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Sample records for lvealyl forms microcrystalline

  1. Crystallization of II-VI semiconductor compounds forming long microcrystalline linear assemblies

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    Marcelino Becerril

    2013-04-01

    Full Text Available In this work we report the formation of long microcrystalline linear self-assemblies observed during the thin film growth of several II-VI compounds. Polycrystalline CdTe, CdS, CdCO3, and nanocrystalline CdTe:Al thin films were prepared on glass substrates by different deposition techniques. In order to observe these crystalline formations in the polycrystalline materials, the thin film growth was suspended before the grains reached to form a continuous layer. The chains of semiconductor crystals were observed among many isolated and randomly distributed grains. Since CdTe, CdTe:Al, CdS and CdCO3 are not ferroelectric and/or ferromagnetic materials, the relevant problem would be to explain what is the mechanism through which the grains are held together to form linear chains. It is well known that some nanocrystalline materials form rods and wires by means of electrostatic forces. This occurs in polar semiconductors, where it is assumed that the attraction forces between surface polar faces of the small crystals are the responsible for the chains formation. Since there are not too many mechanisms responsible for the attraction we assume that a dipolar interaction is the force that originates the formation of chain-like grain clusters. The study of this property can be useful for the understanding of nucleation processes in the growth of semiconductor thin films.

  2. Molecular basis for insulin fibril assembly

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    Ivanova, Magdalena I.; Sievers, Stuart A.; Sawaya, Michael R.; Wall, Joseph S.; Eisenberg, David; (HHMI); (BNL)

    2009-12-01

    In the rare medical condition termed injection amyloidosis, extracellular fibrils of insulin are observed. We found that the segment of the insulin B-chain with sequence LVEALYL is the smallest segment that both nucleates and inhibits the fibrillation of full-length insulin in a molar ratio-dependent manner, suggesting that this segment is central to the cross-{beta} spine of the insulin fibril. In isolation from the rest of the protein, LVEALYL forms microcrystalline aggregates with fibrillar morphology, the structure of which we determined to 1 {angstrom} resolution. The LVEALYL segments are stacked into pairs of tightly interdigitated {beta}-sheets, each pair displaying the dry steric zipper interface typical of amyloid-like fibrils. This structure leads to a model for fibrils of human insulin consistent with electron microscopic, x-ray fiber diffraction, and biochemical studies.

  3. Effects of initial layers on surface roughness and crystallinity of microcrystalline silicon thin films formed by remote electron cyclotron resonance silane plasma

    CERN Document Server

    Murata, K; Hori, Masaki; Goto, T; Ito, M

    2002-01-01

    We have observed mu c-Si:H films grown in the glass substrate in electron cyclotron resonance plasma-enhanced chemical vapor deposition employing two-step growth (TSG) method, where the seed layer was formed without charged species firstly, and subsequently, the film with charged species. The mu c-Si:H films with smooth surface and high crystallinity were synthesized with a relatively high deposition rate at a low substrate temperature by TSG. By Fourier transform infrared attenuated-total reflection, it was found that the surface roughness and crystallinity of seed layer were related to the ratio of SiH bonds over SiH sub 2 ones in the film. Consequently, the control of chemical bonds at the initial layer is of importance and TSG method is effective for the formation of mu c-Si:H film with high quality.

  4. Pain and microcrystalline arthritis

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    R. Ramonda

    2014-06-01

    Full Text Available Microcrystals are responsible for some of the most common and complex arthropathies which are often accompanied by intense, severe pain and inflammatory reactions. The main pathogens are crystals of monosodium urate (MSU, responsible for the gout, calcium pyrophosphate (CPP, which deposits also in various clinical forms of arthopathies, and basic calcium phosphate associated with osteoarthritis. In this context, the microcrystal arthritis is characterized by multiple, acute attacks followed by chronic pain, disability, impaired quality of life, and increased mortality. Given their chronic nature, they represent an ever more urgent public health problem. MSU and CPP crystals are also able to activate nociceptors. The pain in mycrocrystalline arthritis (MCA is an expression of the inflammatory process. In the course of these diseases there is an abundant release of inflammatory molecules, including prostaglandins 2 and kinins. Interleukin-1 represents the most important cytokine released during the crystal-induced inflammatory process. Therefore, clinically, pain is the most important component of MCA, which lead to functional impairment and disability in a large proportion of the population. It is fundamental to diagnose these diseases as early as possible, and to this aim, to identify appropriate and specific targets for a timely therapeutic intervention.

  5. Structural changes in microcrystalline cellulose in subcritical water treatment.

    Science.gov (United States)

    Tolonen, Lasse K; Zuckerstätter, Gerhard; Penttilä, Paavo A; Milacher, Walter; Habicht, Wilhelm; Serimaa, Ritva; Kruse, Andrea; Sixta, Herbert

    2011-07-11

    Subcritical water is a high potential green chemical for the hydrolysis of cellulose. In this study microcrystalline cellulose was treated in subcritical water to study structural changes of the cellulose residues. The alterations in particle size and appearance were studied by scanning electron microscopy (SEM) and those in the degree of polymerization (DP) and molar mass distributions by gel permeation chromatography (GPC). Further, changes in crystallinity and crystallite dimensions were quantified by wide-angle X-ray scattering and (13)C solid-state NMR. The results showed that the crystallinity remained practically unchanged throughout the treatment, whereas the size of the remaining cellulose crystallites increased. Microcrystalline cellulose underwent significant depolymerization in subcritical water. However, depolymerization leveled off at a relatively high degree of polymerization. The molar mass distributions of the residues showed a bimodal form. We infer that cellulose gets dissolved in subcritical water only after extensive depolymerization.

  6. Tips and tricks to recognize microcrystalline arthritis

    National Research Council Canada - National Science Library

    Filippucci, Emilio; Di Geso, Luca; Grassi, Walter

    2012-01-01

    .... The knowledge of some tips and tricks in the identification of these findings can play a key role in exploiting the relevant potential of US in microcrystalline arthritis, avoiding errors and misinterpretations...

  7. Tips and tricks to recognize microcrystalline arthritis.

    Science.gov (United States)

    Filippucci, Emilio; Di Geso, Luca; Grassi, Walter

    2012-12-01

    US plays a useful role in diagnosing and monitoring therapy in microcrystalline arthritis, as it may detect both monosodium urate and calcium pyrophosphate crystal aggregates. The knowledge of some tips and tricks in the identification of these findings can play a key role in exploiting the relevant potential of US in microcrystalline arthritis, avoiding errors and misinterpretations. This review provides an in-depth description of simple technical and methodological issues to guide the rheumatologist in daily clinical practice.

  8. Compactibility of agglomerated mixtures of calcium carbonate and microcrystalline cellulose.

    Science.gov (United States)

    Garzón Serra, María de Lourdes; Villafuerte Robles, Leopoldo

    2003-06-04

    The tablet tensile strength (T) of agglomerated mixtures of microcrystalline cellulose-Avicel PH 102 (MC), calcium carbonate (CC) and polyvinylpyrrolidone (Povidone, PVP), lubricated with magnesium stearate (MS), and formed under a compaction pressure (P(c)) ranging up to 618MPa has been determined. The compactibility was defined through: ln(-ln(1-T/T(max)))=Slope x lnP(c)+Intercept. MC/CC mixtures added of an agglutinant, before and after lubrication, show an important positive effect on their tablet tensile strength compared to a lineal relationship. This positive effect becomes smaller with decreasing compaction pressures. By different mixing methods, the higher the mixing efficiency the higher the compactibility, following the order: spray-dried>wet massing>tumble mixing. The compactibility of MC/CC/PVP spray-dried mixtures with calcium carbonate content from 20 to 60% was equal to or greater than that of pure microcrystalline cellulose. After lubrication with 2% MS the compactibility decreased, only the mixture with the maximal tablet tensile strength attained the tensile strength of pure microcrystalline cellulose. The presence of the binder, the lubricant and higher compaction pressures allow the accommodation of higher calcium carbonate proportions in the mixtures, at the maximal tablet tensile strength of the series. The lubricant decreases in a greater extent the compactibility of mixtures with a continuous phase of MC/PVP than that of CC/PVP. This is attributed to the plastic behavior of the MC/PVP continuous phase compared to a calcium carbonate continuous phase able to disrupt the Povidone and the possible lubricant coatings allowing a stronger interparticle interaction.

  9. Some historical remarks on microcrystalline arthritis (gout and chondrocalcinosis

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    G. Pasero

    2012-01-01

    Full Text Available The history of microcrystalline arthritis only began in 1961 when Daniel McCarty and Joseph Lee Hollander demonstrated the presence of sodium monourate crystals in the synovial fluid of gouty patients. However, gout is a historical disease, thanks to the descriptions of Hippocrates, Caelius Aurelianus, Soranus of Ephesus and Araeteus of Cappadocia. The relationship between hyperuricemia and gout was first documented in the nineteenth century by Alfred Baring Garrod, who demonstrated deposits of uric acid crystals on a linen thread held dipped in acidified blood (the so-called “thread method”. Gout has always been considered a prerogative of the moneyed classes (arthritis divitum, and history is full of famous gouty personalities, including kings, emperors, popes, commanders, politicians, artists, writers, philosophers and scientists. Another form of microcrystalline arthritis, chondrocalcinosis, was identified as being a rheumatic disorder different from gout in the 1960s. As a specific clinical entity, it was first identified in 1958 by Dušan Žitnˇan and Štefan Sit’aj in a few Slovak families.

  10. Novel co-processed excipients of mannitol and microcrystalline cellulose for preparing fast dissolving tablets of glipizide

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    Jacob S

    2007-01-01

    Full Text Available Co-processed particles of microcrystalline cellulose and mannitol were fabricated by spray drying technique to be used as a direct compression excipient in fast dissolving tablet formulation. Microcrystalline cellulose passed through sieve no.80, having a volumetric mean diameter (d 50 of 28.35 µm, was used to form composite particles with powdered mannitol which was previously passed through sieve no. 80, in various mixing ratios. The composite particles were evaluated for their powder and compression properties. An increase in the microcrystalline cellulose proportion imparted greater compressibility to the composite particles, but the flowability of these mixtures was decreased. Although microcrystalline cellulose and mannitol have been extensively used in the formulation of fast dissolving tablets, the non-wetting property of the hard compact central core may delay the disintegration time. Optimized co-processed formulation containing mannitol and microcrystalline cellulose in the ratio of 1.25:1 was found to have optimized powder and compressibility characteristics with fast disintegrating property (< 15 s. Photomicrographs have shown that the mannitol crystals are fine and uniformly distributed in the microcrystalline matrix in spray dried form compared to physical mixture of the same combination. The fast disintegration may be due to the partial amorphization and formation of submicron particles of mannitol. These results indicated that improved fast dissolving tablets could be prepared by the co-processed mixture of microcrystalline cellulose and mannitol. Finally fast dissolving tablets of glipizide were prepared by blending with other excipients and compressed into tablets. Sensory study on disintegration time and mouth feel attributes ranked the present formulation based on grittiness, chalkiness and overall preference as the best.

  11. Preparation of microcrystalline single junction and amorphous-microcrystalline tandem silicon solar cells entirely by hot-wire CVD

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    Kupich, M.; Grunsky, D.; Kumar, P.; Schroeder, B. [University of Kaiserslautern (Germany). Department of Physics

    2004-01-25

    The hot-wire chemical vapour deposition (HWCVD) has been used to prepare highly conducting p- and n-doped microcrystalline silicon thin layers as well as highly photoconducting, low defect density intrinsic microcrystalline silicon films. These films were incorporated in all-HWCVD, all-microcrystalline nip and pin solar cells, achieving conversion efficiencies of {eta}=5.4% and 4.5%, respectively. At present, only the nip-structures are found to be stable against light-induced degradation. Furthermore, microcrystalline nip and pin structures have been successfully incorporated as bottom cells in all-hot-wire amorphous-microcrystalline nipnip- and pinpin-tandem solar cells for the first time. So far, the highest conversion efficiencies of the 'micromorph' tandem structures are {eta}=5.7% for pinpin-solar cells and 7.0% for nipnip solar cells. (author)

  12. Method for depositing high-quality microcrystalline semiconductor materials

    Science.gov (United States)

    Guha, Subhendu; Yang, Chi C.; Yan, Baojie

    2011-03-08

    A process for the plasma deposition of a layer of a microcrystalline semiconductor material is carried out by energizing a process gas which includes a precursor of the semiconductor material and a diluent with electromagnetic energy so as to create a plasma therefrom. The plasma deposits a layer of the microcrystalline semiconductor material onto the substrate. The concentration of the diluent in the process gas is varied as a function of the thickness of the layer of microcrystalline semiconductor material which has been deposited. Also disclosed is the use of the process for the preparation of an N-I-P type photovoltaic device.

  13. Observation of a microcrystalline gel in colloids with competing interactions.

    Science.gov (United States)

    Zhang, Tian Hui; Groenewold, Jan; Kegel, Willem K

    2009-12-14

    A stable short-range crystalline structure is observed in colloidal systems with competing short-range attractions and long-range repulsions. We term these structures "microcrystalline gels" as the microcrystals are embedded in a dense disordered network.

  14. Compaction mechanism and tablet strength of unlubricated and lubricated (silicified) microcrystalline cellulose

    NARCIS (Netherlands)

    van Veen, B; Bolhuis, G K; Wu, Y S; Zuurman, K; Frijlink, H W

    This paper describes the differences in compaction properties between microcrystalline cellulose (MCC) and microcrystalline cellulose co-processed with colloidal silicon dioxide (SMCC). The different compaction parameters are not only compared for the pure materials, but also for the lubricated

  15. Investigation into the suitability of capillary tubes for microcrystalline testing.

    Science.gov (United States)

    Elie, Leonie E; Baron, Mark G; Croxton, Ruth S; Elie, Mathieu P

    2013-07-01

    A comparison between microcrystalline tests performed on microscope slides and flat capillary tubes with inner diameters ranging from 0.1 to 0.7 mm was carried out to explore the appropriateness of tubes for rapid testing of suspected drugs of abuse in the laboratory as well as in the field. Tests for mephedrone, cocaine, and phencyclidine were chosen as examples to investigate the handling of the capillary tubes, the influence on crystal habit, size, and the effects on the limit of detection. Image stacking software was used to increase the depth of field of micrographs taken from developed microcrystals greatly enhancing the interpretability even months after carrying out the microcrystalline test. Additionally, the potential of seeding capillary tubes with a reagent was studied. Pre-treatment of tubes would allow microcrystalline tests to be carried out quicker and anywhere without the necessity of taking along expensive and hazardous reagents. The sealing of capillary tubes containing developed microcrystalline tests in order to preserve results for a long period of time was successfully done by applying paraffin wax to the open ends. Finally, it was concluded that capillary tubes are suitable vessels for performing microcrystalline tests. The increased portability of the improved set-up allows tests to be safely executed outside laboratories without impairing the quality of the result. Findings were applied to six legal high samples purchased online between May and August 2011. The active ingredients like MDAI as well as cutting agents like caffeine were successfully identified using the microcrystalline test technique in capillary tubes.

  16. Microcrystalline hexagonal tungsten bronze. 2. Dehydration dynamics.

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    Luca, Vittorio; Griffith, Christopher S; Hanna, John V

    2009-07-06

    Low-temperature (25-600 degrees C) thermal transformations have been studied for hydrothermally prepared, microcrystalline hexagonal tungsten bronze (HTB) phases A(x)WO(3+x/2).zH(2)O as a function of temperature, where A is an exchangeable cation (in this case Na(+) or Cs(+)) located in hexagonal structural tunnels. Thermal treatment of the as-prepared sodium- and cesium-exchanged phases in air were monitored using a conventional laboratory-based X-ray diffractometer, while thermal transformations in vacuum were studied using synchrotron X-ray and neutron diffraction. Concurrent thermogravimetric, diffuse reflectance infrared (DRIFT), and (23)Na and (133)Cs magic angle spinning (MAS) NMR spectroscopic studies have also been undertaken. For the cesium variant, cell volume contraction occurred from room temperature to about 350 degrees C, the regime in which water was "squeezed" out of tunnel sites. This was followed by a lattice expansion in the 350-600 degrees C temperature range. Over the entire temperature range, a net thermal contraction was observed, and this was the result of an anisotropic change in the cell dimensions which included a shortening of the A-O2 bond length. These changes explain why Cs(+) ions are locked into tunnel positions at temperatures as low as 400 degrees C, subsequently inducing a significant reduction in Cs(+) extractability under low pH (nitric acid) conditions. The changing Cs(+) speciation as detected by (133)Cs MAS NMR showed a condensation from multiple Cs sites, presumably associated with differing modes of Cs(+) hydration in the tunnels, to a single Cs(+) environment upon thermal transformation and water removal. While similar lattice contraction was observed for the as-prepared sodium variant, the smaller radius of Na(+) caused it to be relatively easily removed with acid in comparison to the Cs(+) variant. From (23)Na MAS NMR studies of the parent material, complex Na(+) speciation was observed with dehydrated and various

  17. Compactibility of mixtures of calcium carbonate and microcrystalline cellulose.

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    Garzón, M de Lourdes; Villafuerte, Leopoldo

    2002-01-01

    A patented coprocessed mixture of microcrystalline cellulose (MC) and calcium carbonate (CC) is claimed to perform, as a pharmaceutical excipient, equal or better than pure MC. To investigate it, the tensile strength (T) of tablets made of mixtures of MC type 102, CC, magnesium stearate (MS) and polyvinylpyrrolidone (PVP) and formed under a compaction pressure (P(c)) ranging up to 618 MPa has been determined. The compactibility of the mixtures was defined through regression parameters obtained with ln(-ln(1-T/T(max)))=slope x lnP(c) + intercept. MC/CC mixtures, P(c)=618 MPa, show a small decrease in tablet tensile strength with CC proportions up to about 20%, falling considerably thereafter. Lower compaction pressures, P(c)tablet tensile strength due to 2%-MS, P(c)=487 MPa, was recovered to 35% of its original value admixing about 25% CC. This maximal value of recovery showed a shift to lower proportions of CC, up to 10%, as compaction pressure decreased. This was attributed to lower CC-particles fragmentation or agglomerates spreading at lower compaction pressures. Mixtures with increased plasticity (MC/CC/PVP and MC/CC/PVP/MS) showed an increased compactibility, which was more evident at higher compaction pressures and higher CC proportions, presumably due to higher deformation and erosion of PVP particles. Inclusion of about 40% CC in a MC/PVP/MS mixture showed 60% recovery of the original MC tablet tensile strength. Lower MS proportions are expected to allow a higher recovery.

  18. Observation of a microcrystalline gel in colloids with competing interactions

    NARCIS (Netherlands)

    Zhang, T.; Groenewold, J.; Kegel, W.K.

    2009-01-01

    A stable short-range crystalline structure is observed in colloidal systems with competing short-range attractions and long-range repulsions. We term these structures ‘‘microcrystalline gels’’ as the microcrystals are embedded in a dense disordered network.

  19. Solution growth of microcrystalline silicon on amorphous substrates

    Energy Technology Data Exchange (ETDEWEB)

    Heimburger, Robert

    2010-07-05

    material is proposed. MoSi{sub 2} thin films on glass, produced by annealing near-stoichiometric Mo-Si multilayers, are shown to resist solution contact. Subsequent investigation of feasibility of the vapor-liquid-solid mechanism revealed the success of indium microdroplet formation to be determined by both, the multilayer deposition parameters and the substrate temperature during indium deposition. Steady-state solution growth at 610 C was utilized to enlarge silicon seed crystals to diameters of up to 200 {mu}m. The grown material has been subject of characterization regarding the crystallinity, orientation and purity. Additionally, morphological anomalies are considered. The outgrown material was found to be bound by {l_brace}111{r_brace} facets. Many of these microcrystallites contain at least two twin domains. Twin-assisted growth at formed re-entrant edges promotes high growth rates even at low supersaturation. Additionally, many crystallites exhibit hoppers at the center of their facets. This is explained by a solute concentration inhomogeneity within the diffusion boundary layer of the nutrient solution leading to solute depletion at the facet centers and to morphological instability. The feasibility of the process for growth of microcrystalline silicon on glass has been shown in principle. Nevertheless, limitations exist regarding the achievable crystalline solidity ratio and the size of crystallites grown under stable conditions. (orig.)

  20. Stability of thin films of microcrystalline silicon under light soaking

    Institute of Scientific and Technical Information of China (English)

    HAN Xiao-yan; Wang Yan; XUE Jun-ming; ZHAO Shu-wen; REN Hui-zhi; ZHAO Ying; LI Yang-xian; GENG Xin-hua

    2006-01-01

    Silicon thin films with different crystalline ratio(Xc) have been deposited by varying silane content(SC) of reactive gases in the RF-PECVD process.The effects of silane content on performance of the materials and the relationship between microstructure and opto-electronic properties were studied by means of Raman measurements,photoconductivity(σph),and dark conductivity(σd),followed by the measurements of light absorption coefficient(α),the product of quantum efficiency,mobility and lifetime (ημτ),before,during and after light soaking,respectively.The results indicate that the microcrystalline silicon near the transition region is suitable to prepare microcrystalline silicon of device grade,and that the amorphous region of the material is responsible to the light induced degradation.

  1. Carrier mobility, band tails and defects in microcrystalline silicon

    Science.gov (United States)

    Reynolds, Steve

    2010-11-01

    The development of microcrystalline silicon thin films and devices is briefly reviewed. Transport mechanisms, and the attendant key parameters of carrier mobility, band-tail width and defect density, are linked to film structure and composition. In particular we discuss the wide (but systematic) variations in time-of-flight mobility and its unusual field-dependence. While microcrystalline silicon remains an inferior semiconductor to single-crystal silicon, we propose, and support by means of a computer model, that present device-grade material may be of sufficient quality to justify re-examining whether useful thin-film bipolar devices might be developed. These could find application as more sensitive photo-detectors, and as current drivers in organic LED displays and logic circuits.

  2. Development and characterization of hybrid materials based on biodegradable PLA matrix, microcrystalline cellulose and organophilic silica

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    Fernanda Abbate dos Santos

    2014-10-01

    Full Text Available The goal of this work was to investigate the production and properties of hybrid materials based on poly(lactic acid (PLA, employing microcrystalline cellulose (MCC and organophilic silica (R972 as fillers. The composites were obtained by solution casting to form films. Each nanoparticle was incorporated at 3 wt. %, relative to the polymer matrix. In this experiment, four films were obtained (PLA, PLA/MCC, PLA/R972 and PLA/MCC/R972. The films properties were evaluated by X-ray diffractometry, nuclear magnetic resonance, Fourier transform infrared spectroscopy and mechanical properties. The results showed that each nanoparticle, added individually or both combined, had different effect on the final properties of the films. Microcrystalline cellulose can act as nucleating agent for the crystallization of PLA. Silica promoted an increase in rigidity, due to the strong intermolecular forces, while MCC addition promoted an increase in the molecular mobility of the polymeric chains. The PLA/MCC/R972 film showed the highest crystallinity degree and tensile modulus. This film presented a T1H value between both values found for PLA/MCC and PLA/R972 films. The results indicated that silica R972 could promote a decrease of the surface tension between PLA and cellulose.

  3. Identification of microcrystalline rocks using thermal emission spectroscopy

    Science.gov (United States)

    Hardgrove, C. J.; Rogers, D.; Glotch, T. D.; Arnold, J. A.

    2015-12-01

    High-silica deposits on Mars have been discovered from orbit (Holden Crater, Mawrth Vallis) and from landed surface missions to both Gusev Crater (Spirit) and Gale Crater (Curiosity). The character of these silica deposits can be used to understand both the depositional environment (i.e. fumarole vs. sinter) and/or diagenetic process. Initial work has shown that, in the case of opaline silica, there are differences in spectral shape that may be related to surface textural features imparted during formation or post-depositional alteration. Due to the increasing importance of understanding microcrystalline deposits on Mars, here, we study the effects of crystal size and surface roughness on thermal infrared emission spectra of micro- and macro-crystalline quartz. The spectra of chert and macro-crystalline quartz have significant differences in both spectral contrast, and in the rounded doublet between ~1000-1250 cm-1, which can shift and appear less rounded in microcrystalline samples. We find that microcrystalline minerals exhibit naturally rough surfaces compared to their macrocrystalline counterparts at the 10 micron scale; and that this roughness causes distinct spectral differences within the Reststrahlen bands. We find that surface roughness, if rough on the scale of the wavelengths where the wavelength-dependent absorption coefficient (k) is large, can cause not only decreased spectral contrast, but also substantial changes in spectral shape. The spectral shape differences are small enough that the composition of the material is still recognizable, but large enough such that a roughness effect could be detected. We find that my studying the thermal infrared spectral character of the sample, it may be possible to make general inferences about microcrystallinity, and thus aid in the potential reconstruction of sedimentary rock diagenesis.

  4. Non-wood Fibre Production of Microcrystalline Cellulose from Sorghum caudatum: Characterisation and Tableting Properties

    OpenAIRE

    Ohwoavworhua, F. O.; Adelakun, T. A.

    2010-01-01

    The microcrystalline cellulose is an important ingredient in pharmaceutical, food, cosmetic and other industries. In this study, the microcrystalline cellulose, obtained from the stalk of Sorghum caudatum was evaluated for its physical and tableting characteristics with a view to assessing its usefulness in pharmaceutical tableting. The microcrystalline cellulose, obtained from the stalk of Sorghum caudatum, obtained by sodium hydroxide delignification followed by sodium hypochlorite bleachin...

  5. Isolation and characterization of microcrystalline cellulose from oil palm biomass residue.

    Science.gov (United States)

    Mohamad Haafiz, M K; Eichhorn, S J; Hassan, Azman; Jawaid, M

    2013-04-02

    In this work, we successfully isolated microcrystalline cellulose (MCC) from oil palm empty fruit bunch (OPEFB) fiber-total chlorine free (TCF) pulp using acid hydrolysis method. TCF pulp bleaching carried out using an oxygen-ozone-hydrogen peroxide bleaching sequence. Fourier transform infrared (FT-IR) spectroscopy indicates that acid hydrolysis does not affect the chemical structure of the cellulosic fragments. The morphology of the hydrolyzed MCC was investigated using scanning electron microscopy (SEM), showing a compact structure and a rough surface. Furthermore, atomic force microscopy (AFM) image of the surface indicates the presence of spherical features. X-ray diffraction (XRD) shows that the MCC produced is a cellulose-I polymorph, with 87% crystallinity. The MCC obtained from OPEFB-pulp is shown to have a good thermal stability. The potential for a range of applications such as green nano biocomposites reinforced with this form of MCC and pharmaceutical tableting material is discussed.

  6. Comparison of microcrystalline characterization results from oil palm midrib alpha cellulose using different delignization method

    Science.gov (United States)

    Yuliasmi, S.; Pardede, T. R.; Nerdy; Syahputra, H.

    2017-03-01

    Oil palm midrib is one of the waste generated by palm plants containing 34.89% cellulose. Cellulose has the potential to produce microcrystalline cellulose can be used as an excipient in tablet formulations by direct compression. Microcrystalline cellulose is the result of a controlled hydrolysis of alpha cellulose, so the alpha cellulose extraction process of oil palm midrib greatly affect the quality of the resulting microcrystalline cellulose. The purpose of this study was to compare the microcrystalline cellulose produced from alpha cellulose extracted from oil palm midrib by two different methods. Fisrt delignization method uses sodium hydroxide. Second method uses a mixture of nitric acid and sodium nitrite, and continued with sodium hydroxide and sodium sulfite. Microcrystalline cellulose obtained by both method was characterized separately, including organoleptic test, color reagents test, dissolution test, pH test and determination of functional groups by FTIR. The results was compared with microcrystalline cellulose which has been available on the market. The characterization results showed that microcrystalline cellulose obtained by first method has the most similar characteristics to the microcrystalline cellulose available in the market.

  7. Numerical simulations for the effiency improvement of hybrid dye-microcrystalline silicon pin-solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Burdorf, Sven; Bauer, Gottfried Heinrich; Brueggemann, Rudolf [Institut fuer Physik, Carl von Ossietzky Universitaet, Oldenburg (Germany)

    2011-07-01

    Hybrid solar cells consisting of dye sensitizers incorporated in the i-layer of microcrystalline silicon pin solar cell have been proposed and even recently processed. The dye sensitizer molecules are embedded in the matrix and enhance the overall absorption of the dye-matrix system due to their high absorption coefficient in the spectral range interesting for photovoltaic applications. However, the charge transport properties of dyes are quite poor. Microcrystalline silicon on the other hand has acceptable charge transport properties, while the absorption, given a layer thickness in the micron range, is relatively poor. This contribution investigates the effiency improvement of hybrid dye-microcrystalline solar cells compared to pure microcrystalline solar cells by simulation. The results indicate that, under optimal conditions, the effiency can be improved by more than 20 % compared to a pure microcrystalline silicon cell. The thickness reduction for the hybrid system can be as large as 50 % for the same effiency.

  8. Characterization of Epoxy Composites Reinforced with Wax Encapsulated Microcrystalline Cellulose

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    Yuanfeng Pan

    2016-11-01

    Full Text Available The effect of paraffin wax encapsulated microcrystalline cellulose (EMC particles on the mechanical and physical properties of EMC/epoxy composites were investigated. It was demonstrated that the compatibility between cellulose and epoxy resin could be maintained due to partial encapsulation resulting in an improvement in epoxy composite mechanical properties. This work was unique because it was possible to improve the physical and mechanical properties of the EMC/epoxy composites while encapsulating the microcrystalline cellulose (MCC for a more homogeneous dispersion. The addition of EMC could increase the stiffness of epoxy composites, especially when the composites were wet. The 1% EMC loading with a 1:2 ratio of wax:MCC demonstrated the best reinforcement for both dry and wet properties. The decomposition temperature of epoxy was preserved up to a 5% EMC loading and for different wax:MCC ratios. An increase in wax encapsulated cellulose loading did increase water absorption but overall this absorption was still low (<1% for all composites.

  9. Scientific Opinion on the re-evaluation of microcrystalline wax (E 905 as a food additive

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    EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS

    2013-04-01

    Full Text Available Following a request from the European Commission, the Panel on Food Additives and Nutrient Sources added to Food (ANS was asked to deliver a scientific opinion on microcrystalline wax (E 905 when used as a food additive. Microcrystalline wax (E 905 is authorised quantum satis as a surface treatment agent on non-chocolate confectionery, chewing gum and decorations, coatings and fillings, except fruit based fillings. It is also permitted as a surface treatment of melons, papaya, mango and avocado. The substance was evaluated by the Scientific Committee on Food (SCF in 1990 and 1995 and by the Joint FAO/WHO Expert Committee on Food Additives (JECFA, the latest in 1995. The JECFA established a group ADI of 20 mg/kg bw/day for mineral oils, paraffins and microcrystalline waxes. The Panel noted that all mineral oil products accumulated in tissues in a dose- and time-dependent manner with the exception of microcrystalline waxes. The Panel concluded that there is no concern for genotoxicity from microcrystalline wax (E 905. The Panel also considered that the available toxicity studies with mineral hydrocarbons, closely related from a chemical point of view with microcrystalline waxes, consistently reported no effects of concern associated with the intake of microcrystalline wax. The Panel further concluded that since no long-term toxicity and carcinogenicity studies with microcrystalline wax E 905 were available, no ADI could be established. The Panel also concluded that the conservative exposure estimates to microcrystalline wax (E 905 from its use at maximum permitted level (following quantum satis rules, resulted in a sufficient margin of safety compared to the NOAEL established by the Panel for the closely related high viscosity mineral oils, and therefore the use microcrystalline wax (E 905 as a food additive with the currently authorised uses would not be of safety concern.

  10. The magnetic properties of powdered and compacted microcrystalline permalloy

    Science.gov (United States)

    Kollár, P.; Olekšáková, D.; Füzer, J.; Kováč, J.; Roth, S.; Polański, K.

    2007-03-01

    The aim of this work is to investigate the magnetic properties of powdered and compacted microcrystalline Ni-Fe (81 wt% of Ni) permalloy. It was found by investigating the influence of mechanical milling on the magnetic properties of powder samples prepared by milling of the ribbon that the alloy remains a solid solution with stable structure during the whole milling process. With decreasing particle size the rotation of magnetization vector gradually becomes dominant magnetization process and thus coercivity increases. After compaction of the powder by uniaxial hot pressing the magnetic contact between powder particles is recreated and for resulting bulk the displacement of the domain walls becomes dominant magnetization process with coercivity of 11 A/m (comparable with the coercivity of conventional permalloy).

  11. Dielectric barrier discharge plasma pretreatment on hydrolysis of microcrystalline cellulose

    Science.gov (United States)

    Fangmin, HUANG; Zhouyang, LONG; Sa, LIU; Zhenglong, Qin

    2017-04-01

    Dielectric barrier discharge (DBD) plasma was used as a pretreatment method for downstream hydrolysis of microcrystalline cellulose (MCC). The degree of polymerization (DP) of MCC decreased after it was pretreated by DBD plasma under a carrier gas of air/argon. The effectiveness of depolymerization was found to be influenced by the crystallinity of MCC when under the pretreatment of DBD plasma. With the addition of tert-butyl alcohol in the treated MCC water suspension solution, depolymerization effectiveness of MCC was inhibited. When MCC was pretreated by DBD plasma for 30 min, the total reducing sugar concentration (TRSC) and liquefaction yield (LY) of pretreated-MCC (PMCC) increased by 82.98% and 34.18% respectively compared with those for raw MCC.

  12. Dielectric barrier discharge plasma pretreatment on hydrolysis of microcrystalline cellulose

    Science.gov (United States)

    Huang, Fangmin; Long, Zhouyang; Liu, Sa; Qin, Zhenglong

    2017-04-01

    Dielectric barrier discharge (DBD) plasma was used as a pretreatment method for downstream hydrolysis of microcrystalline cellulose (MCC). The degree of polymerization (DP) of MCC decreased after it was pretreated by DBD plasma under a carrier gas of air/argon. The effectiveness of depolymerization was found to be influenced by the crystallinity of MCC when under the pretreatment of DBD plasma. With the addition of tert-butyl alcohol in the treated MCC water suspension solution, depolymerization effectiveness of MCC was inhibited. When MCC was pretreated by DBD plasma for 30 min, the total reducing sugar concentration (TRSC) and liquefaction yield (LY) of pretreated-MCC (PMCC) increased by 82.98% and 34.18% respectively compared with those for raw MCC.

  13. Silicone Rubber and Microcrystalline Cellulose Composites with Antimicrobial Properties

    Directory of Open Access Journals (Sweden)

    Virginija JANKAUSKAITĖ

    2014-04-01

    Full Text Available The goal of this study was to create polydimethylsiloxane (PDMS and microcrystalline cellulose (MCC composites with high mechanical properties and antimicrobial activity. Vinyl-terminated PDMS was mixed with bifunctional filler, which combines MCC stiffness and antimicrobial properties of silver nanoparticles. To provide antimicrobial properties the silver nanoparticles in situ were synthesized by chemical reducing method in MCC aqueous suspension. Silver nanoparticles (AgNPs concentration deposited on MCC particles surface was varied. The morphology, antimicrobial activity and mechanical properties of PDMS/MCC composites and their components have been investigated. It was shown that the combination of MCC/AgNPs as a filler and PDMS as matrix advantages bring multifunctional properties to polymer matrix composite. DOI: http://dx.doi.org/10.5755/j01.ms.20.1.4397

  14. Percutaneous microcrystalline chitosan application for sealing arterial puncture sites.

    Science.gov (United States)

    Hoekstra, A; Struszczyk, H; Kivekäs, O

    1998-08-01

    Arterial catheterization is one of the most frequently performed inpatient diagnostic and therapeutic procedures in the development countries. Complications may occur after any catheterization from inadequate hemostasis, particularly in the setting of aggressive anticoagulation. This study suggests that microcrystalline chitosan (MCCh) sealant installation via an arterial sheath at the completion of catheterization may improve hemostasis. Results using MCCh in eight heparinized dogs documented significant reductions in manual compression time (P = 0.016) of the artery after withdrawal of both the sheath introducer and catheter. Comparative results were found in rats, wherein a created wound in the aorta could be sealed relatively quickly and easily. The biodegradability, optimalization, and a better pharmaceutical formulation of this potential hemostatic agent require further studies.

  15. Device simulation and modeling of microcrystalline silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Takakura, H.; Hamakawa, Y. [Ritsumeikan Univ., Shiga (Japan). Dept. of Photonics

    2002-10-01

    Device modeling for p-i-n junction basis thin film microcrystalline Si solar cells has been examined with a simple model of columnar grain structure utilizing two-dimensional device simulator. The simulation results of solar cell characteristics show that open-circuit voltage (V{sub oc}) and fill factor considerably depend on structural parameters such as grain size and acceptor doping in intrinsic layer, while short-circuit current density (J{sub sc}) is comparatively stable by built-in electric field in the i-layer. It is also found that conversion efficiency of more than 16% could be expected with 1 {sup {mu}}m grain size and well-passivated condition with 10 {sup {mu}}m thick i-layer and optical confinement. (Author)

  16. Microcrystalline sodium tungsten bronze nanowire bundles as efficient visible light-responsive photocatalysts.

    Science.gov (United States)

    Wang, Lei; Zhan, Jinhua; Fan, Weiliu; Cui, Guanwei; Sun, Honggang; Zhuo, Linhai; Zhao, Xian; Tang, Bo

    2010-12-14

    Microcrystalline sodium tungsten bronze nanowire bundles were obtained via a facile hydrothermal synthesis, and were applied in water purification as visible-light-driven photocatalysts for the first time.

  17. Physicotechnical, spectroscopic and thermogravimetric properties of powdered cellulose and microcrystalline cellulose derived from groundnut shells

    OpenAIRE

    Chukwuemeka P. Azubuike; Jimson O. Odulaja; Augustine O Okhamafe

    2012-01-01

    α-Cellulose and microcrystalline cellulose powders, derived from agricultural waste products, that have for thepharmaceutical industry, desirable physical (flow) properties were investigated. α–Cellulose (GCN) wasextracted from groundnut shell (an agricultural waste product) using a non-dissolving method based oninorganic reagents. Modification of this α -cellulose was carried out by partially hydrolysing it with 2Nhydrochloric acid under reflux to obtain microcrystalline cellulose (MCGN). Th...

  18. Microcrystalline Cellulose from Plant Wastes through Sodium Hydroxide-Anthraquinone-Ethanol Pulping

    Directory of Open Access Journals (Sweden)

    Olugbenga Oludayo Oluwasina

    2014-08-01

    Full Text Available Microcrystalline cellulose was prepared from wastes of Tithonia diversifolia, inflorescence stems of Musa sapientum, and Musa paradisiaca by soda-anthraquinone–ethanol pulping method. They were bleached by sodium chlorite and then alpha-cellulose was isolated, followed by preparation of microcrystalline cellulose. The study revealed the effect of various processing stages on the properties of the cellulose obtained. Yields of more than 80% of microcrystalline cellulose were obtained. Fourier transform infrared (FTIR and solid state 13C Nuclear magnetic resonance (13C NMR confirmed the presence of the major expected peaks in microcrystalline cellulose. Scanning electron microscopy (SEM revealed that Musa species had short fiber length and mixtures of non-aggregated spherical, rod-shaped and thread like microcrystalline cellulose, but Tithonia diversifolia had aggregate crystal packed formation. The results compared well with those of other authors and were able to meet most of the requirements specified in British Pharmacopoeia. The study revealed that a drug excipient like microcrystalline cellulose that could protect thermo-labile active ingredients could be successfully obtained from abundant non-woody agricultural wastes.

  19. Photophysical Studies of a New Water Soluble Indocarbocyanine Dye Adsorbed onto Microcrystalline Cellulose and b-Cyclodextrin

    Directory of Open Access Journals (Sweden)

    Luis F. Vieira Ferreira

    2013-05-01

    Full Text Available A water-soluble indocarbocyanine dye was synthesized and its photophysics were studied for the first time on two solid hosts, microcrystalline cellulose and b-cyclodextrin, as well as in homogeneous media. The inclusion of the indocarbocyanine moiety onto microcrystalline cellulose increased the dye aggregation with both H and J aggregates being formed. Adsorption on b-cyclodextrin enhanced aggregation in a similar way. The fluorescence quantum yields were determined for the powdered samples of the cyanine dye on the two hosts and a significant increase was observed relative to homogeneous solution. A remarkable concentration dependence was also detected in both cases. A lifetime distribution analysis has shown that the indocarbocyanine dye mainly occupies the amorphous part of cellulose and is not entrapped in the crystalline part of this host. In the b-CD case, the adsorption occurs outside the host cavity. In both hosts a strong concentration quenching effect is observed and only monomers emit. Both adsorptions may be explained by stereochemical constraints imposed by the two long sulphoethyl tails linked to nitrogen atoms of the indocarbocyanine dye.

  20. n +-Microcrystalline-Silicon Tunnel Layer in Tandem Si-Based Thin Film Solar Cells

    Science.gov (United States)

    Lee, Ching-Ting; Lee, Hsin-Ying; Chen, Kuan-Hao

    2016-10-01

    In this study, the p-SiC/ i-Si/ n-Si cell and the p-SiC/ i-SiGe/ n-Si cell deposited using plasma-enhanced chemical vapor deposition were cascaded for forming the tandem Si-based thin film solar cells to absorb the wide solar spectrum. To further improve the performances of the tandem Si-based thin film solar cells, a 5-nm-thick n +-microcrystalline-Si ( n +-μc-Si) tunnel layer deposited using the laser-assisted plasma-enhanced chemical vapor deposition was inserted between the p-SiC/ i-Si/ n-Si cell and the p-SiC/ i-SiGe/ n-Si cell. Since both the plasma and the CO2 laser were simultaneously utilized to efficiently decompose the reactant and doping gases, the carrier concentration and the carrier mobility of the n +-μc-Si tunnel layer were significantly improved. The ohmic contact formed between the p-SiC layer and the n +-μc-Si tunnel layer with low resistance was beneficial to the generated current transportation and the carrier recombination rate. Therefore, the conversion efficiency of the tandem solar cells was promoted from 8.57% and 8.82% to 9.91% compared to that without tunnel layer and with 5-nm-thick n +-amorphous-Si tunnel layer.

  1. Processing pharmaceutical grade microcrystalline cellulose from groundnut husk: Extraction methods and characterization

    Directory of Open Access Journals (Sweden)

    Ohwoavworhua Frank

    2009-01-01

    Full Text Available Microcrystalline cellulose (MCC is an important ingredient in pharmaceutical, food, cosmetic and other industries. In this work, MCC was prepared from the alpha cellulose content of groundnut husk, a renewable natural resource that has no industrial utilization yet. The effects of pulping methods (sodium hydroxide and multistage pulping and varying bleaching time on yield and amorphous properties of obtained alpha cellulose were examined. The prepared MCC (groundnut husk-MCC was characterized using scanning electron microscopy (SEM, infrared spectroscopy (FTIR, X-ray powder diffractometer (X-RPD, differential scanning calorimetry (DSC and compared with commercial-grade MCC. The results showed that complete pulping was achieved only by the use of the multistage pulping method and its yield was 15%. It was also found that the duration of bleaching affected the polymeric form of the processed alpha cellulose and hence, it is suggested that X-ray diffraction analysis should form an in-process check in the production of cellulose to ensure batch-to-batch consistency and performance. It was concluded that GH-MCC compared favourably with the commercial-grade MCC as well as conform to official specifications for MCC in the British Pharmacopoeia.

  2. Phloxine B as a Probe for Entrapment in Microcrystalline Cellulose

    Directory of Open Access Journals (Sweden)

    Enrique San Román

    2012-02-01

    Full Text Available The photophysical behaviour of phloxine B adsorbed onto microcrystalline cellulose was evaluated by reflectance spectroscopy and laser induced time-resolved luminescence in the picosecond-nanosecond and microsecond-millisecond ranges. Analysis of the absorption spectral changes with concentration points to a small tendency of the dye to aggregate in the range of concentrations under study. Prompt fluorescence, phosphorescence and delayed fluorescence spectral decays were measured at room temperature and 77 K, without the need of sample degassing because cellulose protects triplet states from oxygen quenching. In all cases, spectral changes with time and lifetime distribution analysis were consistent with the dye coexisting in two different environments: dyes tightly entrapped between polymer chains in crystalline regions of cellulose showed longer fluorescence and phosphorescence lifetimes and more energetic triplet states, while dyes adsorbed in more amorphous regions of the support showed shorter lifetimes and less energetic triplet states. This behaviour is discussed in terms of the different dye-support interactions in both kinds of adsorption sites.

  3. Ambipolar characteristics of microcrystalline silicon thin-film transistors

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Kah-Yoong [IEF5-Photovoltaics, Research Center Juelich, 52425 Juelich (Germany); School of Engineering and Science, Jacobs University Bremen, 28759 Bremen (Germany); Faculty of Engineering, Multimedia University, 63100 Cyberjaya, Selangor (Malaysia); Gordijn, Aad [IEF5-Photovoltaics, Research Center Juelich, 52425 Juelich (Germany); Stiebig, Helmut [IEF5-Photovoltaics, Research Center Juelich, 52425 Juelich (Germany); Malibu GmbH and Co. KG, 33609 Bielefeld (Germany); Knipp, Dietmar [School of Engineering and Science, Jacobs University Bremen, 28759 Bremen (Germany)

    2010-04-15

    Hydrogenated microcrystalline silicon ({mu}c-Si:H) has recently attracted significant attention as a promising candidate for thin-film transistors (TFTs) in large-area electronics due to high electron and hole charge carrier mobilities. We report on top-gate ambipolar TFTs based on {mu}c-Si:H prepared by plasma-enhanced chemical vapor deposition at temperatures below 200 C. Electrons and holes are directly injected into the {mu}c-Si:H channel via chromium drain and source contacts. The TFTs exhibit electron and hole charge carrier mobilities of 30-50 cm{sup 2}/Vs and 10-15 cm{sup 2}/Vs, respectively. In this work, the electrical characteristics of the top-gate ambipolar {mu}c-Si:H TFTs are described by a simple analytical model that takes the ambipolar transport into account. The analytical expressions are used to model the transfer curves, the potential and the net surface charge along the channel of the TFTs. The electrical model provides insights into the electronic transport of ambipolar {mu}c-Si:H TFTs (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  4. Optical emission spectroscopy study on deposition process of microcrystalline silicon

    Institute of Scientific and Technical Information of China (English)

    Wu Zhi-Meng; Lei Qing-Song; Geng Xin-Hua; Zhao Ying; Sun Jian; Xi Jian-Ping

    2006-01-01

    This paper reports that the optical emission spectroscopy (OES) is used to monitor the plasma during the deposition process of hydrogenated microcrystalline silicon films in a very high frequency plasma enhanced chemical vapour deposition system. The OES intensities (SiH*, H*α and H*β) are investigated by varying the deposition parameters. The result shows that the discharge power, silane concentrations and substrate temperature affect the OES intensities. When the discharge power at silane concentration of 4% increases, the OES intensities increase first and then are constant, the intensities increase with the discharge power monotonously at silane concentration of 6%. The SiH* intensity increases with silane concentration, while the intensities of H*α and H*β increase first and then decrease. When the substrate temperature increases, the SiH* intensity decreases and the intensities of H*α and H*β are constant. The correlation between the intensity ratio of IH*α/ISiH* and the crystalline volume fraction (Xc) of films is confirmed.

  5. Electrical detection of spin coherence in microcrystalline pin solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Behrends, Jan [Hahn-Meitner-Institut Berlin, Abt. Silizium-Photovoltaik, Berlin (Germany); Department of Physics, University of Utah, Salt Lake City, UT (United States); Boehme, Christoph; Lips, Klaus [Hahn-Meitner-Institut Berlin, Abt. Silizium-Photovoltaik, Berlin (Germany); Haas, Stefan [Institute of Photovoltaics, Forschungszentrum Juelich, Juelich (Germany); Rech, Bernd [Hahn-Meitner-Institut Berlin, Abt. Silizium-Photovoltaik, Berlin (Germany); Institute of Photovoltaics, Forschungszentrum Juelich, Juelich (Germany)

    2007-07-01

    Defects in the band gap of hydrogenated microcrystalline silicon ({mu}cSi:H) pin solar cells, even at low concentrations, can act as recombination centres and thus, they can influence the electronic properties of the device significantly. A powerful technique to investigate these recombination processes is pulsed electrically detected magnetic resonance (pEDMR). This method is based on transient photocurrent measurements after varying specific recombination or transport rates and reveals information about the microscopic mechanisms of recombination and transport that involve paramagnetic states. In this study we report on the application of pEDMR on state-of-the-art {mu}c-Si:H pin solar cells prepared on ZnO coated glass. An adapted contact structure allows the observation of Rabi oscillations in the photocurrent at low temperatures (T=10 K) reflecting coherent spin motion. The coherence time is found to be on the order of several hundred nanoseconds and is determined by recombination. A Fourier analysis of the observed Rabi oscillations allows a distinction between the involved recombination processes. A discussion on the different recombination mechanisms in {mu}c-Si:H cells is given.

  6. Non-wood fibre production of microcrystalline cellulose from Sorghum caudatum: Characterisation and tableting properties

    OpenAIRE

    Ohwoavworhua F; Adelakun T

    2010-01-01

    The microcrystalline cellulose is an important ingredient in pharmaceutical, food, cosmetic and other industries. In this study, the microcrystalline cellulose, obtained from the stalk of Sorghum caudatum was evaluated for its physical and tableting characteristics with a view to assessing its usefulness in pharmaceutical tableting. The microcrystalline cellulose, obtained from the stalk of Sorghum caudatum, obtained by sodium hydroxide delignification followed by sodium hypochlorite bleachin...

  7. Application of ethyl cellulose, microcrystalline cellulose and octadecanol for wax based floating solid dispersion pellets.

    Science.gov (United States)

    Yan, Hong-Xiang; Zhang, Shuang-Shuang; He, Jian-Hua; Liu, Jian-Ping

    2016-09-01

    The present study aimed to develop and optimize the wax based floating sustained-release dispersion pellets for a weakly acidic hydrophilic drug protocatechuic acid to achieve prolonged gastric residence time and improved bioavailability. This low-density drug delivery system consisted of octadecanol/microcrystalline cellulose mixture matrix pellet cores prepared by extrusion-spheronization technique, coated with drug/ethyl cellulose 100cp solid dispersion using single-step fluid-bed coating method. The formulation-optimized pellets could maintain excellent floating state without lag time and sustain the drug release efficiently for 12h based on non-Fickian transport mechanism. Observed by SEM, the optimized pellet was the dispersion-layered spherical structure containing a compact inner core. DSC, XRD and FTIR analysis revealed drug was uniformly dispersed in the amorphous molecule form and had no significant physicochemical interactions with the polymer dispersion carrier. The stability study of the resultant pellets further proved the rationality and integrity of the developed formulation.

  8. The effect of wax on compaction of microcrystalline cellulose beads made by extrusion and spheronization.

    Science.gov (United States)

    Iloañusi, N O; Schwartz, J B

    1998-01-01

    The effect of wax on the deformation behavior and compression characteristics of microcrystalline cellulose (Avicel PH-101) and acetaminophen (APAP) beads is described. Beads of Avicel PH-101 and APAP formulations were prepared using extrusion and spheronization technology. A waxy material, glyceryl behenate, N.F. (Compritol), was added to the formulations in amounts ranging from 10% to 70% of total solid weight. Beads with a selected particle size range of 16-30 mesh were compressed with an instrumented single punch Manesty F press utilizing a 7/16-in. flat-faced tooling set. Compaction profiles were generated for the tablets to evaluate the effect of wax on the densification of beads containing wax. Beads made without wax (the control formulation) required greater compression forces to form cohesive tablets. As the amount of wax in the bead formulation was increased, the beads become more plastic and compressible. The Heckel equation which relates densification to compression pressure was used to evaluate the deformation mechanisms of the bead formulations. The analysis shows that as the level of wax in the bead formulation is increased, the yield pressure decreases, indicating that the beads densify by a plastic deformation mechanism.

  9. The rheological properties of modified microcrystalline cellulose containing high levels of model drugs.

    Science.gov (United States)

    Knight, Paul E; Podczeck, Fridrun; Newton, J Michael

    2009-06-01

    The rheological properties of different types of microcrystalline cellulose (MCC) mixed with model drugs and water have been evaluated to identify the influence of sodium carboxymethylcellulose (SCMC) added to the cellulose during preparation. A ram extruder was used as a capillary rheometer. The mixtures consisted of 20% spheronizing agent (standard grade MCC or modified types with 6% or 8% of low viscosity grade SCMC) and 80% of ascorbic acid, ibuprofen or lactose monohydrate. The introduction of SCMC changed all rheological parameters assessed. It produced more rigid systems, requiring more stress to induce and maintain flow. Degree of non-Newtonian flow, angle of convergence, extensional viscosity, yield and die land shear stress at zero velocity, and static wall friction were increased, but recoverable shear and compliance were decreased. The presence of SCMC did not remove the influence of the type of drug. The mixture of ibuprofen and standard MCC had the lowest values for shear stress as a function of the rate of shear, extensional viscosity, and angle of convergence, but the highest values for recoverable shear and compliance. The findings indicate that the system has insufficient rigidity to form pellets.

