Sample records for cubic zinc blende
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International Nuclear Information System (INIS)
Dong, Ming; Zhang, Jinfeng; Yu, Jiaguo
2015-01-01
Semiconductor zinc sulphide (ZnS) has two common phases: hexagonal wurtzite and cubic zinc-blende structures. The crystal structures, energy band structures, density of states (DOS), bond populations, and optical properties of wurtzite and zinc-blende ZnS were investigated by the density functional theory of first-principles. The similar band gaps and DOS of wurtzite and zinc-blende ZnS were found and implied the similarities in crystal structures. However, the distortion of ZnS 4 tetrahedron in wurtzite ZnS resulted in the production of spontaneous polarization and internal electric field, which was beneficial for the transfer and separation of photogenerated electrons and holes
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Growth of cubic InN on r-plane sapphire
International Nuclear Information System (INIS)
Cimalla, V.; Pezoldt, J.; Ecke, G.; Kosiba, R.; Ambacher, O.; Spiess, L.; Teichert, G.; Lu, H.; Schaff, W.J.
2003-01-01
InN has been grown directly on r-plane sapphire substrates by plasma-enhanced molecular-beam epitaxy. X-ray diffraction investigations have shown that the InN layers consist of a predominant zinc blende (cubic) structure along with a fraction of the wurtzite (hexagonal) phase which content increases with proceeding growth. The lattice constant for zinc blende InN was found to be a=4.986 A. For this unusual growth of a metastable cubic phase on a noncubic substrate an epitaxial relationship was proposed where the metastable zinc blende phase grows directly on the r-plane sapphire while the wurtzite phase arises as the special case of twinning in the cubic structure
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Wurtzite/zinc-blende electronic-band alignment in basal-plane stacking faults in semi-polar GaN
Monavarian, Morteza; Hafiz, Shopan; Izyumskaya, Natalia; Das, Saikat; Özgür, Ümit; Morkoç, Hadis; Avrutin, Vitaliy
2016-02-01
Heteroepitaxial semipolar and nonpolar GaN layers often suffer from high densities of extended defects including basal plane stacking faults (BSFs). BSFs which are considered as inclusions of cubic zinc-blende phase in wurtzite matrix act as quantum wells strongly affecting device performance. Band alignment in BSFs has been discussed as type of band alignment at the wurtzite/zinc blende interface governs the response in differential transmission; fast decay after the pulse followed by slow recovery due to spatial splitting of electrons and heavy holes for type- II band alignment in contrast to decay with no recovery in case of type I band alignment. Based on the results, band alignment is demonstrated to be of type II in zinc-blende segments in wurtzite matrix as in BSFs.
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Half-metallic zinc-blende pnictides in real environments
International Nuclear Information System (INIS)
Shi Lijie; Liu Banggui
2005-01-01
The structural stability of half-metallic zinc-blende pnictides and the robustness of their half-metallic ferromagnetism in the presence of tetragonal and orthorhombic crystalline deformations are studied using a full-potential linear augmented plane wave method within the density-functional theory. The total energies of zinc-blende MnAs, CrAs, and CrSb are proved to increase with deformation increase, in contrast to those of other zinc-blende half-metallic pnictides, and therefore these three are stable against the deformations but the others are not. This is consistent with the experimental fact that only these three have been fabricated. On the other hand, the half-metallic ferromagnetism of the latter two is proved to be robust enough to survive large crystal deformations. This implies that half-metallic ferromagnetism may be achieved experimentally even in substantially deformed zinc-blende ultrathin films or layers of CrAs and CrSb in real environments
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Epitaxially grown zinc-blende structured Mn doped ZnO nanoshell on ZnS nanoparticles
International Nuclear Information System (INIS)
Limaye, Mukta V.; Singh, Shashi B.; Date, Sadgopal K.; Gholap, R.S.; Kulkarni, Sulabha K.
2009-01-01
Zinc oxide in the bulk as well as in the nanocrystalline form is thermodynamically stable in the wurtzite structure. However, zinc oxide in the zinc-blende structure is more useful than that in the wurtzite structure due to its superior electronic properties as well as possibility of efficient doping. Therefore, zinc oxide shell is grown epitaxially on zinc sulphide core nanoparticles having zinc-blende structure. It is shown that doping of manganese could be achieved in zinc oxide nanoshell with zinc-blende structure
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Kozlenko, D P; Ehm, L; Hull, S; Savenko, B N; Shchennikov, V V; Voronin, V I
2003-01-01
The structure of the pseudo-binary mercury chalcogenide alloy HgSe sub 0 sub . sub 7 S sub 0 sub . sub 3 has been studied by x-ray and neutron powder diffraction at pressures up to 8.5 GPa. A phase transition from the cubic zinc blende structure to the hexagonal cinnabar structure was observed at P approx 1 GPa. A phenomenological model of this reconstructive phase transition based on a displacement mechanism is proposed. Analysis of the geometrical relationship between the zinc blende and the cinnabar phases has shown that the possible order parameter for the zinc blende-cinnabar structural transformation is the spontaneous strain e sub 4. This assignment agrees with the previously observed high pressure behaviour of the elastic constants of some mercury chalcogenides.
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International Nuclear Information System (INIS)
Chen, Zhi-Yuan; Xu, Bin; Gao, G.Y.
2013-01-01
The structural, electronic and magnetic properties of zinc-blende TiBi are investigated by using the first-principles full-potential linearized augmented plane-wave method. It is found that zinc-blende TiBi exhibits half-metallic ferromagnetism with the energy gap of 1.39 eV in the minority-spin channel. The calculated total magnetic moment of 1.00 µ B per formula unit mainly originates from the Ti atom. We also show that the half-metallicity of zinc-blende TiBi can be maintained up to 3% compression and 5% expansion of lattice constant with respect to the equilibrium lattice, and zinc-blende TiBi is still half-metallic when the spin–orbit coupling is considered. The robust half-metallicity and low magnetic moment make zinc-blende TiBi a potential candidate for spintronic applications. - Highlights: • Half-metallic ferromagnetism in zinc-blende TiBi. • Zinc-blende TiBi has low magnetic moment of 1.00 µ B /f.u. • Spin–orbit coupling does not destroy the half-metallicity of zinc-blende TiBi
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Half-metallic ferromagnetism in Cu-doped zinc-blende ZnO from first principles study
International Nuclear Information System (INIS)
Li, X.F.; Zhang, J.; Xu, B.; Yao, K.L.
2012-01-01
Electronic structures and magnetism of Cu-doped zinc-blende ZnO have been investigated by the first-principle method based on density functional theory (DFT). The results show that Cu can induce stable ferromagnetic ground state. The magnetic moment of supercell including single Cu atom is 1.0 μ B . Electronic structure shows that Cu-doped zinc-blende ZnO is a p-type half-metallic ferromagnet. The half-metal property is mainly attribute to the crystal field splitting of Cu 3d orbital, and the ferromagnetism is dominated by the hole-mediated double exchange mechanism. Therefore, Cu-doped zinc-blende ZnO should be useful in semiconductor spintronics and other applications. - Highlights: → Magnetism of Cu-doped zinc-blende ZnO. → Cu-doped zinc-blende ZnO shows interesting half-metal character. → Total energies calculations reveal that Cu can induce ferromagnetic ground state. → Ferromagnetism dominated by the hole-mediated double exchange mechanism.
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Young's Modulus of Wurtzite and Zinc Blende InP Nanowires.
Dunaevskiy, Mikhail; Geydt, Pavel; Lähderanta, Erkki; Alekseev, Prokhor; Haggrén, Tuomas; Kakko, Joona-Pekko; Jiang, Hua; Lipsanen, Harri
2017-06-14
The Young's modulus of thin conical InP nanowires with either wurtzite or mixed "zinc blende/wurtzite" structures was measured. It has been shown that the value of Young's modulus obtained for wurtzite InP nanowires (E [0001] = 130 ± 30 GPa) was similar to the theoretically predicted value for the wurtzite InP material (E [0001] = 120 ± 10 GPa). The Young's modulus of mixed "zinc blende/wurtzite" InP nanowires (E [111] = 65 ± 10 GPa) appeared to be 40% less than the theoretically predicted value for the zinc blende InP material (E [111] = 110 GPa). An advanced method for measuring the Young's modulus of thin and flexible nanostructures is proposed. It consists of measuring the flexibility (the inverse of stiffness) profiles 1/k(x) by the scanning probe microscopy with precise control of loading force in nanonewton range followed by simulations.
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Surface half-metallicity and stability of zinc-blende sodium monoselenide
International Nuclear Information System (INIS)
Tabatabaeifar, A.; Davatolhagh, S.; Moradi, M.
2017-01-01
Highlights: • Density functional study reveals. • Robust half-metallicity of zinc-blende NaSe (001) surfaces. • Stable against phase separation as indicated by negative formation energy. • Magnetically stable at room temperature because of high Curie temperature. • Surfaces are stable as indicated by low surface energies. • Therefore, zinc-blende NaSe promising candidate as spin injection material. - Abstract: The electronic structure and magnetic properties of relaxed (001) surfaces of the sp-electron half-metallic ferromagnet NaSe in the zinc-blende phase, are calculated on the basis of first principle density functional theory within the framework of self-consistent field plane wave pseudo-potential method, using the generalized gradient approximation for the exchange-correlation functional. The results of this study reveal that both Na- and Se-terminated surfaces retain the robust bulk half-metallic property. The negative value found for the bulk formation energy indicates that this material is stable against phase separation. We also obtain the surface energies and discuss their stability via the calculated bulk formation energy. The Curie temperature is estimated to be 920 K within mean field approximation, which is well above the room temperature. In the light of the above, zinc-blende NaSe appears to be a good candidate for spintronic applications as spin injection material.
