passive films formed on X80 pipeline steel in various concen- trated NaHCO3 solutions was studied using potentiodynamic polarization curves, potentiostatic polarization curves, electrochemical impedance spectroscopy (EIS) as well as Mott-Schottky plots. The electrochemical test results indicated n-type semiconducting characters of the passive film, which was composed of two layers, with γ-Fe2O3 as the outer layer, and Fe3O4 as the inner layer. The properties of the passive films were influenced by the concentration of NaHCO3 solutions. The thickness of the inner layer merely remained constant, which was supposed to be dominated by the film forming polarization, whereas the thickness of the outer layer decreased with the increase of the concentration of NaHCO3 solution, which suggested that the outer layer plays a more important role to the corrosion resistance and stability of the passive film. According to the point defect model (PDM), higher donor density and lower thickness of the passive films was affected by the enhanced conductivity of the solution and the intensified adsorption of HCO: at local defect sites with higher HCO3^- concentration.%采用动电位极化曲线、恒电位极化曲线、电化学阻抗谱(EIS)、Mott—Schottky分析等电化学方法研究了X80管线钢在各种高浓度的NaHCO3溶液中形成钝化膜的电化学行为。结果表明,X80管线钢钝化膜的稳定性和耐蚀性会受到NaHCO3溶液浓度的影响。钝化膜电化学性质随HCO3^-浓度升高而降低;内层Fe3O4的厚度不随HCO3^-浓度变化,推测其形成与成膜电位有关;内外膜层厚度比随HCO3^-浓度的升高而增大,钝化膜的稳定性和耐蚀性主要受外层γ-Fe2O3的影响。根据点缺陷(PDM)理论的分析认为,NaHCO3溶液浓度升高时钝化膜稳定性和耐蚀性的降低与溶液电导率的升高和HCO3^-在缺陷点处吸附作用的增强有关。

  3. Bacteria form tellurium nanocrystals

    Science.gov (United States)

    Oremland, R.S.

    2007-01-01

    A team of researchers have found two bacterial species that produce tellurium oxyanions as respiratory electron acceptors for growth, leaving elemental tellurium in the form of nanoparticles. The crystals from the two organisms exhibit distinctively different structures. Bacillus selenitireducens initially forms nanorods that cluster together to form rosettes. Sulfurospirillum barnesii forms irregularly-shaped nanospheres that coalesce into larger composite aggregates.

  4. Generalized Maass Wave Forms

    OpenAIRE

    Mühlenbruch, Tobias; Raji, Wissam

    2012-01-01

    We initiate the study of generalized Maass wave forms, those Maass wave forms for which the multiplier system is not necessarily unitary. We then prove some basic theorems inherited from the classical theory of modular forms with a generalization of some examples from the classical theory of Maass forms.

  5. Adaptive municipal electronic forms

    NARCIS (Netherlands)

    Kuiper, Pieter; Dijk, van Betsy; Bondarouk, Tanya; Ruël, Huub; Guiderdoni-Jourdain, Karine; Oiry, Ewan

    2009-01-01

    Adaptation of electronic forms (e-forms) seems to be a step forward to reduce the burden for people who fill in forms. Municipalities more and more offer e-forms online that can be used by citizens to request a municipal product or service or by municipal employees to place a request on behalf of a

  6. Manufacturing processes 4 forming

    CERN Document Server

    Klocke, Fritz

    2013-01-01

    This book provides essential information on metal forming, utilizing a practical distinction between bulk and sheet metal forming. In the field of bulk forming, it examines processes of cold, warm and hot bulk forming, as well as rolling and a new addition, the process of thixoforming. As for the field of sheet metal working, on the one hand it deals with sheet metal forming processes (deep drawing, flange forming, stretch drawing, metal spinning and bending). In terms of special processes, the chapters on internal high-pressure forming and high rate forming have been revised and refined. On the other, the book elucidates and presents the state of the art in sheet metal separation processes (shearing and fineblanking). Furthermore, joining by forming has been added to the new edition as a new chapter describing mechanical methods for joining sheet metals. The new chapter “Basic Principles” addresses both sheet metal and bulk forming, in addition to metal physics, plastomechanics and computational basics; ...

  7. Arsenic concentrations in Chinese coals

    International Nuclear Information System (INIS)

    The arsenic concentrations in 297 coal samples were collected from the main coal-mines of 26 provinces in China were determined by molybdenum blue coloration method. These samples were collected from coals that vary widely in coal rank and coal-forming periods from the five main coal-bearing regions in China. Arsenic content in Chinese coals range between 0.24 to 71 mg/kg. The mean of the concentration of Arsenic is 6.4 ± 0.5 mg/kg and the geometric mean is 4.0 ± 8.5 mg/kg. The level of arsenic in China is higher in northeastern and southern provinces, but lower in northwestern provinces. The relationship between arsenic content and coal-forming period, coal rank is studied. It was observed that the arsenic contents decreases with coal rank in the order: Tertiary > Early Jurassic > Late Triassic > Late Jurassic > Middle Jurassic > Late Permian > Early Carboniferous > Middle Carboniferous > Late Carboniferous > Early Permian; It was also noted that the arsenic contents decrease in the order: Subbituminous > Anthracite > Bituminous. However, compared with the geological characteristics of coal forming region, coal rank and coal-forming period have little effect on the concentration of arsenic in Chinese coal. The average arsenic concentration of Chinese coal is lower than that of the whole world. The health problems in China derived from in coal (arsenism) are due largely to poor local life-style practices in cooking and home heating with coal rather than to high arsenic contents in the coal

  8. Maass Forms and Quantum Modular Forms

    Science.gov (United States)

    Rolen, Larry

    This thesis describes several new results in the theory of harmonic Maass forms and related objects. Maass forms have recently led to a flood of applications throughout number theory and combinatorics in recent years, especially following their development by the work of Bruinier and Funke the modern understanding Ramanujan's mock theta functions due to Zwegers. The first of three main theorems discussed in this thesis concerns the integrality properties of singular moduli. These are well-known to be algebraic integers, and they play a beautiful role in complex multiplication and explicit class field theory for imaginary quadratic fields. One can also study "singular moduli" for special non-holomorphic functions, which are algebraic but are not necessarily algebraic integers. Here we will explain the phenomenon of integrality properties and provide a sharp bound on denominators of symmetric functions in singular moduli. The second main theme of the thesis concerns Zagier's recent definition of a quantum modular form. Since their definition in 2010 by Zagier, quantum modular forms have been connected to numerous different topics such as strongly unimodal sequences, ranks, cranks, and asymptotics for mock theta functions. Motivated by Zagier's example of the quantum modularity of Kontsevich's "strange" function F(q), we revisit work of Andrews, Jimenez-Urroz, and Ono to construct a natural vector-valued quantum modular form whose components. The final chapter of this thesis is devoted to a study of asymptotics of mock theta functions near roots of unity. In his famous deathbed letter, Ramanujan introduced the notion of a mock theta function, and he offered some alleged examples. The theory of mock theta functions has been brought to fruition using the framework of harmonic Maass forms, thanks to Zwegers. Despite this understanding, little attention has been given to Ramanujan's original definition. Here we prove that Ramanujan's examples do indeed satisfy his

  9. When is Concentration Beneficial?

    OpenAIRE

    Liron-Espana, Carmen; Lopez, Rigoberto A.

    2001-01-01

    This paper separates market power and efficiency effects of concentration in a sample of 255 U.S. manufacturing industries and computes welfare changes from rises in concentration. The empirical findings reveal that in nearly two-third of the cases, consumers lose as efficiency gains are generally pocketed by the industries. From an aggregate welfare standpoint, concentration is found to be beneficial in nearly 70% of the cases, mostly for low and moderate levels of concentration being partic...

  10. Forms of Arthritis

    Science.gov (United States)

    ... this page please turn Javascript on. Forms of Arthritis Past Issues / Fall 2006 Table of Contents Today, ... of Linda Saisselin Osteoarthritis (OA) — the form of arthritis typically occurring during middle or old age, this ...

  11. Solar cell concentrating system

    International Nuclear Information System (INIS)

    This study reviews fabrication techniques and testing facilities for different solar cells under concentration which have been developed and tested. It is also aimed to examine solar energy concentrators which are prospective candidates for photovoltaic concentrator systems. This may provide an impetus to the scientists working in the area of solar cell technology

  12. FORMS OF YOUTH TRAVEL

    OpenAIRE

    Moisã Claudia Olimpia

    2011-01-01

    Taking into account the suite of motivation that youth has when practicing tourism, it can be said that the youth travel takes highly diverse forms. These forms are educational tourism, volunteer programs and “work and travel”, cultural exchanges or sports tourism and adventure travel. In this article, we identified and analyzed in detail the main forms of youth travel both internationally and in Romania. We also illustrated for each form of tourism the specific tourism products targeting you...

  13. Optimal concentration for sugar transport in plants

    OpenAIRE

    Jensen, Kaare H.; Savage, Jessica A.; HOLBROOK, N. MICHELE

    2013-01-01

    Vascular plants transport energy in the form of sugars from the leaves where they are produced to sites of active growth. The mass flow of sugars through the phloem vascular system is determined by the sap flow rate and the sugar concentration. If the concentration is low, little energy is transferred from source to sink. If it is too high, sap viscosity impedes flow. An interesting question is therefore at which concentration is the sugar flow optimal. Optimization of sugar flow and transpor...

  14. A statistical proxy for sulphuric acid concentration

    OpenAIRE

    S. Mikkonen; S. Romakkaniemi; J. N. Smith; Korhonen, H.; Petäjä, T.; Plass-Duelmer, C.; M. Boy; P. H. McMurry; Lehtinen, K. E. J.; Joutsensaari, J.; Hamed, A.(Texas A&M University, College Station, TX, 77843, USA); R. L. Mauldin III; Birmili, W.; Spindler, G; Arnold, F.

    2011-01-01

    Gaseous sulphuric acid is a key precursor for new particle formation in the atmosphere. Previous experimental studies have confirmed a strong correlation between the number concentrations of freshly formed particles and the ambient concentrations of sulphuric acid. This study evaluates a body of experimental gas phase sulphuric acid concentrations, as measured by Chemical Ionization Mass Spectrometry (CIMS) during six intensive measurement campaigns and one long-term observational period. The...

  15. Method for forming ammonia

    Science.gov (United States)

    Kong, Peter C.; Pink, Robert J.; Zuck, Larry D.

    2008-08-19

    A method for forming ammonia is disclosed and which includes the steps of forming a plasma; providing a source of metal particles, and supplying the metal particles to the plasma to form metal nitride particles; and providing a substance, and reacting the metal nitride particles with the substance to produce ammonia, and an oxide byproduct.

  16. Effect of Water-logging Stress and Nitrogen Forms on Amount and Solutes Concentration of Bleeding Sap in Maize Plants at Seeding Stage%淹涝和氮形态对苗期玉米伤流液流量及组分的影响

    Institute of Scientific and Technical Information of China (English)

    刘盼盼; 伍大利; 刘畅; 周毅; 汪建飞

    2013-01-01

      Effect of water conditions(water-logging stress and non-water-logging stress)and nitrogen forms(am-monium,nitrate and the mixture of nitrate and ammonium )on concentration and transport of components in bleeding in the amount of free amino acid in bleeding sap at night and the increase in root activity of nitrate -fed plants disap-peared at the same time.Therefore,it revealed that nitrogen form is a major factor affecting maize plants to adapt to water-logging stress,with the periodic difference existed in the responses of different nitrogen form -fed maize plants to the stress condition.%  采用砂培培养方法,比较研究淹涝与否和不同氮形态(铵态氮、硝态氮以及铵硝态氮以1∶1混合)对苗期玉米伤流液流量及组分的影响。结果表明,与非淹涝胁迫条件相比,在淹涝胁迫处理的第3天,铵态氮处理玉米的根、茎鞘和整株的生物量干物质量显著增加,当胁迫延长至7 d 时,其叶的生物量干质量的增加幅度也达差异显著性水平。此时,其根、茎鞘和叶的生物量干物质量明显高于硝态氮处理,且其中茎鞘的生物量干物质量也明显高于铵、硝混合处理。尽管在遭受淹涝胁迫3 d 时,铵态氮处理的伤流液流量及其中的可溶性糖的量均明显降低,但当胁迫时间延长至7 d 时,其根系活力明显增高,伤流液的流量及其中的可溶性糖的量也均恢复至非淹涝胁迫条件下的水平。相对而言,与非淹涝胁迫条件相比,为期3 d 的淹涝胁迫显著提高硝态氮处理的玉米植株的根系活力,但降低其伤流液流量及其中的硝态氮的量;且随着胁迫时间的延长,其伤流液中的可溶性糖的量也由遭受淹涝胁迫3 d 时的无明显变化的趋势,发展为呈明显的降低趋势;而其夜间伤流液中的氨基酸的量则由明显降低转变为与对照无明显差异;其根系活力也恢复至与对照无显著

  17. Characterization of polymorphic ampicillin forms.

    Science.gov (United States)

    Baraldi, C; Tinti, A; Ottani, S; Gamberini, M C

    2014-11-01

    In this work polymorphs of α-aminobenzylpenicillin (ampicillin), a β-lactamic antibiotic, were prepared and investigated by several experimental and theoretical methods. Amorphous monohydrate and three crystalline forms, the trihydrate, the crystal form I and the crystal form II, were investigated by FT-IR and micro-Raman. Also data obtained by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray powder diffraction (XRPD) and hot-stage Raman spectroscopy are reported. Finally, quantum mechanical calculations were performed by density functional theory (DFT) to assist the assignment of spectroscopic experimental bands. For the first time, the ampicillin molecule in its zwitterionic form was studied at the B3LYP/aug-cc-pVDZ level and the corresponding theoretical vibrational spectra were computed. In fact, ampicillin in the crystal is in zwitterionic form and concentrations of this same form are quite relevant in solutions at physiological pH. Experimental and theoretical results allowed identification of specific features for polymorph characterization. Bands typical of the different polymorphs are identified both in IR and Raman spectra: in particular in the NH stretching region (IR), in the amide I+δNH region (both techniques), in the 1520-1490cm(-1) region (IR), in the 1320-1300cm(-1) and 1280-1220cm(-1) (IR), in the 1200-1170cm(-1) (Raman), in the amide V region (IR), and, finally, in the 715-640cm(-1) and 220-200cm(-1) (Raman). Interconversion among different polymorphs was investigated by hot-stage Raman spectroscopy and thermal analysis, clarifying the complex pattern of transformations undergone as a function of temperature and heating rate. In particular, DSC scans show how the trihydrate crystals transform into anhydrous forms on heating. Finally, stability tests demonstrated, after a two years period, that no transformation or degradation of the polymorphs occurred.

  18. Oxidation Mechanism of Molybdenite Concentrate

    Science.gov (United States)

    Utigard, T.

    2009-08-01

    The oxidation mechanism of a commercial molybdenum concentrate was investigated up to 650 °C using thermal analysis. Upon introduction of air, the molybdenite concentrate started to lose mass due to the oxidation of MoS2 to form molybdenum oxide and SO2. After a rapid mass loss, this was followed by a period of mass gain due to the oxidation of MoO2 to MoO3. The solid-state reaction between MoS2 and MoO3 to form MoO2 was also found to take place. Initially, as air is introduced, the rate is controlled by gas-phase diffusion of oxygen to the reaction surface. With time, as the surfaces of the MoS2 particles become oxidized and the rates start to slow, MoO3 starts to form. This generally leads to a mass gain as well as a slow down in oxidation rate due to the formation of a fairly dense MoO3 product layer. The timing of the various reactions was very dependent on the actual experimental conditions such as sample mass, gas flow rate, and heating rates.

  19. Micro metal forming

    CERN Document Server

    2013-01-01

    Micro Metal Forming, i. e. forming of parts and features with dimensions below 1 mm, is a young area of research in the wide field of metal forming technologies, expanding the limits for applying metal forming towards micro technology. The essential challenges arise from the reduced geometrical size and the increased lot size. In order to enable potential users to apply micro metal forming in production, information about the following topics are given: tribological behavior: friction between tool and work piece as well as tool wear mechanical behavior: strength and formability of the work piece material, durability of the work pieces size effects: basic description of effects occurring due to the fact, that the quantitative relation between different features changes with decreasing size process windows and limits for forming processes tool making methods numerical modeling of processes and process chains quality assurance and metrology All topics are discussed with respect to the questions relevant to micro...

  20. Unified form language

    DEFF Research Database (Denmark)

    Alnæs, Martin S.; Logg, Anders; Ølgaard, Kristian Breum;

    2014-01-01

    We present the Unied Form Language (UFL), which is a domain-specic language for representing weak formulations of partial dierential equations with a view to numerical approximation. Features of UFL include support for variational forms and functionals, automatic dierentiation of forms and expres......We present the Unied Form Language (UFL), which is a domain-specic language for representing weak formulations of partial dierential equations with a view to numerical approximation. Features of UFL include support for variational forms and functionals, automatic dierentiation of forms...... and expressions, arbitrary function space hierarchies for multi-eld problems, general dierential operators and exible tensor algebra. With these features, UFL has been used to eortlessly express nite element methods for complex systems of partial dierential equations in near-mathematical notation, resulting...

  1. Regarding proton form factors

    OpenAIRE

    Bloch, J. C. R.; Krassnigg, A.; Roberts, C. D.

    2003-01-01

    The proton's elastic electromagnetic form factors are calculated using an Ansatz for the nucleon's Poincare' covariant Faddeev amplitude that only retains scalar diquark correlations. A spectator approximation is employed for the current. On the domain of q^2 accessible in modern precision experiments these form factors are a sensitive probe of nonperturbative strong interaction dynamics. The ratio of Pauli and Dirac form factors can provide realistic constraints on models of the nucleon and ...

  2. FLOW FORMING OF AEROENGINEMATERIALS

    OpenAIRE

    Kubilay, Ceylan

    2014-01-01

    Flow forming is a fairly new technique used for the production of dimensionallyaccurate near net shaped hollow components. The process has many advantagessuch as cost effectiveness and eliminating further operations like welding, machin-ing, etc. This study focuses on the characterization of flow formed componentsto understand the process. Flow formed components are composed of differentreductions and characterization techniques are applied to reveal the resulting mi-crostructural differences...

  3. Fractional Differential Forms

    OpenAIRE

    Cotrill-Shepherd, Kathleen; NAber, Mark

    2003-01-01

    A generalization of exterior calculus is considered by allowing the partial derivatives in the exterior derivative to assume fractional orders. That is, a fractional exterior derivative is defined. This is found to generate new vector spaces of finite and infinite dimension, fractional differential form spaces. The definitions of closed and exact forms are extended to the new fractional form spaces with closure and integrability conditions worked out for a special case. Coordinate transformat...

  4. Cooperative Station History Forms

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Various forms, photographs and correspondence documenting the history of Cooperative station instrumentation, location changes, inspections, and...

  5. PowerForms

    DEFF Research Database (Denmark)

    Brabrand, Claus; Møller, Anders; Ricky, Mikkel;

    2000-01-01

    such validation. Today, CGI programmers often use Perl libraries for simple server-side validation or program customized JavaScript solutions for client-side validation. We present PowerForms, which is an add-on to HTML forms that allows a purely declarative specification of input formats and sophisticated...... interdependencies of form fields. While our work may be seen as inspiration for a future extension of HTML, it is also available for CGI programmers today through a preprocessor that translates a PowerForms document into a combination of standard HTML and JavaScript that works on all combinations of platforms...

  6. Automated solvent concentrator

    Science.gov (United States)

    Griffith, J. S.; Stuart, J. L.

    1976-01-01

    Designed for automated drug identification system (AUDRI), device increases concentration by 100. Sample is first filtered, removing particulate contaminants and reducing water content of sample. Sample is extracted from filtered residue by specific solvent. Concentrator provides input material to analysis subsystem.

  7. Method of forming nanodielectrics

    Science.gov (United States)

    Tuncer, Enis [Knoxville, TN; Polyzos, Georgios [Oak Ridge, TN

    2014-01-07

    A method of making a nanoparticle filled dielectric material. The method includes mixing nanoparticle precursors with a polymer material and reacting the nanoparticle mixed with the polymer material to form nanoparticles dispersed within the polymer material to form a dielectric composite.

  8. Mastering HTML5 forms

    CERN Document Server

    Gupta, Gaurav

    2013-01-01

    This tutorial will show you how to create stylish forms, not only visually appealing, but interactive and customized, in order to gather valuable user inputs and information.Enhance your skills in building responsive and dynamic web forms using HTML5, CSS3, and related technologies. All you need is a basic understanding of HTML and PHP.

  9. Baryon form factors

    CERN Document Server

    Kubis, B; Meißner, Ulf G; Mei{\\ss}ner, Ulf-G.

    1999-01-01

    We calculate the form factors of the baryon octet in the framework of heavy baryon chiral perturbation theory. The calculated charge radius of the show that kaon loop effects can play a significant role in the neutron electric form factor. Furthermore. we derive generalized Caldi-Pagels relations between various charge radii which are free of chiral loop effects.

  10. Forming of Laminates

    NARCIS (Netherlands)

    De Jong, T.W.

    2004-01-01

    Fibre-Metal-Laminates have excellent properties for aerospace applications, with GLARE as an example. The metal layers inside the laminate provide permanent plastic deformations for the whole laminate; in principle Fibre-Metal-Laminates can be formed with common sheet metal forming processes. The d

  11. From Figure to Form

    DEFF Research Database (Denmark)

    Hansen, Vagn Lundsgaard

    1999-01-01

    The ancient Greeks were convinced that the universe is structured according to mathematical laws. The present article describes geometrical aspects of this philosophy and concentrates in particular on the interplay between the concrete and the abstract side of geometry....

  12. Concentrating photovoltaic solar panel

    Science.gov (United States)

    Cashion, Steven A; Bowser, Michael R; Farrelly, Mark B; Hines, Braden E; Holmes, Howard C; Johnson, Jr., Richard L; Russell, Richard J; Turk, Michael F

    2014-04-15

    The present invention relates to photovoltaic power systems, photovoltaic concentrator modules, and related methods. In particular, the present invention features concentrator modules having interior points of attachment for an articulating mechanism and/or an articulating mechanism that has a unique arrangement of chassis members so as to isolate bending, etc. from being transferred among the chassis members. The present invention also features adjustable solar panel mounting features and/or mounting features with two or more degrees of freedom. The present invention also features a mechanical fastener for secondary optics in a concentrator module.

  13. Concentrating solar power

    International Nuclear Information System (INIS)

    This annual evaluation is a synthesis of works published in 2006. Comparisons are presented between the wind power performances and European Commission White Paper and Biomass action plan objectives. After having been blocked for a long time in its development, the concentrating solar power sector is undergoing a full revival today due to the falling costs, more effective technologies and policies sensitive to environmental questions. The USA concentrates today practically all of the installed concentrating solar power capacity in the world. But the sector is now also being carried by Spain. (A.L.B.)

  14. FormCalc 7

    CERN Document Server

    Agrawal, S; Mirabella, E

    2011-01-01

    We present additions and improvements in Version 7 of FormCalc, most notably analytic tensor reduction, choice of OPP methods, and MSSM initialization via FeynHiggs, as well as a parallelized Cuba library for numerical integration.

  15. Nucleon Form Factors

    Energy Technology Data Exchange (ETDEWEB)

    Cornelis de Jager

    2004-09-01

    The experimental and theoretical status of elastic electron scattering from the nucleon is reviewed. As a consequence of new experimental facilities, data of unprecedented precision have recently become available for the electromagnetic and the strange form factors of the nucleon.

  16. VMS forms Output Tables

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These output tables contain parsed and format validated data from the various VMS forms that are sent from any given vessel, while at sea, from the VMS devices on...

  17. Getting in-formed

    DEFF Research Database (Denmark)

    Hansbøl, Mikala

    det vi undersøger på form gennem vores beskrivelser. Paperet tager afsæt i empiriske eksempler fra et postdoc projekt om et såkaldt 'serious game' - Mingoville. Projektet følger circuleringer og etableringer af Mingoville 'på en global markedsplads'. I paperet diskuteres hvordan vi som forskere samler....../performer de fænomener vi forsker i. Aktør-Netværks-Teoretiker Bruno Latour (2005) pointerer at enhver beskrivelse også er en form for forklaring. En form for forklaring, der putter ting ind i et skript og dermed også putter ting på form. Paperet diskuterer to tilgange til at gøre serious games og derved skabe viden om...... engagementer med disse fænomener i serious games forskning: experimentel og etnografisk....

  18. NOAA Form 370 Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data set contains information from submitted NOAA Form 370s, also known as the Fisheries Certificate of Origin, for imported shipments of frozen and/or...

  19. FORM, Diagrams and Topologies

    CERN Document Server

    Herzog, Franz; Ueda, Takahiro; Vermaseren, J A M; Vogt, Andreas

    2016-01-01

    We discuss a number of FORM features that are essential in the automatic processing of very large numbers of diagrams as used in the Forcer program for 4-loop massless propagator diagrams. Most of these features are new.

  20. MAPS Appraisal Report Form

    CERN Multimedia

    HR Department

    2005-01-01

    As announced in Weekly Bulletin 48/2004, from now onwards, the paper MAPS appraisal report form has been replaced by an electronic form, which is available via EDH (on the EDH desktop under Other Tasks / HR & Training) No changes have been made to the contents of the form. Practical information will be available on the web page http://cern.ch/ais/projs/forms/maps/info.htm, and information meetings will be held on the following dates: 18 January 2005: MAIN AUDITORIUM (500-1-001) from 14:00 to 15:30. 20 January 2005: AB AUDITORIUM II (864-1-D02) from14:00 to 15:30. 24 January 2005: AT AUDITORIUM (30-7-018) from 10:00 to 11:30. Human Resources Department Tel. 73566

  1. Access Customized Forms

    OpenAIRE

    Cosma Emil; Jeflea Victor

    2010-01-01

    By using Word, Excel or PowerPoint one can automate routine operations using the VBA language (Visual Basic for Applications). This language is also used in Access, allowing access to data stored in tables or queries. Thus, Access and VBA resources can be used together. Access is designed for programming forms and reports (among other things), so there won’t be found any of the VBA editor’s specific forms.

  2. Electromagetic proton form factors

    OpenAIRE

    Hussein, M Y

    2006-01-01

    The electromagnetic form factors are crucial to our understanding of the proton internal structure, and thus provide a strong constraint of the distributions of the charge and magnetization current within the proton. We adopted the quark-parton model for calculating and understanding the charge structure of the proton interms of the electromagnetic form factors. A remarkable agreement with the available experimental evidence is found.

  3. The Literary Form

    OpenAIRE

    Compagnon, Antoine

    2015-01-01

    Wondering if there was anything new that could be said about literary forms, styles and genres, I was pleasantly surprised to notice that automated word processing, with its iterative review and algorithmic method, suggests the possibility of statistically surveying literary styles and genres. Digital Humanities, which are poorly developed in France, could contribute to the analysis of literary forms and the renewal of the theory of genres. As is often the case, it was while seeking to reso...

  4. Rheology of concentrated biomass

    Science.gov (United States)

    Samaniuk, J. R.; Wang, J.; Root, T. W.; Scott, C. T.; Klingenberg, D. J.

    2011-12-01

    Economic processing of lignocellulosic biomass requires handling the biomass at high solids concentration. This creates challenges because concentrated biomass behaves as a Bingham-like material with large yield stresses. Here we employ torque rheometry to measure the rheological properties of concentrated lignocellulosic biomass (corn stover). Yield stresses obtained using torque rheometry agree with those obtained using other rheometric methods, but torque rheometry can be used at much larger solids concentration (weight fractions of insoluble solids greater than 0.2). Yield stresses decrease with severity of hydrolysis, decrease when water-soluble polymers are added (for nonhydrolyzed biomass), and increase with particle length. Experimental results are qualitatively consistent with those obtained from particle-level simulations.

  5. FormFlavor Manual

    CERN Document Server

    Evans, Jared A

    2016-01-01

    This manual describes the usage and structure of FormFlavor, a Mathematica-based tool for computing a broad list of flavor and CP observables in general new physics models. Based on the powerful machinery of FeynArts and FormCalc, FormFlavor calculates the one-loop Wilson coefficients of the dimension 5 and 6 Standard Model effective Lagrangian entirely from scratch. These Wilson coefficients are then evolved down to the low scale using one-loop QCD RGEs, where they are transformed into flavor and CP observables. The last step is accomplished using a model-independent, largely stand-alone package called FFObservables that is included with FormFlavor. The SM predictions in FFObservables include up-to-date references and accurate current predictions. Using the functions and modular structure provided by FormFlavor, it is straightforward to add new observables. Currently, FormFlavor is set up to perform these calculations for the general, non-MFV MSSM, but in principle it can be generalized to arbitrary FeynArts...

  6. Concentrated poverty in Milwaukee

    OpenAIRE

    Jeremiah P. Boyle

    2009-01-01

    Hurricane Katrina and its aftermath created a renewed awareness of the unique isolation and vulnerability of people who live in communities where poverty concentrates and persists. The Federal Reserve’s Community Affairs staff partnered with the Brookings Institution to re-examine our understanding of concentrated poverty – defined as areas where at least 40 percent of the population lives below the poverty line.

  7. Workplace Concentration of Immigrants

    OpenAIRE

    Monica I. Garcia-Perez; Fredrik Andersson; John Haltiwanger; Fredrik Kristin McCue; Seth Sanders

    2014-01-01

    To what extent do immigrants and the native-born work in separate workplaces? Do worker and firm characteristics explain the degree of workplace concentration? We explore these questions using a matched employer-employee database that extensively covers employers in selected MSAs. We find that immigrants are much more likely to have immigrant coworkers than are natives, and are particularly likely to work with their compatriots. We find much higher levels of concentration for small businesses...

  8. 氮素形态和氮水平对烟草氮、磷、钾、氯积累分配的影响%Effect of Nitrogen Form and Concentration on Distribution of Nitrogen, Phosphorus, Potassium and Chlorine in Different Organs of Tobacco

    Institute of Scientific and Technical Information of China (English)

    杨秋云; 王国峰; 黄向东; 介晓磊; 刘世亮; 化党领

    2011-01-01

    为了解不同氮素形态和氮水平对烟草吸收矿质元素的影响,开展了营养液栽培试验.结果表明:纯硝态氮供应的叶片氮、磷含量随氮质量浓度增加而降低;有铵参与供氮的叶片氮、磷含量随氮质量浓度的增加而增加;叶片钾含量随总氮供应变化的规律不同于氮、磷,其在铵硝比5∶5之前随氮质量浓度的增加而降低,在铵硝比达到7∶3之后随氮质量浓度增加而增加,以铵硝比0∶10并氮质量浓度35 mg/L时取得叶片最高钾含量(6.32%),在铵硝比10∶0并氮质量浓度为35 mg/L时取得最低钾含量(3.19%);叶片氯含量有随铵硝比增大而提高的趋势.随铵硝比增加,叶片氮、磷、钾、氯和茎中氮、磷、钾积累量降低,铵硝比相同时,随氮质量浓度增加,钾积累量增加,叶片钾积累量在铵硝比0∶ 10并氮质量浓度140 mg/L时取得最高积累量1543.57 mg/株;根氮、磷积累量在铵硝比7∶3及以下,随氮质量浓度增加而增加,根钾积累量随供氮改变没有明显变化规律.叶片中氮、磷、钾含量和积累量均高于茎、根中氮、磷、钾含量和积累量.研究认为:铵态氮有利于叶片磷、氯积累,不利于叶片钾积累;硝态氮有利于叶片钾积累,不利于叶片磷、氯积累,在较高氮质量浓度下不利于叶片氮积累.%For understanding the effect of two forms of nitrogen(N) and nitrogen concentration on absorption of main mineral elements by different organs in tobacco, outdoor hydroponics were carried out. The conclusions were as follows. In leafs, N and phosphorus(P) content increased with N concentration decreasing at only nitrate-N, and increased with both ammonium and nitrate supplement. The trend of potassium(K) content changing with N were different with N and P. The content of K decreased with N rising below the ratio of 5: 5.and achieved the highest content of6. 32% at 0: 10 of ammonium/nitrate ratio simultaneously at 35mg/L of N

  9. Parabolic dish photovoltaic concentrator development

    Science.gov (United States)

    Beninga, K.; Davenport, R.; Featherby, M.; Sandubrae, J.; Walcott, K.

    1991-05-01

    Science Applications International Corporation (SAIC) and Tactical Fabs, Inc. (TFI) have fabricated a prototype parabolic dish photovoltaic (PV) concentrator system to demonstrate the functionality of this approach. A 1.5 m diameter parabolic dish was fabricated of a polyester/fiberglass composite, with a silvered polymer reflective surface. An innovative receiver cooling system used outward radial flow of cooling water in a narrow passage. This configuration matches the heat transfer capability of the cooling system to the flux profile on the PV receiver, minimizing temperature variations across the receiver. The photovoltaic cells used in the system were a new, TFI-proprietary design. Interleaved contacts form a bi-polar, rear-contact cell configuration. Because the electrical contacts are made on the rear of the cells, cells can be close-packed to form receiver arrays of arbitrary shape and size. Optical testing of the dish concentrator was performed by SAIC, SERI, and Sandia National Labs. The dish concentrator, designed for solar thermal applications, had a tight focal spot but exhibited flux non-uniformities away from the focal plane. Thermal testing of the receiver cooling system was performed with excellent success. Single PV cells, 4-cell blocks, and 144-cell receiver modules were built and tested. The cells successfully demonstrated the TFI design concept, but due to cell processing problems their efficiency was very low. Sources of the processing problems were identified and solutions were proposed, but funding limitations precluded further cell production. Operation of the complete PV dish system was conducted, and the functionality of the system was demonstrated. However, low cell efficiencies and receiver plane flux non-uniformities caused the system performance to be very low. These problems are not generic to the concept, and solutions to them proposed.

  10. Combinational concentration gradient confinement through stagnation flow.

    Science.gov (United States)

    Alicia, Toh G G; Yang, Chun; Wang, Zhiping; Nguyen, Nam-Trung

    2016-01-21

    Concentration gradient generation in microfluidics is typically constrained by two conflicting mass transport requirements: short characteristic times (τ) for precise temporal control of concentration gradients but at the expense of high flow rates and hence, high flow shear stresses (σ). To decouple the limitations from these parameters, here we propose the use of stagnation flows to confine concentration gradients within large velocity gradients that surround the stagnation point. We developed a modified cross-slot (MCS) device capable of feeding binary and combinational concentration sources in stagnation flows. We show that across the velocity well, source-sink pairs can form permanent concentration gradients. As source-sink concentration pairs are continuously supplied to the MCS, a permanently stable concentration gradient can be generated. Tuning the flow rates directly controls the velocity gradients, and hence the stagnation point location, allowing the confined concentration gradient to be focused. In addition, the flow rate ratio within the MCS rapidly controls (τ ∼ 50 ms) the location of the stagnation point and the confined combinational concentration gradients at low flow shear (0.2 Pa < σ < 2.9 Pa). The MCS device described in this study establishes the method for using stagnation flows to rapidly generate and position low shear combinational concentration gradients for shear sensitive biological assays. PMID:26671507

  11. Racial Harassment, Ethnic Concentration and Economic Conditions

    OpenAIRE

    Dustmann, Christian; Fabbri, Francesca; Preston, Ian

    2004-01-01

    In this paper, we analyse the association between the spatial concentration of ethnic minorities and racial harassment. Ethnic concentration relates to racial harassment through at least three channels: hostility in the attitudes of majority individuals that finds expression in harassment behaviour, the probability that minority individuals meet majority individuals, and the cost of expressing hostility aggressively. Thus, harassment cannot simply be modelled as a stronger form of hostility. ...

  12. Density, form and performance

    NARCIS (Netherlands)

    De Jong, P.

    2011-01-01

    A redefinition of building economics towards sustainability will include the spatial approach of green field investments and most of all necessary intensification of brown field development. For large parts of Western Europe and the US the latter will be, according to economic principles of concentr

  13. Methods for forming particles

    Energy Technology Data Exchange (ETDEWEB)

    Fox, Robert V.; Zhang, Fengyan; Rodriguez, Rene G.; Pak, Joshua J.; Sun, Chivin

    2016-06-21

    Single source precursors or pre-copolymers of single source precursors are subjected to microwave radiation to form particles of a I-III-VI.sub.2 material. Such particles may be formed in a wurtzite phase and may be converted to a chalcopyrite phase by, for example, exposure to heat. The particles in the wurtzite phase may have a substantially hexagonal shape that enables stacking into ordered layers. The particles in the wurtzite phase may be mixed with particles in the chalcopyrite phase (i.e., chalcopyrite nanoparticles) that may fill voids within the ordered layers of the particles in the wurtzite phase thus produce films with good coverage. In some embodiments, the methods are used to form layers of semiconductor materials comprising a I-III-VI.sub.2 material. Devices such as, for example, thin-film solar cells may be fabricated using such methods.