  10. The microstructure evolution of hydrogenated microcrystalline germanium promoted by power gradient method

    Science.gov (United States)

    Wang, Xinyu; Ni, Jian; Li, Chang; Sun, Xiaoxiang; Li, Zhenglong; Cai, Hongkun; Li, Juan; Zhang, Jianjun

    2016-12-01

    This paper studies the microstructure evolution of hydrogenated microcrystalline germanium (μc-Ge:H) thin films deposited by plasma enhanced chemical vapor deposition (PECVD). There is an amorphous incubation layer formed in the initial deposition stage of μc-Ge:H thin film. It is demonstrated that the thickness of incubation layer can be reduced by high hydrogen dilution and high discharge power method. However, at high hydrogen dilution, the deposition rate of μc-Ge:H appears a sharply decrease. Using a high discharge power can compensate the deposition rate decrease but lead to decrease of average grain size and appearance of micro-void in the μc-Ge:H thin film. In addition, by comparing two thickness groups of μc-Ge:H thin films deposited at different discharge powers, it is noticed that the evolution process relates to the formation of crystal nucleuses. Thus, a power gradient method is proposed to understand the mechanism of nucleation and crystal growth in the initial deposition process of μc-Ge:H films. Finally, by power gradient method, the incubation layer thickness of μc-Ge:H thin films has been decreased to less than 6 nm. Moreover, Raman scattering spectra shows a 38 nm μc-Ge:H film has a crystal fraction (XC) of 62.4%. Meanwhile, the mobility of TFT devices shows the improved electrical property of μc-Ge:H film deposited by power gradient method.

  11. Characterization of microcrystalline I-layer for solar cells prepared in low temperature - plastic compatible process

    KAUST Repository

    Sliz, Rafal

    2012-06-01

    Microcrystalline silicon (mc-Si) lms deposited using a Plasma Enhanced Chemical Vapour Deposition (PECVD) process constitute an important material for manufacturing low-cost, large-area thin-lm devices, such as solar cells or thin-lm transistors. Although the deposition of electronic-grade mc-Si using the PECVD process is now well established, the high substrate temperature required (~400°C) does not lend itself to electronic devices with exible form factors fabricated on low-cost plastic substrates. In this study, we rst investigated an intrinsic mc-Si layer deposited at plastic-compatible substrate temperatures (~150°C) by characterising the properties of the lm and then evaluated its applicability to p-i-n solar cells though device characterisation. When the performance of the solar cell was correlated with lm properties, it was found that, although it compared unfavourably with mc-Si deposited at higher temperatures, it remained a very promising option. Nonetheless, further development is required to increase the overall eciency of mc-Si exible solar cells.

  12. Formulation of ranitidine pellets by extrusion-spheronization with little or no microcrystalline cellulose.

    Science.gov (United States)

    Basit, A W; Newton, J M; Lacey, L F

    1999-01-01

    The present study was concerned with the feasibility of formulating ranitidine into pellets with a range of alternative excipients in place of microcrystalline cellulose (MCC). Eight ranitidine formulations employing two or more of the excipients lactose, barium sulfate, glyceryl monostearate, and MCC were processed by extrusion-spheronization, and characterized according to a series of physico-mechanical and dissolution criteria. Formulations containing lactose produced unsatisfactory pellets of wide size distribution and irregular shape, whereas formulations incorporating barium sulfate and glyceryl monostearate with or without MCC resulted in relatively spherical pellets of narrow size distribution and good mechanical properties. Ranitidine release was found to be rapid and virtually complete within 15 min, regardless of the pellet formulation. A direct relationship was observed between the concentration of MCC in the formulation and the properties of the pellets. In general, the higher the concentration of MCC, the rounder, stronger, and less friable the pellets. However, even pellets without MCC were also successfully prepared with a superior size distribution and shape over those with MCC. Overall, these results confirm that ranitidine can be formulated into pellet dosage forms with little or no MCC by the extrusion-spheronization process.

  13. Evaluation of several microcrystalline celluloses obtained from agricultural by-products

    Directory of Open Access Journals (Sweden)

    John Rojas

    2011-01-01

    Full Text Available Microcrystalline cellulose (MCCI has been widely used as an excipient for direct compression due to its good flowability, compressibility, and compactibility. In this study, MCCI was obtained from agricultural by-products, such as corn cob, sugar cane bagasse, rice husk, and cotton by pursuing acid hydrolysis, neutralization, clarification, and drying steps. Further, infrared spectroscopy (IR, X-ray diffraction (XRD, optical microscopy, degree of polymerization (DP, and powder and tableting properties were evaluated and compared to those of Avicel PH101, Avicel PH102, and Avicel PH200. Except for the commercial products, all materials showed a DP from 55 to 97. Particles of commercial products and corn cob had an irregular shape, whereas bagasse particles were elongated and thick. Rice and cotton particles exhibited a flake-like and fiber-like shape, respectively. MCCI as obtained from rice husk and cotton was the most densified material, while that produced from corn cob and bagasse was bulky, porous, and more compressible. All products had a moisture content of less than 10% and yields from 7.4% to 60.4%. MCCI as obtained from bagasse was the most porous and compressible material among all materials. This product also showed the best tableting properties along with Avicel products. Likewise, all MCCI products obtained from the above-mentioned sources showed a more rapid disintegration time than that of Avicel products. These materials can be used as a potential source of MCCI in the production of solid dosage forms.

  14. Evaluation of several microcrystalline celluloses obtained from agricultural by-products.

    Science.gov (United States)

    Rojas, John; Lopez, Alvin; Guisao, Santiago; Ortiz, Carlos

    2011-07-01

    Microcrystalline cellulose (MCCI) has been widely used as an excipient for direct compression due to its good flowability, compressibility, and compactibility. In this study, MCCI was obtained from agricultural by-products, such as corn cob, sugar cane bagasse, rice husk, and cotton by pursuing acid hydrolysis, neutralization, clarification, and drying steps. Further, infrared spectroscopy (IR), X-ray diffraction (XRD), optical microscopy, degree of polymerization (DP), and powder and tableting properties were evaluated and compared to those of Avicel PH101, Avicel PH102, and Avicel PH200. Except for the commercial products, all materials showed a DP from 55 to 97. Particles of commercial products and corn cob had an irregular shape, whereas bagasse particles were elongated and thick. Rice and cotton particles exhibited a flake-like and fiber-like shape, respectively. MCCI as obtained from rice husk and cotton was the most densified material, while that produced from corn cob and bagasse was bulky, porous, and more compressible. All products had a moisture content of less than 10% and yields from 7.4% to 60.4%. MCCI as obtained from bagasse was the most porous and compressible material among all materials. This product also showed the best tableting properties along with Avicel products. Likewise, all MCCI products obtained from the above-mentioned sources showed a more rapid disintegration time than that of Avicel products. These materials can be used as a potential source of MCCI in the production of solid dosage forms.

  15. Direct observation and mechanism of increased emission sites in Fe-coated microcrystalline diamond films

    Energy Technology Data Exchange (ETDEWEB)

    Panda, Kalpataru; Sundaravel, B.; Panigrahi, B. K. [Materials Physics Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Huang, Pin-Chang; Shih, Wen-Ching [Graduate Institute in Electro-Optical Engineering, Tatung University, Taipei 104, Taiwan (China); Chen, Huang-Chin; Lin, I-Nan [Department of Physics, Tamkang University, New-Taipei 251, Taiwan (China)

    2012-06-15

    The electron field emission (EFE) properties of microcrystalline diamond (MCD) films are significantly enhanced due to the Fe coating and post-annealing processes. The 900 Degree-Sign C post-annealed Fe coated diamond films exhibit the best EFE properties, with a turn on field (E{sub 0}) of 3.42 V/{mu}m and attain EFE current density (J{sub e}) of 170 {mu}A/cm{sup 2} at 7.5 V/{mu}m. Scanning tunnelling spectroscopy (STS) in current imaging tunnelling spectroscopy mode clearly shows the increased number density of emission sites in Fe-coated and post-annealed MCD films than the as-prepared ones. Emission is seen from the boundaries of the Fe (or Fe{sub 3}C) nanoparticles formed during the annealing process. In STS measurement, the normalized conductance (dI/dV/I/V) versus V curves indicate nearly metallic band gap, at the boundaries of Fe (or Fe{sub 3}C) nanoparticles. Microstructural analysis indicates that the mechanism for improved EFE properties is due to the formation of nanographite that surrounds the Fe (or Fe{sub 3}C) nanoparticles.

  16. Small-angle x-ray scattering study on the structure of microcrystalline and nanofibrillated cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Leppaenen, Kirsi; Pirkkalainen, Kari; Penttilae, Paavo; Serimaa, Ritva [Division of Materials Physics, Department of Physics, P.O.B. 64, FI-00014 University of Helsinki (Finland); Sievaenen, Jenni [VTT, Espoo (Finland); Kotelnikova, Nina, E-mail: kirsi.leppanen@helsinki.f [Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoy pr. 31, St. Petersburg 199004 (Russian Federation)

    2010-10-01

    The effects of different solvents on the structure of microcrystalline and nanofibrillated cellulose (MCC, NFC) were studied using small-angle x-ray scattering (SAXS). MCC was immersed in water, ethanol, and acetone, and NFC was immersed only in water and ethanol, but studied also in the form of foam-like water-NFC-gel in wet, air-dried and re-wet states. The solvent affected the average chord length, which reveals the typical length scale of the structure of the sample: 2.4 {+-} 0.1 nm was obtained for MCC-water, 2.5 {+-} 0.1 nm for re-wet NFC-gel, 1.6 {+-} 0.1 nm for MCC-ethanol, 1.2 {+-} 0.1 nm for NFC-ethanol, and 1.3 {+-} 0.1 nm for MCC-acetone. The specific surface of cellulose increased strongly when MCC and NFC were immersed in the solvents compared to dry cellulose. The specific surface of cellulose was determined to be larger for NFC-water than MCC-water, and slightly larger for dry NFC powder than for dry MCC, which can be explained by the fact that the width of cellulose crystallites perpendicular to the cellulose chain direction was slightly larger in MCC than in NFC on the basis of wide-angle x-ray scattering results.

  17. Diagenetic Microcrystalline Opal Varieties from the Monterey Formation, CA: HRTEM Study of Structures and Phase Transformation Mechanisms

    Science.gov (United States)

    Cady, Sherry L.; Wenk, H.-R.; DeVincenzi, Don (Technical Monitor)

    1994-01-01

    Microcrystalline opal varieties form as intermediary precipitates during the diagenetic transformation of biogenically precipitated non-crystalline opal (opal-A) to microquartz. With regard to the Monterey Formation of California, X-ray powder diffraction studies have shown that a decrease in the primary d-spacing of opal-CT toward that of cristobalite occurs with increasing diagenesis. The initial timing of opal-CT/quartz formation and the value of the primary opal-CT d-spacing, are influenced by the sediment. lithology. Transmission electron microscopy methods (CTEM/HRTEM) were used to investigate the structure of the diagenetic phases and establish transformation mechanisms between the varieties of microcrystalline opals in charts and porcelanites from the Monterey Formation. HRTEM images revealed that the most common fibrous varieties of microcrystalline opals contain varying amounts of structural disorder. Finite lamellar units of cristobalite-and tridymite-type. layer sequences were found to be randomly stacked in a direction perpendicular to the fiber axis. Disordered and ordered fibers were found to have coprecipitated within the same radial fiber bundles that formed within the matrix of the Most siliceous samples. HRTEM images, which reveal that the fibers within radial and lepispheric fiber bundles branch non-crystallographically, support an earlier proposal that microspheres in chert grow via a spherulitic growth mechanism. A less common variety of opal-CT was found to be characterized by non-parallel (low-angle) stacking sequences that often contain twinned lamellae. Tabular-shaped crystals of orthorhombic tridymite (PO-2) were also identified in the porcelanite samples. A shift in the primary d-spacing of opal-CT has been interpreted as an indication of solid-state ordering g toward a predominantly cristobalite structure, (opal-C). Domains of opal-C were identified as topotactically-oriented overgrowths on discrete Sections of opal-CT fibers and as

  18. Fractal analysis of SEM images and mercury intrusion porosimetry data for the microstructural characterization of microcrystalline cellulose-based pellets

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Carracedo, A.; Alvarez-Lorenzo, C.; Coca, R.; Martinez-Pacheco, R.; Concheiro, A. [Departamento de Farmacia y Tecnologia Farmaceutica, Universidad de Santiago de Compostela, Santiago de Compostela 15782 (Spain); Gomez-Amoza, J.L. [Departamento de Farmacia y Tecnologia Farmaceutica, Universidad de Santiago de Compostela, Santiago de Compostela 15782 (Spain)], E-mail: joseluis.gomez.amoza@usc.es

    2009-01-15

    The microstructure of theophylline pellets prepared from microcrystalline cellulose, carbopol and dicalcium phosphate dihydrate, according to a mixture design, was characterized using textural analysis of gray-level scanning electron microscopy (SEM) images and thermodynamic analysis of the cumulative pore volume distribution obtained by mercury intrusion porosimetry. Surface roughness evaluated in terms of gray-level non-uniformity and fractal dimension of pellet surface depended on agglomeration phenomena during extrusion/spheronization. Pores at the surface, mainly 1-15 {mu}m in diameter, determined both the mechanism and the rate of theophylline release, and a strong negative correlation between the fractal geometry and the b parameter of the Weibull function was found for pellets containing >60% carbopol. Theophylline mean dissolution time from these pellets was about two to four times greater. Textural analysis of SEM micrographs and fractal analysis of mercury intrusion data are complementary techniques that enable complete characterization of multiparticulate drug dosage forms.

  19. Phase Transformation and Enhancing Electron Field Emission Properties in Microcrystalline Diamond Films Induced by Cu Ion Implantation and Rapid Annealing

    Institute of Scientific and Technical Information of China (English)

    Yan-Yan Shen; Yi-Xin Zhang; Ting Qi; Yu Qiao; Yu-Xin Jia; Hong-Jun Hei; Zhi-Yong He

    2016-01-01

    Cu ion implantation and subsequent rapid annealing at 500℃ in N2 result in low surface resistivity of 1.611 ohm/sq with high mobility of 290 cm2 V-1 S-1 for microcrystalline diamond (MCD) films.Its electrical field emission behavior can be turned on at Eo =2.6 V/μm,attaining a current density of 19.5μA/cm2 at an applied field of 3.5 V/μm.Field emission scanning electron microscopy combined with Raman and x-ray photoelectron microscopy reveal that the formation of Cu nanoparticles in MCD films can catalytically convert the less conducting disorder/a-C phases into graphitic phases and can provoke the formation of nanographite in the films,forming conduction channels for electron transportation.

  20. Matrix mini-tablets based on starch/microcrystalline wax mixtures.

    Science.gov (United States)

    De Brabander, C; Vervaet, C; Fiermans, L; Remon, J P

    2000-04-20

    Matrix mini-tablets based on a combination of microcrystalline waxes and starch derivatives were prepared using ibuprofen as a model drug. The production of mini-tablets was preferred over the production of pellets, as up-scaling of the pelletisation process seemed problematic. Prior to tabletting, melt granulation in a hot stage screw extruder and milling were required. The in vitro drug release was varied using microcrystalline waxes with a different melting range, the slowest drug release being obtained with a formulation containing a microcrystalline wax with a melting range between 68 and 72 degrees C. Generally speaking increasing the wax concentration resulted in a slower drug release. In vitro drug release profiles were also modified using different starches and mixtures of starches. Increasing the ibuprofen concentration to 70% resulted in a faster drug release rate.

  1. High deposition rate processes for the fabrication of microcrystalline silicon thin films

    Energy Technology Data Exchange (ETDEWEB)

    Michard, S. [Institute of Energy and Climate Research 5 - Photovoltaik, Forschungszentrum Jülich, 52425 Jülich (Germany); Meier, M., E-mail: ma.meier@fz-juelich.de [Institute of Energy and Climate Research 5 - Photovoltaik, Forschungszentrum Jülich, 52425 Jülich (Germany); Grootoonk, B.; Astakhov, O.; Gordijn, A.; Finger, F. [Institute of Energy and Climate Research 5 - Photovoltaik, Forschungszentrum Jülich, 52425 Jülich (Germany)

    2013-05-15

    The increase of deposition rate of microcrystalline silicon absorber layers is an essential point for cost reduction in the mass production of thin-film silicon solar cells. In this work we explored a broad range of plasma enhanced chemical vapor deposition (PECVD) parameters in order to increase the deposition rate of intrinsic microcrystalline silicon layers keeping the industrial relevant material quality standards. We combined plasma excitation frequencies in the VHF band with the high pressure high power depletion regime using new deposition facilities and achieved deposition rates as high as 2.8 nm/s. The material quality evaluated from photosensitivity and electron spin resonance measurements is similar to standard microcrystalline silicon deposited at low growth rates. The influence of the deposition power and the deposition pressure on the electrical and structural film properties was investigated.

  2. Preparation and Characterization of Microcrystalline Cellulose (MCC from Kenaf and Cotton Stem

    Directory of Open Access Journals (Sweden)

    Farshad Mirehki

    2013-11-01

    Full Text Available Cellulose, microcrystalline cellulose (MCC and nanofiber cellulose are the ones of materials which are being used recently as biodegradable filler and reinforcing agent for making composites. In this research, microcrystalline cellulose were prepared from kenaf and cotton bast by hydrochloric acid hydrolysis. The effects of hydrolysis condition on amount of crystallinity and crystal size of MCC were investigated by infrared spectroscopy (FT-IR, X-ray diffraction (XRD and scanning electron microscopy (SEM. Results have shown that in both samples increasing the acid ratio increased the crystallinity; however, the size of crystals did not change. SEM results have shown that after hydrolysis the size of sample particles was micro.

  3. Microcrystalline silicon films and solar cells investigatet by photoluminescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Merdzhanova, T.

    2005-07-01

    A systematic investigation on photoluminescence (PL) properties of microcrystalline silicon ({mu}c-Si:H) films with structural composition changing from highly crystalline to predominantly amorphous is presented. The samples were prepared by PECVD and HWCVD with different silane concentration in hydrogen (SC). By using photoluminescence in combination with Raman spectroscopy the relationship between electronic properties and the microstructure of the material is studied. The PL spectra of {mu}c-Si:H reveal a rather broad ({proportional_to}0.13 eV) featureless band at about 1 eV ('{mu}c'-Si-band). In mixed phase material of crystalline and amorphous regions, a band at about 1.3 eV with halfwidth of about 0.3 eV is found in addition to '{mu}c'-Si-band, which is attributed to the amorphous phase ('a'-Si-band). Similarly to amorphous silicon, the '{mu}c'-Si-band is assigned to recombination between electrons and holes in band tail states. An additional PL band centred at about 0.7 eV with halfwidth slightly broader than the '{mu}c'-Si-band is observed only for films prepared at high substrate temperature and it is preliminarily assigned to defect-related transitions as in polycrystalline silicon. With decreasing crystalline volume fraction, the '{mu}c'-Si-band shifts continuously to higher energies for all {mu}c-Si:H films but the linewidth of the PL spectra is almost unaffected. This is valid for all deposition conditions investigated. The results are interpreted, assuming decrease of the density of band tail states with decreasing crystalline volume fraction. A simple model is proposed to simulate PL spectra and V{sub oc} in {mu}c-Si:H solar cells as a function of temperature, based on carrier distributions in quasi-equilibrium conditions. In the model is assumed symmetric density of states distributions for electrons and holes in the conduction and the valence band tail states. The best agreement between

  4. Electron spin resonance and transient photocurrent measurements on microcrystalline silicon

    Energy Technology Data Exchange (ETDEWEB)

    Dylla, T.

    2004-09-01

    The electronic properties of microcrystalline silicon ({mu}c-Si:H) films have been studied using electron spin resonance (ESR), transient photocurrent time-of-flight (TOF) techniques, and electrical conductivity measurements. Structural properties were determined by Raman spectroscopy. A wide range of structure compositions, from highly crystalline films with no discernable amorphous content, to predominantly amorphous films with no crystalline phase contributions, was investigated. Models and possible explanations concerning the nature and energetic distribution of electronic defects as a function of film composition are discussed. It is shown that the spin density N{sub S} in {mu}c-Si:H films is linked strongly to the structure composition of the material. Both reversible and irreversible changes in the ESR signal and dark conductivity due to atmospheric effects are found in {mu}c-Si:H. The porous structure of highly crystalline material facilitates in-diffusion of atmospheric gases, which strongly affects the character and/or density of surface states. Two contributing processes have been identified, namely adsorption and oxidation. Both processes lead to an increase of N{sub S}. Measurements on n-type {mu}c-Si:H films were used as a probe of the density of gap states, confirming that the spin density NS is related to the density of defects. The results confirm that for a wide range of structural compositions, the doping induced Fermi level shift in {mu}c-Si:H is governed by compensation of defect states, for doping concentrations up to the dangling bond spin density. At higher concentrations a doping efficiency close to unity was found, confirming that in {mu}c-Si:H the measured spin densities represent the majority of gap states (N{sub S}=N{sub DB}). By applying the TOF technique to study pin solar cells based on {mu}c-Si:H, conclusive hole drift mobility data were obtained. Despite the predominant crystallinity of these samples, the temperature-dependence of

  5. A novel method of producing a microcrystalline beta-sitosterol suspension in oil

    DEFF Research Database (Denmark)

    Christiansen, Leena I; Rantanen, Jukka T; von Bonsdorff, Anna K

    2002-01-01

    This paper describes a novel method of producing a microcrystalline oral suspension containing beta-sitosterol in oil for the treatment of hypercholesterolaemia. beta-Sitosterol pseudopolymorphs with different water contents were crystallized from acetone and acetone-water solutions. Structural a...

  6. Optimisation of the composition and production of mannitol/microcrystalline cellulose tablets

    NARCIS (Netherlands)

    Westerhuis, J.A; de Haan, P; Zwinkels, J; Jansen, W.T; Coenegracht, P.M J; Lerk, C.F

    1996-01-01

    Mixtures of mannitol and microcrystalline cellulose (MCC) were investigated on a small-production scale by granulation in a high-shear mixer and compression into tablets. For both excipients only a few cases of incompatibilities with active ingredients are known. Tablets with only MCC as the filler

  7. Visible light activated TiO2/microcrystalline cellulose nanocatalyst to destroy organic contaminants in water.

    Science.gov (United States)

    Hybrid TiO2/microcrystalline cellulose (MC) nanophotocatalyst was prepared in situ by a facile and simple synthesis utilizing benign precursors such as MC and TiCl4. The as-prepared nanocomposite was characterized by XRD, XPS, BET surface area analyzer, UV–vis DRS and TGA. Surfac...

  8. Development of Doped Microcrystalline Silicon Oxide and its Application to Thin‑Film Silicon Solar Cells

    NARCIS (Netherlands)

    Lambertz, A.

    2015-01-01

    The aim of the present study is the development of doped microcrystalline silicon oxide (µc‑SiOx:H) alloys and its application in thin‑film silicon solar cells. The doped µc‑SiOx:H material was prepared from carbon dioxide (CO2), silane (SiH4), hydrogen (H2) gas mixtures using plasma enhanced

  9. Conventional and 360 degree electron tomography of a micro-crystalline silicon solar cell

    DEFF Research Database (Denmark)

    Duchamp, Martial; Ramar, Amuthan; Kovács, András

    2011-01-01

    Bright-field (BF) and annular dark-field (ADF) electron tomography in the transmission electron microscope (TEM) are used to characterize elongated porous regions or cracks (simply referred to as cracks thereafter) in micro-crystalline silicon (μc-Si:H) solar cell. The limitations of inferring...

  10. Defect structure and mechanical stability of microcrystalline titanium produced by equal channel angular pressing

    Science.gov (United States)

    Betekhtin, V. I.; Kadomtsev, A. G.; Narykova, M. V.; Amosova, O. V.; Sklenicka, V.

    2017-01-01

    It is established that increases in nanoporosity and the proportion of high-angle grain boundaries in the process of equal-channel angular pressing are the main structural factors leading to reduction in mechanical stability (durability) of microcrystalline titanium during long-term tests under creeping conditions.

  11. Visible light activated TiO2/microcrystalline cellulose nanocatalyst to destroy organic contaminants in water.

    Science.gov (United States)

    Hybrid TiO2/microcrystalline cellulose (MC) nanophotocatalyst was prepared in situ by a facile and simple synthesis utilizing benign precursors such as MC and TiCl4. The as-prepared nanocomposite was characterized by XRD, XPS, BET surface area analyzer, UV–vis DRS and TGA. Surfac...

  12. Development of Doped Microcrystalline Silicon Oxide and its Application to Thin‑Film Silicon Solar Cells

    NARCIS (Netherlands)

    Lambertz, A.

    2015-01-01

    The aim of the present study is the development of doped microcrystalline silicon oxide (µc‑SiOx:H) alloys and its application in thin‑film silicon solar cells. The doped µc‑SiOx:H material was prepared from carbon dioxide (CO2), silane (SiH4), hydrogen (H2) gas mixtures using plasma enhanced chemic

  13. The statistical shift of the chemical potential causing anomalous conductivity in hydrogenated microcrystalline silicon

    NARCIS (Netherlands)

    Lof, R.W.; Schropp, R.E.I.

    2010-01-01

    The behavior of the electrical conductivity in hydrogenated microcrystalline silicon (μ c-Si:H) that is frequently observed is explained by considering the statistical shift in the chemical potential as a function of the crystalline fraction (Xc), the dangling bond density (N db), and the doping den

  14. Supramolecular elucidation of the quality attributes of microcrystalline cellulose and isomalt composite pellet cores.

    Science.gov (United States)

    Antal, István; Kállai, Nikolett; Luhn, Oliver; Bernard, Jörg; Nagy, Zsombor Kristóf; Szabó, Barnabás; Klebovich, Imre; Zelkó, Romána

    2013-10-01

    The major objective of this study was to disclose the relationships between the physical quality attributes and supramolecular structure of novel composite pellet cores containing microcrystalline cellulose (MCC) and isomalt in different ratios. The novel composite pellet cores were manufactured by an extrusion/spheronisation process. The micro or supramolecular structure of pellets was tracked by positron annihilation lifetime spectroscopy (PALS) based on the o-Ps lifetime values. The results indicate a correlation between the examined macro and microstructural properties of the inert cores. The higher free volume holes indicated by the higher o-Ps lifetime values resulted in a more mobile micro- and supramolecular structure of MCC cores thus increasing the plastic deformation and the tensile strength of the cores. A physical interaction was found between the microcrystalline cellulose and isomalt which supports the osmotic effect of the water soluble sugar alcohol in the composite pellet cores regarding drug release.

  15. Microwave assisted conversion of microcrystalline cellulose into value added chemicals using dilute acid catalyst.

    Science.gov (United States)

    Ching, Teck Wei; Haritos, Victoria; Tanksale, Akshat

    2017-02-10

    One of the grand challenges of this century is to transition fuels and chemicals production derived from fossil feedstocks to renewable feedstocks such as cellulosic biomass. Here we describe fast microwave conversion of microcrystalline cellulose (MCC) in water, with dilute acid catalyst to produce valuable platform chemicals. Single 10min microwave assisted treatment was able to convert >60% of MCC, with >50mol% yield of desirable products such as glucose, HMF, furfural and levulinic acid. Recycling of residual MCC with make-up fresh MCC resulted in an overall conversion of >93% after 5 cycles while maintaining >60% conversion in each cycle. Addition of isopropanol (70%v/v) as a co-solvent increased the yields of HMF and levulinic acid. This work shows for the first time proof of concept for complete conversion of recalcitrant microcrystalline cellulose in mild conditions of low temperature, dilute acid and short residence time using energy efficient microwave technology.

  16. Study on Preconcentration of Trace Copper Using Microcrystalline Triphenylmethane Loaded with Malachite Green

    Institute of Scientific and Technical Information of China (English)

    LIANG,Yong; ZHAO,Xiao-Hong; LI,Quan-Min; CUI,Feng-Ling; LIU,Guo-Guang

    2007-01-01

    The paper describes a noveI method for copper preconcentration using microcrystalline triphenylmethane loaded with malachite green prior to the determination by the flame atomic absorption spectrometry(FAAS).Under the optimum conditions,Cu(Ⅱ)can be totally adsorbed on the surface of microcrystalline triphenylmethane,and completely separated from Pb(Ⅱ),Cd(Ⅱ),Co(Ⅱ),Cr(Ⅲ),Ni(Ⅱ),Mn(Ⅱ),Fe(Ⅲ)and Al(Ⅲ)by controlling acidity.The preconcentration factor of this proposed method is 200.The recovery is in a range of 97.5%-105%.The relative standard deviation(RSD)is not beyond 3.0%.The proposed method has been successfully applied to the determination of trace copper in various water samples with satisfactory results.

  17. A fast method to diagnose phase transition from amorphous to microcrystalline silicon

    Institute of Scientific and Technical Information of China (English)

    HOU; GuoFu

    2007-01-01

    A series of hydrogenated silicon thin films were prepared by the radio frequency plasma enhanced chemical vapor deposition method (RF-PECVD) with various silane concentrations. The influence of silane concentration on structural and electrical characteristics of these films was investigated to study the phase transition region from amorphous to microcrystalline phase. At the same time, optical emission spectra (OES) from the plasma during the deposition process were monitored to get information about the plasma properties, Raman spectra were measured to study the structural characteristics of the deposited films. The combinatorial analysis of OES and Raman spectra results demonstrated that the OES can be used as a fast method to diagnose phase transition from amorphous to microcrystalline silicon. At last the physical mechanism, why both OES and Raman can be used to diagnose the phase transition, was analyzed theoretically.……

  18. Triplet excitons as sensitive spin probes for structure analysis of extended defects in microcrystalline silicon

    Science.gov (United States)

    Meier, Christoph; Teutloff, Christian; Behrends, Jan; Bittl, Robert; Astakhov, Oleksandr; Lips, Klaus

    2016-07-01

    Electrically detected magnetic resonance (EDMR) spectroscopy is employed to study the influence of triplet excitons on the photocurrent in state-of-the-art microcrystalline silicon thin-film solar cells. These triplet excitons are used as sensitive spin probes for the investigation of their electronic and nuclear environment in this mixed-phase material. According to low-temperature EDMR results obtained from solar cells with different microcrystalline silicon that give rise to shallow states in the silicon band gap. The excitons possess a rather delocalized wave function, couple to electron spins in conduction band tail states nearby, and take part in a spin-dependent recombination process. Our study shows that extended defects such as grain boundaries or stacking faults in the crystalline part of the material act as charge carrier traps that can influence the material conductivity.

  19. Evaluation of Drug Release From Coated Pellets Based on Isomalt, Sugar, and Microcrystalline Cellulose Inert Cores

    OpenAIRE

    2010-01-01

    The objective of the present study was to investigate the effect of the pellet core materials isomalt, sugar, and microcrystalline cellulose on the in vitro drug release kinetics of coated sustained-release pellets as well as to evaluate the influence of different ratios of polymethacrylate copolymers exhibiting different permeability characteristics on the drug release rate. For characterization of the drug release process of pellets, the effect of osmolality was studied using glucose as an ...

  20. Microcrystalline B-doped window layers prepared near amorphous to microcrystalline transition by HWCVD and its application in amorphous silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, P. [Department of Physics/Center of Optical Technologies and Laser Controlled Processes, University of Kaiserslautern, P.O. Box 3049, Kaiserslautern D-67653 (Germany)]. E-mail: kumarp@rhrk.uni-kl.de; Kupich, M. [Department of Physics/Center of Optical Technologies and Laser Controlled Processes, University of Kaiserslautern, P.O. Box 3049, Kaiserslautern D-67653 (Germany); Grunsky, D. [Department of Physics/Center of Optical Technologies and Laser Controlled Processes, University of Kaiserslautern, P.O. Box 3049, Kaiserslautern D-67653 (Germany); Schroeder, B. [Department of Physics/Center of Optical Technologies and Laser Controlled Processes, University of Kaiserslautern, P.O. Box 3049, Kaiserslautern D-67653 (Germany)

    2006-04-20

    The electronic and structural properties of p-type microcrystalline silicon films prepared near the microcrystalline to amorphous ({mu}c-amorphous) transition by hot-wire chemical vapor deposition are studied. Silane is used as a source gas while H{sub 2} as diluent and trimethylboron (TMB) and boron trifluoride (BF{sub 3}) as doping gases. Increasing TMB concentration from 0.01% to 5% favors the amorphous growth whereas for BF{sub 3} the crystalline fraction remains constant. The dark conductivity ({sigma} {sub d}) of {mu}c-Si:H p-layers remains approximately constant for TMB 1-5% at constant crystalline fraction X {sub c}. This dark conductivity behavior is attributed to the decrease in doping efficiency with increasing TMB concentration. The best initial efficiency obtained for a 400 nm amorphous pin solar cell with optimized {mu}c-Si:H p-layer is 7.7% (V {sub oc} = 874 mV, J {sub sc} = 12.91 mA/cm{sup 2}, FF = 68%)

  1. Advax™, a novel microcrystalline polysaccharide particle engineered from delta inulin, provides robust adjuvant potency together with tolerability and safety.

    Science.gov (United States)

    Petrovsky, Nikolai; Cooper, Peter D

    2015-11-04

    There is an ongoing need for new adjuvants to facilitate development of vaccines against HIV, tuberculosis, malaria and cancer, amongst many others. Unfortunately, the most potent adjuvants are often associated with toxicity and safety issues. Inulin, a plant-derived polysaccharide, has no immunological activity in its native soluble form but when crystallized into a stable microcrystalline particulate from (delta inulin) acquires potent adjuvant activity. Delta inulin has been shown to enhance humoral and cellular immune responses against a broad range of co-administered viral, bacterial, parasitic and toxin antigens. Inulin normally crystallizes as large heterogeneous particles with a broad size distribution and variable solubility temperatures. To ensure reproducible delta inulin particles with a consistent size distribution and temperature of solubility, a current Good Manufacturing Practice (cGMP) process was designed to produce Advax™ adjuvant. In its cCMP form, Advax™ adjuvant has proved successful in human trials of vaccines against seasonal and pandemic influenza, hepatitis B and insect sting anaphylaxis, enhancing antibody and T-cell responses while being safe and well tolerated. Advax™ adjuvant represents a novel human adjuvant that enhances both humoral and cellular immunity. This review describes the discovery and development of Advax™ adjuvant and research into its unique mechanism of action.

  2. FTIR spectroscopy and X-ray powder diffraction characterization of microcrystalline cellulose obtained from alfa fibers

    Directory of Open Access Journals (Sweden)

    Trache D.

    2013-07-01

    Full Text Available Many cereal straws have been used as raw materials for the preparation of microcrystalline cellulose (MCC. These raw materials were gradually replaced with wood products; nevertheless about 10% of the world overall pulp production is obtained from non-wood raw material. The main interest in pulp made from straw is that it provides excellent fibres for different industries with special properties, and that it is the major available source of fibrous raw material in some geographical areas. The aim of the present work was to characterize microcrystalline cellulose prepared from alfa fibers using the hydrolysis process. The products obtained are characterized with FTIR spectroscopy and X-ray powder diffraction. As a result, FTIR spectroscopy is an appropriate technique for studying changes occurred by any chemical treatment. The spectrum of alfa grass stems shows the presence of lignin and hemicelluloses. However, the cellulose spectrum indicates that the extraction of lignin and hemicellulose was effective. The X-ray analysis indicates that the microcrystalline cellulose is more crystalline than the source material.

  3. Influence of Water on the Structure and Dielectric Properties of the Microcrystalline and Nano-Cellulose

    Science.gov (United States)

    Kovalov, Kostiantyn M.; Alekseev, Olexander M.; Lazarenko, Maxim M.; Zabashta, Yu F.; Grabovskii, Yurii E.; Tkachov, Sergii Yu

    2017-07-01

    Influence of water in the different states on a structure and dielectric properties of microcrystalline cellulose were studied by of X-ray, thermogravimetry, and dielectric spectroscopy. At research of microcrystalline cellulose (MCC) with different content of water, it is shown that the molecules of water are located in the macropores of MCC and in multimolecular hydrated layers. It is shown that at the increase of concentration of water in a hydrated shell, the reorganization of molecules of cellulose in the surface of crystallites takes place, and as a result, their transversal size and crystallinity increase. It is shown that during the concentration of water, more than 13% in a continuous hydrated shell of crystallites appears. Temperature dependences of actual and imaginary parts of complex dielectric permittivity were studied in the interval of temperatures [-180 ÷ 120] °C on frequencies of f = 5, 10, 20, and 50 kHz. A low-temperature relaxation process and high-temperature transition were observed. Low-temperature relaxation process which is related to transition of surface methylol groups of molecules of cellulose conformation from tg to tt is shifted toward low temperatures at the increase of concentration of water in microcrystalline cellulose.

  4. Micromorph tandem solar cells: optimization of the microcrystalline silicon bottom cell in a single chamber system

    Institute of Scientific and Technical Information of China (English)

    Zhang Xiao-Dan; Zheng Xin-Xia; Xu Sheng-Zhi; Lin Quan; Wei Chang-Chun; Sun Jian; Geng Xin-Hua; Zhao Ying

    2011-01-01

    We report on the development of single chamber deposition of microcrystalline and micromorph tandem solar cells directly onto low-cost glass substrates.The cells have pin single-junction or pin/pin double-junction structures on glass substrates coated with a transparent conductive oxide layer such as SnO2 or ZnO.By controlling boron and phosphorus contaminations,a single-junction microcrystalline silicon cell with a conversion efficiency of 7.47% is achieved with an i-layer thickness of 1.2 μm.In tandem devices,by thickness optimization of the microcrystalline silicon bottom solar cell,we obtained an initial conversion efficiency of 9.91% with an aluminum (Al) back reflector without a dielectric layer.In order to enhance the performance of the tandem solar cells,an improved light trapping structure with a ZnO/Al back reflector is used.As a result,a tandem solar cell with 11.04% of initial conversion efficiency has been obtained.

  5. Plasma deposition of microcrystalline silicon solar cells. Looking beyond the glass

    Energy Technology Data Exchange (ETDEWEB)

    Donker, M.N. van den

    2006-07-01

    Microcrystalline silicon emerged in the past decade as highly interesting material for application in efficient and stable thin film silicon solar cells. It consists of nanometer-sized crystallites embedded in a micrometer-sized columnar structure, which gradually evolves during the SiH{sub 4} based deposition process starting from an amorphous incubation layer. Understanding of and control over this transient and multi-scale growth process is essential in the route towards low-cost microcrystalline silicon solar cells. This thesis presents an experimental study on the technologically relevant high rate (5-10 Aa s{sup -1}) parallel plate plasma deposition process of state-of-the-art microcrystalline silicon solar cells. The objective of the work was to explore and understand the physical limits of the plasma deposition process as well as to develop diagnostics suitable for process control in eventual solar cell production. Among the developed non-invasive process diagnostics were a pyrometer, an optical spectrometer, a mass spectrometer and a voltage probe. Complete thin film silicon solar cells and modules were deposited and characterized. (orig.)

  6. Microcrystalline diamonds in the oceanic lithosphere and their nature

    Science.gov (United States)

    Galimov, E. M.; Sevastyanov, V. S.; Karpov, G. A.; Shilobreeva, S. N.; Maksimov, A. P.

    2016-07-01

    The carbon isotope composition of microdiamonds found in products of the Tolbachik Volcano eruption, Kamchatka (porous lavas and ash), was studied. The isotope composition of microdiamonds (with an average value of δ13C =-25.05‰) is close to that of microsized carbon particles in lavas (from-28.9 to-25.3‰). The general peculiarities of the diamond-forming environment include (1) no evidence for high pressure in the medium; (2) a reduced environment; and (3) mineralogical evidence for the presence of a fluid. The geochemical data characterizing the type of diamonds studied allow us to suggest that they were formed in accordance with the mechanism of diamond synthesis during cavitation in a rapidly migrating fluid, which was suggested by E.M. Galimov.

  7. Bioavailability of ibuprofen from matrix mini-tablets based on a mixture of starch and microcrystalline wax.

    Science.gov (United States)

    De Brabander, C; Vervaet, C; Görtz, J P; Remon, J P; Berlo, J A

    2000-11-01

    The bioavailability of ibuprofen from matrix mini-tablets based on microcrystalline wax and a starch derivative was tested. An oral dose of 300 mg of ibuprofen was administered to healthy volunteers (n=8) in a randomized cross-over study design either as a commercial matrix formulation (Ibu-Slow 600) or as mini-tablets (filled into hard gelatin capsules). The mini-tablets consisted of 60% ibuprofen, 15% Paracera M (wax), 22.5% DDWM (starch) and 2.5% triacetin (lubricant). t50% of the in vitro release was 4.5 and 5 h for the mini-tablet and Ibu-slow formulations, respectively. Both formulations behaved in vivo as sustained-release formulation; their HVDt50%Cmax value was determined at 5.6 and 5.1 h for the mini-tablet and Ibu-slow formulations, respectively. A significantly higher value of Cmax was seen for the mini-tablet formulation, resulting in a relative bioavailability of 116 +/- 22.6% compared to the Ibu-slow matrix. These data demonstrate that the experimental mini-tablets can be used to formulate sustained-release dosage forms.

  8. Evaluation of Microcrystalline Chitosan and Fibrin Membranes as Platelet-Derived Growth Factor-BB Carriers with Amoxicillin

    Directory of Open Access Journals (Sweden)

    Kazimiera H. Bodek

    2015-01-01

    Full Text Available The aim of this study was to describe the mechanical and sorption features of homogeneous and composite membranes which consist of microcrystalline chitosan (MCCh and fibrin (Fb in various proportions as well as the in vitro kinetics of platelet-derived growth factor-BB (PDGF-BB released from ten types of membranes in the presence or absence of amoxicillin (Am. The films were characterized by Fourier transform infrared (FTIR spectroscopy, mechanical tests: breaking strength (Bs and elongation at break (Eb, as well as SEM images, and swelling study. The influence of the form of samples (dry or wet on Young’s modulus (E was also examined. The homogeneous MCCh (M1 and composite M3 and M4 (MCCh : Fb = 2 : 1 and 1 : 1 membranes were characterized by good sorption properties and higher mechanical strength, when compared with Fb (M2 membrane. Connecting MCCh with Fb decreases release of PDGF-BB and increases release of Am. The most efficient release of PDGF-BB was observed in the case of M4 (the optimum MCCh : Fb ratio was 1 : 1 membrane. It was found that the degree of PDGF-BB release from the membrane is influenced by the physicochemical and mechanical characteristics of the films and by its affinity to growth factor PDGF-BB.

  9. Growth and microstructure properties of microcrystalline silicon films deposited using jet-ICPCVD

    Institute of Scientific and Technical Information of China (English)

    Zuo Zewen; Guan Wentian; Xin Yu; Lü Jin; Wang Junzhuan; Pu Lin; Shi Yi; Zheng Youdou

    2011-01-01

    Microcrystalline silicon films were deposited at a high rate and low temperature using jet-type inductively coupled plasma chemical vapor deposition (jet-ICPCVD).An investigation into the deposition rate and microstructure properties of the deposited films showed that a high deposition rate of over 20 nm/s can be achieved while maintaining reasonable material quality.The deposition rate can be controlled by regulating the generation rate and transport of film growth precursors.The film with high crystallinity deposited at low temperature could principally result from hydrogen-induced chemical annealing.

  10. Composition of macro- and microcrystalline paraffin waxes; Ueber die Zusammensetzung von makro- und mikrokristallinen Paraffinen

    Energy Technology Data Exchange (ETDEWEB)

    Matthaei, M.; Butz, Th. [Schuemann Sasol GmbH, Hamburg (Germany); Geissler, A. [Hochschule Zittau/Goerlitz (Germany)

    2002-09-01

    This paper reviews investigations into the composition of macro- and micro-crystalline paraffin waxes, focussed on the structure of non n-alkanes. The review covers a wide spectrum of investigations from the last 50 years. Applied analytical methods and results of paraffin wax analysis are compiled. The knowledge about qualitative and quantitative composition of non n-alkanes in paraffin waxes is mainly based on older publications. These results are differing from each other since different products and different analytical methods have been used. The paper refers to ongoing investigations based on the current instrumental analytics. (orig.)

  11. Preparation of microcrystalline mixtures for calibration of laser microbeam ionisation mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Ignatova, V. E-mail: velislav@uia.ua.ac.be; Vaeck, L. van; Ham, R. van; Adriaens, A.; Adams, F

    2002-03-11

    In this paper we describe the optimized experimental procedure and the apparatus to prepare microcrystalline samples of inorganic salt mixtures to be used as molecular standards in Laser Microprobe Mass Spectrometry (LMMS). Experimental data show the suitability of the approach for preparation of solid mixtures of various inorganic salts. The structure and homogeneity of the samples are studied by Scanning Electron Microscopy and Fourier Transform LMMS. Specifically, the in-sample and between-sample reproducibility reveals that the method allows the local sample composition to be sufficiently homogeneous for subsequent use in the semi-quantitative calibration of the molecular signals in LMMS.

  12. Preparation of microcrystalline mixtures for calibration of laser microbeam ionisation mass spectrometry

    CERN Document Server

    Ignatova, V A; Ham, R V; Adriaens, A; Adams, F

    2002-01-01

    In this paper we describe the optimized experimental procedure and the apparatus to prepare microcrystalline samples of inorganic salt mixtures to be used as molecular standards in Laser Microprobe Mass Spectrometry (LMMS). Experimental data show the suitability of the approach for preparation of solid mixtures of various inorganic salts. The structure and homogeneity of the samples are studied by Scanning Electron Microscopy and Fourier Transform LMMS. Specifically, the in-sample and between-sample reproducibility reveals that the method allows the local sample composition to be sufficiently homogeneous for subsequent use in the semi-quantitative calibration of the molecular signals in LMMS.

  13. Densification-induced conductivity percolation in high-porosity pharmaceutical microcrystalline cellulose compacts

    Science.gov (United States)

    Strømme, M.; Niklasson, G. A.; Ek, R.

    2003-01-01

    The percolation theory is established as a useful tool in the field of pharmaceutical materials science. It is shown that percolation theory, developed for analyzing insulator-conductor transitions, can be applied to describe imperfect dc conduction in pharmaceutical microcrystalline cellulose during densification. The system, in fact, exactly reproduces the values of the percolation threshold and exponent estimated for a three-dimensional random continuum. Our data clearly show a crossover from a power-law percolation theory region to a linear effective medium theory region at a cellulose porosity of ˜0.7.

  14. Microcrystalline coatings deposited by series double-pole electro-pulse discharge and its high-temperature oxidation behavior

    Institute of Scientific and Technical Information of China (English)

    徐强; 何业东; 王德仁; 齐慧滨; 李正伟; 高唯

    2002-01-01

    A new technique--series electro-pulse discharge (SEPD)--was developed as a surface coating process. In this process, both positive and negative poles of a pulse power were used as the depositing electrodes and the substrate alloy was used as an induction electrode. The physical process for such SEPD was tested by measuring the relationship between the discharge voltages and gaps in a pin-plate-pin system. Microcrystalline Ni20Cr alloy coatings and oxide- dispersed Ni20Cr alloy coatings were prepared on Ni20Cr alloy surface by using a vibrating SEPD device. Oxidation at 950℃ in ambient air showed that the microcrystalline Ni20Cr alloy coatings greatly improved the oxidation resistance of the substrate alloy. The addition of dispersed Y2O3 nano-particles into the microcrystalline coatings was found to further reduce the oxidation rate and enhance the oxide spallation resistance.

  15. Color changing in denture base polyamide 12 and polyamide microcrystalline after polishing in laboratory and dental clinic

    Science.gov (United States)

    Sari, N. M. G. A. W.; Fardaniah, S.; Masulili, C.

    2017-08-01

    This study’s purpose was to compare color changes from polyamide 12 and polyamide microcrystalline materials. Each material was divided into two groups, polished with laboratory and clinical polishing equipment, and then immersed in a 28 °C coffee solution for seven days. Surface roughness was measured with a profilometer before the immersion. Color (L*, a*, and b*) was measured using a spectrophotometer before and after immersion. There were no significant color changes in the polyamide 12 and polyamide microcrystalline materials after immersion in the coffee solution.

  16. Crystallinity and thermal resistance of microcrystalline cellulose prepared from manau rattan (Calamusmanan)

    Science.gov (United States)

    Rizkiansyah, Raden Reza; Mardiyati, Steven, Suratman, R.

    2016-04-01

    The objective of this study was to prepare microcrystalline cellulose from Manau rattan (Calamusmanan) and to investigate the influence of concentration of sulfuric acid and hydrolysis time on crystallinity and thermal resistance of the microcrystalline cellulose (MCC). In this research, MCC was extracted through two stages, which is alkalization and acid hydrolysis. Alkalization was prepared by soaking manau rattan powder into sodium hydroxide (NaOH) 17.5wt% at 100°C for 8 hours. Acid hydrolysis was prepared by using sulfuric acid with concentration 0.1 M; 0.3 M; and 0.5 M for 4, 6, 8 and 10 hours. Crystallinity of MCC was measured by XRD, and thermal resistance was characterized by TGA. MCC was successfully extracted from manau rattan. The highest crystallinity of MCC obtained was 72.42% which prepared by acid hydrolysis with concentration 0.5 M for 10 hours. MCC prepared by acid hydrolysis with concentration 0.5 M for 10 hours not only resulted the highest crystallinity but also the best thermal resistance.

  17. Advantages of N-Type Hydrogenated Microcrystalline Silicon Oxide Films for Micromorph Silicon Solar Cells

    Directory of Open Access Journals (Sweden)

    Amornrat Limmanee

    2013-01-01

    Full Text Available We report on the development and application of n-type hydrogenated microcrystalline silicon oxide films (n μc-SiO:H in hydrogenated amorphous silicon oxide/hydrogenated microcrystalline silicon (a-SiO:H/μc-Si:H micromorph solar cells. The n μc-SiO:H films with high optical bandgap and low refractive index could be obtained when a ratio of carbon dioxide (CO2 to silane (SiH4 flow rate was raised; however, a trade-off against electrical property was observed. We applied the n μc-SiO:H films in the top a-SiO:H cell and investigated the changes in cell performance with respect to the electrical and optical properties of the films. It was found that all photovoltaic parameters of the micromorph silicon solar cells using the n top μc-SiO:H layer enhanced with increasing the CO2/SiH4 ratio up to 0.23, where the highest initial cell efficiency of 10.7% was achieved. The enhancement of the open circuit voltage (Voc was likely to be due to a reduction of reverse bias at subcell connection—n top/p bottom interface—and a better tunnel recombination junction contributed to the improvement in the fill factor (FF. Furthermore, the quantum efficiency (QE results also have demonstrated intermediate-reflector function of the n μc-SiO:H films.

  18. Preparation of hydrogenated microcrystalline silicon films with hot-wire-assisted MWECR-CVD system

    Institute of Scientific and Technical Information of China (English)

    He Bin; Chen Guang-Hua; Zhu Xiu-Hong; Zhang Wen-Li; Ding Yi; Ma Zhan-Jie; Gao Zhi-Hua; Song Xue-Mei; Deng Jin-Xiang

    2006-01-01

    Intrinsic hydrogenated microcrystalline silicon (μc-Si:H) films have been prepared by hot-wire-assisted microwave electron-cyclotron-resonance chemical vapour deposition (Hw-MwECR-CVD) under different deposition conditions.Fourier-transform infrared spectra and Raman spectra were measured.Optical band gap WaS determined by Tauc plots,and experiments of photo-induced degradation were performed.It was observed that hydrogen dilution plays a more essential role than substrate temperature in microcrystalline transformation at low temperatures. Crystalline volume fraction and mean grain size in the films increase with the dilution ratio (R=H2/(H2+SiH4)).With the rise of crystallinity in the films,the optical band gap tends to become narrower while the hydrogen content and photo-induced degradation decrease dramatically.The samples,were identified as μc-Si:H films,by calculating the optical band gap.It is considered that hydrogen dilution has an effect on reducing the crystallization activation energy of the material,which promotes the heterogeneous solid-state phase transition characterized by the Johnson-Mehl-Avrami (JMA) equation.The films with the needed structure can be prepared by balancing deposition and crystaUization through controlling process parameters.

  19. Preparation and Characterization of Cellulose Microcrystalline (MCC) from Fiber of Empty Fruit Bunch Palm Oil

    Science.gov (United States)

    Nasution, H.; Yurnaliza; Veronicha; Irmadani; Sitompul, S.

    2017-03-01

    Alpha cellulose which was isolated from cellulose of fiber empty fruit bunch palm oil was hidrolized with hydrochloric acid (2,5N) at 80°C to produce microcrystalline cellulose (MCC). Microcrystalline cellulose is an important additional ingredient in the pharmaceutical, food, cosmetics, and structural composites. In this study, MCC, alpha cellulose, and cellulose were characterized and thereafter were compared. Characterizations were made using some equipment such as x-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscopy (SEM) and thermogravimetry analyzer (TGA). X-ray diffraction and infrared spectroscopy were studied to determine crystallinity and molecular structure of MCC, where scanning electron microscopy images were conducted for information about morfology of MCC. Meanwhile, thermal resistance of MCC was determined using thermogravimetry analyzer (TGA). From XRD and FTIR, the obtained results showed that the crystalline part was traced on MCC, where the –OH and C-O groups tended to reduced as alpha cellulose has changed to MCC. From SEM the image showed the reduction of particle size of MCC, while the thermal resistance of MCC was found lower as compared with cellulose and alpha cellulose as well, which was attributed to the lower molecular weight of MCC.

  20. Fenton chemistry-based detemplation of an industrially relevant microcrystalline beta zeolite. Optimization and scaling-up studies

    NARCIS (Netherlands)

    Ortiz-Iniesta, Maria Jesus; Melian-Cabrera, Ignacio

    2015-01-01

    A mild template removal of microcrystalline beta zeolite, based on Fenton chemistry, was optimized. Fenton detemplation was studied in terms of applicability conditions window, reaction rate and scale up. TGA and CHN elemental analysis were used to evaluate the detemplation effectiveness, while 'CP,

  1. Facile synthesis of TiO2/microcrystalline cellulose nanocomposites: photocatalytically active material under visible light irradiation

    Science.gov (United States)

    Doped TiO2 nanocomposites were prepared in situ by a facile and simple synthesis utilizing benign and renewable precursors such as microcrystalline cellulose (MC) and TiCl4 through hydrolysis in alkaline medium without the addition of organic solvents. The as-prepared nanocompos...