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Mechanical, Thermodynamic and Electronic Properties of Wurtzite and Zinc-Blende GaN Crystals
Luan, Xinghe; Feng, Chuang; Yang, Daoguo; Zhang, Guoqi
2017-01-01
For the limitation of experimental methods in crystal characterization, in this study, the mechanical, thermodynamic and electronic properties of wurtzite and zinc-blende GaN crystals were investigated by first-principles calculations based on density functional theory. Firstly, bulk moduli, shear moduli, elastic moduli and Poisson’s ratios of the two GaN polycrystals were calculated using Voigt and Hill approximations, and the results show wurtzite GaN has larger shear and elastic moduli and exhibits more obvious brittleness. Moreover, both wurtzite and zinc-blende GaN monocrystals present obvious mechanical anisotropic behavior. For wurtzite GaN monocrystal, the maximum and minimum elastic moduli are located at orientations [001] and , respectively, while they are in the orientations and for zinc-blende GaN monocrystal, respectively. Compared to the elastic modulus, the shear moduli of the two GaN monocrystals have completely opposite direction dependences. However, different from elastic and shear moduli, the bulk moduli of the two monocrystals are nearly isotropic, especially for the zinc-blende GaN. Besides, in the wurtzite GaN, Poisson’s ratios at the planes containing [001] axis are anisotropic, and the maximum value is 0.31 which is located at the directions vertical to [001] axis. For zinc-blende GaN, Poisson’s ratios at planes (100) and (111) are isotropic, while the Poisson’s ratio at plane (110) exhibits dramatically anisotropic phenomenon. Additionally, the calculated Debye temperatures of wurtzite and zinc-blende GaN are 641.8 and 620.2 K, respectively. At 300 K, the calculated heat capacities of wurtzite and zinc-blende are 33.6 and 33.5 J mol−1 K−1, respectively. Finally, the band gap is located at the G point for the two crystals, and the band gaps of wurtzite and zinc-blende GaN are 3.62 eV and 3.06 eV, respectively. At the G point, the lowest energy of conduction band in the wurtzite GaN is larger, resulting in a wider band gap
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Mechanical, Thermodynamic and Electronic Properties of Wurtzite and Zinc-Blende GaN Crystals
Directory of Open Access Journals (Sweden)
Hongbo Qin
2017-12-01
Full Text Available For the limitation of experimental methods in crystal characterization, in this study, the mechanical, thermodynamic and electronic properties of wurtzite and zinc-blende GaN crystals were investigated by first-principles calculations based on density functional theory. Firstly, bulk moduli, shear moduli, elastic moduli and Poisson’s ratios of the two GaN polycrystals were calculated using Voigt and Hill approximations, and the results show wurtzite GaN has larger shear and elastic moduli and exhibits more obvious brittleness. Moreover, both wurtzite and zinc-blende GaN monocrystals present obvious mechanical anisotropic behavior. For wurtzite GaN monocrystal, the maximum and minimum elastic moduli are located at orientations [001] and <111>, respectively, while they are in the orientations <111> and <100> for zinc-blende GaN monocrystal, respectively. Compared to the elastic modulus, the shear moduli of the two GaN monocrystals have completely opposite direction dependences. However, different from elastic and shear moduli, the bulk moduli of the two monocrystals are nearly isotropic, especially for the zinc-blende GaN. Besides, in the wurtzite GaN, Poisson’s ratios at the planes containing [001] axis are anisotropic, and the maximum value is 0.31 which is located at the directions vertical to [001] axis. For zinc-blende GaN, Poisson’s ratios at planes (100 and (111 are isotropic, while the Poisson’s ratio at plane (110 exhibits dramatically anisotropic phenomenon. Additionally, the calculated Debye temperatures of wurtzite and zinc-blende GaN are 641.8 and 620.2 K, respectively. At 300 K, the calculated heat capacities of wurtzite and zinc-blende are 33.6 and 33.5 J mol−1 K−1, respectively. Finally, the band gap is located at the G point for the two crystals, and the band gaps of wurtzite and zinc-blende GaN are 3.62 eV and 3.06 eV, respectively. At the G point, the lowest energy of conduction band in the wurtzite GaN is larger
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Mechanical, Thermodynamic and Electronic Properties of Wurtzite and Zinc-Blende GaN Crystals.
Qin, Hongbo; Luan, Xinghe; Feng, Chuang; Yang, Daoguo; Zhang, Guoqi
2017-12-12
For the limitation of experimental methods in crystal characterization, in this study, the mechanical, thermodynamic and electronic properties of wurtzite and zinc-blende GaN crystals were investigated by first-principles calculations based on density functional theory. Firstly, bulk moduli, shear moduli, elastic moduli and Poisson's ratios of the two GaN polycrystals were calculated using Voigt and Hill approximations, and the results show wurtzite GaN has larger shear and elastic moduli and exhibits more obvious brittleness. Moreover, both wurtzite and zinc-blende GaN monocrystals present obvious mechanical anisotropic behavior. For wurtzite GaN monocrystal, the maximum and minimum elastic moduli are located at orientations [001] and , respectively, while they are in the orientations and for zinc-blende GaN monocrystal, respectively. Compared to the elastic modulus, the shear moduli of the two GaN monocrystals have completely opposite direction dependences. However, different from elastic and shear moduli, the bulk moduli of the two monocrystals are nearly isotropic, especially for the zinc-blende GaN. Besides, in the wurtzite GaN, Poisson's ratios at the planes containing [001] axis are anisotropic, and the maximum value is 0.31 which is located at the directions vertical to [001] axis. For zinc-blende GaN, Poisson's ratios at planes (100) and (111) are isotropic, while the Poisson's ratio at plane (110) exhibits dramatically anisotropic phenomenon. Additionally, the calculated Debye temperatures of wurtzite and zinc-blende GaN are 641.8 and 620.2 K, respectively. At 300 K, the calculated heat capacities of wurtzite and zinc-blende are 33.6 and 33.5 J mol -1 K -1 , respectively. Finally, the band gap is located at the G point for the two crystals, and the band gaps of wurtzite and zinc-blende GaN are 3.62 eV and 3.06 eV, respectively. At the G point, the lowest energy of conduction band in the wurtzite GaN is larger, resulting in a wider band gap. Densities of
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Energy Technology Data Exchange (ETDEWEB)
Wang Lan, E-mail: lwang322@yahoo.com.cn [Department of Applied Physics, Harbin Institute of Technology, Harbin 150001 (China); Department of Physics, Harbin Medical University, Harbin 150081 (China); Sun Xiudong, E-mail: xdsun@hit.edu.cn [Department of Applied Physics, Harbin Institute of Technology, Harbin 150001 (China); Liu Wenjing [Department of Astronautic Science and Mechanics, Harbin Institute of Technology, Harbin 150001 (China); Liu Bingyi [Laboratory Center for the School of Pharmacy, Harbin Medical University, Harbin 150081 (China)
2010-03-15
Safe, common, and low-cost compounds were used as solvents for the non-tri-n-octylphosphine (TOP) synthesis of high quality CdSe nanocrystals (NCs) in open air. In oleic acid-paraffin liquid system, CdSe nanocrystals in the less common zinc-blende (ZB, cubic) crystal structure have been obtained. The effects of adding n-hexadecylamine (HDA) to different solutions were discussed. Stable, highly homogeneous and luminescent CdSe nanocrystals were formed by adding n-hexadecylamine to Cd solution rather than to Se solution. Without any size sorting, the size distribution of the nanocrystals can be readily controlled and the highest photoluminescence (PL) quantum efficiency (QE) of the nanocrystals was up to 20-30%.
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International Nuclear Information System (INIS)
Wang Lan; Sun Xiudong; Liu Wenjing; Liu Bingyi
2010-01-01
Safe, common, and low-cost compounds were used as solvents for the non-tri-n-octylphosphine (TOP) synthesis of high quality CdSe nanocrystals (NCs) in open air. In oleic acid-paraffin liquid system, CdSe nanocrystals in the less common zinc-blende (ZB, cubic) crystal structure have been obtained. The effects of adding n-hexadecylamine (HDA) to different solutions were discussed. Stable, highly homogeneous and luminescent CdSe nanocrystals were formed by adding n-hexadecylamine to Cd solution rather than to Se solution. Without any size sorting, the size distribution of the nanocrystals can be readily controlled and the highest photoluminescence (PL) quantum efficiency (QE) of the nanocrystals was up to 20-30%.
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International Nuclear Information System (INIS)
Fan, S.W.; Li, W.B.; Yang, L.; Huang, X.P.; Ding, L.J.; Yao, K.L.