  14. The Microwave Concentrator Design and Study on Concentrating Apple Juice

    OpenAIRE

    Geng Yuefeng; Ge Xinfeng

    2014-01-01

    Microwave concentrating device on fresh apple juice is designed in order to increase concentrating fresh apple juice efficiency and microwave concentrating process on fresh apple juice were studied. The designed microwave concentrator contains microwave generator, dehumidification system, electrical cabinet, parabolic waveguide, control system, microwave leakage inhibited mechanism and other components. The concentrating experiment is carried by the designed concentrator, from the setting-to-...

  15. How Do Friendships Form?

    OpenAIRE

    Bruce Sacerdote; David Marmaros

    2005-01-01

    We examine how people form social networks among their peers. We use a unique dataset that tells us the volume of email between any two people in the sample. The data are from students and recent graduates of Dartmouth College. First year students interact with peers in their immediate proximity and form long term friendships with a subset of these people. This result is consistent with a model in which the expected value of interacting with an unknown person is low (making traveling solely t...

  16. Thermal cloak-concentrator

    Science.gov (United States)

    Shen, Xiangying; Li, Ying; Jiang, Chaoran; Ni, Yushan; Huang, Jiping

    2016-07-01

    For macroscopically manipulating heat flow at will, thermal metamaterials have opened a practical way, which possesses a single function, such as either cloaking or concentrating the flow of heat even though environmental temperature varies. By developing a theory of transformation heat transfer for multiple functions, here we introduce the concept of intelligent thermal metamaterials with a dual function, which is in contrast to the existing thermal metamaterials with single functions. By assembling homogeneous isotropic materials and shape-memory alloys, we experimentally fabricate a kind of intelligent thermal metamaterials, which can automatically change from a cloak (or concentrator) to a concentrator (or cloak) when the environmental temperature changes. This work paves an efficient way for a controllable gradient of heat, and also provides guidance both for arbitrarily manipulating the flow of heat and for efficiently designing similar intelligent metamaterials in other fields.

  17. Pollutant concentrations in placenta

    DEFF Research Database (Denmark)

    Leino, O.; Kiviranta, H.; Karjalainen, A. K.;

    2013-01-01

    Unborn children are exposed to environmental pollutants via the placenta, and there is a causal relationship between maternal intake of pollutants and fetal exposure. Placental examination is an effective way for acquiring data for estimating fetal exposure. We analyzed the concentrations of 104...... congeners of persistent organic pollutants, seven organotin compounds, five heavy metals, and methylmercury in 130 randomly selected placentas. Additionally, we examined similarities between pollutant concentrations by analyzing correlations between their placental concentrations. Our results yield new...... information for conducting contaminant risk assessments for the prenatal period. Out of the 117 individual persistent organic pollutants or metals assayed, 46 could be detected in more than half of the placentas. Moreover, dichlorodiphenyldichloroethylene (p,p'-DDE) was found in all placentas. The data...

  18. Photovoltaic solar concentrator

    Energy Technology Data Exchange (ETDEWEB)

    Nielson, Gregory N.; Gupta, Vipin P.; Okandan, Murat; Watts, Michael R.

    2016-03-15

    A photovoltaic solar concentrator is disclosed with one or more transverse-junction solar cells (also termed point contact solar cells) and a lens located above each solar cell to concentrate sunlight onto the solar cell to generate electricity. Piezoelectric actuators tilt or translate each lens to track the sun using a feedback-control circuit which senses the electricity generated by one or more of the solar cells. The piezoelectric actuators can be coupled through a displacement-multiplier linkage to provide an increased range of movement of each lens. Each lens in the solar concentrator can be supported on a frame (also termed a tilt plate) having three legs, with the movement of the legs being controlled by the piezoelectric actuators.

  19. Photovoltaic solar concentrator

    Science.gov (United States)

    Nielson, Gregory N.; Okandan, Murat; Resnick, Paul J.; Cruz-Campa, Jose Luis

    2012-12-11

    A photovoltaic solar concentrator is disclosed with one or more transverse-junction solar cells (also termed point contact solar cells) and a lens located above each solar cell to concentrate sunlight onto the solar cell to generate electricity. Piezoelectric actuators tilt or translate each lens to track the sun using a feedback-control circuit which senses the electricity generated by one or more of the solar cells. The piezoelectric actuators can be coupled through a displacement-multiplier linkage to provide an increased range of movement of each lens. Each lens in the solar concentrator can be supported on a frame (also termed a tilt plate) having three legs, with the movement of the legs being controlled by the piezoelectric actuators.

  20. Vacancy Concentration in Ice

    DEFF Research Database (Denmark)

    Mogensen, O. E.; Eldrup, Morten Mostgaard

    1977-01-01

    Based on the diffusion constant for self-diffusion in ice, which is believed to take place by a vacancy mechanism, we estimate the relative vacancy concentration near the melting point to be at least ∼ 10−6, i.e. much higher than previous estimates of about 10−10.......Based on the diffusion constant for self-diffusion in ice, which is believed to take place by a vacancy mechanism, we estimate the relative vacancy concentration near the melting point to be at least ∼ 10−6, i.e. much higher than previous estimates of about 10−10....

  1. Concentrated loads on concrete

    DEFF Research Database (Denmark)

    Lorenzen, Karen Grøndahl; Nielsen, Mogens Peter

    1997-01-01

    This report deals with concentrated loads on concrete.A new upper bound solution in the axisymmetrical case of a point load in the center of the end face of a cylinder is developed.Based on previous work dealing with failure mechanisms and upper bound solutions, new approximate formulas are devel......This report deals with concentrated loads on concrete.A new upper bound solution in the axisymmetrical case of a point load in the center of the end face of a cylinder is developed.Based on previous work dealing with failure mechanisms and upper bound solutions, new approximate formulas...

  2. DSMTS: A novel linear PV concentrator

    Energy Technology Data Exchange (ETDEWEB)

    Benitez, P.; Mohedano, R.; Minano, J.C. [Univ. Politecnica, Madrid (Spain). Inst. de Energia Solar

    1997-12-31

    A new linear nonimaging concentrator suitable for one-axis tracking operation, the DSMTS, is presented. It has reflective primary optics and reflective/refractive secondary optics. However, all the optical components and the solar cells form a single piece in a DSMTS, which simplifies the system: housing and assembling structure are not needed, and the heat sinks can coincide with the supporting structure. A DSMTS designed for an acceptance angle of {+-}0.72{degree} gets a geometrical concentration of 100x. For a geometrical concentration of 30x, an acceptance of {+-}2.55 degrees is obtained. This high acceptance is useful to relax the optics, structure and mounting accuracies.

  3. Computational algorithm for molybdenite concentrate annealing

    International Nuclear Information System (INIS)

    Computational algorithm is presented for annealing of molybdenite concentrate with granulated return dust and that of granulated molybdenite concentrate. The algorithm differs from the known analogies for sulphide raw material annealing by including the calculation of return dust mass in stationary annealing; the latter quantity varies form the return dust mass value obtained in the first iteration step. Masses of solid products are determined by distribution of concentrate annealing products, including return dust and benthonite. The algorithm is applied to computations for annealing of other sulphide materials. 3 refs

  4. Low temperature waste form process intensification

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K. M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Cozzi, A. D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Hansen, E. K. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Hill, K. A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-09-30

    This study successfully demonstrated process intensification of low temperature waste form production. Modifications were made to the dry blend composition to enable a 50% increase in waste concentration, thus allowing for a significant reduction in disposal volume and associated costs. Properties measurements showed that the advanced waste form can be produced using existing equipment and processes. Performance of the waste form was equivalent or better than the current baseline, with approximately double the amount of waste incorporation. The results demonstrate the feasibility of significantly accelerating low level waste immobilization missions across the DOE complex and at environmental remediation sites worldwide.

  5. On Quadratic Differential Forms

    NARCIS (Netherlands)

    Willems, J.C.; Trentelman, H.L.

    1998-01-01

    This paper develops a theory around the notion of quadratic differential forms in the context of linear differential systems. In many applications, we need to not only understand the behavior of the system variables but also the behavior of certain functionals of these variables. The obvious cases w

  6. Metal forming and lubrication

    DEFF Research Database (Denmark)

    Bay, Niels

    2000-01-01

    Lubrication is essential in most metal forming processes. The lubricant film has two basic functions, [1]: i. to separate the work piece and tool surfaces and ii. to cool the workpiece and the tool. Separation of the two surfaces implies lower friction facilitating deformation and lowering the tool...

  7. Incentive to Form

    DEFF Research Database (Denmark)

    Thomsen, Bente Dahl; Madsen, Klaus

    2011-01-01

    Projektet ’Incitament til Form' har identificeret en række tematiske angreb på formstudier - i stærkt papir – som skaber nye former, hvor af en eller flere ofte indeholder stærkere kvaliteter end udgangspunktet. Incitamenter er, i denne sammenhæng, former skabt ved foldning over variationer af li...

  8. Many Forms of Culture

    Science.gov (United States)

    Cohen, Adam B.

    2009-01-01

    Psychologists interested in culture have focused primarily on East-West differences in individualism-collectivism, or independent-interdependent self-construal. As important as this dimension is, there are many other forms of culture with many dimensions of cultural variability. Selecting from among the many understudied cultures in psychology,…

  9. Measuring urban form

    NARCIS (Netherlands)

    Berghauser Pont, M.Y.

    2011-01-01

    For many, the notion of ‘measuring urban form’ will sound disturbing. Urban form is about visual images of cities, experiences, feelings, memories of place, thoughts and intellectual constructs anchored in the realm of the arts and the humanities. Anne Vernez Moudon however gives in the paper Urbani

  10. Nucleon Form Factors

    Energy Technology Data Exchange (ETDEWEB)

    Kees de Jager

    2002-10-01

    A review of data on the nucleon electro-weak form factors in the space-like region is presented. Recent results from experiments using polarized beams and either polarized targets or nucleon recoil polarimeters have yielded a significant improvement on the precision of the electromagnetic data obtained with the traditional Rosenbluth separation. An outlook is presented of planned experiments.

  11. Image forming apparatus

    DEFF Research Database (Denmark)

    2005-01-01

    An image H(x, y) for displaying a target image G(x, y) is displayed on a liquid-crystal display panel and illumination light from an illumination light source is made to pass therethrough to form an image on a PALSLM. Read light hv is radiated to the PALSLM and a phase-modulated light image alpha...

  12. Obtain of uranium concentrates from fertil liquids

    International Nuclear Information System (INIS)

    This research tried to encounter the form to remove uranium from the rock in the best way, for that it was used different process like leaching, extraction, concentration and precipitation. To leach the mineral was chosen basic leaching, using a mixture of carbonate-sodium bicarbonate, this method is more adequated for the basic nature of the mineral. In extraction was used specific uranium ionic interchanges, so was chosen a tertiary amine like Alamina 336. The concentration phase is intimately binding with the extraction by ionic interchange, for the capability of resine's extraction to obtain concentrated liquids. When the liquids were obtained with high concentration of uranium in the same time were purified and then were precipitated, for that we employed a precipitant agent like: Sodium hydroxide, Amonium hydroxide, Magnesium hydroxide, Hydrogen peroxide and phosphates. With all concentrates we obtain the YELLOW CAKE

  13. Evaluation of new indomethacin dosage forms.

    Science.gov (United States)

    Waller, E S

    1983-01-01

    Indomethacin, an indole derivative nonsteroidal anti-inflammatory drug, has been available since the early 1960s in gelatin capsules. In 1982, a sustained release product, Indocin SR, was marketed. Awaiting marketing approval is a unique controlled release form of indomethacin, Indos. The disposition of indomethacin includes enterohepatic cycling and extensive metabolism to inactive metabolites. Enterohepatic cycling makes interpretation of bioavailability estimates of indomethacin dosage forms difficult. The relationship of indomethacin plasma concentration to therapeutic effects and side effects is inconclusive. It appears in vivo prostaglandin inhibition occurs at very low plasma concentrations that are achievable with all available dosage forms. Indocin SR is a sustained release capsule of indomethacin designed to deliver 25 mg of drug immediately and 50 mg gradually. Absolute bioavailability of the product is 80%. The plasma concentration-time curves do not show good sustained release characteristics; after four hours plasma concentrations resemble those seen with a single dose of regular capsule. The cost compared with Indocin is competitive. Indos is a zero-order release form of indomethacin. It is a unique drug delivery system that shows good controlled release characteristics. Bioavailability is 85%. Both Indocin SR and Indos are apparently therapeutically equivalent to indomethacin capsules. In elderly patients, Indos has been shown to be associated with fewer side effects than Indocin. Both Indocin SR and Indos have the advantage of once or twice daily dosing.

  14. Drowning in concentrated syrup.

    Science.gov (United States)

    Talwar, Vandana; Sood, Nishant; Verma, P K

    2009-04-01

    Drowning is one of the two leading causes of accidental death in children. Most of the cases can be attributed to fresh or salt water drowning. We report an unusual case of acute respiratory distress syndrome in a one year old child following drowning in concentrated sugar syrup, in whom timely intervention and early supportive therapy resulted in a favorable outcome.

  15. Solar concentrator/absorber

    Science.gov (United States)

    Von Tiesenhausen, G. F.

    1976-01-01

    Collector/energy converter, consisting of dual-slope optical concentrator and counterflow thermal energy absorber, is attached to multiaxis support structure. Efficient over wide range of illumination levels, device may be used to generate high temperature steam, serve as solar powered dryer, or power absorption cycle cooler.

  16. The Form of Gentrification

    CERN Document Server

    Venerandi, Alessandro; Romice, Ombretta; Porta, Sergio

    2014-01-01

    Many socioeconomic studies have been carried out to explain the phenomenon of gentrification. Although results of these works shed light on the process around this phenomenon, a perspective which focuses on the relationship between city form and gentrification is still missing. With this paper we try to address this gap by studying and comparing, through classic methods of mathematical statistics, morphological features of five London gentrified neighbourhoods. Outcomes confirm that areas which have undergone gentrification display similar and recognizable morphological patterns in terms of urban type and geographical location of main and local roads as well as businesses. These initial results confirm findings from previous research in urban sociology, and highlight the role of urban form in contributing to shape dynamics of non-spatial nature in cities.

  17. Texture and sheet forming

    Energy Technology Data Exchange (ETDEWEB)

    Canova, G.R.; Kocks, U.F.; Fressengeas, C.; Dudzinski, D.; Lequeu, Ph.; Sornberger, G.

    1987-01-01

    The classical Marciniak-Kuczynski (Defect) theory, which consists in calculating the behavior of an initial defect in the sheet, in the form of a thin groove, is applied together with a full-constraints or relaxed-constraints theory of polycrystal viscoplasticity. Purpose of this is to investigate the effect of the induced texture on the Forming Limit Diagram (FLD), and the effect of grain shape as well. An alternative fast way of deriving FLD's is also proposed using a perturbation method. Comparisons are made between the results obtained by both Defect and Perturbation theories, in the case of ideal fcc rolling texture components, and in the case of polycrystals. 13 refs., 7 figs.

  18. Formed HIP Can Processing

    Energy Technology Data Exchange (ETDEWEB)

    Clarke, Kester Diederik [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-07-27

    The intent of this report is to document a procedure used at LANL for HIP bonding aluminum cladding to U-10Mo fuel foils using a formed HIP can for the Domestic Reactor Conversion program in the NNSA Office of Material, Management and Minimization, and provide some details that may not have been published elsewhere. The HIP process is based on the procedures that have been used to develop the formed HIP can process, including the baseline process developed at Idaho National Laboratory (INL). The HIP bonding cladding process development is summarized in the listed references. Further iterations with Babcock & Wilcox (B&W) to refine the process to meet production and facility requirements is expected.

  19. Low Temperature Sheet Forming

    Science.gov (United States)

    Voges-Schwieger, Kathrin; Hübner, Sven; Behrens, Bernd-Arno

    2011-05-01

    Metastable austenitic stainless steels change their lattice during forming operations by strain-induced alpha'-martensite formation. Temperatures below T = 20° C can accelerate the phase transformation while temperatures above T = 60° C may suppress the formation of martensite during the forming operation. In past investigations, the effect of high-strength martensitic regions in an austenitic ductile lattice was used in crash relevant parts for transportation vehicles. The local martensitic regions act as reinforcements leading to an increase in crash energy absorption. Moreover, they control the folding behavior as well as the force-distance-characteristic and increase the buckling resistance. This paper deals with a concerted thermomechanical drawing process to increase the local formation of alpha'-martensite caused by low temperatures.

  20. How semiconductor nanoplatelets form

    OpenAIRE

    Riedinger, Andreas; Ott, Florian D.; Mule, Aniket; Mazzotti, Sergio; Knuesel, Philippe N.; Kress, Stephan J. P.; Prins, Ferry; Erwin, Steven C.; Norris, David J.

    2016-01-01

    Colloidal nanoplatelets - quasi-two-dimensional sheets of semiconductor exhibiting efficient, spectrally pure fluorescence - form when liquid-phase syntheses of spherical quantum dots are modified. Despite intense interest in their properties, the mechanism behind their anisotropic shape and precise atomic-scale thickness remains unclear, and even counterintuitive when their crystal structure is isotropic. One commonly accepted explanation is that nanoclusters nucleate within molecular templa...

  1. Structure: form, beauty, space

    OpenAIRE

    O'Donovan, James

    2012-01-01

    non-peer-reviewed The objective of my thesis is to explore the various elements that make structure architecture. Through investigation into thinness, material, span, space and soundscape, I wish to create an architecture which can appeal to the senses and have value form many years to come. I propose to interrogate these qualities with the demanding programme of aircraft cargo and maintenance on the site of Shannon Airport, which is situated on the shannon estuary and to...

  2. Electrolyte Concentrates Treat Dehydration

    Science.gov (United States)

    2009-01-01

    Wellness Brands Inc. of Boulder, Colorado, exclusively licensed a unique electrolyte concentrate formula developed by Ames Research Center to treat and prevent dehydration in astronauts returning to Earth. Marketed as The Right Stuff, the company's NASA-derived formula is an ideal measure for athletes looking to combat dehydration and boost performance. Wellness Brands also plans to expand with products that make use of the formula's effective hydration properties to help treat conditions including heat stroke, altitude sickness, jet lag, and disease.

  3. Zirconia concentrate chlorination

    International Nuclear Information System (INIS)

    Chlorination experiments were conducted in order to study the kinetics of gasification of the zirconium oxide present in the zirconia concentrate. The variables studied are temperature (1173 to 1373 K), percentage of reducing agent (12 to 36%) and porosity (22 to 30%). The results indicated a greater influence of temperature and percentage of reducing agent as well as allowed the conclusion that a balance between the levels of these variables is an important factor in the appropriate chlorination conditions. (author)

  4. Concentrated solar thermoelectric generators

    OpenAIRE

    Baranowski, Lauryn L.; Snyder, G. Jeffrey; Toberer, Eric S.

    2012-01-01

    Solar thermoelectric generators (STEGs) are solid state heat engines that generate electricity from concentrated sunlight. In this paper, we develop a novel detailed balance model for STEGs and apply this model to both state-of-the-art and idealized materials. This model uses thermoelectric compatibility theory to provide analytic solutions to device efficiency in idealized materials with temperature-dependent properties. The results of this modeling allow us to predict maximum theoretical ST...

  5. Advanced forming technology

    Directory of Open Access Journals (Sweden)

    J. Kliber

    2016-10-01

    Full Text Available Forming is usually the final stage of metallurgical production of steel (90 % of the 1,7 billion tons of total steel production in the world and traditionally also largely of the products made of non-ferrous metals. Many procedures and methods exist and we will focus only on some of them. The aim is usually to achieve ultra-fine grained structure, the proper microstructure and (mechanical / electrical properties in innovative materials. The presented article mentions only some examples.

  6. Do naked singularities form?

    CERN Document Server

    Vaz, C; Vaz, Cenalo; Witten, Louis

    1995-01-01

    A naked singularity is formed by the collapse of a Sine-Gordon soliton in 1+1 dimensional dilaton gravity with a negative cosmological constant. We examine the quantum stress tensor resulting from the formation of the singularity. Consistent boundary conditions require that the incoming soliton is accompanied by a flux of incoming radiation across past null infinity, but neglecting the back reaction of the spacetime leads to the absurd conclusion that the total energy entering the system by the time the observer is able to receive information from the singularity is infinite. We conclude that the back reaction must prevent the formation of the naked singularity.

  7. Form Some Words

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Hey! The flowerpot (花盆) is a puzzle. You can see some English capital letters on the petals (花瓣) and on the flowerpot. Er! If you count, there are ten English capital letters. Some are the same. They are A, I, U, Rs, Es, Ts and L. After enjoying the pic- ture, finish a task. Please form words as many as you can. The rules are: Letters can only be used once for each time. Plurals, proper names (专有名词) do not count. OK! Start your work at once, please. Have fun!

  8. [Adhesive cutaneous pharmaceutical forms].

    Science.gov (United States)

    Gafiţanu, E; Matei, I; Mungiu, O C; Pavelescu, M; Mîndreci, I; Apostol, I; Ionescu, G

    1989-01-01

    The adhesive cutaneous pharmaceutical forms aimed to local action release the drug substance in view of a dermatological, traumatological, antirheumatic, cosmetic action. Two such preparations were obtained and their stability, consistency and pH were determined. The "in vitro" tests of their bioavailability revealed the dynamics of calcium ions release according to the associations of each preparation. The bioavailability determined by evaluating the pharmacological response demonstrated the antiinflammatory action obtained by the association of calcium ions with the components extracted from poplar muds. The therapeutical efficiency of the studied preparations has proved in the treatment of some sport injuries.

  9. Measurement of heme concentration.

    Science.gov (United States)

    Sinclair, P R; Gorman, N; Jacobs, J M

    2001-05-01

    Heme (iron protoporphyrin IX) is a prosthetic group for a number of hemoproteins in different tissues (e.g., hemoglobin, myoglobin, cytochrome P-450s, mitochondrial cytochromes, catalases, and peroxidases). Mutations in the biosynthetic pathway can affect the synthesis and/or degradation of heme. Several assays are provided in this unit for quantifying heme: a spectrophotometric assay based on the characteristic absorption spectrum of oxidized and reduced form of the hemochrome formed by replacing the nitrogen ligands with pyridine; a fluorescence assay based on removal of the iron by a heated, strong oxalic acid solution to produce fluorescent protoporphyrin; a reversed-phase HPLC assay to measure heme and intermediates in the synthetic pathway; and a radiometric assay to measure newly synthesized heme in tissue culture cells.

  10. Summary of Dissolved Concentration Limits

    Energy Technology Data Exchange (ETDEWEB)

    Yueting Chen

    2001-06-11

    According to the Technical Work Plan titled Technical Work Plan for Waste Form Degradation Process Model Report for SR (CRWMS M&O 2000a), the purpose of this study is to perform abstractions on solubility limits of radioactive elements based on the process-level information and thermodynamic databases provided by Natural Environment Program Operations (NEPO) and Waste Package Operations (WPO). The scope of this analysis is to produce solubility limits as functions, distributions, or constants for all transported radioactive elements identified by the Performance Assessment Operations (PAO) radioisotope screening. Results from an expert elicitation for solubility limits of most radioactive elements were used in the previous Total System Performance Assessments (TSPAs). However, the elicitation conducted in 1993 does not meet the criteria set forth by the U.S. Nuclear Regulatory Commission (NRC) due to lack of documentation and traceability (Kotra et al. 1996, Section 3). Therefore, at the Waste Form Abstraction Workshop held on February 2-4, 1999, at Albuquerque, New Mexico, the Yucca Mountain Site Characterization Project (YMP) decided to develop geochemical models to study solubility for the proposed Monitored Geologic Repository. WPO/NEPO is to develop process-level solubility models, including review and compilation of relevant thermodynamic data. PAO's responsibility is to perform abstractions based on the process models and chemical conditions and to produce solubility distributions or response surfaces applicable to the proposed repository. The results of this analysis and conceptual model will feed the performance assessment for Total System Performance Assessment--Site Recommendation (TSPA-SR) and Total System Performance Assessment--License Application (TSPA-LA), and to the Waste Form Degradation Process Model Report section on concentration limits.

  11. Concentrated Solar Thermoelectric Power

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Gang [MIT; Ren, Zhifeng [University of Houston

    2015-07-09

    The goal of this project is to demonstrate in the lab that solar thermoelectric generators (STEGs) can exceed 10% solar-to-electricity efficiency, and STEGs can be integrated with phase-change materials (PCM) for thermal storage, providing operation beyond daylight hours. This project achieved significant progress in many tasks necessary to achieving the overall project goals. An accurate Themoelectric Generator (TEG) model was developed, which included realistic treatment of contact materials, contact resistances and radiative losses. In terms of fabricating physical TEGs, high performance contact materials for skutterudite TE segments were developed, along with brazing and soldering methods to assemble segmented TEGs. Accurate measurement systems for determining device performance (in addition to just TE material performance) were built for this project and used to characterize our TEGs. From the optical components’ side, a spectrally selective cermet surface was developed with high solar absorptance and low thermal emittance, with thermal stability at high temperature. A measurement technique was also developed to determine absorptance and total hemispherical emittance at high temperature, and was used to characterize the fabricated spectrally selective surfaces. In addition, a novel reflective cavity was designed to reduce radiative absorber losses and achieve high receiver efficiency at low concentration ratios. A prototype cavity demonstrated that large reductions in radiative losses were possible through this technique. For the overall concentrating STEG system, a number of devices were fabricated and tested in a custom built test platform to characterize their efficiency performance. Additionally, testing was performed with integration of PCM thermal storage, and the storage time of the lab scale system was evaluated. Our latest testing results showed a STEG efficiency of 9.6%, indicating promising potential for high performance concentrated STEGs.

  12. Nanophotonic Luminescent Solar Concentrators

    CERN Document Server

    Rousseau, I

    2013-01-01

    We investigate the connection between photonic local density of states and luminescent solar concentrator (LSC) performance in two manufacturable nanocavity LSC structures, a bilayer slab and a slab photonic crystal. Finite-difference time-domain electromagnetic simulations show that the waveguided luminescence photon flux can be enhanced up to 30% for the photonic crystal design over a conventional LSC operating in the ray optic limit assuming the same number of excited lumophores. Further photonic engineering could realize an increase of up to one order of magnitude in the flux of waveguided luminescence.

  13. Theory of Concentrated Vortices

    DEFF Research Database (Denmark)

    Alekseenko, Sergey; Kuibin, Pavel; Okulov, Valery

    This book presents comprehensive and authoritative coverage of the wide field of concentrated vortices observed in nature and technique. The methods for research of their kinematics and dynamics are considered. Special attention is paid to the flows with helical symmetry. The authors have describ...... models of vortex structures used for interpretation of experimental data which serve as a ground for development of theoretical and numerical approaches to vortex investigation. Achievements in the fields of stability analysis, waves on vortices and vortex breakdown are also presented....

  14. Censored correlated cytokine concentrations

    DEFF Research Database (Denmark)

    Andersen, Andreas; Benn, Christine Stabell; Jørgensen, Mathias J;

    2013-01-01

    Interest in cytokines as markers for the function of the immune system is increasing. Methods quantifying cytokine concentrations are often subject to detection limits, which lead to non-detectable observations and censored distributions. When distributions are skewed, geometric mean ratios (GMRs...... for both homogeneous and inhomogeneous normal distributions. For skewed mixture and heavy-tailed distributions, they perform reasonably well if censoring is less than 30%. We recommend these methods to estimate GMRRs. At least one of the methods is available in Stata, R or SAS....

  15. Membrane distillation for milk concentration

    NARCIS (Netherlands)

    Moejes, S.N.; Romero Guzman, Maria; Hanemaaijer, J.H.; Barrera, K.H.; Feenstra, L.; Boxtel, van A.J.B.

    2015-01-01

    Membrane distillation is an emerging technology to concentrate liquid products while producing high quality water as permeate. Application for desalination has been studied extensively the past years, but membrane distillation has also potential to produce concentrated food products like concentrate

  16. Benchmarking concentrating photovoltaic systems

    Science.gov (United States)

    Duerr, Fabian; Muthirayan, Buvaneshwari; Meuret, Youri; Thienpont, Hugo

    2010-08-01

    Integral to photovoltaics is the need to provide improved economic viability. To achieve this goal, photovoltaic technology has to be able to harness more light at less cost. A large variety of concentrating photovoltaic concepts has provided cause for pursuit. To obtain a detailed profitability analysis, a flexible evaluation is crucial for benchmarking the cost-performance of this variety of concentrating photovoltaic concepts. To save time and capital, a way to estimate the cost-performance of a complete solar energy system is to use computer aided modeling. In this work a benchmark tool is introduced based on a modular programming concept. The overall implementation is done in MATLAB whereas Advanced Systems Analysis Program (ASAP) is used for ray tracing calculations. This allows for a flexible and extendable structuring of all important modules, namely an advanced source modeling including time and local dependence, and an advanced optical system analysis of various optical designs to obtain an evaluation of the figure of merit. An important figure of merit: the energy yield for a given photovoltaic system at a geographical position over a specific period, can be calculated.

  17. Nucleon Electromagnetic Form Factors

    Energy Technology Data Exchange (ETDEWEB)

    Marc Vanderhaeghen; Charles Perdrisat; Vina Punjabi

    2007-10-01

    There has been much activity in the measurement of the elastic electromagnetic proton and neutron form factors in the last decade, and the quality of the data has greatly improved by performing double polarization experiments, in comparison with previous unpolarized data. Here we review the experimental data base in view of the new results for the proton, and neutron, obtained at JLab, MAMI, and MIT-Bates. The rapid evolution of phenomenological models triggered by these high-precision experiments will be discussed, including the recent progress in the determination of the valence quark generalized parton distributions of the nucleon, as well as the steady rate of improvements made in the lattice QCD calculations.

  18. The forms of prophecy

    Directory of Open Access Journals (Sweden)

    Rayco González

    2013-11-01

    Full Text Available The prophecy is a kind of text holding therefore its own textual marks, differing from other kinds of texts. In order to do a discursive analysis of it, we must bring a semiotic study of its own possible forms. It includes its intertextual connections, as well as the use of typical tropos and topoi. Our aim is to describe the features of a kind of text that seems to appear in every well-known culture. Our analysis is limited to religious prophecies, showing mainly several examples from Judeo-Christian tradition, but also from other cultures, according to our line of argument. Amongst its features we find the use of allusion, forcing to any addressee to expand all possible interpretations. Likewise the prophecy seems to fulfill the double function of threat/promise, depending on each addressee.

  19. Circle of Form

    DEFF Research Database (Denmark)

    Jaeger, Thomas Arvid

    2012-01-01

    Teaching aesthetics belongs to one of the most flourishing part in education. The variety of methods, terminology and tradition differs from country to country, school to school and from person to person. The ability to make aesthetic judgments which are coherent is difficult because, we don’t have...... a common professional language like in mathematics, colour and music. The result is a weaker professionalism in the aesthetic competences compared to the professionalism and competences in other areas. A research project [1] on contrasts or opposites in form investigated the phenomenon in the fields...... of architecture, design, art, art theory, and perception. It was then obvious in related areas to look for systems or models which organized opposites. The colour system has the same fundamental dualistic structure based on complementary colours, on light and dark (black and white), cold and warm. Inspired...

  20. Pion form factor

    Energy Technology Data Exchange (ETDEWEB)

    Ryong Ji, C.; Pang, A.; Szczepaniak, A. [North Carolina State Univ., Raleigh, NC (United States)

    1994-04-01

    It is pointed out that the correct criterion to define the legal PQCD contribution to the exclusive processes in the lightcone perturbative expansion should be based on the large off-shellness of the lightcone energy in the intermediate states. In the lightcone perturbative QCD calculation of the pion form factor, the authors find that the legal PQCD contribution defined by the lightcone energy cut saturates in the smaller Q{sup 2} region compared to that defined by the gluon four-momentum square cut. This is due to the contribution by the highly off-energy-shell gluons in the end point regions of the phase space, indicating that the gluon four-momentum-square cut may have cut too much to define the legal PQCD.

  1. 78 FR 58605 - Proposed Collection; Comment Request for Form 8453-EMP, Form 8453-F, Form 8453-FE, Form 8879-F...

    Science.gov (United States)

    2013-09-24

    ... Internal Revenue Service Proposed Collection; Comment Request for Form 8453-EMP, Form 8453-F, Form 8453-FE, Form 8879-F, and 8879-EMP. AGENCY: Internal Revenue Service (IRS), Treasury. ACTION: Notice and request... comments concerning Form 8453-F, U.S. Estate of Trust Income Tax Declaration and Signature for...

  2. Regional Concentration and Confidence Regions

    OpenAIRE

    Stepanyan, Andranik; von Auer, Ludwig; Trede, Mark

    2015-01-01

    Industries necessarily differ with respect to their type of geographical concentration. When some industries are overrepresented in urban areas (urban concentration), then some other industries must be overrepresented in rural areas (rural concentration). Unfortunately, the existing measures of concentration cannot distinguish between urban and rural concentration. They simply ignore the problem and rank industries with respect to their degree of concentration, even though these industries ma...

  3. Weird past tense forms.

    Science.gov (United States)

    Xu, F; Pinker, S

    1995-10-01

    It is often assumed that children go through a stage in which they systematically overapply irregular past tense patterns to inappropriate verbs, as in wipe-wope, bring-brang, trick-truck, walk-has walken. Such errors have been interpreted both as reflecting over-use of minor grammatical rules (e.g. 'change i to a'), and as reflecting the operation of a connectionist pattern associator network that superimposes and blends patterns of various degrees of generality. But the actual rate, time course, and nature of these errors have never been documented. We analysed 20,000 past tense and participle usages from nine children in the CHILDES database, looking for overapplications of irregular vowel-change patterns, as in brang, blends, as in branged, productive suffixations of -en, as in walken, gross distortions, as in mail-membled, and double-suffixation, as in walkeded. These errors were collectively quite rare; children made them in about two tenths of one per cent of the opportunities, and with few stable patterns: the errors were not predominantly word-substitutions, did not occur predominantly with irregular stems, showed no consistency across verbs or ages, and showed no clear age trend. Most (though not all) of the errors were based closely on existing irregular verbs; gross distortions never occurred. We suggest that both rule-theories and connectionist theories have tended to overestimate the predominance of such errors. Children master irregular forms quite accurately, presumably because irregular forms are just a special case of the arbitrary sound-meaning pairings that define words, and because children are good at learning words.

  4. Forming Spirals From Shadows

    Science.gov (United States)

    Kohler, Susanna

    2016-07-01

    What causes the large-scale spiral structures found in some protoplanetary disks? Most models assume theyre created by newly-forming planets, but a new study suggests that planets might have nothing to do with it.Perturbations from Planets?In some transition disks protoplanetary disks with gaps in their inner regions weve directly imaged large-scale spiral arms. Many theories currently attribute the formation of these structures to young planets: either the direct perturbations of a planet embedded in the disk cause the spirals, or theyre indirectly caused by the orbit of a planetary body outside of the arms.Another example of spiral arms detected in a protoplanetary disk, MWC 758. [NASA/ESA/ESO/M. Benisty et al.]But what if you could get spirals without any planets? A team of scientists led by Matas Montesinos (University of Chile) have recently published a study in which they examine what happens to a shadowed protoplanetary disk.Casting Shadows with WarpsIn the teams setup, they envision a protoplanetary disk that is warped: the inner region is slightly tilted relative to the outer region. As the central star casts light out over its protoplanetary disk, this disk warping would cause some regions of the disk to be shaded in a way that isnt axially symmetric with potentially interesting implications.Montesinos and collaborators ran 2D hydrodynamics simulations to determine what happens to the motion of particles within the disk when they pass in and out of the shadowed regions. Since the shadowed regions are significantly colder than the illuminated disk, the pressure in these regions is much lower. Particles are therefore accelerated and decelerated as they pass through these regions, and the lack of axial symmetry causes spiral density waves to form in the disk as a result.Initial profile for the stellar heating rate per unit area for one of the authors simulations. The regions shadowed as a result of the disk warp subtend 0.5 radians each (shown on the left

  5. 硫酸亚铁浓度对TA2纯钛微弧氧化膜层颜色的影响%Influence of FeSO4 concentration on color of films formed on titanium by micro-arc oxidation

    Institute of Scientific and Technical Information of China (English)

    唐辉; 于德珍; 王福平; 王云龙; 辛铁柱; 徐吉林

    2009-01-01

    A light brown ceramic coating with even color distributed and good compaction was obtained on TA2 pure titanium substrate by micro-arc oxidation in the Na3PO4 electrolyte system containing FeSO4.The influence of FeSO4 concentration on color of the micro-arc oxidation film was studied.The results show that the color of the oxide film is in the Chinese people tooth′s chromaticity distribution range,which has special application for the tetracyclin tooth or the fluorine spot tooth.With increasing concentration of ferrous sulfate in the electrolyte,the color of the oxide film changes toward red and yellow.%在以Na3PO4为主盐溶液的电解液体系中加入FeSO4,在纯钛TA2基体上进行微弧氧化,获得颜色均匀、致密性较好的浅棕色氧化物陶瓷膜层,研究了FeSO4浓度对微弧氧化膜层颜色的影响规律.结果表明,该膜层颜色在中国人牙齿颜色分布的色度范围内,对由四环素和氟引起的变色牙遮色有特殊应用,溶液中FeSO4浓度的增大,膜层的颜色向红色和黄色发生偏移.