  2. Determination of nickel by flame atomic-absorption spectrophotometry after separation by adsorption of its nioxime complex on microcrystalline naphthalene.

    Science.gov (United States)

    Nagahiro, T; Puri, B K; Katyal, M; Satake, M

    1984-11-01

    A method has been developed for the determination of nickel in alloys by flame atomic-absorption spectrophotometry after formation of a water-insoluble complex, its adsorption on microcrystalline naphthalene, and dissolution of the complex and naphthalene in nitric acid and xylene.

  3. Facile synthesis of TiO2/microcrystalline cellulose nanocomposites: photocatalytically active material under visible light irradiation

    Science.gov (United States)

    Doped TiO2 nanocomposites were prepared in situ by a facile and simple synthesis utilizing benign and renewable precursors such as microcrystalline cellulose (MC) and TiCl4 through hydrolysis in alkaline medium without the addition of organic solvents. The as-prepared nanocompos...

  4. Dissolution profile of novel composite pellet cores based on different ratios of microcrystalline cellulose and isomalt.

    Science.gov (United States)

    Luhn, Oliver; Kállai, Nikolett; Nagy, Zsombor Kristóf; Kovács, Kristóf; Fritzsching, Bodo; Klebovich, Imre; Antal, István

    2012-08-01

    There is a growing interest towards the application of inert cores as starting materials for pharmaceutical pellet manufacturing. They serve as alternatives to develop and adapt a relatively simple manufacturing technology compared with an extrusion/spheronisation process. The major objective of this study was to investigate the effect of the compositions of core materials on the drug release profile. Pure microcrystalline cellulose (MCC), isomalt and different types of novel composite MCC-isomalt cores were layered with model drug (sodium diclofenac) and were coated with acrylic polymer. The effect of the osmolality in the gastrointestinal tract was simulated using glucose as osmotically active agent during in vitro dissolution tests. The results demonstrated the dependence of drug dissolution profile on the ratio of MCC and isomalt in the core and the influence of osmotic properties of the dissolution medium. Isomalt used in the composite core was able to decrease the vulnerability of the dissolution kinetics to the changes in the osmotic environment.

  5. Physical stability of a microcrystalline beta-sitosterol suspension in oil

    DEFF Research Database (Denmark)

    von Bonsdorff-Nikander, Anna; Karjalainen, Milja; Rantanen, Jukka

    2003-01-01

    in the particle size. A previous work described how to produce a microcrystalline beta-sitosterol suspension. The present study deals with the stability of that suspension. Recrystallisation was carried out by two different methods; one based on rapid the other based on slow cooling, whereby six different......-ray diffraction. Suspensions can, in most cases, be stored for 16 weeks without any changes to the size and habit. The only evidence of crystal growth came from a suspension with a low sterol concentration at a temperature of +4 degrees C. This is due to the dissolution-diffusion process which is affected...... by temperature and viscosity. Suspensions containing higher amounts of sterol remained stable, if stored at +4 or -19 degrees C, for 16 weeks. The suspensions included both hemihydrous and monohydrous beta-sitosterol crystals. Suspensions containing less sterol showed greater amounts of monohydrated crystals...

  6. Combined effect of nitrogen doping and nanosteps on microcrystalline diamond films for improvement of field emission

    Energy Technology Data Exchange (ETDEWEB)

    Mengui, U.A., E-mail: ursulamengui@gmail.com [INPE – Instituto Nacional de Pesquisas Espaciais Laboratório Associado de Sensores e Materiais – LAS, Av. dos Astronautas 1758, CP 515, CEP 12.245-970, São José dos Campos, SP (Brazil); Campos, R.A.; Alves, K.A.; Antunes, E.F. [INPE – Instituto Nacional de Pesquisas Espaciais Laboratório Associado de Sensores e Materiais – LAS, Av. dos Astronautas 1758, CP 515, CEP 12.245-970, São José dos Campos, SP (Brazil); Hamanaka, M.H.M.O. [Centro de Tecnologia da Informação Renato Archer, Divisão de Superfícies de Interação e Displays, Rodovia D. Pedro I (SP 65) km 143.6, CP 6162, CEP 13089-500, Campinas, SP (Brazil); Corat, E.J.; Baldan, M.R. [INPE – Instituto Nacional de Pesquisas Espaciais Laboratório Associado de Sensores e Materiais – LAS, Av. dos Astronautas 1758, CP 515, CEP 12.245-970, São José dos Campos, SP (Brazil)

    2015-04-15

    Highlights: • Hot filament chemical vapor deposition using methane, hydrogen and a solution of urea in methanol produced nitrogen-doped diamond films. • Diamonds had the grain morphology changed for long growth time (28 h), and the nitrogen doping were evaluated by Raman spectroscopy. • Field emission characterization shows a decrease up to 70% in threshold field, related to reference diamond layer. - Abstract: Nitrogen-doped microcrystalline diamond (N-MCD) films were grown on Si substrates using a hot filament reactor with methanol solution of urea as N source. Electrostatic self-assembly seeding of nanocrystalline diamond were used to obtain continuous and uniform films. Simultaneous changes in grains morphology and work function of diamond by nitrogen doping decreased the threshold field and the angular coefficient of Fowler–Nordhein plots. The field emission properties of our N-MCD films are comparable to carbon nanotube films.

  7. STRUCTURAL PROPERTIES INVESTIGATION ON MICROCRYSTALLINE SILICON FILMS DEPOSITED WITH VHF-PECVD TECHNIQUE

    Institute of Scientific and Technical Information of China (English)

    H.D. Yang

    2005-01-01

    Raman scattering spectroscopy and scanning electron microscopy (SEM) techniques were used to determine the structural properties of two typical series of microcrystalline silicon(μc-Si:H) films deposited at different VHF plasma power and different working gas pressure by very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD) technique. Raman spectra measurements show that both crystalline volume fraction Xc and average grain size d of μc-Si: H films are strongly affected by the two deposition conditions and are more sensitive to working gas pressure than VHF plasma power. SEM characterizations have further confirmed that VHF plasma power and working gas pressure could clearly enhance the surface roughness of μc-Si: H films ascribing to polymerization reactions, which is also more sensitive to working gas pressure than VHF plasma power.

  8. Isolation and Characterization of Microcrystalline Cellulose (MCC from Rice Husk (RH

    Directory of Open Access Journals (Sweden)

    Ahmad Zuliahani

    2016-01-01

    Full Text Available Microcrystalline cellulose (MCC was extracted from local agricultural residues, rice husk (RH. RH undergone alkaline, bleaching and acid hydrolysis treatments. Nitric acid was used in the hydrolysis process as a potential acid to replace strong acids such as hydrochloric and sulphuric acids. Hydrolysis of RH was carried out by using different molarity of nitric and hydrochloric acids (control. The properties of MCC obtained such as % yield, crystallinity index (CrI and functional group present were studied. % yield shown a comparable result regardless of different acid used. Whilst Fourier transform infrared (FTIR spectroscopy showed the progressive removal of non-cellulosic constituents. X-ray diffraction (XRD analysis revealed that the crystallinity increased with successive treatments regardless different molarity and acids used. The results showed potential of nitric acid to be used in MCC isolation process.

  9. Microcrystalline cellulose: Isolation, characterization and bio-composites application-A review.

    Science.gov (United States)

    Trache, Djalal; Hussin, M Hazwan; Hui Chuin, Caryn Tan; Sabar, Sumiyyah; Fazita, M R Nurul; Taiwo, Owolabi F A; Hassan, T M; Haafiz, M K Mohamad

    2016-12-01

    Considering its widespread usage in various fields, such as food, pharmaceutical, medical, cosmetic and polymer composites industries, microcrystalline cellulose (MCC) is becoming impellent due to increasing demand of alternatives to non-renewable and scarce fossil materials. Although it still suffers from some drawbacks, MCC has recently gained more interest owing to its renewability, non-toxicity, economic value, biodegradability, high mechanical properties, high surface area and biocompatibility. New sources, new isolation processes, and new treatments are currently under development to satisfy the increasing demand of producing new types of MCC-based materials on an industrial scale. Therefore, this review assembles the current knowledge on the isolation of MCC from different sources using various procedures, its characterization, and its application in bio-composites. Challenges and future opportunities of MCC-based composites are discussed as well as obstacles remaining for their extensive uses.

  10. Intermittent Very High Frequency Plasma Deposition on Microcrystalline Silicon Solar Cells Enabling High Conversion Efficiency

    Directory of Open Access Journals (Sweden)

    Mitsuoki Hishida

    2016-01-01

    Full Text Available Stopping the plasma-enhanced chemical vapor deposition (PECVD once and maintaining the film in a vacuum for 30 s were performed. This was done several times during the formation of a film of i-layer microcrystalline silicon (μc-Si:H used in thin-film silicon tandem solar cells. This process aimed to reduce defect regions which occur due to collision with neighboring grains as the film becomes thicker. As a result, high crystallinity (Xc of μc-Si:H was obtained. Eventually, a solar cell using this process improved the conversion efficiency by 1.3% (0.14 points, compared with a normal-condition cell. In this paper, we propose an easy method to improve the conversion efficiency with PECVD.

  11. Application of scanning Kelvin probe microscopy for the electrical characterization of microcrystalline silicon for photovoltaics

    CERN Document Server

    Breymesser, A

    2000-01-01

    constructed and built. Great effort was concentrated on the characterization of the SKPM experiment. On the basis of an extended knowledge about the performance investigations concentrated on cross sections of microcrystalline silicon diode structures produced by hot-wire chemical vapor deposition (HW-CVD). A pin structure for the diodes was chosen due to the low diffusion lengths within this rather defective material. The evolution of the built-in electric drift field within the intrinsic absorber is a prerequisite for obtaining high short circuit current densities. SKPM was able to provide information about the potential and electric field distribution within the cross-sectioned diode structures. In conjunction with simulations statements about actual defect and dopant distributions could be derived. Several diode structures with different deposition and compensation conditions of the naturally n-type intrinsic layer were investigated. In order to explore the character of the defects deep level transient sp...

  12. Preconcentrafion/separation and determination of mercury using microcrystalline phenolphthalein modified by ethyl violet

    Institute of Scientific and Technical Information of China (English)

    LI Ying; LI Quanrnin; OUYANG Ruizhuo

    2007-01-01

    A novel method was developed for enrichment and separation of trace mercury using phenolphthalein modified by ethyl violet (EV).The effects of different parameters,such as stirring time, various metal ions and salts,and the amounts of phenolphthalein, NH4SCN,and EV on the extraction rate of mercury were studied,to select the experimental conditions.Under optimum conditions,mercury can be adsorbed on the surface of microcrystalline phenolphthalein by the intermolecular action strength.The possible reaction mechanism for the enrichment of mercury was discussed in detail.Hg(Ⅱ)could be completely separated from Fe(Ⅱ),Co(Ⅱ),Ni(Ⅱ),Mn(Ⅱ),Cd(Ⅱ),Cr(Ⅲ), and Al(Ⅲ) in the solution.The proposed method has been successfully applied to the determination of trace mercury in industrial wastewater with the recoveries 1.4%,1.1%,and1.2%,respectively.The analytical results were very satisfactory.

  13. Fabrication of c-Si:H(p)/c-Si(n) Heterojunction Solar Cells with Microcrystalline Emitters

    Institute of Scientific and Technical Information of China (English)

    ZHOU Bing-Qing; LIU Feng-Zhen; ZHANG Qun-Fang; XU Ying; ZHOU Yu-Qin; LIU Jin-Long; ZHU Mei-Fang

    2006-01-01

    The p-type microcrystalline silicon (fj,c-Si) on n-type crystalline silicon (c-Si) heterojunction solar cells is fabricated by radio-frequency plasma enhanced chemical vapour deposition (rf-PECVD). The effect of the pc-Si:H p-layers on the performance of the heterojunction solar cells is investigated. Optimum μcSi:H p-layer is obtained with hydrogen dilution ratio of 99.65%, rf-power of 0.08 W/cm2, gas phase doping ratio of 0.125%, and the p-layer thickness of 15 nm. We fabricate μc-Si:H(p)/c-Si(n) heterojunction solar cells without texturing and obtained an efficiency of 13.4%. The comparisons of the solar-cell performances using different surface passivation techniques are discussed.

  14. Influence of total gas flow rate on microcrystalline silicon films prepared by VHF-PECVD

    Institute of Scientific and Technical Information of China (English)

    Gao Yan-Tao; Zhang Xiao-Dan; Zhao Ying; Sun Jian; Zhu Feng; Wei Chang-Chun; Chen Fei

    2006-01-01

    Hydrogenated microcrystalline silicon (μc-Si:H) films are fabricated by very high frequency plasma enhanced chemical vapour deposition (VHF-PECVD) at a silane concentration of 7% and a varying total gas flow rate (H2+SiH4).Relations between the total gas flow rate and the electrical and structural properties as well as deposition rate of the films are studied. The results indicate that with the total gas flow rate increasing the photosensitivity and deposition rate increase, but the crystalline volume fraction (Xc) and dark conductivity decrease. And the intensity of (220) peak first increases then decreases with the increase of the total gas flow rate. The cause for the changes in the structure and deposition rate of the films with the total gas flow rate is investigated using optical emission spectroscopy (OES).

  15. Absorption coefficient modeling of microcrystalline silicon thin film using Maxwell-Garnett effective medium theory.

    Science.gov (United States)

    Chen, Sheng-Hui; Wang, Hsuan-Wen; Chang, Ting-Wei

    2012-03-12

    Considering the Mott-Davis density of state model and Rayleigh scattering effect, we present an approach to model the absorption profile of microcrystalline silicon thin films in this paper. Maxwell-Garnett effective medium theory was applied to analyze the absorption curves. To validate the model, several experimental profiles have been established and compared with those results from the model. With the assistance of the genetic algorithm, our results show that the absorption curves from the model are in good agreement with the experiments. Our findings also indicate that, as the crystal volume fraction increases, not only do the defects in amorphous silicon reduce, but the bulk scattering effect is gradually enhanced as well.

  16. 大豆皮胶态微晶纤维素的流变学性质研究%Study on the rheological properties of microcrystalline cellulose from soybean hulls

    Institute of Scientific and Technical Information of China (English)

    李爱军; 张丽君; 胡丽娜; 欧仕益

    2012-01-01

    研究了浓度、剪切速率、剪切时间、静置时间、温度、金属离子等对大豆皮胶态微晶纤维素溶液粘度的影响。结果表明:大豆皮胶态MCC在水中可形成凝胶,低浓度的凝胶(小于2%)具有触变性;大豆皮胶态MCC溶液具有典型的剪切稀变性、良好的时变性和热稳定性;二价金属离子会使大豆皮胶态MCC溶液的粘度显著下降,当其浓度达到0.15mol/L或以上时,其假塑性会降低。%Effects of thickness, shearing rate,temperature, metal ion, shearing and stewing time on the rheological characteristics of microcrystalline cellulose from soybean hull were studied in this paper. Results showed that colloidal microcrystalline cellulose from soybean hulls formed gel in water and the low concentration solution( less than 2%)had the character of thixtropy. The solutions of colloidal soybean hulls microcrystalline cellulose had pseudoplastic behaviour and good thermal stability. Bivalent metal ions made the viscosity of the solutions decrease a lot and when the concentrations of bivalent metal ions rose to O.lSmol/L or more,the pseudoplastic behavior of the solution reduced.

  17. Friction and Wear Performance of Boron Doped, Undoped Microcrystalline and Fine Grained Composite Diamond Films

    Institute of Scientific and Technical Information of China (English)

    WANG Xinchang; WANG Liang; SHEN Bin; SUN Fanghong

    2015-01-01

    Chemical vapor deposition (CVD) diamond films have attracted more attentions due to their excellent mechanical properties. Whereas as-fabricated traditional diamond films in the previous studies don’t have enough adhesion or surface smoothness, which seriously impact their friction and wear performance, and thus limit their applications under extremely harsh conditions. A boron doped, undoped microcrystalline and fine grained composite diamond (BD-UM-FGCD) film is fabricated by a three-step method adopting hot filament CVD (HFCVD) method in the present study, presenting outstanding comprehensive performance, including the good adhesion between the substrate and the underlying boron doped diamond (BDD) layer, the extremely high hardness of the middle undoped microcrystalline diamond (UMCD) layer, as well as the low surface roughness and favorable polished convenience of the surface fine grained diamond (FGD) layer. The friction and wear behavior of this composite film sliding against low-carbon steel and silicon nitride balls are studied on a ball-on-plate rotational friction tester. Besides, its wear rate is further evaluated under a severer condition using an inner-hole polishing apparatus, with low-carbon steel wire as the counterpart. The test results show that the BD-UM-FGCD film performs very small friction coefficient and great friction behavior owing to its high surface smoothness, and meanwhile it also has excellent wear resistance because of the relatively high hardness of the surface FGD film and the extremely high hardness of the middle UMCD film. Moreover, under the industrial conditions for producing low-carbon steel wires, this composite film can sufficiently prolong the working lifetime of the drawing dies and improve their application effects. This research develops a novel composite diamond films owning great comprehensive properties, which have great potentials as protecting coatings on working surfaces of the wear-resistant and anti

  18. Nano- and microcrystalline diamond deposition on pretreated WC-Co substrates: structural properties and adhesion

    Science.gov (United States)

    Fraga, M. A.; Contin, A.; Rodríguez, L. A. A.; Vieira, J.; Campos, R. A.; Corat, E. J.; Trava Airoldi, V. J.

    2016-02-01

    Many developments have been made to improve the quality and adherence of CVD diamond films onto WC-Co hard metal tools by the removing the cobalt from the substrate surface through substrate pretreatments. Here we compare the efficiency of three chemical pretreatments of WC-Co substrates for this purpose. First, the work was focused on a detailed study of the composition and structure of as-polished and pretreated substrate surfaces to characterize the effects of the substrate preparation. Considering this objective, a set of WC-9% Co substrates, before and after pretreatment, was analyzed by FEG-SEM, EDS and x-ray diffraction (XRD). The second stage of the work was devoted to the evaluation of the influence of seeding process, using 4 nm diamond nanoparticles, on the morphology and roughness of the pretreated substrates. The last and most important stage was to deposit diamond coatings with different crystallite sizes (nano and micro) by hot-filament CVD to understand fully the mechanism of growth and adhesion of CVD diamond films on pretreated WC-Co substrates. The transition from nano to microcrystalline diamond was achieved by controlling the CH4/H2 gas ratio. The nano and microcrystalline samples were grown under same time at different substrate temperatures 600 °C and 800 °C, respectively. The different substrate temperatures allowed the analysis of the cobalt diffusion from the bulk to the substrate surface during CVD film growth. Furthermore, it was possible to evaluate how the coating adhesion is affected by the diffusion. The diamond coatings were characterized by Raman spectroscopy, XRD, EDS, FEG-SEM, atomic force microscope and 1500 N Rockwell indentation to evaluate the adhesion.

  19. Friction and wear performance of boron doped, undoped microcrystalline and fine grained composite diamond films

    Science.gov (United States)

    Wang, Xinchang; Wang, Liang; Shen, Bin; Sun, Fanghong

    2015-01-01

    Chemical vapor deposition (CVD) diamond films have attracted more attentions due to their excellent mechanical properties. Whereas as-fabricated traditional diamond films in the previous studies don't have enough adhesion or surface smoothness, which seriously impact their friction and wear performance, and thus limit their applications under extremely harsh conditions. A boron doped, undoped microcrystalline and fine grained composite diamond (BD-UM-FGCD) film is fabricated by a three-step method adopting hot filament CVD (HFCVD) method in the present study, presenting outstanding comprehensive performance, including the good adhesion between the substrate and the underlying boron doped diamond (BDD) layer, the extremely high hardness of the middle undoped microcrystalline diamond (UMCD) layer, as well as the low surface roughness and favorable polished convenience of the surface fine grained diamond (FGD) layer. The friction and wear behavior of this composite film sliding against low-carbon steel and silicon nitride balls are studied on a ball-on-plate rotational friction tester. Besides, its wear rate is further evaluated under a severer condition using an inner-hole polishing apparatus, with low-carbon steel wire as the counterpart. The test results show that the BD-UM-FGCD film performs very small friction coefficient and great friction behavior owing to its high surface smoothness, and meanwhile it also has excellent wear resistance because of the relatively high hardness of the surface FGD film and the extremely high hardness of the middle UMCD film. Moreover, under the industrial conditions for producing low-carbon steel wires, this composite film can sufficiently prolong the working lifetime of the drawing dies and improve their application effects. This research develops a novel composite diamond films owning great comprehensive properties, which have great potentials as protecting coatings on working surfaces of the wear-resistant and anti

  20. Amorphous and microcrystalline silicon applied in very thin tandem solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Schicho, Sandra

    2011-07-28

    Thin-film solar cells are fabricated by low-cost production processes, and are therefore an alternative to conventionally used wafer solar cells based on crystalline silicon. Due to the different band gaps, tandem cells that consist of amorphous (a-Si:H) and microcrystalline ({mu}c-Si:H) single junction solar cells deposited on top of each other use the solar spectrum much more efficient than single junction solar cells. The silicon layers are usually deposited on TCO (Transparent Conductive Oxide)-coated glass and metal- or plastic foils. Compared to the CdTe and CIGS based thin-film technologies, silicon thin-film solar cells have the advantage that no limitation of raw material supply is expected and no toxic elements are used. Nevertheless, the production cost per Wattpeak is the decisive factor concerning competitiveness and can be reduced by, e.g., shorter deposition times or reduced material consumption. Both cost-reducing conceptions are simultaneously achieved by reducing the a-Si:H and {mu}c-Si:H absorber layer thicknesses in a tandem device. In the work on hand, the influence of an absorber layer thickness reduction up to 77% on the photovoltaic parameters of a-Si:H/{mu}c-Si:H tandem solar cells was investigated. An industry-oriented Radio Frequency Plasma-Enhanced Chemical Vapour Deposition (RF-PECVD) system was used to deposit the solar cells on glass substrates coated with randomly structured TCO layers. The thicknesses of top and bottom cell absorber layers were varied by adjusting the deposition time. Reduced layer thicknesses lead to lower absorption and, hence, to reduced short-circuit current densities which, however, are partially balanced by higher open-circuit voltages and fill factors. Furthermore, by using very thin amorphous top cells, the light-induced degradation decreases tremendously. Accordingly, a thickness reduction of 75% led to an efficiency loss of only 21 %. By adjusting the parameters for the deposition of a-Si:H top cells, a

  1. The influence of the moisture content of microcrystalline cellulose on the coating process in a fluidized bed

    Directory of Open Access Journals (Sweden)

    Silva O. S.

    2004-01-01

    Full Text Available The objective of this work was to study the coating of microcrystalline cellulose with a polymeric suspension in a fluidized bed. The coating operation was carried out using a fluidized bed with top spraying by a double-fluid nozzle. The fluidized bed consists of a cylindrical column made of plexiglass with a height of 0.6 m and an inner diameter of 0.14 m. The polymeric coating suspension was formulated using Eudragit® as the basic component. As the quality of the coating product is greatly affected by the spraying characteristics, the influence of the flow rate of the coating suspension and the moisture content of the particles on the agglomeration index and efficiency of the process of coating microcrystalline cellulose was analyzed.

  2. Microcrystalline silicon from very high frequency plasma deposition and hot-wire CVD for ``micromorph`` tandem solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Brummack, H.; Brueggemann, R.; Wanka, H.N.; Hierzenberger, A.; Schubert, M.B. [Univ. Stuttgart (Germany). Inst. fuer Physikalische Elektronik

    1997-12-31

    The authors have grown microcrystalline silicon from a glow discharge at very high frequencies of 55 MHz and 170 MHz with high hydrogen dilution, and also, at more than 10 times higher growth rates, similar films by hot-wire chemical vapor deposition. Both kinds of materials have extensively been characterized and compared in terms of structural, optical and electronic properties, which greatly improve by deposition in a multi- instead of a single-chamber system. Incorporation of these different materials into pin solar cells results in open circuit voltages of about 400 mV as long as the doped layers are microcrystalline and rise to more than 870 mV if amorphous p- and n-layers are used. Quantum efficiencies and fill factors are still poor but leave room for further improvement, as clearly demonstrated by a remarkable reverse bias quantum efficiency gain.

  3. Use of the microcrystalline limestone as building material: the "GrisPulpis"case

    Directory of Open Access Journals (Sweden)

    García del Cura, M. A.

    2005-03-01

    Full Text Available Gris Pulpis is a Jurassic microcrystalline limestone found in the Maestrazgo Area of the Iberian Mountain Range (province of Castellón, Spain. This paper reports the results of a detailed study of the mineralogical, pelrographic and chromatic characteristics, as well as the durability, of this stone, classified as a commercial marble for its polish ability. The study determined the relationship between the structural characteristics of the stone, with a proliferation of stylolites and veins, and its physical properties. Its flexura I strength was found to be greater than would normally be expected in a structure with such a dense web of stylolites and veins. This is due to the structural and mineralogical properties of these stylolites, characterised by an extremely wavy design, scant mineral infillings and, occasionally, subsequent cementation. The characteristics of the porous media of homogeneous microcrystalline limestones such as Gris Pulpis largely explain the durability of this stone when exposed to freeze-thaw cycles and salt crystallisation. These arc the properties that make Gris Pulpis limestone, quarried in the Spanish Region of Valencia, a valuable building material for both architectural and civil engineering applications

    En este trabajo se analizan las propiedades físicas y la durabilidad de una caliza microcristalina.El Gris Pulpis es una caliza microcristalina del Jurásico de la Cordillera Ibérica (Maestrazgo, cuyas características mineralógicas, petrográficas, cromáticas y alterabilidad se determinan detalladamente. Su aptitud para el pulido hace que sea un mármol comercial. Se establece la influencia de sus características estructurales (estilolitos, vénulas... en sus propiedades físicas. Su resistencia a flexión supera los valores que cabría esperar en función de la estructura de esta roca que, a veces, presenta abundantes estilolitos y vénulas. Esto es debido a las características estructurales y

  4. Influence of Tableting on Enzymatic Activity of Papain along with Determination of Its Percolation Threshold with Microcrystalline Cellulose.

    Science.gov (United States)

    Sharma, Manu; Sharma, Vinay; Majumdar, Dipak K

    2014-01-01

    The binary mixture tablets of papain and microcrystalline cellulose (MCC), dicalcium phosphate dihydrate (DCP), carrageenan, tragacanth, and agar were prepared by direct compression. Carrageenan, tragacanth, and agar provided maximum protection to enzyme activity compared to MCC and DCP. However, stability studies indicated highest loss of enzyme activity with carrageenan, tragacanth, and agar. Therefore, compression behaviour of different binary mixtures of papain with MCC at different compaction pressures, that is, 40-280 MPa, was studied according to Heckel equation. The compressibility studies of binary mixtures indicated brittle behavior of papain. The application of percolation theory on the relationship between critical density as a function of enzyme activity and mixture composition revealed the presence of percolation threshold for binary mixture. Papain-MCC mixture composition showed significant percolation threshold at 18.48% (w/w) papain loading. Microcrystalline cellulose provided higher protection during stability study. However, higher concentrations of microcrystalline cellulose, probably as dominant particles, do not protect the enzyme with their plastic deformation. Below the percolation threshold, that is, 18.48% (w/w) papain amount in mixture with plastic excipient, activity loss increases strongly because of higher shearing forces during compaction due to system dominance of plastic particles. This mixture range should therefore be avoided to get robust formulation of papain.

  5. Extraction of microcrystalline cellulose from rice straw and its effect on polyvinyl alcohol biocomposites film

    Science.gov (United States)

    Chin, Kwok-Mern; Ting, Sam Sung; Lin, Ong Hui; Owi, Wei Tieng

    2017-07-01

    The poor management and underutilization of agricultural wastes had proliferated interest of researchers around the world to find alternatives to utilize them as potential value-added products. One of the green alternatives is by extracting cellulose from these waste materials and incorporating them in polymer as reinforcement fillers. The surging amount of plastic waste also posed major issues to the environment due to its recalcitrance to degrade. Microcrystalline cellulose (MCC-RS) was extracted from rice straw through cyclic alkaline and bleaching treatment to remove hemicellulose and lignin respectively. Polyvinyl alcohol (PVOH) was chosen as the matrix and different ratios of PVOH / MCC-RS films were prepared (2.5, 5.0, 7.5 and 10.0wt% of MCC) through solution casting method and its tensile, thermal and morphological properties were studied. X-ray powder diffraction (XRD) results showed increased crystallinity of MCC-RS after chemical treatment (from 44.5% to 60.8%) due to the successful removal of lignin and hemicellulose, which was then confirmed with Fourier transform infrared spectroscopy (FTIR) results. For the biocomposites, both tensile strength and Young's modulus of the films increased with increasing MCC-RS content up until 7.5wt%, supported with scanning electron microscopy (SEM) results which depicted improvement in the interfacial adhesion between MCC-RS and PVOH. From the overall results, the improvement in properties of biocomposite from cellulose-based microfiller had shown promising future in application of the water soluble plastic packaging industry.

  6. Green synthesis of hybrid graphene oxide/microcrystalline cellulose aerogels and their use as superabsorbents

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Xiao; Huang, Ting; Yang, Jing-hui; Zhang, Nan; Wang, Yong, E-mail: yongwang1976@163.com; Zhou, Zuo-wan

    2017-08-05

    Highlights: • Hybrid GO/MCC aerogels were prepared using LiBr aqueous solution as the solvent. • GO was exfoliated by MCC through the strong interaction between them. • The adsorption ability of GO per unit mass in the hybrid aerogels was greatly enhanced. - Abstract: In this work, we developed a green synthesis method to prepare the hybrid aerogels containing graphene oxide (GO) and microcrystalline cellulose (MCC) using lithium bromide (LiBr) aqueous solution as the solvent, which insured the complete dissolution of MCC. The interaction between GO and MCC was investigated through different methods The results demonstrate that there is a strong interaction between GO and MCC molecules, which promotes the exfoliation of GO in the hybrid aerogels. The hybrid GO/MCC aerogels exhibit typical three dimensional porous structure and the pore morphology can be well adjusted by changing the content of GO. The adsorption ability of the hybrid aerogels was measured using methylene blue (MB) as an adsorbate. The results show that the adsorption ability of GO per unit mass is greatly enhanced compared with the pure GO aerogel, especially at relatively low GO content the adsorption amount of GO per unit mass is enhanced up to 2630 mg/g. Further results demonstrate that the hybrid GO/MCC aerogels still obey the pseudo-second-order adsorption model, which is similar to that of the pure GO aerogel. The mechanism for the amplified adsorption ability of GO in the hybrid GO/MCC aerogels is then analyzed.

  7. Evaluation of drug release from coated pellets based on isomalt, sugar, and microcrystalline cellulose inert cores.

    Science.gov (United States)

    Kállai, Nikolett; Luhn, Oliver; Dredán, Judit; Kovács, Kristóf; Lengyel, Miléna; Antal, István

    2010-03-01

    The objective of the present study was to investigate the effect of the pellet core materials isomalt, sugar, and microcrystalline cellulose on the in vitro drug release kinetics of coated sustained-release pellets as well as to evaluate the influence of different ratios of polymethacrylate copolymers exhibiting different permeability characteristics on the drug release rate. For characterization of the drug release process of pellets, the effect of osmolality was studied using glucose as an osmotically active agent in the dissolution medium. The pellet cores were layered with diclofenac sodium as model drug and coated with different ratios of Eudragit RS30D and Eudragit RL30D (ERS and ERL; 0:1 and 0.5:0.5 and 1:0 ratio) in a fluid bed apparatus. Physical characteristics such as mechanical strength, shape, and size proved that the inert cores were adequate for further processing. The in vitro dissolution tests were performed using a USP Apparatus I (basket method). The results demonstrated that, besides the ratio of the coating polymers (ERS/ERL), the release mechanism was also influenced by the type of starter core used. Sugar- and isomalt-type pellet cores demonstrated similar drug release profiles.

  8. Microstructure and mechanical properties of Ni and Fe-base boride-dispersion-strengthened microcrystalline alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wade, C.S.; Park, H.G.; Hoagland, R.G. (Ohio State Univ., Columbus (USA))

    This paper considers the relation between microstructure and mechanical properties of two Ni-base and two Fe-base Boride-Dispersion-Strengthened Microcrystalline (BDSM) alloys. In these very fine grained materials the borides were primarily Cr, Mo, and MoFe in a fcc matrix in three of the alloys, and a bcc in one of the Fe-base alloys. Strength data and resistance to stress corrosion cracking are reported and, in the latter case, extraordinary resistance to SCC in NaCl, Na{sub 2}S{sub 2}O{sub 3} and boiling MgCl{sub 2} environments was observed in every case. The fcc BDSM alloys also demonstrated excellent thermal stability in terms of strength and fracture roughness up to 1000 C. The bcc alloy suffered severe loss of toughness. The fracture mode involved ductile rupture in all alloys and they display a reasonably linear correlation between K{sub Ic} and the square root of particle spacing.

  9. Hydrolysis of microcrystalline cellulose using functionalized Bronsted acidic ionic liquids - A comparative study.

    Science.gov (United States)

    Parveen, Firdaus; Patra, Tanmoy; Upadhyayula, Sreedevi

    2016-01-01

    Cellulose conversion to platform chemicals is required to meet the demands of increasing population and modernization of the world. Hydrolysis of microcrystalline cellulose was studied with SO3H, COOH and OH functionalized imidazole based ionic liquid using 1-butyl-3-methylimidazolium chloride [BMIM]Cl as a solvent. The influence of temperature, time, acidity of ionic liquids and catalyst loading was studied on hydrolysis reaction. The maximum %TRS yield 85%, was obtained at 100°C and 90min with 0.2g of SO3H functionalized ionic liquid. UV-vis spectroscopy using 4-nitro aniline as an indicator was performed to find out the Hammett function of ionic liquid and acidity trends are as follows: SO3H>COOH>OH. Density functional theory (DFT) calculations were performed to optimize the ionic liquid and their conjugate bases at B3LYP 6-311G++ (d, p) level using Gaussian 09 program. Theoretical findings are in agreement with the experimental results. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. The Effect of Various Acids on Properties of Microcrystalline Cellulose (MCC) Extracted from Rice Husk (RH)

    Science.gov (United States)

    Nur Hanani, A. S.; Zuliahani, A.; Nawawi, W. I.; Razif, N.; Rozyanty, A. R.

    2017-05-01

    Microcrystalline cellulose (MCC) was successfully extracted from rice husk (RH) via acid hydrolysis process using nitric acid (HNO3) in comparison with sulphuric acid (H2SO4) and hydrochloric acid (HCl). MCC-RH extracted using HNO3 produced the highest percentage yield at 83.5% as compared to H2SO4 and HCl at 80.6% and 81.8% respectively. Analysis of Fourier Transform Infrared (FTIR) spectroscopy affirmed the successive elimination of non-cellulosic material from RH cellulose resulting highly purified MCC-RH. X-ray Diffraction (XRD) analysis showed MCC-RH treated with HCl gives the highest crystallinity index value of 54.2% while HNO3 and H2SO4 produced comparable results of 52.4% and 49.7% respectively. The results indicate successive extraction of MCC-RH using HNO3 that has great potential to replace strong acid such as H2SO4 and HCl in acid hydrolysis.

  11. Applicability of low-melting-point microcrystalline wax to develop temperature-sensitive formulations.

    Science.gov (United States)

    Matsumoto, Kohei; Kimura, Shin-Ichiro; Iwao, Yasunori; Itai, Shigeru

    2017-10-30

    Low-melting-point substances are widely used to develop temperature-sensitive formulations. In this study, we focused on microcrystalline wax (MCW) as a low-melting-point substance. We evaluated the drug release behavior of wax matrix (WM) particles using various MCW under various temperature conditions. WM particles containing acetaminophen were prepared using a spray congealing technique. In the dissolution test at 37°C, WM particles containing low-melting-point MCWs whose melting was starting at approx. 40°C (Hi-Mic-1045 or 1070) released the drug initially followed by the release of only a small amount. On the other hand, in the dissolution test at 20 and 25°C for WM particles containing Hi-Mic-1045 and at 20, 25, and 30°C for that containing Hi-Mic-1070, both WM particles showed faster drug release than at 37°C. The characteristic drug release suppression of WM particles containing low-melting-point MCWs at 37°C was thought attributable to MCW melting, as evidenced by differential scanning calorimetry analysis and powder X-ray diffraction analysis. Taken together, low-melting-point MCWs may be applicable to develop implantable temperature-sensitive formulations that drug release is accelerated by cooling at administered site. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Microcrystalline cellulose-carboxymethyl cellulose sodium as an effective dispersant for drug nanocrystals: A case study.

    Science.gov (United States)

    Dan, JiXiu; Ma, YueQin; Yue, PengFei; Xie, YuanBiao; Zheng, Qin; Hu, PengYi; Zhu, WeiFeng; Yang, Ming

    2016-01-20

    This study is aimed at seeking an alternative dispersant for spray drying of drug nanosuspensions. The ideal dispersant is not only able to prevent the agglomeration of drug nanocrystals in the suspension state, but also it is able to preserve redispersibility of drug nanocrystals after drying. An active pharmaceutical ingredient (API) was used as a model drug. API nanosuspensions were prepared by homogenization and converted into nanocrystals powder (API-NP) with microcrystalline cellulose-carboxymethyl cellulose sodium (MCCS) via spray drying. It was found that MCCS was able to prevent the aggregation of API-NP in the suspension state and the agglomeration during spray-drying process, possibility due to its high Zeta potential and steric barrier from network structure, and reduction of API size at nanoscale and incorporation into MCCS network structure did not affect the solid state of API as evidenced by DSC and XRD analysis. The spray-dried API-NP/MCCS powders exhibited excellent sphere-shape performance, and could easily redispersed to API-NC suspensions state. Dissolution of the spray-dried API-NP was distinctly superior to those of the crude powder and physical mixture, respectively. Within 30 min, approximate 85.87% of API was dissolved from the API-NP/MCCS. MCCS was demonstrated to be an effective dispersant for spray-dried drug nanocrystals and preservation of the nanocrystals associated with excellent redispersibility.

  13. Physicochemical of microcrystalline cellulose from oil palm fronds as potential methylene blue adsorbents.

    Science.gov (United States)

    Hussin, M Hazwan; Pohan, Nurul Aqilah; Garba, Zaharaddeen N; Kassim, M Jain; Rahim, Afidah Abdul; Brosse, Nicolas; Yemloul, Mehdi; Fazita, M R Nurul; Haafiz, M K Mohamad

    2016-11-01

    The present study sheds light on the physical and chemical characteristics of microcrystalline cellulose (MCC) isolated from oil palm fronds (OPF) pulps. It was found that the OPF MCC was identified as cellulose II polymorph, with higher crystallinity index than OPF α-cellulose (CrIOPFMCC: 71%>CrIOPFα-cellulose: 47%). This indicates that the acid hydrolysis allows the production of cellulose that is highly crystalline. BET surface area of OPF MCC was found to be higher than OPF α-cellulose (SBETOPFMCC: 5.64m(2)g(-1)>SBETOPFα-cellulose:Qa(0) 2.04m(2)g(-1)), which corroborates their potential as an adsorbent. In batch adsorption studies, it was observed that the experimental data fit well with Langmuir adsorption isotherm in comparison to Freundlich isotherm. The monolayer adsorption capacity (Qa(0)) of OPF MCC was found to be around 51.811mgg(-1) and the experimental data fitted well to pseudo-second-order kinetic model.

  14. 微晶纤维素的研究进展%Research progress of microcrystalline cellulose

    Institute of Scientific and Technical Information of China (English)

    吴伟兵; 庄志良; 景宜; 戴红旗

    2013-01-01

    Microcrystalline cellulose (MCC) is an important research area in material and polymer science because of their particular size and structure,and the abundant,renewable,biodegradable and biocompatible cellulose matrix.Acid hydrolysis and enzymatic hydrolysis are the main methods for preparing MCC.Besides the wide applications in traditional industries,MCC has important applications in the areas of reinforced composite,biomedicine,photoelectric science,etc.Finally,the future development of MCC is prospected.%微晶纤维素具有独特的尺寸结构,其基质纤维素丰富价廉、可再生降解并具有良好的生物相容性,是天然高分子材料的重要分支.微晶纤维素的制备方法主要有酸水解法和酶解法;微晶纤维素除在传统行业有广泛应用外,还在增强复合、生物医学和光电科学等新兴领域有重要应用.最后对微晶纤维素的未来发展进行了展望和期待.

  15. Effects of seed layer on the performance of microcrystalline silicon germanium solar cells

    Institute of Scientific and Technical Information of China (English)

    Cao Yu; Zhang Jianjun; Li Tianwei; Huang Zhenhua; Ma Jun; Yang Xu; Ni Jian

    2013-01-01

    Using plasma enhanced chemical vapor deposition (PECVD) at 13.56 MHz,a seed layer is fabricated at the initial growth stage of the hydrogenated microcrystalline silicon germanium (μc-Si1-xGex:H) i-layer.The effects of seeding processes on the growth of μc-Si 1-x Gex:H i-layers and the performance of μc-Si1-x Gex:H p-in single junction solar cells are investigated.By applying this seeding method,the μc-Si 1-xGex:H solar cell shows a significant improvement in short circuit current density (Jsc) and fill factor (FF) with an acceptable performance of blue response as a μc-Si:H solar cell even when the Ge content x increases up to 0.3.Finally,an improved efficiency of 7.05% is achieved for the μc-Sio.7Ge0.3:H solar cell.

  16. Melt-processed poly(vinyl alcohol) composites filled with microcrystalline cellulose from waste cotton fabrics.

    Science.gov (United States)

    Sun, Xunwen; Lu, Canhui; Liu, Yong; Zhang, Wei; Zhang, Xinxing

    2014-01-30

    Waste cotton fabrics (WCFs), which are generated in a large volume from the textile industry, have caused serious disposal problem. Recycling WCFs into value-added products is one of the vital measures for both environmental and economic benefits. In this study, microcrystalline cellulose (MCC) was prepared by acid hydrolysis of WCFs, and used as reinforcement for melt-processed poly(vinyl alcohol) (PVA) with water and formamide as plasticizer. The microstructure and mechanical properties of the melt-processed PVA/MCC composites were characterized by Fourier transform infrared spectra, Raman spectra, differential scanning calorimetry, thermal gravimetric analysis, X-ray diffraction, tensile tests and dynamic mechanical analysis. The results indicated that MCC could establish strong interfacial interaction with PVA through hydrogen bonding. As a result, the crystallization of PVA was confined and its melting temperature was decreased, which was beneficial for the melt-processing of PVA. Compared with the unfilled PVA, the PVA/MCC composites exhibited remarkable improvement in modulus and tensile strength.

  17. Iron Oxide Nanoparticles Employed as Seeds for the Induction of Microcrystalline Diamond Synthesis

    Directory of Open Access Journals (Sweden)

    Resto Oscar

    2008-01-01

    Full Text Available AbstractIron nanoparticles were employed to induce the synthesis of diamond on molybdenum, silicon, and quartz substrates. Diamond films were grown using conventional conditions for diamond synthesis by hot filament chemical vapor deposition, except that dispersed iron oxide nanoparticles replaced the seeding. X-ray diffraction, visible, and ultraviolet Raman Spectroscopy, energy-filtered transmission electron microscopy , electron energy-loss spectroscopy, and X-ray photoelectron spectroscopy (XPS were employed to study the carbon bonding nature of the films and to analyze the carbon clustering around the seed nanoparticles leading to diamond synthesis. The results indicate that iron oxide nanoparticles lose the O atoms, becoming thus active C traps that induce the formation of a dense region of trigonally and tetrahedrally bonded carbon around them with the ensuing precipitation of diamond-type bonds that develop into microcrystalline diamond films under chemical vapor deposition conditions. This approach to diamond induction can be combined with dip pen nanolithography for the selective deposition of diamond and diamond patterning while avoiding surface damage associated to diamond-seeding methods.

  18. Impact of microcrystalline cellulose material attributes: a case study on continuous twin screw granulation.

    Science.gov (United States)

    Fonteyne, Margot; Correia, Ana; De Plecker, Sofie; Vercruysse, Jurgen; Ilić, Ilija; Zhou, Qi; Vervaet, Chris; Remon, Jean Paul; Onofre, Fernanda; Bulone, Vincent; De Beer, Thomas

    2015-01-30

    The International Conference on Harmonisation (ICH) states in its Q8 'Pharmaceutical Development' guideline that the manufacturer of pharmaceuticals should have an enhanced knowledge of the product performance over a range of material attributes, manufacturing process options and process parameters. The present case study evaluates the effect of unspecified variability of raw material properties upon the quality attributes of granules; produced using a continuous from-powder-to-tablet wet granulation line (ConsiGma™ 25). The impact of different material attributes of six samples of microcrystalline cellulose (MCC) was investigated. During a blind study the different samples of MCC were used separately and the resulting granules were evaluated in order to identify the differences between the six samples. Variation in size distribution due to varying water binding capacity of the MCC samples was observed. The cause of this different water binding capacity was investigated and was caused by a different degree of crystallinity. Afterwards, an experimental design was conducted in order to evaluate the effect of both product and process variability upon the granule size distribution. This model was used in order to calculate the required process parameters to obtain a preset granule size distribution regardless of the type of MCC used. The difference in water binding capacity and its effect on granular properties was still present when combining the MCC grades with different binders. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Supercritical water treatment for cello-oligosaccharide production from microcrystalline cellulose.

    Science.gov (United States)

    Tolonen, Lasse K; Juvonen, Minna; Niemelä, Klaus; Mikkelson, Atte; Tenkanen, Maija; Sixta, Herbert

    2015-01-12

    Microcrystalline cellulose was treated in supercritical water at 380 °C and at a pressure of 250 bar for 0.2, 0.4, and 0.6s. The yield of the ambient-water-insoluble precipitate and its average molar mass decreased with an extended treatment time. The highest yield of 42 wt% for DP2-9 cello-oligosaccharides was achieved after the 0.4s treatment. The reaction products included also 11 wt% ambient-water-insoluble precipitate with a DP(w) of 16, and 6.1 wt% monomeric sugars, and 37 wt% unidentified degradation products. Oligo- and monosaccharide-derived dehydration and retro-aldol fragmentation products were analyzed via a combination of HPAEC-PAD-MS, ESI-MS/MS, and GC-MS techniques. The total amount of degradation products increased with treatment time, and fragmented (glucosyl(n)-erythrose, glucosyl(n)-glycolaldehyde), and dehydrated (glucosyl(n)-levoglucosan) were identified as the main oligomeric degradation products from the cello-oligosaccharides.

  20. Effect of substrate temperature on the growth and properties of boron-doped microcrystalline silicon films

    Institute of Scientific and Technical Information of China (English)

    Lei Qing-Song; Wu Zhi-Meng; Geng Xin-Hua; Zhao Ying; Sun Jian; Xi Jian-Ping

    2006-01-01

    Highly conductive boron-doped hydrogenated microcrystalline silicon (μc-Si:H) films are prepared by very high frequency plasma enhanced chemical vapour deposition (VHF PECVD) at the substrate temperatures (Ts) ranging from 90℃ to 270℃. The effects of Ts on the growth and properties of the films are investigated. Results indicate that the growth rate, the electrical (dark conductivity, carrier concentration and Hall mobility) and structural (crystallinity and grain size) properties are all strongly dependent on Ts. As Ts increases, it is observed that 1) the growth rate initially increases and then arrives at a maximum value of 13.3 nm/min at Ts=210℃, 2) the crystalline volume fraction (Xc) and the grain size increase initially, then reach their maximum values at Ts = 140℃, and finally decrease, 3) the dark conductivity (σd),carrier concentration and Hall mobility have a similar dependence on Tg and arrive at their maximum values at Ts=190℃. In addition, it is also observed that at a lower substrate temperature Ts, a higher dopant concentration is required in order to obtain a maximum σd.

  1. Modeling of triangular-shaped substrates for light trapping in microcrystalline silicon solar cells

    Science.gov (United States)

    Zi, Wei; Hu, Jian; Ren, Xiaodong; Ren, Xianpei; Wei, QingBo; Liu, Shengzhong (Frank)

    2017-01-01

    The influence of triangular grating used as a light trapping structure on the optical wave propagation within thin-film microcrystalline silicon (μc-Si:H) solar cells is investigated. A finite difference time domain (FDTD) approach is used to rigorously solve the Maxwell's equations in three dimensions. We apply two parameters of mean surface roughness (Sa) and slope (k) to define triangular structure and study their influence on the absorption of μc-Si:H. When Sa and k are set to 400 nm and 1, respectively, a largest enhancement of absorption is achieved. The optimum short circuit photocurrent (Jsc) of a 1-μm thick μc-Si:H solar cell made on such a textured substrate can reach 27.0 mA/cm2. The carrier generation rate in the μc-Si:H material is also rigorously analyzed. Finally, we identify some key optical losses in μc-Si:H solar cells and propose for further optimizing the device design.

  2. Effect of Mild Acid Hydrolysis Parameters on Properties of Microcrystalline Cellulose

    Directory of Open Access Journals (Sweden)

    Kari Mikael Vanhatalo

    2014-06-01

    Full Text Available The effects of mild kraft pulp hydrolysis conditions (reaction time, temperature, pulp consistency, and acid dosage with sulfuric acid (H2SO4 on the properties of microcrystalline cellulose (MCC were investigated. The degree of polymerization (DP of cellulose rapidly decreased at the initiation of hydrolysis and leveled off after a certain reaction time, depending on the hydrolysis conditions. The intensity of the hydrolysis treatment greatly affected the cellulose particle size. Compared to the intensive treatment, the mild conditions resulted in a broader particle size distribution, while smaller particles with a narrow size distribution were obtained under severe conditions. However, the particle size leveled off at a hydrolysis factor (P-factor of 300. The results suggest that after a certain P-factor (300, severe hydrolysis conditions have no advantage over mild ones as related to the MCC particle properties. Because of favourable reaction conditions (short delay time, moderate temperature, and small amounts of chemicals, this method can be implemented on an industrial scale in a chemical pulp mill.

  3. The Emitter Having Microcrystalline Surface in Silicon Heterojunction Interdigitated Back Contact Solar Cells

    Science.gov (United States)

    Ji, Kwang-sun; Syn, Hojung; Choi, Junghoon; Lee, Heon-Min; Kim, Donghwan

    2012-10-01

    In producing the Si heterojunction interdigitated backcontact solar cells, we investigated the feasibility of applying amorphous Si emitter having considerable crystalline Si phase at the facing to transparent conducting oxide (TCO) layer. Prior to evaluating electrical property, we characterized material nature of hydrogenated microcrystalline p-type silicon (µc-p-Si:H) as crystallized fraction, surface morphology, bonding kinds in thin films and then surface passivation quality finally. The diode and interface contact characteristics were induced by the simple test device and then current-voltage (I-V) curve showed more linearity in µc/hydrogenated amorphous silicon (a-Si:H) emitter case. We fabricated heterojunction back contact (HBC) solar cells using p/n interdigitated structure and acquired the 23.4% efficiency in cell size with performance parameters as open-circuit voltage (Voc) 723 mV, short-circuit current density (Jsc) 41.8 mA/cm2, fill factor (FF) 0.774, in the cell size (at 2×2 cm2).

  4. Performance of amorphous and microcrystalline silicon pin solar cells under variable light intensity

    Energy Technology Data Exchange (ETDEWEB)

    Nath, M.; Chakraborty, S.; Chatterjee, P. [Energy Research Unit, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032 (India); Kim, K.H.; Johnson, E.V.; Roca i Cabarrocas, P. [Laboratoire de Physique des Interfaces et des Couches Minces, Ecole Polytechnique, CNRS, 91128 Palaiseau (France)

    2010-04-15

    We have studied the solar cell behaviour under variable light intensity (VLI) of a standard a-Si:H pin solar cell with a wide band gap a-SiC:H emitter layer, and microcrystalline ({mu}c)-Si:H solar cells of different degrees of crystallinity, using experiments in conjunction with detailed electrical-optical modelling. Both experiments and modelling reveal that whereas the fill factor (FF) of the a-Si:H pin cell decreases with increasing light intensity, starting from a low applied light bias, that of the {mu}c-Si:H cells increases with light intensity over a major part of this range. This fact enables one to attain the maximum of the open-circuit voltage - fill factor product (V{sub oc} x FF) at 1 to 2 suns intensity for the latter case; however this is not achieved for the a-Si:H cell. Using modelling we try to understand this difference in behaviour of the FF under VLI for the two types of cells. We also predict under what conditions it would be possible to shift the (V{sub oc} x FF){sub max} for the a-Si:H cell towards one sun intensity. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  5. Use of hexamethyldisiloxane for p-type microcrystalline silicon oxycarbide layers

    Directory of Open Access Journals (Sweden)

    Goyal Prabal

    2016-01-01

    Full Text Available The use of hexamethyldisiloxane (HMDSO as an oxygen source for the growth of p-type silicon-based layers deposited by Plasma Enhanced Chemical Vapor Deposition is evaluated. The use of this source led to the incorporation of almost equivalent amounts of oxygen and carbon, resulting in microcrystalline silicon oxycarbide thin films. The layers were examined with characterisation techniques including Spectroscopic Ellipsometry, Dark Conductivity, Fourier Transform Infrared Spectroscopy, Secondary Ion Mass Spectrometry and Transmission Electron Microscopy to check material composition and structure. Materials studies show that the refractive indices of the layers can be tuned over the range from 2.5 to 3.85 (measured at 600 nm and in-plane dark conductivities over the range from 10-8 S/cm to 1 S/cm, suggesting that these doped layers are suitable for solar cell applications. The p-type layers were tested in single junction amorphous silicon p-i-n type solar cells.

  6. To prepare and characterize microcrystalline cellulose granules using water and isopropyl alcohol as granulating agents and determine its end-point by thermal and rheological tools.