2015-01-01
Abstracts: Utilizing the full potential linearized augment plane wave method with the modified Becke–Johnson potential, the half-metallicity and electronic structures of zinc blend YSi and YSi/CdTe interfaces were investigated. Calculations show the equilibrium lattice parameter for zinc blend YSi is 6.57 Angstrom, which is good compatibility with CdTe. Under theoretical equilibrium lattice parameters, zinc blend YSi is a half-metallic ferromagnet. The total magnetic moment is 1.00 μ B per cell. Electronic structures show the half-metallic gap is 0.391 eV and p-d hybridization mechanism plays a crucial role in forming half-metallic ferromagnetism. Half-metallic ferromagnetism preserved in YSi/CdTe interfaces implies CdTe would be a promising substrate for epitaxial growth zinc blend YSi films. Negative cohesive energy and heat of formation indicate zinc blend YSi could be fabricated experimentally. - Highlights: • Zinc blend YSi is good compatibility with CdTe. • Zinc blend YSi is a half-metallic ferromagnet with 0.391 eV half-metallic gap. • Negative cohesive energy and heat of formation indicate YSi could be synthesized. • Half-metallicity for YSi/CdTe slabs shows CdTe could be used to fabricate YSi film
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Energy Technology Data Exchange (ETDEWEB)
Fan, S.W., E-mail: fansw1129@126.com [Department of Physics, China Three Gorges University, Yichang 443002 (China); Li, W.B. [School of Physics and Chemistry, Henan Polytechnic University, Jiaozuo 454000 (China); Yang, L.; Huang, X.P.; Ding, L.J. [Department of Physics, China Three Gorges University, Yichang 443002 (China); Yao, K.L. [School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074 (China)
2015-08-01
Abstracts: Utilizing the full potential linearized augment plane wave method with the modified Becke–Johnson potential, the half-metallicity and electronic structures of zinc blend YSi and YSi/CdTe interfaces were investigated. Calculations show the equilibrium lattice parameter for zinc blend YSi is 6.57 Angstrom, which is good compatibility with CdTe. Under theoretical equilibrium lattice parameters, zinc blend YSi is a half-metallic ferromagnet. The total magnetic moment is 1.00 μ{sub B} per cell. Electronic structures show the half-metallic gap is 0.391 eV and p-d hybridization mechanism plays a crucial role in forming half-metallic ferromagnetism. Half-metallic ferromagnetism preserved in YSi/CdTe interfaces implies CdTe would be a promising substrate for epitaxial growth zinc blend YSi films. Negative cohesive energy and heat of formation indicate zinc blend YSi could be fabricated experimentally. - Highlights: • Zinc blend YSi is good compatibility with CdTe. • Zinc blend YSi is a half-metallic ferromagnet with 0.391 eV half-metallic gap. • Negative cohesive energy and heat of formation indicate YSi could be synthesized. • Half-metallicity for YSi/CdTe slabs shows CdTe could be used to fabricate YSi film.
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Shin, Hyeonwoo; Kang, Chan-mo; Baek, Kyu-Ha; Kim, Jun Young; Do, Lee-Mi; Lee, Changhee
2018-05-01
We present a novel methods of fabricating low-temperature (180 °C), solution-processed zinc oxide (ZnO) transistors using a ZnO precursor that is blended with zinc hydroxide [Zn(OH)2] and zinc oxide hydrate (ZnO • H2O) in an ammonium solution. By using the proposed method, we successfully improved the electrical performance of the transistor in terms of the mobility (μ), on/off current ratio (I on/I off), sub-threshold swing (SS), and operational stability. Our new approach to forming a ZnO film was systematically compared with previously proposed methods. An atomic forced microscopic (AFM) image and an X-ray photoelectron spectroscopy (XPS) analysis showed that our method increases the ZnO crystallite size with less OH‑ impurities. Thus, we attribute the improved electrical performance to the better ZnO film formation using the blending methods.
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Mitzi, David B
2005-10-03
Two hydrazine zinc(II) telluride polymorphs, (N2H4)2ZnTe, have been isolated, using ambient-temperature solution-based techniques, and the crystal structures determined: alpha-(N2H4)2ZnTe (1) [P21, a = 7.2157(4) Angstroms, b = 11.5439(6) Angstroms, c = 7.3909(4) Angstroms, beta = 101.296(1) degrees, Z = 4] and beta-(N2H4)2ZnTe (2) [Pn, a = 8.1301(5) Angstroms, b = 6.9580(5) Angstroms, c = 10.7380(7) Angstroms, beta = 91.703(1) degrees, Z = 4]. The zinc atoms in 1 and 2 are tetrahedrally bonded to two terminal hydrazine molecules and two bridging tellurium atoms, leading to the formation of extended one-dimensional (1-D) zinc telluride chains, with different chain conformations and packings distinguishing the two polymorphs. Thermal decomposition of (N2H4)2ZnTe first yields crystalline wurtzite (hexagonal) ZnTe at temperatures as low as 200 degrees C, followed by the more stable zinc blende (cubic) form at temperatures above 350 degrees C. The 1-D polymorphs are soluble in hydrazine and can be used as convenient precursors for the low-temperature solution processing of p-type ZnTe semiconducting films.
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Park, Yeonjoon (Inventor); Kim, Hyun Jung (Inventor); Skuza, Jonathan R. (Inventor); Lee, Kunik (Inventor); King, Glen C. (Inventor); Choi, Sang Hyouk (Inventor)
2017-01-01
An X-ray defraction (XRD) characterization method for sigma=3 twin defects in cubic semiconductor (100) wafers includes a concentration measurement method and a wafer mapping method for any cubic tetrahedral semiconductor wafers including GaAs (100) wafers and Si (100) wafers. The methods use the cubic semiconductor's (004) pole figure in order to detect sigma=3/{111} twin defects. The XRD methods are applicable to any (100) wafers of tetrahedral cubic semiconductors in the diamond structure (Si, Ge, C) and cubic zinc-blend structure (InP, InGaAs, CdTe, ZnSe, and so on) with various growth methods such as Liquid Encapsulated Czochralski (LEC) growth, Molecular Beam Epitaxy (MBE), Organometallic Vapor Phase Epitaxy (OMVPE), Czochralski growth and Metal Organic Chemical Vapor Deposition (MOCVD) growth.
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Directory of Open Access Journals (Sweden)
BG Sarvari
2015-12-01
Full Text Available ABSTRACT This experiment was carried out to evaluate the effect of different dietary supplementation levels of zinc oxide and of an organic acid blend on broiler performance, carcass traits, and serum parameters. A total of 2400 one-day-old male Ross 308 broiler chicks, with average initial body weight 44.21±0.19g, was distributed according to a completely randomized design in a 2 x 3 factorial arrangement. Six treatments, consisting of diets containing two zinc oxide levels (0 and 0.01% of the diet and three organic acid blend levels (0, 0.15, and 0.30% were applied, with eight replicates of 50 birds each. The experimental diets were supplied ad libitum for 42 days. There were significant performance differences among birds fed the different zinc oxide and organic acid blend levels until 42 d of age (p<0.01. The result of this experiment showed that the organic acid blend did not affect feed intake, but zinc oxide increased feed intake. Carcass traits were not influenced by the experimental supplements. Zinc oxide supplementation increased serum alkaline phosphatase level (p<0.01. The organic acid blend reduced serum cholesterol and triglyceride levels (p<0.05. No interactions were found between zinc oxide and the organic acid blend for none of the evaluated parameters. We concluded that zinc oxide and the evaluated organic acid blend improve broiler performance.
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Structural properties of III-V zinc-blende semiconductors under pressure
International Nuclear Information System (INIS)
Froyen, S.; Cohen, M.L.
1983-01-01
The pseudopotential method within the local-density approximation is used to investigate the static and structural properties of some III-V compound semiconductors. Comparisons of calculated total energies as a function of volume and structure yield information about solid-solid phase transformations. At high pressures the results indicate that several metallic structures are lower in energy than the zinc-blende structure. From our results the compounds (AlP, AlAs, GaP, and GaAs) can be divided into two classes. In the Ga compounds, we find a pressure-induced phase transformation to either rocksalt, β-Sn, or NiAs, whereas in the Al compounds rocksalt and NiAs are stabilized with respect to β-Sn. All structures except zinc blende are metallic. We discuss the electronic structure of each phase and show how it relates to structural stability
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New transformation mechanism for a zinc-blende to rocksalt phase transformation in MgS
International Nuclear Information System (INIS)
Durandurdu, Murat
2009-01-01
The stability of the zinc-blende structured MgS is studied using a constant pressure ab initio molecular dynamics technique. A phase transition into a rocksalt structure is observed through the simulation. The zinc-blende to rocksalt phase transformation proceeds via two rhombohedral intermediate phases within R3m (No:160) and R3-barm (No:166) symmetries and does not involve any bond breaking. This mechanism is different from the previously observed mechanism in molecular dynamics simulations. (fast track communication)
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Size and temperature dependence of the tensile mechanical properties of zinc blende CdSe nanowires
International Nuclear Information System (INIS)
Fu, Bing; Chen, Na; Xie, Yiqun; Ye, Xiang; Gu, Xiao
2013-01-01
The effect of size and temperature on the tensile mechanical properties of zinc blende CdSe nanowires is investigated by all atoms molecular dynamic simulation. We found the ultimate tensile strength and Young's modulus will decrease as the temperature and size of the nanowire increase. The size and temperature dependence are mainly attributed to surface effect and thermally elongation effect. High reversibility of tensile behavior will make zinc blende CdSe nanowires suitable for building efficient nanodevices.
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Ofuchi, H; Ono, K; Oshima, M; Akinaga, H; Manago, T
2003-01-01
In this work, geometric structures for a half-metallic ferromagnet 'zinc-blende CrAs', which showed ferromagnetic behavior beyond room temperature, were investigated using fluorescence extended X-ray absorption fine structure (EXAFS) measurement. The EXAFS measurements revealed that As atoms around Cr atoms in the 2 nm CrAs film grown on a GaAs(0 0 1) substrate were coordinated tetrahedrally, indicating formation of zinc-blende CrAs. The Cr-As bond length in the zinc-blende CrAs is 2.49 A. This value is close to that which was estimated from the lattice constant (5.82 A) of ferromagnetic zinc-blende CrAs calculated by full-potential linearized augmented-plane wave method. The EXAFS analysis show that the theoretically predicted zinc-blende CrAs can be fabricated on GaAs(0 0 1) substrate by low-temperature molecular-beam epitaxy.