  6. ANTISTAPHYLOCOCCAL ACTIVITY OF LIPOSOMAL FORMS OF LINCOMYCIN

    Directory of Open Access Journals (Sweden)

    Derkach SA

    2015-04-01

    Full Text Available Nowadays the vital problem of modern medicine is a tendency to emerging of both nosocomial and community-acquired strains before antibiotic resistance forming. The complexity of antibiotic therapy of diseases caused by methicillin resistant staphylococci having high poly resistance almost to every classes of antibacterial agents is of prime importance. One of the ways to improve antibacterial preparations still remains the development of their liposomal forms. This work studies antistaphylococcal activity (according to MIC of the liposomal form of lincomycin developed in the Institute of Dermatology and Venereology of Ukraine by Ivanova N. N., the Candidate of Сhemical Sciences.The purpose of this research work was to study liposomal inhibiting concentration of the liposomalny form of lincomycin and a commercial preparation lincomycin (produced by CJSC “Pharmaceutical firm "Darnitsa". Determination of the minimum inhibiting concentration was carried out by a tablet micromethod by consecutive cultivations of the samples under study.It is shown that MIC of liposomal lincomycin is eight times as low as usual lincomycin (0,23mkg/ml to 1,87 mkg/ml. Antibacterial activity of the liposomal form of lincomycin is studied concerning the patients selected from the different biotopes with pyo inflammatory diseases of staphylococcus strains (15 strains – methicillin sensitive, 12 strains - methicillin resistant.It is shown authentically the higher sensitivity of S. aureus strains to the liposomal form of lincomycin in comparison with usual lincomycin . Also 50.0% of MRSA strains were sensitive to the liposomalny form of lincomycin that shows the perspective for the development of the liposomal forms of antibiotics to cure staphylococcal infections.

  7. Concentration solar thermal power

    International Nuclear Information System (INIS)

    As the production of electricity by concentration solar power (CSP) installations is said to be a source of energy for the future, the author discusses past experiments (notably the French Thermis project), and the different techniques which are currently being used. He indicates the regions which appear to be the most appropriate for this technique. He presents the three main techniques: parabolic cylinder, tower, and Stirling cycle installations. He discusses the issue of intermittency. He proposes an assessment of prices and of their evolution, and indicates the investments made in different installations (in Italy, Spain, Germany and Portugal). He comments the case of hybrid installations (sun and gas), evokes the Desertec project proposed by the German industry which comprises a set of hybrid installations. He notices that there is no significant technological evolution for this process

  8. Group valued differential forms revisited

    DEFF Research Database (Denmark)

    Kock, Anders

    We study the relationship between combinatorial group valued differential forms, and classical differential forms with values in the corresponding Lie algebra. In particular, we compare simplicial coboundary and exterior derivative for 1-forms. The results represent strengthenings of results...

  9. Moon (Form-Origin)

    Science.gov (United States)

    Tsiapas, Elias

    2016-04-01

    When the Earth was formed, it was in a state of burning heat. As time went by, temperature on the planet's surface was falling due to radiation and heat transfer, and various components (crusts) began taking solid form at the Earth's poles. The formation of crusts took place at the Earth's poles, because the stirring of burning and fluid masses on the surface of the Earth was significantly slighter there than it was on the equator. Due to centrifugal force and Coriolis Effect, these solid masses headed towards the equator; those originating from the North Pole followed a south-western course, while those originating from the South Pole followed a north-western course and there they rotated from west to east at a lower speed than the underlying burning and liquid earth, because of their lower initial linear velocity, their solid state and inertia. Because inertia is proportional to mass, the initially larger solid body swept all new solid ones, incorporating them to its western side. The density of the new solid masses was higher, because the components on the surface would freeze and solidify first, before the underlying thicker components. As a result, the western side of the initial islet of solid rocks submerged, while the east side elevated. . As a result of the above, this initial islet began to spin in reverse, and after taking on the shape of a sphere, it formed the "heart" of the Moon. The Moon-sphere, rolling on the equator, would sink the solid rocks that continued to descend from the Earth's poles. The sinking rocks partially melted because of higher temperatures in the greater depths that the Moon descended to, while part of the rocks' mass bonded with the Moon and also served as a heat-insulating material, preventing the descended side of the sphere from melting. Combined with the Earth's liquid mass that covered its emerging eastern surface, new sphere-shaped shells were created, with increased density and very powerful structural cohesion. During the

  10. Pushing concentration of stationary solar concentrators to the limit.

    Science.gov (United States)

    Winston, Roland; Zhang, Weiya

    2010-04-26

    We give the theoretical limit of concentration allowed by nonimaging optics for stationary solar concentrators after reviewing sun- earth geometry in direction cosine space. We then discuss the design principles that we follow to approach the maximum concentration along with examples including a hollow CPC trough, a dielectric CPC trough, and a 3D dielectric stationary solar concentrator which concentrates sun light four times (4x), eight hours per day year around. PMID:20607887

  11. Do atmospheric aerosols form glasses?

    Directory of Open Access Journals (Sweden)

    D. A. Pedernera

    2008-09-01

    Full Text Available A new process is presented by which water soluble organics might influence ice nucleation, ice growth, chemical reactions and water uptake of aerosols in the upper troposphere: the formation of glassy aerosol particles. Glasses are disordered amorphous (non-crystalline solids that form when a liquid is cooled without crystallization until the viscosity increases exponentially and molecular diffusion practically ceases. The glass transition temperatures, Tg, homogeneous ice nucleation temperatures, Thom, and ice melting temperatures, Tm, of various aqueous inorganic, organic and multi-component solutions are investigated with a differential scanning calorimeter. The investigated solutes are: various polyols, glucose, raffinose, levoglucosan, an aromatic compound, sulfuric acid, ammonium bisulfate and mixtures of dicarboxylic acids (M5, of dicarboxylic acids and ammonium sulfate (M5AS, of two polyols, of glucose and ammonium nitrate, and of raffinose and M5AS. The results indicate that aqueous solutions of the investigated inorganic solutes show Tg values that are too low to be of atmospheric importance. In contrast, aqueous organic and multi-component solutions readily form glasses at low but atmospherically relevant temperatures (≤230 K. To apply the laboratory data to the atmospheric situation, the measured phase transition temperatures were transformed from a concentration to a water activity scale by extrapolating water activities determined between 252 K and 313 K to lower temperatures. The obtained state diagrams reveal that the higher the molar mass of the aqueous organic or multi-component solutes, the higher Tg of their respective solutions at a given water activity. To a lesser extent, Tg also depends on the hydrophilicity of the organic solutes. Therefore, aerosol particles containing larger (≳150 g mol−1 and

  12. New education coalition formed

    Science.gov (United States)

    Watt Ireto, M. Frank

    The Coalition for Earth Science Education (CESE) was recently formed to promote Earth science education at all levels. Earth science is a diverse group of sciences and as a result, professional and academic organizations from the various areas, though united in their goal to stimulate student enthusiasm for the Earth sciences, have not had an effective way of reaching students or their precollege teachers. Over the past year, meetings sponsored by the National Academy of Science's Board on Earth Sciences and Resources and the National Science Foundation have paved the way for this coalition. Victor Mayer, Director of the Program for Leadership in Earth Systems Science (PLESE) project at the University of Ohio, has been the leader in initiating and promoting this effort for the last several years.The purpose of CESE is to promote communication among the member organizations and to coordinate projects in Earth science education. Individual organizations will continue to develop and run projects, but will be able to find out what types of projects others are working on or have completed through a coalition clearinghouse. The clearinghouse should aid organizations as they design projects and should afford opportunities for collaborative efforts. This will directly benefit teachers, who will be able to contact one source for information on the multitude of projects in the Earth and space sciences. The new coalition's steering committee is working on goals and guidelines, and will give a report at the next coalition meeting at the National Science Teachers Association annual convention in Boston.

  13. Image forming apparatus

    DEFF Research Database (Denmark)

    2005-01-01

    An image H(x, y) for displaying a target image G(x, y) is displayed on a liquid-crystal display panel and illumination light from an illumination light source is made to pass therethrough to form an image on a PALSLM. Read light hv is radiated to the PALSLM and a phase-modulated light image alpha...... (x, y) read out of the PALSLM is subjected to Fourier transform by a lens. A phase contrast filter gives a predetermined phase shift to only the zero-order light component of Fourier light image alpha f(x, y). The phase-shifted light image is subjected to inverse Fourier transform by a lens...... to project an output image O(x, y) to an output plane. A light image O'(x, y) branched by a beam sampler is picked up by a pickup device and an evaluation value calculating unit evaluates conformity between the image O(x, y) and the image G(x, y).; A control unit performs feedback control of optical...

  14. Photovoltaic solar concentrator

    Energy Technology Data Exchange (ETDEWEB)

    Nielson, Gregory N.; Cruz-Campa, Jose Luis; Okandan, Murat; Resnick, Paul J.; Sanchez, Carlos Anthony; Clews, Peggy J.; Gupta, Vipin P.

    2015-09-08

    A process including forming a photovoltaic solar cell on a substrate, the photovoltaic solar cell comprising an anchor positioned between the photovoltaic solar cell and the substrate to suspend the photovoltaic solar cell from the substrate. A surface of the photovoltaic solar cell opposite the substrate is attached to a receiving substrate. The receiving substrate may be bonded to the photovoltaic solar cell using an adhesive force or a metal connecting member. The photovoltaic solar cell is then detached from the substrate by lifting the receiving substrate having the photovoltaic solar cell attached thereto and severing the anchor connecting the photovoltaic solar cell to the substrate. Depending upon the type of receiving substrate used, the photovoltaic solar cell may be removed from the receiving substrate or remain on the receiving substrate for use in the final product.

  15. Watching How Planets Form

    Science.gov (United States)

    2006-09-01

    Anatomy of a Planet-Forming Disc around a Star More Massive than the Sun With the VISIR instrument on ESO's Very Large Telescope, astronomers have mapped the disc around a star more massive than the Sun. The very extended and flared disc most likely contains enough gas and dust to spawn planets. It appears as a precursor of debris discs such as the one around Vega-like stars and thus provides the rare opportunity to witness the conditions prevailing prior to or during planet formation. "Planets form in massive, gaseous and dusty proto-planetary discs that surround nascent stars. This process must be rather ubiquitous as more than 200 planets have now been found around stars other than the Sun," said Pierre-Olivier Lagage, from CEA Saclay (France) and leader of the team that carried out the observations. "However, very little is known about these discs, especially those around stars more massive than the Sun. Such stars are much more luminous and could have a large influence on their disc, possibly quickly destroying the inner part." The astronomers used the VISIR instrument [1] on ESO's Very Large Telescope to map in the infrared the disc surrounding the young star HD 97048. With an age of a few million years [2], HD 97048 belongs to the Chameleon I dark cloud, a stellar nursery 600 light-years away. The star is 40 times more luminous than our Sun and is 2.5 times as massive. The astronomers could only have achieved such a detailed view due to the high angular resolution offered by an 8-metre size telescope in the infrared, reaching a resolution of 0.33 arcsecond. They discovered a very large disc, at least 12 times more extended than the orbit of the farthest planet in the Solar System, Neptune. The observations suggest the disc to be flared. "This is the first time such a structure, predicted by some theoretical models, is imaged around a massive star," said Lagage. ESO PR Photo 36/06 ESO PR Photo 36/06 A Flared Proto-Planetary Disc Such a geometry can only be

  16. Workplace concentration of immigrants.

    Science.gov (United States)

    Andersson, Fredrik; García-Pérez, Mónica; Haltiwanger, John; McCue, Kristin; Sanders, Seth

    2014-12-01

    Casual observation suggests that in most U.S. urban labor markets, immigrants have more immigrant coworkers than native-born workers do. While seeming obvious, this excess tendency to work together has not been precisely measured, nor have its sources been quantified. Using matched employer-employee data from the U.S. Census Bureau Longitudinal Employer-Household Dynamics (LEHD) database on a set of metropolitan statistical areas (MSAs) with substantial immigrant populations, we find that, on average, 37 % of an immigrant's coworkers are themselves immigrants; in contrast, only 14 % of a native-born worker's coworkers are immigrants. We decompose this difference into the probability of working with compatriots versus with immigrants from other source countries. Using human capital, employer, and location characteristics, we narrow the mechanisms that might explain immigrant concentration. We find that industry, language, and residential segregation collectively explain almost all the excess tendency to work with immigrants from other source countries, but they have limited power to explain work with compatriots. This large unexplained compatriot component suggests an important role for unmeasured country-specific factors, such as social networks. PMID:25425452

  17. Doing Focus-on-Form.

    Science.gov (United States)

    Ellis, Rod; Basturkmen, Helen; Loewen, Shawn

    2002-01-01

    Considers the rationale for using a focus on form approach to teaching form as opposed to the more traditional focus on forms approach where linguistic features are treated sequentially. Describes methodological options for attending to form in communication. (Author/VWL)

  18. Measurement of Odour Concentration from Livestock Farm

    OpenAIRE

    Lukman Ismail; Zaini Sakawi; Mohamad Khalil Saipi

    2014-01-01

    Odourpollution originated from livestock farms is a form of harmful air pollution.Odour pollution causes health issues to the surrounding local communities. Yet, odour pollution issues have not been given deserving attention by the relevant authorities and the Malaysian public. To raise the awareness, this study highlights a case of odour pollution generated from cattle and buffalo farms in Bandar Baru Bangi, Selangor.Odour measurement was taken using an instrument called Concentration Meter ...

  19. The characteristics of novel dosage forms

    Directory of Open Access Journals (Sweden)

    Milić-Aškrabić Jela

    2003-01-01

    Full Text Available The objective of pharmaceutical-technological development is to find a procedure of transforming an active substance (a drug into a drug dosage form which is not only acceptable for application, but also enables the active substance to be released following administration, pursuant to therapy objectives. The aim is that the concentration of the active substance in the action location rapidly reaches a therapeutic level and maintains an approximately constant level in the course of a particular time, according to the established therapeutic goal. The primary objective is to present the active ingredient (drug in the form and concentration/quantity that enables the corresponding therapeutic response, i.e. to control the site and rate of medicinal substance release from the drug, as well as the rate at which it reaches the membranes and surfaces to which it is absorbed, while applying a common method of administration. The procedures used to achieve this goal are becoming highly complex and demanding and are aiming at sophisticated drug delivery systems and functional packaging material. Development from the existing drug molecule, through the conventional drug dosage form, to a new system of drug "delivery" (novel delivery system, can improve the drug (active substance characteristics significantly in view of compliance (acceptability by the patient, safety and efficiency. The paper presents an overview of the most important examples of pharmaceutical forms with controlled release and advanced drug "carriers".

  20. A statistical proxy for sulphuric acid concentration

    Directory of Open Access Journals (Sweden)

    S. Mikkonen

    2011-07-01

    Full Text Available Gaseous sulphuric acid is a key precursor for new particle formation in the atmosphere. Previous experimental studies have confirmed a strong correlation between the number concentrations of freshly formed particles and the ambient concentrations of sulphuric acid. This study evaluates a body of experimental gas phase sulphuric acid concentrations, as measured by Chemical Ionization Mass Spectrometry (CIMS during six intensive measurement campaigns and one long-term observational period. The campaign datasets were measured in Hyytiälä, Finland, in 2003 and 2007, in San Pietro Capofiume, Italy, in 2009, in Melpitz, Germany, in 2008, in Atlanta, Georgia, USA, in 2002, and in Niwot Ridge, Colorado, USA, in 2007. The long term data were obtained in Hohenpeissenberg, Germany, during 1998 to 2000. The measured time series were used to construct proximity measures ("proxies" for sulphuric acid concentration by using statistical analysis methods. The objective of this study is to find a proxy for sulfuric acid that is valid in as many different atmospheric environments as possible. Our most accurate and universal formulation of the sulphuric acid concentration proxy uses global solar radiation, SO2 concentration, condensation sink and relative humidity as predictor variables, yielding a correlation measure (R of 0.87 between observed concentration and the proxy predictions. Interestingly, the role of the condensation sink in the proxy was only minor, since similarly accurate proxies could be constructed with global solar radiation and SO2 concentration alone. This could be attributed to SO2 being an indicator for anthropogenic pollution, including particulate and gaseous emissions which represent sinks for the OH radical that, in turn, is needed for the formation of sulphuric acid.

  1. A statistical proxy for sulphuric acid concentration

    Directory of Open Access Journals (Sweden)

    S. Mikkonen

    2011-11-01

    Full Text Available Gaseous sulphuric acid is a key precursor for new particle formation in the atmosphere. Previous experimental studies have confirmed a strong correlation between the number concentrations of freshly formed particles and the ambient concentrations of sulphuric acid. This study evaluates a body of experimental gas phase sulphuric acid concentrations, as measured by Chemical Ionization Mass Spectrometry (CIMS during six intensive measurement campaigns and one long-term observational period. The campaign datasets were measured in Hyytiälä, Finland, in 2003 and 2007, in San Pietro Capofiume, Italy, in 2009, in Melpitz, Germany, in 2008, in Atlanta, Georgia, USA, in 2002, and in Niwot Ridge, Colorado, USA, in 2007. The long term data were obtained in Hohenpeissenberg, Germany, during 1998 to 2000. The measured time series were used to construct proximity measures ("proxies" for sulphuric acid concentration by using statistical analysis methods. The objective of this study is to find a proxy for sulfuric acid that is valid in as many different atmospheric environments as possible. Our most accurate and universal formulation of the sulphuric acid concentration proxy uses global solar radiation, SO2 concentration, condensation sink and relative humidity as predictor variables, yielding a correlation measure (R of 0.87 between observed concentration and the proxy predictions. Interestingly, the role of the condensation sink in the proxy was only minor, since similarly accurate proxies could be constructed with global solar radiation and SO2 concentration alone. This could be attributed to SO2 being an indicator for anthropogenic pollution, including particulate and gaseous emissions which represent sinks for the OH radical that, in turn, is needed for the formation of sulphuric acid.

  2. Geographic Concentration in China's Manufacturing

    Institute of Scientific and Technical Information of China (English)

    Zhang Tongsheng; Gan Guohui

    2006-01-01

    This paper empirically examines variations and changes in manufacturing concentration and their determinants in China over the 1980-2003period with a sample of 26 industries. The analysis indicates that average industrial concentration has increased during the 1990s. Studies show that scale economies and industry policies are important determinants for industries geographical concentration; factor endowments and the location of foreign direct investment are also found to have a positive effect on concentration.

  3. Advances in metal forming expert system for metal forming

    CERN Document Server

    Hingole, Rahulkumar Shivajirao

    2015-01-01

    This comprehensive book offers a clear account of the theory and applications of advanced metal forming. It provides a detailed discussion of specific forming processes, such as deep drawing, rolling, bending extrusion and stamping. The author highlights recent developments of metal forming technologies and explains sound, new and powerful expert system techniques for solving advanced engineering problems in metal forming. In addition, the basics of expert systems, their importance and applications to metal forming processes, computer-aided analysis of metalworking processes, formability analysis, mathematical modeling and case studies of individual processes are presented.

  4. Bronchial secretion concentrations of tobramycin.

    Science.gov (United States)

    Alexander, M R; Schoell, J; Hicklin, G; Kasik, J E; Coleman, D

    1982-02-01

    The mean concentrations of tobramycin in bronchial secretions from patients with pneumonia were almost two times greater than secretions from patients free of lung infection. Mean tobramycin bronchial secretion to serum concentration ratios also were higher when obtained from infected lungs (0.66 versus 0.17) These data suggest that lung infection enhances the concentrations of tobramycin in bronchial secretions. PMID:7065524

  5. Scaling of Hadronic Form Factors in Point Form Kinematics

    CERN Document Server

    Coester, F

    2003-01-01

    The general features of baryon form factors calculated with point form kinematics are derived. With point form kinematics and spectator currents hadronic form factors are functions of $\\eta:={1\\over 4}(v_{out}-v_{in})^2$ and, over a range of $\\eta$ values are insensitive to unitary scale transformations of the model wave functions when the extent of the wave function is small compared to the scale defined by the constituent mass, $ \\ll 1/m^2$. The form factors are sensitive to the shape of such compact wave functions. Simple 3-quark proton wave functions are employed to illustrate these features. Rational and algebraic model wave functions lead to a reasonable representation of the empirical form factors, while Gaussian wave functions fail. For large values of $\\eta$ point form kinematics with spectator currents leads to power law behavior of the wave functions.

  6. Visual perception of tree forms

    Energy Technology Data Exchange (ETDEWEB)

    Muederrisoglu, Haldun; Eroglu, Engin; OEzkan, Suekran; Ak, Kivanc [Department of Landscape Architecture, Faculty of Forestry, Abant Izzet Baysal University, 81000, Duzce (Turkey)

    2006-06-15

    This study, made in the cities of Adapazari, Duzce, and Bolu, has three fundamental goals. The first one is the evaluation of visual quality and strength of each tree form, second is the determination of visual quality and strength of different tree forms next to each other, and the third goal of this study is determining the effects of personal characteristics to the perception of tree forms. To reach these three goals the semantic differential method was used to evaluate graphical visions of tree forms. According to the findings, trees with pyramid forms have the most effective visual quality and strength. Pyramid-formed tree combinations have higher visual quality and strength than mixed combinations do. At the same time personal characteristics are effective on the visual perception of tree forms. A strong relationship between the amount of area per person in the cities the participants live in and their visual perception of tree forms has been found. (author)

  7. The statistics of LCDM Halo Concentrations

    CERN Document Server

    Neto, Angelo F; Bett, Philip; Cole, Shaun; Navarro, Julio F; Frenk, Carlos S; White, Simon D M; Springel, Volker; Jenkins, Adrian

    2007-01-01

    We use the Millennium Simulation (MS) to study the statistics of LCDM halo concentrations at z = 0. Our results confirm that the average halo concentration declines monotonically with mass; a power-law fits well the concentration-mass relation for over 3 decades in mass, up to the most massive objects to form in a LCDM universe (~ 10^15 h^-1 Msol). This is in clear disagreement with the predictions of the model proposed by Bullock et al. for these rare objects, and agrees better with the original predictions of Navarro, Frenk, & White. The large volume surveyed, together with the unprecedented numerical resolution of the MS, allow us to estimate with confidence the distribution of concentrations and, consequently, the abundance of systems with unusual properties. About one in a hundred cluster haloes (M200 >~ 3x10^14 h^-1 Msol) have concentrations exceeding c200 = 7.5, a result that may be used to interpret the likelihood of unusually strong massive gravitational lenses, such as Abell 1689, in the LCDM co...

  8. ParFORM: Recent development

    International Nuclear Information System (INIS)

    We report on the status of our project of parallelization of the symbolic manipulation program FORM. We have now parallel versions of FORM running on Cluster- or SMP-architecture. These versions can be used to run arbitrary FORM programs in parallel

  9. Investigating Form-Focused Instruction.

    Science.gov (United States)

    Ellis, Rod

    2001-01-01

    Provides an historical sketch of form-focused instruction research, defines what is meant by form-focused instruction, and discusses the main research methods that have been used to investigate form-focused instruction in terms of a broad distinction between confirmatory and interpretive research. (Author/VWL)

  10. ParFORM: recent development

    OpenAIRE

    Tentyukov, M.; Vermaseren, J. A. M.; Staudenmaier, H. M.

    2005-01-01

    We report on the status of our project of parallelization of the symbolic manipulation program FORM. We have now parallel versions of FORM running on Cluster- or SMP-architectures. These versions can be used to run arbitrary FORM programs in parallel.

  11. FormLink/FeynCalcFormLink : Embedding FORM in Mathematica and FeynCalc

    CERN Document Server

    Feng, Feng

    2012-01-01

    FORM, a symbolic manipulation system, has been widely used in a lot of calculations for High Energy Physics due to its high performance and fficient design. Mathematica, another computational software program, has also widely been used, but more for reasons of generality and user-friendliness than for speed. Especially calculations involving tensors and noncommutative operations like calculating Dirac traces can be rather slow in Mathematica, compared to FORM. In this article we describe FormLink and FeynCalcFormLink, two Mathematica packages to link Mathematica and FeynCalc with FORM. FormLink can be used without FeynCalc and FeynCalcFormLink, which is an extension loading FormLink and FeynCalc automatically. With these two packages the impressive speed and other special features of FORM get embedded into the generality of Mathematica and FeynCalc in a simple manner. FeynCalcFormLink provides a FORM-based turbo for FeynCalc, making it much more efficient. FormLink turns Mathematica into an editor and code or...

  12. Optical assessment of nonimaging concentrators.

    Science.gov (United States)

    Timinger, A; Kribus, A; Ries, H; Smith, T; Walther, M

    2000-11-01

    An optical measurement method for nonimaging radiation concentrators is proposed. A Lambertian light source is placed in the exit aperture of the concentrator. Looking into the concentrator's entrance aperture from a remote position, one can photograph the transmission patterns. The patterns show the transmission of radiation through the concentrator with the full resolution of the four-dimensional phase space of geometric optics. By matching ray-tracing simulations to the measurement, one can achieve detailed and accurate information about the geometry of the concentrator. This is a remote, noncontact measurement and can be performed in situ for installed concentrators. Additional information regarding small-scale reflector waviness and surface reflectivity can also be obtained from the same measurement with additional analysis. PMID:18354564

  13. A Nonlinear Regression Model Estimating Single Source Concentrations of Primary and Secondarily Formed 2.5

    Science.gov (United States)

    Various approaches and tools exist to estimate local and regional PM2.5 impacts from a single emissions source, ranging from simple screening techniques to Gaussian based dispersion models and complex grid-based Eulerian photochemical transport models. These approache...

  14. Discourse of the form and concentration of surfactants to ensure the sustainability foam-emulsive products

    Directory of Open Access Journals (Sweden)

    Oleg

    2015-05-01

    Full Text Available Introduction. Development of dry mixes for making spumy and emulsion products are topical, because nowadays there is a tendency to minimize the time spent on the process of cooking, which is achieved by the use of semi finished products high degree of readiness. Materials and methods. Foaming ability was determined by the method of multiplicity of the foam, the stability of unstable foam-by the half-life method of foam, highly resistant foam - as a ratio of the height of the column of foam after exposure for 24 hours. Results. Was determined the influence of sunflower oil on the foaming ability and half-life foam of systems «sodium caseinate-oil». It was found that getting systems with high index of foaming capacity and foam stability in the presence of oil in the system is impossible without the use of low molecular weight surfactants. Substantiated recommendations regarding the feasibility of using two surfactants in systems «sodium caseinate-surfactants-oil», which provide the necessary kinship surfaces air, fat and water phases. it has been found that the use of 2,5...3,5% mono-and diglycerides of fatty acid sand Lecithin’s 0.15...0.25% in the content of sodium caseinate about 0.5% allows to receive the stable foam-emulsive systems containing sunflower oil 7...8% and foaming ability about 640±1%. Conclusions. It is established that for ensuring high indicators foaming capacity and stability of foam-emulsive systems required the use of low-molecular surfactants. The research results, is recommended to use when developing technology of foam-emulsive products.

  15. Discourse of the form and concentration of surfactants to ensure the sustainability foam-emulsive products

    Directory of Open Access Journals (Sweden)

    O. Kotlyar

    2015-05-01

    Full Text Available Introduction. Development of dry mixes for making spumy and emulsion products are topical, because nowadays there is a tendency to minimize the time spent on the process of cooking, which is achieved by the use of semi finished products high degree of readiness. Materials and methods. Foaming ability was determined by the method of multiplicity of the foam, the stability of unstable foam-by the half-life method of foam, highly resistant foam - as a ratio of the height of the column of foam after exposure for 24 hours. Results. Was determined the influence of sunflower oil on the foaming ability and half-life foam of systems «sodium caseinate-oil». It was found that getting systems with high index of foaming capacity and foam stability in the presence of oil in the system is impossible without the use of low molecular weight surfactants. Substantiated recommendations regarding the feasibility of using two surfactants in systems «sodium caseinate-surfactants-oil», which provide the necessary kinship surfaces air, fat and water phases. it has been found that the use of 2,5...3,5% mono-and diglycerides of fatty acid sand Lecithin’s 0.15...0.25% in the content of sodium caseinate about 0.5% allows to receive the stable foam-emulsive systems containing sunflower oil 7...8% and foaming ability about 640±1%. Conclusions. It is established that for ensuring high indicators foaming capacity and stability of foam-emulsive systems required the use of low-molecular surfactants. The research results, is recommended to use when developing technology of foam-emulsive products. Introduction

  16. SEMISOLID DOSAGE FORM OF PHENYTOIN SODIUM

    Directory of Open Access Journals (Sweden)

    Maiada M Almousilly

    2012-11-01

    Full Text Available Phenytoin sodium was formulated in a solid dosage form using different bases; o/w emulsion base, water soluble base, oleaginous base, and vanishing cream base. Bases were prepared in two different concentrations, 5% and 10% w/w. The diffusion of the drug from each of the above bases was investigated. Results indicated that the effect of the type of ointment base on the release rate of phenytoin sodium is significant. The rate and extent of phenytoin sodium release and diffusion through mouse skin was higher from the water soluble base (10% w/w compared to other ointment bases, the difference was highly significant (P< 0.05.

  17. SEMISOLID DOSAGE FORM OF PHENYTOIN SODIUM

    OpenAIRE

    Maiada M Almousilly; Loay K. Abdulrahman; Sadiq H. Alshmesawy; Fatima A. Tawfiq

    2012-01-01

    Phenytoin sodium was formulated in a solid dosage form using different bases; o/w emulsion base, water soluble base, oleaginous base, and vanishing cream base. Bases were prepared in two different concentrations, 5% and 10% w/w. The diffusion of the drug from each of the above bases was investigated. Results indicated that the effect of the type of ointment base on the release rate of phenytoin sodium is significant. The rate and extent of phenytoin sodium release and diffusion through mouse ...

  18. Discussion on Form Focused Instruction

    Institute of Scientific and Technical Information of China (English)

    冯滢

    2007-01-01

    The pedagogy of language teaching has moved from one extreme-Grammar Translation Method to the other-Communicative Language Teaching.Today Form Focused Instruction(FFI)has emerged,intending to bring language forms instructionback to the communicative language classroom.Despite of the approval of this new approach,there is a hot dispute on its two types of application:Focus on Form or Focus on FormS.This article briefly analyzes FFI in recent research studies with focus on the choice between the two types of application.The tentative conclusion is FFI does show some explicit and reliable effects on accuracy and error elimination in language teaching;however,the investigation into its application is not simply either Focus on Form Or Focus on FormS,but focuses on the optimal combination of the two in teaching.

  19. Temporal form in interaction design

    DEFF Research Database (Denmark)

    Vallgårda, Anna; Winther, Morten Trøstrup; Mørch, Nina;

    2015-01-01

    Interaction design is distinguished from most other design disciplines through its temporal form. Temporal form is the computational structure that enables and demands a temporal expression in the resulting design. Temporal form is what enables poetry. In music, temporal form is the composition...... of tones, pauses, and timbre arranged into harmonies and rhythms. In interaction design it is, for instance, the behaviors of pixels on a screen or the movements in shape-changing interfaces. In this paper we show the power of working explicitly with temporal form in designing computational things. We give...... temporal forms by letting a series of expert designers reflect upon them. We borrow a framework from Boorstin’s film theory in which he distinguishes between the voyeuristic, the vicarious, and the visceral experience. We show how to use rhythms, complexity, gentle or forceful behavior, etc., to create...

  20. The semantics of biological forms.

    Science.gov (United States)

    Albertazzi, Liliana; Canal, Luisa; Dadam, James; Micciolo, Rocco

    2014-01-01

    This study analyses how certain qualitative perceptual appearances of biological forms are correlated with expressions of natural language. Making use of the Osgood semantic differential, we presented the subjects with 32 drawings of biological forms and a list of 10 pairs of connotative adjectives to be put in correlations with them merely by subjective judgments. The principal components analysis made it possible to group the semantics of forms according to two distinct axes of variability: harmony and dynamicity. Specifically, the nonspiculed, nonholed, and flat forms were perceived as harmonic and static; the rounded ones were harmonic and dynamic. The elongated forms were somewhat disharmonious and somewhat static. The results suggest the existence in the general population of a correspondence between perceptual and semantic processes, and of a nonsymbolic relation between visual forms and their adjectival expressions in natural language.

  1. Isometric Spacelike Immersions of Space Forms in Indefinite Space Forms

    Institute of Scientific and Technical Information of China (English)

    李海中; 吴岚

    2001-01-01

    Let M be a connected n-dimensional space form spacelike isometrically immersed in a (2n -1)-dimensional indefinite space form. If M is maximal, we prove that either M is totally geodesic or M is apiece of the n-dimensional hyperbolic cylinder in the (2n - 1)-dimensional pseudo-hyperbolic space.``

  2. Ideal 3D asymmetric concentrator

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Botella, Angel [Departamento Fisica Aplicada a los Recursos Naturales, Universidad Politecnica de Madrid, E.T.S.I. de Montes, Ciudad Universitaria s/n, 28040 Madrid (Spain); Fernandez-Balbuena, Antonio Alvarez; Vazquez, Daniel; Bernabeu, Eusebio [Departamento de Optica, Universidad Complutense de Madrid, Fac. CC. Fisicas, Ciudad Universitaria s/n, 28040 Madrid (Spain)

    2009-01-15

    Nonimaging optics is a field devoted to the design of optical components for applications such as solar concentration or illumination. In this field, many different techniques have been used for producing reflective and refractive optical devices, including reverse engineering techniques. In this paper we apply photometric field theory and elliptic ray bundles method to study 3D asymmetric - without rotational or translational symmetry - concentrators, which can be useful components for nontracking solar applications. We study the one-sheet hyperbolic concentrator and we demonstrate its behaviour as ideal 3D asymmetric concentrator. (author)

  3. Associations between urban form and cycling

    DEFF Research Database (Denmark)

    Nielsen, Thomas Alexander Sick; Olafsson, Anton Stahl; Carstensen, Trine Agervig

    The bikeability project has analysed the environmental correlates of cycling based on Danish National Transportation Survey data transportation and urban form micro-data; and based on a smaller sample of primary data which included housing preferences, policy and attitude variables. Analysis...... of National Travel Survey data indicated that established walkability factors such as density, connectivity and diversity are related to cycling, and that access to retail concentrations/centres, public transportation level-of-service, as well as competition between walking and cycling depending...... on environmental features can be added to the set of influential environmental factors. Attractive conditions for using public transportation or walking are related to less cycling. Highly relevant in the context of the promotion of cycling, the results suggest different effects of urban form on the probability...

  4. Forming Planetesimals in Solar and Extrasolar Nebulae

    CERN Document Server

    Chiang, E

    2009-01-01

    Planets are built from planetesimals: solids larger than a kilometer which grow by colliding pairwise. Planetesimals themselves are unlikely to form by two-body collisions; sub-km objects have gravitational fields individually too weak, and electrostatic attraction is too feeble for growth beyond a few cm. We review the possibility that planetesimals form when self-gravity brings together vast ensembles of small particles. Even when self-gravity is weak, aerodynamic processes can accumulate solids relative to gas, paving the way for gravitational collapse. Particles pile up as they drift radially inward. Gas turbulence stirs particles, but can also seed collapse by clumping them. While the feedback of solids on gas triggers vertical shear instabilities that obstruct self-gravity, this same feedback triggers streaming instabilities that strongly concentrate particles. Numerical simulations find that solids 10-100 cm in size gravitationally collapse in turbulent disks. We outline areas for progress, including t...