    Science.gov (United States)

    Chaudhari, Smruti P; Dave, Rutesh H

    2015-05-01

    Microcrystalline cellulose (MCC-102) is one of the most commonly used excipient in the pharmaceutical industry. For this research purpose, authors have developed a different technique to determine the end point for MCC-102 using water and isopropyl alcohol 70% (IPA) as granulating agent. Wet and dry granules obtained were characterized for their flow properties using the powder rheometer and thermal analysis. Powder rheometer was used to measure basic flowability energy (BFE), specific energy (SE), percentage compressibility, permeability and aeration. Thermal analysis includes effusivity and differential scanning calorimetry (DSC) measurements. BFE and SE results showed water granules requires high energy as compared to IPA granules. Permeability and compressibility results suggest IPA forms more porous granules and have better compressibility as compared to water granules. Hardness data reveals interesting phenomena in which as the amount of water increases, hardness decreases and vice-versa for IPA. Optimal granules were obtained in the range of 45-55% w/w. DSC data supported the formation of optimal granules. Empirical measurements like angle of repose did not reveal any significant differences between powder flow among various granules. In this paper, with the help of thermal effusivity and powder rheology we were able to differentiate between various powder flows and determine the optimal range for granule formation.

  7. Hot-wire chemical vapor deposition prepared aluminum doped p-type microcrystalline silicon carbide window layers for thin film silicon solar cells

    Science.gov (United States)

    Chen, Tao; Köhler, Florian; Heidt, Anna; Carius, Reinhard; Finger, Friedhelm

    2014-01-01

    Al-doped p-type microcrystalline silicon carbide (µc-SiC:H) thin films were deposited by hot-wire chemical vapor deposition at substrate temperatures below 400 °C. Monomethylsilane (MMS) highly diluted in hydrogen was used as the SiC source in favor of SiC deposition in a stoichiometric form. Aluminum (Al) introduced from trimethylaluminum (TMAl) was used as the p-type dopant. The material property of Al-doped p-type µc-SiC:H thin films deposited with different deposition pressure and filament temperature was investigated in this work. Such µc-SiC:H material is of mainly cubic (3C) SiC polytype. For certain conditions, like high deposition pressure and high filament temperature, additional hexagonal phase and/or stacking faults can be observed. P-type µc-SiC:H thin films with optical band gap E04 ranging from 2.0 to 2.8 eV and dark conductivity ranging from 10-5 to 0.1 S/cm can be prepared. Such transparent and conductive p-type µc-SiC:H thin films were applied in thin film silicon solar cells as the window layer, resulting in an improved quantum efficiency at wavelengths below 480 nm.

  8. Microcrystalline cellulose, a useful alternative for sucrose as a matrix former during freeze-drying of drug nanosuspensions - a case study with itraconazole.

    Science.gov (United States)

    Van Eerdenbrugh, Bernard; Vercruysse, Sofie; Martens, Johan A; Vermant, Jan; Froyen, Ludo; Van Humbeeck, Jan; Van den Mooter, Guy; Augustijns, Patrick

    2008-10-01

    Itraconazole nanosuspensions, stabilized with 10% TPGS (relative to the weight of itraconazole), were transformed into nanoparticulate powders by freeze-drying. The crystalline itraconazole nanoparticles showed peak broadening in the X-ray powder diffraction spectra and a lower melting point as inferred from differential scanning calorimetry. As it was found that freeze-drying compromised dissolution behavior, sucrose was added as a matrix, former (50,100 and 200%, relative to the weight of itraconazole). Higher amounts of sucrose unexpectedly resulted in a decrease in the dissolution rate. After thorough evaluation of the powders, it was found that whereas higher sucrose content showed a cryoprotective effect, agglomeration during the final phase of the subsequent drying step tended to increase with higher amounts of sucrose. Therefore, microcrystalline cellulose (MCC) was evaluated as an alternative matrix former. The inclusion of MCC resulted in fast dissolution that increased with increasing amounts of MCC [for powders containing 50%,100% and 200% MCC, (relative to the weight of itraconazole), the times required for 63.2% release were 10.5+/-0.7, 6.4+/-1.2 and 3.1+/-0.5min, respectively]. The dissolution profiles showed an initial phase of burst dissolution, followed by a phase of slower release. As the fraction showing burst dissolution increased with higher MCC content, the system holds promise to maintain the dissolution enhancing properties of nanoparticles in the dry form.

  9. [Quality by design based high shear wet granulation process development for the microcrystalline cellulose].

    Science.gov (United States)

    Luo, Gan; Xu, Bing; Sun, Fei; Cui, Xiang-long; Shi, Xin-yuan; Qiao, Yan-jiang

    2015-03-01

    The design space of the high shear wet granulation process was established and validated within the framework of quality by design (QbD). The system of microcrystalline cellulose-de-ioned water was used in this study. The median granule size and bulk density of granules were identified as critical quality attributes. Plackeet-Burmann experimental design was used to screen these factors as follows: dry mixing time, the impeller and chopper speed of dry mixing, water amount, water addition time, wet massing time, the impeller and chopper speed of wet massing and drying time. And the optimization was implemented with the central composite experimental design based on screened critical process parameters. The design space of the high shear wet granulation process was established based on the quadratic polynomial regression model. Since the P-values of both models were less than 0.05 and values of lack of fit were more than 0.1, the relationship between critical quality attributes and critical process parameters could be well described by the two models. The reliability of design space, illustrated by overlay plot, was improved with the addition of 95% confidence interval. For those granules whose process parameters were in the design space, the granule size could be controlled within 250 to 355 μm, and the bulk density could be controlled within a range of 0.4 to 0.6 g x cm(-3). The robustness and flexibility of the high shear wet granulation process have been enhanced via the establishment of the design space based on the QbD concept.

  10. Effect of phosphoric acid pretreatment on enzymatic hydrolysis of microcrystalline cellulose.

    Science.gov (United States)

    Zhang, Juanhua; Zhang, Beixiao; Zhang, Jingqiang; Lin, Lu; Liu, Shijie; Ouyang, Pingkai

    2010-01-01

    Microcrystalline cellulose (MCC) was pretreated with phosphoric acid at 323K for 10h. X-ray diffraction (XRD) and Atomic Force Microscope (AFM) analyses revealed that the fiber surface morphology of pretreated MCC (P-MCC) were uneven and rough with the crystalline diffraction peaks of P-MCC decreased to a distinct range. The X-ray Photoelectron Spectroscopy (XPS) analysis showed that the uneven and rough surface of P-MCC could enhance the adsorption of cellulose to the molecular surface of cellulose, which is one of the key factors affecting enzymatic hydrolysis of cellulose. A reversible first order kinetics was employed to describe the adsorption kinetics of cellulase to MCC and P-MCC, and the adsorption rate constants of MCC and P-MCC were found to be 0.016, 0.024, 0.041, and 0.095, 0.149, 0.218min(-1), respectively at 278K, 293K and 308K. The activation energies of MCC and P-MCC hydrolysis reactions were found to be 22.257 and 19.721kJ mol(-1). The major hydrolysis products of MCC and P-MCC were cellobiose and glucose. Hydrolysis of MCC for 120h resulted in yields of glucose (7.21%), cellobiose (13.16%) and total sugars (20.37%). However, after the pretreatment with phosphoric acid, the corresponding sugar yields resulted from enzymatic hydrolysis of P-MCC were increased to 24.10%, 41.42%, and 65.52%; respectively, which were 3.34, 3.15, and 3.22 times of the sugars yields from enzymatic hydrolysis of MCC. Copyright 2010 Elsevier Inc. All rights reserved.

  11. Electrochemical properties and applications of nanocrystalline, microcrystalline, and epitaxial cubic silicon carbide films.

    Science.gov (United States)

    Zhuang, Hao; Yang, Nianjun; Zhang, Lei; Fuchs, Regina; Jiang, Xin

    2015-05-27

    Microstructures of the materials (e.g., crystallinitiy, defects, and composition, etc.) determine their properties, which eventually lead to their diverse applications. In this contribution, the properties, especially the electrochemical properties, of cubic silicon carbide (3C-SiC) films have been engineered by controlling their microstructures. By manipulating the deposition conditions, nanocrystalline, microcrystalline and epitaxial (001) 3C-SiC films are obtained with varied properties. The epitaxial 3C-SiC film presents the lowest double-layer capacitance and the highest reversibility of redox probes, because of its perfect (001) orientation and high phase purity. The highest double-layer capacitance and the lowest reversibility of redox probes have been realized on the nanocrystalline 3C-SiC film. Those are ascribed to its high amount of grain boundaries, amorphous phases and large diversity in its crystal size. Based on their diverse properties, the electrochemical performances of 3C-SiC films are evaluated in two kinds of potential applications, namely an electrochemical capacitor using a nanocrystalline film and an electrochemical dopamine sensor using the epitaxial 3C-SiC film. The nanocrystalline 3C-SiC film shows not only a high double layer capacitance (43-70 μF/cm(2)) but also a long-term stability of its capacitance. The epitaxial 3C-SiC film shows a low detection limit toward dopamine, which is one to 2 orders of magnitude lower than its normal concentration in tissue. Therefore, 3C-SiC film is a novel but designable material for different emerging electrochemical applications such as energy storage, biomedical/chemical sensors, environmental pollutant detectors, and so on.

  12. SUBSTRATE EFFECT ON HYDROGENATED MICROCRYSTALLINE SILICON FILMS DEPOSITED WITH VHF-PECVD TECHNIQUE

    Institute of Scientific and Technical Information of China (English)

    H.D. Yang

    2006-01-01

    Raman spectra and scanning electron microscope (SEM) techniques were used to determine the structural properties of microcrystalline silicon (μc-Si:H) films deposited on different substrates with the very high frequency plasma-enhanced chemical vapor deposition ( VHF-PECVD )technique. Using the Raman spectra, the values of crystalline volume fraction Xc and average grain size d are 86%, 12.3nm; 65%, 5.45nm; and 38%, 4.05nm, for single crystalline silicon wafer,corning 7059 glass, and general optical glass substrates, respectively. The SEM images further demonstrate the substrate effect on the film surface roughness. For the single crystalline silicon wafer and Corning 7059 glass, the surfaces of the μc-Si:H films are fairly smooth because of the homogenous growth or little lattice mismatch. But for general optical glass, the surface of the μc-Si:H film is very rough, thus the growing surface roughness affects the crystallization process and determines the average grain size of the deposited material. Moreover, with the measurements of thickness, photo and dark conductivity, photosensitivity and activation energy, the substrate effect on the deposition rate, optical and electrical properties of the μc-Si:H thin films have also been investigated. On the basis of the above results, it can be concluded that the substrates affect the initial growing layers acting as a seed for the formation of a crystalline-like material, and then the deposition rates, optical and electrical properties are also strongly influenced, hence,deposition parameter optimization is the key method that can be used to obtain a good initial growing layer, to realize the deposition of μc-Si:H films with device-grade quality on cheap substrates such as general glass.

  13. Factors limiting the open-circuit voltage in microcrystalline silicon solar cells

    Directory of Open Access Journals (Sweden)

    Chatterjee P.

    2011-11-01

    Full Text Available In studying photovoltaic devices made with silicon thin films and considering them according to their grain size, it is curious that as the crystalline fraction increases, the open-circuit voltage (Voc – rather than approaching that of the single-crystal case – shows a decline. To gain an insight into this behavior, observed in hydrogenated microcrystalline silicon (μc-Si:H solar cells prepared under a variety of deposition conditions, we have used a detailed electrical-optical computer modeling program, ASDMP. Two typical μc-Si:H cells with low (~79% and higher (~93% crystalline volume fractions (Fc, deposited in our laboratory and showing this general trend, were modeled. From the parameters extracted by simulation of their experimental current density – voltage and quantum efficiency characteristics, it was inferred that the higher Fc cell has both a higher band gap defect density as well as a lower band gap energy. Our calculations reveal that the proximity of the quasi-Fermi levels to the energy bands in cells based on highly crystallized μc-Si:H (assumed to have a lower band gap, results in both higher free and trapped carrier densities. The trapped hole population, that is particularly high near the P/I interface, results in a strong interface field, a collapse of the field in the volume, and hence a lower open-circuit voltage. Interestingly enough, we were able to fabricate fluorinated μc-Si:H:F cells having 100% crystalline fraction as well as very large grains, that violate the general trend and show a higher Voc. Modeling indicates that this is possible for the latter case, as also for a crystalline silicon PN cell, in spite of a sharply reduced band gap, because the lower effective density of states at the band edges and a sharply reduced gap defect density overcome the effect of the lower band gap.

  14. Disilane as a growth rate catalyst of plasma deposited microcrystalline silicon thin films

    Energy Technology Data Exchange (ETDEWEB)

    Dimitrakellis, P.; Amanatides, E., E-mail: lef@plasmatech.gr; Mataras, D. [Department of Chemical Engineering, Plasma Technology Laboratory, University of Patras, P.O. Box 140, 26504 Patras (Greece); Kalampounias, A. G. [University of Ioannina, Dep. of Chemistry, 45110, Ioannina (Greece); Spiliopoulos, N. [Department of Physics, University of Patras, P.O. Box 140, 26504 Patras (Greece); Lahootun, V.; Coeuret, F.; Madec, A. [Air Liquide CRCD,1 chemin de la porte des Loges, Les Loges en Josas, 78354 Jouy en Josas (France)

    2016-07-15

    The effect of small disilane addition on the gas phase properties of silane-hydrogen plasmas and the microcrystalline silicon thin films growth is presented. The investigation was conducted in the high pressure regime and for constant power dissipation in the discharge with the support of plasma diagnostics, thin film studies and calculations of discharge microscopic parameters and gas dissociation rates. The experimental data and the calculations show a strong effect of disilane on the electrical properties of the discharge in the pressure window from 2 to 3 Torr that is followed by significant raise of the electron number density and the drop of the sheaths electric field intensity. Deposition rate measurements show an important four to six times increase even for disilane mole fractions as low as 0.3 %. The deposition rate enhancement was followed by a drop of the material crystalline volume fraction but films with crystallinity above 40 % were deposited with different combinations of total gas pressure, disilane and silane molar ratios. The enhancement was partly explained by the increase of the electron impact dissociation rate of silane which rises by 40% even for 0.1% disilane mole fraction. The calculations of the gas usage, the dissociation and the deposition efficiencies show that the beneficial effect on the growth rate is not just the result of the increase of Si-containing molecules density but significant changes on the species participating to the deposition and the mechanism of the film growth are caused by the disilane addition. The enhanced participation of the highly sticking to the surface radical such as disilylene, which is the main product of disilane dissociation, was considered as the most probable reason for the significant raise of the deposition efficiency. The catalytic effect of such type of radical on the surface reactivity of species with lower sticking probability is further discussed, while it is also used to explain the restricted

  15. Amorphous and microcrystalline silicon applied in very thin tandem solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Schicho, Sandra

    2011-07-28

    Thin-film solar cells are fabricated by low-cost production processes, and are therefore an alternative to conventionally used wafer solar cells based on crystalline silicon. Due to the different band gaps, tandem cells that consist of amorphous (a-Si:H) and microcrystalline ({mu}c-Si:H) single junction solar cells deposited on top of each other use the solar spectrum much more efficient than single junction solar cells. The silicon layers are usually deposited on TCO (Transparent Conductive Oxide)-coated glass and metal- or plastic foils. Compared to the CdTe and CIGS based thin-film technologies, silicon thin-film solar cells have the advantage that no limitation of raw material supply is expected and no toxic elements are used. Nevertheless, the production cost per Wattpeak is the decisive factor concerning competitiveness and can be reduced by, e.g., shorter deposition times or reduced material consumption. Both cost-reducing conceptions are simultaneously achieved by reducing the a-Si:H and {mu}c-Si:H absorber layer thicknesses in a tandem device. In the work on hand, the influence of an absorber layer thickness reduction up to 77% on the photovoltaic parameters of a-Si:H/{mu}c-Si:H tandem solar cells was investigated. An industry-oriented Radio Frequency Plasma-Enhanced Chemical Vapour Deposition (RF-PECVD) system was used to deposit the solar cells on glass substrates coated with randomly structured TCO layers. The thicknesses of top and bottom cell absorber layers were varied by adjusting the deposition time. Reduced layer thicknesses lead to lower absorption and, hence, to reduced short-circuit current densities which, however, are partially balanced by higher open-circuit voltages and fill factors. Furthermore, by using very thin amorphous top cells, the light-induced degradation decreases tremendously. Accordingly, a thickness reduction of 75% led to an efficiency loss of only 21 %. By adjusting the parameters for the deposition of a-Si:H top cells, a

  16. 芦笋皮微晶纤维素的制备%Preparation of microcrystalline cellulose from asparagus peel

    Institute of Scientific and Technical Information of China (English)

    宋美玲

    2012-01-01

    以芦笋皮为原料,酶法制得膳食纤维后,采用盐酸水解,以溶胀性为指标确定制备微晶纤维素的工艺条件,为芦笋皮的加工利用提供一个新的途径。试验结果表明:在75℃下,盐酸浓度4 mol/L,料酸比1g∶5 mL,酸解时间5 h,制备出的微晶纤维素溶胀性可达6.90 mL/g,比芦笋皮中膳食纤维的溶胀性(4.80 mL/g)高2.10 mL/g。%Using asparagus as raw materials,microcrystalline cellulose was prepared in the best experimental conditions,determined by hydrochloric acid in different acidolysis time,acid concentration and proportion of material to acid,which took swelling as an index.And the best experimental conditions for preparation of microcrystalline cellulose provides a new way to process the asparagus.The results show that the best preparation conditions were the concentration of hydrochloric acid 4 mol/L,the proportion of material to acid 1∶5,acidolysis time 5 h,at 75 ℃.In the above conditions,the swelling of microcrystalline cellulose can be up to 6.90 mL/g,which is 2.10 mL/g more than the swelling(4.80 mL/g)of dietary fiber from the asparagus peel.

  17. The effect of pulping concentration treatment on the properties of microcrystalline cellulose powder obtained from waste paper.

    Science.gov (United States)

    Okwonna, Okumneme O

    2013-10-15

    Microcrystalline cellulose (MCC) powder was isolated from three grades of waste paper: book, Groundwood/Newsprint and paperboard, through the processes of pulping and hydrolysis. Pulping treatment on these grades of waste paper was done using varying concentrations of caustic soda. Effects of the concentration of the pulping medium on the thermal and kinetic properties were investigated. Also determined were the effects of this on the physico-chemical properties. The chemical structure was characterized using an infrared spectroscopy (FTIR). Results showed these properties to be affected by the concentration of the pulping medium. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. [Tableting technology of a dry extract from Solidago virgaurea L. with the use of silicified microcrystalline cellulose (Prosolv) and other selected auxiliary substances].

    Science.gov (United States)

    Marczyiński, Zbigniew

    2009-01-01

    Direct tableting is simpler and more cost-effective from the point of view of good manufacturing practice (GMP) than wet granulation or dry compacting. Moreover, the use of dry plant extracts in the process of direct tableting, omitting granulation, decreases the possibility of biological activity loss of active substances. Thus, pharmaceutical industry uses this particular process more and more frequently. Only few therapeutic substances form under compression tablets meeting current requirements. Very often addition of auxiliary substances appears to be indispensable. The aim of this study was to obtain uncoated tablets by the method of direct tableting with the use of selected auxiliary substances. Dry extract from Solidago virgaurea L. was the study material. Shrimp chitosan, silicified microcrystalline cellulose (Prosolv), polyvinylpyrrolidone, calcium carbonate and sodium stearyl fumarate were used as auxiliary substances. Eleven tablet batches were manufactured in a reciprocating instrumented tableting machine (Ewreka). The produced tablets were subjected to morphological tests comprising the tablet size, determination of batching accuracy (determination of mass uniformity of individual tablets), test of mechanical resistance (crushing strength), determination of disintegration time. The statistical hardness of the manufactured tablets was also estimated. Pharmaceutical availability tests were performed of the biologically active substances released from tablets to the acceptor fluid. The study was based on general and detailed regulations of Polish Pharmacopoeia VII (PP VII). The obtained results allow to conclude that the applied auxiliary substances appeared to be useful in adequate proportions in manufacturing tablets containing dry extract from Solidago virgaurea L. The properties of the obtained batches of tablets were in majority consistent with the current requirements. The applied method provides technological reproducibility and high durability of

  19. Microcrystalline hexagonal tungsten bronze. 1. Basis of ion exchange selectivity for cesium and strontium.

    Science.gov (United States)

    Griffith, Christopher S; Luca, Vittorio; Hanna, John V; Pike, Kevin J; Smith, Mark E; Thorogood, Gordon S

    2009-07-06

    The structural basis of selectivity for cesium and strontium of microcrystalline hexagonal tungsten bronze (HTB) phase Na(x)WO(3+x/2).zH(2)O has been studied using X-ray and neutron diffraction techniques, 1D and 2D (23)Na magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy, and radiochemical ion exchange investigations. For the HTB system, this study has shown that scattering techniques alone provide an incomplete description of the disorder and rapid exchange of water (with tunnel cations) occurring in this system. However, 1D and 2D (23)Na MAS NMR has identified three sodium species within the HTB tunnels-species A, which is located at the center of the hexagonal window and is devoid of coordinated water, and species B and C, which are the di- and monohydrated variants, respectively, of species A. Although species B accords with the traditional crystallographic model of the HTB phase, this work is the first to propose and identify the anhydrous species A and monohydrate species C. The population (total) of species B and C decreases in comparison to that of species A with increasing exchange of either cesium or strontium; that is, species B and C appear more exchangeable than species A. Moreover, a significant proportion of tunnel water is redistributed by these cations. Multiple ion exchange investigations with radiotracers (137)Cs and (85)Sr have shown that for strontium there is a definite advantage in ensuring that any easily exchanged sodium is removed from the HTB tunnels prior to exchange. The decrease in selectivity (wrt cesium) is most probably due to the slightly smaller effective size of Sr(2+); namely, it is less of a good fit for the hexagonal window, ion exchange site. The selectivity of the HTB framework for cesium has been shown unequivocally to be defined by the structure of the hexagonal window, ion exchange site. Compromising the geometry of this window even in the slightest way by either (1) varying the cell volume through

  20. Amorphous-to-microcrystalline transition in a-Si:H under hydrogen plasma: Optical and electrical detection

    Energy Technology Data Exchange (ETDEWEB)

    Hadjadj, Aomar; Larbi, Fadila [Groupe de Recherche en Sciences pour l' Ingenieur (GRESPI), Universite de Reims, 51687 Reims cedex 2 (France); Pham, Nans [Groupe de Recherche en Sciences pour l' Ingenieur (GRESPI), Universite de Reims, 51687 Reims cedex 2 (France); Laboratoire de Physique des Interfaces et Couches Minces (LPICM), Ecole Polytechnique, 91128 Palaiseau (France); Roca i Cabarrocas, Pere [Laboratoire de Physique des Interfaces et Couches Minces (LPICM), Ecole Polytechnique, 91128 Palaiseau (France)

    2012-06-15

    The exact role of hydrogen in the crystallization process is still a subject of broad controversies due to the complexity of the overall plasma enhanced chemical vapor deposition (PECVD) process. We have investigated by ellipsometry the amorphous-to-microcrystalline the phase transition in intrinsic and doped hydrogenated amorphous silicon (a-Si:H) thin films during their exposure to a hydrogen plasma in conditions of chemical transport. The whole ellipsometry diagnostics reveal that, while intrinsic and phosphorus-doped a-Si:H present a similar trend during the plasma treatment, boron-doped a-Si:H differs by special features such as a rapid formation of the hydrogen-rich subsurface layer and an early amorphous-to-microcrystalline phase transition. The particular behavior of boron-doped material is also pointed out through the time-evolution of the self-bias voltage on the radio-frequency electrode during the hydrogen plasma treatment (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Influence of alkaline hydrogen peroxide pre-hydrolysis on the isolation of microcrystalline cellulose from oil palm fronds.

    Science.gov (United States)

    Owolabi, Abdulwahab F; Haafiz, M K Mohamad; Hossain, Md Sohrab; Hussin, M Hazwan; Fazita, M R Nurul

    2017-02-01

    In the present study, microcrystalline cellulose (MCC) was isolated from oil palm fronds (OPF) using chemo-mechanical process. Wherein, alkaline hydrogen peroxide (AHP) was utilized to extract OPF fibre at different AHP concentrations. The OPF pulp fibre was then bleached with acidified sodium chlorite solution followed by the acid hydrolysis using hydrochloric acid. Several analytical methods were conducted to determine the influence of AHP concentration on thermal properties, morphological properties, microscopic and crystalline behaviour of isolated MCC. Results showed that the MCC extracted from OPF fibres had fibre diameters of 7.55-9.11nm. X-ray diffraction (XRD) analyses revealed that the obtained microcrystalline fibre had both celluloses I and cellulose II polymorphs structure, depending on the AHP concentrations. The Fourier transmission infrared (FTIR) analyses showed that the AHP pre-hydrolysis was successfully removed hemicelluloses and lignin from the OPF fibre. The crystallinity of the MCC was increased with the AHP concentrations. The degradation temperature of MCC was about 300°C. The finding of the present study showed that pre-treatment process potentially influenced the quality of the isolation of MCC from oil palm fronds. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Production of Starch Based Bioplastic from Cassava Peel Reinforced with Microcrystalline Celllulose Avicel PH101 Using Sorbitol as Plasticizer

    Science.gov (United States)

    Maulida; Siagian, M.; Tarigan, P.

    2016-04-01

    The production of starch based bioplastics from cassava peel reeinforced with microcrystalline cellulose using sorbitol as plasticizer were investigated. Physical properties of bioplastics were determined by density, water uptake, tensile strength and Fourier Transform Infrared Spectroscopy. Bioplastics were prepared from cassava peel starch plasticized using sorbitol with variation of 20; 25; 30% (wt/v of sorbitol to starch) reinforced with microcrystalline celllulose (MCC) Avicel PH101 fillers with range of 0 to 6% (wt/wt of MCC to starch). The results showed improvement in tensile strength with higher MCC content up to 9, 12 mpa compared to non-reinforced bioplastics. This could be mainly attributed to the strong hydrogen bonds between MCC and starch. On the contrary, the addition of MCC decreased the elongation at break, density and water uptake. Fourier Transform Infrared Spectroscopy showed the functional groups of bioplastics, which the majority of O-H groups were found at the bioplastics with reinforcing filler MCC that represented substantial hydrogen bonds. The highest tensile strength value was obtained for bioplastic with MCC content 6% and sorbitol content 20%. With good adhesion between MCC and starch the production of bioplastics could be widely used as a substitute for conventional plastics with more benefits to the environment.

  3. AFM and FTIR characterization of microcrystalline Si obtained from isothermal annealing of Al/a-Si:H

    Energy Technology Data Exchange (ETDEWEB)

    Rojas-Lopez, M.; Orduna-Diaz, A.; Delgado-Macuil, R. [Centro de Investigacion en Biotecnologia Aplicada (CIBA), IPN, Tlaxcala, Tlax. 72197 (Mexico); Olvera-Hernandez, J. [Centro de Investigacion en Dispositivos Semiconductores (CIDS), BUAP, Puebla, Pue. 72570 (Mexico); Navarro-Contreras, H.; Vidal, M.A.; Saucedo, N.; Mendez-Garcia, V.H. [Instituto de Investigacion en Comunicacion Optica (IICO), UASLP, San Luis Potosi, S.L.P. 78100 (Mexico)

    2007-04-15

    Atomic force microscopy and Fourier transform infrared spectroscopy were used to investigate the morphology of the microcrystalline surface, and also the amorphous-crystalline structural transformation of a-Si:H films, isothermally annealed during several hours. Crystallization process was strongly influenced by the deposition of an Al layer on the surface of a-Si:H samples. Representative AFM images show the presence of grains, which increase in diameter with the annealing time. Relative crystallized fraction as a function of the annealing time can be described adequately by using the Avrami equation. The kinetic of this crystallization process suggest a two-dimensional growth of the Si nuclei. Fourier transform infrared measurements show the presence of an intense band near 512 cm{sup -1} associated to Si-Si bonding. We observed the relative diminishing of the intensity of the Si-H wagging mode at 694 cm{sup -1} with annealing time, suggesting effusion of hydrogen to the surface of microcrystalline films. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  4. Deposition and characterization of amorphous silicon with embedded nanocrystals and microcrystalline silicon for thin film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Ambrosio, R., E-mail: rambrosi@uacj.mx [Instituto Nacional de Astrofísica, Óptica y Electrónica, INAOE, Puebla (Mexico); Instituto de Ingeniería y Tecnología, Universidad Autónoma de Ciudad Juárez, UACJ, C.J., Chihuahua (Mexico); Moreno, M.; Torres, A. [Instituto Nacional de Astrofísica, Óptica y Electrónica, INAOE, Puebla (Mexico); Carrillo, A. [Instituto de Ingeniería y Tecnología, Universidad Autónoma de Ciudad Juárez, UACJ, C.J., Chihuahua (Mexico); Vivaldo, I.; Cosme, I. [Instituto Nacional de Astrofísica, Óptica y Electrónica, INAOE, Puebla (Mexico); Heredia, A. [Universidad Popular Autónoma del Estado de Puebla, Puebla (Mexico)

    2015-09-15

    Highlights: • Nanostructured silicon thin films were deposited by PECVD. • Polymorphous and microcrystalline were obtained varying the pressure and power. • Structural and optoelectronics properties were studied. • The σ{sub dark} changed by 5 order of magnitude under illumination, V{sub d} was at 2.5 A/s. • The evidence of embedded nanocrystals into the amorphous matrix was investigated. - Abstract: Amorphous silicon thin films with embedded nanocrystals and microcrystalline silicon were deposited by the standard Radio Frequency (RF) Plasma Enhanced Chemical Vapor Deposition (PECVD) technique, from SiH{sub 4}, H{sub 2}, Ar gas mixture at substrate temperature of 200 °C. Two series of films were produced varying deposition parameters as chamber pressure and RF power density. The chemical bonding in the films was characterized by Fourier transform infrared spectroscopy, where it was observed a correlation between the hydrogen content and the morphological and electrical properties in the films. Electrical and optical parameters were extracted in both series of films, as room temperature conductivity (σ{sub RT}), activation energy (E{sub a}), and optical band gap (E{sub g}). As well, structural analysis in the films was performed by Raman spectroscopy and Atomic Force Microscopy (AFM), which gives an indication of the films crystallinity. The photoconductivity changed in a range of 2 and 6 orders of magnitude from dark to AM 1.5 illumination conditions, which is of interest for thin film solar cells applications.

  5. Correlation Between the Raman Crystallinity of p-Type Micro-Crystalline Silicon Layer and Open Circuit Voltage of n-i-p Solar Cells.

    Science.gov (United States)

    Jung, Junhee; Kim, Sunbo; Park, Jinjoo; Shin, Chonghoon; Pham, Duy Phong; Kim, Jiwoong; Chung, Sungyoun; Lee, Youngseok; Yi, Junsin

    2015-10-01

    This article mainly discusses the difference between p-i-n and n-i-p type solar cells. Their structural difference has an effect on cell performance, such as open circuit voltage and fill factor. Although the deposition conditions are the same for both p-i-n and n-i-p cases, the substrate layers for depositing p-type microcrystalline silicon layers differ. In n-i-p cells, the substrate layer is p-type amorphous silicon oxide layer; whereas, in p-i-n cells, the substrate layer is ZnO:Al. The interfacial change leads to a 12% difference in the crystallinity of the p-type microcrystalline silicon layers. When the p-type microcrystalline silicon layer's crystallinity was not sufficient to activate an internal electric field, the open circuit voltage and fill factor decreased 0.075 V and 7.36%, respectively. We analyzed this problem by comparing the Raman spectra, electrical conductivity, activation energy and solar cell performance. By adjusting the thickness of the p-type microcrystalline silicon layer, we increased the open circuit voltage of the n-i-p cell from 0.835 to 0.91 V.

  6. Teaching Form as Form

    DEFF Research Database (Denmark)

    Keiding, Tina Bering

    2012-01-01

    understanding of form per se, or, to use an expression from this text, of form as form. This challenge can be reduced to one question: how can design teaching support students in achieving not only the ability to recognize and describe different form-related concepts in existing design (i.e. analytical...... 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....... In general, students enter design education as far more skilled observers with regards to function than form. They are, in other words, predisposed to observe objects asking ‘what is?’, rather than ‘how is?’. This habit has not only cognitive implications. It is closely intertwined with a rudimentary...

  7. Teaching Form as Form

    DEFF Research Database (Denmark)

    Keiding, Tina Bering

    2012-01-01

    understanding of form per se, or, to use an expression from this text, of form as form. This challenge can be reduced to one question: how can design teaching support students in achieving not only the ability to recognize and describe different form-related concepts in existing design (i.e. analytical...... 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...... vocabulary of form. Even in cases in which teaching uses terms and phrases from everyday life (for instance, ‘intersection’), the meaning of the word cannot necessarily be transmitted directly from an ordinary vocabulary into a design context. And it is clearly a common issue for the contributions...

  8. Preliminary viability studies of fibroblastic cells cultured on microcrystalline and nanocrystalline diamonds produced by chemical vapour deposition method

    Directory of Open Access Journals (Sweden)

    Ana Amélia Rodrigues

    2012-01-01

    Full Text Available Implant materials used in orthopedics surgery have demonstrated some disadvantages, such as metallic corrosion processes, generation of wear particles, inflammation reactions and bone reabsorption in the implant region. The diamond produced through hot-filament chemical vapour deposition method is a new potential biomedical material due to its chemical inertness, extreme hardness and low coefficient of friction. In the present study we analysis two samples: the microcrystalline diamond and the nanocrystalline diamond. The aim of this study was to evaluate the surface properties of the diamond samples by scanning electron microscopy, Raman spectroscopy and atomic force microscopy. Cell viability and morphology were assessed using thiazolyl blue tetrazolium bromide, cytochemical assay and scanning electron microscopy, respectively. The results revealed that the two samples did not interfere in the cell viability, however the proliferation of fibroblasts cells observed was comparatively higher with the nanocrystalline diamond.

  9. Preliminary viability studies of fibroblastic cells cultured on microcrystalline and nanocrystalline diamonds produced by chemical vapour deposition method

    Directory of Open Access Journals (Sweden)

    Ana Amélia Rodrigues

    2013-02-01

    Full Text Available Implant materials used in orthopedics surgery have demonstrated some disadvantages, such as metallic corrosion processes, generation of wear particles, inflammation reactions and bone reabsorption in the implant region. The diamond produced through hot-filament chemical vapour deposition method is a new potential biomedical material due to its chemical inertness, extreme hardness and low coefficient of friction. In the present study we analysis two samples: the microcrystalline diamond and the nanocrystalline diamond. The aim of this study was to evaluate the surface properties of the diamond samples by scanning electron microscopy, Raman spectroscopy and atomic force microscopy. Cell viability and morphology were assessed using thiazolyl blue tetrazolium bromide, cytochemical assay and scanning electron microscopy, respectively. The results revealed that the two samples did not interfere in the cell viability, however the proliferation of fibroblasts cells observed was comparatively higher with the nanocrystalline diamond.

  10. MORPHOLOGY, IN VITRO - DEGRADATION AND DRUG RELEASE PROFILE OF POLY (ETHYLENE-CO-VINYL ACETATE / MICROCRYSTALLINE CELLULOSE ACETATE

    Directory of Open Access Journals (Sweden)

    K. Lakshmi Narayana

    2011-06-01

    Full Text Available Microcrystalline cellulose acetate (MCC was incorporated in poly (ethylene-co-vinyl acetate (EVA at different loading. The morphology, swelling properties and drug release profile were studied with respect to MCC loading to study its potential application as ocular inserts. The XRD patterns showed a good compatibility between the components. However swelling ratio and in-vitro degradation of EVA increase with MCC loading. This has been explained in terms of the hygroscopic nature of cellulose acetate. The study shows that EVA/MCC system can be tuned in terms of important parameters such as swelling behavior, in vitro release and degradation by varying blend composition, thus fulfilling specific biomedical requirements.

  11. 隐晶质石墨浮选的试验研究%Experimental Research on Flotation of Microcrystalline Graphite

    Institute of Scientific and Technical Information of China (English)

    吴柏君; 张国范; 欧乐明; 梁晓

    2015-01-01

    对湖南鲁塘地区隐晶质石墨进行选矿试验研究,确定了最佳的粗选条件,在此基础上,通过1粗3精的开路试验得到固定碳含量为85%和75%以上的两种产品,产品综合回收率为87.65%。%A beneficiation test of microcrystalline graphite ore from Lutang in Hunan was studied, the optimum roughing conditions are determined. On this basis, ifnally through lfotation process of one roughing-three cleanings get two products of ifxed carbon more than 85% and 75%, comprehensive recovery of products is 87.65%.

  12. High rate deposition of microcrystalline silicon films by high-pressure radio frequency plasma enhanced chemical vapor deposition (PECVD)

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Hydrogenated microcrystalline silicon (μc-Si:H) thin films were prepared by high- pressure radio-frequency (13.56 MHz) plasma enhanced chemical vapor deposition (rf-PECVD) with a screened plasma. The deposition rate and crystallinity varying with the deposition pressure, rf power, hydrogen dilution ratio and electrodes distance were systematically studied. By optimizing the deposition parameters the device quality μc-Si:H films have been achieved with a high deposition rate of 7.8 /s at a high pressure. The Voc of 560 mV and the FF of 0.70 have been achieved for a single-junction μc-Si:H p-i-n solar cell at a deposition rate of 7.8 /s.

  13. The study of the substrate temperature depended growth properties of microcrystalline silicon films deposited by VHF-PECVD method

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yongsheng, E-mail: chysh2003@zzu.edu.cn [Key Lab of Material Physics, Department of Physics, Zhengzhou University, Zhengzhou 450052 (China); Chen, Xiping; Hao, Xiuli; Lu, Jingxiao; Yang, Shi-e [Key Lab of Material Physics, Department of Physics, Zhengzhou University, Zhengzhou 450052 (China)

    2013-04-01

    In this paper, we have measured the temperature depended growth properties of hydrogenated microcrystalline silicon (μc-Si:H) films, prepared by very high frequency plasma-enhanced chemical vapor deposition (VHF-PECVD) from SiH{sub 4} and H{sub 2} gas mixtures. And, a 1D plasma model coupled with a well-mixed reactor model is used to simulate the growth process, in which concentrations of gas phase species, the crystalline orientation, the hydrogen content and the deposition rate are calculated. It suggests that the increasing surface fraction of the dangling bonds with the increase of substrate temperatures is responsible for the increase in the grain sizes. At the same time, the observed variations of the X-ray-diffraction intensities and the deposition rates of the films with temperature result from the differences in the growth rates of the facets.

  14. Exploration of melt granulation technique for the development of coprocessed directly compressible adjuvant containing lactose and microcrystalline cellulose.

    Science.gov (United States)

    Gohe, Mukesh C; Jogani, Pranav D

    2003-01-01

    The objective of the present investigation was to prepare and evaluate lactose and microcrystalline cellulose based, directly compressible adjuvant using melt granulation technique. The percentage of polymer blend (PVP K 30 and PEG 4000; 5, 10, or 15%) and the polymer blend ratio (9:1, 1:1, or 1:9) were selected as independent variables in a 3(2) full factorial design. The lactose and microcrystalline cellulose blend (3:1) was mixed with the meltable binder on a water bath at 90 degrees C. The agglomerates were cooled to 35 degrees C and subsequently passed through 30 mesh. A batch containing 12.5% of the polymer blend containing 1:9 ratio of PVP:PEG was used for further studies. In an another 3(2) full factorial design, disintegrant (crospovidone, croscarmellose sodium, or sodium starch glycolate) and mode of addition of disintegrant (intragranular, extragranular, or combination of intragranular and extragranular) were used as independent variables. The agglomerates were evaluated for percentage fines and Carr's index. Tablets were prepared on a single-punch tablet machine, and they were evaluated for tensile strength, friability, and disintegration time. Regression analysis was carried out to evolve full and refined models. Contour plots are presented for graphical expression of the results. The use of composite index is demonstrated for the selection of an appropriate batch. The disintegration time of tablets reduced from 18 min to 6 min when 6% crospovidone was included in the product. The optimized adjuvant was characterized for particle size distribution, granular friability, Kawakita's and Kuno's equation, and dilution potential study. Turmeric, glycyrrhiza, acetaminophen, and metformin HCl were used as model drugs for the preparation of tablets. The present study underlines the fact that melt granulation technique may be adopted for the development of multifunctional directly compressible adjuvant for use in pharmaceuticals. The advantages of melt

  15. Development of Tandem Amorphous/Microcrystalline Silicon Thin-Film Large-Area See-Through Color Solar Panels with Reflective Layer and 4-Step Laser Scribing for Building-Integrated Photovoltaic Applications

    National Research Council Canada - National Science Library

    Tsai, Chin-Yi; Tsai, Chin-Yao

    2014-01-01

      In this work, tandem amorphous/microcrystalline silicon thin-film large-area see-through color solar modules were successfully designed and developed for building-integrated photovoltaic applications...

  16. SYNTHESIS AND CHARACTERIZATION OF THE LAMELLAR MICROCRYSTALLINE ZINC PHOSPHATE α-Zn3 (PO4)2·4H2O

    Institute of Scientific and Technical Information of China (English)

    Yuan Aiqun; Bai Lijuan; Ma Shaomei; Tong Zhangfa

    2006-01-01

    Objective To study the structural and anticorrosive property of microcrystalline α-Zn3 (PO4)2 ·4H2O. Methods Zinc phosphate was prepared from zinc acetate and orthophosphate acid in aqueous solution.Structural characteristics of products were investigated by XRD, RAMAN, FTIR, TG-DTA, SEM, surface area,particle size distribution, and density measurements. Results The title compound, a highly crystalline, micronized (A), c0 =5. 0304(A), V=975.86 (A)3. Its specific area is 0. 701 m2/g, density 3. 1612 g/m3 , and average size 4.75μm . Conclusion Comparing with commercial Zinc phosphate, the synthesized iamellar microcrystalline zinc phosphate had excellent anticorrosive property and dispersibility.

  17. The composition and structure of macro and microcrystalline paraffin waxes. Part 2. Results of analysis; Ueber die Zusammensetzung von makro- und mikrokristallinen Paraffinen. Teil 2. Untersuchungsergebnisse

    Energy Technology Data Exchange (ETDEWEB)

    Matthaei, M.; Butz, T. [Sasol Wax GmbH, Hamburg (Germany); Geissler, A. [Hochschule Zittau/Goerlitz (Germany)

    2004-02-01

    The composition and structure of the non-n-alkane fraction of macrocrystalline and microcrystalline paraffin waxes are described inconsistently and with contradictions in the current literature. Therefore, the aim of this work was to evaluate the substance of previous analytical techniques, in order to further develop and improve these methods and to state more precisely and thus broaden the knowledge of the structure of petroleum paraffin waxes. IR structure group analysis only resulted in relatively imprecise information. GC-MS enabled the identification and semi quantitative determination of various cycloalkanes. By adopting and further developing a polymer analysis {sup 13}C-NMR structure group analysis method it was possible to identify and to determine the semiquantification of 20 different structure groups. From the results we concluded that the non-n-alkane fraction of paraffin waxes mainly consists of isoalkanes. The side-chains of the isoalkanes are mainly located at the {gamma} position and consist to 60-80% of methyl groups, 5-20% of ethyl groups and 15-20% of longer alkyl groups. An average macrocrystalline paraffin molecule has about 0.14 side chains, an average microcrystalline paraffin molecule up to 0.67 side chains. Regarding the naphthenic structure class, only mono- and dialkyl substitued cyclohexanes were found with alkyl chain lengths of up to C{sub 26} in macrocrystalline paraffin and up to C{sub 34} in microcrystalline paraffin. The number of cyclohexyl groups in the average molecule increases with the graduation of the paraffin wax and reaches up to 0.22 maximum in microcrystalline wax. (orig.)

  18. Bioaugmented hydrogen production from microcrystalline cellulose using co-culture - Clostridium acetobutylicumX{sub 9} and Ethanoigenens harbinenseB{sub 49}

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Aijie; Ren, Nanqi; Shi, Yinguen [School of Municipal and Environmental Engineering, Harbin Institute of Technology, P.O. Box 2614, 202 Haihe Road, Harbin 150090 (China); Lee, Duu-Jong [School of Municipal and Environmental Engineering, Harbin Institute of Technology, P.O. Box 2614, 202 Haihe Road, Harbin 150090 (China); Department of Chemical Engineering, National Taiwan University, Taipei (China)

    2008-01-15

    Dark fermentation of microcrystalline cellulose to produce biohydrogen using mono-culture or co-culture of isolated strains was studied. A strain (X{sub 9}) with high hydrogen yield from microcrystalline cellulose was isolated and identified to be closely affiliated with Clostridium acetobutylicum, ATCC 824. At 37{sup o}C and pH 5.0, the mono-culture of X{sub 9} yields hydrogen with a 5-h time lag and end liquid products primarily of acetate and butyrate. The co-culture of X{sub 9} with another strain, Ethanoigenens harbinenseB{sub 49}, which can produce hydrogen efficiently from monosaccharides but directly from microcrystalline cellulose, produced more efficiently the biohydrogen via ethanol-type fermentation metabolism compared with mono-culture X{sub 9} test. Bioaugmentation with X{sub 9}+B{sub 49} improved cellulose hydrolysis and subsequent hydrogen production rates as compared with that of mono-culture bioaugmentation with X{sub 9}. (author)

  19. Mechanical Properties of Microcrystalline Metal-Organic Frameworks (MOFs) Measured by Bimodal Amplitude Modulated-Frequency Modulated Atomic Force Microscopy.

    Science.gov (United States)

    Sun, Yao; Hu, Zhigang; Zhao, Dan; Zeng, Kaiyang

    2017-09-08

    Direct measurement of the mechanical properties of microcrystalline metal-organic framework (MOF) nanoparticles is challenging and rarely explored. In this work, we apply an effective method to realize elastic modulus mapping of a series of isostructural single MOF nanoparticles (100-500 nm) via bimodal amplitude modulated-frequency modulated atomic force microscopy. By probing five types of zirconium (Zr) and hafnium (Hf) isostructural UiO-66-type MOFs, we experimentally found that UiO-66(Hf)-type MOFs possess the higher elastic modulus (46-104 GPa) than that of UiO-66(Zr)-type MOFs (34-100 GPa), both of which are higher than that of reported zinc/copper based MOFs (3-10 GPa). We also experimentally demonstrate that the mechanical properties of MOFs can be tuned by adjusting the chemical functionalities of the ligands or using different metal nodes. In detail, the sterically bulky functional groups increase the mechanical properties of the resultant UiO-66-type MOFs, possibly due to the increased atomic density. These results pave a way to the direct measurement of mechanical properties of MOFs crystalline particles and provide an incisive perspective to the design of MOFs with high mechanical properties.

  20. Chitosan-kaolin coprecipitate as disintegrant in microcrystalline cellulose-based pellets elaborated by extrusion-spheronization.

    Science.gov (United States)

    Goyanes, Alvaro; Souto, Consuelo; Martínez-Pacheco, Ramón

    2013-02-01

    The usefulness of a coprecipitate of chitosan and kaolin as disintegrant in the pellets of microcrystalline cellulose (MCC) and hydrochlorothiazide (HCT) (as a model of poorly water-soluble drug) produced by extrusion-spheronization was evaluated in this study. The effectiveness of chitosan-kaolin coprecipitate to increase the dissolution rate was compared with that of kaolin and chitosan. A possible synergy effect was also evaluated between the coprecipitate, kaolin or chitosan and sorbitol, added to the pellets as a very water-soluble diluent. The chitosan-kaolin coprecipitate, the kaolin or the chitosan allowed pellets to be obtained of adequate size, roundness, mechanical strength and flow properties. Furthermore, the incorporation of chitosan-kaolin coprecipitate or chitosan significantly increased the dissolution rate of HCT independently of the sorbitol content. The effects on the dissolution of HCT derived from the incorporation of coprecipitate to the pellets can be attributed to its content of chitosan. However, the addition of kaolin into the pellets did not significantly affect the HCT dissolution process. The pellets incorporating coprecipitated chitosan-kaolin or chitosan and the maximum proportion of sorbitol (50%) led to the highest HCT dissolution rate and experienced a rapid and complete disintegration in the dissolution medium.

  1. Exploring the potential of polacrilin potassium as a novel superdisintegrant in microcrystalline cellulose based pellets prepared by extrusion-spheronization

    Directory of Open Access Journals (Sweden)

    Amita K Joshi

    2011-01-01

    Full Text Available Polacrilin potassium (PP, an ion exchange resin, was used as a superdisintegrant to improve the dissolution of rifampicin, from microcrystalline cellulose (MCC based pellets prepared by extrusion-spheronization. Production of fast release pellets by extrusion-spheronization using MCC is a complicated process. In the present study, pellets were prepared containing 50% w/w rifampicin (BCS class II drug and 40% w/w MCC as extrusion-spheronization aid. Different levels of PP and lactose ratio investigated were 0:10, 2:8, 4:6, 6:4, 8:2, and 10:0. Pellets were evaluated for yield, size, size distribution, shape, porosity, friability, residual moisture, and dissolution efficiency (DE at 30 minutes. Incorporation of this novel superdisintegrant had no adverse effect on the mechanical and micromeritic characteristics of pellets. All the batches of pellets showed high yields′, ~90%; narrow particle size distribution; aspect ratio, 1.0-1.1; friability, <1%; and porosity, 45.51-49.84%. Dissolution profiles were compared using model-independent approaches; DE and similarity factor, f 2 . Addition of Polacrilin results in significant improvement in the DE of rifampicin. The dissolution profiles were significantly different from the dissolution profile of pellets formulated without PP. This preliminary study indicates that PP can serve as an effective superdisintegrant in MCC pellets prepared by extrusion-spheronization.

  2. Statistical Optimization for Acid Hydrolysis of Microcrystalline Cellulose and Its Physiochemical Characterization by Using Metal Ion Catalyst

    Directory of Open Access Journals (Sweden)

    Md. Ziaul Karim

    2014-10-01

    Full Text Available Hydrolyzing the amorphous region while keeping the crystalline region unaltered is the key technology for producing nanocellulose. This study investigated if the dissolution properties of the amorphous region of microcrystalline cellulose can be enhanced in the presence of Fe3+ salt in acidic medium. The process parameters, including temperature, time and the concentration of metal chloride catalyst (FeCl3, were optimized by using the response surface methodology (RSM. The experimental observation demonstrated that temperature and time play vital roles in hydrolyzing the amorphous sections of cellulose. This would yield hydrocellulose with higher crystallinity. The factors that were varied for the production of hydrocellulose were the temperature (x1, time (x2 and FeCl3 catalyst concentration (x3. Responses were measured in terms of percentage of crystallinity (y1 and the yield (y2 of the prepared hydrocellulose. Relevant mathematical models were developed. Analysis of variance (ANOVA was carried out to obtain the most significant factors influencing the responses of the percentage of crystallinity and yield. Under optimum conditions, the percentage of crystallinity and yield were 83.46% and 86.98% respectively, at 90.95 °C, 6 h, with a catalyst concentration of 1 M. The physiochemical characteristics of the prepared hydrocellulose were determined in terms of XRD, SEM, TGA and FTIR analyses. The addition of FeCl3 salt in acid hydrolyzing medium is a novel technique for substantially increasing crystallinity with a significant morphological change.

  3. Joint action of ultrasonic and Fe³⁺ to improve selectivity of acid hydrolysis for microcrystalline cellulose.

    Science.gov (United States)

    Li, Jinbao; Qiang, Dandan; Zhang, Meiyun; Xiu, Huijuan; Zhang, Xiangrong

    2015-09-20

    In this study, the combination of Fe(3+)/HCl and ultrasonic treatment was applied to selectively hydrolyze cellulose for the preparation of microcrystalline cellulose (MCC). It was found that the crystallinity and specific surface area of hydrocellulose samples were higher (78.92% and 2.23581 m(2)g(-1), respectively), compared with the method that only used Fe(3+)/HCl catalyst without ultrasonic treatment. Meanwhile, the hydrolysate can be extracted and reused for cellulose hydrolysis for three runs, which was effective in saving the dosage of chemicals and reducing the pollution of the environment without affecting the properties of hydrocellulose. Moreover, the increased concentration of total reducing sugar (TRS) after three runs may be used as a valuable source in biofuels production. The technology of cellulose hydrolysis, by retaining the crystalline region for MCC products while promoting hydrolysis of amorphous region for further utilization is of great novelty, which may prove valuable in converting biomass into chemicals and biofuels, environmentally and economically. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. A novel process for synthesis of spherical nanocellulose by controlled hydrolysis of microcrystalline cellulose using anaerobic microbial consortium.

    Science.gov (United States)

    Satyamurthy, P; Vigneshwaran, N

    2013-01-10

    Degradation of cellulose by anaerobic microbial consortium is brought about either by an exocellular process or by secretion of extracellular enzymes. In this work, a novel route for synthesis of nanocellulose is described where in an anaerobic microbial consortium enriched for cellulase producers is used for hydrolysis. Microcrystalline cellulose derived from cotton fibers was subjected to controlled hydrolysis by the anaerobic microbial consortium and the resultant nanocellulose was purified by differential centrifugation technique. The nanocellulose had a bimodal size distribution (43±13 and 119±9 nm) as revealed by atomic force microscopy. A maximum nanocellulose yield of 12.3% was achieved in a span of 7 days. While the conventional process of nanocellulose preparation using 63.5% (w/w) sulfuric acid resulted in the formation of whisker shaped nanocellulose with surface modified by sulfation, controlled hydrolysis by anaerobic microbial consortium yielded spherical nanocellulose also referred to as nano crystalline cellulose (NCC) without any surface modification as evidenced from Fourier transform infrared spectroscopy. Also, it scores over chemo-mechanical production of nanofibrillated cellulose by consuming less energy due to enzyme (cellulase) assisted catalysis. This implies the scope for use of microbial prepared nanocellulose in drug delivery and bio-medical applications requiring bio-compatibility. Copyright © 2012 Elsevier Inc. All rights reserved.