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International Nuclear Information System (INIS)
Ofuchi, H.; Mizuguchi, M.; Ono, K.; Oshima, M.; Akinaga, H.; Manago, T.
2003-01-01
In this work, geometric structures for a half-metallic ferromagnet 'zinc-blende CrAs', which showed ferromagnetic behavior beyond room temperature, were investigated using fluorescence extended X-ray absorption fine structure (EXAFS) measurement. The EXAFS measurements revealed that As atoms around Cr atoms in the 2 nm CrAs film grown on a GaAs(0 0 1) substrate were coordinated tetrahedrally, indicating formation of zinc-blende CrAs. The Cr-As bond length in the zinc-blende CrAs is 2.49 A. This value is close to that which was estimated from the lattice constant (5.82 A) of ferromagnetic zinc-blende CrAs calculated by full-potential linearized augmented-plane wave method. The EXAFS analysis show that the theoretically predicted zinc-blende CrAs can be fabricated on GaAs(0 0 1) substrate by low-temperature molecular-beam epitaxy
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International Nuclear Information System (INIS)
Xiao, H.Y.; Gao, Fei; Zu, X.T.; Weber, W.J.
2010-01-01
High-pressure induced zinc blende to rocksalt phase transition in GaN has been investigated by ab initio molecular dynamics method to characterize the transformation mechanism at the atomic level. It was shown that at 100 GPa GaN passes through tetragonal and monoclinic states before rocksalt structure is formed. The transformation mechanism is consistent with that for other zinc blende semiconductors obtained from the same method. Detailed structural analysis showed that there is no bond breaking involved in the phase transition.
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International Nuclear Information System (INIS)
Lepkowski, S.P.; Majewski, J.A.
2004-01-01
We studied the nonlinear elasticity effects for the case of III-N compounds. Particularly, we determined the pressure dependences of elastic constants, in zinc-blende InN, GaN, and AlN by performing ab initio calculations in the framework of plane-wave pseudopotential implementation of the density-functional theory. We found significant and almost linear increase in C 11 , C 12 with pressure for considered nitrides compounds. Much weaker dependences on pressure was observed for C 44 . We also discussed pressure dependences of two-dimensional Poisson's ratio and elastic anisotropy coefficient. Finally, we showed that the pressure dependence of elastic constants results in significant reduction of the pressure coefficient of the energy emission in cubic InGaN/GaN quantum well and essentially improves the agreement between experimental and theoretical values. (author)
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Half-metallicity and ferromagnetism of TcX (X=C, Si and Ge) in zinc blende structure
Energy Technology Data Exchange (ETDEWEB)
Liu, Yong [College of Science, Yanshan University, Qinhuangdao 066004 (China); Physics Department, Brock University, St. Catharines, ON, Canada L2S 3A1 (Canada); Xing, Yue [College of Science, Yanshan University, Qinhuangdao 066004 (China); Bose, S.K., E-mail: sbose@brocku.ca [Physics Department, Brock University, St. Catharines, ON, Canada L2S 3A1 (Canada); Zhao, Yong-Hong [Department of Physics, Sichuan Normal University, Chengdu 610068 (China)
2013-02-15
We report results of a first-principles density-functional study of three binary transition-metal compounds TcX (X=C, Si and Ge) in the hypothetical cubic zinc blende (ZB) structure. Our calculations are based on the full potential linear augmented plane wave (FP-LAPW) plus local orbitals method, together with generalized gradient approximation for the exchange-correlation potential. Half-metallic (HM) ferromagnetism is observed in these binary compounds for their optimized cell volumes. In the HM state, these compounds possess an integer magnetic moment (1.000{mu}{sub B}) per formula unit, which is one of the important characteristics of half-metallic ferromagnets (HMFs). The ferromagnetic (FM) state is found to be stable for ZB TcC, TcSi and TcGe against the nonmagnetic (NM) and antiferromagnetic (AFM) states. Calculations show that half-metallicity can be maintained for a wide range of lattice constants in these binary compounds. Density functional calculations of exchange interactions and the Curie temperatures reveal similar trends for the three compounds with respect to the lattice parameter. These compounds are compatible with the traditional semiconductors, and could be useful in spin-electronics and other applications. The most important aspect of this work is to explore the possibility of not only magnetism, but HM ferromagnetism in compounds involving NM elements and 4d transition element Tc. - Highlights: Black-Right-Pointing-Pointer We study magnetism of the compounds TcSi, TcC, and TcGe. Black-Right-Pointing-Pointer These compounds, with nonmagnetic constituents, are found to be ferromagnetic. Black-Right-Pointing-Pointer They show robust half-metallicity in zinc blende structure. Black-Right-Pointing-Pointer Estimated Curie temperatures suggest that synthesis of these compounds is worth pursuing.
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Growth of InAs Wurtzite Nanocrosses from Hexagonal and Cubic Basis
DEFF Research Database (Denmark)
Krizek, Filip; Kanne, Thomas; Razmadze, Davydas
2017-01-01
. Two methods use conventional wurtzite nanowire arrays as a 6-fold hexagonal basis for growing single crystal wurtzite nanocrosses. A third method uses the 2-fold cubic symmetry of (100) substrates to form well-defined coherent inclusions of zinc blende in the center of the nanocrosses. We show......Epitaxially connected nanowires allow for the design of electron transport experiments and applications beyond the standard two terminal device geometries. In this Letter, we present growth methods of three distinct types of wurtzite structured InAs nanocrosses via the vapor-liquid-solid mechanism...
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Microstructural characterisation of zinc-blende Ga1-xMnxN grown by MBE as a function of Mn flux
International Nuclear Information System (INIS)
Han, Y; Fay, M W; Novikov, S V; Edmonds, K W; Gallagher, B L; Campion, R P; Staddon, C R; Foxon, C T; Brown, P D
2006-01-01
Zinc-blende Ga 1-x Mn x N epilayers grown by plasma assisted molecular beam epitaxy as a function of Mn flux have been assessed using a variety of structural characterisation techniques. Increasing Mn flux is associated with the build up of a Mn surfactant layer during the early states of growth and a transition from zinc-blende single phase growth to zincblende/ wurtzite mixed phase growth
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International Nuclear Information System (INIS)
Gonzalez, D; Lozano, J G; Herrera, M; Morales, F M; GarcIa, R; Ruffenach, S; Briot, O
2010-01-01
Uncapped InN nanostructures undergo a deleterious natural aging process at ambient conditions by oxygen incorporation. The phases involved in this process and their localization is mapped by transmission electron microscopy (TEM)-related techniques. The parent wurtzite InN (InN-w) phase disappears from the surface and gradually forms a highly textured cubic layer that completely wraps up a InN-w nucleus which still remains from the original single-crystalline quantum dots. The good reticular relationships between the different crystals generate low misfit strains and explain the apparent easiness for phase transformations at room temperature and pressure conditions, but also disable the classical methods to identify phases and grains from TEM images. The application of the geometrical phase algorithm in order to form numerical moire mappings and RGB multilayered image reconstructions allows us to discern among the different phases and grains formed inside these nanostructures. Samples aged for shorter times reveal the presence of metastable InN:O zinc blende (zb) volumes, which act as the intermediate phase between the initial InN-w and the most stable cubic In 2 O 3 end phase. These cubic phases are highly twinned with a proportion of 50:50 between both orientations. We suggest that the existence of the intermediate InN:O-zb phase should be seriously considered to understand the reason for the widely scattered reported fundamental properties of thought to be InN-w, as its bandgap or superconductivity.
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Predicted bond length variation in wurtzite and zinc-blende InGaN and AlGaN alloys
International Nuclear Information System (INIS)
Mattila, T.; Zunger, A.
1999-01-01
Valence force field simulations utilizing large supercells are used to investigate the bond lengths in wurtzite and zinc-blende In x Ga 1-x N and Al x Ga 1-x N random alloys. We find that (i) while the first-neighbor cation endash anion shell is split into two distinct values in both wurtzite and zinc-blende alloys (R Ga-N 1 ≠R In-N 1 ), the second-neighbor cation endash anion bonds are equal (R Ga-N 2 =R In-N 2 ). (ii) The second-neighbor cation endash anion bonds exhibit a crucial difference between wurtzite and zinc-blende binary structures: in wurtzite we find two bond distances which differ in length by 13% while in the zinc-blende structure there is only one bond length. This splitting is preserved in the alloy, and acts as a fingerprint, distinguishing the wurtzite from the zinc-blende structure. (iii) The small splitting of the first-neighbor cation endash anion bonds in the wurtzite structure due to nonideal c/a ratio is preserved in the alloy, but is obscured by the bond length broadening. (iv) The cation endash cation bond lengths exhibit three distinct values in the alloy (Ga endash Ga, Ga endash In, and In endash In), while the anion endash anion bonds are split into two values corresponding to N endash Ga endash N and N endash In endash N. (v) The cation endash related splitting of the bonds and alloy broadening are considerably larger in InGaN alloy than in AlGaN alloy due to larger mismatch between the binary compounds. (vi) The calculated first-neighbor cation endash anion and cation endash cation bond lengths in In x Ga 1-x N alloy are in good agreement with the available experimental data. The remaining bond lengths are provided as predictions. In particular, the predicted splitting for the second-neighbor cation endash anion bonds in the wurtzite structure awaits experimental testing. copyright 1999 American Institute of Physics
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Mechanical, thermodynamic and electronic properties of wurtzite and zinc-blende GaN crystals
Qin, Hongbo; Luan, Xinghe; Feng, Chuang; Yang, Daoguo; Zhang, G.Q.