  5. Supergravity Actions with Integral Forms

    OpenAIRE

    Castellani, L.; Catenacci, R.; Grassi, P. A.

    2014-01-01

    Integral forms provide a natural and powerful tool for the construction of supergravity actions. They are generalizations of usual differential forms and are needed for a consistent theory of integration on supermanifolds. The group geometrical approach to supergravity and its variational principle are reformulated and clarified in this language. Central in our analysis is the Poincare' dual of a bosonic manifold embedded into a supermanifold. Finally, using integral forms we provide a proof ...

  6. Laser forming and welding processes

    CERN Document Server

    Yilbas, Bekir Sami; Shuja, Shahzada Zaman

    2013-01-01

    This book introduces model studies and experimental results associated with laser forming and welding such as laser induced bending, welding of sheet metals, and related practical applications. The book provides insight into the physical processes involved with laser forming and welding. The analytical study covers the formulation of laser induced bending while the model study demonstrates the simulation of bending and welding processes using the finite element method. Analytical and numerical solutions for laser forming and welding problems are provided.

  7. OZONE CONCENTRATION ATTRIBUTABLE PREMATURE DEATH IN POLAND

    Directory of Open Access Journals (Sweden)

    Krzysztof Skotak

    2010-03-01

    Full Text Available Ozone in the lower part of the atmosphere (troposphere, strong photochemical oxidant, is not directly emitted to the atmosphere but formed through a series of complex reactions. Ozone concentrations depends on ozone precursors air contamination (mainly nitrogen dioxide and non-methane volatile organic compounds and meteorological conditions (temperature and solar radiation. The main sectors emitted ozone precursors are road transport, power and heat generation plants, household (heating, industry, and petrol storage and distribution. Ozone and some of its precursors are also transported long distances in the atmosphere and are therefore considered a transboundary problem. As a result, the ozone concentrations are often low in busy urban areas and higher in suburban and rural areas. Nowadays, instead of particulate matter, ozone is one of the most widespread global air pollution problems. In and around urban areas, relatively large gradients of ozone can be observed. Because of its high reactivity in elevated concentrations ozone causes serious health problems and damage to ecosystems, agricultural crops and materials. Main ill-health endpoints as a results of ozone concentrations can be characterised as an effect of pulmonary and cardiovascular system, time morbidity and mortality series, development of atherosclerosis and asthma and finally reduction in life expectancy. The associations with increased daily mortality due to ozone concentrations are confirmed by many researches and epidemiological studies. Estimation of the level selected ill-health endpoints (mortality in total and due to cardiovascular and respiratory causes as a result of the short-term ozone exposure in Poland was the main aim of the project. Final results have been done based on estimation method elaborated by WHO, ozone measurements from National Air Quality Monitoring System and statistical information such as mortality rate and populations. All analysis have been done in

  8. A compiler for variational forms

    CERN Document Server

    Kirby, Robert C; 10.1145/1163641.1163644

    2011-01-01

    As a key step towards a complete automation of the finite element method, we present a new algorithm for automatic and efficient evaluation of multilinear variational forms. The algorithm has been implemented in the form of a compiler, the FEniCS Form Compiler FFC. We present benchmark results for a series of standard variational forms, including the incompressible Navier-Stokes equations and linear elasticity. The speedup compared to the standard quadrature-based approach is impressive; in some cases the speedup is as large as a factor 1000.

  9. Discussion on Form Focused Instruction

    Institute of Scientific and Technical Information of China (English)

    冯滢

    2007-01-01

    The pedagogy of language teaching has moved from one extreme-Grammar Translation Method to the other-Communicative Language Teaching.Today Form Focused Instruction(FFI) has emerged,intending to bring language forms instruction back to the communicative language classroom.Despite of the approval of this new approach,there is a hot dispute on its two types of application:Focus on Form or Focus on FormS.This article briefly analyzes FFI in recent research studies with focus on the choice between the two types ...

  10. INFORMATIONAL EFFECT OF A FORM

    Directory of Open Access Journals (Sweden)

    Kovalenko V.F.

    2016-02-01

    Full Text Available The study was conducted by method of light scattering of laser emission. The influence of the form field, mutual influence of mental informational and form torsional fields as well as the following exposure of water samples in the form field after the cease of informational influence on water structure were examined. Paper forms of a pyramid, a cylinder, and a prism were used. The experimental findings show that mechanism of mutual influence on water structure of the form and informational torsional fields depended on the initial conditions of spin restructuring process – the configuration of a form, the type of the form field (internal and external ones, and the initial water structure. The influence of the form field on informational aftereffect was determined, the character of which was defined by ratio of intensities of torsional form field and an informational soliton. The phenomenon of the abnormally large amplification of the informational aftereffect in the internal field of a pyramid demonstrating the attributes of positive reverse connection between the informational soliton and torsional field of water structure and selection of generated cluster sizes were discovered.

  11. Tectonics: The meaning of form

    DEFF Research Database (Denmark)

    Christiansen, Karl; Brandt, Per Aage

    Tectonics – The meaning of form deals with one of the core topics of architecture: the relationship between form and content. In the world of architecture, form is not only made from brick, glass and wood. Form means something. When a material is processed with sufficient technical skill...... perspectives. You can read the chapters in any order you like – from the beginning, end or the middle. There is no correct order. The project is methodologically inductive: the more essays you read, the broader your knowledge of tectonics get....

  12. Magnetic flux concentrations from turbulent stratified convection

    CERN Document Server

    Käpylä, P J; Kleeorin, N; Käpylä, M J; Rogachevskii, I

    2015-01-01

    (abridged) Context: The mechanisms that cause the formation of sunspots are still unclear. Aims: We study the self-organisation of initially uniform sub-equipartition magnetic fields by highly stratified turbulent convection. Methods: We perform simulations of magnetoconvection in Cartesian domains that are $8.5$-$24$ Mm deep and $34$-$96$ Mm wide. We impose either a vertical or a horizontal uniform magnetic field in a convection-driven turbulent flow. Results: We find that super-equipartition magnetic flux concentrations are formed near the surface with domain depths of $12.5$ and $24$ Mm. The size of the concentrations increases as the box size increases and the largest structures ($20$ Mm horizontally) are obtained in the 24 Mm deep models. The field strength in the concentrations is in the range of $3$-$5$ kG. The concentrations grow approximately linearly in time. The effective magnetic pressure measured in the simulations is positive near the surface and negative in the bulk of the convection zone. Its ...

  13. Critical Concentration Ratio for Solar Thermoelectric Generators

    Science.gov (United States)

    ur Rehman, Naveed; Siddiqui, Mubashir Ali

    2016-10-01

    A correlation for determining the critical concentration ratio (CCR) of solar concentrated thermoelectric generators (SCTEGs) has been established, and the significance of the contributing parameters is discussed in detail. For any SCTEG, higher concentration ratio leads to higher temperatures at the hot side of modules. However, the maximum value of this temperature for safe operation is limited by the material properties of the modules and should be considered as an important design constraint. Taking into account this limitation, the CCR can be defined as the maximum concentration ratio usable for a particular SCTEG. The established correlation is based on factors associated with the material and geometric properties of modules, thermal characteristics of the receiver, installation site attributes, and thermal and electrical operating conditions. To reduce the number of terms in the correlation, these factors are combined to form dimensionless groups by applying the Buckingham Pi theorem. A correlation model containing these groups is proposed and fit to a dataset obtained by simulating a thermodynamic (physical) model over sampled values acquired by applying the Latin hypercube sampling (LHS) technique over a realistic distribution of factors. The coefficient of determination and relative error are found to be 97% and ±20%, respectively. The correlation is validated by comparing the predicted results with literature values. In addition, the significance and effects of the Pi groups on the CCR are evaluated and thoroughly discussed. This study will lead to a wide range of opportunities regarding design and optimization of SCTEGs.

  14. Improving the forming capability of laser dynamic forming by using rubber as a forming medium

    Science.gov (United States)

    Shen, Zongbao; Liu, Huixia; Wang, Xiao; Wang, Cuntang

    2016-04-01

    Laser dynamic forming (LDF) is a novel high velocity forming technique, which employs laser-generated shock wave to load the sample. The forming velocity induced by the high energy laser pulse may exceed the critical forming velocity, resulting in the occurrence of premature fracture. To avoid the above premature fracture, rubber is introduced in LDF as a forming medium to prolong the loading duration in this paper. Laser induced shock wave energy is transferred to the sample in different forming stages, so the forming velocity can be kept below the critical forming velocity when the initial laser energy is high for fracture. Bulge forming experiments with and without rubber were performed to study the effect of rubber on loading duration. The experimental results show that, the shock wave energy attenuates during the propagation through the rubber layer, the rubber can avoid the premature fracture. So the plastic deformation can continue, the forming capability of LDF is improved. Due to the severe plastic deformation under rubber compression, adiabatic shear bands (ASB) occur in LDF with rubber. The material softening in ASB leads to the irregular fracture, which is different from the premature fracture pattern (regular fracture) in LDF without rubber. To better understand this deformation behavior, Johnson-Cook model is used to simulate the dynamic response and the evolution of ASB of copper sample. The simulation results also indicate the rubber can prolong the loading duration.

  15. School concentration and school travel

    NARCIS (Netherlands)

    De Boer, E.

    2010-01-01

    The purpose of the research as described in this Doctor’s thesis is twofold. Firstly it is to define in how far Dutch facilities for primary and secondary education were subjected to spatial concentration during recent decades. Secondly it is intended to assess what this concentration implied for th

  16. How to form asteroids from mm-sized grains

    CERN Document Server

    Carrera, Daniel; Davies, Melvyn B

    2016-01-01

    The size distribution of asteroids in the solar system suggests that they formed top-down, with 100-1000 km bodies forming from the gravitational collapse of dense clumps of small solid particles. We investigate the conditions under which solid particles can form dense clumps in a protoplanetary disc. We used a hydrodynamic code to model the solid-gas interaction in disc. We found that particles down to millimeter size can form dense clumps, but only in regions where solids make $\\sim$ 8% of the local surface density. More generally, we mapped the range of particle sizes and concentrations that is consistent with the formation of particle clumps.

  17. Ideal flux field dielectric concentrators.

    Science.gov (United States)

    García-Botella, Angel

    2011-10-01

    The concept of the vector flux field was first introduced as a photometrical theory and later developed in the field of nonimaging optics; it has provided new perspectives in the design of concentrators, overcoming standard ray tracing techniques. The flux field method has shown that reflective concentrators with the geometry of the field lines achieve the theoretical limit of concentration. In this paper we study the role of surfaces orthogonal to the field vector J. For rotationally symmetric systems J is orthogonal to its curl, and then a family of surfaces orthogonal to the lines of J exists, which can be called the family of surfaces of constant pseudopotential. Using the concept of the flux tube, it is possible to demonstrate that refractive concentrators with the shape of these pseudopotential surfaces achieve the theoretical limit of concentration. PMID:22016201

  18. Flame Propagation Through Concentration Gradient

    Institute of Scientific and Technical Information of China (English)

    JunyaIINO; MitsuakiTANABE; 等

    2000-01-01

    The experiment was carried out in homogeneous propane-air mixture and in several concentration gradient of mixture.Igniter is put on the upper side of the combustion chamber,In concentration gradient experiment.ixture was ignited from lean side.An experimental study was conducted in a combustion chamber.The combustion chamber has glass windows for optical measurements at any side.For the measurement of distribution of fuel concentration,infraed absorption method using 3.39μm He-Ne laser was used,and for the observation of proagating flams,Schlieren method was employed.As a measurment result of flame propagation velocity and flammable limit,for a mixture of an identical local equivalence ratio.flame propagation velocity in concentration gradient is faster than that in homogeneous mixture,and rich flammable limit in concentration gradient shows a tendency to be higher than that in homogeneous mixture.

  19. Higher-order Maass forms

    NARCIS (Netherlands)

    Bruggeman, R.W.; Diamantis, N.

    2012-01-01

    The spaces of Maass forms of even weight and of arbitrary order are studied. It is shown that, if we allow exponential growth at the cusps, these spaces are as large as algebraic restrictions allow. These results also apply to higher-order holomorphic forms of even weight.

  20. Automated Test-Form Generation

    Science.gov (United States)

    van der Linden, Wim J.; Diao, Qi

    2011-01-01

    In automated test assembly (ATA), the methodology of mixed-integer programming is used to select test items from an item bank to meet the specifications for a desired test form and optimize its measurement accuracy. The same methodology can be used to automate the formatting of the set of selected items into the actual test form. Three different…

  1. Identities between Modular Graph Forms

    CERN Document Server

    D'Hoker, Eric

    2016-01-01

    This paper investigates the relations between modular graph forms, which are generalizations of the modular graph functions that were introduced in earlier papers motivated by the structure of the low energy expansion of genus-one Type II superstring amplitudes. These modular graph forms are multiple sums associated with decorated Feynman graphs on the world-sheet torus. The action of standard differential operators on these modular graph forms admits an algebraic representation on the decorations. First order differential operators are used to map general non-holomorphic modular graph functions to holomorphic modular forms. This map is used to provide proofs of the identities between modular graph functions for weight less than six conjectured in earlier work, by mapping these identities to relations between holomorphic modular forms which are proven by holomorphic methods. The map is further used to exhibit the structure of identities at arbitrary weight.

  2. Colloid-Associated Radionuclide Concentration Limits: ANL

    International Nuclear Information System (INIS)

    The purpose and scope of this report is to describe the analysis of available colloidal data from waste form corrosion tests at Argonne National Laboratory (ANL) to extract characteristics of these colloids that can be used in modeling their contribution to the source term for sparingly soluble radioelements (e.g., Pu). Specifically, the focus is on developing a useful description of the following waste form colloid characteristics: (1) composition, (2) size distribution, and (3) quantification of the rate of waste form colloid generation. The composition and size distribution information are intended to support analysis of the potential transport of the sparingly soluble radionuclides associated with the waste form colloids. The rate of colloid generation is intended to support analysis of the waste form colloid-associated radionuclide concentrations. In addressing the above characteristics, available data are interpreted to address mechanisms controlling colloid formation and stability. This report was developed in accordance with the ''Technical Work Plan for Waste Form Degradation Process Model Report for SR'' (CRWMS M and O 2000). Because the end objective is to support the source term modeling we have organized the conclusions into two categories: (1) data analysis conclusions and (2) recommendations for colloid source term modeling. The second category is included to facilitate use of the conclusions from the data analysis in the abstraction of a colloid source term model. The data analyses and conclusions that are presented in this report are based on small-scale laboratory tests conducted on a limited number of waste glass compositions and spent fuel types

  3. Topics on the FORM software; Topicos do software FORM

    Energy Technology Data Exchange (ETDEWEB)

    Costa Jorge, Patricia M. da; Peres, Patricia Duarte [Universidade Catolica de Petropolis, RJ (Brazil). Dept. de Ciencia da Computacao

    1997-06-01

    These notes studies the compilation with FORM software as applied to high energy physics, covering the following topics: Command structures, statistics and numbers, Dirac matrices, optimization control, Gamma matrices, errors and polynomial substitution

  4. FormTracer - A Mathematica Tracing Package Using FORM

    CERN Document Server

    Cyrol, Anton K; Strodthoff, Nils

    2016-01-01

    We present FormTracer, a high-performance, general purpose, easy-to-use Mathematica tracing package which uses FORM. It supports arbitrary space and spinor dimensions as well as an arbitrary number of simple compact Lie groups. While keeping the usability of the Mathematica interface, it relies on the efficiency of FORM. An additional performance gain is achieved by a decomposition algorithm that avoids redundant traces in the product tensors spaces. FormTracer supports a wide range of syntaxes which endows it with a high flexibility. Mathematica notebooks that automatically install the package and guide the user through performing standard traces in space-time, spinor and gauge-group spaces are provided.

  5. Quantum modular forms, mock modular forms, and partial theta functions

    Science.gov (United States)

    Kimport, Susanna

    Defined by Zagier in 2010, quantum modular forms have been the subject of an explosion of recent research. Many of these results are aimed at discovering examples of these functions, which are defined on the rational numbers and have "nice" modularity properties. Though the subject is in its early stages, numerous results (including Zagier's original examples) show these objects naturally arising from many areas of mathematics as limits of other modular-like functions. One such family of examples is due to Folsom, Ono, and Rhoades, who connected these new objects to partial theta functions (introduced by Rogers in 1917) and mock modular forms (about which there is a rich theory, whose origins date back to Ramanujan in 1920). In this thesis, we build off of the work of Folsom, Ono, and Rhoades by providing an infinite family of quantum modular forms of arbitrary positive half-integral weight. Further, this family of quantum modular forms "glues" mock modular forms to partial theta functions and is constructed from a so-called "universal" mock theta function by extending a method of Eichler and Zagier (originally defined for holomorphic Jacobi forms) into a non-holomorphic setting. In addition to the infinite family, we explore the weight 1/2 and 3/2 functions in more depth. For both of these weights, we are able to explicitly write down the quantum modular form, as well as the corresponding "errors to modularity," which can be shown to be Mordell integrals of specific theta functions and, as a consequence, are real-analytic functions. Finally, we turn our attention to the partial theta functions associated with these low weight examples. Berndt and Kim provide asymptotic expansions for a certain class of partial theta functions as q approaches 1 radially within the unit disk. Here, we extend this work to not only obtain asymptotic expansions for this class of functions as q approaches any root of unity, but also for a certain class of derivatives of these functions

  6. The Electrostatic Screening Length in Concentrated Electrolytes Increases with Concentration

    OpenAIRE

    Smith, Alexander M.; Lee, Alpha A.; Perkin, Susan

    2016-01-01

    According to classical electrolyte theories interactions in dilute (low ion density) electrolytes decay exponentially with distance, with the Debye screening length the characteristic length-scale. This decay length decreases monotonically with increasing ion concentration, due to effective screening of charges over short distances. Thus within the Debye model no long-range forces are expected in concentrated electrolytes. Here we reveal, using experimental detection of the interaction betwee...

  7. Characteristic structure of star-forming clouds

    CERN Document Server

    Myers, Philip C

    2015-01-01

    This paper gives a new way to diagnose the star-forming potential of a molecular cloud region from the probability density function of its column density (N-pdf). It gives expressions for the column density and mass profiles of a symmetric filament having the same N-pdf as a filamentary region. The central concentration of this characteristic filament can distinguish regions and can quantify their fertility for star formation. Profiles are calculated for N-pdfs which are pure lognormal, pure power law, or a combination. In relation to models of singular polytropic cylinders, characteristic filaments can be unbound, bound, or collapsing depending on their central concentration. Such filamentary models of the dynamical state of N-pdf gas are more relevant to star-forming regions than are models of spherical collapse. The star formation fertility of a bound or collapsing filament is quantified by its mean mass accretion rate when in radial free fall. For a given mass per length, the fertility increases with the ...

  8. Altering prolactin concentrations in sows.

    Science.gov (United States)

    Farmer, C

    2016-07-01

    Prolactin has a multiplicity of actions, but it is of particular importance in gestating and lactating animals. In sows, it is involved in the control of mammary development and also holds essential roles in the lactogenic and galactopoietic processes. Furthermore, low circulating concentrations of prolactin are associated with the agalactia syndrome. The crucial role of prolactin makes it important to understand the various factors that can alter its secretion. Regulation of prolactin secretion is largely under the negative control of dopamine, and dopamine agonists consistently decrease prolactin concentrations in sows. On the other hand, injections of dopamine antagonists can enhance circulating prolactin concentrations. Besides pharmacologic agents, many other factors can also alter prolactin concentrations in sows. The use of Chinese-derived breeds, for instance, leads to increased prolactin concentrations in lactating sows compared with standard European white breeds. Numerous husbandry and feeding practices also have a potential impact on prolactin concentrations in sows. Factors, such as provision of nest-building material prepartum, housing at farrowing, high ambient temperature, stress, transient weaning, exogenous thyrotropin-releasing factor, exogenous growth hormone-releasing factor, nursing frequency, prolonged photoperiod, fasting, increased protein and/or energy intake, altered energy sources, feeding high-fiber diets, sorghum ergot or plant extracts, were all studied with respect to their prolactinemic properties. Although some of these practices do indeed affect circulating prolactin concentrations, none leads to changes as drastic as those brought about by dopamine agonists or antagonists. It appears that the numerous factors regulating prolactin concentrations in sows are still not fully elucidated, and that studies to develop novel applicable ways of increasing prolactin concentrations in sows are warranted.

  9. Fiber Optic Particle Concentration Sensor

    Science.gov (United States)

    Boiarski, Anthony A.

    1986-01-01

    A particle concentration sensor would be useful in many industrial process monitoring applications where in situ measurements are required. These applications include determination of butterfat content of milk, percent insolubles in engine oil, and cell concentration in a bioreactor. A fiber optic probe was designed to measure particle concentration by monitoring the scattered light from the particle-light interaction at the end of a fiber-optic-based probe tip. Linear output was obtained from the sensor over a large range of particle loading for a suspension of 1.7 μm polystyrene microspheres in water and E. coli bacteria in a fermenter.

  10. High Concentration Suspensions Under Strong Tidal Flows

    Science.gov (United States)

    Kineke, G. C.; Milligan, T. G.; Heath, K. M.; Law, B. A.

    2006-12-01

    An experiment investigating the influence of high-concentration suspensions of fine sediments (fluid muds) on a quasi-steady flow was carried out in the Petitcodiac River, Moncton, New Brunswick, Canada in August 2006. Concurrent measurements of fluid properties (salinity, temperature, density), suspended-sediment concentration, current velocity and shear were made throughout the water column over portions of several tidal cycles. The Petitcodiac was chosen because of consistently high suspended-sediment concentrations (0.5- >200 g/L) and large tidal range (>4 m) producing strong current velocities (> 1.5 m/s). Thus the Peticodiac serves as an ideal natural flume for examining the behavior of muddy suspensions under both accelerating and decelerating flows. Instrumentation included a profiling package with paired electromagnetic current meters mounted 0.6 m apart, a CTD, and an Optical Backscatterance Sensor with a pump system for in situ calibrations. Approximately 1.5 hours after the passage of the tidal bore and a fully mixed turbulent flow, the water column begins to stratify and a high concentration bottom layer forms persisting through the ensuing ebb. Measured suspended-sediment concentrations reached 286 g/L at the bottom and low shear rates of 0.13 s-1 in the upper water column increased to ~0.5 s-1 through the lutocline 1 m above the bed, and decreased to approximately 0 within the fluid mud. Analysis is in progress and the data set provides an excellent means to test threshold conditions regarding suppression of turbulence by sediment-induced stratification and the carrying capacity of turbulent flows.

  11. Differential forms theory and practice

    CERN Document Server

    Weintraub, Steven H

    2014-01-01

    Differential forms are utilized as a mathematical technique to help students, researchers, and engineers analyze and interpret problems where abstract spaces and structures are concerned, and when questions of shape, size, and relative positions are involved. Differential Forms has gained high recognition in the mathematical and scientific community as a powerful computational tool in solving research problems and simplifying very abstract problems through mathematical analysis on a computer. Differential Forms, 2nd Edition, is a solid resource for students and professionals needing a solid g

  12. Cold-formed steel design

    CERN Document Server

    Yu, Wei-Wen

    2010-01-01

    The definitive text in the field, thoroughly updated and expanded Hailed by professionals around the world as the definitive text on the subject, Cold-Formed Steel Design is an indispensable resource for all who design for and work with cold-formed steel. No other book provides such exhaustive coverage of both the theory and practice of cold-formed steel construction. Updated and expanded to reflect all the important developments that have occurred in the field over the past decade, this Fourth Edition of the classic text provides you with more of the detailed, up-to-the-minute techni

  13. Quadratic minima and modular forms

    OpenAIRE

    Brent, Barry

    1998-01-01

    We give upper bounds on the size of the gap between the constant term and the next non-zero Fourier coefficient of an entire modular form of given weight for \\Gamma_0(2). Numerical evidence indicates that a sharper bound holds for the weights h \\equiv 2 . We derive upper bounds for the minimum positive integer represented by level two even positive-definite quadratic forms. Our data suggest that, for certain meromorphic modular forms and p=2,3, the p-order of the constant term is related to t...

  14. Fibrinogen concentrate in bleeding patients

    DEFF Research Database (Denmark)

    Wikkelsø, Anne; Lunde, Jens; Johansen, Mathias;

    2013-01-01

    Hypofibrinogenaemia is associated with increased morbidity and mortality, but the optimal treatment level, the use of preemptive treatment and the preferred source of fibrinogen remain disputed. Fibrinogen concentrate is increasingly used and recommended for bleeding with acquired haemostatic...

  15. Thermodynamic efficiency of solar concentrators.

    Science.gov (United States)

    Shatz, Narkis; Bortz, John; Winston, Roland

    2010-04-26

    The optical thermodynamic efficiency is a comprehensive metric that takes into account all loss mechanisms associated with transferring flux from the source to the target phase space, which may include losses due to inadequate design, non-ideal materials, fabrication errors, and less than maximal concentration. We discuss consequences of Fermat's principle of geometrical optics and review étendue dilution and optical loss mechanisms associated with nonimaging concentrators. We develop an expression for the optical thermodynamic efficiency which combines the first and second laws of thermodynamics. As such, this metric is a gold standard for evaluating the performance of nonimaging concentrators. We provide examples illustrating the use of this new metric for concentrating photovoltaic systems for solar power applications, and in particular show how skewness mismatch limits the attainable optical thermodynamic efficiency. PMID:20607882

  16. Process for purifying molybdenite concentrates

    Energy Technology Data Exchange (ETDEWEB)

    Austin, J.W.; Bradburn, R.G.; Cromwell, C.A.; Gratch, E.; Groiss, E.; Perkins, D.; Walker, R.A.

    1985-02-19

    An improved process is disclosed for the treatment of molybdenite concentrate to remove impurities, such as copper and lead therefrom. According to this process, ferrous chloride liquor is introduced into a reactor which is made of a material that can withstand leaching with the use of ferric chloride at elevated temperatures and pressures. Sodium or calcium chloride may also be added to the reactor which is then sealed and subjected to chlorination until the rise in temperature, due to the exothermicity of the reaction, produces the desired concentration of the ferric ion to leach the impurities present in the concentrate to a desired level. Upon completion of the chlorination, the molybdenite concentrate is introduced into the reactor and is leached therein. Finally, the resulting pulp is filtered and washed to obtain the desired purified product.

  17. DISSOLVED CONCENTRATION LIMITS OF RADIOACTIVE ELEMENTS

    Energy Technology Data Exchange (ETDEWEB)

    NA

    2004-11-22

    The purpose of this study is to evaluate dissolved concentration limits (also referred to as solubility limits) of elements with radioactive isotopes under probable repository conditions, based on geochemical modeling calculations using geochemical modeling tools, thermodynamic databases, field measurements, and laboratory experiments. The scope of this modeling activity is to predict dissolved concentrations or solubility limits for 14 elements with radioactive isotopes (actinium, americium, carbon, cesium, iodine, lead, neptunium, plutonium, protactinium, radium, strontium, technetium, thorium, and uranium) important to calculated dose. Model outputs for uranium, plutonium, neptunium, thorium, americium, and protactinium are in the form of tabulated functions with pH and log (line integral) CO{sub 2} as independent variables, plus one or more uncertainty terms. The solubility limits for the remaining elements are either in the form of distributions or single values. The output data from this report are fundamental inputs for Total System Performance Assessment for the License Application (TSPA-LA) to determine the estimated release of these elements from waste packages and the engineered barrier system. Consistent modeling approaches and environmental conditions were used to develop solubility models for all of the actinides. These models cover broad ranges of environmental conditions so that they are applicable to both waste packages and the invert. Uncertainties from thermodynamic data, water chemistry, temperature variation, and activity coefficients have been quantified or otherwise addressed.

  18. NETWORK CODING BY BEAM FORMING

    DEFF Research Database (Denmark)

    2013-01-01

    Network coding by beam forming in networks, for example, in single frequency networks, can provide aid in increasing spectral efficiency. When network coding by beam forming and user cooperation are combined, spectral efficiency gains may be achieved. According to certain embodiments, a method...... includes operating a user equipment of a plurality of user equipment in a network comprising a plurality of access points. The method also includes the user equipment forming a beam. The method further receives processing received signals from at least one of the plurality of access points at the user...... equipment. The forming the beam is configured to let different user equipment of the plurality of user equipment to receive different signals from the plurality of access points to achieve diversity by using different beams amongst the plurality of user equipment. The method additionally includes...

  19. Distances to star forming regions

    CERN Document Server

    Loinard, Laurent

    2014-01-01

    The determination of accurate distances to star-forming regions are discussed in the broader historical context of astronomical distance measurements. We summarize recent results for regions within 1 kpc and present perspectives for the near and more distance future.

  20. Movement in aesthetic form creation

    DEFF Research Database (Denmark)

    Thomsen, Bente Dahl

    2015-01-01

    This paper presents the good practice based experiences found when movement is used to strengthen form creation and to create flow in the process of artistic education. Faced with the design engineering students’ problems with creating forms with aesthetic statements, the experiences with movement...... inspired the thesis that the design engineers’ training in aesthetic form creation can be improved by integrating the movement potential into their education. The paper documents the on-going work on developing a model for embodied creation of form called ‘Somatechne model’. The study also identifies...... a lens to assess the students’ development of mind-body skills, known as ‘The Three Soma’. The Somatechne model also helps to identify the activity that gives the students the opportunity to develop their sensibility and thus aesthetic attention....

  1. Fields and Forms on -Algebras

    Indian Academy of Sciences (India)

    Cătălin Ciupală

    2005-02-01

    In this paper we introduce non-commutative fields and forms on a new kind of non-commutative algebras: -algebras. We also define the Frölicher–Nijenhuis bracket in the non-commutative geometry on -algebras.

  2. Detection of Life Forms Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Gaia Genomics proposes to develop an instrument for the detection of earthborn and/or planetary life forms that are based on a nucleic acid paradigm. Highly...

  3. Teorell instability in concentration polarization.

    Science.gov (United States)

    Abu-Rjal, Ramadan; Prigozhin, Leonid; Rubinstein, Isaak; Zaltzman, Boris

    2015-08-01

    We investigate the development of electro-osmotic (Teorell) oscillations at a weakly charged microporous membrane without a preimposed transmembrane electrolyte concentration drop. This drop, necessary for the occurrence of oscillations, develops spontaneously as a result of concentration polarization in the solution layers adjacent to the membrane. A three-layer model comprising a membrane flanked by two diffusion layers is proposed and analyzed for galvano- and potentiostatic regimes of operation. PMID:26382404

  4. BILINEAR FORMS AND LINEAR CODES

    Institute of Scientific and Technical Information of China (English)

    高莹

    2004-01-01

    Abraham Lempel et al[1] made a connection between linear codes and systems of bilinear forms over finite fields. In this correspondence, a new simple proof of a theorem in [1] is presented; in addition, the encoding process and the decoding procedure of RS codes are simplified via circulant matrices. Finally, the results show that the correspondence between bilinear forms and linear codes is not unique.

  5. Programmed form generation in design

    OpenAIRE

    V F Koleichuk

    1980-01-01

    This article distinguishes design research that is concerned with further developments of existing formal systems from fundamental research in technical or geometrical fields that is capable of opening up new form-generating programmes. A historical discussion includes analysis of an early series of 'spatial compositions' by the pioneer Soviet Constructivist artist and designer Aleksandr Rodchenko. The general character of serial form is discussed, and its relationship to the concept and the ...

  6. CRYSTALLINE CERAMIC WASTE FORMS: REFERENCE FORMULATION REPORT

    Energy Technology Data Exchange (ETDEWEB)

    Brinkman, K.; Fox, K.; Marra, J.

    2012-05-15

    The research conducted in this work package is aimed at taking advantage of the long term thermodynamic stability of crystalline ceramics to create more durable waste forms (as compared to high level waste glass) in order to reduce the reliance on engineered and natural barrier systems. Durable ceramic waste forms that incorporate a wide range of radionuclides have the potential to broaden the available disposal options and to lower the storage and disposal costs associated with advanced fuel cycles. Assemblages of several titanate phases have been successfully demonstrated to incorporate radioactive waste elements, and the multiphase nature of these materials allows them to accommodate variation in the waste composition. Recent work has shown that they can be successfully produced from a melting and crystallization process. The objective of this report is to explain the design of ceramic host systems culminating in a reference ceramic formulation for use in subsequent studies on process optimization and melt property data assessment in support of FY13 melter demonstration testing. The waste stream used as the basis for the development and testing is a combination of the projected Cs/Sr separated stream, the Trivalent Actinide - Lanthanide Separation by Phosphorous reagent Extraction from Aqueous Komplexes (TALSPEAK) waste stream consisting of lanthanide fission products, the transition metal fission product waste stream resulting from the transuranic extraction (TRUEX) process, and a high molybdenum concentration with relatively low noble metal concentrations. In addition to the combined CS/LN/TM High Mo waste stream, variants without Mo and without Mo and Zr were also evaluated. Based on the results of fabricating and characterizing several simulated ceramic waste forms, two reference ceramic waste form compositions are recommended in this report. The first composition targets the CS/LN/TM combined waste stream with and without Mo. The second composition targets

  7. Form 6 - gas balancing agreement

    International Nuclear Information System (INIS)

    In 1988, a special Committee of the Rocky Mountain Mineral Law Foundation undertook a project to draft a model from gas balancing agreement. This project was initiated at the request of a number of Foundation members who felt that a model form gas balancing agreement would facilitate the negotiation of operating agreement, since gas balancing issues had become sticking points in the process. The Committee was composed of attorneys representing a wide cross-section of the oil and gas industry including both major and independent oil companies, production companies with interstate pipeline affiliates, and private practitioners. The Committee attempted to address the more controversial issues in gas balancing with optional provisions in the Form. To facilitate the negotiation process, the number of optional provisions was minimized. This form may be used as an Appendix to the new A.A.P.L. Form 610-1989 Model Form Operating Agreement. This book includes provision of this Form which are: Ownership of gas production; Balancing of production accounts; Cash balancing upon depletion; Deliverability tests; Nominations; Statements; Payment of taxes; Operating expenses; Overproducing allowable; Payment of leasehold burdens; Operator's liability; Successors and assigns; Audits; Arbitration; and Operator's fees

  8. The Electrostatic Screening Length in Concentrated Electrolytes Increases with Concentration.

    Science.gov (United States)

    Smith, Alexander M; Lee, Alpha A; Perkin, Susan

    2016-06-16

    According to classical electrolyte theories interactions in dilute (low ion density) electrolytes decay exponentially with distance, with the Debye screening length the characteristic length scale. This decay length decreases monotonically with increasing ion concentration due to effective screening of charges over short distances. Thus, within the Debye model no long-range forces are expected in concentrated electrolytes. Here we reveal, using experimental detection of the interaction between two planar charged surfaces across a wide range of electrolytes, that beyond the dilute (Debye-Hückel) regime the screening length increases with increasing concentration. The screening lengths for all electrolytes studied-including aqueous NaCl solutions, ionic liquids diluted with propylene carbonate, and pure ionic liquids-collapse onto a single curve when scaled by the dielectric constant. This nonmonotonic variation of the screening length with concentration, and its generality across ionic liquids and aqueous salt solutions, demonstrates an important characteristic of concentrated electrolytes of substantial relevance from biology to energy storage. PMID:27216986

  9. Nanowires and nanoribbons formed by methylphosphonic acid.

    Science.gov (United States)

    Archanjo, B S; Carvalho, L A S; Rassa, M; Miquita, D R; de Oliveira, F A C; Cançado, L G; Agero, U; Plentz, F; Cury, L A; Gonzalez, J C; Moreira, R L; Paniago, R; Magalhães-Paniago, R; Neves, B R A

    2007-09-01

    The production and physical properties of nanowires and nanoribbons formed by methylphosphonic acid (MPA)--CH3PO(OH)2--were investigated. These structures are formed on an aluminum coated substrate when immersed in an ethanolic solution of MPA for several days. A careful investigation of the growth conditions resulted in a narrow window of solution concentrations and temperatures for the successful development of nanowires and nanoribbons. Several different techniques were employed to characterize these nanostructures: (1) Photoluminescence experiments showed a strong emission at 2.3 eV (green), which is visible to the naked eye; (2) X-ray diffraction experiments indicated a significant cristalinity, in agreement with atomic force microscopy (AFM) and transmission electron microscopy (TEM) morphology images, which show organized nano-scale wires and ribbons, (furthermore, AFM-Phase and TEM images also suggest that nanoribbons are formed by well-aligned nanowires); (3) Conductive-AFM experiments revealed an intermediary conductivity for these structures (10(-1)/Ohm x m), which is similar to some intrinsic semiconductors and; (4) finally, Infrared, Raman, and X-Ray Photoelectron Spectroscopies produced information about the contents, structure, and composition of both wires and ribbons. PMID:18019131

  10. Conjoint Forming - Technologies for Simultaneous Forming and Joining

    Science.gov (United States)

    Groche, P.; Wohletz, S.; Mann, A.; Krech, M.; Monnerjahn, V.