  5. Physicochemical properties and characteristics of microcrystalline cellulose derived from the cellulose of oil palm empty fruit bunch

    Science.gov (United States)

    Nasution, H.; Yurnaliza; Veronicha; Irmadani; Sitompul, S.

    2017-07-01

    Cellulose from oil palm empty fruit bunch was hydrolyzed with different concentration of hydrochloric acid (HCl) viz. 2; 2.5; 3; 3.5 N to prepare microcrystalline cellulose (MCC). The temperature of hydrolysis process was at 75 °C. The physicochemical properties such as organoleptic characteristic, water soluble substance, and loss on drying were conducted during this study. Infrared, x-ray diffraction, and scanning electron microscope (SEM) image were also performed to investigate the effect of hydrolysis on the molecular structure, crystal structure and morphology of the MCC, respectively. The results have showed, in term of the physicochemical properties, for all concentrations of HCl the MCC was obtained. The FTIR results showed the -OH functional group tended to reduced as alpha cellulose has changed to MCC. The x-ray diffraction pattern revealed that the crystal structure was traced on MCC where the highest was observed at hydrolysis process of 2.5N HCl. The image from SEM displayed an individualized and fibrous MCC on the treatment of 2.5N HCl.

  6. Role of oxygen and nitrogen in n-type microcrystalline silicon carbide grown by hot wire chemical vapor deposition

    Science.gov (United States)

    Pomaska, Manuel; Mock, Jan; Köhler, Florian; Zastrow, Uwe; Perani, Martina; Astakhov, Oleksandr; Cavalcoli, Daniela; Carius, Reinhard; Finger, Friedhelm; Ding, Kaining

    2016-12-01

    N-type microcrystalline silicon carbide (μc-SiC:H(n)) deposited by hot wire chemical vapor deposition provides advantageous opto-electronic properties for window layer material in silicon-based thin-film solar cells and silicon heterojunction solar cells. So far, it is known that the dark conductivity (σd) increases with the increase in the crystallinity of μc-SiC:H(n)films. However, due to the fact that no active doping source is used, the mechanism of electrical transport in these films is still under debate. It is suggested that unintentional doping by atmospheric oxygen (O) or nitrogen (N) contamination plays an important role in the electrical transport. To investigate the impact of O and N, we incorporated O and N in μc-SiC:H(n) films and compared the influence on the microstructural, electronic, and optical properties. We discovered that, in addition to increasing the crystallinity, it is also possible to increase the σd by several orders of magnitude by increasing the O-concentration or the N-concentration in the films. Combining a high concentration of O and N, along with a high crystallinity in the film, we optimized the σd to a maximum of 5 S/cm.

  7. Identification of hydroxyl protons, determination of their exchange dynamics, and characterization of hydrogen bonding in a microcrystallin protein.

    Science.gov (United States)

    Agarwal, Vipin; Linser, Rasmus; Fink, Uwe; Faelber, Katja; Reif, Bernd

    2010-03-10

    Heteronuclear correlation experiments employing perdeuterated proteins enable the observation of all hydroxyl protons in a microcrystalline protein by MAS solid-state NMR. Dipolar-based sequences allow magnetization transfers that are >50 times faster compared to scalar-coupling-based sequences, which significantly facilitates their assignment. Hydroxyl exchange rates were measured using EXSY-type experiments. We find a biexponential decay behavior for those hydroxyl groups that are involved in side chain-side chain C-O-H...O horizontal lineC hydrogen bonds. The quantification of the distances between the hydroxyl proton and the carbon atoms in the hydrogen-bonding donor as well as acceptor group is achieved via a REDOR experiment. In combination with X-ray data and isotropic proton chemical shifts, availability of (1)H,(13)C distance information can aid in the quantitative description of the geometry of these hydrogen bonds. Similarly, correlations between backbone amide proton and carbonyl atoms are observed, which will be useful in the analysis of the registry of beta-strand arrangement in amyloid fibrils.

  8. Simple and selective spectrophotometric determination of ruthenium after solid phase extraction with some quinoxaline dyes into microcrystalline p-dichlorobenzene

    Science.gov (United States)

    Amin, Alaa S.

    2002-07-01

    A simple selective and highly sensitive extraction method has been developed for the determination of ruthenium spectrophotometrically after extraction of its 2,3-dichloro-6-(3-carboxy-2-hydroxy-1-naphthylazo)quinoxaline (I), 2,3-dichloro-6-(2-hydroxy-3,5-dinitrophenylazo)quinoxaline (II) and 2,3-dichloro-6-(2,7-dihydroxy-naphthylazo)quinoxaline (III) complexes into microcrystalline p-dichlorobenzene. The optimization of experimental conditions for the procedure is studied. The solid p-dichlorobenzene containing the ruthenium-reagent (I-III) complexes is separated by filtration and dissolved in N, N-dimethylformamide. The absorbance is measured at λmax 622, 518 and 542 nm against reagents I, II and III, respectively, as blank. Beer's law is obeyed upto 2.5 μg ml -1 of ruthenium. The molar absorptivity, Sandell sensitivity, detection and quantification limits are calculated, when compared with those parameters without using solid phase extraction method. The interference of various ions has been studied in detail and the statistical evaluation of the experimental results is reported. The proposed methods have been successfully applied for the determination of trace amount of ruthenium in seawater, ore and metallurgy products.

  9. Functionalization of Microcrystalline Cellulose with N,N-dimethyldodecylamine for the Removal of Congo Red Dye from an Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Dongying Hu

    2014-08-01

    Full Text Available Microcrystalline cellulose (MCC was functionalized with quaternary amine groups for use as an adsorbent to remove Congo Red dye (CR from aqueous solution. The ultrasonic pretreatment of MCC was investigated during its functionalization. Characterization was conducted using infrared spectroscopy (FT-IR, X-ray photoelectron spectroscopy (XPS, X-ray diffraction (XRD, and scanning electron microscopy (SEM. The batch adsorption of the functionalized MCC was studied to evaluate the effects of dye concentration, pH of solution, temperature, and NaCl concentration on the adsorption CR. The adsorbent (FM-1 obtained using ultrasonic pretreatment of MCC under 10.8 kJ•g–1 exhibited an adsorption capacity of 304 mg•g–1 at initial pH under a dose of 0.1 g•L–1 and initial concentration of 80 mg•L–1. After functionalization, the FT-IR and XPS results indicated that the quaternary amine group was successfully grafted onto the cellulose, the surface was transformed to be coarse and porous, and the crystalline structure of the original cellulose was disrupted. FM-1 has been shown to be a promising and efficient adsorbent for the removal of CR from an aqueous solution.

  10. Rapid thermal annealing of sputter-deposited ZnO:Al films for microcrystalline Si thin-film solar cells

    Directory of Open Access Journals (Sweden)

    Hanajiri T.

    2012-06-01

    Full Text Available Rapid thermal annealing of sputter-deposited ZnO and Al-doped ZnO (AZO films with and without an amorphous silicon (a-Si capping layer was investigated using a radio-frequency (rf argon thermal plasma jet of argon at atmospheric pressure. The resistivity of bare ZnO films on glass decreased from 108 to 104–105 Ω cm at maximum surface temperatures Tmaxs above 650 °C, whereas the resistivity increased from 10-4 to 10-3–10-2Ω cm for bare AZO films. On the other hand, the resistivity of AZO films with a 30-nm-thick a-Si capping layer remained below 10-4Ω cm, even after TPJ annealing at a Tmax of 825 °C. The film crystallization of both AZO and a-Si layers was promoted without the formation of an intermixing layer. Additionally, the crystallization of phosphorous- and boron-doped a-Si layers at the sample surface was promoted, compared to that of intrinsic a-Si under the identical plasma annealing conditions. The TPJ annealing of n+-a-Si/textured AZO was applied for single junction n-i-p microcrystalline Si thin-film solar cells.

  11. Arrays of ZnO nanocolumns for 3-dimensional very thin amorphous and microcrystalline silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Neykova, Neda, E-mail: neykova@fzu.cz [Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, 16253 Prague 6 (Czech Republic); Czech Technical University in Prague, Faculty of Nuclear Sciences and Physical Engineering Trojanova 13, 120 00 Prague 2 (Czech Republic); Hruska, Karel; Holovsky, Jakub; Remes, Zdenek; Vanecek, Milan [Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, 16253 Prague 6 (Czech Republic)

    2013-09-30

    We report on the hydrothermal growth of high quality arrays of single crystalline zinc oxide (ZnO) nanocolumns, oriented perpendicularly to the transparent conductive oxide substrate. In order to obtain precisely defined spacing and arrangement of ZnO nanocolumns over an area up to 0.5 cm{sup 2}, we used electron beam lithography. Vertically aligned ZnO (multicrystalline or single crystals) nanocolumns were grown in an aqueous solution of zinc nitrate hexahydrate and hexamethylenetetramine at 95 °C, with a growth rate 0.5 ÷ 1 μm/h. The morphology of the nanostructures was visualized by scanning electron microscopy. Such nanostructured ZnO films were used as a substrate for the recently developed 3-dimensional thin film silicon (amorphous, microcrystalline) solar cell, with a high efficiency potential. The photoelectrical and optical properties of the ZnO nanocolumns and the silicon absorber layers of these type nanostructured solar cells were investigated in details. - Highlights: • Vertically-oriented ZnO nanocolumns were grown by hydrothermal method. • The ZnO nanocolumns were grown over an area of 0.5 cm{sup 2}. • For precise arrangement of the ZnO nanocolumns electron beam lithography was used. • We report on 3-D design of nanostructured solar cell. • Optical thickness of nanostructured cell was three times higher compared to flat cell.

  12. Collaborative form(s)

    DEFF Research Database (Denmark)

    Gunn, Wendy

    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...

  13. Structure and backbone dynamics of a microcrystalline metalloprotein by solid-state NMR.

    Science.gov (United States)

    Knight, Michael J; Pell, Andrew J; Bertini, Ivano; Felli, Isabella C; Gonnelli, Leonardo; Pierattelli, Roberta; Herrmann, Torsten; Emsley, Lyndon; Pintacuda, Guido

    2012-07-10

    We introduce a new approach to improve structural and dynamical determination of large metalloproteins using solid-state nuclear magnetic resonance (NMR) with (1)H detection under ultrafast magic angle spinning (MAS). The approach is based on the rapid and sensitive acquisition of an extensive set of (15)N and (13)C nuclear relaxation rates. The system on which we demonstrate these methods is the enzyme Cu, Zn superoxide dismutase (SOD), which coordinates a Cu ion available either in Cu(+) (diamagnetic) or Cu(2+) (paramagnetic) form. Paramagnetic relaxation enhancements are obtained from the difference in rates measured in the two forms and are employed as structural constraints for the determination of the protein structure. When added to (1)H-(1)H distance restraints, they are shown to yield a twofold improvement of the precision of the structure. Site-specific order parameters and timescales of motion are obtained by a gaussian axial fluctuation (GAF) analysis of the relaxation rates of the diamagnetic molecule, and interpreted in relation to backbone structure and metal binding. Timescales for motion are found to be in the range of the overall correlation time in solution, where internal motions characterized here would not be observable.

  14. Biocatalytic methanolysis activities of cross-linked protein-coated microcrystalline lipase toward esterification/transesterification of relevant palm products.

    Science.gov (United States)

    Raita, Marisa; Laosiripojana, Navadol; Champreda, Verawat

    2015-03-01

    Biocatalysis by immobilized lipase is an efficient alternative process for conversion of crude vegetable oil with high free fatty acid content to biodiesel, which is the limit of the conventional alkaline-catalyzed reaction. In this study, influences of solid-state organic and inorganic buffer core matrices with different pKa on catalytic performance of cross-linked protein coated microcrystalline biocatalysts prepared from Thermomyces lanuginosus lipase (CL-PCMC-LIP) toward esterification of palmitic acid (PA), transesterification of refined palm oil (RPO), and co-ester/transesterification of crude palm oil (CPO) to fatty acid methyl ester (FAME) was studied. Glycine, CAPSO (3-(cyclohexylamino)-2-hydroxy-1-propanesulfonic acid), and TAPS ([(2-hydroxy-1,1-bis(hydroxymethyl)ethyl)amino]-1-propanesulfonic acid) were shown to be potent core matrices for these reactions. The optimal reaction contained 4:1 [methanol]/[fatty acid] molar equivalence ratio with 20% (w/w) CL-PCMC-LIP on glycine in the presence of tert-butanol as a co-solvent. Deactivation effect of glycerol on the biocatalyst reactive surface was shown by FTIR, which could be alleviated by increasing co-solvent content. The maximal FAME yields from PA, RPO, and CPO reached 97.6, 94.9, and 95.5%, respectively on a molar basis under the optimum conditions after incubation at 50°C for 6h. The biocatalyst retained >80% activity after recycling in five consecutive batches. The work demonstrates the potential of CL-PCMC-LIP on one-step conversion of inexpensive crude fatty acid-rich feedstock to biodiesel. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Enhancing the plasma illumination behaviour of microplasma devices using microcrystalline/ultra-nanocrystalline hybrid diamond materials as cathodes.

    Science.gov (United States)

    Chang, Tinghsun; Lou, Shiucheng; Chen, Huangchin; Chen, Chulung; Lee, Chiyoung; Tai, Nyanhwa; Lin, Inan

    2013-08-21

    The properties of capacity-type microplasma devices were significantly enhanced due to the utilisation of hybrid diamond films as cathodes. The performance of the microplasma devices was closely correlated with the electron field emission (EFE) properties of the diamond cathode materials. The nanoemitters, which were prepared by growing duplex-structured diamond films [microcrystalline diamond (MCD)/ultra-nanocrystalline diamond (UNCD)] on Si-pyramid templates via a two-step microwave plasma enhanced chemical vapour deposition (MPE-CVD) process, exhibited improved EFE properties (E0 = 5.99 V μm(-1), J(e) = 1.10 mA cm(-2) at 8.50 V μm(-1) applied field), resulting in superior microplasma device performance (with a lower threshold field of 200 V mm(-1) and a higher plasma current density of 7.80 mA cm(-2)) in comparison with UNCD film devices prepared using a single-step MPE-CVD process. The superior EFE properties of the duplex-structured MCD-UNCD films relative to those of the UNCD films can be attributed to the unique granular structure of the diamond films. High-resolution transmission electron microscopy reveals that the MCD-UNCD films consisted of abundant graphitic phases located at the periphery of large diamond aggregates and at the boundaries between the ultra-small diamond grains. The presence of the graphite phase is presumed to be the prime factor that renders these films more conductive and causes these films to exhibit higher EFE properties, thus resulting in the improved plasma illumination properties of the microplasma devices.

  16. Impact of microcrystalline silicon carbide growth using hot-wire chemical vapor deposition on crystalline silicon surface passivation

    Energy Technology Data Exchange (ETDEWEB)

    Pomaska, M., E-mail: m.pomaksa@fz-juelich.de [Forschungszentrum Jülich, IEK5-Photovoltaics, Wilhelm-Johnen-Strasse, 52425 Jülich (Germany); Beyer, W. [Helmholtz-Zentrum Berlin für Materialien und Energie, Silicon Photovoltaics, Kekuléstrasse 5, 12489 Berlin (Germany); Neumann, E. [Forschungszentrum Jülich, PGI-8-PT, Wilhelm-Johnen-Strasse, 52425 Jülich (Germany); Finger, F.; Ding, K. [Forschungszentrum Jülich, IEK5-Photovoltaics, Wilhelm-Johnen-Strasse, 52425 Jülich (Germany)

    2015-11-30

    Highly crystalline microcrystalline silicon carbide (μc-SiC:H) with excellent optoelectronic material properties is a promising candidate as highly transparent doped layer in silicon heterojunction (SHJ) solar cells. These high quality materials are usually produced using hot wire chemical vapor deposition under aggressive growth conditions giving rise to the removal of the underlying passivation layer and thus the deterioration of the crystalline silicon (c-Si) surface passivation. In this work, we introduced the n-type μc-SiC:H/n-type μc-SiO{sub x}:H/intrinsic a-SiO{sub x}:H stack as a front layer configuration for p-type SHJ solar cells with the μc-SiO{sub x}:H layer acting as an etch-resistant layer against the reactive deposition conditions during the μc-SiC:H growth. We observed that the unfavorable expansion of micro-voids at the c-Si interface due to the in-diffusion of hydrogen atoms through the layer stack might be responsible for the deterioration of surface passivation. Excellent lifetime values were achieved under deposition conditions which are needed to grow high quality μc-SiC:H layers for SHJ solar cells. - Highlights: • High surface passivation quality was preserved after μc-SiC:H deposition. • μc-SiC:H/μc-SiO{sub x}:H/a-SiO{sub x}:H stack a promising front layer configuration • Void expansion at a-SiO{sub x}:H/c-Si interface for deteriorated surface passivation • μc-SiC:H provides a high transparency and electrical conductivity.

  17. Dissolution and regeneration of microcrystalline cellulose in 1-ethyl-3-methylimidazolium diethylphosphate%微晶纤维素在EMIM-DEP中的溶解与再生

    Institute of Scientific and Technical Information of China (English)

    陶伟娜; 王少君; 李飞

    2012-01-01

    1-Ethyl-3-methylimidazolium diethylphosphate (EMIM-DEP) is synthesized with microwave method and is used to dissolve microcrystalline cellulose in this study. Its dissolution process is observed by polarizing microscope. With the rise of temperature the solubility of cellulose increases. Ultrasonic auxiliary can improve well the solubility of microcrystalline cellulose in ionic liquids. The regenerated cellulose is characterized by FT-IR, XRD, SEM and TGA. The results show that the microcrystalline cellulose in EMIM-DEP is dissolved directly without derivative reaction. The regenerated cellulose is changed from cellulose I into cellulose II in crystal style. Recovered ionic liquid has no change in structure and can be reused with good dissolving ability for microcrystalline cellulose.%通过微波法合成1-乙基-3-甲基咪唑磷酸二乙酯离子液体(EMIM-DEP)并用其溶解微晶纤维素.用偏光显微镜观察微晶纤维素在离子液体中的溶解.随温度的升高纤维素的溶解度增加,超声辅助可以很好地提高微晶纤维素在离子液体中的溶解度.溶解之后再生的纤维素通过红外光谱(FT-IR)、X-射线衍射(XRD)、扫描电镜(SEM)和热重分析(TGA)表征,结果显示微晶纤维素在EMIM-DEP中是直接溶解没有发生衍生反应;再生的纤维素晶型由纤维素Ⅰ型转化为纤维素Ⅱ型;回收后的离子液体结构没发生变化,重复利用仍保持较好的溶解微晶纤维素的能力.

  18. Photo-induced density-of-states variation measured by DLTS method in intrinsic micro-crystalline silicon (i-μc-Si:H) films

    Science.gov (United States)

    Wang, J.; Sun, Q. S.; Liu, H. N.; He, Y. L.

    1987-06-01

    This paper advances a measurement and two calculations of a high-frequency DLTS method for the density-of-states g(E) of intrinsic micro-crystalline and amorphous silicon film. The method surmounts the difficulties of DLTS measurement of i-a-Si:H or i-μc-Si:H samples and applies the common high-frequency DLTS to it, while the temperature of measurement is extended below 77K. Following the method, we successfully observed the obvious increase of density-of-states produced by illumination.

  19. EPR response of sucrose and microcrystalline cellulose to measure high doses of gamma radiation; Respuesta EPR de sacarosa y celulosa micro cristalina para medir altas dosis de radiacion gamma

    Energy Technology Data Exchange (ETDEWEB)

    Torijano, E.; Cruz, L.; Gutierrez, G.; Azorin, J.; Aguirre, F. [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, 09340 Mexico D. F. (Mexico); Cruz Z, E., E-mail: eftc@xanum.uam.mx [UNAM, Instituto de Ciencias Nucleares, Circuito Exterior, Ciudad Universitaria, 04510 Mexico D. F. (Mexico)

    2015-10-15

    Solid dosimeters of sucrose and microcrystalline cellulose (Avicel Ph-102) were prepared, following the same process, in order to compare their EPR response against that of the l-alanine dosimeters considered as reference. All lots of dosimeters were irradiated with gamma radiation in Gamma beam irradiator with 8 kGy/h of the Nuclear Sciences Institute of UNAM. Doses ranged from 1 to 10 kGy respectively. We found that both the response of sucrose as microcrystalline cellulose were linear; however, the response intensity was, on average, twenty times more for sucrose. Comparing this against the EPR response of l-alanine in the range of doses, it was found that the response to sucrose is a third part; and microcrystalline cellulose is a sixtieth, approximately. The results agree with those found in the literature for sucrose, leaving open the possibility of investigating other dosage ranges for cellulose. (Author)

  20. 微晶纤维素在离子液体[Bmim]Cl中的溶解与再生%Dissolution and regeneration of microcrystalline cellulose in ionic liquid [Bmim]Cl

    Institute of Scientific and Technical Information of China (English)

    邹鑫; 杨继涛; 胡国新

    2013-01-01

    利用氯化1-丁基-3-甲基咪唑([Bmim]Cl)溶解微晶纤维素,考察了温度、时间以及[Bmim]Cl与微晶纤维素质量比对微晶纤维素在[Bmim]Cl中的溶解率的影响.研究结果表明,[Bmim]Cl与微晶纤维素质量比为5∶0.5,溶解温度为90℃,溶解时间为1.5 h时,微晶纤维素在[Bmim]Cl中的溶解率最高,为48.7%.同时,借助扫描电镜和X射线衍射仪对再生纤维素的形貌和结晶性进行了分析,结果表明,微晶纤维素在[Bmim]Cl中的溶解属于直接溶解,结晶强度减弱.%1-Butyl-3-methylimidazolium chloride ([Bmim]Cl) was used to dissolve microcrystalline cellulose.Temperature,time and mass ratio of [Bmim]Cl and microcrystalline cellulose which had influence on the dissolving rate of microcrystalline cellulose were investigated.The results showed that the highest dissolving rate of microcrystalline cellulose in [Bmim]Cl achieved 48.7% when the mass ratio of [Bmim]Cl and microcrystalline cellulose was 5:0.5,solution temperature was 90 ℃,lysis time was 1.5 h.The appearance and crystallinity of regenerated cellulose were analyzed by using scanning electron microscope and X-ray diffraction.The results showed that the dissolution of microcrystalline cellulose in [Bmim]Cl was a physical process,and the regenerated cellulose exhibited declining of the crystallization intensity.

  1. Microcrystalline silicon oxides for silicon-based solar cells: impact of the O/Si ratio on the electronic structure

    Science.gov (United States)

    Bär, M.; Starr, D. E.; Lambertz, A.; Holländer, B.; Alsmeier, J.-H.; Weinhardt, L.; Blum, M.; Gorgoi, M.; Yang, W.; Wilks, R. G.; Heske, C.

    2014-10-01

    Hydrogenated microcrystalline silicon oxide (μc-SiOx:H) layers are one alternative approach to ensure sufficient interlayer charge transport while maintaining high transparency and good passivation in Si-based solar cells. We have used a combination of complementary x-ray and electron spectroscopies to study the chemical and electronic structure of the (μc-SiOx:H) material system. With these techniques, we monitor the transition from a purely Si-based crystalline bonding network to a silicon oxide dominated environment, coinciding with a significant decrease of the material's conductivity. Most Si-based solar cell structures contain emitter/contact/passivation layers. Ideally, these layers fulfill their desired task (i.e., induce a sufficiently high internal electric field, ensure a good electric contact, and passivate the interfaces of the absorber) without absorbing light. Usually this leads to a trade-off in which a higher transparency can only be realized at the expense of the layer's ability to properly fulfill its task. One alternative approach is to use hydrogenated microcrystalline silicon oxide (μc-SiOx:H), a mixture of microcrystalline silicon and amorphous silicon (sub)oxide. The crystalline Si regions allow charge transport, while the oxide matrix maintains a high transparency. To date, it is still unclear how in detail the oxygen content influences the electronic structure of the μc-SiOx:H mixed phase material. To address this question, we have studied the chemical and electronic structure of the μc-SiOx:H (0 0.5, we observe a pronounced decrease of Si 3s - Si 3p hybridization in favor of Si 3p - O 2p hybridization in the upper valence band. This coincides with a significant increase of the material's resistivity, possibly indicating the breakdown of the conducting crystalline Si network. Silicon oxide layers with a thickness of several hundred nanometres were deposited in a PECVD (plasma-enhanced chemical vapor deposition) multi chamber system

  2. Investigation of carrier density and mobility in microcrystalline silicon alloys using Hall effect and thermopower measurements; Untersuchung der Ladungstraegerkonzentration und -beweglichkeit in mikrokristallinen Siliziumlegierungen mit Hall-Effekt und Thermokraft

    Energy Technology Data Exchange (ETDEWEB)

    Sellmer, Christian

    2012-08-31

    The electronic properties of amorphous and microcrystalline silicon layers in thin-film solar cells significantly affect the efficiency of solar cells. An important property of the individual layer is the electronic transport, which is described by the variables conductivity, photoconductivity, mobility, and carrier concentration. In the past, individual characterization methods were typically used to determine the electronic properties. Using the combination of Hall effect, conductivity, and thermoelectric power measurements additional variables can be derived, such as the effective density of states at the valence and conduction band edge, making a more detailed description of the material possible. To systematically study the electronic properties - in particular carrier mobility and carrier concentration - various series of silicon films are prepared for this work including microcrystalline silicon layers of different doping and crystallinity and a series of silicon films where the Fermi level is moved by irradiation with high energy electrons on one and the same sample. The results show that the transition from amorphous to microcrystalline transport is relatively abrupt. If the electron transport takes place in only amorphous regions, it is marked by the sign anomaly of the Hall effect. If a continuous crystalline path exists, the electronic properties are dominated by the crystalline volume fraction. The results of the measurements of silicon layers are compared with those of microcrystalline silicon carbide samples. Silicon carbide is especially interesting for future applications in thin-film solar cells due to high transparency and high conductivity. It is shown that the effective density of states at the valence and conduction band edge as a function of temperature in p- and n-type microcrystalline silicon and silicon carbide samples largely coincide with those of crystalline silicon or silicon carbide. A square root shaped profile of the density of

  3. Tailored Voltage Waveform Deposition of Microcrystalline Silicon Thin Films from Hydrogen-Diluted Silane and Silicon Tetrafluoride: Optoelectronic Properties of Films

    Science.gov (United States)

    Johnson, Erik V.; Pouliquen, Sylvain; Delattre, Pierre-Alexandre; Booth, Jean-Paul

    2012-08-01

    The use of tailored voltage waveforms (TVW's) to excite a plasma for the deposition of thin films of hydrogenated microcrystalline silicon (µc-Si:H) has been shown to be an effective technique to decouple mean ion bombardment energy (IBE) from injected power. In this work, we examine the changes in material properties controlled by this technique through Raman scattering and spectroscopic ellipsometry for films deposited from H2-diluted SiH4, and we examine the electrical properties of such films using temperature dependent conductivity. As the laboratory-scale deposition system used had neither a load lock nor an oxygen filter in the H2 line, accidental O-doping was observed for the µc-Si:H films. We investigated suppression of this doping by adding varying amounts of SiF4, and using an SiF4/Ar pre-etch step to clean the reactor. This technique is shown to be effective in decreasing the accidental doping of the films, and intrinsic µc-Si:H films are produced with an activation energy of up to 0.55 eV. As well, an important difference in the amorphous-to-microcrystalline transition is observed once SiF4 is included in the gas mixture.

  4. Performance Improvement of Microcrystalline p-SiC/i-Si/n-Si Thin Film Solar Cells by Using Laser-Assisted Plasma Enhanced Chemical Vapor Deposition

    Directory of Open Access Journals (Sweden)

    Hsin-Ying Lee

    2014-01-01

    Full Text Available The microcrystalline p-SiC/i-Si/n-Si thin film solar cells treated with hydrogen plasma were fabricated at low temperature using a CO2 laser-assisted plasma enhanced chemical vapor deposition (LAPECVD system. According to the micro-Raman results, the i-Si films shifted from 482 cm−1 to 512 cm−1 as the assisting laser power increased from 0 W to 80 W, which indicated a gradual transformation from amorphous to crystalline Si. From X-ray diffraction (XRD results, the microcrystalline i-Si films with (111, (220, and (311 diffraction were obtained. Compared with the Si-based thin film solar cells deposited without laser assistance, the short-circuit current density and the power conversion efficiency of the solar cells with assisting laser power of 80 W were improved from 14.38 mA/cm2 to 18.16 mA/cm2 and from 6.89% to 8.58%, respectively.

  5. Radial n-i-p structure SiNW-based microcrystalline silicon thin-film solar cells on flexible stainless steel.

    Science.gov (United States)

    Xie, Xiaobing; Zeng, Xiangbo; Yang, Ping; Li, Hao; Li, Jingyan; Zhang, Xiaodong; Wang, Qiming

    2012-11-12

    Radial n-i-p structure silicon nanowire (SiNW)-based microcrystalline silicon thin-film solar cells on stainless steel foil was fabricated by plasma-enhanced chemical vapor deposition. The SiNW solar cell displays very low optical reflectance (approximately 15% on average) over a broad range of wavelengths (400 to 1,100 nm). The initial SiNW-based microcrystalline (μc-Si:H) thin-film solar cell has an open-circuit voltage of 0.37 V, short-circuit current density of 13.36 mA/cm2, fill factor of 0.3, and conversion efficiency of 1.48%. After acid treatment, the performance of the modified SiNW-based μc-Si:H thin-film solar cell has been improved remarkably with an open-circuit voltage of 0.48 V, short-circuit current density of 13.42 mA/cm2, fill factor of 0.35, and conversion efficiency of 2.25%. The external quantum efficiency measurements show that the external quantum efficiency response of SiNW solar cells is improved greatly in the wavelength range of 630 to 900 nm compared to the corresponding planar film solar cells.

  6. Influence of low-density polyethylene on the thermal characteristics and crystallinity of high melting point macro- and micro-crystalline waxes

    Energy Technology Data Exchange (ETDEWEB)

    Zaky, Magdy T., E-mail: magdytadrous@hotmail.com [Petroleum Refining Division, Egyptian Petroleum Research Institute (EPRI), 1-Ahmed El-Zomor Street, Hai Al-Zehour, Nasr City, P.O. Box 11727, Cairo (Egypt); Mohamed, Nermen H. [Petroleum Refining Division, Egyptian Petroleum Research Institute (EPRI), 1-Ahmed El-Zomor Street, Hai Al-Zehour, Nasr City, P.O. Box 11727, Cairo (Egypt)

    2010-02-20

    The influence of low-density polyethylene on the thermal characteristics and the crystallinity of high melting point macro- and micro-crystalline waxes were investigated. The samples were prepared through melt blending using mechanical stirrer. The thermal characteristics of the blended samples were determined using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The crystallinity of the samples was obtained using X-ray diffraction analyzer (XRD). The observations are discussed in terms of possible changes when the polymer is mixed with two types of waxes. The wax-polymer miscibility differed with the type of the wax and the amount of polymer mixed into the wax. Also, the crystallinity and congealing point of the waxes differed with the amount of polymer mixed into the wax. Moreover, the resulting data indicate that, blending of polymer with high melting point micro-crystalline wax elevates its melting point to reach the limits of high melting point ceresin waxes which can be used in different industrial applications.

  7. Preparation and Characterisation of Amorphous-silicon Photovoltaic Devices Having Microcrystalline Emitters; Preparacion y Caracterizacion de Dispositivos Fotovoltaicos de Silicio Amorfo con Emisiones Microcristalinos

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez, M. T.; Gandia, J. J.; Carabe, J. [CIEMAT. Madrid (Spain)

    1999-11-01

    The present work summarises the essential aspects of the research carried out so far at CIEMAT on amorphous-silicon solar cells. The experience accumulated on the preparation and characterisation of amorphous and microcrystalline silicon has allowed to start from intrinsic (absorbent) and p-and n-type (emitters) materials not only having excellent optoelectronic properties, but enjoying certain technological advantages with respect to those developed by other groups. Among these are absorbent-layer growth rates between 5 and 10 times as fast as conventional ones and microcrystalline emitters prepared without using hydrogen. The preparation of amorphous-silicon cells has required the solution of a number of problems, such as those related to pinholes, edge leak currents and diffusion of metals into the semiconductor. Once such constraints have been overcome, it has been demonstrated not only that the amorphous-silicon technology developed at CIEMAT is valid for making solar cells, but also that the quality of the semiconductor material is good for the application according to the partial results obtained. The development of thin-film laser-scribing technology is considered essential. Additionally it has been concluded that cross contamination, originated by the fact of using a single-chamber reactor, is the basic factor limiting the quality of the cells developed at CIEMAT. The present research activity is highly focused on the solution of this problem. (Author)

  8. Comparison of γ-irradiation with other pretreatments followed with simultaneous saccharification and fermentation on bioconversion of microcrystalline cellulose for bioethanol production.

    Science.gov (United States)

    Liu, Yun; Zhou, Hua; Wang, Shihui; Wang, Keqin; Su, Xiaojun

    2015-04-01

    The effect of γ-irradiation pretreatment was compared with other pretreatment methods including ionic liquids (ILs), 1% HCl, 1% H2SO4, acidic aqueous Ils (AA-ILs), on the bioconversion efficiency of microcrystalline cellulose (MCC) for bioethanol production. The efficiency of MCC pretreatment followed with simultaneous saccharification and fermentation (SSF) was firstly evaluated according to the variations of the irradiation-derived compounds and structure of MCC, as well as yeast growth curve and bioethanol yield. Results showed that the appropriate irradiation dose (891 kGy used in our work) could eliminate the negative effect of toxic irradiation-derived compounds on SSF for ethanol bioconversion with the yield value of 67%. Analyses of SEM, FT-IR, reducing sugar and bioethanol yield showed that the efficiency of pretreatment on MCC was ILs ≈ irradiation pretreatment > AA-ILs pretreatment > 1% HCl pretreatment > 1% H2SO4 pretreatment.

  9. Use of cellobiohydrolase-free cellulase blends for the hydrolysis of microcrystalline cellulose and sugarcane bagasse pretreated by either ball milling or ionic liquid [Emim][Ac].

    Science.gov (United States)

    Teixeira, Ricardo Sposina Sobral; da Silva, Ayla Sant'Ana; Kim, Han-Woo; Ishikawa, Kazuhiko; Endo, Takashi; Lee, Seung-Hwan; Bon, Elba P S

    2013-12-01

    This study investigated the requirement of cellobiohydrolases (CBH) for saccharification of microcrystalline cellulose and sugarcane bagasse pretreated either by ball milling (BM) or by ionic liquid (IL) [Emim][Ac]. Hydrolysis was done using CBH-free blends of Pyrococcus horikoshii endoglucanase (EG) plus Pyrococcus furiosus β-glucosidase (EGPh/BGPf) or Optimash™ BG while Acremonium Cellulase was used as control. IL-pretreated substrates were hydrolyzed more effectively by CBH-free enzymes than were the BM-pretreated substrates. IL-treatment decreased the crystallinity and increased the specific surface area (SSA), whereas BM-treatment decreased the crystallinity without increasing the SSA. The hydrolysis of IL-treated cellulose by EGPh/BGPf showed a saccharification rate of 3.92 g/Lh and a glucose yield of 81% within 9h. These results indicate the efficiency of CBH-free enzymes for the hydrolysis of IL-treated substrates. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Enhanced Photocatalytic Activity of CdS-Decorated TiO2/Carbon Core-Shell Microspheres Derived from Microcrystalline Cellulose

    Directory of Open Access Journals (Sweden)

    Xin Liu

    2016-03-01

    Full Text Available The fabrication of reusable and biodegradation materials from renewable resources such as cellulose is essential for a sustainable world. The core-shell structured CdS-decorated TiO2/Carbon microspheres (CdS/TiO2/Carbon MS photocatalyst was synthesized with controlled hydrolysis and a novel sonochemical method. It was prepared by using crosslinked microcrystalline cellulose as the core, tetrabutyl titanate as the titania source and CdS as the photosensitizer. The morphology, chemical structure and properties of the obtained material were characterized by many means. Additionally, the photocatalytic activity of the CdS/TiO2/Carbon MS was evaluated by the photodegradation efficiency of Rhodamine B solution, which reached 95.24% under visible light irradiation. This study demonstrated the excellent photocatalytic performance of CdS/TiO2/Carbon MS, which might have promising applications in environmental treatments.

  11. A study of growth mechanism of microcrystalline thin silicon films deposited at low temperature by SiF4{text{-}H2{text{-}}He} PECVD

    Science.gov (United States)

    Losurdo, M.; Giangregorio, M.; Grimaldi, A.; Capezzuto, P.; Bruno, G.

    2004-06-01

    Fully microcrystalline silicon, μc-Si, thin films (polyimide substrates by plasma enhanced chemical vapor deposition (PECVD) using SiF{4}-H{2}-He. The effect of deposition temperature on the structure, i.e., crystallinity and density, of μc-Si films is investigated by spectroscopic ellipsometry in the 1.5 {-}5.5 eV energy range. Modeling of spectroscopic ellipsometry data is used for highlighting crystallinity of the substrate/film interface, i.e., the absence of any amorphous incubation layer. It is found that film crystallinity does not depend on film thickness, and it increases with the decrease of deposition temperature. The temperature dependence is explained on the basis of a like-Arrhenius kinetic analysis of the etching process by atomic fluorine and hydrogen of both μc-Si and a-Si phases.

  12. Preparation of nanocellulose from micro-crystalline cellulose: The effect on the performance and properties of agar-based composite films.

    Science.gov (United States)

    Shankar, Shiv; Rhim, Jong-Whan

    2016-01-01

    A facile approach has been performed to prepare nanocellulose (NC) from micro-crystalline cellulose (MCC) and test their effect on the performance properties of agar-based composite films. The NC was characterized by STEM, XRD, FTIR, and TGA. The NC was well dispersed in distilled water after sonication and their size was in the range of 100-500nm. The XRD results revealed the crystallinity of NC. The crystallinity index of NC (0.71) was decreased compared to the MCC (0.81). The effect of NC or MCC content (1, 3, 5 and 10wt% based on agar) on the mechanical, water vapor permeability (WVP), and thermal properties of the composites were studied. The NC obtained from MCC can be used as a reinforcing agent for the preparation of biodegradable composites films for their potential use in the development of biodegradable food packaging materials.

  13. Optimization of n/i and i/p buffer layers in n-i-p hydrogenated microcrystalline silicon solar cells

    Institute of Scientific and Technical Information of China (English)

    Yuan Yujie; Hou Guofu; Zhang Jianjun; Xue Junming; Cao Liran; Zhao Ying; Geng Xinhua

    2009-01-01

    Hydrogenated microcrystalline silicon (μc-Si:H) intrinsic films and solar cells with n-i-p configuration were prepared by plasma enhanced chemical vapor deposition (PECVD). The influence of n/i and i/p buffer layerson the μc-Si:H cell performance was studied in detail. The experimental results demonstrated that the efficiency is much improved when there is a higher crystallinity at n/i interface and an optimized a-Si:H buffer layer at i/p interface. By combining the above methods, the performance ofμc-Si:H single-junction and a-Si:H/μc-Si:H tandemsolar ceils has been significantly improved.

  14. Surface chemistry of the preferred (111) and (220) crystal oriented microcrystalline Si films by radio-frequency plasma-enhanced chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Ohba, Daisuke; Koshino, Hideto; Tang, Zeguo; Shirai, Hajime [Graduate School of Science and Engineering, Saitama University, Sakura (Japan)

    2011-10-15

    The surface chemistry of the preferentially (111) and (220) crystal orientated chlorinated hydrogenated microcrystalline silicon ({mu}c-Si:H:Cl) films was studied using a rf PE-CVD of a dichlorosilane (SiH{sub 2}Cl{sub 2}) and H{sub 2} mixture. The growing surface for the preferentially (220) crystal oriented {mu}c-Si:H:Cl films included much voids and dangling bonds, whereas the growing surface with the preferential (111) crystal orientation was chemically stable relatively. These findings suggest that the sticking process of deposition precursors and/or the reconstruction of Si clusters within the sub-surface determine the preferential crystal orientation. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. In vitro and in vivo studies on nanocrystalline Ti fabricated by equal channel angular pressing with microcrystalline CP Ti as control.

    Science.gov (United States)

    Nie, F L; Zheng, Y F; Wei, S C; Wang, D S; Yu, Z T; Salimgareeva, G K; Polyakov, A V; Valiev, R Z

    2013-06-01

    Bulk nanocrystalline Ti bars (Grade 4, Φ4 × 3000 mm(3)) were massively fabricated by equal channel angular pressing (ECAP) via follow-up conform scheme with the microcrystalline CP Ti as raw material. Homogeneous nanostructured crystals with the average grain size of 250 nm were identified for the ECAPed Ti, with extremely high tensile/fatigue strength (around 1240/620 MPa) and adorable elongation (more than 5%). Pronounced formation of bonelike apatite for the nanocrystalline Ti group after 14 days static immersion in simulated body fluids (SBF) reveals the prospective in vitro bioactive capability of fast calcification, whereas an estimated 17% increment in protein adsorption represents good bioaffinity of nanocrystalline Ti. The documentation onto the whole life circle of osteoblast cell lines (MG63) revealed the strong interactions and superior cellular functionalization when they are co-incubated with bulk nanocrystalline Ti sample. Moreover, thread-structured specimens were designed and implanted into the tibia of Beagles dogs till 12 weeks to study the in vivo responses between bone and metallic implant made of bulk nanocrystalline Ti, with the microcrystalline Ti as control. For the implanted nanostructured Ti group, neoformed bone around the implants underwent the whole-stage transformation proceeding from originally osteons or immature woven bone to mature lamellar bone (skeletonic trabecular), even with the remodeling being finished till 12 weeks. The phenomenal osseointegration of direct implant-bone contact can be revealed from the group of the ECAPed Ti without fibrous tissue encapsulation in the gap between the implant and autogenous bone.

  16. Synthesis and photoluminescence properties of microcrystalline Sr{sub 2}ZnWO{sub 6}:RE{sup 3+} (RE = Eu, Dy, Sm and Pr) phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Dabre, K.V. [Department of Physics, Arts, Commerce and Science College, Koradi, Nagpur 441111 (India); Park, K. [Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 143-747 (Korea, Republic of); Dhoble, S.J., E-mail: sjdhoble@rediffmail.com [Department of Physics, R.T.M. Nagpur University, Nagpur 440033 (India)

    2014-12-25

    Graphical abstract: CIE chromaticity coordinate diagram (1931) indicating different colors of Sr{sub 2}ZnWO{sub 6}:RE{sup 3+} (RE = Eu (a), Dy (b and c), Sm (d–f) and Pr (g and h)) phosphor under different excitation 466 nm (a), 312 nm (b), 454 nm (c), 313 nm (d), 408 nm (e), 482 nm (f), 315 nm (g) and 450 nm (h). - Highlights: • Microcrystalline Sr{sub 2}ZnWO{sub 6}:RE{sup 3+} (RE = Eu, Dy, Sm and Pr) phosphors were synthesized by solid state method. • Photoluminescence properties of phosphor were investigated. • Color of the phosphor for different excitation has been verified by chromaticity diagram. • The host absorption and energy transfer were investigated. - Abstract: The novel microcrystalline Sr{sub 2}ZnWO{sub 6}:RE{sup 3+} (RE = Eu, Dy, Sm and Pr) phosphors were synthesized by solid-state reaction method at 1250 °C and their photoluminescence properties were investigated. The Eu{sup 3+} and Dy{sup 3+} activated phosphors show intense red (616 nm) and yellow (574 nm) emission respectively; which indicate that the rare earth ions are substituted at non-centrosymmetric site in the host lattice. Near white (Dy{sup 3+}) and reddish-orange (Sm{sup 3+}) emissions of rare earth ions in the host lattice show strong host absorption and energy transfer from the host to activator ion. Pr{sup 3+} activated phosphor shows a series of emission peaks in the visible region with the most intense peak in the blue region at 491 and 499 nm.

  17. Narrative form

    CERN Document Server

    Keen, Suzanne

    2015-01-01

    This revised and expanded handbook concisely introduces narrative form to advanced students of fiction and creative writing, with refreshed references and new discussions of cognitive approaches to narrative, nonfiction, and narrative emotions.

  18. Why is mannitol becoming more and more popular as a pharmaceutical excipient in solid dosage forms?

    Science.gov (United States)

    Ohrem, H Leonhard; Schornick, Eva; Kalivoda, Adela; Ognibene, Roberto

    2014-05-01

    Various fillers/binders which are applied for the formulation of solid oral dosage forms are assessed for their benefits and drawbacks, including lactose, sorbitol, mannitol, microcrystalline cellulose and calcium hydrogen phosphate dihydrate. A focus of this work was to evaluate the application of mannitol in comparison to other common fillers/binders as it was observed that this excipient is gaining more and more attention in pharmaceutical formulation development and production. While one of the main advantages of conventional fillers/binders such as lactose, microcrystalline cellulose and calcium hydrogen phosphate dihydrate is their low price level, mannitol excels regarding its physicochemical characteristics such as a low hygroscopicity, a strong inertness towards both the API and the patient's body, its good compactibility and the ability to produce extremely robust tablets. Additionally, the suitability of mannitol for the emerging formulation technology of orally disintegrating tablets is pointed out. In summary, it is emphasized that the selection of the filler/binder is highly individual, depending, for example, on the preferred characteristics of the final solid dosage form, the applied API and the available budget. However, mannitol exhibits many strong advantages which can be expected to result in a more widespread application in the near future.

  19. STUDY ON MICROCRYSTALLINE SILICON THIN FILM SOLAR CELLS ON FLEXIBLE SUBSTRATE%柔性衬底微晶硅薄膜太阳电池研究

    Institute of Scientific and Technical Information of China (English)

    周丽华; 刘成; 叶晓军; 钱子勍; 陈鸣波

    2011-01-01

    The intrinsic microcrystalline silicon thin film layers (I-layer) and nip single microcrystalline silicon solar cells were prepared by plasma enhanced chemical vapor deposition (PECVD). Then the relationship among deposition parameters, the characteristics of I-layers and the performanceof solar cells was studied. It demonstrated that crystalline fraction of I-layers decreased gradually with the increasing of silicon concentration. And the performance of solar cells deteriorated while the deposition temperature rose over 200℃. With the increasing of discharge power, the crystalline volume fraction maintained the same, but the open circuit voltage of the solar cell and its spectrum response at short wavelength increased gradually. Base on the optimized deposition parameters, single junction solar cells with conversion efficiency of 6.48% (AM0,25℃ ) were fabricated. Finally, tandem solar cells on stainless steel flexible substrate with conversion efficiency of 9. 28% ( AM0,25℃) were obtained.%采用等离子增强化学气相沉积(PECVD)技术制备了系列本征微晶硅薄膜材料和nip单结微晶硅太阳电池,研究了硅烷浓度、衬底温度和辉光功率等沉积参数与薄膜材料性能、薄膜电池性能三者之间的关系.拉曼光谱和器件测试结果表明:随硅烷浓度的增加,本征层晶化率逐渐减小,直至转变为非晶硅;沉积温度高于200℃时,电池性能严重恶化;随等离子辉光功率增加,材料晶化率保持不变,而电池开路电压逐渐增大,短波光谱响应逐渐增强.在此基础上,优化了单结微晶硅电池沉积参数,得到效率为6.48% (AM0,25℃)的单结微晶硅薄膜太阳电池;并将其应用到非晶硅/微晶硅叠层电池中,在不锈钢柔性衬底上得到效率为9.28%( AM0,25℃)的叠层电池.

  20. Fri form

    DEFF Research Database (Denmark)

    Jensen, Henrik

    2006-01-01

    Dette Kompendiun er lavet i forbindelse med en workshop i møbeldesign. En række af form-Z's værktøjer til konstruktion af dobbeltkrumme flader gennemgås. Kompendiet kan bruges til selvstudie.......Dette Kompendiun er lavet i forbindelse med en workshop i møbeldesign. En række af form-Z's værktøjer til konstruktion af dobbeltkrumme flader gennemgås. Kompendiet kan bruges til selvstudie....

  1. Technology Study on Producing High Melting Point Microcrystalline Wax From Shenbei/Daqing Vacuum Residue Oil%沈北/大庆减压渣油生产高熔点微晶蜡工艺研究

    Institute of Scientific and Technical Information of China (English)

    金秀英; 陈白莉; 杜晓敏; 王玉玲; 范燕

    2013-01-01

      沈北/大庆减压渣油中含有丰富的微晶蜡。将渣油亚临界丙烷脱沥青得到轻脱油,再经酮苯脱油-白土精制生产高熔点微晶蜡。说明大庆、沈北混合原油减压渣油经脱沥青等系列工艺处理生产光亮油和微晶蜡的技术可行性,提出了大庆、沈北混合原油减压渣油综合利用的途径。%There is abundant microcrystalline wax in Shenbei/Taqing vacuum residue oil. Light deasphalting oil is often obtained from vacuum residue oil by subcritical propane deasphalting process, then microcrystalline wax with high melting point can be produced by butanone-toluene solvent deoiling and clay-treated refining. In this paper,the technical and economic feasibility of producing bright stock and microcrystalline wax from the vacuum residue of Daqing and Shenbei mixed crude by deasphalting etc.processes was discussed according to the pilot plant test results .Utilization ways of vacuum residue of Daqing and Shenbei mixed crude were put forward.

  2. Automorphic Forms

    DEFF Research Database (Denmark)

    von Essen, Flemming Brændgaard

    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...

  3. 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...

  4. The effect of microcrystalline cellulose crystallinity on the hydrophilic property of tablets and the hydrolysis of acetylsalicylic acid as active pharmaceutical ingredient inside tablets.

    Science.gov (United States)

    Awa, Kimie; Shinzawa, Hideyuki; Ozaki, Yukihiro

    2015-08-01

    The crystal structures of active pharmaceutical ingredients and excipients should be strictly controlled because they influence pharmaceutical properties of products which cause the change in the quality or the bioavailability of the products. In this study, we investigated the effects of microcrystalline cellulose (MCC) crystallinity on the hydrophilic properties of tablets and the hydrolysis of active pharmaceutical ingredient, acetylsalicylic acid (ASA), inside tablets by using tablets containing 20% MCC as an excipient. Different levels of grinding were applied to MCC prior to tablet formulation, to intentionally cause structural variation in the MCC. The water penetration and moisture absorbability of the tablets increased with decreasing the crystallinity of MCC through higher level of grinding. More importantly, the hydrolysis of ASA inside tablets was also accelerated. These results indicate that the crystallinity of MCC has crucial effects on the pharmaceutical properties of tablets even when the tablets contain a relatively small amount of MCC. Therefore, controlling the crystal structure of excipients is important for controlling product qualities.

  5. Fine granules showing sustained drug release prepared by high-shear melt granulation using triglycerin full behenate and milled microcrystalline cellulose.

    Science.gov (United States)

    Aoki, Hajime; Iwao, Yasunori; Uchimoto, Takeaki; Noguchi, Shuji; Kajihara, Ryusuke; Takahashi, Kana; Ishida, Masayuki; Terada, Yasuko; Suzuki, Yoshio; Itai, Shigeru

    2015-01-30

    This study aimed to prepare fine granules with a diameter less than 200μm and sustained drug release properties by melt granulation. Triglycerin full behenate (TR-FB) was examined as a new meltable binder (MB) by comparison of its properties with those of glycerin monostearate (GM), widely used as MB. The effect of milling microcrystalline cellulose (MCC), an excipient for melt granulation, on the granule properties was also investigated. TR-FB was more stable during heating and storage than GM, and produced smaller granules with narrower particle size distribution, larger yield in the 106-200μm range, uniform roundness and better sustained drug release profile than those prepared with GM. Granules prepared with milled MCC had almost the same physicochemical properties as those produced with intact MCC. However, milled MCC produced granules with a more rigid structure and smaller void space than intact MCC. Consequently, the granules produced with milled MCC showed better sustained drug release behavior than those prepared with intact MCC. We successfully prepared fine granules with sustained drug release properties and diameter of less than 200μm using TR-FB and milled MCC. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Effect on Dissolvability of Microcrystalline Cellulose through Activation%微晶纤维素的活化对其溶解性能的影响

    Institute of Scientific and Technical Information of China (English)

    任丹; 李丹; 刘萍; 孙晓; 张瑞涵; 方健

    2012-01-01

    Microcrystalline cellulose(MCC) was activation treated by amine,water and ultrasonic respectively.The dissolve time in NaOH-Urea-Thiourea solution,degree of polymerization(DP),solubility,the surface of fiber,crystallinity and effect on molecule hydrogen bonding of MCC before and after activation were studied.The result showed that ultrasonic activation is better than the other two activation methods,which is more convenient to improve the dissolvability of MCC with treating power from 60 to 99 percent and treating time from 60 to 120 minutes.%用胺活化、水活化与超声波活化分别处理了微晶纤维素(MCC)。研究了活化前后微晶纤维素在氢氧化钠-尿素-硫脲中的溶解时间、聚合度、溶解度、纤维表面形态、结晶度以及对分子氢键的影响。结果表明,超声波活化较其他2种活化方法效果更好,且处理功率为60%~99%、处理时间在60~120min内更有利于改善微晶纤维素的溶解性能。

  7. Dy(3)(+) -, Sm(3)(+) -, Ce(3)(+) - and Tb(3)(+) -activated optical properties of microcrystalline BaMgP2 O7 phosphors.