2017-01-01
For the limitation of experimental methods in crystal characterization, in this study, the mechanical, thermodynamic and electronic properties of wurtzite and zinc-blende GaN crystals were investigated by first-principles calculations based on density functional theory. Firstly, bulk moduli,
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Optical properties of single wurtzite/zinc-blende ZnSe nanowires grown at low temperature
Energy Technology Data Exchange (ETDEWEB)
Zannier, V. [IOM-CNR Laboratorio TASC, S. S. 14, Km. 163.5, I-34149 Trieste (Italy); Department of Physics, University of Trieste, Via Valerio 2, I-34127 Trieste (Italy); Cremel, T.; Kheng, K. [Univ. Grenoble Alpes, F-38000 Grenoble (France); CEA, INAC-SP2M, « Nanophysique et Semiconducteurs » Group, F-38000 Grenoble (France); Artioli, A.; Ferrand, D. [Univ. Grenoble Alpes, F-38000 Grenoble (France); CNRS, Institut Néel, « Nanophysique et Semiconducteurs » Group, F-38000 Grenoble (France); Grillo, V. [IMEM-CNR, Parco Area delle Scienze 37/A, I-43010 Parma (Italy); S3 NANO-CNR, Via Campi 213/A, I-41125 Modena (Italy); Rubini, S. [IOM-CNR Laboratorio TASC, S. S. 14, Km. 163.5, I-34149 Trieste (Italy)
2015-09-07
ZnSe nanowires with a dominant wurtzite structure have been grown at low temperature (300 °C) by molecular beam epitaxy assisted by solid Au nanoparticles. The nanowires emission is polarized perpendicularly to their axis in agreement with the wurtzite selection rules. Alternations of wurtzite and zinc-blende regions have been observed by transmission electron microscopy, and their impact on the nanowires optical properties has been studied by microphotoluminescence. The nanowires show a dominant intense near-band-edge emission as well as the ZnSe wurtzite free exciton line. A type II band alignment between zinc-blende and wurtzite ZnSe is evidenced by time-resolved photoluminescence. From this measurement, we deduce values for the conduction and valence band offsets of 98 and 50 meV, respectively.
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Energy Band Structure Studies Of Zinc-Blende GaAs and InAs ...
African Journals Online (AJOL)
A self-consistent calculation of the structural and electronic properties of zinc blende GaAs and InAs has been carried out. The calculations were done using the full potential-linearized augmented plane wave (FPLAPW) method within the density functional theory (DFT). The exchange-correlation energy used is the ...
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Structural and thermomechanical properties of the zinc-blende AlX (X = P, As, Sb) compounds
Ha, Vu Thi Thanh; Hung, Vu Van; Hanh, Pham Thi Minh; Nguyen, Viet Tuyen; Hieu, Ho Khac
2017-08-01
The structural and thermomechanical properties of zinc-blende aluminum class of III-V compounds have been studied based on the statistical moment method (SMM) in quantum statistical mechanics. Within the SMM scheme, we derived the analytical expressions of the nearest-neighbor distance, thermal expansion coefficient, atomic mean-square displacement and elastic moduli (Young’s modulus, bulk modulus and shear modulus). Numerical calculations have been performed for zinc-blende AlX (X = As, P, Sb) at ambient conditions up to the temperature of 1000 K. Our results are in good and reasonable agreements with earlier measurements and can provide useful references for future experimental and theoretical works. This research presents a systematic approach to investigate the thermodynamic and mechanical properties of materials.
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DEFF Research Database (Denmark)
Duggen, Lars; Willatzen, Morten; Lassen, Benny
2008-01-01
direction show important changes in strain and the electric distribution due to piezoelectric effects. The findings indicate the quantitative importance of a fully coupled model even for zinc blende, in particular when discussing electronic band structure and optoelectronic properties....
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Molecular beam epitaxial growth and characterization of zinc-blende ZnMgSe on InP (001)
International Nuclear Information System (INIS)
Sohel, Mohammad; Munoz, Martin; Tamargo, Maria C.
2004-01-01
High crystalline quality zinc-blende structure Zn (1-x) Mg x Se epitaxial layers were grown on InP (001) substrates by molecular beam epitaxy. Their band gap energies were determined as a function of Mg concentration and a linear dependence was observed. The band gap of the Zn (1-x) Mg x Se closely lattice matched to InP was found to be 3.59 eV at 77 K and the extrapolated value for zinc-blende MgSe was determined to be 3.74 eV. Quantum wells of Zn (1-x) Cd x Se with Zn (1-x) Mg x Se as the barrier layer were grown which exhibit near ultraviolet emission
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First-principles study on half-metallic zinc-blende CrS and its (001) surface
Energy Technology Data Exchange (ETDEWEB)
Xu, Bin, E-mail: hnsqxb@163.com [Department of Mathematics and Information Sciences, North China university of Water Resources and Electric Power, Zhengzhou 450011 (China); Chen, Leiming [Zhengzhou Institute of Aeronautical Industry Management, Zhengzhou, 450015 (China)
2016-11-01
Half-metallic magnets with complete (100%) spin polarization have attracted growing interest due to the potential in spintronic applications. In this paper, we use the first-principles calculations to explain the seeming contradiction between the recent experimental ferromagnetism (Demper et al., 2012 [22]) and the previous theoretical antiferromagnetic ground state for half-metallic zinc-blende CrS, and the experimental ferromagnetism of zinc-blende CrS arises from the substrate effect. We also show that both Cr- and S-terminated (001) surfaces of CrS preserve the bulk half-metallicity. The calculated surface energy indicates that the S-terminated (001) surface is more stable than the Cr-terminated (001) surface within the whole effective Cr chemical potentials, and thus the S-terminated (001) surface is more likely than the Cr-terminated (001) surface when the CrS thin films are grown on ZnSe substrate.
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International Nuclear Information System (INIS)
Siddiqua, Poppy; O'Leary, Stephen K.
2016-01-01
Within the framework of a semi-classical three-valley Monte Carlo electron transport simulation approach, we analyze the steady-state and transient aspects of the electron transport within bulk zinc-blende indium nitride, with a focus on the response to variations in the crystal temperature and the doping concentration. We find that while the electron transport associated with zinc-blende InN is highly sensitive to the crystal temperature, it is not very sensitive to the doping concentration selection. The device consequences of these results are then explored.
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DEFF Research Database (Denmark)
Chantis, Athanasios N.; Christensen, Niels Egede; Svane, Axel
2010-01-01
. In the first, the spin splitting is completely suppressed for one of the bands and doubled for the other. In the second, the absolute value of the splitting is markedly enhanced for both bands approaching the magnitude of the hybridization gap. We demonstrate these effects in zinc-blende semiconductors...
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The stability and half-metallicity of (001) surface and (001) interface based on zinc blende MnAs
Han, Hongpei; Feng, Tuanhui; Zhang, Chunli; Feng, Zhibo; Li, Ming; Yao, K. L.
2018-06-01
Motivated by the growth of MnAs/GaAs thin films in many experimental researches, we investigate the electronic and magnetic properties of bulk, (001) surfaces and (001) interfaces for zinc blende MnAs by means of first-principle calculations. It is confirmed that zinc blende MnAs is a nearly half-metallic ferromagnet with 4.00 μB magnetic moment. The calculated density of states show that the half-metallicity exists in As-terminated (001) surface while it is lost in Mn-terminated (001) surface. For the (001) interfaces of MnAs with semiconductor GaAs, it is found that As-Ga and Mn-As interfaces not only have higher spin polarization but also are more stable among the four considered interfaces. Our results would be helpful to grow stable and high polarized thin films or multilayers for the practical applications of spintronic devices.
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International Nuclear Information System (INIS)
Brik, M.G.; Łach, P.; Karczewski, G.; Wojtowicz, T.; Kamińska, A.; Suchocki, A.
2013-01-01
Luminescence of CdTe quantum dots embedded in ZnTe is quenched at pressure of about 4.5 GPa in the high-pressure experiments. This pressure-induced quenching is attributed to the “zinc-blende–cinnabar” phase transition in CdTe, which was confirmed by the first-principles calculations. Theoretical analysis of the pressure at which the phase transition occurs for CdTe was performed using the CASTEP module of Materials Studio package with both generalized gradient approximation (GGA) and local density approximation (LDA). The calculated phase transition pressures are equal to about 4.4 GPa and 2.6 GPa, according to the GGA and LDA calculations, respectively, which is in a good agreement with the experimental value. Theoretically estimated value of the pressure coefficient of the band-gap luminescence in zinc-blende structure is in very good agreement with that recently measured in the QDs structures. The calculated Debye temperature, elastic constants and specific heat capacity for the zinc-blend structure agree well with the experimental data; the data for the cinnabar phase are reported here for the first time to the best of the authors' knowledge. - Highlights: • Quenching of luminescence of CdTe quantum dots embedded in ZnTe is theoretically explained. • The theoretical calculation of elastic and thermodynamic properties of CdTe by two types of ab-initio methods. • Theoretical calculations of some optical properties of CdTe under pressure in zinc-blende and cinnabar phases
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Positron diffusion in zinc-blende-type semiconductors
International Nuclear Information System (INIS)
Singh, R.P.; Singh, M.