    2016-03-01

    The market demand for new products optimized for e. g. lightweight applications or smart components leads to new challenges in production engineering. Hybrid structures represent one promising approach. They aim at higher product performance by using a suitable combination of different materials. The developments of hybrid structures stimulate the research on joining of dissimilar materials. Since they allow for joining dissimilar materials without external heating technologies based on joining by plastic deformation seem to be of special attractiveness. The paper at hand discusses the conjoint forming approach. This approach combines forming and joining in one process. Two or more workpieces are joined while at least one workpiece is plastically deformed. After presenting the fundamental joining mechanisms, the conjoint forming approach is discussed comprehensively. Examples of conjoint processes demonstrate the effectiveness and reveal the underlying phenomena.

  11. A Wall of Funnels Concentrates Swimming Bacteria▿

    Science.gov (United States)

    Galajda, Peter; Keymer, Juan; Chaikin, Paul; Austin, Robert

    2007-01-01

    Randomly moving but self-propelled agents, such as Escherichia coli bacteria, are expected to fill a volume homogeneously. However, we show that when a population of bacteria is exposed to a microfabricated wall of funnel-shaped openings, the random motion of bacteria through the openings is rectified by tracking (trapping) of the swimming bacteria along the funnel wall. This leads to a buildup of the concentration of swimming cells on the narrow opening side of the funnel wall but no concentration of nonswimming cells. Similarly, we show that a series of such funnel walls functions as a multistage pump and can increase the concentration of motile bacteria exponentially with the number of walls. The funnel wall can be arranged along arbitrary shapes and cause the bacteria to form well-defined patterns. The funnel effect may also have implications on the transport and distribution of motile microorganisms in irregular confined environments, such as porous media, wet soil, or biological tissue, or act as a selection pressure in evolution experiments. PMID:17890308

  12. Measurement of Odour Concentration from Livestock Farm

    Directory of Open Access Journals (Sweden)

    Lukman Ismail

    2014-08-01

    Full Text Available Odourpollution originated from livestock farms is a form of harmful air pollution.Odour pollution causes health issues to the surrounding local communities. Yet, odour pollution issues have not been given deserving attention by the relevant authorities and the Malaysian public. To raise the awareness, this study highlights a case of odour pollution generated from cattle and buffalo farms in Bandar Baru Bangi, Selangor.Odour measurement was taken using an instrument called Concentration Meter Xp-369 Series III. Measurement was taken during various weather and times, usually on normal days and after rains. Observationswere conducted at different times inthe mornings, evenings and nights. Ten stations were selected as locations for measuring the odour concentration within two kilometres from the livestock farms. The results indicated that after rain odour concentration gave higher readings compared to those of normal days.This phenomenon was caused by the meteorological factors such as temperature, comparative humidity; and variation in wind speed and directions on normal days and after rains.Enhancement of livestock management is suggested for mitigating the odour pollution.

  13. Low concentration ratio solar array structural configuration

    Science.gov (United States)

    Nalbandian, S. J.

    1984-01-01

    The design and structural properties of a low concentration ratio solar array are discussed. The assembled module consists of six interconnected containers which are compactly stowed in a volume of 3.24 m(3) for delivery to orbit by the shuttle. The containers deploy in accordian fashion into a rectangular area of 19.4 x 68 meters and can be attached to the user spacecraft along the longitudinal centerline of the end container housing. Five rotary incremental actuators requiring about 8 watts each will execute the 180-degree rotation at each joint. Deployable masts (three per side) are used to extend endcaps from the housing in both directions. Each direction is extended by three masts requiring about 780 watts for about 27 minutes. Concentrator elements are extended by the endcaps and are supported by cable systems that are connected between the housings and endcaps. These power generating elements contain reflector panels which concentrate light onto the solar panels consisting of an aluminum radiator with solar cells positioned within the element base formed by the reflectors. A flat wire harness collects the power output of individual elements for transfer to the module container housing harnesses.

  14. White butterflies as solar photovoltaic concentrators

    Science.gov (United States)

    Shanks, Katie; Senthilarasu, S.; Ffrench-Constant, Richard H.; Mallick, Tapas K.

    2015-07-01

    Man’s harvesting of photovoltaic energy requires the deployment of extensive arrays of solar panels. To improve both the gathering of thermal and photovoltaic energy from the sun we have examined the concept of biomimicry in white butterflies of the family Pieridae. We tested the hypothesis that the V-shaped posture of basking white butterflies mimics the V-trough concentrator which is designed to increase solar input to photovoltaic cells. These solar concentrators improve harvesting efficiency but are both heavy and bulky, severely limiting their deployment. Here, we show that the attachment of butterfly wings to a solar cell increases its output power by 42.3%, proving that the wings are indeed highly reflective. Importantly, and relative to current concentrators, the wings improve the power to weight ratio of the overall structure 17-fold, vastly expanding their potential application. Moreover, a single mono-layer of scale cells removed from the butterflies’ wings maintained this high reflectivity showing that a single layer of scale cell-like structures can also form a useful coating. As predicted, the wings increased the temperature of the butterflies’ thorax dramatically, showing that the V-shaped basking posture of white butterflies has indeed evolved to increase the temperature of their flight muscles prior to take-off.

  15. Passive CO2 concentration in higher plants.

    Science.gov (United States)

    Sage, Rowan F; Khoshravesh, Roxana

    2016-06-01

    Photorespiratory limitations on C3 photosynthesis are substantial in warm, low CO2 conditions. To compensate, certain plants evolved mechanisms to actively concentrate CO2 around Rubisco using ATP-supported CO2 pumps such as C4 photosynthesis. Plants can also passively accumulate CO2 without additional ATP expenditure by localizing the release of photorespired and respired CO2 around Rubisco that is diffusively isolated from peripheral air spaces. Passive accumulation of photorespired CO2 occurs when glycine decarboxylase is localized to vascular sheath cells in what is termed C2 photosynthesis, and through forming sheaths of chloroplasts around the periphery of mesophyll cells. The peripheral sheaths require photorespired CO2 to re-enter chloroplasts where it can be refixed. Passive accumulation of respiratory CO2 is common in organs such as stems, fruits and flowers, due to abundant heterotrophic tissues and high diffusive resistance along the organ periphery. Chloroplasts within these organs are able to exploit this high CO2 to reduce photorespiration. CO2 concentration can also be enhanced passively by channeling respired CO2 from roots and rhizomes into photosynthetic cells of stems and leaves via lacunae, aerenchyma and the xylem stream. Through passive CO2 concentration, C3 species likely improved their carbon economy and maintained fitness during episodes of low atmospheric CO2. PMID:27058940

  16. Methods for macro concentration speciation (>106 M)

    International Nuclear Information System (INIS)

    The range of topics covered by the term 'speciation' varies from the determination of isotopic composition, through whether an element or nuclide is present and under which form, to the full identification of the molecular compound present or the isolation of species. Therefore, it is quite understandable that a rather large range of techniques may be applicable for speciation purposes and that none may be sufficient by itself to cover all purposes. We tried in this report to review on technologies available for speciation purposes in nuclear fuel cycle activities and to provide a reference document to guide researchers in choosing the most useful technique for his purposes by summarizing their characteristics. Particular attention was given to highlight the advantages and disadvantages/limitations of a given technique as well as, when suitable, expected or necessary future improvements. It was also attempted to indicate a 'recommended' application field, though this was not an easy task. In the present part, we concentrate on techniques available for macro concentration speciation with an arbitrary limit fixed around 10-6 M. However, one should be aware that some of the techniques discussed in the present may be also applicable for lower concentration (overlap with over Partim. of the whole report) and vice-versa. Then, we consider that the scope of the present can only be achieved considering the whole parts discussed at the OECD/NEA Workshop on evaluation of speciation technology held in October 1999 at JAERI/Tokai-mura. (author)

  17. Waste forms, packages, and seals working group summary

    Energy Technology Data Exchange (ETDEWEB)

    Sridhar, N. [Center Antonio, TX (United States); McNeil, M.B. [Nuclear Regulatory Commission, Washington, DC (United States)

    1995-09-01

    This article is a summary of the proceedings of a group discussion which took place at the Workshop on the Role of Natural Analogs in Geologic Disposal of High-Level Nuclear Waste in San Antonio, Texas on July 22-25, 1991. The working group concentrated on the subject of radioactive waste forms and packaging. Also included is a description of the use of natural analogs in waste packaging, container materials and waste forms.

  18. Antiproliferative Potential of Officinal Forms and Nanoparticles of Lithium Salts.

    Science.gov (United States)

    Lykov, A P; Poveshchenko, O V; Bondarenko, N A; Bogatova, N P; Makarova, O P; Konenkov, V I

    2016-04-01

    We studied the effect of officinal forms and nanoparticles of lithium carbonate and lithium citrate on proliferative activity of hepatoma-29 cells. Lithium carbonate nanoparticles suppressed proliferation of hepatoma-29 cells in lower concentrations than officinal form of this salt. The antiproliferative effect of lithium salts i activation of apoptosis and arrest of hepatoma-29 cells in the G2/M phase of the cell cycle. PMID:27165073

  19. Cast Stone Formulation At Higher Sodium Concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K. M.; Roberts, K. A.; Edwards, T. B.

    2013-09-17

    A low temperature waste form known as Cast Stone is being considered to provide supplemental Low Activity Waste (LAW) immobilization capacity for the Hanford site. Formulation of Cast Stone at high sodium concentrations is of interest since a significant reduction in the necessary volume of Cast Stone and subsequent disposal costs could be achieved if an acceptable waste form can be produced with a high sodium molarity salt solution combined with a high water to premix (or dry blend) ratio. The objectives of this study were to evaluate the factors involved with increasing the sodium concentration in Cast Stone, including production and performance properties and the retention and release of specific components of interest. Three factors were identified for the experimental matrix: the concentration of sodium in the simulated salt solution, the water to premix ratio, and the blast furnace slag portion of the premix. The salt solution simulants used in this study were formulated to represent the overall average waste composition. The cement, blast furnace slag, and fly ash were sourced from a supplier in the Hanford area in order to be representative. The test mixes were prepared in the laboratory and fresh properties were measured. Fresh density increased with increasing sodium molarity and with decreasing water to premix ratio, as expected given the individual densities of these components. Rheology measurements showed that all of the test mixes produced very fluid slurries. The fresh density and rheology data are of potential value in designing a future Cast Stone production facility. Standing water and density gradient testing showed that settling is not of particular concern for the high sodium compositions studied. Heat of hydration measurements may provide some insight into the reactions that occur within the test mixes, which may in turn be related to the properties and performance of the waste form. These measurements showed that increased sodium

  20. Cast Stone Formulation At Higher Sodium Concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K. M.; Roberts, K. A.; Edwards, T. B.

    2014-02-28

    A low temperature waste form known as Cast Stone is being considered to provide supplemental Low Activity Waste (LAW) immobilization capacity for the Hanford site. Formulation of Cast Stone at high sodium concentrations is of interest since a significant reduction in the necessary volume of Cast Stone and subsequent disposal costs could be achieved if an acceptable waste form can be produced with a high sodium molarity salt solution combined with a high water to premix (or dry blend) ratio. The objectives of this study were to evaluate the factors involved with increasing the sodium concentration in Cast Stone, including production and performance properties and the retention and release of specific components of interest. Three factors were identified for the experimental matrix: the concentration of sodium in the simulated salt solution, the water to premix ratio, and the blast furnace slag portion of the premix. The salt solution simulants used in this study were formulated to represent the overall average waste composition. The cement, blast furnace slag, and fly ash were sourced from a supplier in the Hanford area in order to be representative. The test mixes were prepared in the laboratory and fresh properties were measured. Fresh density increased with increasing sodium molarity and with decreasing water to premix ratio, as expected given the individual densities of these components. Rheology measurements showed that all of the test mixes produced very fluid slurries. The fresh density and rheology data are of potential value in designing a future Cast Stone production facility. Standing water and density gradient testing showed that settling is not of particular concern for the high sodium compositions studied. Heat of hydration measurements may provide some insight into the reactions that occur within the test mixes, which may in turn be related to the properties and performance of the waste form. These measurements showed that increased sodium

  1. Cast Stone Formulation At Higher Sodium Concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K. M.; Edwards, T. A.; Roberts, K. B.

    2013-10-02

    A low temperature waste form known as Cast Stone is being considered to provide supplemental Low Activity Waste (LAW) immobilization capacity for the Hanford site. Formulation of Cast Stone at high sodium concentrations is of interest since a significant reduction in the necessary volume of Cast Stone and subsequent disposal costs could be achieved if an acceptable waste form can be produced with a high sodium molarity salt solution combined with a high water to premix (or dry blend) ratio. The objectives of this study were to evaluate the factors involved with increasing the sodium concentration in Cast Stone, including production and performance properties and the retention and release of specific components of interest. Three factors were identified for the experimental matrix: the concentration of sodium in the simulated salt solution, the water to premix ratio, and the blast furnace slag portion of the premix. The salt solution simulants used in this study were formulated to represent the overall average waste composition. The cement, blast furnace slag, and fly ash were sourced from a supplier in the Hanford area in order to be representative. The test mixes were prepared in the laboratory and fresh properties were measured. Fresh density increased with increasing sodium molarity and with decreasing water to premix ratio, as expected given the individual densities of these components. Rheology measurements showed that all of the test mixes produced very fluid slurries. The fresh density and rheology data are of potential value in designing a future Cast Stone production facility. Standing water and density gradient testing showed that settling is not of particular concern for the high sodium compositions studied. Heat of hydration measurements may provide some insight into the reactions that occur within the test mixes, which may in turn be related to the properties and performance of the waste form. These measurements showed that increased sodium

  2. Diverse microbial species survive high ammonia concentrations

    Science.gov (United States)

    Kelly, Laura C.; Cockell, Charles S.; Summers, Stephen

    2012-04-01

    Planetary protection regulations are in place to control the contamination of planets and moons with terrestrial micro-organisms in order to avoid jeopardizing future scientific investigations relating to the search for life. One environmental chemical factor of relevance in extraterrestrial environments, specifically in the moons of the outer solar system, is ammonia (NH3). Ammonia is known to be highly toxic to micro-organisms and may disrupt proton motive force, interfere with cellular redox reactions or cause an increase of cell pH. To test the survival potential of terrestrial micro-organisms exposed to such cold, ammonia-rich environments, and to judge whether current planetary protection regulations are sufficient, soil samples were exposed to concentrations of NH3 from 5 to 35% (v/v) at -80°C and room temperature for periods up to 11 months. Following exposure to 35% NH3, diverse spore-forming taxa survived, including representatives of the Firmicutes (Bacillus, Sporosarcina, Viridibacillus, Paenibacillus, Staphylococcus and Brevibacillus) and Actinobacteria (Streptomyces). Non-spore forming organisms also survived, including Proteobacteria (Pseudomonas) and Actinobacteria (Arthrobacter) that are known to have environmentally resistant resting states. Clostridium spp. were isolated from the exposed soil under anaerobic culture. High NH3 was shown to cause a reduction in viability of spores over time, but spore morphology was not visibly altered. In addition to its implications for planetary protection, these data show that a large number of bacteria, potentially including spore-forming pathogens, but also environmentally resistant non-spore-formers, can survive high ammonia concentrations.

  3. Study on Behavior of Carbon Reduction of Monazite Concentrate

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The behavior of monazite concentrate reduced by carbon, especially the decomposed procedure of rare earth phosphates, was investigated by X-ray diffraction , electron probe, TG method and chemical analysis. The results show that rare earth phosphates in monazite concentrate can be reduced to their oxides, among them the decomposition processes of cerium phosphate are not in step with lanthanum phosphate, neodymium phosphate and so on, and the phosphorus was volatilized into air in simple form.

  4. New Visions on Form and Growth

    Energy Technology Data Exchange (ETDEWEB)

    Howard, M [Department of Mathematics, Imperial College-University of London, UK (United Kingdom)

    2005-03-11

    It is now nearly 90 years since the publication of D'Arcy Thompson's book On Growth and Form, a classic work that attempted a unification of pattern-forming phenomena in systems ranging from inanimate to living matter. Thompson's book came early in the development of mathematical techniques in biology. His work has had enormous influence in succeeding decades and has helped inspire the rapid growth in the application of theoretical techniques to biological phenomena. Pelce's book New Visions on Form and Growth takes its inspiration and title directly from D'Arcy Thompson. Furthermore, Pelce attempts what could not be achieved in D'Arcy Thompson's time, namely the presentation of a quantitative analysis of pattern forming phenomena. However, it should be emphasised that the vast majority of this book is concerned with inanimate matter, with rather little discussion of biology. The book begins with a presentation of the basic physics, including surface tension, first-order phase transition kinetics and a brief outline of chemical kinetics. With the essential physics established, Pelce then investigates simple growth forms, before showing how these regular geometries are destabilized into more complex forms by instabilities. The problem of velocity selection of growing patterns is then extensively discussed, before the question of (secondary) instabilities of the more complex growth forms is analysed. A chapter on stochastic patterns is also included. For the most part, the book concentrates on a few intensively studied pattern forming systems in physics, particularly viscous fingering in Hele-Shaw cells, the growth of dendrites, electrodeposition, flames, and, in the chapter on stochastic patterns, diffusion-limited aggregation. Only in a rather brief final chapter is a more speculative link made with biological pattern formation and morphogenesis. In general, I found the book to be a useful reference work on the theory of pattern

  5. Pre-exposure to moving form enhances static form sensitivity.

    Directory of Open Access Journals (Sweden)

    Thomas S A Wallis

    Full Text Available BACKGROUND: Motion-defined form can seem to persist briefly after motion ceases, before seeming to gradually disappear into the background. Here we investigate if this subjective persistence reflects a signal capable of improving objective measures of sensitivity to static form. METHODOLOGY/PRINCIPAL FINDINGS: We presented a sinusoidal modulation of luminance, masked by a background noise pattern. The sinusoidal luminance modulation was usually subjectively invisible when static, but visible when moving. We found that drifting then stopping the waveform resulted in a transient subjective persistence of the waveform in the static display. Observers' objective sensitivity to the position of the static waveform was also improved after viewing moving waveforms, compared to viewing static waveforms for a matched duration. This facilitation did not occur simply because movement provided more perspectives of the waveform, since performance following pre-exposure to scrambled animations did not match that following pre-exposure to smooth motion. Observers did not simply remember waveform positions at motion offset, since removing the waveform before testing reduced performance. CONCLUSIONS/SIGNIFICANCE: Motion processing therefore interacts with subsequent static visual inputs in a way that can improve performance in objective sensitivity measures. We suggest that the brief subjective persistence of motion-defined forms that can occur after motion offsets is a consequence of the decay of a static form signal that has been transiently enhanced by motion processing.

  6. Sixth-Form Colleges: An Endangered Organisational Form?

    Science.gov (United States)

    Stoten, David William

    2014-01-01

    The sixth-form college sector is often marginalised in policy and academic discourse, where the much larger school and further education sectors dominate. This paper sets out to describe the sector's key features, assess its position within the wider education system and consider its future in an increasingly competitive education market. The…

  7. High concentration linear Fresnel reflectors

    International Nuclear Information System (INIS)

    Highlights: • Linear Fresnel reflectors (LFRs) have great potential for cost reductions. • Concentration in the receiver central strip as high as in trough collectors. • Daily constant flux map in the receiver if the filling factor is adequately designed. • High concentration variation between summer and winter for N–S configurations. - Abstract: The late exponential development of Concentrating Solar Power (CSP) technology has driven to a very high power installed worldwide, but with no time for global optimization of the technology. High feed-in-tariffs have concentrated investments on trough collectors and central towers, previously studied during the 1980s. Linear Fresnel reflectors (LFRs) are regarded as a low efficiency technology, which is mainly due to very little previous research. However, the use of slightly bent mirrors drives to high concentration ratios, with obvious cost advantages over other CSP technologies. This paper studies the radiation flux obtained in a flat receiver using different mirror shapes, and analyzes its variation along the year. Linear Fresnel reflector design variables are reviewed, and a Ray Tracing model of the Fresdemo prototype is carried out. Results show higher performances than expected

  8. Forms of organic phosphorus in wetland soils

    Directory of Open Access Journals (Sweden)

    A. W. Cheesman

    2014-06-01

    Full Text Available Phosphorus (P cycling in freshwater wetlands is dominated by biological mechanisms, yet there has been no comprehensive examination of the forms of biogenic P (i.e. forms derived from biological activity in wetland soils. We used solution 31P NMR spectroscopy to identify and quantify P forms in surface soils of 28 palustrine wetlands spanning a range of climatic, hydro-geomorphic and vegetation types. Total P concentrations ranged between 51 and 3516 μg P g, of which an average of 58% was extracted in a single-step NaOH–EDTA extraction procedure. The extracts contained a broad range of P forms, including phosphomonoesters (averaging 24% of the total soil P, phosphodiesters (averaging 10% of total P, phosphonates (up to 4% of total P, and both pyrophosphate and long-chain polyphosphates (together averaging 6% of total P. Soil P composition was predicted by two key biogeochemical properties: organic matter content and pH. For example, stereoisomers of inositol hexakisphosphate were detected exclusively in acidic soils with high mineral content, while phosphonates were detected in soils from a broad range of vegetation and hydrogeomorphic types, but only under acidic conditions. Conversely inorganic polyphosphates occurred in a broad range of wetland soils and their abundance appears to reflect more broadly that of a "substantial" and presumably active microbial community with a significant relationship between total inorganic polyphosphates and microbial biomass P. We conclude that soil P composition varies markedly among freshwater wetlands, but can be predicted by fundamental soil properties.

  9. Investigation of alumina samples cast from concentrated polymer suspensions

    Science.gov (United States)

    Angyal, L.; Mátyás-Karácsony, Zs; Kállay-Menyhárd, A.; Bánhegyi, Gy

    2016-04-01

    In this research we investigated a new ceramic forming process. The technology is based on a concentrated ceramic suspension with ethylene acrylic acid copolymer binder system. After the forming procedure to get the final products, the samples were dried, debinded and sintered on high temperature. The samples were studied by different ways during the process: rheological studies, surface properties (optical and scanning electron microscopy), mercury porosimetry.

  10. Method of forming structural heliostat

    Science.gov (United States)

    Anderson, Alfred J.

    1984-06-26

    In forming a heliostat having a main support structure and pivoting and tilting motors and gears and a mirror module for reflecting solar energy onto a collector, the improvement characterized by a method of forming the mirror module in which the mirror is laid upon a solid rigid supporting bed in one or more sections, with or without focusing; a mirror backing sheet is applied by first applying respective thin layers of silicone grease and, thereafter, progressively rolling application to eliminate air bubbles; followed by affixing of a substrate assembly to the mirror backing sheet to form a mirror module that does not curve because of thermally induced stresses and differential thermal expansion or contraction effects. The silicone grease also serves to dampen fluttering of the mirror and protect the mirror backside against adverse effects of the weather. Also disclosed are specific details of preferred embodiments.

  11. Amorphous drugs and dosage forms

    DEFF Research Database (Denmark)

    Grohganz, Holger; Löbmann, K.; Priemel, P.;

    2013-01-01

    The transformation to an amorphous form is one of the most promising approaches to address the low solubility of drug compounds, the latter being an increasing challenge in the development of new drug candidates. However, amorphous forms are high energy solids and tend to recry stallize. New...... formulation principles are needed to ensure the stability of amorphous drug forms. The formation of solid dispersions is still the most investigated approach, but additional approaches are desirable to overcome the shortcomings of solid dispersions. Spatial separation by either coating or the use of micro......-containers has shown potential to prevent or delay recrystallization. Another recent approach is the formation of co-amorphous mixtures between either two drugs or one drug and one low molecular weight excipient. Molecular interactions between the two molecules provide an energy barrier that has to be overcome...

  12. Mono Digital Wordlist: Presentation Form

    Directory of Open Access Journals (Sweden)

    Kenneth S. Olson

    2009-01-01

    Full Text Available This paper presents a 204-item digital wordlist of Mono, an Ubangian language spoken in the Democratic Republic of the Congo. The wordlist includes orthographic and broad phonetic transcriptions of each word, French and English glosses, an individual WAV recording of each item, GIF images of the original field transcriptions, and metadata for resource discovery. An archival form of the wordlist was deposited into an institutional archive (the SIL Language and Culture Archives and includes the original WAV digital recording, descriptive markup encoding of the wordlist in XML employing Unicode 5.1 transcription, TIFF images of the original field transcriptions, and the metadata record. The presentation form was then generated directly from the archival form.

  13. Induction interview form in EDH

    CERN Multimedia

    Information technology Department, AIS (Administrative Information Services) Group

    2007-01-01

    As part of the efforts to rationalise administrative procedures, the IT and HR Departments have developed a new EDH form for induction interviews, which can be accessed using the link below. In accordance with Administrative Circular No. 2 ('Recruitment, Appointment and possible developments regarding the contractual position of Staff Members', Rev. 3), the work and training objectives to be achieved during the probation period shall be specified in writing to all new staff members during an induction interview. The interview shall take place between the new staff member and his supervisor within six weeks of his taking up his duties at the latest. https://edh.cern.ch/Document/MAPS/Induction1) (or from the EDH desktop, by clicking on 'Other Tasks' and going to the 'HR & Training' heading) Please note that this form is to be used exclusively for new staff members. A separate EDH form will be developed for fellows.Information technology Department, AIS (Administrative Information Services) Group Human Re...

  14. Induction interview form in EDH

    CERN Multimedia

    Information technology Department, AIS (Administrative Information Services) Group,

    2007-01-01

    As part of the efforts to rationalise administrative procedures, the IT and HR Departments have developed a new EDH form for induction interviews, which can be accessed using the link below. In accordance with Administrative Circular No. 2 ('Recruitment, Appointment and possible developments regarding the contractual position of Staff Members', Rev. 3), the work and training objectives to be achieved during the probation period shall be specified in writing to all new staff members during an induction interview. The interview shall take place between the new staff member and his supervisor within six weeks of him taking up his duties at the latest. https://edh.cern.ch/Document/MAPS/Induction (or from the EDH desktop, by clicking on 'Other Tasks' and going to the 'HR & Training' heading) Please note that this form is to be used exclusively for new staff members. A separate EDH form will be developed for fellows. Information technology Department, AIS (Administrative Information Services) Group Human...

  15. Concentration Bounds for Stochastic Approximations

    CERN Document Server

    Frikha, Noufel

    2012-01-01

    We obtain non asymptotic concentration bounds for two kinds of stochastic approximations. We first consider the deviations between the expectation of a given function of the Euler scheme of some diffusion process at a fixed deterministic time and its empirical mean obtained by the Monte-Carlo procedure. We then give some estimates concerning the deviation between the value at a given time-step of a stochastic approximation algorithm and its target. Under suitable assumptions both concentration bounds turn out to be Gaussian. The key tool consists in exploiting accurately the concentration properties of the increments of the schemes. For the first case, as opposed to the previous work of Lemaire and Menozzi (EJP, 2010), we do not have any systematic bias in our estimates. Also, no specific non-degeneracy conditions are assumed.

  16. Tourism forms and social sustainability

    OpenAIRE

    Onni, Giuseppe

    2012-01-01

    Sardinia offers a field to study the evolution of the tourist politics, above all in comparison to the relationships between tourist and local society, because it has been, and it is still, one of the best destinations of trip both in the set of the international tourism and for the one who seeks niche forms, however the tourist politics, that have driven the development of the different forms, have been driven in meaningful way, in time, from what that can be defined the tourist ...

  17. Differential forms on electromagnetic networks

    CERN Document Server

    Balasubramanian, N V; Sen Gupta, D P

    2013-01-01

    Differential Forms on Electromagnetic Networks deals with the use of combinatorial techniques in electrical circuit, machine analysis, and the relationship between circuit quantities and electromagnetic fields. The monograph is also an introduction to the organization of field equations by the methods of differential forms. The book covers topics such as algebraic structural relations in an electric circuit; mesh and node-pair analysis; exterior differential structures; generalized Stoke's theorem and tensor analysis; and Maxwell's electromagnetic equation. Also covered in the book are the app

  18. Front-Form Chiral Multiplets

    CERN Document Server

    Gómez-Rocha, María

    2012-01-01

    In this article we point out that the unitary transformation that relates the chiral basis $\\{R; I J^{PC}\\}$ and the $\\{I; ^{2S+1}L_J \\}$ basis, which was already derived for canonical spin in instant form, is also applicable in light-cone representations. From the most general expression for the Clebsch-Gordan coefficients of the Poincar\\'e group one can see that the chiral limit brings the angular momentum coupling into a simple form that permits a clear relation in terms of SU(2) Clebsch-Gordan coefficients. It provides a tool of measurement of chiral symmetry in relativistic composite systems.

  19. Positron flux concentrator - an update

    International Nuclear Information System (INIS)

    The type of concentrator that has been under study (on and off) for the last two years is shown. The work was started by Dave Sherden and Co., and the object of the study was (and still is) to determine the correct parameters which will give the correct field in the central region which captures the maximum number of e+'s from the target. This note contains two sections. The first is a simplified model which seems to agree with most of the measurements carried out. The second describes the set up, a typical example of the field's shape and amplitude and the electrical requirements for the final concentrator

  20. The relation of seismic activity and radon concentration

    Science.gov (United States)

    Kulali, Feride; Akkurt, Iskender; Vogiannis, Efstratios

    2014-10-01

    Radon, which is the largest source of natural ionizing radiation, reaches to surface as gas or dissolved form in the ground water. Emanation of radon can has a profile is disposed to increasing or decreasing depending on the effects of meteorological events or crust movements. In this work, the radon concentration in soil gas, which is transported from soil to AlphaGUARD, is continuously measured in Mytilene (Greece). A graph of radon concentration is prepared for comparison with simultaneous earthquake data. As a consequence of comparison, we determined that the radon concentration indicates anomalies before the earthquakes.

  1. The relation of seismic activity and radon concentration

    Energy Technology Data Exchange (ETDEWEB)

    Kulali, Feride, E-mail: feridekulali@gmail.com, E-mail: iskender@fef.sdu.edu.tr; Akkurt, İskender, E-mail: feridekulali@gmail.com, E-mail: iskender@fef.sdu.edu.tr [Suleyman Demirel University, Science and Art Faculty, Isparta-Turkey (Turkey); Vogiannis, Efstratios, E-mail: svog@env.aegean.gr [Department of Environmental Studies, University of the Aegean,Mytilene (Greece)

    2014-10-06

    Radon, which is the largest source of natural ionizing radiation, reaches to surface as gas or dissolved form in the ground water. Emanation of radon can has a profile is disposed to increasing or decreasing depending on the effects of meteorological events or crust movements. In this work, the radon concentration in soil gas, which is transported from soil to AlphaGUARD, is continuously measured in Mytilene (Greece). A graph of radon concentration is prepared for comparison with simultaneous earthquake data. As a consequence of comparison, we determined that the radon concentration indicates anomalies before the earthquakes.

  2. 48 CFR 53.301 - Standard forms.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false Standard forms. 53.301... AND FORMS FORMS Illustrations of Forms 53.301 Standard forms. This section illustrates the standard... order. The subsection numbers correspond with the standard form numbers (e.g., Standard Form 18...

  3. Slepian Spatial-Spectral Concentration on the Ball

    CERN Document Server

    Khalid, Zubair; McEwen, Jason D

    2014-01-01

    We formulate and solve the Slepian spatial-spectral concentration problem on the three-dimensional ball. Both the standard Fourier-Bessel and also the Fourier-Laguerre spectral domains are considered since the latter exhibits a number of practical advantages (spectral decoupling and exact computation). The Slepian spatial and spectral concentration problems are formulated as eigenvalue problems, the eigenfunctions of which form an orthogonal family of concentrated functions. Equivalence between the spatial and spectral problems is shown. The spherical Shannon number on the ball is derived, which acts as the analog of the space-bandwidth product in the Euclidean setting, giving an estimate of the number of concentrated eigenfunctions and thus the dimension of the space of functions that can be concentrated in both the spatial and spectral domains simultaneously. Various symmetries of the spatial region are considered that reduce considerably the computational burden of recovering eigenfunctions, either by deco...

  4. Education fees – New forms

    CERN Multimedia

    2015-01-01

    The application forms for the payment of education fees have been updated and are now available in the Admin e-guide (under the “Useful Documents” heading):   Payment of education fees (including language course fees) – AC12A (form to be used by staff members recruited before 1 January 2007, with the exception of former “local staff”).   Payment of education fees – AC12B (form to be used by staff members recruited on or after 1 January 2007, by fellows, scientific associates and guest professors and by former “local staff” whose contracts started before 1 January 2007). The Education Fees service will continue to accept the old forms until the end of the current academic year, i.e. until 31 August 2015. Members of the personnel are reminded that any false declaration or failure to declare information with a view to deceiving others or achieving a gain that would result in a financial loss for CERN or...

  5. Green Lubricants for Metal Forming

    DEFF Research Database (Denmark)

    Bay, Niels

    2010-01-01

    The increasing focus on legislation towards diminishing the impact on working environment as well as external environment has driven efforts to develop new, environmentally benign lubricants for metal forming. The present paper gives an overview of these efforts to substitute environmentally...

  6. Simerka - Quadratic Forms and Factorization

    OpenAIRE

    Lemmermeyer, Franz

    2011-01-01

    In this article we show that the Czech mathematician Vaclav Simerka discovered the factorization of (10^17-1)/9 using a method based on the class group of binary quadratic forms more than 120 years before Shanks and Schnorr developed similar algorithms. Simerka also gave the first examples of what later became known as Carmichael numbers.

  7. English Pidgins: Form and Function.

    Science.gov (United States)

    Mufwene, Salikoko S.

    1988-01-01

    Highlights similarities and variation in both form and function of English pidgins the world over. It is argued that English pidgins are related more by socio-historical conditions and directions of development than by details of their formal structure. Reference list includes 68 citations. (Author/DJD)

  8. Emerging Forms of Cultural Capital

    DEFF Research Database (Denmark)

    Prieur, Annick; Savage, Mike

    - the claims that there are forms of emotional, subcultural or national cultural capital at work - The claim about cosmopolitanism or an international orientation as a distinctive feature of the culturally privileged classes The paper responds to the first theme announced in the call for this conference...

  9. Polynomial Algebra in Form 4

    Science.gov (United States)

    Kuipers, J.

    2012-06-01

    New features of the symbolic algebra package Form 4 are discussed. Most importantly, these features include polynomial factorization and polynomial gcd computation. Examples of their use are shown. One of them is an exact version of Mincer which gives answers in terms of rational polynomials and 5 master integrals.

  10. Intersections: Form, Feeling, and Isomorphism

    Science.gov (United States)

    Reichling, Mary J.

    2004-01-01

    In this article, the author examines the intersections of three concepts, form, feeling, and isomorphism, in the work of Susanne Langer, as they are fundamental to an understanding of her aesthetic theory and to the construction of a philosophy of music and music education. These three concepts hold meanings that differ among musicians and…

  11. Technetium Immobilization Forms Literature Survey

    Energy Technology Data Exchange (ETDEWEB)

    Westsik, Joseph H.; Cantrell, Kirk J.; Serne, R. Jeffrey; Qafoku, Nikolla

    2014-05-01

    Of the many radionuclides and contaminants in the tank wastes stored at the Hanford site, technetium-99 (99Tc) is one of the most challenging to effectively immobilize in a waste form for ultimate disposal. Within the Hanford Tank Waste Treatment and Immobilization Plant (WTP), the Tc will partition between both the high-level waste (HLW) and low-activity waste (LAW) fractions of the tank waste. The HLW fraction will be converted to a glass waste form in the HLW vitrification facility and the LAW fraction will be converted to another glass waste form in the LAW vitrification facility. In both vitrification facilities, the Tc is incorporated into the glass waste form but a significant fraction of the Tc volatilizes at the high glass-melting temperatures and is captured in the off-gas treatment systems at both facilities. The aqueous off-gas condensate solution containing the volatilized Tc is recycled and is added to the LAW glass melter feed. This recycle process is effective in increasing the loading of Tc in the LAW glass but it also disproportionally increases the sulfur and halides in the LAW melter feed which increases both the amount of LAW glass and either the duration of the LAW vitrification mission or the required supplemental LAW treatment capacity.