    Science.gov (United States)

    Wani, J A; Dhoble, N S; Kokode, N S; Singh, Vijay; Dhoble, S J

    2017-03-01

    Photoluminescence (PL) and thermoluminescence (TL) properties of rare earth (RE) ion (RE = Dy(3)(+) , Sm(3)(+) , Ce(3)(+) , Tb(3)(+) ) activated microcrystalline BaMgP2 O7 phosphors are presented in this work. Non-doped and doped samples of BaMgP2 O7 were prepared using a solid state diffusion method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), PL and TL. The XRD measurement confirmed the phase purity of the BaMgP2 O7 host matrix. The average particle size was found through SEM measurement to be around 2 μm. All activators using the PL technique displayed characteristic excitation and emission spectra that corresponded to their typical f → f and f → d transitions respectively. Thermoluminescence measurements showed that BaMgP2 O7 :RE (RE = Dy(3)(+) , Sm(3)(+) , Tb(3)(+) , Ce(3)(+) ) and co-doped BaMgP2 O7 :Ce(3)(+) ,Tb(3)(+) phosphors have also TL behaviour.

  8. Light Scattering and Current Enhancement for Microcrystalline Silicon Thin-Film Solar Cells on Aluminium-Induced Texture Glass Superstrates with Double Texture

    Directory of Open Access Journals (Sweden)

    Yunfeng Yin

    2015-01-01

    Full Text Available Microcrystalline silicon (μc-Si:H thin-film solar cells are processed on glass superstrates having both micro- and nanoscale surface textures. The microscale texture is realised at the glass surface, using the aluminium-induced texturing (AIT method, which is an industrially feasible process enabling a wide range of surface feature sizes (i.e., 700 nm–3 μm of the textured glass. The nanoscale texture is made by conventional acid etching of the sputter-deposited transparent conductive oxide (TCO. The influence of the resulting “double texture” on the optical scattering is investigated by means of atomic force microscopy (AFM (studying the surface topology, haze measurements (studying scattering into air, and short-circuit current enhancement measurements (studying scattering into silicon. A predicted enhanced optical scattering efficiency is experimentally proven by a short-circuit current enhancement ΔIsc of up to 1.6 mA/cm2 (7.7% relative increase compared to solar cells fabricated on a standard superstrate, that is, planar glass covered with nanotextured TCO. Enhancing the autocorrelation length (or feature size of the AIT superstrates might have the large potential to improve the μc-Si:H thin-film solar cell efficiency, by reducing the shunting probability of the device while maintaining a high optical scattering performance.

  9. Ultrasound-assisted ionic liquid-based micellar extraction combined with microcrystalline cellulose as sorbent in dispersive microextraction for the determination of phenolic compounds in propolis.

    Science.gov (United States)

    Cao, Jun; Peng, Li-Qing; Du, Li-Jing; Zhang, Qi-Dong; Xu, Jing-Jing

    2017-04-22

    An ionic liquid-(IL) based micellar extraction combined with microcrystalline cellulose- (MCC) assisted dispersive micro solid-phase extraction method was developed to extract phenolic compounds from propolis. A total of 20 target compounds were identified by ultra-high- performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry. The main extraction parameters were optimized and included the ultrasonic power, ultrasonic time, sample pH, type of IL, the concentration of [C12mim]Br, extraction time, concentration of MCC, type of sorbent and type of elution solvents. Under the optimum conditions, the proposed method exhibited good linearities (r(2) ≥ 0.999) for all plant phenolic compounds with the lower limits of detection in the range of 0.21-0.41 ng/mL. The recoveries ranged from 82.74% to 97.88% for pinocembrin, chrysin and galangin. Compared with conventional solvent extraction, the present method was simpler and more efficient and required less organic solvent and a shorter extraction time. Finally, the methodology was successfully used for the extraction and enrichment of phenolic compounds in propolis. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Mechanism insight into the effect of I/P buffer layer on the performance of NIP-type hydrogenated microcrystalline silicon solar cells

    Science.gov (United States)

    Bai, Lisha; Liu, Bofei; Zhao, Jing; Suo, Song; Hou, Guofu; Zhang, Dekun; Sun, Jian; Wei, Changchun; Zhao, Ying; Zhang, Xiaodan

    2015-05-01

    A simulation and experimental study on the effect of the buffer layer at the I/P interface on the performance of NIP-type hydrogenated microcrystalline silicon (μc-Si:H) single-junction solar cells is presented. Device-quality hydrogenated amorphous silicon (a-Si:H) material as a buffer layer at the I/P interface obviously improves the performance of NIP-type μc-Si:H single-junction solar cells. In addition to the well-known mechanism that an a-Si:H I/P buffer layer can reduce the recombination current density at I/P interfaces, the optically and electrically calibrated simulations and supporting experimental results in this study illustrate that the performance improvement also originates from the mitigation of the electric screening effect due to the reduced defect density at the I/P interfaces, which reinforces the bulk electric field. Integrating an optimized hydrogen profiling strategy and adding a-Si:H I/P buffer layer yielded an initial efficiency of 9.20% for μc-Si:H single-junction solar cells with an active area of 0.27 cm2. This study may provide new ideas of further improving the performance of NIP-type μc-Si:H single-junction solar cells by mitigating the electric screening effect.

  11. Light trapping and optical losses in microcrystalline silicon pin solar cells deposited on surface-textured glass/ZnO substrates

    Energy Technology Data Exchange (ETDEWEB)

    Springer, J. [Forschungszentrum Julich GmbH, Julich (Germany). Institute of Photovoltaics; Academy of Sciences of the Czech Republic, Prague (Czech Republic). Institute of Physics; Rech, B.; Reetz, W.; Muller, J. [Forschungszentrum Julich GmbH, Julich (Germany). Institute of Photovoltaics; Vanecek, M. [Academy of Sciences of the Czech Republic, Prague (Czech Republic). Institute of Physics

    2005-01-01

    Influence of front TCO thickness, surface texture and different back reflectors on short-circuit current density and fill factor of thin film silicon solar cells were investigated. For the front TCO studies, we used ZnO layers of different thickness and applied wet chemical etching in diluted HCl. This approach allowed us to adjust ZnO texture and thickness almost independently. Additionally, we used optical modeling to calculate optical absorption losses in every layer. Results show that texture and thickness reduction of front ZnO increase quantum efficiency over the whole spectral range. The major gain is in the red/IR region. However, the higher sheet resistance of the thin ZnO causes a reduction in fill factor. In the back reflector studies, we compared four different back reflectors: ZnO/Ag, Ag, ZnO/Al and Al. ZnO/Ag yielded the best, Al the worst light trapping properties. Furthermore, the Ag back contact turned out to be superior to ZnO/Al for microcrystalline cells. Finally, the smooth ZnO/Ag back contact showed a higher reflectivity than the rough one. We prepared pin cells with rough and smooth ZnO/Ag interface, leaving the roughness of all other interfaces unchanged. (author)

  12. Decoupling crystalline volume fraction and V{sub OC} in microcrystalline silicon pin solar cells by using a {mu}c-Si:F:H intrinsic layer

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Q.; Johnson, E.V.; Djeridane, Y.; Abramov, A.; Roca i Cabarrocas, P. [LPICM-CNRS, Ecole Polytechnique, Palaiseau (France)

    2008-08-15

    Microcrystalline silicon thin film pin solar cells with a highly crystallized intrinsic {mu}c-Si:F:H absorber were prepared by RF-plasma enhanced chemical vapour deposition using SiF{sub 4} as the gas precursor. The cells were produced with a vacuum break between the doped layer and intrinsic layer depositions, and the effect of different subsequent interface treatment processes was studied. The use of an intrinsic {mu}c-Si:H p/i buffer layer before the first air break increased the short circuit current density from 22.3 mA/cm{sup 2} to 24.7 mA/cm{sup 2}. However, the use of a hydrogen-plasma treatment after both air breaks without an interface buffer layer improved both the open circuit voltage and the fill factor. Although the material used for the absorber layer showed a very high crystalline fraction and thus an increased spectral response at long wavelengths, an open-circuit voltage (V{sub OC}) of 0.523 V was nevertheless observed. Such a value of V{sub OC} is higher than is typically obtained in devices that employ a highly crystallized absorber as reported in the literature (see abstract figure). Using a hydrogen-plasma treatment, a single junction {mu}c-Si:F:H pin solar cell with an efficiency of 8.3% was achieved. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  13. Non-destructive determination of anisotropic mechanical properties of pharmaceutical solid dosage forms.

    Science.gov (United States)

    Akseli, I; Hancock, B C; Cetinkaya, C

    2009-07-30

    The mechanical property anisotropy of compacts made from four commercially available pharmaceutical excipient powders (microcrystalline cellulose, lactose monohydrate, ascorbic acid, and aspartame) was evaluated. The speed of pressure (longitudinal) waves in the uni-axially compressed cubic compacts of each excipient in the three principle directions was determined using a contact ultrasonic method. Average Young's moduli of each compact in the axial (x) and radial (y and z) directions were characterized. The contact ultrasonic measurements revealed that average Young's modulus values vary with different testing orientations which indicate Young's modulus anisotropy in the compacts. The extent of Young's modulus anisotropy was quantified by using a dimensionless ratio and was found to be significantly different for each material (microcrystalline cellulose>lactose>aspartame>ascorbic acid). It is also observed that using the presented contact method, compacts at high solid fraction (0.857-0.859) could be differentiated than those at the solid fraction of 0.85 in their groups. The presented contact ultrasonic method is an attractive tool since it has the advantages of being sensitive to solid fraction ratio, non-destructive, requiring small amount of material and rapid. It is noteworthy that, since the approach provides insight into the performance of common pharmaceutical materials and fosters increased process knowledge, it can be applied to broaden the understanding of the effect of the mechanical properties on the performance (e.g., disintegration profiles) of solid oral dosage forms.

  14. Stages in spheronisation: evolution of pellet size and shape during spheronisation of microcrystalline cellulose-based paste extrudates

    OpenAIRE

    2014-01-01

    This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.powtec.2014.10.014 The stages of extrudate breakup and rounding to form spheroidal pellets was investigated for MCC/water pastes and some MCC/water/calcium carbonate pastes using the interrupted technique reported by Lau et al. (2014). A new quantitative parameter, named ‘dumb-bellity’, was developed to monitor the formation and disappearance of ‘dumb-bell’ shaped pellets in...

  15. Secondary growth mechanism of SiGe islands deposited on a mixed-phase microcrystalline Si by ion beam co-sputtering.

    Science.gov (United States)

    Ke, S Y; Yang, J; Qiu, F; Wang, Z Q; Wang, C; Yang, Y

    2015-11-01

    We discuss the SiGe island co-sputtering deposition on a microcrystalline silicon (μc-Si) buffer layer and the secondary island growth based on this pre-SiGe island layer. The growth phenomenon of SiGe islands on crystalline silicon (c-Si) is also investigated for comparison. The pre-SiGe layer grown on μc-Si exhibits a mixed-phase structure, including SiGe islands and amorphous SiGe (a-SiGe) alloy, while the layer deposited on c-Si shows a single-phase island structure. The preferential growth and Ostwald ripening growth are shown to be the secondary growth mechanism of SiGe islands on μc-Si and c-Si, respectively. This difference may result from the effect of amorphous phase Si (AP-Si) in μc-Si on the island growth. In addition, the Si-Ge intermixing behavior of the secondary-grown islands on μc-Si is interpreted by constructing the model of lateral atomic migration, while this behavior on c-Si is ascribed to traditional uphill atomic diffusion. It is found that the aspect ratios of the preferential-grown super islands are higher than those of the Ostwald-ripening ones. The lower lateral growth rate of super islands due to the lower surface energy of AP-Si on the μc-Si buffer layer for the non-wetting of Ge at 700 °C and the stronger Si-Ge intermixing effect at 730 °C may be responsible for this aspect ratio difference.

  16. Virus-Like Particle (VLP Plus Microcrystalline Tyrosine (MCT Adjuvants Enhance Vaccine Efficacy Improving T and B Cell Immunogenicity and Protection against Plasmodium berghei/vivax

    Directory of Open Access Journals (Sweden)

    Gustavo Cabral-Miranda

    2017-05-01

    Full Text Available Vaccination is the most effective prophylactic tool against infectious diseases. Despite continued efforts to control malaria, the disease still generally represents a significant unmet medical need. Microcrystalline tyrosine (MCT is a well described depot used in licensed allergy immunotherapy products and in clinical development. However, its proof of concept in prophylactic vaccines has only recently been explored. MCT has never been used in combination with virus-like particles (VLPs, which are considered to be one of the most potent inducers of cellular and humoral immune responses in mice and humans. In the current study we assessed the potential of MCT to serve as an adjuvant in the development of a vaccine against malaria either alone or combined with VLP using Plasmodium vivax thrombospondin-related adhesive protein (TRAP as a target antigen. We chemically coupled PvTRAP to VLPs derived from the cucumber mosaic virus fused to a universal T-cell epitope of the tetanus toxin (CMVtt, formulated with MCT and compared the induced immune responses to PvTRAP formulated in PBS or Alum. The protective capacity of the various formulations was assessed using Plasmodium berghei expressing PvTRAP. All vaccine formulations using adjuvants and/or VLP increased humoral immunogenicity for PvTRAP compared to the antigen alone. The most proficient responder was the group of mice immunized with the vaccine formulated with PvTRAP-VLP + MCT. The VLP-based vaccine formulated in MCT also induced the strongest T cell response and conferred best protection against challenge with recombinant Plasmodium berghei. Thus, the combination of VLP with MCT may take advantage of the properties of each component and appears to be an alternative biodegradable depot adjuvant for development of novel prophylactic vaccines.

  17. Development of Hydrogenated Microcrystalline Silicon-Germanium Alloys for Improving Long-Wavelength Absorption in Si-Based Thin-Film Solar Cells

    Directory of Open Access Journals (Sweden)

    Yen-Tang Huang

    2014-01-01

    Full Text Available Hydrogenated microcrystalline silicon-germanium (μc-Si1-xGex:H alloys were developed for application in Si-based thin-film solar cells. The effects of the germane concentration (RGeH4 and the hydrogen ratio (RH2 on the μc-Si1-xGex:H alloys and the corresponding single-junction thin-film solar cells were studied. The behaviors of Ge incorporation in a-Si1-xGex:H and μc-Si1-xGex:H were also compared. Similar to a-Si1-xGex:H, the preferential Ge incorporation was observed in μc-Si1-xGex:H. Moreover, a higher RH2 significantly promoted Ge incorporation for a-Si1-xGex:H, while the Ge content was not affected by RH2 in μc-Si1-xGex:H growth. Furthermore, to eliminate the crystallization effect, the 0.9 μm thick absorbers with a similar crystalline volume fraction were applied. With the increasing RGeH4, the accompanied increase in Ge content of μc-Si1-xGex:H narrowed the bandgap and markedly enhanced the long-wavelength absorption. However, the bias-dependent EQE measurement revealed that too much Ge incorporation in absorber deteriorated carrier collection and cell performance. With the optimization of RH2 and RGeH4, the single-junction μc-Si1-xGex:H cell achieved an efficiency of 5.48%, corresponding to the crystalline volume fraction of 50.5% and Ge content of 13.2 at.%. Compared to μc-Si:H cell, the external quantum efficiency at 800 nm had a relative increase by 33.1%.

  18. Microcrystalline Silicon Films and Solar Cells Prepared by Photochemical Vapor Deposition on Textured SnO2 with High Haze Factors

    Science.gov (United States)

    Zhao, Ying; Miyajima, Shinsuke; Ide, Yoshinori; Yamada, Akira; Konagai, Makoto

    2002-11-01

    Microcrystalline silicon (μc-Si) films and solar cells were prepared by mercury-sensitized photochemical vapor deposition (photo-CVD). The changes in the structural properties of a series of μc-Si films grown under various H2 dilution and deposition pressure conditions were discussed. The results indicated that the properties of μc-Si films depend strongly on the atomic hydrogen. The microstructures of μc-Si films on textured SnO2 with different haze factors (from 13% to 65%) were observed with a scanning electron microscope and a transmission electron microscope. The observations revealed that the μc-Si layers grew from the initial stage of deposition with columnar grains and that they were conformal to the surface of textured SnO2. The grain boundary density of μc-Si film on SnO2 with higher haze factors was lower than that on SnO2 with lower haze factors. The effect of textured SnO2 with different haze ratios on p-i-n μc-Si cell characteristics was discussed and it was found that the higher haze factors showed a higher degree of light trapping in our μc-Si cells. We deposited μc-Si cells with an intrinsic μc-Si layer thickness of 430 nm on a textured SnO2 sample with a haze factor of 42% and achieved a conversion efficiency of 6.55%.

  19. Conformation of Sodium Microcrystalline Cellulose Sulfate in Aqueous Solution%微晶纤维素硫酸钠溶液的构象

    Institute of Scientific and Technical Information of China (English)

    李琳; 熊文雯; 王兆梅

    2006-01-01

    Sodium microcrystalline cellulose sulfate ( NaCSMC) is a new type of effective anti-coagulant, whose anti-coagulant activity is closely related to the conformation in solution. In order to reveal the anti-coagulant activity of NaCSMC, the conformation of NaCSMC in aqueous solution was investigated by the optical rotation measurement, the viscosity analysis and the Congo red helix-coil transition analysis. The measurement results of optical rotation show that the conformation of NaCSMC is regular in neutral or weak alkaline solution. The same results can also be obtained by means of viscosity analysis. Moreover, it is indicated by the Congo red helix-coil transition analysis that the conformation of NaCSMC in aqueous solution is of not only regular conformation but also single helix and multi-helix structures.%微晶纤维素硫酸钠是一种具有显著抗凝血活性的物质,其抗凝活性与其在溶液中的构象密切相关.为了解其抗凝活性,文中通过旋光度分析、粘度分析和刚果红螺旋-线团过渡分析,研究了微晶纤维素硫酸钠溶液的构象.旋光度分析表明,微晶纤维素硫酸钠在水溶液或弱碱溶液中具有规则的空间构象;由粘度分析也可得出同样的结果;刚果红螺旋-线团过渡分析表明,微晶纤维素硫酸钠在溶液中具有规则的空间构象,同时具有单螺旋结构与高级螺旋结构.

  20. To Evaluate the Effect of Solvents and Different Relative Humidity Conditions on Thermal and Rheological Properties of Microcrystalline Cellulose 101 Using METHOCEL™ E15LV as a Binder.

    Science.gov (United States)

    Jagia, Moksh; Trivedi, Maitri; Dave, Rutesh H

    2016-08-01

    The solvent used for preparing the binder solution in wet granulation can affect the granulation end point and also impact the thermal, rheological, and flow properties of the granules. The present study investigates the effect of solvents and percentage relative humidity (RH) on the granules of microcrystalline cellulose (MCC) with hydroxypropyl methyl cellulose (HPMC) as the binder. MCC was granulated using 2.5% w/w binder solution in water and ethanol/water mixture (80:20 v/v). Prepared granules were dried until constant percentage loss on drying, sieved, and further analyzed. Dried granules were exposed to different percentage RH for 48 h at room temperature. Powder rheometer was used for the rheological and flow characterization, while thermal effusivity and differential scanning calorimeter were used for thermal analysis. The thermal effusivity values for the wet granules showed a sharp increase beginning 50% w/w binder solution in both cases, which reflected the over-wetting of granules. Ethanol/water solvent batches showed greater resistance to flow as compared to the water solvent batches in the wet granule stage, while the reverse was true for the dried granule stage, as evident from the basic flowability energy values. Although the solvents used affected the equilibration kinetics of moisture content, the RH-exposed granules remained unaffected in their flow properties in both cases. This study indicates that the solvents play a vital role on the rheology and flow properties of MCC granules, while the different RH conditions have little or no effect on them for the above combination of solvent and binder.

  1. Tidal Forms

    Science.gov (United States)

    Bolla Pittaluga, M.; Seminara, G.; Tambroni, N.

    2003-04-01

    We give an overview of some recent investigations on the mechanics of the processes whereby forms develop in tidal environments. The viewpoint taken here is mechanistic. Some of the questions which deserve an answer may be summarised as follows: i) do tidal channels tend to some altimetric long term equilibrium? ii) why are they typically convergent and weakly meandering? iii) how is such equilibrium affected by the hydrodynamics and morphodynamics of tidal inlets? iv) what is the hydrodynamic and morphodynamic role played by tidal flats adjacent to the channels? Some of the above questions have received a considerable attention in the last few years. Schuttelaars and de Swart (1996), Lanzoni and Seminara (2002) and, more recently, Bolla Pittaluga (2003) have investigated the first problem. In particular, the latter two contributions have shown that a straight tidal channel connected to a tidal sea at one end and closed at the other end tends to reach a long term equilibrium profile, which is slightly concave seaward and convex landward where a beach forms. The equilibrium profile is strongly sensitive to the harmonic content of the tidal forcing as well as to the value of sediment concentration established by the coastal hydrodynamics in the far field of the inlet region. Less important are the effect of channel convergence and the role of settling lag in the transport of suspended load. Insufficient attention has been devoted to the understanding of what mechanisms control channel convergence and meandering, though some similarities and differences between tidal and fluvial channels have emerged from some recent works. In particular, free bars form in tidal channels due to an instability mechanism essentially similar to that occurring under steady conditions though the oscillatory character of the flow field makes the bar pattern non migrating (Seminara and Tubino, 2001). Similarly, forced bars in curved tidal channels are driven by the development of

  2. Preparation and microwave properties of Y-type magnetoplumbite microcrystalline glass ceramic with the composition 0.5(Ba{sub 2}Zn{sub Z}Co{sub 2-Z}Fe{sub 12}O{sub 22}).0.5SiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, H.; Yao, X.; Zhang, L. [High Temperature Ceramics Inst., Zhengzhou Univ., Henan (China)

    2002-02-01

    The citrate sol-gel synthesis technique was used to prepared Ba{sub 2}Zn{sub Z}Co{sub 2-Z}Fe{sub 12}O{sub 22}/SiO{sub 2} microcrystalline glass ceramic with Z=2.0,1.6,1.2, and 0.8. Several methods such as X-ray diffractometry, scanning electron microscopy and HP vector network analyzer were used to obtain detailed information on the crystallography and magnetic properties of Ba{sub 2}Zn{sub Z}Co{sub 2-Z}Fe{sub 12}O{sub 22}/SiO{sub 2} microcrystalline glass ceramic. The correlation of the formation of Ba{sub 2}Zn{sub Z}Co{sub 2-Z}Fe{sub 12}O{sub 22}/SiO{sub 2} microcrystalline glass ceramic with thermal treatment was studied. The complex dielectric constant and complex permeability of microcrystalline glass ceramic-paraffin wax composites were measured by the transmission/reflection coaxial line method in the range from 100MHz to 6 GHz. The effects of composition, annealing temperature and measuring frequency on complex permittivity and permeability of Ba{sub 2}Zn{sub Z}Co{sub 2-Z}Fe{sub 12}O{sub 22}/SiO{sub 2} microcrystalline glass ceramic were also investigated. (orig.)

  3. Prevalence and trends of cellulosics in pharmaceutical dosage forms.

    Science.gov (United States)

    Mastropietro, David J; Omidian, Hossein

    2013-02-01

    Many studies have shown that cellulose derivatives (cellulosics) can provide various benefits when used in virtually all types of dosage forms. Nevertheless, the popularity of their use in approved drug products is rather unknown. This research reports the current prevalence and trends of use for 15 common cellulosics in prescription drug products. The cellulosics were powdered and microcrystalline cellulose (MCC), ethyl cellulose, hydroxypropyl cellulose (HPC), hydroxyethyl cellulose (HEC), hypromellose (HPMC), HPMC phthalate, HPMC acetate succinate, cellulose acetate (CA), CA phthalate, sodium (Na) and calcium (Ca) carboxymethylcellulose (CMC), croscarmellose sodium (XCMCNa), methyl cellulose, and low substituted HPC. The number of brand drug products utilizing each cellulosics was determined using the online drug index Rxlist. A total of 607 brand products were identified having one or more of the cellulosics as an active or inactive ingredient. An array of various dosage forms was identified and revealed HPMC and MCC to be the most utilized cellulosics in all products followed by XCMCNa and HPC. Many products contained two or more cellulosics in the formulation (42% containing two, 23% containing three, and 4% containing 4-5). The largest combination occurrence was HPMC with MCC. The use of certain cellulosics within different dosage form types was found to contain specific trends. All injectables utilized only CMCNa, and the same with all ophthalmic solutions utilizing HPMC, and otic suspensions utilizing HEC. Popularity and trends regarding cellulosics use may occur based on many factors including functionality, safety, availability, stability, and ease of manufacturing.

  4. Effect of TCO/μc-Si:H Interface Modification on Hydrogenated Microcrystalline Silicon Thin-Film Solar Cells

    Directory of Open Access Journals (Sweden)

    Shin-Wei Liang

    2013-01-01

    Full Text Available The effects of H2 plasma exposure on optical, electrical, and structural properties of fluorine-doped tin oxide (FTO and AZO/FTO substrates have been investigated. With increasing the time of H2-plasma exposure, the hydrogen radical and ions penetrated through the FTO surface to form more suboxides such as SnO and metallic Sn, which was confirmed by the XPS analysis. The Sn reduction on the FTO surface can be effectively eliminated by capping the FTO with a very thin layer of sputtered aluminum-doped zinc oxide (AZO, as confirmed by the XPS analysis. By using the AZO/FTO as front TCO with the subsequent annealing, the p-i-n μc-Si:H cell exhibited a significantly enhanced JSC from 15.97 to 19.40 mA/cm2 and an increased conversion efficiency from 5.69% to 7.09%. This significant enhancement was ascribed to the effective elimination of the Sn reduction on the FTO surface by the thin AZO layer during the Si-based thin-film deposition with hydrogen-rich plasma exposure. Moreover, the subsequent annealing of the sputtered AZO could lead to less defects as well as a better interface of AZO/FTO.

  5. Characteristics of microcrystalline cellulose and its application in neutral dairy beverage%微晶纤维素特性及其在中性乳饮料中的应用研究

    Institute of Scientific and Technical Information of China (English)

    薛玉清; 舒成亮; 余立意; 杨忻怡; 欧凯; 李言郡; 马海然

    2016-01-01

    目的:研究胶态微晶纤维素(microcrystalline cellulose, MCC)的流变特性及在中性乳饮料中的应用。方法通过使用流变仪、粘度仪分析研究胶态微晶纤维素的特性,包括触变性、粘度、悬浮能力和对抗热的稳定性。以中性乳饮料为体系,并结合产品离心沉淀率和体系浊度保留率状况,归纳微晶纤维素作为稳定剂使用时的关键影响因素。结果中性乳饮料体系选择微晶纤维素作为稳定剂,产品最终的离心沉淀率大大下降,浊度保留率有所提高。结论微晶纤维素复配卡拉胶、结冷胶对中性乳饮料的稳定性有明显的改善。%Objective To investigate the rheological properties of the gel microcrystalline cellulose (MCC) and its application in neutral dairy beverage.MethodsThe properties including thixotropy, viscosity, suspending ability and thermal stability of microcrystalline cellulose were analyzed using rheometer and viscosity meter. Based on neutral beverage system, the key factors affecting the properties of stabilizer MCC were summarized by combining centrifugal sedimentation rate and system turbidity retention rate.ResultsWith a proper selection of MCC as the stabilizer in neutral dairy beverage system, the centrifugal sedimentation rate of final product greatly reduced with an increased turbidity retention rate.ConclusionMCC combined with carrageenan and gellan gum can improve the stability of the neutral dairy beverage.

  6. Characteristics of microcrystalline cellulose and its application in neutral dairy beverage%微晶纤维素特性及其在中性乳饮料中的应用研究

    Institute of Scientific and Technical Information of China (English)

    薛玉清; 舒成亮; 余立意; 杨忻怡; 欧凯; 李言郡; 马海然

    2016-01-01

    ABSTRACT:Objective To investigate the rheological properties of the gel microcrystalline cellulose (MCC) and its application in neutral dairy beverage. Methods The properties including thixotropy, viscosity, suspending ability and thermal stability of microcrystalline cellulose were analyzed using rheometer and viscosity meter. Based on neutral beverage system, the key factors affecting the properties of stabilizer MCC were summarized by combining centrifugal sedimentation rate and system turbidity retention rate. Results With a proper selection of MCC as the stabilizer in neutral dairy beverage system, the centrifugal sedimentation rate of final product greatly reduced with an increased turbidity retention rate. Conclusion MCC combined with carrageenan and gellan gum can improve the stability of the neutral dairy beverage.%目的:研究胶态微晶纤维素(microcrystalline cellulose, MCC)的流变特性及在中性乳饮料中的应用。方法通过使用流变仪、粘度仪分析研究胶态微晶纤维素的特性,包括触变性、粘度、悬浮能力和对抗热的稳定性。以中性乳饮料为体系,并结合产品离心沉淀率和体系浊度保留率状况,归纳微晶纤维素作为稳定剂使用时的关键影响因素。结果中性乳饮料体系选择微晶纤维素作为稳定剂,产品最终的离心沉淀率大大下降,浊度保留率有所提高。结论微晶纤维素复配卡拉胶、结冷胶对中性乳饮料的稳定性有明显的改善。

  7. Contributors Form

    Directory of Open Access Journals (Sweden)

    Chief Editor

    2016-06-01

    to produce preprints or reprints and translate into languages other than English for sale or free distribution; and 4 the right to republish the work in a collection of articles in any other mechanical or electronic format. We give the rights to the corresponding author to make necessary changes as per the request of the journal, do the rest of the correspondence on our behalf and he/she will act as the guarantor for the manuscript on our behalf. All persons who have made substantial contributions to the work reported in the manuscript, but who are not contributors, are named in the Acknowledgment and have given me/us their written permission to be named. If I/we do not include an Acknowledgment that means I/we have not received substantial contributions from non-contributors and no contributor has been omitted.S NoAuthors' NamesContribution (IJCME Guidelines{1 substantial contributions to conception and design, acquisition of data, or analysis and interpretation of data; 2 drafting the article or revising it critically for important intellectual content; and 3 final approval of the version to be published. Authors should meet conditions 1, 2, and 3}.SignatureDate                              Note: All the authors are required to sign independently in this form in the sequence given above. In case an author has left the institution/country and whose whereabouts are not known, the senior author may sign on his/her behalf taking the responsibility.No addition/deletion/ or any change in the sequence of the authorship will be permissible at a later stage, without valid reasons and permission of the Editor.If the authorship is contested at any stage, the article will be either returned or will not be processed for publication till the issue is solved.Maximum up to 4 authors for short communication and up to 6 authors for original article.

  8. Development of Tandem Amorphous/Microcrystalline Silicon Thin-Film Large-Area See-Through Color Solar Panels with Reflective Layer and 4-Step Laser Scribing for Building-Integrated Photovoltaic Applications

    Directory of Open Access Journals (Sweden)

    Chin-Yi Tsai

    2014-01-01

    Full Text Available In this work, tandem amorphous/microcrystalline silicon thin-film large-area see-through color solar modules were successfully designed and developed for building-integrated photovoltaic applications. Novel and key technologies of reflective layers and 4-step laser scribing were researched, developed, and introduced into the production line to produce solar panels with various colors, such as purple, dark blue, light blue, silver, golden, orange, red wine, and coffee. The highest module power is 105 W and the highest visible light transmittance is near 20%.

  9. Effect of roll compaction on granule size distribution of microcrystalline cellulose-mannitol mixtures: computational intelligence modeling and parametric analysis.

    Science.gov (United States)

    Kazemi, Pezhman; Khalid, Mohammad Hassan; Pérez Gago, Ana; Kleinebudde, Peter; Jachowicz, Renata; Szlęk, Jakub; Mendyk, Aleksander

    2017-01-01

    Dry granulation using roll compaction is a typical unit operation for producing solid dosage forms in the pharmaceutical industry. Dry granulation is commonly used if the powder mixture is sensitive to heat and moisture and has poor flow properties. The output of roll compaction is compacted ribbons that exhibit different properties based on the adjusted process parameters. These ribbons are then milled into granules and finally compressed into tablets. The properties of the ribbons directly affect the granule size distribution (GSD) and the quality of final products; thus, it is imperative to study the effect of roll compaction process parameters on GSD. The understanding of how the roll compactor process parameters and material properties interact with each other will allow accurate control of the process, leading to the implementation of quality by design practices. Computational intelligence (CI) methods have a great potential for being used within the scope of quality by design approach. The main objective of this study was to show how the computational intelligence techniques can be useful to predict the GSD by using different process conditions of roll compaction and material properties. Different techniques such as multiple linear regression, artificial neural networks, random forest, Cubist and k-nearest neighbors algorithm assisted by sevenfold cross-validation were used to present generalized models for the prediction of GSD based on roll compaction process setting and material properties. The normalized root-mean-squared error and the coefficient of determination (R(2)) were used for model assessment. The best fit was obtained by Cubist model (normalized root-mean-squared error =3.22%, R(2)=0.95). Based on the results, it was confirmed that the material properties (true density) followed by compaction force have the most significant effect on GSD.

  10. High Mobility Microcrystalline Silicon Thin-Film Transistors%基于高迁移率微晶硅的薄膜晶体管

    Institute of Scientific and Technical Information of China (English)

    CHAN Kah-Yoong; Eerle Bunte; Helmut Stiebig; Dietmar Knipp

    2008-01-01

    Microcrystalline silicon (μc-Si: H) has recently been proven to be a promising material for thin- film transistors (TFTs). We present μc-Si.H TFTs fabricated by plasma-enhanced chemical vapor deposi-tion at temperatures below 200℃ in a condition similar to the fabrication of amorphous silicon TFTs. The μc-Si. H TFTs exhibit device mobilities exceeding 30 cm2/Vs and threshold voltages in the range of 2.5 V.Such high mobilities are observed for long channel devices (50~200 μm). For short channel device (2μm), the mobility reduces to 7 cm2/Vs. Furthermore the threshold voltage of the TFTs decreases with de-creasing channel length. A simple model is developed, which explains the observed reduction of the device mobility and threshold voltage with decreasing channel length by the influence of drain and source contact resistance.%近年来,微晶硅(μc-Si:H)被认为是一种制作 TFT 的有前景的材料.采用PECVD法,在低于200℃时制作了微晶硅TFTs,其制作条件类似于非晶态 TFTs.微晶硅 TFTs 器件的迁移率超过了 30 cm2/Vs,而阈值电压是 2.5 V.在长沟道器件(50~200 μm)中观测到了这种高迁移率.但对于短沟道器件(2 μm),迁移率就降低到了7 cm2/Vs.此外,该 TFTs 的阈值电压随着沟道长度的减少而增大.文章采用了一种简单模型解释了迁移率、阈值电压随着沟道长度的缩短而分别减少、增加的原因在于源漏接触电阻的影响.

  11. Enzymatic properties of Thermoanaerobacterium thermosaccharolyticum β-glucosidase fused to Clostridium cellulovorans cellulose binding domain and its application in hydrolysis of microcrystalline cellulose.

    Science.gov (United States)

    Zhao, Linguo; Pang, Qian; Xie, Jingcong; Pei, Jianjun; Wang, Fei; Fan, Song

    2013-11-14

    The complete degradation of the cellulose requires the synergistic action of endo-β-glucanase, exo-β-glucanase, and β-glucosidase. But endo-β-glucanase and exo-β-glucanase can be recovered by solid-liquid separation in cellulose hydrolysis by their cellulose binding domain (CBD), however, the β-glucosidases cannot be recovered because of most β-glucosidases without the CBD, so additional β-glucosidases are necessary for the next cellulose degradation. This will increase the cost of cellulose degradation. The glucose-tolerant β-glucosidase (BGL) from Thermoanaerobacterium thermosaccharolyticum DSM 571 was fused with cellulose binding domain (CBD) of Clostridium cellulovorans cellulosome anchoring protein by a peptide linker. The fusion enzyme (BGL-CBD) gene was overexpressed in Escherichia coli with the maximum β-glucosidase activity of 17 U/mL. Recombinant BGL-CBD was purified by heat treatment and following by Ni-NTA affinity. The enzymatic characteristics of the BGL-CBD showed optimal activities at pH 6.0 and 65°C. The fusion of CBD structure enhanced the hydrolytic efficiency of the BGL-CBD against cellobiose, which displayed a 6-fold increase in Vmax/Km in comparison with the BGL. A gram of cellulose was found to absorb 643 U of the fusion enzyme (BGL-CBD) in pH 6.0 at 50°C for 25 min with a high immobilization efficiency of 90%. Using the BGL-CBD as the catalyst, the yield of glucose reached a maximum of 90% from 100 g/L cellobiose and the BGL-CBD could retain over 85% activity after five batches with the yield of glucose all above 70%. The performance of the BGL-CBD on microcrystalline cellulose was also studied. The yield of the glucose was increased from 47% to 58% by adding the BGL-CBD to the cellulase, instead of adding the Novozyme 188. The hydrolytic activity of BGL-CBD is greater than that of the Novozyme 188 in cellulose degradation. The article provides a prospect to decrease significantly the operational cost of the hydrolysis process.

  12. Activation of Microcrystalline Cellulose by Two-step Method and Its Use in Immobilization of Papain%两步法活化微晶纤维素及在固定木瓜蛋白酶中的应用

    Institute of Scientific and Technical Information of China (English)

    郭刚军; 马林; 谢文林; 陈国雄; 古练权

    2001-01-01

    Immobilized papain was prepared using microcrystalline cellulos as support which was activated by two-step method.The microcrystalline cellulose was first activated with p-toluenesulfonyl chloride, followed by coupling with ethyl diamine.After treated with glutaraldehyde, papain was immobilized to the support.Immobilized papain was obtained with activity 103 U/g support and high stability.%微晶纤维素经过两步活化,可在温和条件下实现木瓜蛋白酶固定化.用对甲基苯磺酰氯活化微晶纤维素后,与乙二胺反应向载体引入有机胺基团,再用戊二醒处理所得的二次活化载体可在温和条件固定木瓜蛋白酶.所得固定化酶活力为103 U/g载体,与溶液酶比较,热稳定性有明显提高.

  13. STUDY ON PREPARATION, COMPLEX PERMITTIVITY,PERMEABILITY AND MICROWAVE PROPERTIES OF BaZnzCo2- zFe16O27/SiO2 MICROCRYSTALLINE GLASS CERAMICS

    Institute of Scientific and Technical Information of China (English)

    H.J. Zhang; X.L. Jia; X. Yao; L. Y. Zhang

    2003-01-01

    BaZnz Co2- z Fe16 O27 /SiO2 microcrystalline glass ceramics with Z=0.0, 0.5, 0.8 and 1.1 were prepared at temperature 1200℃ for 5h by citrate sol-gel process. The complex dielectric constant and complex permeability of BaZnzCo2-zFe16O27/SiO2-paraffin wax composites had been measured. Both the complex dielectric constant and dielectric loss exhibit almost no variation with frequency in 0.1-6.0GHz. The real part of permeability decreases with increasing frequency for all samples, and the imaginary part of permeability exhibits a clear resonance peak at 1.44GHz for Co2 W/SiO2,1.32GHz for Zn0.5 Co1.5 W/SiO2, 1.20GHz for Zn0.8Co1.2 W/SiO2, and 1.08GHz for Zn1.1 Co0.9 W/SiO2. It is also showed that the content of zinc has a close effect on the magnetic properties of BaZnz Co2-zFe16 O27/SiO2 microcrystalline glass ceramics,the greater the zinc content, the higher the values of imaginary part of permeability and magnetic loss.

  14. Densified waste form and method for forming

    Science.gov (United States)

    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.

  15. Forming MOFs into spheres by use of molecular gastronomy methods.

    Science.gov (United States)

    Spjelkavik, Aud I; Aarti; Divekar, Swapnil; Didriksen, Terje; Blom, Richard

    2014-07-14

    A novel method utilizing hydrocolloids to prepare nicely shaped spheres of metal-organic frameworks (MOFs) has been developed. Microcrystalline CPO-27-Ni particles are dispersed in either alginate or chitosan solutions, which are added dropwise to solutions containing, respectively, either divalent group 2 cations or base that act as gelling agents. Well-shaped spheres are immediately formed, which can be dried into spheres containing mainly MOF (>95 wt %). The spheronizing procedures have been optimized with respect to maximum specific surface area, shape, and particle density of the final sphere. At optimal conditions, well-shaped 2.5-3.5 mm diameter CPO-27-Ni spheres with weight-specific surface areas <10 % lower than the nonformulated CPO-27-Ni precursor, and having sphere densities in the range 0.8 to 0.9 g cm(-3) and particle crushing strengths above 20 N, can be obtained. The spheres are well suited for use in fixed-bed catalytic or adsorption processes.

  16. Development of Amorphous/Microcrystalline Silicon Tandem Thin-Film Solar Modules with Low Output Voltage, High Energy Yield, Low Light-Induced Degradation, and High Damp-Heat Reliability

    Directory of Open Access Journals (Sweden)

    Chin-Yi Tsai

    2014-01-01

    Full Text Available In this work, tandem amorphous/microcrystalline silicon thin-film solar modules with low output voltage, high energy yield, low light-induced degradation, and high damp-heat reliability were successfully designed and developed. Several key technologies of passivation, transparent-conducting-oxide films, and cell and segment laser scribing were researched, developed, and introduced into the production line to enhance the performance of these low-voltage modules. A 900 kWp photovoltaic system with these low-voltage panels was installed and its performance ratio has been simulated and projected to be 92.1%, which is 20% more than the crystalline silicon and CdTe counterparts.

  17. Chemical co-precipitation synthesis and photoluminescence of Eu{sup 3+} or Dy{sup 3+} doped Zn{sub 3}Nb{sub 2}O{sub 8} microcrystalline phosphors from hybrid precursors

    Energy Technology Data Exchange (ETDEWEB)

    Xiao Xiuzhen [Department of Chemistry, Tongji University, Siping Road 1239, Shanghai 200092 (China); Yan Bing [Department of Chemistry, Tongji University, Siping Road 1239, Shanghai 200092 (China)]. E-mail: byan@tongji.edu.cn

    2007-01-25

    Dy{sup 3+}, Eu{sup 3+} activated Zn{sub 3}Nb{sub 2}O{sub 8} phosphors were synthesized via a modified chemical co-precipitation technology with the different concentration. In order to obtain the hybrid precursors, the rare earth coordination polymers with salicylic acid were used as precursors and the polyethylene glycol (PEG) was used as dispersing media. Their microstructure and micromorphology have been analyzed by X-ray powder diffraction (XRD) and scanning electronic microscope (SEM), which indicates that there exist some novel column-like microcrystalline particles with 0.5-5.0 {mu}m sizes in dimension. The characteristic transition of Dy{sup 3+} and Eu{sup 3+} were identified in the emission spectra and the optimum concentration of activators in Zn{sub 3}Nb{sub 2}O{sub 8} was found.

  18. Careers (A Course of Study). Unit V: Forms, Forms, Forms.

    Science.gov (United States)

    Turley, Kay

    Designed to enable special needs students to understand and complete various job-related forms, this set of activities devoted to forms encountered before and after one obtains a job is the fifth in a nine-unit secondary level careers course intended to provide handicapped students with the knowledge and tools necessary to succeed in the world of…

  19. Pharmaceutical approaches to preparing pelletized dosage forms using the extrusion-spheronization process.

    Science.gov (United States)

    Trivedi, Namrata R; Rajan, Maria Gerald; Johnson, James R; Shukla, Atul J

    2007-01-01

    Pelletized dosage forms date back to the 1950s, when the first product was introduced to the market. Since then, these dosage forms have gained considerable popularity because of their distinct advantages, such as ease of capsule filling because of better flow properties of the spherical pellets; enhancement of drug dissolution; ease of coating; sustained, controlled, or site-specific delivery of the drug from coated pellets; uniform packing; even distribution in the GI tract; and less GI irritation. Pelletized dosage forms can be prepared by a number of techniques, including drug layering on nonpareil sugar or microcrystalline cellulose beads, spray drying, spray congealing, rotogranulation, hot-melt extrusion, and spheronization of low melting materials or extrusion-spheronization of a wet mass. This review discusses recent developments in the pharmaceutical approaches that have been used to prepare pelletized dosage forms using the extrusion-spheronization process over the last decade. The review is divided into three parts: the first part discusses the extrusion-spheronization process, the second part discusses the effect of varying formulation and process parameters on the properties of the pellets, and the last part discusses the different approaches that have been used to prepare pelletized dosage forms using the extrusion-spheronization process.

  20. 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.......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....

  1. 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.

  2. Comparative evaluation of the efficacy of synthetic nanocrystalline hydroxyapatite bone graft (Ostim® and synthetic microcrystalline hydroxyapatite bone graft (Osteogen® in the treatment of human periodontal intrabony defects: A clinical and denta scan study

    Directory of Open Access Journals (Sweden)

    Monika Kamboj

    2016-01-01

    Full Text Available Background: To evaluate the relative efficacy of synthetic nanocrystalline hydroxyapatite (HA (Ostim® and microcrystalline HA (Osteogen® bone grafts in the treatment of human periodontal intrabony defects clinically and radiographically through denta scan. Materials and Methods: Ten chronic periodontitis patients with bilateral intrabony periodontal defects of ≥2 mm radiographic defect depth below 55 years of age were selected randomly and treated with synthetic nanocrystalline HA (Ostim® or synthetic microcrystalline HA (Osteogen® bone graft. Clinical parameters including probing depth (PD and clinical attachment level (CAL were measured preoperatively and postoperatively at 3 and 6 months for each of the defects using an occlusal acrylic stent. Radiographic parameters were measured with the help of denta scan preoperatively and postoperatively at 6 months. Results: At 6 months following therapy, the Osteogen® group showed a reduction in mean PD from 11.10 ± 1.663 to 8.50 ± 0.850 mm and a change in mean CAL from 6.30 ± 1.160 to 3.40 ± 0.516 mm, whereas in the Ostim® group, the mean PD decreased from 11.20 ± 0.919 to 8.30 ± 0.823 mm and mean CAL decreased from 6.10 ± 0.738 to 3.30 ± 0.483 mm. At 6 months following therapy, denta scan showed a reduction in mean intrabony defect depth in the Osteogen® group from 2.54 ± 0.786 to 1.01 ± 0.448 mm, whereas in the Ostim® group, it was 2.71 ± 0.650 mm to 1.12 ± 0.563 mm. Conclusion: It was concluded that both the HA bone grafts produced statistically significant reduction in pocket depth, in the depth of osseous lesion, and a statistically significant gain in attachment level, irrespective of their physico-chemical properties.

  3. Device-quality Intrinsic Microcrystalline Silicon Prepared by 13.56MHz PECVD at High Pressure%高压13.56MHz PECVD法沉积器件质量级本征微晶硅材料

    Institute of Scientific and Technical Information of China (English)

    侯国付; 李以钢; 郭群超; 王岩; 薛俊明; 任慧志; 宋建; 张晓丹; 赵颖; 耿新华

    2005-01-01

    In this paper intrinsic hydrogenated microcrystalline silicon (μc-Si: H) thin films and solar cells prepared by radio-frequency plasma-enhanced chemical vapor deposition (RF-PECVD) method at high pressure are reported. Our experimental results demonstrated that either increasing plasma power or decreasing silane concentration always can lead to structural transition from amorphous silicon to microcrystalline silicon, and then the electrical properties changed along with the micro-structural evolution. By optimizing process parameters and using gas purifier, the oxygen concentration was prohibited effectively and then device-qualityμc-Si: H thin films have been got at a relative high deposition rate. Their applications as absorber layers in single-junctionμc-Si: H solar cells with 1.5μm i-layer yielded conversion efficiency of 5.22% without ZnO back reflector and without optimizing p-layer and p/i interface.%本文国内首次报道了采用高压RF-PECVD技术沉积本征微晶硅材料的结果.实验表明,增大等离子体激发功率和减小硅烷浓度都能够使薄膜材料由非晶硅逐渐向微晶硅转变,而结构上的改变使得电学特性也随之改变.通过工艺参数的优化和纯化器的使用,有效地控制了氧的掺杂,在较高的生长速度下得到了器件质量级的本征微晶硅材料.将实验得到的微晶硅作为太阳电池光吸收层,在没有ZnO背电极和没有优化窗口层材料以及p/i界面时,电池的效率达到5.22%,这进一步表明本征微晶硅材料的良好性能.

  4. 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

  5. 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; ...

  6. Microstructure characterisation of freeze linings formed in a copper slag cleaning slag

    Directory of Open Access Journals (Sweden)

    Jansson J.

    2015-01-01

    Full Text Available The initial growth rate of freeze linings on water-cooled elements submerged in molten iron silicate slag is fast. The freeze lining microstructure forming on water cooled steel surface in a high-silica, slag cleaning furnace slag of a direct-to-blister copper smelter is mostly glassy or amorphous. It contains 5-30 μm magnetite crystals, very small and larger copper droplets as well as small magnetite and silicate nuclei embedded in the glassy silica-rich matrix. Chemically the formed freeze linings are more silica-rich than the slag from which they were generated. Magnetite (spinel is the primary phase of the solidifying SCF slag but it does not form a continuous network through the freeze lining. Its strength is given by the intergranular silica-rich phase which initially is glassy or microcrystalline. Due to only partial slag reduction in the SCF process, large magnetite crystals are present in the freeze lining and seem to interact physically with copper droplets.

  7. Multilayer laminar co-extrudate as a novel controlled release dosage form.

    Science.gov (United States)

    Müllers, Katrin C; Wahl, Martin A; Pinto, João F

    2013-07-16

    Design of a new dosage form manufactured by laminar extrusion for oral administration of drugs. Different mixtures of materials (microcrystalline cellulose [MCC], hydroxypropyl methylcellulose [HPMC], lactose [LAC], dicalcium phosphate [DCP], coumarin [COU], propranolol hydrochloride [PRO], water [W]) were prepared prior to laminar extrusion. Mono, bi and tri layer extrudates were manufactured and evaluated for extrudability, drying, water uptake and swelling ability and in vitro characterization of the drug release. Good quality extrudates were manufactured with higher HPMC molecular weight and fraction in formulation at an extrusion rate of 400 mm/min and slow drying (forced air stream), otherwise surface roughness, thickness in-homogeneity, bending and shark skin were present in the extrudates. Swelling of extrudates was dependent on HPMC fraction and molecular weight (60% up to 90% weight gain for low and high polymer chains, respectively) and the presence of either MCC or DCP. The release of drug was dependent on its solubility (PRO>COU), the fraction of HPMC (low>high fractions), the type of diluent (DCP>MCC) and number of layers (1>2>3 layers). By designing the number and type of layers, dosage forms with well-defined release-kinetics can be tailored. The study has shown the ability of the technology of extrusion to manufacture a controlled release dosage form in a continuous fashion.

  8. Production of dosage forms for oral drug delivery by laminar extrusion of wet masses.

    Science.gov (United States)

    Müllers, Katrin C; Wahl, Martin A; Pinto, João F

    2013-08-01

    Laminar extrusion of wet masses was studied as a novel technology for the production of dosage forms for oral drug delivery. Extrusion was carried out with a ram extruder. Formulations contained either microcrystalline cellulose (MCC) or dicalcium phosphate (DCP) as diluent, hydroxypropyl methylcellulose (HPMC), lactose, and water. Extrudates were characterized for their tensile strength, Young's modulus of elasticity, water absorption, gel forming capacity, and release of two model drugs, coumarin (COU) and propranolol hydrochloride (PRO). Cohesive extrudates could be produced with both filling materials (MCC and DCP) when HPMC was included as a binder at low amounts (3.3-4.5% w/w dry weight). Employing more HPMC, the elasticity of the wet masses increased which resulted in distinct surface defects. For MCC, the maximum HPMC amount that could be included in the formulations (15% w/w dry weight) did not affect the mechanical properties or decrease the drug release significantly. For DCP extrudates, the maximally effective HPMC amount was 30% (w/w dry weight) with influence on both the mechanical properties and drug release. This study suggests that laminar extrusion of wet masses is a feasible technique for the production of dosage forms for oral drug delivery.

  9. A comparative study of the dissolution characteristics of capsule and tablet dosage forms of melt granulations of paracetamol--diluent effects.

    Science.gov (United States)

    Uhumwangho, Michael U; Okor, Roland S

    2007-01-01

    The dissolution characteristics of melt granulations of paracetamol in capsule and tablet dosage form were compared to determine whether the dissolution characteristics of the granules can be actualized by formulating them as rapidly disintegrating tablets. The term melt granulation refers here to the wax-matrix granules that were formed by triturating the drug powder (paracetamol) with a melted carnauba wax. The matrix granules were admixed with diluents (lactose, alpha-cellulose or microcrystalline cellulose) also in granular form to prevent size separation during encapsulation or tableting. The granules were filled into hard gelatin capsules (mean content weight, 500 +/- 6.2 mg) or tableted (mean weight 500 +/- 5.1 mg, and tensile strength 1.36 +/- 0.2 to 1.7 +/- 0.3 MN/m2). The capsules and tablets were subjected to disintegration and in vitro dissolution tests. The dissolution data were analyzed on the basis of zero, first order rate kinetics and Higuchi square root of time relationship. The results showed that the dissolution profiles were generally consistent with a first order rate kinetics (r = 0.95). The first order dissolution rate constants of capsules and tablets of the matrix granules only (without diluents) were 0.31 +/- 0.02 min(-1) and 0.20 +/- 0.03 min(-1), respectively, indicating faster dissolution from the capsules. Therefore, the dissolution characteristics of the matrix particles were not intact after tableting. Addition of diluents to the capsule formulations had no effect on dissolution rates, whereas in the tablets, dissolution rates increased. For instance, inclusion of a diluent up to 50% w/w in the tablets increased the dissolution rate constants to 0.34 +/- 0.04 min(-1) (lactose), 0.42 +/- 0.02 min(-1) (alpha-cellulose), and 0.46 +/- 0.03 min(-1) (microcrystalline cellulose). Thus, alpha-cellulose and microcrystalline cellulose produced greater enhancer effect on the tablet dissolution rates compared to lactose. Both the capsules and

  10. 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

  11. 微晶纤维素在食品工业中的应用研究进展%Research Development of the Application of Microcrystalline Cellulose in Food Industry

    Institute of Scientific and Technical Information of China (English)

    陆红佳; 郑龙辉; 刘雄

    2011-01-01

    微晶纤维素是由天然纤维素经水解至极限聚合度得到的白色粉末状物质,具有特殊的理化性质,被广泛的应用于化工、医药、食品等行业.文中主要综述了微晶纤维素的理化性质及其在食品工业中的应用,并对其发展前景进行了展望.%Microcrystalline cellulose(MCC) is produced by acid hydrolysis of natural cellulose to a level off degrees of polymerization(LODP).It had wide applications in food, pharmaceuticals, and other industries.This paper mainly reviews its physicochemical properties, its application in food industry, and the prospect of its future development.It also provides theoretical references for researchers for further in-depth study.