1992-01-01
A theory of positron diffusion in the presence of positron scattering with acoustic, piezoelectric-acoustic, and optical phonons in zinc-blende-type semiconductors is developed. The velocity-velocity correlation function is used to calculate the diffusion coefficient and the Green's function is used to calculate the correlation function. In this formulation the relaxation time automatically appears through the imaginary part of the self-energy. The effect of screening is included within the Thomas-Fermi approximation. The theory is used to calculate the energy relaxation time and diffusion length of positrons in GaAs. It is shown that the transverse and longitudinal phonons contribute almost the same amount towards the relaxation time in the piezoelectric-acoustic-phonon scattering of positrons. It is also found that the contribution of piezoelectric-acoustic-phonon scattering is about 10% to that of acoustic-phonon scattering at low temperatures. We obtained a fairly good agreement between our theory and experimental results available to us. It is found that optical-phonon scattering plays an important role in getting good agreement between theory and experiment at high temperatures
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Topological Phase Transitions in Zinc-Blende Semimetals Driven Exclusively by Electronic Temperature
Trushin, Egor; Görling, Andreas
2018-04-01
We show that electronic phase transitions in zinc-blende semimetals with quadratic band touching (QBT) at the center of the Brillouin zone, like GaBi, InBi, or HgTe, can occur exclusively due to a change of the electronic temperature without the need to involve structural transformations or electron-phonon coupling. The commonly used Kohn-Sham density-functional methods based on local and semilocal density functionals employing the local density approximation (LDA) or generalized gradient approximations (GGAs), however, are not capable of describing such phenomena because they lack an intrinsic temperature dependence and account for temperature only via the occupation of bands, which essentially leads only to a shift of the Fermi level without changing the shape or topology of bands. Kohn-Sham methods using the exact temperature-dependent exchange potential, not to be confused with the Hartree-Fock exchange potential, on the other hand, describe such phase transitions. A simple modeling of correlation effects can be achieved by screening of the exchange. In the considered zinc-blende compounds the QBT is unstable at low temperatures and a transition to electronic states without QBT takes place. In the case of HgTe and GaBi Weyl points of type I and type II, respectively, emerge during the transitions. This demonstrates that Kohn-Sham methods can describe such topological phase transitions provided they are based on functionals more accurate than those within the LDA or GGA. Moreover, the electronic temperature is identified as a handle to tune topological materials.
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Transparent indium zinc oxide thin films used in photovoltaic cells based on polymer blends
International Nuclear Information System (INIS)
Besleaga, Cristina; Ion, L.; Ghenescu, Veta; Socol, G.; Radu, A.; Arghir, Iulia; Florica, Camelia; Antohe, S.
2012-01-01
Indium zinc oxide (IZO) thin films were obtained using pulsed laser deposition. The samples were prepared by ablation of targets with In concentrations, In/(In + Zn), of 80 at.%, at low substrate temperatures under reactive atmosphere. IZO films were used as transparent electrodes in polymer-based – poly(3-hexylthiophene) and 1-(3-methoxycarbonyl)-propyl-1-phenyl-(6,6)C61 1:1 blend – photovoltaic cells. The action spectra measurements revealed that IZO-based photovoltaic structures have performances comparable with those using indium–tin–oxide as transparent electrode. - Highlights: ► Indium zinc oxide films were grown by pulsed laser deposition at room temperature. ► The films had large free carrier density and reasonably high mobility. ► These films fit for transparent electrodes in polymer-based photovoltaic cells.
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International Nuclear Information System (INIS)
Mizuguchi, Masaki; Akinaga, Hiro; Manago, Takashi; Ono, Kanta; Oshima, Masaharu; Shirai, Masafumi
2002-01-01
Epitaxial zinc-blende CrAs thin films were grown at two different temperatures. CrAs (2 nm) grown at 200 deg. C formed plateau-shapes, whereas CrAs (2 nm) grown at 300 deg. C formed dispersed dots. The thin film grown at 200 deg. C showed ferromagnetic behavior at room temperature, and the Curie temperature was estimated to be over 400 K
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Band offset in zinc oxy-sulfide/cubic-tin sulfide interface from X-ray photoelectron spectroscopy
Energy Technology Data Exchange (ETDEWEB)
Sanal, K.C.; Nair, P.K.; Nair, M.T.S., E-mail: mtsn@ier.unam.mx
2017-02-28
Highlights: • Zinc oxy-sulfide thin films, 175–240 nm, deposited by rf-sputtering from targets of ZnO + ZnS. • Oxygen content in thin films is enhanced 3–4 times compared with that in ZnO:ZnS targets. • Thin film ZnO{sub x}S{sub 1−x} with x = 0.88–0.27 and optical band gap 2.8–3.2 eV is suitable for solar cells. • The conduction band offset with SnS of cubic structure studied by XPS are +0.41 to −0.28 eV. - Abstract: Zinc oxy-sulfide, ZnO{sub x}S{sub 1−x}, has been found to provide better band alignment in thin film solar cells of tin sulfide of orthorhombic crystalline structure. Here we examine ZnO{sub x}S{sub 1−x}/SnS-CUB interface, in which the ZnO{sub x}S{sub 1−x} thin film was deposited by radio frequency (rf) magnetron sputtering on SnS thin film of cubic (CUB) crystalline structure with a band gap (E{sub g}) of 1.72 eV, obtained via chemical deposition. X-ray photoelectron spectroscopy provides the valence band maxima of the materials and hence places the conduction band offset of 0.41 eV for SnS-CUB/ZnO{sub 0.27}S{sub 0.73} and −0.28 eV for SnS-CUB/ZnO{sub 0.88}S{sub 0.12} interfaces. Thin films of ZnO{sub x}S{sub 1−x} with 175–240 nm in thickness were deposited from targets prepared with different ZnO to ZnS molar ratios. With the target of molar ratio of 1:13.4, the thin films are of composition ZnO{sub 0.27}S{sub 0.73} with hexagonal crystalline structure and with that of 1:1.7 ratio, it is ZnO{sub 0.88}S{sub 0.12}. The optical band gap of the ZnO{sub x}S{sub 1−x} thin films varies from 2.90 eV to 3.21 eV as the sulfur to zinc ratio in the film increases from 0.12:1 to 0.73:1 as determined from X-ray diffraction patterns. Thus, band offsets sought for absorber materials and zinc oxy-sulfide in solar cells may be achieved through a choice of ZnO:ZnS ratio in the sputtering target.
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Hexagonal (wurtzite) GaN inclusions as a defect in cubic (zinc-blende) GaN
International Nuclear Information System (INIS)
Zainal, N.; Novikov, S.V.; Akimov, A.V.; Staddon, C.R.; Foxon, C.T.; Kent, A.J.
2012-01-01
The dependence of the hexagonal fraction with thickness in MBE-grown bulk cubic (c-) GaN epilayer is presented in this paper. A number of c-GaN epilayers with different thicknesses were characterized via PL and XRD measurements. From the PL spectra, the signal due to h-GaN inclusions increases as the thickness of the c-GaN increases. On the contrary, in the XRD diffractogram, c-GaN shows a dominant signal at all thicknesses, and only a weak peak at ∼35° is observed in the diffractogram, implying the existence of a small amount of h-GaN in the c-GaN layer. The best quality of c-GaN is observed in the first 10 μm of GaN on the top of GaAs substrate. Even though the hexagonal content increases with the thickness, the average content remains below 20% in c-GaN layers up to 50 μm thick. The surface morphology of thick c-GaN is also presented.
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Ab initio study of phase transition of boron nitride between zinc-blende and rhombohedral structures
Energy Technology Data Exchange (ETDEWEB)
Nishida, S.; Funashima, H.; Sato, K.; Katayama-Yoshida, H. [Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan)
2013-12-04
Boron nitride has polymorphs such as zinc-blende (c-BN), wurtzite (w-BN), rhombohedral (r-BN), and graphite-like (h-BN) forms. We simulate the direct conversion of r-BN to c-BN through electronic excitation. In our calculation, the conversion is made possible by increasing the hole concentration to over 0.06/atom. This conversion should be experimentally possible by hole-doping via an electric double layer transistor (EDLT) or capacitor.
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Energy Technology Data Exchange (ETDEWEB)
Vannier, Aurore [Centre de Recherche et d' Etude sur les Procedes d' Ignifugation des Materiaux (CREPIM), Parc de la porte Nord, F-62200 Bruay-la-Buissiere (France); Duquesne, Sophie, E-mail: Sophie.duquesne@ensc-lille.fr [Laboratoire des Procedes d' Elaboration de Revetements Fonctionnels (PERF), UMR-CNRS 8008/LSPES - Ecole Nationale Superieure de Chimie de Lille, BP 90108, F-59652 Villeneuve d' Ascq (France); Bourbigot, Serge [Laboratoire des Procedes d' Elaboration de Revetements Fonctionnels (PERF), UMR-CNRS 8008/LSPES - Ecole Nationale Superieure de Chimie de Lille, BP 90108, F-59652 Villeneuve d' Ascq (France); Alongi, Jenny; Camino, Giovanni [Centro di Cultura per l' Ingegneria delle Materie Plastiche - Politechnico di Torino, V.le T. Michel, 5, 15100 Alessandria (Italy); Delobel, Rene [Centre de Recherche et d' Etude sur les Procedes d' Ignifugation des Materiaux (CREPIM), Parc de la porte Nord, F-62200 Bruay-la-Buissiere (France)
2009-11-10
The incorporation of both OMPOSS and Exolit OP950 (zinc phosphinate) into PET leads to increased fire retarding properties and a synergistic effect has been established between the three components. Here the thermal degradation of OMPOSS, Exolit OP950, PET and blends of them is investigated via thermal degradation in pyrolytic and thermo-oxidative conditions. All species formed during the degradation of the additives or the blends are identified by solid state NMR and X-ray diffraction in the condensed phase and by GC-MS in the gas phase. The investigation shows that no chemical interaction occurs between the additives, which suggests that the synergy responsible for the improvement of fire properties of the material has a physical origin.