  12. Form Filling with SCC in a Vertical Form

    DEFF Research Database (Denmark)

    Thrane, Lars Nyholm

    2004-01-01

    University of Denmark and the second largest ready-mix manufacturer in Denmark, 4K-Beton A/S. The aim is to identify the flow characteristic of SCC and the effect of concrete properties, casting technique, reinforcement configuration, and form geometry. A wall form of dimensions l = 3m, w = 0.3m, h =1m has....... Monitoring equipment has been produced and tested and is valuable as documentary evidence of the flow in combination with visual observations. In one experiment reinforcement gap sizes of 1.5 and 3⋅Dmax,agg have been applied and blocking occurred at 1.5⋅Dmax,agg. Pumping from the bottom corner at casting...... rate of 10 m/h resulted in hydrostatic pressure. Continuously shearing across the surface seems to have a positive effect on the surface quality (no blowholes)....

  13. Study on magnetic concentration of Nigerian Itakpe sinter concentrate to a Midrex-grade concentrate

    Directory of Open Access Journals (Sweden)

    Adewale O. Adeleke

    2009-10-01

    Full Text Available The sinter grade of the Nigerian Itakpe iron ore that assayed 63.63% Fe and 6.62% total acid gangue was subjected to both wet low-intensity magnetic separation (LIMS and wet high-intensity magnetic separation (WHIMS to upgrade it to Midrex-grade super-concentrate. Chemical analysis conducted on the super-concentrate samples from LIMS and WHIMS gave Fe content of 67.59% and 68.70%, and lower acid gangue of 1.55% and 3.22% respectively. However, screen distribution analysis results showed that the cumulative fractions passing 45-m sieve were 0.88% and 0.38% for LIMS and WHIMS super-concentrates respectively. These results indicate that the Fe and acid content determined for both LIMS and WHIMS meets the requirement for a Midrex-grade super-concentrate, while the fractions of the concentrate passing 45-m sieve are below the 30% upper limit for transportation to the reduction plant.

  14. Forms representing forms and linear spaces on hypersurfaces

    CERN Document Server

    Brandes, Julia

    2012-01-01

    A generalisation of Waring's problem, considered first by Arkhipov and Karatsuba, is the question of representing not an integer, but a given polynomial, as a sum of powers of linear polynomials. We investigate a related problem and prove a Hasse principle for the number of identical representations of a set of given forms by homogeneous polynomials of general shape. The result leads to sizeable improvements for estimates of the number of linear spaces on the intersection of hypersurfaces.

  15. An Unusual Variation of Surface Tension with Concentration of.Mixed Cationic-anionic Surfactants

    Institute of Scientific and Technical Information of China (English)

    肖进新; 暴艳霞

    2001-01-01

    There are two platforms in the surface tension vs. concentration curve (γ-lgC curve) of cationic-anionic surfactant mixtures. The first platform is the same as that of common surfactant solution, and the cross point is the CMC. After the CMC, the mixtures form precipitate. At higher concentration, the mixtures form homogeneous sloution.When the mixtures form homogeneous solution at high concentration. surface tension increases with concentration, the becomes constant.So the γ-lgC curve exhibits the second platform. The surface tension at the second platform increases by increasing molar ratio of two surfactants and polar group size of surfactants, and decreases with adding inorganic salts.

  16. Benign concentric annular macular dystrophy

    Directory of Open Access Journals (Sweden)

    Luísa Salles de Moura Mendonça

    2015-06-01

    Full Text Available The purpose of the authors is to show clinical findings of a patient with benign concentric annular macular dystrophy, which is an unusual condition, and part of the "bull’s eye" maculopathy differential diagnosis. An ophthalmologic examination with color perception, fluorescein angiography, and ocular electrophysiology was performed.

  17. Indoor radon concentration in Poland

    International Nuclear Information System (INIS)

    Preliminary survey of Rn concentration indoors by means of track detectors and y-ray dose rate with the use of TLD in almost 500 homes in selected areas of Poland was performed in the late 1980s. It was concluded that radon contributes 1.16 mSv i.e. about 46 per cent of the total natural environment ionizing radiation dose to the Polish population. Comparison of the average radon concentrations in 4 seasons of a year and in 3 groups of buildings: masonry, concrete and wood, revealed that the ground beneath the building structure is likely the dominant source of radon indoors. Since the National Atomic Energy Agency in its regulations of 1988-03-31 set up the permissible limit of the equilibrium equivalent concentration of radon in new buildings (equal 100 Bq/m3), the nation-scale survey project for radon in buildings has been undertaken. These regulations were supposed to take effect in 1995-01-01. The project has 3 objectives: to estimate the radiation exposure due to radon daughters received by Polish population to identify radon-prone areas in Poland to investigate dependence of the indoor radon concentrations on such parameters as: type of construction material, presence (or absence) of cellar under the building, number of floor

  18. Freeform optics for photovoltaic concentration

    OpenAIRE

    Benitez Gimenez, Pablo; Miñano Dominguez, Juan Carlos

    2012-01-01

    Freeform surfaces are the key of the state-of-the-art nonimaging optics to solve the challenges in concentration photovoltaics. Different families (FK, XR, FRXI) will be presented, based on the SMS 3D design method and Köhler homogenization.

  19. City scale pollen concentration variability

    Science.gov (United States)

    van der Molen, Michiel; van Vliet, Arnold; Krol, Maarten

    2016-04-01

    Pollen are emitted in the atmosphere both in the country-side and in cities. Yet the majority of the population is exposed to pollen in cities. Allergic reactions may be induced by short-term exposure to pollen. This raises the question how variable pollen concentration in cities are in temporally and spatially, and how much of the pollen in cities are actually produced in the urban region itself. We built a high resolution (1 × 1 km) pollen dispersion model based on WRF-Chem to study a city's pollen budget and the spatial and temporal variability in concentration. It shows that the concentrations are highly variable, as a result of source distribution, wind direction and boundary layer mixing, as well as the release rate as a function of temperature, turbulence intensity and humidity. Hay Fever Forecasts based on such high resolution emission and physical dispersion modelling surpass traditional hay fever warning methods based on temperature sum methods. The model gives new insights in concentration variability, personal and community level exposure and prevention. The model will be developped into a new forecast tool to serve allergic people to minimize their exposure and reduce nuisance, coast of medication and sick leave. This is an innovative approach in hay fever warning systems.

  20. Biodegradation kinetics at low concentrations (

    DEFF Research Database (Denmark)

    Toräng, Lars; Albrechtsen, Hans-Jørgen; Nyholm, Niels

    2000-01-01

    Aerobic biodegradation of 2,4-dichlorophenoxyacetic acid (2,4-D) was studied in groundwater added sediment fines. At concentrations at or below 1 mu g/L of 2,4-D degradation kinetic was of true first order without significant growth of specific degraders and with half-life for mineralization...

  1. NNWSI waste form testing program

    International Nuclear Information System (INIS)

    A waste form testing program has been developed to ensure that the release rate of radionuclides from the engineered barrier system will meet NRC and EPA regulatory requirements. Waste form performance testing will be done under unsaturated, low water availability conditions which represent the expected repository conditions. Testing will also be done under conditions of total immersion of the waste form in repository-type water to cover the possibility that localized portions of the repository might contain standing water. Testing of reprocesses waste forms for CHLW and DHLW will use reaction vessels fabricated from Topopah Spring tuff. Chemical elements which are expected to show the highest release rates in the mildly oxidizing environment of the Topopah Spring tuff horizon at Yucca Mountain are Np and Tc. To determine the effect of residual canister material and of corrosion products from the canister/overpack, waste form testing will be done in the presence of these materials. The release rate of all radionuclides which are subject to NRC and EPA regulations will be measured, and the interactive effects of the released radionuclide and the rock reaction vessels will be determined. The testing program for spent fuel will determine the release rate from bare spent fuel pellets and from Zircaloy clad spent fuel where the cladding contains minor defects. A metal testing program for Zircaloy will establish the expected lifetime of the cladding material. Estimation of the state of cladding for fuel presently in reactor pool storage will provide baseline data for Zircaloy containment credit. 9 references, 4 figures

  2. Research Timeline: Form-Focused Instruction and Second Language Acquisition

    Science.gov (United States)

    Nassaji, Hossein

    2016-01-01

    This article provides a timeline of research on form-focused instruction (FFI). Over the past 40 years, research on the role of instruction has undergone many changes. Much of the early research concentrated on determining whether formal instruction makes any difference in the development of learner language. This question was motivated in part by…

  3. Electro-Hydraulic Forming of Sheet Metals: Free-forming vs. Conical-die Forming

    Energy Technology Data Exchange (ETDEWEB)

    Rohatgi, Aashish; Stephens, Elizabeth V.; Davies, Richard W.; Smith, Mark T.; Soulami, Ayoub; Ahzi, Said

    2012-05-01

    This work builds upon our recent advances in quantifying high-rate deformation behavior of sheet metals, during electro-hydraulic forming (EHF), using high-speed imaging and digital image correlation techniques. Following recent publication of an earlier manuscript, resulting from this project, in the Journal of Materials Processing Technology, this manuscript further details our results and compares forming behavior when the process is carried out inside an open-die or a conical die. It is anticipated that quantitative information of the sheet deformation history, made possible by the experimental technique developed in this work, will improve our understanding on the roles of strain-rate and sheet-die interactions in enhancing the sheet metal formability during high-rate forming. This knowledge will be beneficial to the automotive industry and enable them to fabricate light-weight sheet parts out of Al and advanced high strength steels.

  4. Study on magnetic concentration of Nigerian Itakpe sinter concentrate to a Midrex-grade concentrate

    OpenAIRE

    Adewale O. Adeleke

    2009-01-01

    The sinter grade of the Nigerian Itakpe iron ore that assayed 63.63% Fe and 6.62% total acid gangue was subjected to both wet low-intensity magnetic separation (LIMS) and wet high-intensity magnetic separation (WHIMS) to upgrade it to Midrex-grade super-concentrate. Chemical analysis conducted on the super-concentrate samples from LIMS and WHIMS gave Fe content of 67.59% and 68.70%, and lower acid gangue of 1.55% and 3.22% respectively. However, screen distribution analysis results showed tha...

  5. Concentration Dependent Structure of Block Copolymer Solutions

    Science.gov (United States)

    Choi, Soohyung; Bates, Frank S.; Lodge, Timothy P.

    2015-03-01

    Addition of solvent molecules into block copolymer can induce additional interactions between the solvent and both blocks, and therefore expands the range of accessible self-assembled morphologies. In particular, the distribution of solvent molecules plays a key role in determining the microstructure and its characteristic domain spacing. In this study, concentration dependent structures formed by poly(styrene-b-ethylene-alt-propylene) (PS-PEP) solution in squalane are investigated using small-angle X-ray scattering. This reveals that squalane is essentially completely segregated into the PEP domains. In addition, the conformation of the PS block changes from stretched to nearly fully relaxed (i.e., Gaussian conformation) as amounts of squalane increases. NRF

  6. Nonfouling hydrogels formed from charged monomer subunits.

    Science.gov (United States)

    Dobbins, Sean C; McGrath, Daniel E; Bernards, Matthew T

    2012-12-13

    A critical challenge in the field of biomaterials is the often undesirable, but immediate, coating of implants with nonspecifically adsorbed proteins upon contact with bodily fluids. Prior research has shown that overall neutral materials containing a homologous arrangement of mixed charges exhibit nonfouling properties. This has been widely demonstrated for zwitterionic materials and more recently for coatings containing an equimolar mixture of positively and negatively charged monomer subunits. In this investigation it is demonstrated that nonfouling hydrogels can be formed through this approach, and the physical properties of the resulting materials are thoroughly characterized. In particular, hydrogels were formed from mixtures of [2-(methacryloyloxy)ethyl]trimethylammonium chloride (TM) and 3-sulfopropyl methacrylate potassium salt (SA) monomers with varying concentrations of a triethylene glycol dimethacrylate (TEGDMA) cross-linker. The swelling, weight percentage water, surface zeta potential, and compressional properties of the gels were characterized, and the nonfouling properties were demonstrated using enzyme-linked immunosorbant assays for both negatively charged fibrinogen and positively charged lysozyme. The results confirm that the TM:SA hydrogel systems have nonfouling properties that are equivalent to established nonfouling controls. Additionally, even though the gels were resistant to nonspecific protein adsorption, a composition analysis suggests that there is room to further improve the nonfouling performance because there is a slight enrichment of the SA monomer relative to the TM monomer. PMID:23189949

  7. Terra firma-forme dermatosis

    Directory of Open Access Journals (Sweden)

    Emel Erkek

    2012-01-01

    Full Text Available Terra firma-forme dermatosis is characterized by ′dirty′ brown-grey cutaneous patches and plaques that can simply be eradicated by forceful swabbing with alcohol pads. The pathogenesis has been attributed to abnormal and delayed keratinization. Although affected patients present with typical lesions, the disorder is not well-known by dermatologists. In this report, we describe two patients with terra firma-forme dermatosis in the setting of xerosis cutis and atopic dermatitis. From a clinical point of view, we lay emphasis on its unique expression and diagnosis/treatment. From a histological perspective, we highlight its resemblance to dermatosis neglecta and speculate on the role of ′neglect′ in a patient with seemingly adequate hygiene. The role of urea containing emollients in the development of this disorder remains to be determined.

  8. Free-form illumination optics

    Science.gov (United States)

    Mohedano, Rubén; Chaves, Julio; Hernández, Maikel

    2016-04-01

    In many illumination problems, the beam pattern needed and/or some geometrical constraints lead to very asymmetric design conditions. These asymmetries have been solved in the past by means of arrangements of rotationally symmetric or linear lamps aimed in different directions whose patterns overlap to provide the asymmetric prescriptions or by splitting one single lamp into several sections, each one providing a part of the pattern. The development of new design methods yielding smooth continuous free-form optical surfaces to solve these challenging design problems, combined with the proper CAD modeling tools plus the development of multiple axes diamond turn machines, give birth to a new generation of optics. These are able to offer the performance and other advanced features, such as efficiency, compactness, or aesthetical advantages, and can be manufactured at low cost by injection molding. This paper presents two examples of devices with free-form optical surfaces, a camera flash, and a car headlamp.

  9. Cyclodextrin Inclusion Polymers Forming Hydrogels

    Science.gov (United States)

    Li, Jun

    This chapter reviews the advances in the developments of supramolecular hydrogels based on the polypseudorotaxanes and polyrotaxanes formed by inclusion complexes of cyclodextrins threading onto polymer chains. Both physical and chemical supramolecular hydrogels of many different types are discussed with respect to their preparation, structure, property, and gelation mechanism. A large number of physical supramolecular hydrogels were formed induced by self-assembly of densely packed cyclodextrin rings threaded on polymer or copolymer chains acting as physical crosslinking points. The thermo-reversible and thixotropic properties of these physical supramolecular hydrogels have inspired their applications as injectable drug delivery systems. Chemical supramolecular hydrogels synthesized from polypseudorotaxanes and polyrotaxanes were based on the chemical crosslinking of either the cyclodextrin molecules or the included polymer chains. The chemical supramolecular hydrogels were often made biodegradable through incorporation of hydrolyzable threading polymers, end caps, or crosslinkers, for their potential applications as biomaterials.

  10. DISSOLVED CONCENTRATION LIMITS OF RADIOACTIVE ELEMENTS

    Energy Technology Data Exchange (ETDEWEB)

    P. Bernot

    2005-07-13

    The purpose of this study is to evaluate dissolved concentration limits (also referred to as solubility limits) of elements with radioactive isotopes under probable repository conditions, based on geochemical modeling calculations using geochemical modeling tools, thermodynamic databases, field measurements, and laboratory experiments. The scope of this activity is to predict dissolved concentrations or solubility limits for elements with radioactive isotopes (actinium, americium, carbon, cesium, iodine, lead, neptunium, plutonium, protactinium, radium, strontium, technetium, thorium, and uranium) relevant to calculated dose. Model outputs for uranium, plutonium, neptunium, thorium, americium, and protactinium are provided in the form of tabulated functions with pH and log fCO{sub 2} as independent variables, plus one or more uncertainty terms. The solubility limits for the remaining elements are either in the form of distributions or single values. Even though selection of an appropriate set of radionuclides documented in Radionuclide Screening (BSC 2002 [DIRS 160059]) includes actinium, transport of Ac is not modeled in the total system performance assessment for the license application (TSPA-LA) model because of its extremely short half-life. Actinium dose is calculated in the TSPA-LA by assuming secular equilibrium with {sup 231}Pa (Section 6.10); therefore, Ac is not analyzed in this report. The output data from this report are fundamental inputs for TSPA-LA used to determine the estimated release of these elements from waste packages and the engineered barrier system. Consistent modeling approaches and environmental conditions were used to develop solubility models for the actinides discussed in this report. These models cover broad ranges of environmental conditions so they are applicable to both waste packages and the invert. Uncertainties from thermodynamic data, water chemistry, temperature variation, and activity coefficients have been quantified or

  11. The Integral Form of Supergravity

    OpenAIRE

    Castellani, L.; Catenacci, R.; Grassi, P. A.

    2016-01-01

    By using integral forms we derive the superspace action of D=3, N=1 supergravity as an integral on a supermanifold. The construction is based on target space picture changing operators, here playing the role of Poincare' duals to the lower-dimensional spacetime surfaces embedded into the supermanifold. We show how the group geometrical action based on the group manifold approach interpolates between the superspace and the component supergravity actions, thus providing another proof of their e...

  12. Characterising rag-forming solids

    OpenAIRE

    Kupai, MM; Yang, F.; Harbottle, D; Moran, K.; Masliyah, J; Xu, Z.

    2013-01-01

    In oil sands froth treatment, an undesirable intermediate layer, often accumulates during the separation of water-oil emulsions. The layer referred to as rag layer is a complex mixture of water, oil, solids and interfacially active components. The presence of a rag layer has a detrimental impact on the separation of water and fine solids from diluted bitumen. The current study focuses on characterisation of solids from a rag layer forming stream of a naphthenic froth treatment plant in an att...

  13. The faintest star forming galaxies

    CERN Document Server

    Ranalli, P

    2003-01-01

    I briefly report on the X-ray detection of 10 radio sub-mJy sources in the 2 Ms Chandra observation of the Hubble Deep Field North region. These sources follow the same radio/X-ray luminosities relation which holds for nearby galaxies. Making use of this relation, X-ray number counts from star forming galaxies are predicted from the deep radio Log N-Log S's.

  14. The Integral Form of Supergravity

    CERN Document Server

    Castellani, L; Grassi, P A

    2016-01-01

    By using integral forms we derive the superspace action of D=3, N=1 supergravity as an integral on a supermanifold. The construction is based on target space picture changing operators, here playing the role of Poincare' duals to the lower-dimensional spacetime surfaces embedded into the supermanifold. We show how the group geometrical action based on the group manifold approach interpolates between the superspace and the component supergravity actions, thus providing another proof of their equivalence.

  15. Ngbugu digital wordlist: Presentation form

    Directory of Open Access Journals (Sweden)

    Kenneth S. Olson

    2007-01-01

    Full Text Available This paper presents a 204-item digital wordlist of Ngbugu, an Ubangian language spoken in Central African Republic. The wordlist includes orthographic and broad phonetic transcriptions of the words, French and English glosses, an individual WAV recording of each word, GIF images of the original field transcriptions, and metadata for resource discovery. This presentation form of the wordlist was generated from an archived version (Olson 2006 following the procedure laid out in Simons, Olson and Frank (2007.

  16. Pion structure form lattice QCD

    OpenAIRE

    Javadi Motaghi, Narjes

    2015-01-01

    In this thesis we use lattice QCD to compute the second Mellin moments of pion generalized parton distributions and pion electromagnetic form factors. For our calculations we are able to analyze a large set of gauge configurations with 2 dynamical flavours using non-perturbatively the improved Wilson-Sheikholeslami-Wohlert fermionic action pion masses ranging down to 151 MeV. By employing improved smearing we were able to suppress excited state contamination. However, our data in the ph...

  17. Coated particle waste form development

    International Nuclear Information System (INIS)

    Coated particle waste forms have been developed as part of the multibarrier concept at Pacific Northwest Laboratory under the Alternative Waste Forms Program for the Department of Energy. Primary efforts were to coat simulated nuclear waste glass marbles and ceramic pellets with low-temperature pyrolytic carbon (LT-PyC) coatings via the process of chemical vapor deposition (CVD). Fluidized bed (FB) coaters, screw agitated coaters (SAC), and rotating tube coaters were used. Coating temperatures were reduced by using catalysts and plasma activation. In general, the LT-PyC coatings did not provide the expected high leach resistance as previously measured for carbon alone. The coatings were friable and often spalled off the substrate. A totally different concept, thermal spray coating, was investigated at PNL as an alternative to CVD coating. Flame spray, wire gun, and plasma gun systems were evaluated using glass, ceramic, and metallic coating materials. Metal plasma spray coatings (Al, Sn, Zn, Pb) provided a two to three orders-of-magnitude increase in chemical durability. Because the aluminum coatings were porous, the superior leach resistance must be due to either a chemical interaction or to a pH buffer effect. Because they are complex, coated waste form processes rank low in process feasibility. Of all the possible coated particle processes, plasma sprayed marbles have the best rating. Carbon coating of pellets by CVD ranked ninth when compared with ten other processes. The plasma-spray-coated marble process ranked sixth out of eleven processes

  18. Fuzzy logic of Aristotelian forms

    Energy Technology Data Exchange (ETDEWEB)

    Perlovsky, L.I. [Nichols Research Corp., Lexington, MA (United States)

    1996-12-31

    Model-based approaches to pattern recognition and machine vision have been proposed to overcome the exorbitant training requirements of earlier computational paradigms. However, uncertainties in data were found to lead to a combinatorial explosion of the computational complexity. This issue is related here to the roles of a priori knowledge vs. adaptive learning. What is the a-priori knowledge representation that supports learning? I introduce Modeling Field Theory (MFT), a model-based neural network whose adaptive learning is based on a priori models. These models combine deterministic, fuzzy, and statistical aspects to account for a priori knowledge, its fuzzy nature, and data uncertainties. In the process of learning, a priori fuzzy concepts converge to crisp or probabilistic concepts. The MFT is a convergent dynamical system of only linear computational complexity. Fuzzy logic turns out to be essential for reducing the combinatorial complexity to linear one. I will discuss the relationship of the new computational paradigm to two theories due to Aristotle: theory of Forms and logic. While theory of Forms argued that the mind cannot be based on ready-made a priori concepts, Aristotelian logic operated with just such concepts. I discuss an interpretation of MFT suggesting that its fuzzy logic, combining a-priority and adaptivity, implements Aristotelian theory of Forms (theory of mind). Thus, 2300 years after Aristotle, a logic is developed suitable for his theory of mind.

  19. Concentrating Solar Power Fact Sheet

    Energy Technology Data Exchange (ETDEWEB)

    None

    2015-12-01

    This fact sheet is an overview of the Concentrating Solar Power (CSP) subprogram at the U.S. Department of Energy SunShot Initiative. CSP is a dispatchable, renewable energy option that uses mirrors to focus and concentrate sunlight onto a receiver, from which a heat transfer fluid carries the intense thermal energy to a power block to generate electricity. CSP systems can store solar energy to be used when the sun is not shining. It will help meet the nation’s goal of making solar energy fully cost-competitive with other energy sources by the end of the decade. Worldwide, CSP activity is rapidly scaling, with approximately 10 gigawatts (GW) in various stages of operation or development. In the United States alone, nearly 2 GW of CSP are in operation.

  20. Cylindrical acoustic levitator/concentrator

    Energy Technology Data Exchange (ETDEWEB)

    Kaduchak, Gregory (Los Alamos, NM); Sinha, Dipen N. (Los Alamos, NM)

    2002-01-01

    A low-power, inexpensive acoustic apparatus for levitation and/or concentration of aerosols and small liquid/solid samples having particulates up to several millimeters in diameter in air or other fluids is described. It is constructed from a commercially available, hollow cylindrical piezoelectric crystal which has been modified to tune the resonance frequency of the breathing mode resonance of the crystal to that of the interior cavity of the cylinder. When the resonance frequency of the interior cylindrical cavity is matched to the breathing mode resonance of the cylindrical piezoelectric transducer, the acoustic efficiency for establishing a standing wave pattern in the cavity is high. The cylinder does not require accurate alignment of a resonant cavity. Water droplets having diameters greater than 1 mm have been levitated against the force of gravity using; less than 1 W of input electrical power. Concentration of aerosol particles in air is also demonstrated.

  1. Vertical distribution of sediment concentration

    Institute of Scientific and Technical Information of China (English)

    Sai-hua HUANG; Zhi-lin SUN; Dan XU; Shan-shan XIA

    2008-01-01

    A simple formula is proposed to predict the vertical distribution of a suspended load concentration in a 2D steady turbulent flow.The proposed formula significantly improves the well-known Rouse formula where sediment concentration has an infinitely large value at the channel bottom and a zero value at the water surface.Based on this formula and the logarithmic ve-locity profile,a theoretical elementary function for the transport rate of a suspended load is developed.This equation improves the Einstein equation in which the unit-width suspended sediment discharge must be solved by numerical integration and a contra-diction between the lower limit of the integral and that of velocity distribution exists.

  2. Pelletizing of sulfide molybdenite concentrates

    Science.gov (United States)

    Palant, A. A.

    2007-04-01

    The results of a pelletizing investigation using various binding components (water, syrup, sulfite-alcohol distillery grains, and bentonite) of the flotation sulfide molybdenite concentrate (˜84% MoS2) from the Mongolian deposit are discussed. The use of syrup provides rather high-strength pellets (>3 N/pellet or >300 g/pellet) of the required size (2 3 mm) for the consumption of 1 kg binder per 100 kg concentrate. The main advantage of the use of syrup instead of bentonite is that the molybdenum cinder produced by oxidizing roasting of raw ore materials is not impoverished due to complete burning out of the syrup. This fact exerts a positive effect on the subsequent hydrometallurgical process, decreasing molybdenum losses related to dump cakes.

  3. Concentrated solar power: an overview

    International Nuclear Information System (INIS)

    Solar thermal power is a relatively new technology and a fine arrangement for the provision of Electrical Energy and Clean Energy in general .The concentrated solar offers a viable option for the Sunny Zones of the world. The efficiency of the System depends on a few factors like Area, Intensity of Sunlight, Type of receiver, Hybridisation etc. Solar Thermal Systems employ lenses or mirrors to focus a large area of sunlight onto a small area. Electrical power is produced when the concentrated light is impugned onto photovoltaic cell made surfaces or used to heat a transfer fluid for a conventional power plant. In this paper we give a brief overview of a baseline Solar Thermal Power Plant, Technological details, Cost and Benefit analysis, a glimpse of solar thermal power and future of solar thermal power. (author)

  4. Photovoltaic concentrator module improvements study

    Energy Technology Data Exchange (ETDEWEB)

    Levy, S.L.; Kerschen, K.A. (Black and Veatch, Kansas City, MO (United States)); Hutchison, G. (Solar Kinetics, Inc., Dallas, TX (United States)); Nowlan, M.J. (Spire Corp., Bedford, MA (United States))

    1991-08-01

    This report presents results of a project to design and fabricate an improved photovoltaic concentrator module. Using previous work as a baseline, this study conducted analyses and testing to select major module components and design features. The lens parquet and concentrator solar cell were selected from the highest performing, available components. A single 185X point-focus module was fabricated by the project team and tested at Sandia. Major module characteristics include a 6 by 4 compression-molded acrylic lens parquet (0.737 m{sup 2} area), twenty-four 0.2 ohms-cm, FZ, p-Si solar cells (1.56 cm{sup 2} area) soldered to ceramic substrates and copper heat spreaders, and an aluminized steel housing with corrugated bottom. This project marked the first attempt to use prismatic covers on solar cells in a high-concentration, point-focus application. Cells with 15 percent metallization were obtained, but problems with the fabrication and placement of prismatic covers on these cells lead to the decision not to use covers in the prototype module. Cell assembly fabrication, module fabrication, and module optical design activities are presented here. Test results are also presented for bare cells, cell assemblies, and module. At operating conditions of 981 watts/m{sup 2} DNI and an estimated cell temperature of 65{degrees}C, the module demonstrated an efficiency of 13.9 percent prior to stressed environmental exposure. 12 refs., 56 figs., 7 tabs.

  5. Coupling leaching of sphalerite concentrate

    Institute of Scientific and Technical Information of China (English)

    彭鹏; 谢惠琴; 卢立柱

    2004-01-01

    Coupling process of sphalerite concentrate leaching in H2 SO4-HNO3 and tetrachloroethylene extracting of sulfur was investigated. Effects of leaching temperature, leaching time, mass ratio of liquid to solid and tetrachloroethylene addition on zinc leaching processes were examined separately. SEM images of sphalerite concentrate and residues were performed by using JEM-6700F field emission scanning electron microscope. The relationship between the number of recycling and extraction ratio of zinc was studied. The results indicate that 99.6 % zinc is obtained after leaching for 3 h at 85 ℃ and pressure of 0.1 MPa O2, with 20 g sphalerite concentrate in 200 mL leaching solution containing 2.0 mol/L H2SO4 and 0.2 mol/L HNO3, in the presence of 10 mL C2Cl4. The leaching time of zinc is 50% shorter than that in the common leaching. The coupling effect is distinct. The recycled C2Cl4 exerts little influence on extraction ratio of zinc.

  6. Processing of rare earth concentrates

    Institute of Scientific and Technical Information of China (English)

    Pamela Alex; R. C. Hubli; A.K. Suri

    2005-01-01

    The paper describes process details for extraction of rare earths from an intermediate grade concentrate of Madhya Pradesh region in India and a South African slag. The xenotime concentrate obtained from the former place was an intermediate grade (47%) rare earth phosphate containing both monazite and xenotime. The South African slag was a low-grade waste product typically containing only 4% of rare earths. The rare earth resource concentrates have been treated individually by different methods such as alkali fusion and alkali leaching to convert them into their mixed oxides. Both types of materials have been processed and greater than 98% solubilization of metal values has been achieved in the intermediate grade xenotime and 80% from the South African slag. The residue of xenotime hydroxide has been washed thoroughly to collect the sodium phosphate, as by-product and the slurry pH have been adjusted to separate rare earths from thorium effectively. Other impurities such as uranium and iron have been removed by precipitation of rare earths by oxalic acid. It has been possible to recover >95% yttrium along with other rare earth oxides.

  7. Space, Density and Urban Form

    OpenAIRE

    Berghauser Pont, M.Y.; Haupt, P.A.

    2009-01-01

    The concentration of humans – in some cases judged as too high, in others not high enough – and the problems connected to this, have resulted in discussions on density. Prior to the 20th century, density in European cities was merely an outcome of complex circumstances. During the second half of the 19th century, high densities in industrializing cities were argued to be one of the major causes of fires, diseases and social turmoil. In this period, density was introduced as a tool to analyse ...

  8. Regulating Competing Supramolecular Interactions Using Ligand Concentration.

    Science.gov (United States)

    Teunissen, Abraham J P; Paffen, Tim F E; Ercolani, Gianfranco; de Greef, Tom F A; Meijer, E W

    2016-06-01

    The complexity of biomolecular systems inevitably leads to a degree of competition between the noncovalent interactions involved. However, the outcome of biological processes is generally very well-defined often due to the competition of these interactions. In contrast, specificity in synthetic supramolecular systems is usually based on the presence of a minimum set of alternative assembly pathways. While the latter might simplify the system, it prevents the selection of specific structures and thereby limits the adaptivity of the system. Therefore, artificial systems containing competing interactions are vital to stimulate the development of more adaptive and lifelike synthetic systems. Here, we present a detailed study on the self-assembly behavior of a C2v-symmetrical tritopic molecule, functionalized with three self-complementary ureidopyrimidinone (UPy) motifs. Due to a shorter linker connecting one of these UPys, two types of cycles with different stabilities can be formed, which subsequently dimerize intermolecularly via the third UPy. The UPy complementary 2,7-diamido-1,8-naphthyridine (NaPy) motif was gradually added to this mixture in order to examine its effect on the cycle distribution. As a result of the C2v-symmetry of the tritopic UPy, together with small differences in binding strength, the cycle ratio can be regulated by altering the concentration of NaPy. We show that this ratio can be increased to an extent where one type of cycle is formed almost exclusively. PMID:27163942

  9. CERAMIC WASTE FORM DATA PACKAGE

    Energy Technology Data Exchange (ETDEWEB)

    Amoroso, J.; Marra, J.

    2014-06-13

    The purpose of this data package is to provide information about simulated crystalline waste forms that can be used to select an appropriate composition for a Cold Crucible Induction Melter (CCIM) proof of principle demonstration. Melt processing, viscosity, electrical conductivity, and thermal analysis information was collected to assess the ability of two potential candidate ceramic compositions to be processed in the Idaho National Laboratory (INL) CCIM and to guide processing parameters for the CCIM operation. Given uncertainties in the CCIM capabilities to reach certain temperatures throughout the system, one waste form designated 'Fe-MP' was designed towards enabling processing and another, designated 'CAF-5%TM-MP' was designed towards optimized microstructure. Melt processing studies confirmed both compositions could be poured from a crucible at 1600{degrees}C although the CAF-5%TM-MP composition froze before pouring was complete due to rapid crystallization (upon cooling). X-ray diffraction measurements confirmed the crystalline nature and phase assemblages of the compositions. The kinetics of melting and crystallization appeared to vary significantly between the compositions. Impedance spectroscopy results indicated the electrical conductivity is acceptable with respect to processing in the CCIM. The success of processing either ceramic composition will depend on the thermal profiles throughout the CCIM. In particular, the working temperature of the pour spout relative to the bulk melter which can approach 1700{degrees}C. The Fe-MP composition is recommended to demonstrate proof of principle for crystalline simulated waste forms considering the current configuration of INL's CCIM. If proposed modifications to the CCIM can maintain a nominal temperature of 1600{degrees}C throughout the melter, drain, and pour spout, then the CAF-5%TM-MP composition should be considered for a proof of principle demonstration.

  10. Development of unconventional forming methods

    Directory of Open Access Journals (Sweden)

    S. Rusz

    2012-10-01

    Full Text Available Purpose: Paper presents results of progress ECAP processing method for UFG structure reached (gained.The properties and microstructure are influenced by technological factors during application ECAP method.Design/methodology/approach: Summary of methods studied on Department of technology at Machining faculty of VŠB-TU Ostrava through of co-operation with Institute of Engineering Materials and Biomaterials, Silesian University of Technology is presented.Findings: Achievement of ultra-fine grained structure in initial material leads to substantial increase of plasticity and makes it possible to form materials in conditions of „superplastic state“. Achievement of the required structure depends namely of the tool geometry, number of passes through the matrix, obtained deformation magnitude and strain rate, process temperature and lubrication conditions. High deformation at comparatively low homologous temperatures is an efficient method of production of ultra-fine grained solid materials.The new technologies, which use severe plastic deformation, comprise namely these techniques: High Pressure Torsion, Equal Channel Angular Pressing = ECAP, Cyclic Channel Die Compression = CCDC, Cyclic Extrusion Compression = CEC, Continuous Extrusion Forming = CONFORM, Accumulative Roll Bonding, Constrained Groove Pressing.Research limitations/implications: Achieved hardness and microstructure characteristics will be determined by new research.Practical implications: The results may be utilized for a relation between structure and properties of the investigated materials in future process of manufacturing.Originality/value: These results contribute to complex evaluation of properties new metals after application unconventional forming methods. The results of this paper are determined for research workers deal by the process severe plastic deformation.

  11. [Adult form of Pompe disease].