  12. The Corrosion and Wear Performance of Microcrystalline WC-10Co-4Cr and Near-Nanocrystalline WC-17Co High Velocity Oxy-Fuel Sprayed Coatings on Steel Substrate

    Science.gov (United States)

    Saha, Gobinda C.; Khan, Tahir I.

    2010-11-01

    The study of near-nanocrystalline cermet composite coating was performed by depositing near-nanocrystalline WC-17Co powder using the high velocity oxy-fuel spraying technique. The WC-17Co powder consists of a core with an engineered near-nano-scale WC dispersion with a mean grain size 427 nm. The powder particle contains 6 wt pct of the ductile phase Co matrix mixed into the core to ensure that the reinforcing ceramic phase WC material is discontinuous to limit debridement during wear, while the remainder of the binding phase (11 wt pct) is applied as a coating on the powder particle to improve the ductility. The tribological properties of the coating, in terms of corrosion resistance, microhardness, and sliding abrasive wear, were studied and compared with those of an industrially standard microcrystalline WC-10Co-4Cr coating with a WC mean grain size 3 μm. Results indicated that the WC-17Co coating had superior wear and corrosion resistance compared to the WC-10Co-4Cr coating. The engineered WC-17Co powder with a duplex Co layer had prevented significant decarburization of the WC dispersion in the coating, thereby reducing the intersplat microporosity necessary for initiating microgalvanic cells. The improved wear resistance was attributed to the higher hardness value of the near-nanocrystalline WC-17Co coating.

  13. Microcrystalline cellulose based matrix solid phase dispersion microextration for isomeric triterpenoid acids in loquat leaves by ultrahigh-performance liquid chromatography and quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Cao, Jun; Peng, Li-Qing; Xu, Jing-Jing

    2016-11-11

    An analytical procedure based on matrix solid phase dispersion (MSPD) microextration and ultrahigh-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry was developed for the determination of isomeric triterpenoid acids (maslinic acid, corosolic acid, oleanolic acid and ursolic acid) in loquat leaves. Microcrystalline cellulose was used for the first time as a solid sorbent in MSPD microextration. Compared with the traditional extraction methods, the proposed method possessed the advantages of shorter extraction time, and lower consumption of sample, sorbent and organic solvent. The MSPD parameters that influenced the extraction efficiency of isomeric analytes were investigated and optimized in detail. Under the optimized conditions, good linearity was obtained with correlation coefficients higher than 0.9990. The limits of detection and quantification were 19.6-51.6μg/kg and 65.3-171.8μg/kg, respectively. Meanwhile, the recoveries obtained for all the analytes were ranging from 90.1% to 107.5%. Finally, the optimized method was successfully applied for analyzing these isomeric acids in loquat leaves samples obtained from different cultivated areas.

  14. A terahertz time-domain study on the estimation of opto-mechanical properties of pharmaceutical tablets using the Hashin-Shtrikman bounds for refractive index: a case study of microcrystalline cellulose and starch acetate compacts

    Science.gov (United States)

    Bawuah, Prince; Peiponen, Kai-Erik

    2016-06-01

    This work highlights the use of Hashin-Shtrikman (H-S) bounds in the prediction and verification of the effective refractive index, the height and the Young's modulus of given training sets of pharmaceutical compacts using the measured time delay of a THz pulse traversing the compacts. Set A consisted of 13 microcrystalline cellulose (MCC) compacts whereas set B was made up of 5 starch acetate (SA) compacts. MCC is a typical ingredient of many pharmaceutical tablets. In the case of the MCC compacts, tight and closely matched bounds were obtained between the experimental, the calculated upper, lower bound values for the effective refractive index, and the height values. This promising outcome has shown the high possibility of utilizing H-S bounds in the verification and prediction of the decision level of useful parameters, which can serve as a quality check for pharmaceutical tablets. For the SA compacts, although less tight bounds were observed, the experimental values for the effective refractive index and the Young's modulus were closely matched with the upper and the lower bounds, respectively. We therefore speculate based on the above observations that the MCC tablets contain an almost evenly distributed spherically shaped air voids whereas in the SA compacts, this assumption might not necessary be true.

  15. The synthesis and luminescence of YP {sub x}V{sub 1-x}O{sub 4}:Dy{sup 3+} microcrystalline phosphors by in situ co-precipitation composition of hybrid precursors

    Energy Technology Data Exchange (ETDEWEB)

    Su Xueqing [Department of Chemistry, Tongji University, Shanghai 200092 (China); Yan Bing [Department of Chemistry, Tongji University, Shanghai 200092 (China)]. E-mail: byan@tongji.edu.cn

    2005-10-15

    Dy{sup 3+} activated YP {sub x}V{sub 1-x}O{sub 4} phosphors were synthesized via an in situ chemical co-precipitation process with fixed Dy{sup 3+} concentration (2 mol%) and varying x (x = 0.2, 0.3, 0.4, 0.6, 0.7, 0.8, respectively). In order to obtain the hybrid precursors, the rare earth coordination polymers with salicylic acid were used as precursors and the polyethylene glycol (PEG) was used as dispersing media. Their microstructure and micromorphology have been analyzed by X-ray powder diffraction (XRD) and scanning electronic microscope (SEM), which indicates that there exist some novel cobblestone-like microcrystalline particles. The characteristic transitions of Dy{sup 3+} due to {sup 4}F{sub 9/2} {yields} {sup 6}H{sub 15/2} (blue) and {sup 4}F{sub 9/2} {yields} {sup 6}H{sub 13/2} (yellow) were detected in the emission spectra and the yellow-to-blue intensity ratio decreased with the increase of x value.

  16. Fornemmelse for form

    DEFF Research Database (Denmark)

    Skude, Flemming

    2002-01-01

    Om den arkitektoniske forms afhængighed af aerodynamik, solens nedbrydning og optimering af materialers holdbarhed.......Om den arkitektoniske forms afhængighed af aerodynamik, solens nedbrydning og optimering af materialers holdbarhed....

  17. 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 ...

  18. 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...

  19. Forms in Space.

    Science.gov (United States)

    Moore, Paula

    1998-01-01

    Uses the work of M. C. Escher to instruct upper elementary students in the transformation of flat shape into three-dimensional form. Outlines the lesson as a series of sections: (1) reviewing form drawing; (2) creating three-dimensional effects; (3) imagining the forms in an inhabited world; and (4) using color and shading. (DSK)

  20. Mesonic Form Factors

    Energy Technology Data Exchange (ETDEWEB)

    Frederic D. R. Bonnet; Robert G. Edwards; George T. Fleming; Randal Lewis; David Richards

    2003-07-22

    We have started a program to compute the electromagnetic form factors of mesons. We discuss the techniques used to compute the pion form factor and present preliminary results computed with domain wall valence fermions on MILC asqtad lattices, as well as Wilson fermions on quenched lattices. These methods can easily be extended to rho-to-gamma-pi transition form factors.

  1. Development and evaluation of modified release wax matrix tablet dosage form for tramadol hydrochloride

    Directory of Open Access Journals (Sweden)

    Paresh Ramesh Mahaparale

    2015-01-01

    Full Text Available The objective of this study was to develop modified release dosage forms of tramadol hydrochloride using wax matrix system by melt granulation method. The effect of various waxes, concentration of waxes, effect of excipients on the release profile of drug from wax matrix system was studied. Release retardant effect was observed in the order of hydrogenated vegetable oil (HVO > compritol >precirol. This may be due to more lipophilicity imparted by HVO than any other waxy substances. It was also observed that as ratio of drug: Wax was increased, it sustained release of drug for more time. This may be due to proper embedment/entrapment of drug in sufficient wax matrix system. In case of excipients, release retardant effect was found in order of dicalcium phosphate (DCP > microcrystalline cellulose (MCC > lactose. DCP is insoluble which helps in release retardation of drug. MCC is hydrophilic swellable polymer which showed release of drug by swelling. Lactose is soluble excipient which get dissolved and formed channels for entry of dissolution medium and release of drug occurred by erosion mechanism. Wax matrix tablets were found to be stable.

  2. 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...

  3. 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...

  4. Forming of superplastic ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Lesuer, D.R.; Wadsworth, J.; Nieh, T.G.

    1994-05-01

    Superplasticity in ceramics has now advanced to the stage that technologically viable superplastic deformation processing can be performed. In this paper, examples of superplastic forming and diffusion bonding of ceramic components are given. Recent work in biaxial gas-pressure forming of several ceramics is provided. These include yttria-stabilized, tetragonal zirconia (YTZP), a 20% alumina/YTZP composite, and silicon. In addition, the concurrent superplastic forming and diffusion bonding of a hybrid ceramic-metal structure are presented. These forming processes offer technological advantages of greater dimensional control and increased variety and complexity of shapes than is possible with conventional ceramic shaping technology.

  5. Electronic Capitalization Asset Form

    Data.gov (United States)

    Department of Transportation — National Automated Capitalization Authorization Form used by ATO Engineering Services, Logistics, Accounting for the purpose of identifying and capturing FAA project...

  6. 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.

  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. PowerForms

    DEFF Research Database (Denmark)

    Brabrand, Claus; Møller, Anders; Ricky, Mikkel

    2000-01-01

    All uses of HTML forms may benefit from validation of the specified input field values. Simple validation matches individual values against specified formats, while more advanced validation may involve interdependencies of form fields. There is currently no standard for specifying or implementing...

  9. 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.

  10. 高亮度金刚石薄膜场发射荧光管的制作%The Implementation of High Brightness Field Emission Display of Globe-like Diamond Microcrystalline-aggregate Films

    Institute of Scientific and Technical Information of China (English)

    高金海; 李桢; 张武勤; 张兵临

    2013-01-01

    利用微波等离子化学气相沉积法,制备出类球状微米金刚石聚晶薄膜作为场发射阴极材料.通过采用低熔点玻璃粉烧结工艺,从器件封装、器件烧结、器件排气和器件烤消等方面进行了探索和创新,实现了场致发射荧光管的高真空封装.综合采用这套技术,已经研发出的真空场致发射荧光管,在5.45 V/μm电场下,光的亮度达到了11 000 cd/m2.为将来设计制作矩阵寻址场发射平板显示器件奠定了基础.%Field emission display is a new vacuum flat panel display device. The globe-like diamond microcrystalline-aggregates, as a field emission cathode, were fabricated by microwave plasma chemical vapor deposition (MPCVD). Through the use of low temperature melting glass powder sintering process,and innovations in the device package, sintering, consuming such as exhaust and baking exploration, the field emission display of high vacuum package is implemented. Integrated use of this technology has led to a secondary structure, three-pole structure of the field emission display,obtained in 5. 45 V/μm field, and the light intensity of the samples reached 11 000 cd/m2 This consolidates a strong base for the future design of field emission flat panel display of matrix addressing.

  11. Preparation of 5-HMF directly from microcrystalline cellulose in ionic liquid system%在离子液体体系中由微晶纤维素直接制得5-羟甲基糠醛

    Institute of Scientific and Technical Information of China (English)

    杨伟伟; 王少君

    2012-01-01

    Process of microcrystalline cellulose(MC) dehydration to 5-hydroxymethyl-furaldehyde(5-HMF) using [Bmim][Cl] as solvent and acid ionic liquid [Bmim][HSO4] and CrCl3 as catalysts was studied. The effect of the temperature, reaction time,catalyst content, water content were investigated respectively. When [BmimJ[Cl] content is 4 g, MC content is 0.02 g, adding [Bmim][HSO4] content is 1 g and CrCl3 content is 0. 4 g at 130 ℃ , reaction time 4 h at normal conditions the molar ratio of 5-HMF is 37%. Experimental results demonstrate that the reaction system is active for the dehydration of MC into HMF under mild conditions.%研究了以自制的离子液体[Bmim][CI]为溶剂,酸性离子液体[Bmim-][HSO4]和CrCI3为催化剂,催化微晶纤维素脱水制备5-羟甲基糠醛的过程.分别考察了温度、时间、催化剂量、水含量对反应的影响.反应的优化条件为:常压下,[Bmim][CI]用量为4 g,微晶纤维素为0.02 g,在130℃下加入1 g[Bmim][HSO4]和0.4 g CrCI3,不加水,反应4h,5-HMF的摩尔收率可以达到37%.结果表明,在较温和的离子液体体系中直接转化微晶纤维素制得5-HMF是可行的.

  12. Spin forming development

    Science.gov (United States)

    Gates, W. G.

    1982-05-01

    Bendix product applications require the capability of fabricating heavy gage, high strength materials. Five commercial sources have been identified that have the capability of spin forming metal thicknesses greater than 9.5 mm and four equipment manufacturers produce machines with this capability. Twelve assemblies selected as candidates for spin forming applications require spin forming of titanium, 250 maraging steel, 17-4 pH stainless steel, Nitronic 40 steel, 304 L stainless steel, and 6061 aluminum. Twelve parts have been cold spin formed from a 250 maraging steel 8.1 mm wall thickness machine preform, and six have been hot spin formed directly from 31.8-mm-thick flat plate. Thirty-three Ti-6Al-4V titanium alloy parts and 26 17-4 pH stainless steel parts have been hot spin formed directly from 31.8-mm-thick plate. Hot spin forming directly from plate has demonstrated the feasibility and favorable economics of this fabrication technique for Bendix applications.

  13. Laser assisted forming techniques

    Science.gov (United States)

    Kratky, Alexander

    2007-05-01

    During forming processes high deformations rates can lead to cracks and rupture very easily. Especially brittle materials like titanium or magnesium make difficulties in forming. Due to the dependence of the yield strength on temperature, forming at elevated temperatures eases processing of such materials. Since forming takes place only at localized areas of the work piece selective heating is suffcient and advantageous in most cases. Selective Laser heating offers a possibility to heat only the areas of the work piece where strongest deformations are required. For this purpose several laser sources have been tested like CO II, Diode and Nd:YAG Lasers and their advantages and disadvantages in localized heating of the work pieces will be discussed. The work presented here summarizes research activities at the Institute for Forming and High Power Laser Technology, Vienna University of Technology, on laser assisted deep drawing, laser assisted bending, wire drawing and so on during the last decade. Recent developments like roll profiling, incremental forming processes and hydro forming are discussed briefly.

  14. Circle of Form

    DEFF Research Database (Denmark)

    Jaeger, Thomas Arvid

    2012-01-01

    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...... by this model, and using the knowledge gathered from the other areas, especially perception psychology, it showed to be a possible way to organize contrasts in form, a system of 4 different opposites, geometric, organic, mass and structure: The Circle of Form....

  15. Forms of matter and forms of radiation

    CERN Document Server

    Kleman, Maurice

    2009-01-01

    The theory of defects in ordered and ill-ordered media is a well-advanced part of condensed matter physics. Concepts developed in this field also occur in the study of spacetime singularities, namely: i)- the topological theory of quantized defects (Kibble's cosmic strings) and ii)- the Volterra process for continuous defects, used to classify the Poincar\\'e symmetry breakings. We reassess the classification of Minkowski spacetime defects in the same theoretical frame, starting from the conjecture that these defects fall into two classes, as on they relate to massive particles or to radiation. This we justify on the empirical evidence of the Hubble's expansion. We introduce timelike and null congruences of geodesics treated as ordered media, viz. 'm'-crystals of massive particles and 'r'-crystals of massless particles, with parallel 4-momenta in M^4. Classifying their defects (or 'forms') we find (i) 'm'- and 'r'- Volterra continuous line defects and (ii) quantized topologically stable 'r'-defects, these latt...

  16. Geological Significance of Microcrystalline Morphology and Composition of Framboids Pyrite: A Case Study of Marl of Chihsia Formation%草莓状黄铁矿微晶形态和成分的地质意义——以栖霞组含泥灰岩为例

    Institute of Scientific and Technical Information of China (English)

    李洪星; 陆现彩; 边立曾; 马野牧; 张雪芬; 张壮志; 丁子建

    2012-01-01

    在湖北省京山县雁门口地区二叠世栖霞组上部的含泥灰岩中发现棘皮动物化石,其腔被不同形态微晶的草莓状黄铁矿充填,有正四面体、正六面体、五角十二面体和近球体。溶解氧与草莓状黄铁矿的形成过程有关,其浓度决定微晶的S/Fe。统计显示,黄铁矿的S/Fe平均值随微晶的边数增加而增加,所以,棘皮动物腔内草莓状黄铁矿形成由早及晚的次序为:近球体微晶,五角十二面体微晶,正六面体微晶,正四面体微晶的草莓状黄铁矿。同一环境中,黄铁矿微晶的S/Fe可用来指示形成次序。%Echinoderms fossils were discovered in the Permian marl of Chihsia Formation in Jingshan County,Hubei Province,and the cavity of these echinoderms were filled by framboids pyrite.Different kinds microcrystalline morphology of framboids pyrite are tetrahedron,hexahedron,pentagonal dodecahedron and spherical-like.The S/Fe of pyrite microcrystalline increases with increasing number of edges,from which we determine the time of formation order of framboids pyrite microcrystalline in the cavity of echinoderms is: spherical-like,pentagonal dodecahedron,hexahedron and tetrahedron.In same environment,the S/Fe of pyrite microcrystals can be used to indicate the formation order.

  17. 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.

  18. Transplant Center Search Form

    Science.gov (United States)

    ... Share Your Story Give Us Feedback - A + A Transplant Center Search Form Welcome to the Blood & Marrow ... transplant centers for patients with a particular disease. Transplant Center login Username: * Password: * Request new password Join ...

  19. 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...

  20. Fannish form and content

    Directory of Open Access Journals (Sweden)

    TWC Editor

    2014-09-01

    Full Text Available This issue showcases a variety of investigations into a myriad of platforms, featuring several essays that switch the focus from content to form and illustrate the importance of a range of different fan engagements.

  1. 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 processed...

  2. 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.

  3. 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

  4. 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....

  5. form-Z

    DEFF Research Database (Denmark)

    Jensen, Henrik

    2002-01-01

    Kompendiet gennemgår 3d-modellering, lyssætning og rendering med form-Z. Kurset er opbygget over CAD Clasic skabelonen (se min forskning). Kompendiet kan bruges til selvstudie.......Kompendiet gennemgår 3d-modellering, lyssætning og rendering med form-Z. Kurset er opbygget over CAD Clasic skabelonen (se min forskning). Kompendiet kan bruges til selvstudie....

  6. Achieving form in autobiography

    Directory of Open Access Journals (Sweden)

    Nicholas (Nick Meihuizen

    2014-06-01

    Full Text Available This article argues that, unlike biographies which tend to follow patterns based on conventional expectations, salient autobiographies achieve forms unique to themselves. The article draws on ideas from contemporary formalists such as Peter McDonald and Angela Leighton but also considers ideas on significant form stemming from earlier writers and critics such as P.N. Furbank and Willa Cather. In extracting from these writers the elements of what they consider comprise achieved form, the article does not seek to provide a rigid means of objectively testing the formal attributes of a piece of writing. It rather offers qualitative reminders of the need to be alert to the importance of form, even if the precise nature of this importance is not possible to define. Form is involved in meaning, and this continuously opens up possibilities regarding the reader’s relationship with the work in question. French genetic critic Debray Genette distinguishes between ‘semantic effect’ (the direct telling involved in writing and ‘semiological effect’ (the indirect signification involved. It is the latter, the article argues in summation, which gives a work its singular nature, producing a form that is not predictable but suggestive, imaginative.

  7. 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...

  8. Challenge of paediatric compounding to solid dosage forms sachets and hard capsules - Finnish perspective.

    Science.gov (United States)

    Sivén, Mia; Kovanen, Satu; Siirola, Outi; Hepojoki, Tuomas; Isokirmo, Sari; Laihanen, Niina; Eränen, Tiina; Pellinen, Jukka; Juppo, Anne M

    2017-05-01

    The study evaluated the quality of compounded sachets and hard gelatine capsules and their feasibility in paediatric drug administration. Commercial tablets were compounded to sachets and capsules in hospital environment, and the uniformity of content and simulated drug dose were determined. Compounded formulations were successfully obtained for a range of drug substances; dipyridamole, spironolactone, warfarin and sotalol formulations were within acceptable limits for uniformity of content, in most cases. However, some loss of drug was seen. The type and amount of excipients were found to affect uniformity of content; good conformity of capsules was obtained using lactose monohydrate as filler, whereas microcrystalline cellulose was a better choice in sachets. In capsules, content uniformity was obtained for a range of drug doses. If the drug is aimed to be administered through a nasogastric tube, solubility of the drug and excipients should be considered, as they were found to affect the simulated drug dose in administration. Compounded sachets and capsules fulfilled the quality requirements in most cases. In compounding, the choice of excipients should be considered as they can affect conformity of the dosage form or its usability in practice. Quality assurance of compounded formulations should be taken into consideration in hospital pharmacies. © 2016 Royal Pharmaceutical Society.

  9. Compatibility study between ketoprofen and pharmaceutical excipients used in solid dosage forms.

    Science.gov (United States)

    Tiţa, Bogdan; Fuliaş, Adriana; Bandur, Geza; Marian, Eleonora; Tiţa, Dumitru

    2011-09-10

    Thermogravimetry/derivative thermogravimetry (TG/DTG) and differential scanning calorimetry (DSC) techniques were used for assessing the compatibility between ketoprofen (KT) and several excipients as: corn starch, microcrystalline cellulose (PH 101 and PH 102), colloidal silicon dioxide, lactose (monohydrate and anhydre), polyvinylpyrrolidone K30, magnesium stearate and talc, commonly used in the pharmaceutical form. In order to investigate the possible interactions between the components, the thermal curves of KT and each selected excipients were compared with those of their 1:1 (w/w) physical mixtures. For KT, the DSC curves have shown a sharp endothermic peak at 96.8 °C which corresponds to the melting process (literature value: 94-97 °C), respectively the TG curves demonstrated a simple stage of mass loss in the temperature range of 235-400 °C. FT-IR spectroscopy and X-ray powder diffraction (XRPD) were used as complementary techniques to adequately implement and assist in interpretation of the DSC results. On the basis of thermal results, a possible interaction was found between the KT with polyvinylpyrrolidone K30 and magnesium stearate, which could influence the stability of the KT in the binary mixtures. These possible incompatibilities were confirmed by FT-IR and X-ray analysis.

  10. In situ niosome forming maltodextrin proniosomes of candesartan cilexetil: In vitro and in vivo evaluations.

    Science.gov (United States)

    Yuksel, Nilufer; Bayindir, Zerrin Sezgin; Aksakal, Elif; Ozcelikay, A Tanju

    2016-01-01

    The aim of this study is to develop novel proniosomal tablets of candesartan cilexetil. Drug loaded proniosomes were prepared as dry powder by slurry method. The critical parameters of the production process were the type of the carrier (sorbitol, maltodextrin, and lactose), addition of charge inducers, rotation speed of the rotavapor and solvent evaporation temperature. The effects of these parameters on proniosome specifications such as the recovery, drug loading, drug release were investigated and also the influence on the particle size and surface charge of the niosomes derived by the hydration of proniosomes were evaluated. The mean particle size and drug loading of niosomes formed from the hydrated proniosomes were 204 ± 2 nm and 99.09 ± 0.04% respectively, with a negative charge -43.65 ± 0.54 mV. The proniosomes demonstrated good flowability, compressibility and consolidation properties both alone and together with the tableting agents (microcrystalline cellulose and cross-linked poly vinylpyrrolidone). The niosomes derived by the hydration of proniosomal tablets preserved their initial properties. Compatibly with the increased in vitro drug dissolution rate, the relative bioavailability of drug from proniosomal tablets increased 1.86-fold and 2.75-fold and higher candesartan plasma levels were achieved within shorter time compared to the pure drug.

  11. Photoluminescence of donor-acceptor carbazole-based molecules in amorphous and powder forms

    Science.gov (United States)

    Adès, D.; Boucard, V.; Cloutet, E.; Siove, A.; Olivero, C.; Castex, M. C.; Pichler, G.

    2000-05-01

    We present absorption and photoluminescence features of four samples of carbazole molecules substituted with various electron-acceptor groups. These molecules named 1-(N-ethylcarbazolyl)-2-substituted-2-cyanovinylene contain in their structure the electron-donor carbazole nucleus and cyanovinylene bearing either another nitrile function, an ethylester, a phenyl, or a para-nitrophenyl groups. It is shown that depending on the strength of the donor-acceptor internal charge transfer, both the absorption and emission spectra are more or less redshifted. It is found that the ethyl-ester derivative displays the best relative photoluminescence efficiency among all the samples and its peak is measured at 490 nm when taking amorphous thin film. The microcrystalline powder form of the same material exhibits spectral narrowing and shift of the peak emission. We obtain further narrowing of the emission band and further redshifting of the emission when we illuminate, transversely, a glass capillary containing the crystalline sample by an ultraviolet light-emitting diode.

  12. Quantitative study of formation of free I2 molecules in gamma-irradiated microcrystalline powders of pure and doped potassium iodide

    Science.gov (United States)

    Shirke, A. K.; Band, A. M.; Pode, R. B.; Deshmukh, B. T.

    1993-11-01

    Photodecomposition of pure and doped KI powders [KI:Cs, KI:Rb, KI:Na, KI:CI, KI:Br, KI:RbCl, KI:RbBr, KI:NaCl, impurity concentration 500 p.p.m.] to produce free I2 molecules during gamma irradiation is studied quantitatively by finding G values with the help of absorption measurements and calibration plots. Absorption measurements are made on solutions of irradiated powders after being dissolved in distilled water. G-value or Radiation chemical yield is the fundamental quantitative characteristic of radiation induced chemical change and it is defined as number of ions, free radicals, atoms or molecules formed or destroyed when the system has absorbed 100 eV of energy. G(I2) {Rate of formation of free I2 molecules} for anion doped KI powder [KI:CI, KI:Br] is more compared to pure KI powder. G(I2) for cation doped KI powder [KI:Rb, KI:Cs, KI:Na] is less compared to pure KI powder. Comparatively, G(I2) values obtained are small in KI:RbCl, KI:RbBr and KI:NaCl where both cation and anion are different from the host. These results are explained on the basis of misfit between impurity ions and host ions (difference between ionic radii of impurity ions and host ions). As misfit increases, G(I2) increases in cation doped powders where as in anion doped powders, G(I2) increases with the decrease in misfit.

  13. Comparative waste forms study

    Energy Technology Data Exchange (ETDEWEB)

    Wald, J.W.; Lokken, R.O.; Shade, J.W.; Rusin, J.M.

    1980-12-01

    A number of alternative process and waste form options exist for the immobilization of nuclear wastes. Although data exists on the characterization of these alternative waste forms, a straightforward comparison of product properties is difficult, due to the lack of standardized testing procedures. The characterization study described in this report involved the application of the same volatility, mechanical strength and leach tests to ten alternative waste forms, to assess product durability. Bulk property, phase analysis and microstructural examination of the simulated products, whose waste loading varied from 5% to 100% was also conducted. The specific waste forms investigated were as follows: Cold Pressed and Sintered PW-9 Calcine; Hot Pressed PW-9 Calcine; Hot Isostatic Pressed PW-9 Calcine; Cold Pressed and Sintered SPC-5B Supercalcine; Hot Isostatic pressed SPC-5B Supercalcine; Sintered PW-9 and 50% Glass Frit; Glass 76-68; Celsian Glass Ceramic; Type II Portland Cement and 10% PW-9 Calcine; and Type II Portland Cement and 10% SPC-5B Supercalcine. Bulk property data were used to calculate and compare the relative quantities of waste form volume produced at a spent fuel processing rate of 5 metric ton uranium/day. This quantity ranged from 3173 L/day (5280 Kg/day) for 10% SPC-5B supercalcine in cement to 83 L/day (294 Kg/day) for 100% calcine. Mechanical strength, volatility, and leach resistance tests provide data related to waste form durability. Glass, glass-ceramic and supercalcine ranked high in waste form durability where as the 100% PW-9 calcine ranked low. All other materials ranked between these two groupings.

  14. Formulation and process design for a solid dosage form containing a spray-dried amorphous dispersion of ibipinabant.

    Science.gov (United States)

    Leane, Michael M; Sinclair, Wayne; Qian, Feng; Haddadin, Raja; Brown, Alan; Tobyn, Mike; Dennis, Andrew B

    2013-01-01

    Amorphous forms of poorly soluble drugs are more frequently being incorporated into solid dispersions for administration and extensive research has led to a reasonable understanding of how these dispersions, although still kinetically unstable, improve stability relative to the pure amorphous form. There remains however a paucity of literature describing the effects on such solid dispersions of subsequent processing into solid dosage forms such as tablets. This paper addresses this area by looking at the effects of the addition of common excipients and different manufacturing routes on the stability of a spray-dried dispersion (SDD) of the cannabinoid CB-1 antagonist, ibipinabant. A marked difference in physical stability of tablets was seen with the different fillers with microcrystalline cellulose (MCC) giving the best stability profile. It was found that minimising the number of compression steps led to improved formulation stability with a direct compression process giving the best results. Increased levels of crystallinity were seen in coated tablets most likely due to the exposure of the amorphous matrix to moisture and heat during the coating process. DSIMS analysis of the SDD particles indicated increased levels of polymer on the surface.

  15. In vitro tolerability of human nasal mucosa: histopathological and scanning electron-microscopic evaluation of nasal forms containing Sandostatin.

    Science.gov (United States)

    de Fraissinette, A; Kolopp, M; Schiller, I; Fricker, G; Gammert, C; Pospischil, A; Vonderscher, J; Richter, F

    1995-10-01

    An in vitro human nasal model was developed as a tool to study the local tolerability of nasal powder forms using excised nasal mucosa in a diffusion chamber. The suitability of this model was tested using Sandostatin (SMS) an octapeptide analog of somatostatin, as a reference drug enhanced by Avicel (microcrystalline cellulose) or lactose (100 mesh). The standard nasal spray vehicle was taken as a harmless control and 1% chenodeoxycholate (CDC) as a harmful control in terms of local tolerability. The extent of peptide permeation was determined by measuring SMS concentration in the receiving chamber. The labeling of SMS was detected by immunoperoxidase staining on cross sections. The local tolerability for all tested forms was assessed by histopathological examination and scanning electron microscopy. The apparent permeation coefficient allowed us to rank the absorption of the tested drug forms as Avicel > spray = lactose > 1%CDC. For all formulations, SMS was detected in the epithelium. No changes of the nasal mucosa could be observed with Avicel, lactose or nasal spray vehicle in the presence or absence of SMS. 1%CDC with or without drug showed an immediate destruction of the nasal epithelium. The validation of this in vitro model using human nasal mucosa will be further discussed as a tool for assessing the local tolerability of intranasally applied test substances.

  16. Forms of Inattentiveness

    DEFF Research Database (Denmark)

    Knudsen, Morten

    2011-01-01

    and kept out of sight in the decision processes by looking at a specific case study involving the construction of a model intended to control, and render transparent, the quality of health services in Denmark. This paper outlines the forms of inattentiveness which make communication blind to information...... that could question the quality model. Five forms of inattentiveness are identified that function as answers to the question of how communication avoids actualizing relevant but also potentially destructive information. This study documents a considerable amount of blindness to potentially relevant themes...... and it points to activities that produce this blindness as they reduce the probability that potentially destructive subjects are actualized. Information is not only something organizations need, but may also be something they protect themselves against. In that case, the forms of inattentiveness may...

  17. Physical forms of MIPs.

    Science.gov (United States)

    Biffis, Andrea; Dvorakova, Gita; Falcimaigne-Cordin, Aude

    2012-01-01

    The current state of the art in the development of methodologies for the preparation of MIPs in predetermined physical forms is critically reviewed, with particular attention being paid to the forms most widely employed in practical applications, such as spherical beads in the micro- to nanometer range, microgels, monoliths, membranes. Although applications of the various MIP physical forms are mentioned, the focus of the paper is mainly on the description of the various preparative methods. The aim is to provide the reader with an overview of the latest achievements in the field, as well as with a mean for critically evaluating the various proposed methodologies towards an envisaged application. The review covers the literature up to early 2010, with special emphasis on the developments of the last 10 years.

  18. 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.

  19. Methods for forming particles

    Science.gov (United States)

    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.

  20. 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 lige...... af hans formstudierne gennem dialog og præsentation af incitamenter. Dialogen om form og læringsrums aktiviteter der var centrale for Lynges pædagogik. Dialogen og formeksperimenter kombineres med opfordringer til at søge inspiration i naturen og videnskabelige udredninger. De tematiske angreb er...

  1. 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

  2. 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...... deformation step to avoid overheating and breakdown of the lubricant....

  3. Geodiversity and land form

    Science.gov (United States)

    Gray, Murray

    2014-05-01

    The Earth's surface has a dynamic and topographically varied natural landscape. In some cases the resulting landforms are given generic names reflecting their form and/or origin, (e.g. sand dunes, eskers, ox-bow lakes) but in many cases the land surface has a more amorphous form and is less easily categorized other than at a landscape scale (e.g. dissected plateau, Chalk downland). Across much of Europe, while the natural vegetation has been removed or radically modified, the natural land form/topography remains in tact. In this context and in terms of geoconservation we ought to be: • allowing the dynamic natural processes that create, carve and modify landscapes to continue to operate; and • retaining natural topographic character and geomorphological authenticity in the face of human actions seeking to remodel the land surface. In this presentation examples of this approach to geoconservation of land form will be given from the UK and other parts of the world. This will include examples of both appropriate and inappropriate topographic modifications.

  4. 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

  5. Supercongruences via modular forms

    CERN Document Server

    Osburn, Robert

    2009-01-01

    We prove two supercongruences for the coefficients of power series expansions in t of modular forms where t is a modular function. As a result, we settle two recent conjectures of Chan, Cooper and Sica. Additionally, we provide a table of supercongruences for numbers which appear in similar power series expansions and in the study of integral solutions of Apery-like differential equations.

  6. Forming of Thermoplastic Composites

    NARCIS (Netherlands)

    Haanappel, S.P.; Sachs, U.; Thije, ten R.H.W.; Rietman, A.D.; Akkerman, R.

    2012-01-01

    Design and production guidelines for UD reinforced thermoplastic composites are highly desirable. Therefore, forming experiments and simulations with a realistic complex shaped product were conducted. Thermoforming experiments with quasi-isotropic UD carbon/PEEK and 8HS woven glass/PPS composites sh

  7. 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,…

  8. 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

  9. eta ' transition form factors

    NARCIS (Netherlands)

    Amo Sanchez, del P.; Raven, H.G.; Snoek, H.; BaBar, Collaboration

    2011-01-01

    eta((')) transition form factors in the momentum-transfer range from 4 to 40 GeV(2). The analysis is based on 469 fb(-1) of integrated luminosity collected at PEP-II with the BABAR detector at e(+)e(-) center-of-mass energies near 10.6 GeV.

  10. Three-form cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Koivisto, Tomi S., E-mail: T.Koivisto@ThPhys.Uni-Heidelberg.d [Institute for Theoretical Physics, University of Heidelberg, 69120 (Germany); Nunes, Nelson J. [Institute for Theoretical Physics, University of Heidelberg, 69120 (Germany)

    2010-03-01

    Cosmology of self-interacting three-forms is investigated. The minimally coupled canonical theory can naturally generate a variety of isotropic background dynamics, including scaling, possibly transient acceleration and phantom crossing. An intuitive picture of the cosmological dynamics is presented employing an effective potential. Numerical solutions and analytical approximations are provided for scenarios which are potentially important for inflation or dark energy.

  11. 微晶蜡含量对17-4PH不锈钢喂料流变性的影响%Effect of microcrystalline wax content on rheological properties of 17-4PH stainless steel feedstock

    Institute of Scientific and Technical Information of China (English)

    杨忠臣; 李笃信; 卢仁伟; 黎正科

    2013-01-01

    研究微晶蜡含量对改进型石蜡基17-4PH不锈钢喂料流变性能的影响,比较4种喂料的综合流变因子大小,对粘结剂与金属粉末的相容性进行观测。采用毛细管流变仪测试喂料的流变性能,用扫描电镜观察喂料的形貌。结果表明:4种喂料均呈假塑性流体,微晶蜡的加入可提高喂料的流变性能,且在温度160℃、剪切速率1000 s-1的条件下,向石蜡中加入质量分数为20%微晶蜡的喂料具有较好的综合流变性能,其综合流变学因子αstv=3.068×10-6。同时,适量微晶蜡的加入有助于提高金属粉末在粘结剂中分散的均匀性。%The effect of the content of microcrystalline wax (MW) on rheological properties of 17-4PH stainless steel feedstock was studied and the comprehensive rheological indexes of four feedstocks were compared. The compatibility of binder and metal powders was observed. The rheological properties of feedstocks were tested by capilary rheological instrument, and the morphologies of feedstocks were observed by SEM. The results show that four feedstocks are pseudoplastic fluid, and adding MW to feedstocks can improve the rheological properties, putting 20% MW into the feedstock can acquire relative good comprehensive rheological properties in the condition of temperature of 160℃, shear rate of 1 000 s-1 and the comprehensive rheological index is 3.068×10-6. Meanwhile, putting MW into the feedstock can improve dispersion of binder and metal powders.

  12. Performance Study about Film of Mercerizing Reguar and Microcrystalline Cellulose in the Ionic Liquids%丝瓜络和微晶纤维素在离子液体中成膜性能研究

    Institute of Scientific and Technical Information of China (English)

    陈梅; 魏莉; 王迎; 赵吉祥

    2011-01-01

    [ Objective] The aim was to study performance about film of mercerizing reguar and mierocrystalline cellulose in the ionic liquids. [Method] Regenerated cellulose film was prepared from mercerizing reguar in 1-butyl, 3-methylimidazolium chloride ionic liquid. Properties and structures of the mercerizing reguar and obtained regenerated cellulose films were investigated by FTIR and polarized light microscopy, then contrasted by microcrystalline cellulose. At last, the performance of film was evaluatied. [Result] The results showed that, 1-butyl, 3-methylimidazolium chloride ionic liquid was good non-derivatizing solvents for mercerizing reguar. Mercerizing reguar and mierocrystalline cellulose were compared, it found that dissolve time and solubility in ionic liquids were serious influenced by the degree of polymerization. [ Conclusion] Cellulose film had a certain hole rate and aperture, could be used in permeation and separation field.%[目的]研究丝瓜络和微晶纤维素在离子液体中成膜性能.[方法]以离子液体[BMIM]Cl为溶剂溶解预处理过的丝瓜络,制得纤维素膜,用红外光谱和偏光显微镜对溶解前后的丝瓜络纤维进行表征,并对纤维素膜作了基本的性能评价.[结果]与微晶纤维素为原料的对比试验表明,[BMIM]Cl是丝瓜络纤维的直接溶剂,溶解过程中没有衍生物生成.原料聚合度的大小严重影响纤维素在离子液体中的溶解时间和溶解度.[结论]制备的纤维素平板膜具备一定的空隙率和孔径,可广泛应用于渗透、分离等领域.

  13. 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.

  14. Tube-Forming Assays.

    Science.gov (United States)

    Brown, Ryan M; Meah, Christopher J; Heath, Victoria L; Styles, Iain B; Bicknell, Roy

    2016-01-01

    Angiogenesis involves the generation of new blood vessels from the existing vasculature and is dependent on many growth factors and signaling events. In vivo angiogenesis is dynamic and complex, meaning assays are commonly utilized to explore specific targets for research into this area. Tube-forming assays offer an excellent overview of the molecular processes in angiogenesis. The Matrigel tube forming assay is a simple-to-implement but powerful tool for identifying biomolecules involved in angiogenesis. A detailed experimental protocol on the implementation of the assay is described in conjunction with an in-depth review of methods that can be applied to the analysis of the tube formation. In addition, an ImageJ plug-in is presented which allows automatic quantification of tube images reducing analysis times while removing user bias and subjectivity.

  15. 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.

  16. Sleep disorders - resistant forms

    OpenAIRE

    Koláčková, Pavla

    2016-01-01

    Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of Biological and Medical Sciences Candidate: Pavla Koláčková Supervisor: Doc. RNDr. Vladimír Semecký, CSc. Name of dissertation: Sleep disorders - resistant forms The diploma thesis is about sleep disorders. Sleep disorders are a global problem, lots of people have these problems. This diploma thesis focuses on American International Classification of Sleep Disorders (ICSD) and its application in clinical practice...

  17. Parking and Urban Form

    OpenAIRE

    Brueckner, Jan K.; Franco, Sofia F.

    2015-01-01

    This paper analyzes the provision of residential parking in a monocentric city, with the ultimate goal of appraising the desirability and effects of regulations such as a minimum-parking requirement (MPR) per dwelling. The analysis considers three different regimes for provision of parking space: surface parking, underground parking, and structural parking, with the latter two regimes involving capital investment either in the form of an underground parking garage or an above-ground parking s...

  18. Nucleon Electromagnetic Form Factors

    Energy Technology Data Exchange (ETDEWEB)

    Kees de Jager

    2004-08-01

    Although nucleons account for nearly all the visible mass in the universe, they have a complicated structure that is still incompletely understood. The first indication that nucleons have an internal structure, was the measurement of the proton magnetic moment by Frisch and Stern (1933) which revealed a large deviation from the value expected for a point-like Dirac particle. The investigation of the spatial structure of the nucleon, resulting in the first quantitative measurement of the proton charge radius, was initiated by the HEPL (Stanford) experiments in the 1950s, for which Hofstadter was awarded the 1961 Nobel prize. The first indication of a non-zero neutron charge distribution was obtained by scattering thermal neutrons off atomic electrons. The recent revival of its experimental study through the operational implementation of novel instrumentation has instigated a strong theoretical interest. Nucleon electro-magnetic form factors (EMFFs) are optimally studied through the exchange of a virtual photon, in elastic electron-nucleon scattering. The momentum transferred to the nucleon by the virtual photon can be selected to probe different scales of the nucleon, from integral properties such as the charge radius to scaling properties of its internal constituents. Polarization instrumentation, polarized beams and targets, and the measurement of the polarization of the recoiling nucleon have been essential in the accurate separation of the charge and magnetic form factors and in studies of the elusive neutron charge form factor.

  19. 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...- file Return; Form 8453-EMP, Employment Tax Declaration for an IRS e- file Return; Form 8879-EMP, IRS...

  20. [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.

  1. 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.

  2. Code Optimization in FORM

    CERN Document Server

    Kuipers, J; Vermaseren, J A M

    2013-01-01

    We describe the implementation of output code optimization in the open source computer algebra system FORM. This implementation is based on recently discovered techniques of Monte Carlo tree search to find efficient multivariate Horner schemes, in combination with other optimization algorithms, such as common subexpression elimination. For systems for which no specific knowledge is provided it performs significantly better than other methods we could compare with. Because the method has a number of free parameters, we also show some methods by which to tune them to different types of problems.

  3. 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.

  4. Bipolar pulse forming line

    Science.gov (United States)

    Rhodes, Mark A.

    2008-10-21

    A bipolar pulse forming transmission line module for linear induction accelerators having first, second, third, fourth, and fifth planar conductors which form an interleaved stack with dielectric layers between the conductors. Each conductor has a first end, and a second end adjacent an acceleration axis. The first and second planar conductors are connected to each other at the second ends, the fourth and fifth planar conductors are connected to each other at the second ends, and the first and fifth planar conductors are connected to each other at the first ends via a shorting plate adjacent the first ends. The third planar conductor is electrically connectable to a high voltage source, and an internal switch functions to short a high voltage from the first end of the third planar conductor to the first end of the fourth planar conductor to produce a bipolar pulse at the acceleration axis with a zero net time integral. Improved access to the switch is enabled by an aperture through the shorting plate and the proximity of the aperture to the switch.

  5. 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.

  6. Le forme del fondo

    Directory of Open Access Journals (Sweden)

    Michel Maffesoli

    2004-12-01

    Full Text Available Non è vero che la natura ha paura del vuoto. Forse addirittura si completa. Il vuoto è anche una modalità dell'essere. È possibile nidificarvisi, avvolgersi pigramente e, così, proteggersi dall'angoscia del tempo che passa. Il vuoto delle apparenze è, in alcuni momenti, una delle forme d'espressione della vita sociale. Oltretutto occorre saperle riconoscere. Certamente, abbiamo tutti un'esistenza personale, ma siamo, ugualmente, i rappresentanti, a volte anche le vittime, di uno "spirito comune", forse anche di un "inconscio collettivo" che si è costituito di secolo in secolo. E, molto spesso, quando crediamo di esprimere le nostre idee, siamo soltanto dei portavoce, comparse di un vasto "theatrum mundi" dalle dimensioni infinite.

  7. ELEMENTAL FORMS OF HOSPITALITY

    Directory of Open Access Journals (Sweden)

    Maximiliano Emanuel Korstanje

    2010-11-01

    Full Text Available Modern studies emphasized on the needs of researching the hospitality as relevant aspects of tourism and hospitality fields. Anyway, these approaches are inextricably intertwined to the industry of tourism and do not take seriously the anthropological and sociological roots of hospitality. In fact, the hotel seems to be a partial sphere of hospitality at all. Under this context, the present paper explores the issue of hospitality enrooted in the political and economic indo-European principle of free-transit which is associated to a much broader origin.  Starting from the premise etymologically hostel and hospital share similar origins, we follow the contributions of J Derrida to determine the elements that formed the hospitality up to date.

  8. Paramodular Cusp Forms

    CERN Document Server

    Poor, Cris

    2009-01-01

    We classify Siegel modular cusp forms of weight two for the paramodular group K(p) for primes p< 600. We find that weight two Hecke eigenforms beyond the Gritsenko lifts correspond to certain abelian varieties defined over the rationals of conductor p. The arithmetic classification is in a companion article by A. Brumer and K. Kramer. The Paramodular Conjecture, supported by these computations and consistent with the Langlands philosophy and the work of H. Yoshida, is a partial extension to degree 2 of the Shimura-Taniyama Conjecture. These nonlift Hecke eigenforms share Euler factors with the corresponding abelian variety $A$ and satisfy congruences modulo \\ell with Gritsenko lifts, whenever $A$ has rational \\ell-torsion.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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

  14. Moon (Form-Origin)

    Science.gov (United States)

    Tsiapas, Elias; Soumelidou, Despina; Tsiapas, Christos

    2017-04-01

    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

  15. 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...

  16. 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...

  17. Les formes du fond

    Directory of Open Access Journals (Sweden)

    Michel Maffesoli

    2004-12-01

    Full Text Available Il n'est pas vrai que la nature a horreur du vide. Peut-être même s'y complait-elle. Le creux est aussi une modalité de l'être. Il est possible de s'y nicher, de s'y lover paresseusement et, ainsi, de se protéger contre l'angoisse du temps qui passe. Le creux des apparences est, à certains moments, une des formes d'expression de la vie sociale. Encore faut-il savoir le reconnaître. Certes, nous avons tous une existence personnelle, mais nous sommes, également, les représentants, parfois même les victimes, d'un "esprit commun", peut-être même d'un "inconscient collectif" qui s'est constitué de siècle en siècle. Et, très souvent, là où nous croyons exprimer nos propres idées, nous ne sommes que les porte-voix, les figurants d'un vaste "theatrum mundi" aux dimensions infinies.

  18. Massive star forming environments

    Science.gov (United States)

    Devine, Kathryn Elizabeth

    2010-12-01

    We present a study of the earliest stages of massive star formation, in which we focus on Infrared Dark Clouds (IRDCs) and young massive clusters. We present Very Large Array spectral line observations of ammonia (NH 3) and CCS toward four IRDCs. The NH3 lines provide diagnostics of the temperature and density structure within IRDCs. Based upon the NH 3 column density, IRDCs have masses of ˜ 103 to 10 4 M⊙ . We detect twenty NH3 clumps within four IRDCs, with radii regions are presented from the Near Infrared Imager (NIRIM) camera on the 3.5 m WIYN telescope. We report J, H, and K' band photometry in the clusters AFGL437, AFGL5180, and AFGL5142 and use these results to probe the stellar populations, extinction, and ages of the clusters. We find that all three clusters suffer significant extinction (AK ˜1), have ages ≤ 5 Myr, and are actively forming stars. We conclude that the properties of these embedded clusters are consistent with their evolving from IRDC clumps.

  19. 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...

  20. 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

  1. Forms of War

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, H. [Asklepios Klinik St. Georg, Roentgenabteilung, Lohmuehlenstrasse 5, 20099 Hamburg (Germany)], E-mail: Hermann.vogel@ak-stgeorg.lbk-hh.de; Bartelt, D. [Asklepios Klinik St. Georg, Roentgenabteilung, Lohmuehlenstrasse 5, 20099 Hamburg (Germany)

    2007-08-15

    Purpose: Under war conditions, employed weapons can be identified on radiographs obtained in X-ray diagnostic. The analysis of such X-ray films allows concluding that there are additional information about the conditions of transport and treatment; it shall be shown that there are X-ray findings which are typical and characteristic for certain forms of warfare. Material and method: The radiograms have been collected during thirty years; they come from hospitals, where war casualties had been treated, and personal collections. Results: The material is selected, because in war X-ray diagnostic will be limited and the interest of the opposing parties influence the access to the material; furthermore the possibilities to publish or to communicate facts and thoughts are different. Citizens of the USA, GB, France, or Israel will have easier access to journals than those of Vietnam, Chad, and Zimbabwe. Under war conditions, poor countries, like North Vietnam may develop own concepts of medical care. There are X-ray findings which are typical or even characteristic for air warfare, guerrilla warfare, gas war, desert warfare, conventional warfare, and annihilation warfare, and city guerrilla warfare/civil war. The examples demonstrate that weapons and the conditions of transport and treatment can be recognized by X-ray findings. The radiogram can be read like a document. Conclusion: In War, there are differences between a treatment and imaging diagnostic in countries, which control the air space and in those who do not. Medical care of the poor, i.e. in countries (in general those opposing the western nations) will hardly be published, and poverty has no advocate.

  2. 本征微晶硅薄膜的结构演变及其对太阳电池光伏性能的影响%The Microstructure Evolution of Intrinsic Microcrystalline Silicon Films and Its Influence on the Photovoltaic Performance of Thin-Film Silicon Solar Cells

    Institute of Scientific and Technical Information of China (English)

    袁育杰; 侯国付; 张建军; 薛俊明; 赵颖; 耿新华

    2008-01-01

    Hydrogenated microcrystalline silicon(μc-Si:H)intrinsic films and solar ceils are prepared by plasma enhanced chemical vapor deposition(PECVD)with various hydrogen dilution ratios.The influence of hydrogen dilution ratios on electrical characteristics is investigated to study the phase transition from amorphous to microcrystalline silicon.During the deposition process,the optical emission spectroscopy(OES)from plasma is recorded and compared with the Raman spectra of the films,by which the microstructure evolution of different H2 dilution ratios and its influence on the performance of μc-Si:H n-i-P solar ceils is investigated.%采用高压射频等离子体增强化学气相沉积(RF-PECVD)方法制备本征硅薄膜和n-i-P结构太阳电池,研究了氢稀释率对本征硅薄膜的电学特性和结构特性的影响.采用光发射谱(OES)和喇曼(Raman)散射光谱研究了处于过渡区的本征硅薄膜的纵向结构演变过程.结果表明:光发射谱和喇曼散射光谱可以作为研究硅薄膜的纵向结构演变有效手段.随着氢稀释率的增加,硅薄膜从非晶相向微晶相过渡时,其纵向结构的改变会严重影响硅薄膜太阳电池的光伏性能.

  3. Cross-beta spine architecture of fibrils formed by the amyloidogenic segment NFGSVQFV of medin from solid-state NMR and X-ray fiber diffraction measurements.

    Science.gov (United States)

    Madine, Jillian; Copland, Alastair; Serpell, Louise C; Middleton, David A

    2009-04-14

    Over 30 polypeptides are known to assemble into highly ordered fibrils associated with pathological disorders known collectively as amyloidoses. Structural studies of short model peptides are beginning to reveal trends in the types of molecular interactions that drive aggregation and stabilize the packing of beta-sheet layers within fibrillar assemblies. This work investigates the molecular architecture of fibrils formed by the peptide AMed42-49 representing residues 42-49 of the 50 amino acid polypeptide medin associated with aortic medial amyloid, the most common form of senile localized amyloid. The peptide aggregates within 2 days to form bundles of microcrystalline-like needles displaying a high degree of order. Fibrils were prepared from peptides containing up to 23 13C labels, and the solid-state nuclear magnetic resonance (SSNMR) method rotational resonance (RR) was used to determine constraints on the distances between selective atomic sites within fibrils. The constraints are consistent with unbroken beta-strands hydrogen bonded in a parallel in-register arrangement within beta-sheets. Further RR measurements identify close (>6.5 A) contacts between residues F43 and V46 and between S45 and V46, which can only occur between beta-sheet layers and which are consistent with two principal models of beta-sheet arrangements. X-ray fiber diffraction from partially aligned fibrils revealed the classical amyloid diffraction pattern, and comparison of patterns calculated from model coordinates with experimental data allowed determination of a consistent molecular model.