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International Nuclear Information System (INIS)
Vannier, Aurore; Duquesne, Sophie; Bourbigot, Serge; Alongi, Jenny; Camino, Giovanni; Delobel, Rene
2009-01-01
The incorporation of both OMPOSS and Exolit OP950 (zinc phosphinate) into PET leads to increased fire retarding properties and a synergistic effect has been established between the three components. Here the thermal degradation of OMPOSS, Exolit OP950, PET and blends of them is investigated via thermal degradation in pyrolytic and thermo-oxidative conditions. All species formed during the degradation of the additives or the blends are identified by solid state NMR and X-ray diffraction in the condensed phase and by GC-MS in the gas phase. The investigation shows that no chemical interaction occurs between the additives, which suggests that the synergy responsible for the improvement of fire properties of the material has a physical origin.
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Energy Technology Data Exchange (ETDEWEB)
Abdiche, A., E-mail: abdiche_a@yahoo.fr [Engineering Physics Laboratory, Tiaret University, 14000 Tiaret (Algeria); Baghdad, R. [Engineering Physics Laboratory, Tiaret University, 14000 Tiaret (Algeria); Khenata, R., E-mail: khenata_rabah@yahoo.fr [Laboratoire de Physique Quantique et de Modelisation Mathematique (LPQ3M), Departement de Technologie, Universite de Mascara, 29000 Mascara (Algeria); Department of Physics and Astronomy, King Saud University, P.O Box 2455, Riyadh 11451 (Saudi Arabia); Riane, R. [Computational Materials Science Laboratory, University Research of Sidi-Bel-Abbes, 22000 Algeria (Algeria); Al-Douri, Y. [Institute of Nono Electronic Engineering, University Malaysia Perlis, 01000 Kangar, Perlis (Malaysia); Guemou, M. [Engineering Physics Laboratory, Tiaret University, 14000 Tiaret (Algeria); Bin-Omran, S. [Department of Physics and Astronomy, King Saud University, P.O Box 2455, Riyadh 11451 (Saudi Arabia)
2012-02-01
The structural and electronic properties of cubic zinc blende BN, BP, AlN and AlP compounds and their B{sub x}Al{sub 1-x}N{sub y}P{sub 1-y} quaternary alloys, have been calculated using the non relativistic full-potential linearized-augmented plane wave FP-LAPW method. The exchange-correlation potential is treated with the local density approximation of Perdew and Wang (LDA-PW) as well as the generalized gradient approximation (GGA) of Perdew-Burke and Ernzerhof (GGA-PBE). The calculated structural properties of BN, BP, AlN and AlP compounds are in good agreement with the available experimental and theoretical data. A nonlinear variation of compositions x and y with the lattice constants, bulk modulus, direct and indirect band gaps is found. The calculated bowing of the fundamental band gaps is in good agreement with the available experimental and theoretical value. To our knowledge this is the first quantitative theoretical investigation on B{sub x}Al{sub 1-x}N{sub y}P{sub 1-y} quaternary alloy and still awaits experimental confirmations.
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International Nuclear Information System (INIS)
Feng Shi-Quan; Li Jun-Yu; Cheng Xin-Lu
2015-01-01
The structural, dielectric, lattice dynamical and thermodynamic properties of zinc-blende CdX (X=S, Se, Te) are studied by using a plane-wave pseudopotential method within the density-functional theory. Our calculated lattice constants and bulk modulus are compared with the published experimental and theoretical data. In addition, the Born effective charges, electronic dielectric tensors, phonon frequencies, and longitudinal optical-transverse optical splitting are calculated by the linear-response approach. Some of the characteristics of the phonon-dispersion curves for zinc-blende CdX (X=S, Se, Te) are summarized. What is more, based on the lattice dynamical properties, we investigate the thermodynamic properties of CdX (X=S, Se, Te) and analyze the temperature dependences of the Helmholtz free energy F, the internal energy E, the entropy S and the constant-volume specific heat C_v. The results show that the heat capacities for CdTe, CdSe, and CdS approach approximately to the Petit-Dulong limit 6R. (paper)
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International Nuclear Information System (INIS)
Wang Huanyou; Xu Hui; Wang Xianchun; Jiang Chunzhi
2009-01-01
The density function perturbation theory (DFPT) is employed to study the lattice dynamics and thermodynamic properties (with quasiharmonic approximation) of zinc-blende BN. First we discuss the structural properties and compare the phonon spectrum with available Raman scattering experiments. Thereafter using the calculated phonon dispersions we obtain the PTV equation of state from the free energy. Our results for the above properties are generally speaking in good agreement with experiments and with similar theoretical calculations. Owing to the anharmonic effect at high temperature, the calculated linear thermal expansion coefficients (CTE) are low to experimental data.
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Energy Technology Data Exchange (ETDEWEB)
Chen, Yukun, E-mail: cyk@scut.edu.cn [The Key Laboratory of Polymer Processing Engineering, Ministry of Education, South China University of Technology, Guangzhou 510640 (China); School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640 (China); Xu, Chuanhui [College of Material Science and Engineering, South China University of Technology, Guangzhou 510640 (China); Cao, Liming [The Key Laboratory of Polymer Processing Engineering, Ministry of Education, South China University of Technology, Guangzhou 510640 (China); School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640 (China); Cao, Xiaodong [College of Material Science and Engineering, South China University of Technology, Guangzhou 510640 (China)
2013-02-15
Polypropylene (PP)/ethylene–propylene-diene monomer (EPDM)/zinc dimethacrylate (ZDMA) blends with remarkable toughness and extensibility were successfully prepared via peroxide dynamical vulcanization. A unique structure with the EPDM particles surrounded by a transition zone containing numerous polymerized ZDMA (PZDMA) nano-particles was observed for the first time by using transmission electron microscopy (TEM) examination, which contributed to the dramatically increase of Izod impact strength. Dynamic mechanical analysis (DMA) confirmed that the possible PZDMA graft products resulted from peroxide dynamical vulcanization improved the compatibility between EPDM and PP phases. The specific morphology of the PP/EPDM/ZDMA blends indicated that ZDMA can lead to size reduction and good distribution uniformity of the crosslinked rubber particles and the increase of adhesion between PP matrix and EPDM phases during deformation. The synergic effect of the increase in the effective volume of the EPDM phase, the improved compatibility and adhesion between EPDM and PP phases and the deformation of those fine rubber particles is believed to result in the remarkable high toughness and extensibility of the PP/EPDM/ZDMA blends. Particularly for the PP/EPDM ratio of 70/30, the PP/EPDM/ZDMA (70/30/9, w/w/w) ternary blends with the Izod impact strength nearly 2 times higher than PP/EPDM (70/30, w/w) binary blends and 15–20 times higher than PP are achieved; besides, the elongation at break of PP/EPDM/ZDMA ternary blends is 4–5 times higher than that of PP/EPDM binary blends. - Highlights: ► ZDMA largely toughen peroxide dynamically vulcanized PP/EPDM blend. ► PZDMA graft products improved the compatibility and adhesion between EPDM and PP. ► Size reduction and good distribution uniformity of crosslinked rubber particles.