    Science.gov (United States)

    Ziółkowska-Graca, Bozena; Kania, Aleksander; Zwolińska, Grazyna; Nizankowska-Mogilnicka, Ewa

    2008-01-01

    Pompe disease (glycogen-storage disease type II) is an autosomal recessive disorder caused by a deficiency of lysosomal acid alpha-glucosidase (GAA), leading to the accumulation of glycogen in the lysosomes primarily in muscle cells. In the adult form of the disease, proximal muscle weakness is noted and muscle volume is decreased. The infantile form is usually fatal. In the adult form of the disease the prognosis is relatively good. Muscle weakness may, however, interfere with normal daily activities, and respiratory insufficiency may be associated with obstructive sleep apnea. Death usually results from respiratory failure. Effective specific treatment is not available. Enzyme replacement therapy with recombinant human GAA (rh-GAA) still remains a research area. We report the case of a 24-year-old student admitted to the Department of Pulmonary Diseases because of severe respiratory insufficiency. Clinical symptoms such as dyspnea, muscular weakness and increased daytime sleepiness had been progressing for 2 years. Clinical examination and increased blood levels of CK suggested muscle pathology. Histopathological analysis of muscle biopsy, performed under electron microscope, confirmed the presence of vacuoles containing glycogen. Specific enzymatic activity of alpha-glucosidase was analyzed confirming Pompe disease. The only effective method to treat respiratory insufficiency was bi-level positive pressure ventilation. Respiratory rehabilitation was instituted and is still continued by the patient at home. A high-protein, low-sugar diet was proposed for the patient. Because of poliglobulia low molecular weight heparin was prescribed. The patient is eligible for experimental replacement therapy with rh-GAA. PMID:19003770

  12. On the flexural vibration of an elastic plate carrying a concentrated mass

    International Nuclear Information System (INIS)

    The dynamic response of an elastic plate carrying a concentrated mass is analysed. Despite the presence of a singular mass distribtion function, a rigorous analysis leading to a closed-form solution in the form of an infinite series has been made. By developing Green's function for the associated partial differential equation, any form of dynamic excitation is easily considered. (orig.)

  13. On the flexural vibration of an elastic plate carrying a concentrated mass

    Energy Technology Data Exchange (ETDEWEB)

    Sadiku, S. (Federal Univ. of Technology, Minna (Nigeria). Dept. of Civil Engineering)

    1989-12-01

    The dynamic response of an elastic plate carrying a concentrated mass is analysed. Despite the presence of a singular mass distribtion function, a rigorous analysis leading to a closed-form solution in the form of an infinite series has been made. By developing Green's function for the associated partial differential equation, any form of dynamic excitation is easily considered. (orig.).

  14. Capillary flows with forming interfaces

    CERN Document Server

    Shikhmurzaev, Yulii D

    2007-01-01

    PREFACEINTRODUCTION Free-surface flows in nature and industryScope of the bookFUNDAMENTALS OF FLUID MECHANICS Main concepts Governing equations Elements of thermodynamics Classical boundary conditions Physically meaningful solutions and paradoxes of modelingMOVING CONTACT LINES: AN OVERVIEW Essence of the problem Experimental observations Molecular dynamics simulations Review of theoriesThe key to the moving contact-line problemBOUNDARY CONDITIONS ON FORMING INTERFACES Modeling of interfacesConservation lawsLiquid-gas and liquid-solid interfacesLiquid-liquid interfaces SummaryOpen questions an

  15. Instructions & Forms for Authors

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Journal of Materials Sciences & Technology is a monthly journal for the rapid dissemination of new, impor- tant results in material and related fields. Submission Electronic files of MS Word and PDF are acceptable. Please visit http://www.jmst.org and submit online. Submission of a manuscript must be the original work of the author(s) and has not been published elsewhere or under consideration for another publication, or a substantially similar form in any language. Authors are encouraged to recommend three to five individuals (including their research fields, e-mail, phone numbers and addresses) who are qualified to serve as referees for their paper.

  16. Two forms of reactive arthritis?

    OpenAIRE

    Toivanen, P; Toivanen, A

    1999-01-01

    Inflammatory arthritides developing after a distant infection have so far been called reactive or postinfectious, quite often depending on the microbial trigger and/or HLA-B27 status of the patient. For clarity, it is proposed that they all should be called reactive arthritis, which, according to the trigger, occurs as an HLA-B27 associated or non-associated form. In addition to the causative agents and HLA-B27, these two categories are also distinguished by other characteristics. Most import...

  17. Screening three-form fields

    CERN Document Server

    Barreiro, Tiago; Nunes, Nelson J

    2016-01-01

    Screening mechanisms for a three-form field around a dense source such as the Sun are investigated. Working with the dual vector, we can obtain a thin-shell where field interactions are short range. The field outside the source adopts the configuration of a dipole which is a manifestly distinct behaviour from the one obtained with a scalar field or even a previously proposed vector field model. We identify the region of parameter space where this model satisfies present solar system tests.

  18. Baryon Form Factors at Threshold

    Energy Technology Data Exchange (ETDEWEB)

    Baldini Ferroli, Rinaldo [Museo Storico della Fisica e Centro Studi e Ricerche ' E. Fermi' , Rome (Italy); INFN, Laboratori Nazionali di Frascati, Frascati (Italy); Pacetti, Simone [INFN and Dipartimento di Fisica, Universita di Perugia, Perugia (Italy)

    2012-04-15

    An extensive study of the e{sup +}e{sup -}{yields}pp{sup Macron }BABAR cross section data is presented. Two unexpected outcomes have been found: the modulus of the proton form factor is normalized to one at threshold, i.e.: |G{sup p}(4M{sub p}{sup 2})|=1, as a pointlike fermion, and the resummation factor in the Sommerfeld formula is not needed. Other e{sup +}e{sup -} {yields} baryon-antibaryon cross sections show a similar behavior near threshold.

  19. Numerical Simulation of Peen Forming

    Institute of Scientific and Technical Information of China (English)

    Kang Xiaoming; Ma Zeen; Gu Lin; Chen ming

    2004-01-01

    Peen forming is the most important process for the manufacturing of integral wing skin panels. In order to determine peening parameters, an equivalent deformation theory was proposed in which peening parameters are transformed into equivalent nodal forces. In this study, a linear elastic shell finite element method is adopted. Other related problems such as wing skin panel modeling and peening scheme analysis were also outlined. The method has been applied to manufacturing panels of a certain Chinese aircraft and was proved to be effective in reducing peening experimental tests and improving products quality.

  20. Theoretical mechanics for sixth forms

    CERN Document Server

    Plumpton, C

    1971-01-01

    Theoretical Mechanics for Sixth Forms, Second Edition is a 14-chapter book that begins by elucidating the nature of theoretical mechanics. The book then describes the statics of a particle in illustration of the techniques of handling vector quantities. Subsequent chapters focus on the principle of moments, parallel forces and centers of gravity; and the application of Newton's second law to the dynamics of a particle and the ideas of work and energy, impulse and momentum, and power. The concept of friction is also explained. This volume concludes with chapters concerning motion in a circle an

  1. Terra Firma-forme Dermatosis

    Directory of Open Access Journals (Sweden)

    Anagha Ramesh Babu

    2013-01-01

    Full Text Available Terra firma-forme dermatosis is a cutaneous discoloration. ‘Dirty’ brown grey cutaneous patches and plaques that can be rid off by forceful swabbing with alcohol pads characterize it. The pathogenesis has been attributed to abnormal and delayed keratinization. It poses no medical threat. A 40-year-old male patient presented to the Department of Dermatology with a 2-3 month history of persistent pigmented patches on both upper arms. The lesions were not associated with itching or burning sensation. He gives no history of exacerbation on exposure to the sun.

  2. Strange chiral nucleon form factors

    CERN Document Server

    Hemmert, T R; Meißner, Ulf G; Hemmert, Thomas R.; Kubis, Bastian; Meissner, Ulf-G.

    1999-01-01

    We investigate the strange electric and magnetic form factors of the nucleon in the framework of heavy baryon chiral perturbation theory to third order in the chiral expansion. All counterterms can be fixed from data. In particular, the two unknown singlet couplings can be deduced from the parity-violating electron scattering experiments performed by the SAMPLE and the HAPPEX collaborations. Within the given uncertainties, our analysis leads to a small and positive electric strangeness radius, $ = (0.05 \\pm 0.16) fm^2$. We also deduce the consequences for the upcoming MAMI A4 experiment.

  3. Forms of creativity in translation

    Directory of Open Access Journals (Sweden)

    Lucia V Aranda

    2009-12-01

    Full Text Available http://dx.doi.org/10.5007/2175-7968.2009v1n23p23This paper explores the creative constructs utilized by translators in the reformulation of texts. As translation studies realigns the definition of translation vis-à-vis the original, a number of factors inform translations: the agency and subjectivity of the translator, as well as questions of form, and the more obvious social factors. This discussion addresses the articulation of creativity as a response to specific cases and repositions translation as part of a greater creative project.

  4. On Quasi-Modular Forms, Almost Holomorphic Modular Forms, and the Vector-Valued Modular Forms of Shimura

    OpenAIRE

    Zemel, Shaul

    2013-01-01

    We extend the relation between quasi-modular forms and modular forms to a wider class of functions. We then relate both forms to vector-valued modular forms with symmetric power representations, and prove a general structure theorem for these vector-valued forms.

  5. Citalopram concentrations in samples from autopsies and living persons

    DEFF Research Database (Denmark)

    Worm, Karen; Dragsholt, Claus; Simonsen, Kirsten Wiese;

    1998-01-01

    Retskemi,Citalopram,fatal concentrations,toxic concentrations,therapeutic concentrations,metabolites......Retskemi,Citalopram,fatal concentrations,toxic concentrations,therapeutic concentrations,metabolites...

  6. AMERICAN QUARTER HORSES’ BEHAVIORAL FORMS

    Directory of Open Access Journals (Sweden)

    Iryna Olexandrivna Suprun

    2016-02-01

    Full Text Available The review of basic literary sources is made out of behavior of horse. On the basis of the field researches (visual supervisions after three different aged groups of mares it is built ethograms. An ethogram of behavioral forms among mares was developed. They represent the different forms of mares’ behavior in a dynamics. The reaction of mares of the different age-related and physiology groups on appearance of extraneous objects on a pasture, their activity, hierarchy, socialization is analyzed in groups. Several main studies on equines were reviewed in ethogram. Four objects were placed into the pasture with the mares and foals including a mat, cone, halter, and mounting block. Initial interest of mares in objects was high. Herd mentality highly evident. When one horse spooked at object the whole herd followed. After 5 minutes, majority of mares and foals lose interest in objects. The major general behavior categories observed include: locomotion, comfort, and harem social. Dominance was demonstrated while looking at the objects. Dominance was also demonstrated when a mare wanted to be in a specific place or play with a specific toy, she would pin her ears back, bite, or kick at the other mare. 

  7. Gravity, light and plant form.

    Science.gov (United States)

    Hangarter, R P

    1997-06-01

    Plants have evolved highly sensitive and selective mechanisms that detect and respond to various aspects of their environment. As a plant develops, it integrates the environmental information perceived by all of its sensory systems and adapts its growth to the prevailing environmental conditions. Light is of critical importance because plants depend on it for energy and, thus, survival. The quantity, quality and direction of light are perceived by several different photosensory systems that together regulate nearly all stages of plant development, presumably in order to maintain photosynthetic efficiency. Gravity provides an almost constant stimulus that is the source of critical spatial information about its surroundings and provides important cues for orientating plant growth. Gravity plays a particularly important role during the early stages of seedling growth by stimulating a negative gravitropic response in the primary shoot that orientates it towards the source of light, and a positive gravitropic response in the primary root that causes it to grow down into the soil, providing support and nutrient acquisition. Gravity also influences plant form during later stages of development through its effect on lateral organs and supporting structures. Thus, the final form of a plant depends on the cumulative effects of light, gravity and other environmental sensory inputs on endogenous developmental programs. This article is focused on developmental interactions modulated by light and gravity.

  8. Friction-formed liquid droplets

    Energy Technology Data Exchange (ETDEWEB)

    Lockwood, A J; Inkson, B J [NanoLAB Centre, Department of Materials Science and Engineering, University of Sheffield, Sheffield S1 3JD (United Kingdom); Anantheshwara, K; Bobji, M S, E-mail: a.lockwood@sheffield.ac.uk, E-mail: beverley.inkson@sheffield.ac.uk [Department of Mechanical Engineering, Indian Institute of Science (IISc), Bangalore 560012 (India)

    2011-03-11

    The formation of nanoscale liquid droplets by friction of a solid is observed in real-time. This is achieved using a newly developed in situ transmission electron microscope (TEM) triboprobe capable of applying multiple reciprocating wear cycles to a nanoscale surface. Dynamical imaging of the nanoscale cyclic rubbing of a focused-ion-beam (FIB) processed Al alloy by diamond shows that the generation of nanoscale wear particles is followed by a phase separation to form liquid Ga nanodroplets and liquid bridges. The transformation of a two-body system to a four-body solid-liquid system within the reciprocating wear track significantly alters the local dynamical friction and wear processes. Moving liquid bridges are observed in situ to play a key role at the sliding nanocontact, interacting strongly with the highly mobile nanoparticle debris. In situ imaging demonstrates that both static and moving liquid droplets exhibit asymmetric menisci due to nanoscale surface roughness. Nanodroplet kinetics are furthermore dependent on local frictional temperature, with solid-like surface nanofilaments forming on cooling. TEM nanotribology opens up new avenues for the real-time quantification of cyclic friction, wear and dynamic solid-liquid nanomechanics, which will have widespread applications in many areas of nanoscience and nanotechnology.

  9. Friction-formed liquid droplets

    Science.gov (United States)

    Lockwood, A. J.; Anantheshwara, K.; Bobji, M. S.; Inkson, B. J.

    2011-03-01

    The formation of nanoscale liquid droplets by friction of a solid is observed in real-time. This is achieved using a newly developed in situ transmission electron microscope (TEM) triboprobe capable of applying multiple reciprocating wear cycles to a nanoscale surface. Dynamical imaging of the nanoscale cyclic rubbing of a focused-ion-beam (FIB) processed Al alloy by diamond shows that the generation of nanoscale wear particles is followed by a phase separation to form liquid Ga nanodroplets and liquid bridges. The transformation of a two-body system to a four-body solid-liquid system within the reciprocating wear track significantly alters the local dynamical friction and wear processes. Moving liquid bridges are observed in situ to play a key role at the sliding nanocontact, interacting strongly with the highly mobile nanoparticle debris. In situ imaging demonstrates that both static and moving liquid droplets exhibit asymmetric menisci due to nanoscale surface roughness. Nanodroplet kinetics are furthermore dependent on local frictional temperature, with solid-like surface nanofilaments forming on cooling. TEM nanotribology opens up new avenues for the real-time quantification of cyclic friction, wear and dynamic solid-liquid nanomechanics, which will have widespread applications in many areas of nanoscience and nanotechnology.

  10. CR-Submanifolds of Generalized -Space Forms

    OpenAIRE

    Mahmood Jaafari Matehkolaee

    2013-01-01

    We study sectional curvature, Ricci tensor, and scalar curvature of submanifolds of generalized -space forms. Then we give an upper bound for foliate -horizontal (and vertical) CR-submanifold of a generalized -space form and an upper bound for minimal -horizontal (and vertical) CR-submanifold of a generalized -space form. Finally, we give the same results for special cases of generalized -space forms such as -space forms, generalized Sasakian space forms, Sasakian space forms, Kenmotsu space ...

  11. Rapid and selective concentration of microparticles in an optoelectrofluidic platform.

    Science.gov (United States)

    Hwang, Hyundoo; Park, Je-Kyun

    2009-01-21

    We demonstrate rapid manipulation and selective concentration of microparticles using AC electrokinetics such as dielectrophoresis (DEP) and AC electro-osmosis (ACEO) in an optoelectrofluidic platform based on a liquid crystal display (LCD). When 10 V bias at 10 kHz was applied to the optoelectrofluidic device, only the 1 microm-diameter polystyrene particles were concentrated into the projected LCD image patterns and closely packed, forming the crystalline structure by ACEO flow, while the 6 microm-diameter particles were repelled by negative DEP forces. We have characterized this frequency-dependency of the optoelectrofluidic particle behavior according to the particle diameter. On the basis of these results, we can rapidly concentrate the 1 microm-diameter particles and separate them from the 6 microm particles, by applying an AC signal of 10 kHz frequency. This novel technique can be applied to rapidly concentrate, separate and pattern micro-/nanoparticles in many biological and chemical applications. PMID:19107274

  12. Capillarity ion concentration polarization as spontaneous desalting mechanism.

    Science.gov (United States)

    Park, Sungmin; Jung, Yeonsu; Son, Seok Young; Cho, Inhee; Cho, Youngrok; Lee, Hyomin; Kim, Ho-Young; Kim, Sung Jae

    2016-04-01

    To overcome a world-wide water shortage problem, numerous desalination methods have been developed with state-of-the-art power efficiency. Here we propose a spontaneous desalting mechanism referred to as the capillarity ion concentration polarization. An ion-depletion zone is spontaneously formed near a nanoporous material by the permselective ion transportation driven by the capillarity of the material, in contrast to electrokinetic ion concentration polarization which achieves the same ion-depletion zone by an external d.c. bias. This capillarity ion concentration polarization device is shown to be capable of desalting an ambient electrolyte more than 90% without any external electrical power sources. Theoretical analysis for both static and transient conditions are conducted to characterize this phenomenon. These results indicate that the capillarity ion concentration polarization system can offer unique and economical approaches for a power-free water purification system.

  13. Capillarity ion concentration polarization as spontaneous desalting mechanism

    Science.gov (United States)

    Park, Sungmin; Jung, Yeonsu; Son, Seok Young; Cho, Inhee; Cho, Youngrok; Lee, Hyomin; Kim, Ho-Young; Kim, Sung Jae

    2016-04-01

    To overcome a world-wide water shortage problem, numerous desalination methods have been developed with state-of-the-art power efficiency. Here we propose a spontaneous desalting mechanism referred to as the capillarity ion concentration polarization. An ion-depletion zone is spontaneously formed near a nanoporous material by the permselective ion transportation driven by the capillarity of the material, in contrast to electrokinetic ion concentration polarization which achieves the same ion-depletion zone by an external d.c. bias. This capillarity ion concentration polarization device is shown to be capable of desalting an ambient electrolyte more than 90% without any external electrical power sources. Theoretical analysis for both static and transient conditions are conducted to characterize this phenomenon. These results indicate that the capillarity ion concentration polarization system can offer unique and economical approaches for a power-free water purification system.

  14. STUDIES ON CRITICAL CONCENTRATION OF LIQUID CRYSTALLINE ETHYLCELLULOSE

    Institute of Scientific and Technical Information of China (English)

    DONG Yanming; ZHANG Shiying

    1996-01-01

    Critical concentrations of lyotropic liquid crystalline ethylcellulose in more than ten cal concentration Ccrit of forming liquid crystal phase decreased with increasing solubility parameter δ of solvent until approaching the δ of polymer. Although the alcohols used as solvents had the same variation rule, the critical concentration values of their solutions were much higher, due to their excessive large hydrogen bond component of δ. The experiments of using mixed solvents which showed good linear relation between Ccrit and δ also proved this rule. A technique of Transmission Optical Analysis was first used to estimate the concentration dependence of critical phase transition temperature Tcrit of EC, and a T-C phase diagram could be drawn.

  15. Accumulation of formamide in hydrothermal pores to form prebiotic nucleobases.

    Science.gov (United States)

    Niether, Doreen; Afanasenkau, Dzmitry; Dhont, Jan K G; Wiegand, Simone

    2016-04-19

    Formamide is one of the important compounds from which prebiotic molecules can be synthesized, provided that its concentration is sufficiently high. For nucleotides and short DNA strands, it has been shown that a high degree of accumulation in hydrothermal pores occurs, so that temperature gradients might play a role in the origin of life [Baaske P, et al. (2007)Proc Natl Acad Sci USA104(22):9346-9351]. We show that the same combination of thermophoresis and convection in hydrothermal pores leads to accumulation of formamide up to concentrations where nucleobases are formed. The thermophoretic properties of aqueous formamide solutions are studied by means of Infrared Thermal Diffusion Forced Rayleigh Scattering. These data are used in numerical finite element calculations in hydrothermal pores for various initial concentrations, ambient temperatures, and pore sizes. The high degree of formamide accumulation is due to an unusual temperature and concentration dependence of the thermophoretic behavior of formamide. The accumulation fold in part of the pores increases strongly with increasing aspect ratio of the pores, and saturates to highly concentrated aqueous formamide solutions of ∼85 wt% at large aspect ratios. Time-dependent studies show that these high concentrations are reached after 45-90 d, starting with an initial formamide weight fraction of[Formula: see text]wt % that is typical for concentrations in shallow lakes on early Earth. PMID:27044100

  16. Accumulation of formamide in hydrothermal pores to form prebiotic nucleobases

    Science.gov (United States)

    Niether, Doreen; Afanasenkau, Dzmitry; Dhont, Jan K. G.

    2016-04-01

    Formamide is one of the important compounds from which prebiotic molecules can be synthesized, provided that its concentration is sufficiently high. For nucleotides and short DNA strands, it has been shown that a high degree of accumulation in hydrothermal pores occurs, so that temperature gradients might play a role in the origin of life [Baaske P, et al. (2007) Proc Natl Acad Sci USA 104(22):9346-9351]. We show that the same combination of thermophoresis and convection in hydrothermal pores leads to accumulation of formamide up to concentrations where nucleobases are formed. The thermophoretic properties of aqueous formamide solutions are studied by means of Infrared Thermal Diffusion Forced Rayleigh Scattering. These data are used in numerical finite element calculations in hydrothermal pores for various initial concentrations, ambient temperatures, and pore sizes. The high degree of formamide accumulation is due to an unusual temperature and concentration dependence of the thermophoretic behavior of formamide. The accumulation fold in part of the pores increases strongly with increasing aspect ratio of the pores, and saturates to highly concentrated aqueous formamide solutions of ˜85 wt% at large aspect ratios. Time-dependent studies show that these high concentrations are reached after 45-90 d, starting with an initial formamide weight fraction of 10-310-3 wt % that is typical for concentrations in shallow lakes on early Earth.

  17. Technology Roadmaps: Concentrating Solar Power

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-07-01

    The emerging technology known as concentrating solar power, or CSP, holds much promise for countries with plenty of sunshine and clear skies. Its electrical output matches well the shifting daily demand for electricity in places where airconditioning systems are spreading. When backed up by thermal storage facilities and combustible fuel, it offers utilities electricity that can be dispatched when required, enabling it to be used for base, shoulder and peak loads. Within about one to two decades, it will be able to compete with coal plants that emit high levels of CO2. The sunniest regions, such as North Africa, may be able to export surplus solar electricity to neighbouring regions, such as Europe, where demand for electricity from renewable sources is strong. In the medium-to-longer term, concentrating solar facilities can also produce hydrogen, which can be blended with natural gas, and provide low-carbon liquid fuels for transport and other end-use sectors. For CSP to claim its share of the coming energy revolution, concerted action is required over the next ten years by scientists, industry, governments, financing institutions and the public. This roadmap is intended to help drive these indispensable developments.

  18. Concentrated photovoltaics, a case study

    Directory of Open Access Journals (Sweden)

    Antonini Piergiorgio

    2014-01-01

    Full Text Available Concentrated Photovoltaics (CPV, once a niche technology, has now reached the maturity and reliability for large scale power generation. Especially in regions where temperatures are very high, the use of high efficiency triple junction solar cells with concentrating optics allows stable energy yield. Thus CPV can be seen as complementary and not in concurrence with silicon photovoltaics. The state of the art, the advantages and limitations of this technology will be shown. Among the main advantages of CPV is the possibility of a much higher energy supply, when compared to silicon photovoltaics, both comparing CPV and silicon with same area or the same installed power. The use of recycled and recyclable materials allows a more environmentally friendly production. The possibility to couple CPV with desalination facilities, energy storage will be analysed. As an example a case study of a CPV installation in Northern Italy is discussed. Here the use of mature technologies, derived from automotive and lighting sectors resulted in a simple and efficient module.

  19. Forming impressions from incongruent traits.

    Science.gov (United States)

    Casselden, P A; Hampson, S E

    1990-08-01

    The factors that affect the ease with which impressions are formed from incongruent trait pairs are investigated. In Experiments 1 and 2, trait pairs that were both descriptively and evaluatively congruent, as well as ones that were only evaluatively congruent, were found to be more imaginable and to be perceived as more frequently co-occurring than incongruent trait pairs. In Experiment 3, response latency provided a converging measure of ease of imaginability. Experiment 4 examined written descriptions of targets described by these trait pairs, and found more attempts to integrate the congruent than the incongruent pairs. These findings are discussed in terms of the relation between laypersons' impressions of personality and formal personality assessment.

  20. ACUTE PANCREATITIS - THE SEVERE FORM

    Directory of Open Access Journals (Sweden)

    Ioana Grigoras

    2005-01-01

    Full Text Available Acute pancreatitis is an acute inflammatory disease. Frequently it is a challenging condition for the surgeon and for the intensive care physician, taking into account that etiology is sometimes obscure, the pathophysiology is complex and incompletely understood, the timing of surgical treatment is still under debate and the general treatment is mostly supportive. The incidence is about 30 – 50 / 100.000 / year. In 80% of cases the disease is associated with interstitial edema, mild infiltration with inflammatory cells and intra- or peripancreatic fat necrosis. Evolution is benign and self-limited with proper treatment. The severe form occurs less frequent (15 - 20%, results in long lasting hospitalization and is associated with high mortality (30 - 40%, due to infected necrosis and multiple organ failure. Alcoholism and biliary disease account for 80% of cases. Rare etiologies of disease include metabolic factors (hypercalcemia, hyperlipoproteinemia, drug ingestion, obstructive factors (abdominal tumors, trauma, endoscopic retrograde cholecistopancreatography, and s.o., infections (viral, parasitic and hemodynamic factors. Postoperative pancreatitis is a complication after major abdominal surgery (abdominal aorta aneurism repair, extensive upper abdominal surgery, hepatic or cardiac transplant, so.. The common pathophysiological mechanism is pancreatic hypoperfusion. Acute pancreatitis is not a stable disease, being characterized by time-dependent stages with specific morphologic and clinical patterns. The terminology used to designate these stages is stated in the Ulm classification. Since the consensus Conference in Atlanta (1992 the severe form of acute pancreatitis is defined by the presence of organ dysfunction/failure or by the presence of local complications. The initiating event is the premature zymogene activation and the impairment of the exocytosis process with local consequences (ongoing tissue necrosis and general consequences

  1. Fabrication Aware Form-finding

    DEFF Research Database (Denmark)

    Egholm Pedersen, Ole; Larsen, Niels Martin; Pigram, Dave;

    2014-01-01

    This paper describes a design and construction method that combines two distinct material systems with fabrication aware form-finding and file-to-factory workflows. The method enables the fluent creation of complex materially efficient structures comprising high populations of geometrically unique...... parts. The first material system employs a novel rotated joint design to allow the structural tuning of quasi-reciprocal timber frame elements fabricated from multi-axis machined plywood sheet stock. The second em-loys discontinuous post-tensioning to assemble unique precast concrete components...... into load-bearing structures, significantly reducing or eliminating false work during as-embly. The method is tested with the construction of a research pavilion....

  2. Waste form development/test

    International Nuclear Information System (INIS)

    The main objective of this study is to investigate new solidification agents relative to their potential application to wastes generated by advanced high volume reduction technologies, e.g., incinerator ash, dry solids, and ion exchange resins. Candidate materials selected for the solidification of these wastes include a modified sulfur cement and low-density polyethylene, neither of which are currently employed commerically for the solidification of low-level waste (LLW). As both the modified sulfur cement and the polyethylene are thermoplastic materials, a heated screw type extruder is utilized in the production of waste form samples for testing and evaluation. In this regard, work is being conducted to determine the range of conditions under which these solidification agents can be satisfactorily applied to the specific LLW streams and to provide information relevant to operating parameters and process control

  3. Mycoplasmas: small but perfectly formed

    Directory of Open Access Journals (Sweden)

    Robin NICHOLAS

    2015-07-01

    Full Text Available Interest in mycoplasmas stems from their importance as serious animal and human pathogens, their frequent contamination of cell lines and, because of their small size, for their use as models of the minimal cell concept.They have traditionally been seen as highly host specific but this is being reviewed in view of recent detections of animal mycoplasmas in unlikely hosts including humans. Some highlights include:Mycoplasmas, containing as few as 450 genes, are the smallest free-living organisms on the planetThey were the first synthetically created life formsWhile the majority of mycoplasmas are harmless, the World Organisation for Animal Health (OIE have listed 4 mycoplasma diseases because of their serious socio-economic impacts10-15% of cell lines used for virus research are contaminated with mycoplasma Are they the real the causes of TSEs and other undiagnosed human conditions?

  4. The Textile Form of Sound

    DEFF Research Database (Denmark)

    Bendixen, Cecilie

    of sound. This issue is a part of a Ph.D. study at The Danish Design School in Copenhagen. Sound diffusion in architecture is a complex phenomenon. From the sound source the sound spreads in all directions as a sphere of wave fronts. When the sound is reflected from room boundaries or furniture, complex...... experiments were carried out. One experiment was done in a laboratory with a sound measure instrument and textiles arranged in different positions and shapes. Here the high energy spots were located. The other experiment is ongoing and is an investigation of how textiles can take the shape of the sound......Sound is a part of architecture, and sound is complex. Upon this, sound is invisible. How is it then possible to design visual objects that interact with the sound? This paper addresses the problem of how to get access to the complexity of sound and how to make textile material revealing the form...

  5. The Form of HWID Theory

    DEFF Research Database (Denmark)

    Clemmensen, Torkil

    2015-01-01

    The aim of activities within the Human-Computer Interaction (HCI) area named Human Work Interaction Design (HWID) is to establish relationships between empirical work-domain studies and recent developments in interaction design. Recent areas of research within HWID include design sketches for work......, usability in context, work analysis for HCI, and integration of work analysis and interaction design methods for pervasive and smart workplaces. Across these areas, the question emerges what form of theory may HWID research produce? The aim with this paper is to investigate the requirements of different...... research purposes to a common framework. We take the position that we should approach HWID with a lightweight, medium-level framework that is useful to guide the application of other theories to study the relation between work analysis and interaction design. We analyse the requirements to theory found...

  6. Forming impressions from incongruent traits.

    Science.gov (United States)

    Casselden, P A; Hampson, S E

    1990-08-01

    The factors that affect the ease with which impressions are formed from incongruent trait pairs are investigated. In Experiments 1 and 2, trait pairs that were both descriptively and evaluatively congruent, as well as ones that were only evaluatively congruent, were found to be more imaginable and to be perceived as more frequently co-occurring than incongruent trait pairs. In Experiment 3, response latency provided a converging measure of ease of imaginability. Experiment 4 examined written descriptions of targets described by these trait pairs, and found more attempts to integrate the congruent than the incongruent pairs. These findings are discussed in terms of the relation between laypersons' impressions of personality and formal personality assessment. PMID:2213498

  7. Simultaneous Assembly of Multiple Test Forms

    NARCIS (Netherlands)

    Linden, van der Wim J.; Adema, Jos J.

    1998-01-01

    An algorithm for the assembly of multiple test forms is proposed in which the multiple-form problem is reduced to a series of computationally less intensive two-form problems. At each step, one form is assembled to its true specifications; the other form is a dummy assembled only to maintain a balan

  8. 48 CFR 570.701 - Standard forms.

    Science.gov (United States)

    2010-10-01

    ... PROGRAMS ACQUIRING LEASEHOLD INTERESTS IN REAL PROPERTY Forms 570.701 Standard forms. Use Standard Form 2, U.S. Government Lease for Real Property, to award leases unless you use GSA Form 3626 (see 570.702). Delete the reference to the Standard Form 2-A in paragraph 7....

  9. 48 CFR 570.702 - GSA forms.

    Science.gov (United States)

    2010-10-01

    ... PROGRAMS ACQUIRING LEASEHOLD INTERESTS IN REAL PROPERTY Forms 570.702 GSA forms. (a) You may use GSA Form 3626, U.S. Government Lease for Real Property (Short Form), to award leases if you use the simplified leasing procedures in 570.2 or if you determine it advantageous to use. (b) You may use GSA Form...

  10. Tetracycline-resistant L-forms isolated from an antibiotic-susceptible strain of Listeria monocytogenes.

    OpenAIRE

    Schmitt-Slomska, J; Marmouset, M C; Louis, C.; Bally, R.; Starka, G; Madoff, S

    1982-01-01

    A tetracycline-susceptible strain of Listeria monocytogenes type 4b was converted to stable L-forms by penicillin. L-form variants resistant to tetracycline were then selected from a predominantly tetracycline-susceptible L-form population on plates containing penicillin and increasing concentrations of tetracycline. The origin of tetracycline-resistant L-forms from the parent Listeria strain was confirmed biochemically, by immunofluorescence, and by polyacrylamide gel electrophoresis. Scanni...

  11. Freeze concentration of lime juice

    Directory of Open Access Journals (Sweden)

    Ampawan Tansakul

    2008-11-01

    Full Text Available The main objective of this research was to study the effects of processing conditions, i.e. cooling medium temperature (-6, -12 and -18C and scraper blade rotational speed (50, 100 and 150 rpm on the freeze concentration of lime juice. The initial soluble solid content of lime juice was 7.6 Brix. Results showed that soluble solid content of lime juice increased as cooling medium temperature decreased while scraper blade rotational speed increased. It was also found that the processing condition with -18˚C cooling medium temperature and 150 rpm rotational speed of the scraper blade was the best among all studied conditions, although the loss of the soluble solids with ice crystals during ice separation was relatively high at 35%.

  12. Size and concentration controlled growth of porous gold nanofilm

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Renyun; Hummelgaard, Magnus; Olin, Haakan [Department of Natural Sciences, Engineering and Mathematics, Mid Sweden University, Sundsvall (Sweden)

    2012-03-15

    At an air/water interface, diffusion-limited aggregation (DLA) of gold nanoparticles can form porous gold thin films. This porous film roughly consists of a network of irregular nanowires. For this air-water system, external parameters like temperature are well studied, while the influence of internal parameters, e.g., the size and concentration of the nanoparticles, have not been studied in detail. Here, we report on the growth of porous gold nanofilms for different nanoparticle sizes and concentrations to get a relationship between the morphology of the films and the internal parameters. The gold nanoparticles were synthesized by reducing HAuCl{sub 4} using sodium citrate. Transmission electron microscopy (TEM) characterization showed a linear relation between the formed gold nanowires and the concentration of HAuCl{sub 4} if the concentration of sodium citrate is unchanged. A linear dependency was also found between the wire diameter and the gold nanoparticle concentration, and between the wire diameter and volume fraction of the nanoparticles. The electrical resistance of the films was measured, showing a linear relation between resistance and the inverse of the cross-sectional area of the nanowires. This study shows the relation between the morphology and resistance of the grown porous films and the controllable internal parameters that will be useful in further exploration of this thin-film growth method. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. Mechanism of Concentration Dependence of Water Diffusivity in Polyacrylate Gels

    Science.gov (United States)

    Mani, Sriramvignesh; Khabaz, Fardin; Khare, Rajesh

    Membrane based separation processes offer an energy efficient alternative to traditional distillation based separation processes. In this work, we focus on the molecular mechanisms underlying the process of separation of dilute ethanol-water mixture using polyacrylate gels as pervaporation membranes. The diffusivities of the components in swollen gels exhibit concentration dependence. We have used molecular dynamics (MD) simulations to study the correlation between the dynamics of solvent (water and ethanol) molecules, polymer dynamics and solvent structure in the swollen gel systems as a function of solvent concentration. Three different polyacrylate gels were studied: (1) poly n-butyl acrylate (PBA), (2) copolymer of butyl acrylate and 2-hydroxyethyl acrylate P(BA50-HEA50), and (3) poly 2-hydroxyethyl acrylate (PHEA). Simulation results show that solvent concentration has a significant effect on local structure of the solvent molecules and chain dynamics; these factors (local structure and chain dynamics), in turn, affect the diffusivity of these molecules. At low concentration, solvent molecules are well dispersed in the gel matrix and form hydrogen bonds with the polymer. Solvent mobility is correlated with polymer mobility in this configuration and consequently water and ethanol molecules exhibit slower dynamics, this effect is especially significant in PHEA gel. At high solvent concentration, water molecules form large clusters in the system accompanied by enhancement in mobility of both the gel network and the solvent molecules.

  14. Are There Various Forms of Lupus?

    Science.gov (United States)

    ... lupus Understanding lupus Are there various forms of lupus? Systemic Lupus Erythematosus Systemic lupus is the most common form ... and tissues at “ Lupus and the Body ”. Cutaneous Lupus Erythematosus This form of lupus is limited to ...

  15. 48 CFR 3053.303 - Agency forms.

    Science.gov (United States)

    2010-10-01

    ... section illustrates agency-specified forms. To access these forms go to: http://www.dhs.gov (under “Business, Acquisition Information”) or https://dhsonline.dhs.gov/portal/jhtml/general/forms.jhtml....

  16. Effect of protein concentration, pH, lactose content and pasteurization on thermal gelation of acid caprine whey protein concentrates.