  4. The Analysis of Forming Forces in Single Point Incremental Forming

    Directory of Open Access Journals (Sweden)

    Koh Kyung Hee

    2016-01-01

    Full Text Available Incremental forming is a process to produce sheet metal parts in quick. Because there is no need for dedicated dies and molds, this process is less cost and time spent. The purpose of this study is to investigate forming forces in single point incremental forming. Producing a cone frustum of aluminum is tested for forming forces. A dynamometer is used to collect forming forces and analyze them. These forces are compared with cutting forces upon producing same geometrical shapes of experimental parts. The forming forces in Z direction are 40 times larger than the machining forces. A spindle and its axis of a forming machine should be designed enough to withstand the forming forces.

  5. Mycobacterium tuberculosis L-forms

    OpenAIRE

    2011-01-01

    M. tuberculosis L-forms researches done in China during the recent years were reviewed in this article. M. tuberculosis L-forms could be produced spontaneously or induced by isoniazid or D-cyclic serine, that influenced the synthesis of cell walls. Among the acid-fast organisms isolated from the patients, more L-forms were found than vegetative forms. In extrapulmonary tuberculosis, M. tuberculosis disseminated through the blood mainly in L-forms, L-forms could adhere on the surface or harbor...

  6. Form and stability of aluminum hydroxide complexes in dilute solution

    Science.gov (United States)

    Hem, John David; Roberson, Charles Elmer

    1967-01-01

    size and orderliness of the polymeric aggregates and was accompanied by a decrease in the pH of the solution. The kinetic experiments and stoichiometric data for solutions aged for long periods provided a means of determining activities of polymerized aluminum. From these values the solubility product for microcrystalline gibbsite was determined to be 2.24 x 10 -3, and its free energy of formation, -? 272.3 0.4 kcal per mole. Where polymerization was observed, the process did not stop with small polynuclear complexes containing a few aluminum ions, but proceeded with aging until macromolecules or colloidal-sized particles were formed.

  7. 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.

  8. 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 form...

  9. Matryoshka of Special Democratic Forms

    CERN Document Server

    Devchand, Chandrashekar; Weingart, Gregor

    2008-01-01

    Special p-forms are forms which have components \\phi_{\\mu_1...\\mu_p} equal to +1,-1 or 0 in some orthonormal basis. A p-form \\phi\\in \\Lambda^p R^d is called democratic if the set of nonzero components {\\phi_{\\mu_1...\\mu_p}} is symmetric under the transitive action of a subgroup of O(d,Z) on the indices {1,...,d}. Knowledge of these symmetry groups allows us to define mappings of special democratic p-forms in d dimensions to special democratic P-forms in D dimensions for successively higher P \\geq p and D \\geq d. In particular, we display a remarkable nested stucture of special forms including a U(3)-invariant 2-form in six dimensions, a G_2-invariant 3-form in seven dimensions, a Spin(7)-invariant 4-form in eight dimensions and a special democratic 6-form \\Omega in ten dimensions. The latter has the remarkable property that its contraction with one of five distinct bivectors, yields, in the orthogonal eight dimensions, the Spin(7)-invariant 4-form. We discuss various properties of this ten dimensional form.

  10. 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...

  11. 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.

  12. 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...

  13. 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.

  14. 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.``

  15. Forming processes and mechanics of sheet metal forming

    NARCIS (Netherlands)

    Burchitz, I.A.

    2004-01-01

    The report is dealing with the numerical analysis of forming processes. Forming processes is the large group of manufacturing processes used to obtain various product shapes by means of plastic deformations. The report is organized as follows. An overview of the deformation processes and the materia

  16. 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.

  17. 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 ...

  18. Strange nucleon form-factors

    Science.gov (United States)

    Maas, F. E.; Paschke, K. D.

    2017-07-01

    A broad program measuring parity-violation in electron-nuclear scattering has now provided a large set of precision data on the weak-neutral-current form-factors of the proton. Under comparison with well-measured electromagnetic nucleon form-factors, these measurements reveal the role of the strange quark sea on the low-energy interactions of the proton through the strange-quark-flavor vector form-factors. This review will describe the experimental program and the implications of the global data for the strange-quark vector form-factors. We present here a new fit to the world data.

  19. [Pseudotumor form of urinary tuberculosis].

    Science.gov (United States)

    Rabii, Redouane; Moufid, Kamal; Joual, Abdenbi; Maani, Ahmed; Bennani, Saad; el Mrini, Mohamed

    2002-12-01

    Urogenital tuberculosis is an increasingly frequent serious disease. The diagnosis is often delayed due to the marked clinical polymorphism, leading to serious sequelae. The diagnosis of typical forms is easy, but some forms are misleading and can lead to an incorrect diagnosis. The authors report a pseudoneoplastic form of urogenital tuberculosis in a young patient that was initially diagnosed as lymphoma. In the light of this case and a review of the literature, the authors emphasize the diagnostic difficulties of these forms and the treatment modalities.

  20. 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.

  1. 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 and insi...... 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....

  2. System for forming janus particles

    Science.gov (United States)

    Hong, Liang [Midland, MI; Jiang, Shan [Champaign, IL; Granick, Steve [Champaign, IL

    2011-01-25

    The invention is a method of forming Janus particles, that includes forming an emulsion that contains initial particles, a first liquid, and a second liquid; solidifying the first liquid to form a solid that contains at least a portion of the initial particles on a surface of the solid; and treating the exposed particle sides with a first surface modifying agent, to form the Janus particles. Each of the initial particles on the surface has an exposed particle side and a blocked particle side.

  3. 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.

  4. Deposition of thin layers of boron nitrides and hydrogenated microcrystalline silicon assisted by high current direct current arc plasma; Deposition assistee par un plasma a arc a haut courant continu de couches minces de Nitrure de Bore et de Silicium microcristallin hydrogene

    Energy Technology Data Exchange (ETDEWEB)

    Franz, D. [Ecole Polytechnique Federale de Lausanne, Centre de Recherches en Physique des Plasmas (CRPP), CH-1015 Lausanne (Switzerland)

    1999-09-01

    In the frame of this thesis, a high current direct current arc (HCDCA) used for the industrial deposition of diamond, has been adapted to study the deposition of two types of coatings: a) boron nitride, whose cubic phase is similar to diamond, for tribological applications, b) hydrogenated microcrystalline silicon, for applications in the semiconductor fields (flat panel displays, solar cells,...). For the deposition of these coatings, the substrates were placed in the diffusion region of the arc. The substrate heating is mainly due to atomic species recombining on its surface. The deposition temperature, varying from 300 to 900 {sup o}C according to the films deposited, is determined by the substrate position, the arc power and the injected gas fluxes, without the use of any external heating or cooling system. Measurements performed on the arc plasma show that the electronic temperature is around 2 eV (23'000 K) while the gas temperature is lower than 5500 K. Typical electronic densities are in the range of 10{sup 12}-10{sup 1'}3 cm{sup -3}. For the deposition of boron nitride films, different boron precursors were used and a wide parameter range was investigated. The extreme difficulty of synthesising cubic boron nitride films by chemical vapour deposition (CVD) did not allow to stabilize the cubic phase of boron nitride in HCDCA. Coatings resulted in hexagonal or amorphous boron nitride with a chemical composition close to stoichiometric. The presence of hydrogen leads to the deposition of rough and porous films. Negative biasing of the samples, for positive ion bombardment, is commonly used to stabilize the cubic phase. In HCDCA and in our biasing range, only a densification of the films could be observed. A boron nitride deposition plasma study by infrared absorption spectroscopy in a capacitive radio frequency reactor has demonstrated the usefulness of this diagnostic for the understanding of the various chemical reactions which occur in this kind

  5. 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...... cooperating with the plurality of user equipment to decode the received data....

  6. Another Form for LAMBDA Method

    Institute of Scientific and Technical Information of China (English)

    ZHOU Yangmei; LIU Jingnan

    2003-01-01

    The LAMBDA methodthat was proposed by Teunissen is introduced. Then, on the basis of both the back-sequential conditional LS technique and the upper-triangular Cholesky decomposition, another form for LAMBDA method is proposed.This new form for LAMBDA method has the same principle and calculation speed as the traditional LAMBDA method.

  7. A técnica da reflectância difusa aplicada ao estudo da fluorescência de 2,3-naftalimidas n-substituídas com grupos alquila incluídas em b-ciclodextrina e adsorvidas em celulose microcristalina Diffuse reflectance technique applied to a fluorescence study of n-alkyl substituted 2,3-naphthalimides included in b-ciclodextrin and adsorbed in microcrystalline cellulose

    Directory of Open Access Journals (Sweden)

    Luis Filipe Vieira Ferreira

    1999-07-01

    Full Text Available The solution fluorescence of N-alkyl-2,3-naphthalimides (1-4 in polar protic and aprotic solvents was compared to the emission from solid samples resulting from the imide complexation with b-cyclodextrin or adsorption on the surface of microcrystalline cellulose. Solid samples of the inclusion complex 2,3-naphthalimides/b-cyclodextrin show maximum for fluorescence emission significantly different to the observed in methanolic solution. Beside this, a clear effect on the alkyl chain length could be observed for these samples which is probably due to differences in probe location inside the cyclodextrin cavity. The constancy for fluorescence quantum yield and fluorescence lifetime for the imides 1 - 4 adsorbed on microcrystalline cellulose suggests that, independently of the polarity of the solvent used for sample preparation, the probe is preferentially located on the cellulose surface. An increase of fluorescence quantum yield and fluorescence lifetime for solid samples, when compared to the values obtained in solution for the different solvents employed in this study (acetonitrile, methanol and water, is fully in accordance with a decrease of the probe mobility due to inclusion in b-cyclodextrin or to adsorption on cellulose.

  8. 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.

  9. 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

  10. 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

  11. Ni0.6Zn0.4Fe2O4铁氧体纳米晶与微米晶300MHz~2GHz的磁导率比较%Comparison of permeability between Ni0.6Zn0.4Fe2O4 nanocrystalline and microcrystalline in 300 MHz-2 GHz frequency range

    Institute of Scientific and Technical Information of China (English)

    李家明; 伍俊夫; 汪忠柱

    2013-01-01

      用水热法制备了平均晶粒尺寸为40 nm 的Ni0.6Zn0.4Fe2O4铁氧体八面体颗粒,同时采用溶胶-凝胶高温烧结法合成 Ni0.6Zn0.4Fe2O4微米晶颗粒。用矢量网络分析仪测试了铁氧体/石蜡混合材料在300MHz~2GHz频段的复磁导率和复介电常数。实验结果表明Ni0.6Zn0.4Fe2O4铁氧体纳米晶粒样品与微米晶样品相比具有更高的磁导率(实部 rµ′在3.3~1.65之间,磁导率虚部 rµ′在1.1左右)、更大的磁损耗以及更优异的微波吸收特性。%Ni0.6Zn0.4Fe2O4 ferrite octahedral nanoparticles with mean crystallite size of about 40 nm were synthesized via hydrothermal route, and the Ni0.6Zn0.4Fe2O4 microcrystalline particles were also synthesized by sol-gel high temperature sintering method. In 300MHz-2GHz frequency range, the complex permeability and permittivity for Ni0.6Zn0.4Fe2O4/wax composites were measured by vector network analyzer. The results showed that Ni0.6Zn0.4Fe2O4 nanoparticle sample presents higher microwave permeability, magnetic loss tangent and more excellent microwave absorption property than microcrystalline sample.

  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. Nitrogen Forms in Humic Substances

    Institute of Scientific and Technical Information of China (English)

    ZHUOSU-NENG; WENQI-XIAO

    1992-01-01

    In this paper,the nitrogen forms in newly-formed humic substances,including humic acid (HA),fulvic acid (FA) and humic acid in humin (HAI),were studied by using the 15N CP-MAS NMR technique in combination with chemical approaches.Results show that the majority of nitrogen in HA,FA and HAI was in the amide form with some presented as aliphatic and/ or aromatic amines and some as pyrrole type nitrogen,although the contents of nonhydrolyzable nitrogen in them differed greatly from each other (15-55%).

  14. 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

  15. Supergravity actions with integral forms

    Science.gov (United States)

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

    2014-12-01

    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 Poincaré dual of a bosonic manifold embedded into a supermanifold. Finally, using integral forms we provide a proof of Gates' so-called "Ectoplasmic Integration Theorem", relating superfield actions to component actions.

  16. Supergravity Actions with Integral Forms

    CERN Document Server

    Castellani, L; 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 of Gates' so-called "Ectoplasmic Integration Theorem", relating superfield actions to component actions.

  17. Supergravity actions with integral forms

    Directory of Open Access Journals (Sweden)

    L. Castellani

    2014-12-01

    Full Text Available 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 Poincaré dual of a bosonic manifold embedded into a supermanifold. Finally, using integral forms we provide a proof of Gates' so-called “Ectoplasmic Integration Theorem”, relating superfield actions to component actions.

  18. Supergravity actions with integral forms

    Energy Technology Data Exchange (ETDEWEB)

    Castellani, L., E-mail: leonardo.castellani@mfn.unipmn.it [Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale, Viale T. Michel, 11, 15121 Alessandria (Italy); INFN, Sezione di Torino, via P. Giuria 1, 10125 Torino (Italy); Catenacci, R., E-mail: roberto.catenacci@mfn.unipmn.it [Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale, Viale T. Michel, 11, 15121 Alessandria (Italy); Grassi, P.A., E-mail: pietro.grassi@mfn.unipmn.it [Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale, Viale T. Michel, 11, 15121 Alessandria (Italy); INFN, Sezione di Torino, via P. Giuria 1, 10125 Torino (Italy)

    2014-12-15

    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 Poincaré dual of a bosonic manifold embedded into a supermanifold. Finally, using integral forms we provide a proof of Gates' so-called “Ectoplasmic Integration Theorem”, relating superfield actions to component actions.

  19. Multiple forming tools in incremental forming - Influence of the forming strategies on sheet contour

    Science.gov (United States)

    Dang, T.; Tebaay, L. M.; Gies, S.; Tekkaya, A. E.

    2016-10-01

    Single point incremental forming (SPIF) is a well known process which is used for rapid prototyping or for small-quantity production. The feature of this process is the flexible manufacturing of complex hollow shapes with the use of basic equipments. However, this forming process takes very long time. To speed up the process time, multiple forming tools can be used simultaneously. This paper presents the influence of the multiple tools in SPIF on the formed shape. The conventional SPIF with a single tool is taken into account for a comparative analysis. The results in this study showed that the tool arrangements and its distance have a significant effect on the geometrical accuracy. Moreover, it is shown the influence between the vertical step size of the tool and the strain distributions. This knowledge can be used for generation of new forming strategies.

  20. 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.

  1. 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.

  2. 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....

  3. 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...

  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. Methods of forming CIGS films

    Energy Technology Data Exchange (ETDEWEB)

    Mansfield, Lorelle; Ramanathan, Kannan

    2017-09-19

    Methods for forming CIGS films are provided. According to an aspect of the invention, a method of forming a CIGS film includes a precursor step, which includes simultaneously evaporating Cu, In, Ga, Se, and Sb onto a substrate. The Se is incident on the substrate at a rate of at least 20 .ANG./s. The method also includes a selenization step, which includes evaporating Se over the substrate after the precursor step.

  6. Virksomhedens formål

    DEFF Research Database (Denmark)

    Thomsen, Steen

    2009-01-01

    Formålsdiskussionen hører naturligt sammen med overvejelser om virksomhedens identitet og mission. Hvem er vi? Hvad er vores eksistensberettigelse? Hvad er det, vi kan, som andre ikke kan?......Formålsdiskussionen hører naturligt sammen med overvejelser om virksomhedens identitet og mission. Hvem er vi? Hvad er vores eksistensberettigelse? Hvad er det, vi kan, som andre ikke kan?...

  7. Forms of Approximate Radiation Transport

    CERN Document Server

    Brunner, G

    2002-01-01

    Photon radiation transport is described by the Boltzmann equation. Because this equation is difficult to solve, many different approximate forms have been implemented in computer codes. Several of the most common approximations are reviewed, and test problems illustrate the characteristics of each of the approximations. This document is designed as a tutorial so that code users can make an educated choice about which form of approximate radiation transport to use for their particular simulation.

  8. Mechanics of Forming Ring Disks

    Directory of Open Access Journals (Sweden)

    Avakyan R.M.

    2010-12-01

    Full Text Available The analysis of forming ring disk of constant thickness in conditions of large plastic deformations taking into account the interconnected change of effective strain and deformation hardening is carried out. The analytical dependences characterizing the relative size of plastic area are obtained. The interrelation between the initial and final form of a product is established at maximum possible size of internal pressure.

  9. Terra firma-forme dermatosis

    OpenAIRE

    2013-01-01

    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...

  10. Oxidized Form of Creatine Kinase

    Institute of Scientific and Technical Information of China (English)

    王希成; 王帆; 邹晓明; 周海梦

    1994-01-01

    The purified rabbit muscle creatine kinase (R-CK) was previously considered homogeneousand without disulfide bonds.By the method of NR/R two-dimensional diagonal SDS-PAGE,two forms of R-CK,designated respectively "oxidized form" of creatine kinase which contained intrachain disulfide bondsand "reduced form" of creatine kinase which did not have any —S—S— bridges,were for the first time sepa-rated.They were found to be the same in amino acid composition,in subunit molecular Weight and in isoelec-tric point,and were almost identical in enzyme activities.Thus it is hard to isolate one from the other bycommon biochemical methods.More extensive studies show that the oxidized form of CK also contains a pair of reactive thiol groupswhich are essential to the enzyme activity,and it has one intrachain disulfide bond per subunit.In the nativestate,this —S—S— bond cannot be reduced by DTT,but by treating the reduced form of CK with some ox-idants,these —S—S— bonds can be formed in vitro.Thus it is presumed that the disulfide bonds are cross-linked through the oxidization of two shallowly buried —SH groups.

  11. Low-temperature, high-performance solution-processed metal oxide thin-film transistors formed by a ‘sol–gel on chip’ process.

    Science.gov (United States)

    Banger, K K; Yamashita, Y; Mori, K; Peterson, R L; Leedham, T; Rickard, J; Sirringhaus, H

    2011-01-01

    At present there is no ‘ideal’ thin-film transistor technology for demanding display applications, such as organic light-emitting diode displays, that allows combining the low-temperature, solution-processability offered by organic semiconductors with the high level of performance achievable with microcrystalline silicon1. N-type amorphous mixed metal oxide semiconductors, such as ternary oxides Mx1My2Oz, where M1 and M2 are metals such as In, Ga, Sn, or Zn, have recently gained momentum because of their high carrier mobility and stability2, 3 and good optical transparency, but they are mostly deposited by sputtering. So far no route is available for forming high-performance mixed oxide materials from solution at low process temperatures <250 °C. Ionic mixed metal oxides should in principle be ideal candidates for solution-processable materials because the conduction band states derived from metal s-orbitals are relatively insensitive to the presence of structural disorder and high charge carrier mobilities are achievable in amorphous structures2. Here we report the formation of amorphous metal oxide semiconducting thin-films using a ‘sol–gel on chip’ hydrolysis approach from soluble metal alkoxide precursors, which affords unprecedented high field-effect mobilities of 10 cm2 V−1 s−1, reproducible and stable turn-on voltages Von≈0 V and high operational stability at maximum process temperatures as low as 230 °C.

  12. 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.

  13. Study on 10 kV/35 Hz Voltage Transformer Based on Extra Microcrystalline Alloy Iron Core%基于超微晶合金铁心的10kV/35Hz电压互感器研究

    Institute of Scientific and Technical Information of China (English)

    谷雷雷; 金钧

    2011-01-01

    当风机水泵系统外部电压频率由50Hz变为35Hz时,50Hz电压互感器出现了饱和问题。针对现有电压互感器测量低频信号出现的问题,设计了10kV/35Hz电压互感器,该互感器以单片机作为测量主体,铁心采用超微晶合金,同时增大铁心截面积,不仅保证了对10kV/35Hz电压和频率参数的测量精度,同样适用于工频环境。%When external voltage frequency of traditional fan motor pump system changes from 50 Hz to 35 Hz, saturated problems take place in 50 Hz voltage transformer. In allusion to existing problems when voltage transformers measure low frequency signals, the 10 kV/35 Hz voltage transformer was designed. The transformer took a single chip microprocessor as measuring main body, iron core adopted extra microcrystalline alloy, and in the meantime iron core cross sectional area was increased. The design not only assures measurement accuracy for 10 kV/35 Hz voltage and frequency parameters, but also is adaptable to that of working frequency environment.

  14. In situ co-precipitation synthesis and luminescence of GdVO{sub 4}: Eu{sup 3+} and Y {sub x}Gd{sub 1-x}VO{sub 4}: Eu{sup 3+} microcrystalline phosphors derived from the assembly of hybrid precursors

    Energy Technology Data Exchange (ETDEWEB)

    Su Xueqing [Department of Chemistry, Tongji University, Siping Road 1239, Shanghai 200092 (China); Yan Bing [Department of Chemistry, Tongji University, Siping Road 1239, Shanghai 200092 (China)]. E-mail: byan@tongji.edu.cn; Huang Honghua [Department of Chemistry, Tongji University, Siping Road 1239, Shanghai 200092 (China)

    2005-08-16

    GdVO{sub 4}: Eu{sup 3+} and Y {sub x}Gd{sub 1-} {sub x}VO{sub 4}: Eu{sup 3+} phosphors have been synthesized by a new wet-chemical method named as in situ co-precipitation from multicomponent hybrid precursors. Their microstructure and micromorphology have been analyzed by X-ray powder diffraction (XRD) and scanning electronic microscope (SEM), which indicates that there exist some novel cobblestone-like microcrystalline particles, especially for GdVO{sub 4}: Eu{sup 3+}. The optical characteristic of Y {sub x}Gd{sub 1-x}VO{sub 4}: Eu{sup 3+} presents that the luminescence intensity reaches the strongest when the molar ratio of Y/Gd is 0.4/0.6 among x = 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, and the phosphor particles show a strong red emission at 618 nm originating from the hypersensitive transition {sup 5}D{sub 0} {yields} {sup 7}F{sub 2} of Eu{sup 3+} ions.

  15. TRASYS form factor matrix normalization

    Science.gov (United States)

    Tsuyuki, Glenn T.

    1992-01-01

    A method has been developed for adjusting a TRASYS enclosure form factor matrix to unity. This approach is not limited to closed geometries, and in fact, it is primarily intended for use with open geometries. The purpose of this approach is to prevent optimistic form factors to space. In this method, nodal form factor sums are calculated within 0.05 of unity using TRASYS, although deviations as large as 0.10 may be acceptable, and then, a process is employed to distribute the difference amongst the nodes. A specific example has been analyzed with this method, and a comparison was performed with a standard approach for calculating radiation conductors. In this comparison, hot and cold case temperatures were determined. Exterior nodes exhibited temperature differences as large as 7 C and 3 C for the hot and cold cases, respectively when compared with the standard approach, while interior nodes demonstrated temperature differences from 0 C to 5 C. These results indicate that temperature predictions can be artificially biased if the form factor computation error is lumped into the individual form factors to space.

  16. Form und Sinn: Sprachwissenschaftliche Betrachtungen (Form and Meaning: Linguistic Observations).

    Science.gov (United States)

    Jakobson, Roman

    This collection of 14 papers and articles by Roman Jakobson contains works written and published between 1931 and 1970 which deal either with global aspects of language or with specific grammatical issues. The collection emphasizes Jakobson's concern for finding the links between form and meaning in language. The text is entirely in German with…

  17. 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…

  18. 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.

  19. Form und Sinn: Sprachwissenschaftliche Betrachtungen (Form and Meaning: Linguistic Observations).

    Science.gov (United States)

    Jakobson, Roman

    This collection of 14 papers and articles by Roman Jakobson contains works written and published between 1931 and 1970 which deal either with global aspects of language or with specific grammatical issues. The collection emphasizes Jakobson's concern for finding the links between form and meaning in language. The text is entirely in German with…

  20. 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...

  1. Methods of forming boron nitride

    Science.gov (United States)

    Trowbridge, Tammy L; Wertsching, Alan K; Pinhero, Patrick J; Crandall, David L

    2015-03-03

    A method of forming a boron nitride. The method comprises contacting a metal article with a monomeric boron-nitrogen compound and converting the monomeric boron-nitrogen compound to a boron nitride. The boron nitride is formed on the same or a different metal article. The monomeric boron-nitrogen compound is borazine, cycloborazane, trimethylcycloborazane, polyborazylene, B-vinylborazine, poly(B-vinylborazine), or combinations thereof. The monomeric boron-nitrogen compound is polymerized to form the boron nitride by exposure to a temperature greater than approximately 100.degree. C. The boron nitride is amorphous boron nitride, hexagonal boron nitride, rhombohedral boron nitride, turbostratic boron nitride, wurzite boron nitride, combinations thereof, or boron nitride and carbon. A method of conditioning a ballistic weapon and a metal article coated with the monomeric boron-nitrogen compound are also disclosed.

  2. Methods of forming boron nitride

    Energy Technology Data Exchange (ETDEWEB)

    Trowbridge, Tammy L; Wertsching, Alan K; Pinhero, Patrick J; Crandall, David L

    2015-03-03

    A method of forming a boron nitride. The method comprises contacting a metal article with a monomeric boron-nitrogen compound and converting the monomeric boron-nitrogen compound to a boron nitride. The boron nitride is formed on the same or a different metal article. The monomeric boron-nitrogen compound is borazine, cycloborazane, trimethylcycloborazane, polyborazylene, B-vinylborazine, poly(B-vinylborazine), or combinations thereof. The monomeric boron-nitrogen compound is polymerized to form the boron nitride by exposure to a temperature greater than approximately 100.degree. C. The boron nitride is amorphous boron nitride, hexagonal boron nitride, rhombohedral boron nitride, turbostratic boron nitride, wurzite boron nitride, combinations thereof, or boron nitride and carbon. A method of conditioning a ballistic weapon and a metal article coated with the monomeric boron-nitrogen compound are also disclosed.

  3. Emerging Forms of Cultural Capital

    DEFF Research Database (Denmark)

    Prieur, Annick; Savage, Mike

    or preferences can be demonstrated, and how the move can be made from observing structured oppositions in cultural consumptions to claims about the existence of cultural capital? We note that current research frequently lack a clear argument about how the cultural forms possessed by the culturally privileged...... Distinction about the significance and content of emerging forms of cultural capital in different Western societies. Among the claims to be discussed are the following: - the claim about a decline in the adherence to traditional highbrow or classic high culture - the claim about increased omnivorousness and...... - 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...

  4. Induction interview form in EDH

    CERN Document Server

    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...

  5. Induction interview form in EDH

    CERN Document Server

    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...

  6. 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.

  7. New directions in Dirichlet forms

    CERN Document Server

    Jost, Jürgen; Mosco, Umberto; Rockner, Michael; Sturm, Karl-Theodor

    1998-01-01

    The theory of Dirichlet forms brings together methods and insights from the calculus of variations, stochastic analysis, partial differential and difference equations, potential theory, Riemannian geometry and more. This book features contributions by leading experts and provides up-to-date, authoritative accounts on exciting developments in the field and on new research perspectives. Topics covered include the following: stochastic analysis on configuration spaces, specifically a mathematically rigorous approach to the stochastic dynamics of Gibbs measures and infinite interacting particle systems; subelliptic PDE, homogenization, and fractals; geometric aspects of Dirichlet forms on metric spaces and function theory on such spaces; generalized harmonic maps as nonlinear analogues of Dirichlet forms, with an emphasis on non-locally compact situations; and a stochastic approach based on Brownian motion to harmonic maps and their regularity. Various new connections between the topics are featured, and it is de...

  8. Auxin biosynthesis and storage forms.

    Science.gov (United States)

    Korasick, David A; Enders, Tara A; Strader, Lucia C

    2013-06-01

    The plant hormone auxin drives plant growth and morphogenesis. The levels and distribution of the active auxin indole-3-acetic acid (IAA) are tightly controlled through synthesis, inactivation, and transport. Many auxin precursors and modified auxin forms, used to regulate auxin homeostasis, have been identified; however, very little is known about the integration of multiple auxin biosynthesis and inactivation pathways. This review discusses the many ways auxin levels are regulated through biosynthesis, storage forms, and inactivation, and the potential roles modified auxins play in regulating the bioactive pool of auxin to affect plant growth and development.

  9. $K_{13}$ transition form factors

    CERN Document Server

    Chueng Ryong Ji

    2001-01-01

    The rainbow truncation of the quark Dyson-Schwinger equation is combined with the ladder Bethe-Salpeter equation for the meson bound state amplitudes and the dressed quark-W vertex in a manifestly covariant calculation of the K/sub l3/ transition form factors and decay width in the impulse approximation. With model gluon parameters previously fixed by the chiral condensate, the pion mass and decay constant, and the kaon mass, our results for the K/sub l3/ form factors and the kaon semileptonic decay width are in good agreement with the experimental data. (37 refs).

  10. Language, Culture and Symbolic Forms

    OpenAIRE

    Theis, Wolfgang

    2010-01-01

    As Ernst Cassierer introduced in his “Philosophie der symbolischen Formen” in 1923, he specifically mentioned “language” as well as a way of symbolic forms. In 1991, the self declared “researcher on human sciences”, Norbert Elias, published his work called “The Symbol Theory” where he mainly writes about language as an application of symbolic forms and symbols. Elias does not make any reference to Cassirer at all, but states that languages are a part of a civilization process and part of cult...

  11. Metallurgical Characterization of Superplastic Forming

    Science.gov (United States)

    1980-09-01

    The trans - formation of constant-crosshead-speed stress-strain curves into constant-strain- rate curves is clearly not satisfactory because it is based...MILL-ANNEALED AND SUPERPLASTICALLY- FORMED CONDITIONS; FORMING TEMPERATURE - 949EPC (17400F). 01"tln Stoi rte yeld grasa Ultimate l to oret~lSri as...1975), p. 163. 7. G. Rai and N. J. Grant, "On the Measurermients of Superplasticity in an Al-Cu Alloy," Met. Trans . 6A, 385 (1975). 8. A. K, Mukherjee

  12. 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

  13. 75 FR 26782 - Agency Information Collection Activities: Form I-864, Form I-864A, Form I-864EZ, and Form I-864W...

    Science.gov (United States)

    2010-05-12

    ... Agency Information Collection Activities: Form I-864, Form I- 864A, Form I-864EZ, and Form I-864W... Collection Under Review; Form I- 864, Affidavit of Support Under Section 213A of the Act; Form I-864A, Contract Between Sponsor and Household Member, Form I-864EZ, Affidavit of Support Under Section 213A of...

  14. Free Form Technology from Delft

    NARCIS (Netherlands)

    Eekhout, A.J.C.M.; Van Gelder, B.L.; Lockefeer, W.A.A.M.; Veltkamp, M.; Vollers, K.J.

    2016-01-01

    The success of the Guggenheim Museum in Bilbao, designed and engineered by Frank O. Gehry and inaugurated in 1997, opened the eyes of the world to the plastic possibilities of Free Form Design. That is, on the side of architects and their admiring clients. Some architects draw up complicated but sur

  15. Temporal form in interaction design

    DEFF Research Database (Denmark)

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

    2015-01-01

    a nuanced account of what temporal form is in interaction design, and we look at related work synthesizing what we already know of the temporal concerns in interaction design and HCI. In the second part we present a design experiment through which we explore the experiential qualities of a set of 11 simple...

  16. 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.

  17. 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...

  18. Temporal form in interaction design

    DEFF Research Database (Denmark)

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

    2015-01-01

    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...

  19. Application of Incremental Sheet Forming

    Directory of Open Access Journals (Sweden)

    Karbowski Krzysztof

    2015-12-01

    Full Text Available This paper describes some manufacturing aspects and an example of application of the Incremental Sheet Forming (ISF technology which was used for production of the craniofacial prosthesis. The brief description of prosthesis designing was presented as well. The main topic of the paper is comparison of milling and ISF technologies for preparing the tools for prosthesis thermoforming.

  20. Multiplicative forms and Spencer operators

    NARCIS (Netherlands)

    Crainic, Marius; Salazar Pinzon, Maria; Struchiner, Ivan

    2014-01-01

    Motivated by our attempt to recast Cartan’s work on Lie pseudogroups in a more global and modern language, we are brought back to the question of understanding the linearization of multiplicative forms on groupoids and the corresponding integrability problem. From this point of view, the novelty of

  1. Spin-forming Project Report

    Energy Technology Data Exchange (ETDEWEB)

    Switzner, Nathan; Henry, Dick

    2009-03-20

    In a second development order, spin-forming equipment was again evaluated using the test shape, a hemispherical shell. In this second development order, pure vanadium and alloy titanium (Ti-6Al-4V) were spin-formed, as well as additional copper and 21-6-9 stainless. In the first development order the following materials had been spin-formed: copper (alloy C11000 ETP), 6061 aluminum, 304L stainless steel, 21-6-9 stainless steel, and tantalum-2.5% tungsten. Significant challenges included properly adjusting the rotations-per-minute (RPM), cracking at un-beveled edges and laser marks, redressing of notches, surface cracking, non-uniform temperature evolution in the titanium, and cracking of the tailstock. Lessons learned were that 300 RPM worked better than 600 RPM for most materials (at the feed rate of 800 mm/min); beveling the edges to lower the stress reduces edge cracking; notches, laser marks, or edge defects in the preform doom the process to cracking and failure; coolant is required for vanadium spin-forming; increasing the number of passes to nine or more eliminates surface cracking for vanadium; titanium develops a hot zone in front of the rollers; and the tailstock should be redesigned to eliminate the cylindrical stress concentrator in the center.

  2. 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.

  3. 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)

  4. 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 haza...

  5. PIC Reading Readiness Test Form.

    Science.gov (United States)

    Short, N. J.

    This rating form concerns the measurement of basic skills in connection with assessing reading readiness. Motor skills, ability to adjust to learning situations, familiarity with the alphabet, and general knowledge are assessed. See TM 001 111 for details of the Regional PIC program in which it is used. (DLG)

  6. Exploration of novel co-processed multifunctional diluent for the development of tablet dosage form

    OpenAIRE

    Gohel, M. C.; Patel, T. M.; Parikh, R. K.; P B Parejiya; Barot, B. S.; A Ramkishan

    2012-01-01

    The aim of this investigation was to develop a novel multifunctional co-processed diluent consisting of microcrystalline cellulose (Avicel PH 102), crospovidone (Polyplasdone XL) and polyethylene glycol 4000. Colloidal silicon dioxide and talc were also incorporated as minor components in the diluent to improve tableting properties. Melt granulation was adopted for preparation of co-processed diluent. Percentage of Avicel PH 102, Polyplasdone XL and polyethylene glycol 4000 were selected as i...

  7. 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.

  8. Unsplit bipolar pulse forming line

    Science.gov (United States)

    Rhodes, Mark A.

    2011-05-24

    A bipolar pulse forming transmission line module and system for linear induction accelerators having first, second, third, and fourth planar conductors which form a sequentially arranged interleaved stack having opposing first and second ends, with dielectric layers between the conductors. The first and second planar conductors are connected to each other at the first end, and the first and fourth planar conductors are connected to each other at the second end via a shorting plate. The third planar conductor is electrically connectable to a high voltage source, and an internal switch functions to short at the first end a high voltage from the third planar conductor to the fourth planar conductor to produce a bipolar pulse at the acceleration axis with a zero net time integral. Improved access to the switch is enabled by an aperture through the shorting plate and the proximity of the aperture to the switch.

  9. 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.

  10. 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.

  11. Form Factors of Few-Body Systems: Point Form Versus Front Form

    CERN Document Server

    Gómez-Rocha, Maria; Schweiger, Wolfgang

    2011-01-01

    We present a relativistic point-form approach for the calculation of electroweak form factors of few-body bound states that leads to results which resemble those obtained within the covariant light-front formalism of Carbonell et al. Our starting points are the physical processes in which such form factors are measured, i.e. electron scattering off the bound state, or the semileptonic weak decay of the bound state. These processes are treated by means of a coupled-channel framework for a Bakamjian-Thomas type mass operator. A current with the correct covariance properties is then derived from the pertinent leading-order electroweak scattering or decay amplitude. As it turns out, the electromagnetic current is affected by unphysical contributions which can be traced back to wrong cluster properties inherent in the Bakamjian-Thomas construction. These spurious contributions, however, can be separated uniquely, as in the covariant light-front approach. In this way we end up with form factors which agree with tho...

  12. Do atmospheric aerosols form glasses?

    OpenAIRE

    Zobrist, B.; Marcolli, C.; Pedernera, D. A.; Koop, T.

    2008-01-01

    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

  13. Superprocesses on Two Space Forms

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Superprocess is one class of measure-valued branching Markov processes. Many results of the process on abstract spaces and Euclidean spaces are obtained in the literature. In this paper, we discuss super-Brownian motions on two space forms and reveal partially the relationship between the properties of superprocesses and the geometric structure of the underlying state spaces. Finally, we also presents some open problems.

  14. SOD FORM OF PERENNIAL GRASSES

    OpenAIRE

    Belyuchenko I. S.

    2014-01-01

    The article considers the peculiarities of turf and sod, specificity of formation of kidneys for regeneration, types of shoots, vegetative mobility and specificity of growth in certain conditions, turf grasses are divided into loosely-and tightly-turf characterized, by specific features of environmental, biological characteristics; forming turf from generative rosettes, elongated and shortened vegetative, side ground shoots, differing specificity of morphological, biochemical and fitocoenotic...

  15. 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.

  16. 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.

  17. Lecture Notes on Differential Forms

    OpenAIRE

    2016-01-01

    This is a series of lecture notes, with embedded problems, aimed at students studying differential topology. Many revered texts, such as Spivak's "Calculus on Manifolds" and Guillemin and Pollack's "Differential Topology" introduce forms by first working through properties of alternating tensors. Unfortunately, many students get bogged down with the whole notion of tensors and never get to the punch lines: Stokes' Theorem, de Rham cohomology, Poincare duality, and the realization of various t...

  18. The integral form of supergravity

    Energy Technology Data Exchange (ETDEWEB)

    Castellani, L. [Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale,Viale T. Michel, 11, 15121 Alessandria (Italy); INFN - Sezione di Torino,via P. Giuria 1, 10125 Torino (Italy); Catenacci, R. [Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale,Viale T. Michel, 11, 15121 Alessandria (Italy); Gruppo Nazionale di Fisica Matematica, INdAM,P.le Aldo Moro 5, 00185 Roma (Italy); Grassi, P.A. [Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale,Viale T. Michel, 11, 15121 Alessandria (Italy); INFN - Sezione di Torino,via P. Giuria 1, 10125 Torino (Italy)

    2016-10-11

    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 rôle of Poincaré 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.

  19. Lie groups and automorphic forms

    CERN Document Server

    Ji, Lizhen; Xu, H W; Yau, Shing-Tung

    2006-01-01

    Lie groups are fundamental objects in mathematics. They occur naturally in differential geometry, algebraic geometry, representation theory, number theory, and other areas. Closely related are arithmetic subgroups, locally symmetric spaces and the spectral theory of automorphic forms. This book consists of five chapters which give comprehensive introductions to Lie groups, Lie algebras, arithmetic groups and reduction theories, cohomology of arithmetic groups, and the Petersson and Kuznetsov trace formulas.

  20. Current forms and gauge invariance

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, M Castrillon [Departemento de GeometrIa y TopologIa, Facultad de Matematicas, Universidad Complutense de Madrid, 28040-Madrid (Spain); Masque, J Munoz [Instituto de FIsica Aplicada, CSIC, C/Serrano 144, 28006-Madrid (Spain)

    2004-05-14

    Let C be the bundle of connections of a principal G-bundle {pi}:P {yields} M, and let V be the vector bundle associated with P by a linear representation G {yields} GL(V) on a finite-dimensional vector space V. The Lagrangians on J{sup 1}(C x {sub M}V) whose current form is gauge invariant, are described and the gauge-invariant Lagrangians on J{sup 1}(V) are classified.

  1. Rib forming tool for tubing

    Science.gov (United States)

    Rowley, James P.; Lewandowski, Edward F.; Groh, Edward F.

    1976-01-01

    Three cylindrical rollers are rotatably mounted equidistant from the center of a hollow tool head on radii spaced 120.degree. apart. Each roller has a thin flange; the three flanges lie in a single plane to form an internal circumferential rib in a rotating tubular workpiece. The tool head has two complementary parts with two rollers in one part of the head and one roller in the other part; the two parts are joined by a hinge. A second hinge, located so the rollers are between the two hinges, connects one of the parts to a tool bar mounted in a lathe tool holder. The axes of rotation of both hinges and all three rollers are parallel. A hole exposing equal portions of the three roller flanges is located in the center of the tool head. The two hinges permit the tool head to be opened and rotated slightly downward, taking the roller flanges out of the path of the workpiece which is supported on both ends and rotated by the lathe. The parts of the tool head are then closed on the workpiece so that the flanges are applied to the workpiece and form the rib. The tool is then relocated for forming of the next rib.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Noncigarette forms of tobacco use.

    Science.gov (United States)

    Viegas, Carlos Alberto de Assis

    2008-12-01

    There are many preparations for tobacco use, which can be classified as smoking or smokeless tobacco. Among the noncigarette preparations that produce smoke, we cite cigars, pipes and narghiles. Smokeless tobacco can be found in preparations for chewing or for being absorbed by nasal and oral mucosae (snuff). However, all tobacco products deliver nicotine to the central nervous system and there is a confirmed risk of dependence. In addition, there is no safe form of tobacco use, and tobacco users have a significantly increased risk of morbidity and premature mortality due to tobacco-related diseases.

  7. 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...... in research presented at a recent working conference, and find that a frequent form of HWID theory may be a combination of a HCI theory, domain-specific theory and theorizing on the relation between empirical work analysis and interaction design. At the end of the paper, we propose some constraints...

  8. 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.

  9. 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.

  10. Emerging Forms of Cultural Capital

    DEFF Research Database (Denmark)

    Prieur, Annick; Savage, Mike

    2013-01-01

    This paper takes stock of recent research on patterns of cultural engagement in various European nations, with specific reference to British and Danish research. It argues that Bourdieu's original theorisation of cultural capital in ‘Distinction’ needs to be significantly updated to register...... the decline of ‘highbrow’ culture which these studies reveal. However, we argue that this shift does not entail the erosion of cultural capital itself, or the rise of the ‘cultural omnivore’, so much as the emergence of a form of ‘cosmopolitan cultural capital’. We argue that this emerging cultural capital...

  11. 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.

  12. 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.

  13. 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.

  14. Screening three-form fields

    Science.gov (United States)

    Barreiro, Tiago; Bertello, Ugo; Nunes, Nelson J.

    2017-10-01

    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.

  15. 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

  16. 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

  17. 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.

  18. Fabrication Aware Form-finding

    DEFF Research Database (Denmark)

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

    2014-01-01

    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......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...

  19. Determination of the Contents of n-and i-Paraffins in Paraffin and Microcrystalline Waxes by Modified Urea Adduction%用改进的尿素络合法测定石蜡、微晶蜡中正异构烷烃含量

    Institute of Scientific and Technical Information of China (English)

    冯玉海; 沈本贤; 陈新; 高晋生

    2001-01-01

    Using the orthoganal design method, the optimum conditions were determined in measuring the contens of n- and i-paraffins in paraffin waxes by urea adduction. The weight of urea is three times of that of waxes, the weight of activating agent is 18% of that of urea, the reaction time is 2h and the reaction temperature is 25°C. The method of measuring the contents of n- and i-paraffins in paraffin waxes by urea adduction under those conditions determined by this paper called modified urea adduction. The results show that the modified urea adduction not only could measure the contents of n- and i-paraffins in paraffin waxes, but also could measure that in microcrystalline waxes and mixed waxes, the numerical data agree well with that measured by GC.%采用正交试验,通过与气相色谱法测定结果进行对照,确定了用改进的尿素络合法测定石蜡的正异构烷烃含量的最佳条件:尿素与石蜡用量之比为3∶1(m/m),活化剂与尿素用量之比为0.18∶1(m/m),反应时间2h,反应温度25°C。实验结果表明,该法不但可以测定石蜡,而且可以测定微晶蜡和混合蜡中正异构烷烃的含量,其结果与色谱法测定基本一致。

  20. 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. 

  1. 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.

  2. Prosodic form and parsing commitments.

    Science.gov (United States)

    Watt, S M; Murray, W S

    1996-03-01

    This paper examines the question of whether there are effects of prosody on the syntactic parsing of temporarily ambiguous sentences containing complement verbs. It reports the results of five experiments employing cross-modal response tasks where the visually presented target word was either an ¿appropriate' or an ¿inappropriate' continuation in terms of the prosodic form of the preceeding auditory sentence fragment. Two experiments employing cross-modal naming only showed indications of sensitivity to syntactic and appropriateness manipulations when coupled with a simultaneous appropriateness judgment task. In contrast, the experiments employing cross-modal lexical decision showed greater sensitivity to syntactic and appropriateness effects. However, while the results from these studies replicated our earlier auditory parsing results and provided support for the suggestion that there are differences in visual and auditory parsing processes and for a ¿constituent-based, ' ¿minimal commitment' type auditory parser, none of the studies demonstrated an effect of prosodic form on the parsing process.

  3. Do atmospheric aerosols form glasses?

    Science.gov (United States)

    Zobrist, B.; Marcolli, C.; Pedernera, D. A.; Koop, T.

    2008-09-01

    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 more hydrophobic organic molecules are more likely to form glasses at intermediate to high relative humidities in the upper troposphere

  4. 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

  5. Do atmospheric aerosols form glasses?

    Directory of Open Access Journals (Sweden)

    B. Zobrist

    2008-05-01

    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 bisulphate and mixtures of dicarboxylic acids (M5, of dicarboxylic acids and ammonium sulphate (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 and more hydrophobic organic

  6. Alumina forming iron base superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Yukinori; Muralidharan, Govindarajan; Brady, Michael P.

    2014-08-26

    An austenitic stainless steel alloy, consists essentially of, in weight percent 2.5 to 4 Al; 25 to 35 Ni; 12 to 19 Cr; at least 1, up to 4 total of at least one element selected from the group consisting of Nb and Ta; 0.5 to 3 Ti; less than 0.5 V; 0.1 to 1 of at least on element selected from the group consisting of Zr and Hf; 0.03 to 0.2 C; 0.005 to 0.1 B; and base Fe. The weight percent Fe is greater than the weight percent Ni. The alloy forms an external continuous scale including alumina, and contains coherent precipitates of .gamma.'-Ni.sub.3Al, and a stable essentially single phase FCC austenitic matrix microstructure. The austenitic matrix is essentially delta-ferrite-free and essentially BCC-phase-free.

  7. Innovative forms of citizen participation

    DEFF Research Database (Denmark)

    Nyseth, Torill; Ringholm, Toril; Agger, Annika

    Formal procedures of citizen participation in planning and urban governance in Norway and Denmark share many similarities. Although the planning laws are intended to give all affected stakeholders a chance to air their concerns within a limited time frame, then few use these channels for voice......: What characterises the new and innovative forms of citizen participation in urban planning in terms of innovation? And in what ways and to what degree is input from these processes fed into the formal planning processes? Theoretically, the paper is inspired by the concept of: ‘planning...... interact within the field of urban governance. This is for example seen in urban regeneration projects in Denmark and planning experiments in Norway where we are witnessing more inclusive and bottom-up initiated interactions between public authorities and local actors. The key question in this paper is...

  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......This paper reviews recent European studies to assess whether cultural capital now has the same characteristics – or may be rather the same functions - as when Distinction was written. The paper will examine empirical applications of the concept of cultural capital in leading European studies...... – and hence are highly appropriate for direct comparisons with that study. This paper will begin by raising general issues regarding the meaning of the concept, and about how one may make assessments and claims about cultural capital. Here we consider how the legitimacy of certain cultural competencies...

  9. New marine science organization formed

    Science.gov (United States)

    Wooster, Warren S.

    A new international organization, the North Pacific Marine Science Organization (PICES) will be established to promote and coordinate marine scientific research in the northern North Pacific Ocean and the Berlin Sea. This was decided in Ottawa on December 12, 1990, when a draft convention was approved by representatives of Canada, China, Japan, the United States, and the Soviet Union. PICES will focus on research on the ocean environment and its interactions with land and atmosphere, its role and response to global weather and climate change, its flora, fauna and ecosystems, its uses and resources, and impacts upon it from human activities. Such studies relate not only to the effects of fishing and environmental change on fish stocks but also to such issues as the impacts of oil spills and other forms of pollution and the eventual consequences of climate change for uses of the ocean and its resources.

  10. 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...

  11. The Textile Form of Sound

    DEFF Research Database (Denmark)

    Bendixen, Cecilie

    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...... three-dimensional geometries of interfering spheres are created. Textiles are generally a very good sound dampening material. To dampen the sound most effective it should be placed where the sound energy is highest. To find these invisible spots of energy and to reveal the geometry of them, two...... 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...

  12. Forms and Linear Network Codes

    DEFF Research Database (Denmark)

    Hansen, Johan P.

    spaces of Veronese varieties. Linear network coding transmits information in terms of a basis of a vector space and the information is received as a basis of a possibly altered vector space. Ralf Koetter and Frank R. Kschischang introduced a metric on the set af vector spaces and showed that a minimal......We present a general theory to obtain linear network codes utilizing forms and obtain explicit families of equidimensional vector spaces, in which any pair of distinct vector spaces intersect in the same small dimension. The theory is inspired by the methods of the author utilizing the osculating...... them suitable for linear network coding. The parameters of the resulting linear network codes are determined....

  13. 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.

  14. Growth and form of spherulites

    Science.gov (United States)

    Gránásy, László; Pusztai, Tamás; Tegze, György; Warren, James A.; Douglas, Jack F.

    2005-07-01

    Many structural materials (metal alloys, polymers, minerals, etc.) are formed by quenching liquids into crystalline solids. This highly nonequilibrium process often leads to polycrystalline growth patterns that are broadly termed “spherulites” because of their large-scale average spherical shape. Despite the prevalence and practical importance of spherulite formation, only rather qualitative concepts of this phenomenon exist. It is established that phase field methods naturally account for diffusional instabilities that are responsible for dendritic single-crystal growth. However, a generalization of this model is required to describe spherulitic growth patterns, and in the present paper we propose a minimal model of this fundamental crystal growth process. Our calculations indicate that the diversity of spherulitic growth morphologies arises from a competition between the ordering effect of discrete local crystallographic symmetries and the randomization of the local crystallographic orientation that accompanies crystal grain nucleation at the growth front [growth front nucleation (GFN)]. This randomization in the orientation accounts for the isotropy of spherulitic growth at large length scales and long times. In practice, many mechanisms can give rise to GFN, and the present work describes and explores three physically prevalent sources of disorder that lead to this kind of growth. While previous phase field modeling elucidated two of these mechanisms—disorder created by particulate impurities or other static disorder or by the dynamic heterogeneities that spontaneously form in supercooled liquids (even pure ones)—the present paper considers an additional mechanism, crystalline branching induced by a misorientation-dependent grain boundary energy, which can significantly affect spherulite morphology. We find the entire range of observed spherulite morphologies can be reproduced by this generalized phase field model of polycrystalline growth.

  15. 76 FR 41279 - Agency Information Collection Activities; Form I-864, Form I-864A, Form I-864EZ, and Form I-864W...

    Science.gov (United States)

    2011-07-13

    ... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities; Form I-864, Form I- 864A, Form I-864EZ, and Form I-864W; Extension of an Existing Information Collection; Comment Request ACTION: 30-Day Notice of Information Collection Under Review: Form I- 864, Affidavit of...

  16. 75 FR 51093 - Agency Information Collection Activities: Form I-864, Form I-864A, Form I-864EZ, and Form I-864W...

    Science.gov (United States)

    2010-08-18

    ... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Form I-864, Form I- 864A, Form I-864EZ, and Form I-864W; Extension of a Currently Approved Information Collection; Comment Request ACTION: 30-Day Notice of Information Collection Under Review: Form I- 864, Affidavit...

  17. Disjoint forms in graphical user interfaces

    NARCIS (Netherlands)

    Evers, S.; Achten, P.M.; Plasmeijer, M.J.; Loidl, H.W.

    2006-01-01

    Forms are parts of a graphical user interface (GUI) that show a set of values and allow the user to update them. The declarative form construction library FunctionalForms is extended with disjoint form combinators to capture some common patterns in which the form structure expresses a choice. We dem

  18. The 3D-tomography of the nano-clusters formed by Fe-coating and annealing of diamond films for enhancing their surface electron field emitters

    Directory of Open Access Journals (Sweden)

    Huang-Chin Chen

    2012-09-01

    Full Text Available The Fe-coating and H2-annealed processes markedly increased the conductivity and enhanced the surface electron field emission (s-EFE properties for the diamond films. The enhancement on the s-EFE properties for the diamond films is presumably owing to the formation of nano-graphite clusters on the surface of the films via the Fe-to-diamond interaction. However, the extent of enhancement varied with the granular structure of the diamond films. For the microcrystalline (MCD films, the s-EFE process can be turned on at (E0MCD = 1.9 V/μm, achieving a large s-EFE current density of (JeMCD = 315 μA/cm2 at an applied field of 8.8 V/μm. These s-EFE properties are markedly better than those for Fe-coated/annealed ultrananocrystalline diamond (UNCD films with (E0UNCD = 2.0 V/μm and (JeUNCD = 120 μA/cm2. The transmission electron microscopy showed that the nano-graphite clusters formed an interconnected network for MCD films that facilitated the electron transport more markedly, as compared with the isolated nano-graphitic clusters formed at the surface of the UNCD films. Therefore, the Fe-coating/annealing processes improved the s-EFE properties for the MCD films more markedly than that for the UNCD films. The understanding on the distribution of the nano-clusters is of critical importance in elucidating the authentic factor that influences the s-EFE properties of the diamond films. Such an understanding is possible only through the 3D-tomographic investigations.

  19. 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....

  20. 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 ...