    Science.gov (United States)

    Bordenave-Juchereau, Stéphanie; Almeida, Bruno; Piot, Jean-Marie; Sannier, Frédéric

    2005-02-01

    The influence of pH (4.5-6.5), sodium chloride content (125-375 mM), calcium chloride content (10-30 mM), protein concentration (70-90 g/l) and lactose content on the gel hardness of goat whey protein concentrate (GWPC) in relation to the origin of the acid whey (raw or pasteurized milk) was studied using a factorial design. Gels were obtained after heat treatment (90 degrees C, 30 min). Gel hardness was measured using texture analyser. Only protein concentration and pH were found to have a statistically significant effect on the gel hardness. An increase in the protein concentration resulted in an increase in the gel hardness. GWPC containing 800g/kg protein formed gels with a hardness maximum at the pHi, whereas GWPC containing 300 g/kg protein did not form true gels. Whey from pasteurized milk formed softer gels than whey from raw milk. A high lactose content (approximately 360 g/kg) also reduced the gelation performance of GWPC. PMID:15747729

  17. Toxicity Data to Determine Refrigerant Concentration Limits

    Energy Technology Data Exchange (ETDEWEB)

    Calm, James M.

    2000-09-30

    This report reviews toxicity data, identifies sources for them, and presents resulting exposure limits for refrigerants for consideration by qualified parties in developing safety guides, standards, codes, and regulations. It outlines a method to calculate an acute toxicity exposure limit (ATEL) and from it a recommended refrigerant concentration limit (RCL) for emergency exposures. The report focuses on acute toxicity with particular attention to lethality, cardiac sensitization, anesthetic and central nervous system effects, and other escape-impairing effects. It addresses R-11, R-12, R-22, R-23, R-113, R-114, R-116, R-123, R-124, R-125, R-134, R-134a, R-E134, R-141b, R-142b, R-143a, R-152a, R-218, R-227ea, R-236fa, R-245ca, R-245fa, R-290, R-500, R-502, R-600a, R-717, and R-744. It summarizes additional data for R-14, R-115, R-170 (ethane), R-C318, R-600 (n-butane), and R-1270 (propylene) to enable calculation of limits for blends incorporating them. The report summarizes the data a nd related safety information, including classifications and flammability data. It also presents a series of tables with proposed ATEL and RCL concentrations-in dimensionless form and the latter also in both metric (SI) and inch-pound (IP) units of measure-for both the cited refrigerants and 66 zerotropic and azeotropic blends. They include common refrigerants, such as R-404A, R-407C, R-410A, and R-507A, as well as others in commercial or developmental status. Appendices provide profiles for the cited single-compound refrigerants and for R-500 and R-502 as well as narrative toxicity summaries for common refrigerants. The report includes an extensive set of references.

  18. Effective viscoelastic behavior of particulate polymer composites at finite concentration

    Institute of Scientific and Technical Information of China (English)

    LI Dan; HU Geng-kai

    2007-01-01

    Polymeric materials usually present some viscoelastic behavior. To improve the mechanical behavior of these materials, ceramics materials are often filled into the polymeric materials in form of fiber or particle. A micromechanical model was proposed to estimate the overall viscoelastic behavior for particulate polymer composites, especially for high volume concentration of filled particles. The method is based on Laplace transform technique and an elastic model including two-particle interaction. The effective creep compliance and the stress and strainrelation at a constant loading rate are analyzed. The results show that the proposed method predicts a significant stiffer response than those based on Mori-Tanaka's method at high volume concentration of particles.

  19. Procedure for reducing hydrogen ion concentration in acidic anion eluate

    International Nuclear Information System (INIS)

    A procedure is suggested for reducing the concentration of hydrogen ions in the acidic anionic eluate formed during the separation of uranium. The procedure involves anex elution, precipitation, filtration, precipitate rinsing, and anex rinsing. The procedure is included in the uranium elution process and requires at least one ion exchanger column and at least one tank in the continuous or discontinuous mode. Sparing the neutralizing agent by reducing the hydrogen ion concentration in the acidic anionic eluate is a major asset of this procedure. (Z.S.). 1 fig

  20. Tritium concentration in unpolished rice

    International Nuclear Information System (INIS)

    Inoue and Iwakura recently reported that the specific activity ratio of organically-bound 3H to free water 3H in polished rice samples collected in Japan and China was lower than unity. Their paper was the first to report the systematic apparent elimination of 3H for incorporation to organically-bound form in samples collected from the general environment. To confirm their result, seven unpolished rice samples obtained just after harvesting were analyzed for 3H. The mean specific activity ratio of organically-bound 3H to free water 3H was found to be 0.57, somewhat lower than the data by Inoue and Iwakura. This small difference may be caused by the different sampling years and/or the possible replacement of free water by atmospheric water vapor after harvesting. (author)

  1. Miscellaneous Waste-Form FEPs

    Energy Technology Data Exchange (ETDEWEB)

    A. Schenker

    2000-12-08

    The US DOE must provide a reasonable assurance that the performance objectives for the Yucca Mountain Project (YMP) potential radioactive-waste repository can be achieved for a 10,000-year post-closure period. The guidance that mandates this direction is under the provisions of 10 CFR Part 63 and the US Department of Energy's ''Revised Interim Guidance Pending Issuance of New US Nuclear Regulatory Commission (NRC) Regulations (Revision 01, July 22, 1999), for Yucca Mountain, Nevada'' (Dyer 1999 and herein referred to as DOE's Interim Guidance). This assurance must be demonstrated in the form of a performance assessment that: (1) identifies the features, events, and processes (FEPs) that might affect the performance of the potential geologic repository; (2) examines the effects of such FEPs on the performance of the potential geologic repository; (3) estimates the expected annual dose to a specified receptor group; and (4) provides the technical basis for inclusion or exclusion of specific FEPs.

  2. Colloidal forming of metal/ceramic composites

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Herencia, A.J.; Gutierrez, C.A.; Millan, A.J.; Nieto, M.I.; Moreno, R. [Inst. de Ceramica y Vidrio, Madrid (Spain)

    2002-07-01

    Metal/Ceramic composites have very attractive properties as either structural or electronic materials. For certain applications, complex microstructures and shapes are required. Colloidal processing of ceramics has proved to provide better properties and allows to obtain near net complex shaped parts. However colloidal processing has not received a similar attention in powder metallurgy. This work deals with the colloidal approach to the forming of metallic and metal/ceramic composites in an aqueous medium. Rheological behavior of concentrated pure nickel, nickel/alumina and nickel/zirconia suspensions is studied and optimized for obtaining flat surfaces or near net shaped parts by tape casting and gel casting respectively. In each case the influence of the processing additives (acrylic binders for tape casting and carrageenans for gel casting) on the rheological behavior of the slurries is determined. Pure nickel and nickel/ceramic composites with different compositions have been prepared. Static and dynamic sintering studies were performed at different conditions in order to control the porosity and microstructure of the final bodies, which were characterized by optical microscopy. (orig.)

  3. Spectrophotometric estimation of roxithromycin in tablet dosage forms

    Directory of Open Access Journals (Sweden)

    Suhagia B

    2006-01-01

    Full Text Available A simple and sensitive spectrophotometric method has been developed for determination of roxithromycin in its pharmaceutical dosage forms. In the proposed method, roxithromycin is oxidized with potassium permanganate to liberate formaldehyde, which is determined in situ using acetyl acetone in the presence of ammonium acetate to give a yellow-coloured chromogen with absorption maxima at 412 nm. The method is found to be linear in the concentration range of 10-75 µg/ml with regression coefficient of 0.9987. No significant difference was found between the proposed method and the reported method when two-tailed t-tests are applied. Various reaction parameters, such as concentration of potassium permanganate and reagent, time required for oxidation and maximum colour intensity, were optimized. The method was validated and can be used successfully to assay roxithromycin in its pharmaceutical dosage form, viz, tablets.

  4. Determination of Azithromycin in pharmaceutical dosage forms by Spectrophotometric method

    Directory of Open Access Journals (Sweden)

    Suhagia B

    2006-01-01

    Full Text Available A simple and sensitive spectrophotometric method has been developed for determination of azithromycin in its pharmaceutical dosage forms. In the proposed method, azithromycin is oxidized with potassium permanganate to liberate formaldehyde, which is determined in situ using acetyl acetone, in the presence of ammonium acetate. A yellow coloured chromogen was obtained, having an absorption maxima at 412 nm. The method is found to be linear in the concentration range of 10-75 µg/ml, with regression coefficient of 0.9978. Various reaction parameters such as concentration of potassium permanganate and reagent, time required for oxidation, and maximum colour intensity were optimized. The method was validated, and can be used successfully to assay azithromycin in its pharmaceutical dosage forms viz. tablets, capsules, and injections.

  5. The distribution of Radon concentration in caves.

    OpenAIRE

    Cigna Arrigo A.

    2003-01-01

    Radon concentration in caves is known to vary within an extremely wide range. Here the distribution of the average values of radon concentration is examined and a power law describing is identified, i.e. radon concentration has a fractal dimension D=1.26. This fact means that concentrations are not grouped around a mean value, a characteristic common to many other phenomena.

  6. Chloride sublimation of gold-arsenic concentrates

    International Nuclear Information System (INIS)

    Present article is devoted to chloride sublimation of gold-arsenic concentrates. The results of studies of chloride sublimation of gold-arsenic comprising concentrates of Chore deposit of Tajikistan are considered. It is found that by application sodium chloride for gold-arsenic comprising concentrates it is possible to extract gold and silver from flotation concentrates.

  7. The concentration of retail in Poland

    Directory of Open Access Journals (Sweden)

    Michał Gazdecki

    2010-01-01

    Full Text Available The article discusses the processes of concentration taking place in retail in Poland. In spite of strong concentration processes, which took place after 2000, Poland still remains a country of dispersed retail structure. In the nearest years we can expect capital concentration (mainly takeovers in modern trade and contract concentration (for example, merchants’ societies in traditional trade.

  8. CFC concentrations in fresh groundwater in Latvia

    Science.gov (United States)

    Bikše, J.; DÄ`liĆa, A.; Babre, A.; RetiÄ·e, I.; Raga, B.; PÄ`rkone, E.

    2012-04-01

    One of the main issues in groundwater studies is groundwater age, also known as residence time. This is important for investigating the groundwater filtration rate and to solve variety issues of groundwater use, management and protection. Groundwater age studies in Latvia have been rare, and the latest study, which defined the new results of age of groundwater using CFC dating method, was during years 2002 - 2006 and it was carried out by Denmark and Greenland Geological Survey (GEUS) and the Latvian State Geological Survey as a joint study on the impact of agriculture on groundwater quality in Latvia. Within the project "Interdisciplinary research groups and model system for groundwater studies" (PUMA) the studies of groundwater age by CFCs and 3H methods is continued. The concentration of tritium will be determined in about 60 samples, but the CFC concentration is now analyzed in 39 samples because previous studies have shown that Latvian CFC method is appropriate for aquifers to an average depth of 30-50 m. CFCs concentrations were analyzed in the laboratory at GEUS after Busenberg and Plummer described method by gas chromatography equipped with an EDC detector. Interpretation of the results was carried out by laboratory expert Troels Laier. Samples are taken on both from the unconfined aquifer and the first confined aquifer, the sampling interval varies from 5-10 m up to 120-130 m for tritium analysis and up to 80 m depth for most CFC analysis except one sample that comes from 128 m depth. It is stated that most of determined groundwater from both - confined and unconfined aquifer - has residence time of 35-55 years. So far, the results suggest that groundwater movement is fairly rapid in places where fractured dolomite forms the aquifer as the water residence time at 60-70 m depth is only 35-55 years. On the other hand, the composition of overlying Quaternary deposits (clay, glacial till loam or sand, sand - gravel sediments) has great importance on variations

  9. Concentric Coplanar Capacitive Sensor System with Quantitative Model

    Science.gov (United States)

    Bowler, Nicola (Inventor); Chen, Tianming (Inventor)

    2014-01-01

    A concentric coplanar capacitive sensor includes a charged central disc forming a first electrode, an outer annular ring coplanar with and outer to the charged central disc, the outer annular ring forming a second electrode, and a gap between the charged central disc and the outer annular ring. The first electrode and the second electrode may be attached to an insulative film. A method provides for determining transcapacitance between the first electrode and the second electrode and using the transcapacitance in a model that accounts for a dielectric test piece to determine inversely the properties of the dielectric test piece.

  10. Spectrophotometric estimation of roxithromycin in tablet dosage forms

    OpenAIRE

    Suhagia B; Shah S; Rathod I; Patel H; Doshi K; Parmar V

    2006-01-01

    A simple and sensitive spectrophotometric method has been developed for determination of roxithromycin in its pharmaceutical dosage forms. In the proposed method, roxithromycin is oxidized with potassium permanganate to liberate formaldehyde, which is determined in situ using acetyl acetone in the presence of ammonium acetate to give a yellow-coloured chromogen with absorption maxima at 412 nm. The method is found to be linear in the concentration range of 10-75 µg/ml with regression...

  11. Determination of Azithromycin in pharmaceutical dosage forms by Spectrophotometric method

    OpenAIRE

    Suhagia B; Shah S; Rathod I; Patel H; Doshi K

    2006-01-01

    A simple and sensitive spectrophotometric method has been developed for determination of azithromycin in its pharmaceutical dosage forms. In the proposed method, azithromycin is oxidized with potassium permanganate to liberate formaldehyde, which is determined in situ using acetyl acetone, in the presence of ammonium acetate. A yellow coloured chromogen was obtained, having an absorption maxima at 412 nm. The method is found to be linear in the concentration range of 10-75 µg/ml, with ...

  12. Forms of zinc accumulated in the hyperaccumulator Arabidopsis halleri

    OpenAIRE

    Sarret, Geraldine; Saumitou-Laprade, Pierre; Bert, Valerie; Proux, Olivier; Hazemann, Jean-Louis; Traverse, Agnes; Marcus, Matthew,; Manceau, Alain

    2002-01-01

    The chemical forms of zinc (Zn) in the Zn-tolerant and hyperaccumulator Arabidopsis halleri and in the non-tolerant and nonaccumulator Arabidopsis lyrata subsp. petraea were determined at the molecular level by combining chemical analyses, extended x-ray absorption spectroscopy (EXAFS), synchrotron-based x-ray microfluorescence, and micro--EXAFS. Plants weree grown in hydroponics with various Zn concentrations, and A. halleri specimens growing naturally in a contaminated site were also collec...

  13. Uniform-droplet spray forming

    Energy Technology Data Exchange (ETDEWEB)

    Blue, C.A.; Sikka, V.K. [Oak Ridge National Lab., TN (United States); Chun, Jung-Hoon [Massachusetts Institute of Technology, Cambridge, MA (United States); Ando, T. [Tufts Univ., Medford, MA (United States)

    1997-04-01

    The uniform-droplet process is a new method of liquid-metal atomization that results in single droplets that can be used to produce mono-size powders or sprayed-on to substrates to produce near-net shapes with tailored microstructure. The mono-sized powder-production capability of the uniform-droplet process also has the potential of permitting engineered powder blends to produce components of controlled porosity. Metal and alloy powders are commercially produced by at least three different methods: gas atomization, water atomization, and rotating disk. All three methods produce powders of a broad range in size with a very small yield of fine powders with single-sized droplets that can be used to produce mono-size powders or sprayed-on substrates to produce near-net shapes with tailored microstructures. The economical analysis has shown the process to have the potential of reducing capital cost by 50% and operating cost by 37.5% when applied to powder making. For the spray-forming process, a 25% savings is expected in both the capital and operating costs. The project is jointly carried out at Massachusetts Institute of Technology (MIT), Tuffs University, and Oak Ridge National Laboratory (ORNL). Preliminary interactions with both finished parts and powder producers have shown a strong interest in the uniform-droplet process. Systematic studies are being conducted to optimize the process parameters, understand the solidification of droplets and spray deposits, and develop a uniform-droplet-system (UDS) apparatus appropriate for processing engineering alloys.

  14. Concentrating Solar Power. Technology Roadmap

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-10-15

    Concentrating solar power can contribute significantly to the world's energy supply. As shown in this roadmap, this decade is a critical window of opportunity during which CSP could become a competitive source of electrical power to meet peak and intermediate loads in the sunniest parts of the world. This roadmap identifies technology, economy and policy goals and milestones needed to support the development and deployment of CSP, as well as ongoing advanced research in CSF. It also sets out the need for governments to implement strong, balanced policies that favour rapid technological progress, cost reductions and expanded industrial manufacturing of CSP equipment to enable mass deployment. Importantly, this roadmap also establishes a foundation for greater international collaboration. The overall aim of this roadmap is to identify actions required - on the part of all stakeholders - to accelerate CSP deployment globally. Many countries, particularly in emerging regions, are only just beginning to develop CSP. Accordingly, milestone dates should be considered as indicative of urgency, rather than as absolutes. This roadmap is a work in progress. As global CSP efforts advance and an increasing number of CSP applications are developed, new data will provide the basis for updated analysis. The IEA will continue to track the evolution of CSP technology and its impacts on markets, the power sector and regulatory environments, and will update its analysis and set additional tasks and milestones as new learning comes to light.

  15. Gabapentin concentrations and postmortem distribution.

    Science.gov (United States)

    Hamm, Catherine E; Gary, Ray D; McIntyre, Iain M

    2016-05-01

    Gabapentin is a widely prescribed medication used primarily for the treatment of epilepsy and neuropathic pain. Gabapentin has a favorable adverse effect profile in therapeutic dosing with the most common reported effects being dizziness, fatigue, drowsiness, weight gain, and peripheral edema. Even with intentional self-poisonings, serious effects are generally rare. In this report, gabapentin analyses were performed on 30 postmortem cases that had peripheral blood, central blood and liver tissue. Overall the central to peripheral blood (C/P) ratio mean was 0.90±0.24 (mean±standard deviation), and a median of 0.97. The liver to peripheral blood (L/P) ratio mean was 0.68±0.26L/kg (mean±standard deviation), and a median of 0.65L/kg. An additional case, where both antemortem blood and postmortem peripheral blood specimens were available, revealed the same gabapentin concentration in both specimens. Taken together, the data presented suggests that gabapentin is unlikely to show postmortem redistribution.

  16. A Framework for Interactively Helpful Web Forms

    DEFF Research Database (Denmark)

    Bohøj, Morten; Bouvin, Niels Olof; Gammelmark, Henrik

    2012-01-01

    AdapForms is a framework for adaptive forms, consisting of a form definition language designating structure and constraints upon acceptable input, and a software architecture that continuously validates and adapts the form presented to the user. The validation is performed server-side, which...

  17. 48 CFR 245.7101 - Forms.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Forms. 245.7101 Section 245.7101 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE CONTRACT MANAGEMENT GOVERNMENT PROPERTY Plant Clearance Forms 245.7101 Forms. Use the forms...

  18. Siegel modular forms and their applications

    NARCIS (Netherlands)

    G. van der Geer

    2008-01-01

    These are the lecture notes of the lectures on Siegel modular forms at the Nordfjordeid Summer School on Modular Forms and their Applications. We give a survey of Siegel modular forms and explain the joint work with Carel Faber on vector-valued Siegel modular forms of genus 2 and present evidence fo

  19. E-Forms in E-Business

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The form-based application framework is proposed as a straightsolution for E-bu siness applications. A Rapid Application Development (RAD) tool FormNet is desi gned for developing complex enterprise network applications. Its main features and a comparison with Microsoft Windows Forms are presented in this paper. The tool can be also perfectly applied to the government form applications.

  20. Concentration of technetium-99 in marine environment

    Energy Technology Data Exchange (ETDEWEB)

    Hirano, Shigeki [National Inst. of Radiological Sciences, Nakaminato, Ibaraki (Japan). Nakaminato Lab. Branch Office

    1994-03-01

    Seawater and brown algae have been collected along the coast of Ibaraki Prefecture. Technetium-99 was preconcentrated from seawater by anion exchange resin, Bio-rad AG1-X8, C1-form, 50-100 mesh, and was extracted by 30% tri-n-octylamine (TOA) : xylene solution, followed by back-extraction with 5MNaOH solution. Technetium-99 was re-extracted into 2-butanone which was removed by rotary evaporator. The residue was dissolved in diluted sulfuric acid solution, in which 20mg of cupric ion was added. Technetium-99 was co-precipitated with cupric ion carrier as TcS by adding a thioacetamide solution. Algae were dried and ignited in an electric furnace at 450degC for 36h. The ash were digested with 4N nitric acid solution on a hot plate to leach technetium-99 into the nitric acid solution. The solution was centrifuged and the supernatant was processed by liquid extraction with 30% TOA-xylene solution as in the analysis of seawater. Among several species of brown algae, the highest concentration of technetium-99 was obtained in Sargassum thunbergii, which was found to be a useful indicator of technetium-99 in marine environment. (author).

  1. A primer on concentrated insulins: what an internist should know.

    Science.gov (United States)

    Barnosky, Adrienne; Shah, Lisa; Meah, Farah; Emanuele, Nicholas; Emanuele, Mary Ann; Mazhari, Alaleh

    2016-05-01

    The common insulin concentration in most preparations of insulin is 100 units per mL or U-100. Human regular U-500 insulin was the first concentrated insulin introduced and it has been available in the United States since the 1950s. Humulin R is the only human regular U-500 available on the market. Human regular U-500 is five times more concentrated than U-100 and because of its pharmacodynamic properties, works as both a basal and a bolus insulin. Human regular U500 allows for delivery of a larger insulin dose with a smaller volume leading to better absorption compared to U-100 and has traditionally been used in patients with moderate to severe insulin resistance. More recently other forms of concentrated insulin have become available and the newer concentrated insulin preparations can be used in diabetic patients with or without insulin resistance. Our intent is to provide primary care physicians with a review of the pharmacology and current literature on concentrated insulins as well as recommendations for patient selection, dose initiation, and dose adjustment. PMID:26924668

  2. Biotransformation of micropollutants: kinetics, threshold and residual concentrations.

    OpenAIRE

    Tros, M E

    1996-01-01

    The pollution of our environment with a large number of synthetic organic chemicals has raised serious concern about their toxicity to existing life forms. Microorganisms play an essential role in the breakdown of xenobiotic compounds by using them as a carbon and energy source. However, pollutants that are intrinsically biodegradable are still widespread in soil, groundwater and natural waters at typical concentrations at the nanomolar to micromolar level. This has raised questions about mic...

  3. The Determinants of Geographic Concentration of Industry: A Quantitative Analysis

    OpenAIRE

    Zhu Wang; Daniel Yi Xu; Luis Cabral

    2012-01-01

    Taking the early U.S. automobile industry as an example, we evaluate two competing hypotheses on geographic concentration of industry: local externalities versus employee spinoffs. Our findings suggest that both forces contribute to industry agglomeration through their specific channels, and the spinoff effect can be viewed as a special form of local externalities. Calibrating our model to the quantitative pattern of industry evolution reveals that traditional local externalities are main dri...

  4. Plasma phylloquinone concentrations increase following acupoint injection for primary dysmenorrhea

    OpenAIRE

    Chao, Maria T.; Wade, Christine M.; Sarah L. Booth

    2014-01-01

    Therapeutic benefits of acupoint injection of vitamin K in Spleen-6 for the treatment of primary dysmenorrhea have been observed in limited clinical settings. However, menadione, the form of vitamin K most studied for treating dysmenorrhea, is not routinely used in clinical practice in North America. As part of a larger clinical trial among women with primary dysmenorrhea aged 18 to 25 years old, we conducted a sub-study to test the plasma concentration of phylloquinone (vitamin K1). We colle...

  5. Highly concentrated emulsions. Physicochemical principles of the preparation and stability

    Energy Technology Data Exchange (ETDEWEB)

    Babak, V G [A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow (Russian Federation)

    2008-08-31

    Theoretical and experimental studies on highly concentrated emulsions are critically analysed. The views on the relationship between the stability of surfactant-stabilised emulsions and the properties of microemulsion phases formed in surfactant-water-oil ternary systems are considered. The empirical criteria and rules that can be used to predict the type and stability of emulsions are presented. The physicochemical factors determining the rupture stability of emulsion films are discussed.

  6. NITRATE AND NITRITE CONCENTRATION IN VEGETABLES GRAWING AROUND ISFAHAN CITY

    OpenAIRE

    R.A JAFARI; A AZIZ ZADEH; A FARZAN

    2001-01-01

    Introduction: The improper and excess use of chemical fertilizers by the farmers special in "urea" form may cause the commulation of nitrates and nitrites in vegetables and fruits. This investigation has been done to determine the concentration of nitrates and nitrites in some vegetables growing around Isfahan. Methods: One hundred and thirteen random samples from 15 different kinds of green lest tuber vegetables were measured by Cadmium Column Procedure for nitrates and nitrites. R...

  7. Simultaneous determination of rutin and ascorbic acid mixture in their pure forms and combined dosage form.

    Science.gov (United States)

    Attia, Tamer Z

    2016-12-01

    A simple, rapid, sensitive and selective high performance liquid chromatographic (HPLC) method with ultraviolet detection has been developed for simultaneous determination of ascorbic acid and rutin in pure forms and pharmaceutical dosage form. HPLC separation was performed on Phenomenex C18 analytical column with 0.1% v/v acetic acid in water and acetonitrile (75:25, v/v), as mobile phase. The separation was done at ambient temperature with flow rate of 1mL·min(-1) in isocratic mode. HPLC measurements were carried out using ultraviolet detection wavelength at 257nm. The average retention times were 2.72 and 7.00min for ascorbic acid and rutin, respectively. The calibration plots were constructed over the concentration range of 5.0-30.0 for ascorbic acid and 10.0-60.0μg·mL(-1) for rutin. The limits of detection were 1.06 and 1.89μg·mL(-1) and limits of quantification were 3.54 and 6.31μg·mL(-1) for ascorbic acid and rutin, respectively. The proposed HPLC-UV method was successfully applied for determination of ascorbic acid in its tablets and for simultaneous determination of the studied drugs in their laboratory prepared mixtures and in pharmaceutical formulation. Statistical comparisons of the results with the reference method show an excellent agreement and indicate no significant difference in respect to accuracy and precision. PMID:27341400

  8. Spectroscopic Studies of Carotenoid-to-Bacteriochlorophyll Energy Transfer in LHRC Photosynthetic Complex from Roseiflexus castenholzii

    Energy Technology Data Exchange (ETDEWEB)

    Niedzwiedzki, Dariusz [Washington Univ., St. Louis, MO (United States); Collins, Aaron M. [Washington Univ., St. Louis, MO (United States); LaFountain, Amy M. [Univ. of Connecticut, Storrs, CT (United States); Enriquez, Miriam M. [Univ. of Connecticut, Storrs, CT (United States); Frank, Harry A. [Washington Univ., St. Louis, MO (United States); Blankenship, R. E. [Washington Univ., St. Louis, MO (United States)

    2010-06-14

    Carotenoids present in the photosynthetic light-harvesting reaction center (LHRC) complex from chlorosome lacking filamentous anoxygenic phototroph, Roseiflexus castenholzii were purified and characterized for their photochemical properties. The LHRC from anaerobically grown cells contains five different carotenoids, methoxy-keto-myxocoxanthin, γ-carotene, and its three derivatives, whereas the LHRC from aerobically grown cells contains only three carotenoid pigments with methoxy-keto-myxocoxanthin being the dominant one. The spectroscopic properties and dynamics of excited singlet states of the carotenoids were studied by steady-state absorption, fluorescence and ultrafast time-resolved optical spectroscopy in organic solvent and in the intact LHRC complex. Time-resolved transient absorption spectroscopy performed in the near-infrared (NIR) on purified carotenoids combined with steady-state absorption spectroscopy led to the precise determination of values of the energies of the S1(21Ag-) excited state. Global and single wavelength fitting of the ultrafast spectral and temporal data sets of the carotenoids in solvents and in the LHRC revealed the pathways of de-excitation of the carotenoid excited states.

  9. Theoretical prediction of spectral and optical properties of bacteriochlorophylls in thermally disordered LH2 antenna complexes

    CERN Document Server

    Janosi, L; Kosztin, I; Damjanovic, Ana; Janosi, Lorant; Kosztin, Ioan

    2006-01-01

    A general approach for calculating spectral and optical properties of pigment-protein complexes of known atomic structure is presented. The method, that combines molecular dynamics simulations, quantum chemistry calculations and statistical mechanical modeling, is demonstrated by calculating the absorption and circular dichroism spectra of the B800-B850 BChls of the LH2 antenna complex from Rs. molischianum at room temperature. The calculated spectra are found to be in good agreement with the available experimental results. The calculations reveal that the broadening of the B800 band is mainly caused by the interactions with the polar protein environment, while the broadening of the B850 band is due to the excitonic interactions. Since it contains no fitting parameters, in principle, the proposed method can be used to predict optical spectra of arbitrary pigment-protein complexes of known structure.

  10. Alternative Waste Forms for Electro-Chemical Salt Waste

    Energy Technology Data Exchange (ETDEWEB)

    Crum, Jarrod V.; Sundaram, S. K.; Riley, Brian J.; Matyas, Josef; Arreguin, Shelly A.; Vienna, John D.

    2009-10-28

    This study was undertaken to examine alternate crystalline (ceramic/mineral) and glass waste forms for immobilizing spent salt from the Advanced Fuel Cycle Initiative (AFCI) electrochemical separations process. The AFCI is a program sponsored by U.S. Department of Energy (DOE) to develop and demonstrate a process for recycling spent nuclear fuel (SNF). The electrochemical process is a molten salt process for the reprocessing of spent nuclear fuel in an electrorefiner and generates spent salt that is contaminated with alkali, alkaline earths, and lanthanide fission products (FP) that must either be cleaned of fission products or eventually replaced with new salt to maintain separations efficiency. Currently, these spent salts are mixed with zeolite to form sodalite in a glass-bonded waste form. The focus of this study was to investigate alternate waste forms to immobilize spent salt. On a mole basis, the spent salt is dominated by alkali and Cl with minor amounts of alkaline earth and lanthanides. In the study reported here, we made an effort to explore glass systems that are more compatible with Cl and have not been previously considered for use as waste forms. In addition, alternate methods were explored with the hope of finding a way to produce a sodalite that is more accepting of as many FP present in the spent salt as possible. This study was done to investigate two different options: (1) alternate glass families that incorporate increased concentrations of Cl; and (2) alternate methods to produce a mineral waste form.

  11. Decomposition of high concentration SF6 using an electron beam

    Science.gov (United States)

    Son, Youn-Suk; Lee, Sung-Joo; Choi, Chang Yong; Park, Jun-Hyeong; Kim, Tak-Hyun; Jung, In-Ha

    2016-07-01

    In this study, high concentration SF6 (2-10%) was decomposed using an electron beam irradiation. Various influential factors were investigated to improve the destruction and removal efficiency (DRE) of SF6. The initial concentrations of SF6, absorbed doses, SF6/H2 ratios and retention times were the main factors of concern. As a result, the DRE increased as the adsorbed dose and retention time increased. The DRE of SF6 also increased up to 20% approximately when H2 was added to the reaction mixture. On the other hand, the DRE of SF6 decreased as initial concentrations of SF6 increased. Finally, the main by-product formed from SF6 decomposition by the electron beam was HF.

  12. Separation and concentration of uranium by ion flotation method

    International Nuclear Information System (INIS)

    The concentration of uranium from seawater has been investigated from the viewpoint of adsorption method and coprecipitation method. In this study a procedure is described for the separation of uranium present as a stable uranyl cation or a tricarbonatouranyl anion by ion flotation which utilizes dicarboxylate and quaternary ammonium chloride as a collector, respectively. When dicarboxylate was used, uranium floated in the pH region, 3--7 and the maximum recovery was 93% at pH 5. When quaternary ammonium chloride was used, uranium floated at pH values above about 4 and the maximum recovery was 95% at pH 8. The former has the high concentration ratio because the floated uranium forms a scum, while the latter has the lower concentration ratio because uranium floats with foam. (auth.)

  13. Influence of process parameters on hybrid forming of aluminum sheet

    Institute of Scientific and Technical Information of China (English)

    张新明; 陈明安

    2001-01-01

    The influences of the plastic melt pressure and its distribution from the gate to the end of the mold, and of the friction coefficient between the sheet flange and the mold on forming process of the aluminum sheet have been investigated by Finite Element Method. It was shown that further deformation is mainly concentrated on metal sheet around the root corner of the mold, and that two highly strained zones with the severest thickness reduction are formed when the plastic melt pressure increased from 30 MPa to 50 MPa. The deformation of the sheet flange decreased and biaxial tension in plane of the sheet in the mold increased with increase of the friction coefficient. The non-uniform distribution of the plastic melt pressure had negligible influence on forming process of the sheet.

  14. Estimating Lexical Priors for Low-Frequency Syncretic Forms

    CERN Document Server

    Baayen, H; Baayen, Harald; Sproat, Richard

    1995-01-01

    Given a previously unseen form that is morphologically n-ways ambiguous, what is the best estimator for the lexical prior probabilities for the various functions of the form? We argue that the best estimator is provided by computing the relative frequencies of the various functions among the hapax legomena --- the forms that occur exactly once in a corpus. This result has important implications for the development of stochastic morphological taggers, especially when some initial hand-tagging of a corpus is required: For predicting lexical priors for very low-frequency morphologically ambiguous types (most of which would not occur in any given corpus) one should concentrate on tagging a good representative sample of the hapax legomena, rather than extensively tagging words of all frequency ranges.

  15. Travel and urban form in the Greater Copenhagen region

    DEFF Research Database (Denmark)

    Nielsen, Thomas Alexander Sick

    of the economic upturn – with a later point in time where the financial crisis had radically changed the economic climate. It follows from the specificity of the historical events that an analysis of what happened to urban form and transport over the financial crisis is to be seen as a case study......Research into the associations between urban form and travel in the capital areal has focussed on subcenters and the stability of urban form correlates over time. A trend towards de-concentration and formation of subcenters in metropolitan areas has been acknowledged for decades. Studies have...... aimed to identify subcenters in the Greater Copenhagen area and analyze their importance for property values as well as on travel demand. Subcenters are identified by applying spatial statistics to on available spatially explicit datasets representing jobs in general and retail jobs. Home price...

  16. New CERN Health Insurance Scheme (CHIS) forms

    CERN Multimedia

    HR Department

    2015-01-01

    New versions of the following forms for claims and requests to the CERN Health Insurance Scheme (CHIS) have been released:   form for claiming reimbursement of medical expenses,   form for requesting advance reimbursement, and   dental estimate form (for treatments foreseen to exceed 800 CHF).   The new forms are available in French and English. They can either be completed electronically before being printed and signed, or completed in paper form. New detailed instructions can be found at the back of the claim form; CHIS members are invited to read them carefully. The electronic versions (PDF) of all the forms are available on the CHIS website and on the UNIQA Member Portal. CHIS Members are requested to use these new forms forthwith and to discard any previous version. Questions regarding the above should be addressed directly to UNIQA (72730 or 022.718 63 00 or uniqa.assurances@cern.ch).

  17. Crystallization and Characterization of Galdieria sulphuraria RUBISCO in Two Crystal Forms: Structural Phase Transition Observed in P21 Crystal Form

    Directory of Open Access Journals (Sweden)

    Boguslaw Stec

    2007-10-01

    Full Text Available We have isolated ribulose-1,5-bisphosphate-carboxylase/oxygenase (RUBISCOfrom the red algae Galdieria Sulphuraria. The protein crystallized in two different crystalforms, the I422 crystal form being obtained from high salt and the P21 crystal form beingobtained from lower concentration of salt and PEG. We report here the crystallization,preliminary stages of structure determination and the detection of the structural phasetransition in the P21 crystal form of G. sulphuraria RUBISCO. This red algae enzymebelongs to the hexadecameric class (L8S8 with an approximate molecular weight 0.6MDa.The phase transition in G. sulphuraria RUBISCO leads from two hexadecamers to a singlehexadecamer per asymmetric unit. The preservation of diffraction power in a phasetransition for such a large macromolecule is rare.

  18. 2011 NATA - Risks and Annual Ambient Concentrations

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset includes the modeled annual ambient concentrations and risks at the census tract level for the 2011 National Air Toxics Assessment. All concentrations...

  19. Medical Oxygen Concentrator for Microgravity Operation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We have all seen people carrying portable oxygen tanks or concentrators to provide critical life support respiratory oxygen. Heavy, bulky, and for O2 concentrators,...

  20. Inorganic sorbents for concentration of hydrogen sulfide

    International Nuclear Information System (INIS)

    Present work is devoted to application of inorganic sorbents for concentration of hydrogen sulfide. The elaboration of method is conducted under controlled concentrations of hydrogen sulphide from 1.00 til 0.01 mg/l.