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International Nuclear Information System (INIS)
Chen, Yukun; Xu, Chuanhui; Cao, Liming; Cao, Xiaodong
2013-01-01
Polypropylene (PP)/ethylene–propylene-diene monomer (EPDM)/zinc dimethacrylate (ZDMA) blends with remarkable toughness and extensibility were successfully prepared via peroxide dynamical vulcanization. A unique structure with the EPDM particles surrounded by a transition zone containing numerous polymerized ZDMA (PZDMA) nano-particles was observed for the first time by using transmission electron microscopy (TEM) examination, which contributed to the dramatically increase of Izod impact strength. Dynamic mechanical analysis (DMA) confirmed that the possible PZDMA graft products resulted from peroxide dynamical vulcanization improved the compatibility between EPDM and PP phases. The specific morphology of the PP/EPDM/ZDMA blends indicated that ZDMA can lead to size reduction and good distribution uniformity of the crosslinked rubber particles and the increase of adhesion between PP matrix and EPDM phases during deformation. The synergic effect of the increase in the effective volume of the EPDM phase, the improved compatibility and adhesion between EPDM and PP phases and the deformation of those fine rubber particles is believed to result in the remarkable high toughness and extensibility of the PP/EPDM/ZDMA blends. Particularly for the PP/EPDM ratio of 70/30, the PP/EPDM/ZDMA (70/30/9, w/w/w) ternary blends with the Izod impact strength nearly 2 times higher than PP/EPDM (70/30, w/w) binary blends and 15–20 times higher than PP are achieved; besides, the elongation at break of PP/EPDM/ZDMA ternary blends is 4–5 times higher than that of PP/EPDM binary blends. - Highlights: ► ZDMA largely toughen peroxide dynamically vulcanized PP/EPDM blend. ► PZDMA graft products improved the compatibility and adhesion between EPDM and PP. ► Size reduction and good distribution uniformity of crosslinked rubber particles
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The computational design of zinc-blende half-metals and their nanostructures
International Nuclear Information System (INIS)
Shirai, Masafumi
2004-01-01
The influence of atomic disorder and heterointerfaces with III-V semiconductors on the electronic and magnetic properties of zinc-blende (ZB) CrAs is studied by ab initio calculations based on density-functional theory. Antisite Cr spins are coupled antiferromagnetically with the Cr spins at the ordinary sites, while the ferromagnetic coupling between the Cr spins at the ordinary sites is robust against defect formation. The degree of spin polarization is not reduced significantly by the impurity bands formed in the minority spin energy gap. In the ZB CrAs/GaAs junction, relatively high spin polarization is retained even at the interface in contrast to usual half-metal/semiconductor heterojunctions. Complete spin polarization is also preserved throughout ZB CrAs/GaAs multilayers and it is insensitive to the substitutional disorder between Cr and Ga sites
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International Nuclear Information System (INIS)
Li, Lin; Zhang, Jin; Jo, Jae Ok; Datta, Sanjoy; Kim, Jin Kuk
2013-01-01
Highlights: ► A (90:10) blend of CIIR and ENR by weight was used as the base. ► Different process oil and ZnO were used to optimize the gas barrier property. ► The minimum oxygen permeability is obtained using sheet ZnO. - Abstract: In many polymer applications such as inner tire liners and fuel hoses, imparting excellent gas barrier property is of prime importance. Researches in this direction had been done based on a judicious choice of polymer type or a blend thereof and the compounding ingredients. Though butyl rubber has been the polymer of choice because of its excellent gas barrier property, yet researches were targeted to improve the same with further modification in the polymer type and variation in compounding ingredients. In this study, a (90:10) blend of chlorobutyl rubber (CIIR) and Epoxdised Natural Rubber (ENR) by weight was used as the base. Four different types of process oil and three different types of zinc oxide (ZnO) at fixed predetermined concentrations were used to optimize the gas barrier and mechanical properties. In this blend, recycled aromatic oil (RAE) and sheet zinc oxide were effective in imparting the best overall combination of properties. Scanning Electron Microscopic (SEM) studies of ZnO were done to understand the structure property relationship
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Synthesis and photoluminescence of a full zinc blende phase ZnO nanorod array
International Nuclear Information System (INIS)
Zhou Shaomin; Gong Hechun; Zhang Bin; Du Zuliang; Zhang Xingtang; Wu Sixin
2008-01-01
A single-crystalline ZnO nanorod array with rectangular cross-sections has been synthesized, in which the as-obtained products are a complete metastable zinc blende (ZB) phase. X-ray powder diffraction, electron microscopy, and elemental maps have been used to show that the ZB-ZnO samples have a lattice constant a = 4.580 A, and are free from contamination by hexagonal wurtzite (HW) ZnO. Based on our experimental data, the associated growth mechanism is tentatively suggested. In addition, the photoluminescence (PL) spectrum (about 400 nm (3.1 eV)) of the as-fabricated ZB-ZnO products was detected; this is the first experimental report of the optical properties of ZB-ZnO nanorod arrays
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Strain effects in polytypical wurtzite/zinc-blend nanowhiskers
Sipahi, Guilherme; Faria, Paulo
2012-02-01
The recent interest on III-V nanowhiskers has led to the growth of high quality samples of systems with two different crystalline structures [1]. The crystals grown in [111]-direction for the zinc-blend (ZB) phase and [0001]-direction for the wurtzite (WZ) phase are very similar and can both be described as stacked hexagonal layers. The effect of two different structural phases coexisting in the same nanostrucure is known as polytypism and creates confinement profiles similar to a heterostructure. One can notice band offsets at the interface and the formation of electronic minibands that can be explored to design systems for device applications. Although some of the III-V compounds do not present WZ structure in bulk form, recent calculations [2] presented a theoretical prediction of their band structure. However, as they considered that ZB and WZ to have the same lattice parameters no strain effects should appear on a first approach. Our theoretical approach introduces strain effects in our previous model [3] by using group theory arguments. It allows the analysis of the biaxial strain effects for both structures in a single matrix. [1] P. Caroff et al. Nature Nanotech. 4, 50, 2009. [2] A. De and C. E. Pryor, Phys. Rev. B 81, 155210, 2010 [3] http://arxiv.org/abs/1012.022
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Efficient n-type doping of zinc-blende III-V semiconductor nanowires
Besteiro, Lucas V.; Tortajada, Luis; Souto, J.; Gallego, L. J.; Chelikowsky, James R.; Alemany, M. M. G.
2014-03-01
We demonstrate that it is preferable to dope III-V semiconductor nanowires by n-type anion substitution as opposed to cation substitution. Specifically, we show the dopability of zinc-blende nanowires is more efficient when the dopants are placed at the anion site as quantified by formation energies and the stabilization of DX-like defect centers. The comparison with previous work on n - type III-V semiconductor nanocrystals also allows to determine the role of dimensionality and quantum confinement on doping characteristics of materials. Our results are based on first-principles calculations of InP nanowires by using the PARSEC code. Work supported by the Spanish MICINN (FIS2012-33126) and Xunta de Galicia (GPC2013-043) in conjunction with FEDER. JRC acknowledges support from DoE (DE-FG02-06ER46286 and DESC0008877). Computational support was provided in part by CESGA.
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Karthik, N.; Goldwin Xavier, X.; Rajasekar, R.; Ganesh Bairavan, P.; Dhanseelan, S.
2017-05-01
Present study provides the effect of Zinc Oxide (ZnO) and Cerium Oxide (CeO2) nanoparticles additives on the Performance and emission uniqueness of Jatropha. Jatropha blended fuel is prepared by the emulsification technique with assist of mechanical agitator. Nano particles (Zinc Oxide (ZnO)) and Cerium Oxide (CeO2)) mixed with Jatropha blended fuel in mass fraction (100 ppm) with assist of an ultrasonicator. Experiments were conducted in single cylinder constant speed direct injection diesel engine for various test fuels. Performance results revealed that Brake Thermal Efficiency (BTE) of Jatropha blended Cerium Oxide (B20CE) is 3% and 11% higher than Jatropha blended zinc oxide (B20ZO) and Jatropha blended fuel (B20) and 4% lower than diesel fuel (D100) at full load conditions. Emission result shows that HC and CO emissions of Jatropha blended Cerium Oxide (B20CE) are (6%, 22%, 11% and 6%, 15%, 12%) less compared with Jatropha blended Zinc Oxide (B20ZO), diesel (D100) and Jatropha blended fuel (B20) at full load conditions. NOx emissions of Jatropha blended Cerium Oxide is 1 % higher than diesel fuel (D100) and 2% and 5% lower than Jatropha blended Zinc Oxide, and jatropha blended fuel.
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The lattice distortion effect for zinc-blende CrAs and CrSb
International Nuclear Information System (INIS)
Yamana, Keita; Geshi, Masaaki; Tsukamoto, Hidekazu; Uchida, Ichiro; Shirai, Masafumi; Kusakabe, Koichi; Suzuki, Naoshi
2004-01-01
We investigated the stability of the ferromagnetism of CrAs and CrSb in the zinc-blende structure against the lattice distortion, systematically. A calculation within the generalized gradient approximation using a full potential linearized augmented plane wave method was performed. We compared the ferromagnetic state and the antiferromagnetic state assuming tetragonal distortion with the lattice constants a and c changing independently and determined the spin polarization ratio in the ferromagnetic phase. The result shows that complete spin polarization (half-metallic ferromagnetism) remains stable even in the presence of large tetragonal distortion. On the other hand, our calculation shows that two monolayers of CrAs is enough to produce a half-metallic state in the CrAs/GaAs multilayer. Thus, the present result suggests that the half-metallic nature persists in various atomic-scale superlattices made of distorted CrAs or CrSb
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Magnetoconductance correction in zinc-blende semiconductor nanowires with spin-orbit coupling
Kammermeier, Michael; Wenk, Paul; Schliemann, John; Heedt, Sebastian; Gerster, Thomas; Schäpers, Thomas
2017-12-01
We study the effects of spin-orbit coupling on the magnetoconductivity in diffusive cylindrical semiconductor nanowires. Following up on our former study on tubular semiconductor nanowires, we focus in this paper on nanowire systems where no surface accumulation layer is formed but instead the electron wave function extends over the entire cross section. We take into account the Dresselhaus spin-orbit coupling resulting from a zinc-blende lattice and the Rashba spin-orbit coupling, which is controlled by a lateral gate electrode. The spin relaxation rate due to Dresselhaus spin-orbit coupling is found to depend neither on the spin density component nor on the wire growth direction and is unaffected by the radial boundary. In contrast, the Rashba spin relaxation rate is strongly reduced for a wire radius that is smaller than the spin precession length. The derived model is fitted to the data of magnetoconductance measurements of a heavily doped back-gated InAs nanowire and transport parameters are extracted. At last, we compare our results to previous theoretical and experimental studies and discuss the occurring discrepancies.
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International Nuclear Information System (INIS)
Pizani, P S; Jasinevicius, R G
2014-01-01
Raman scattering was employed to study structural phase transitions of InSb, GaSb and GaAs induced by highly non-hydrostatic pressures applied by mechanical impact, in which high compression/decompression rates are imposed to the sample. The results showed that is possible to produce several structural phases localized in different micrometric regions of the same sample: the zinc blende to possibly wurtzite structural phase transition and the generation of a multiphase state.
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Ab initio calculations of the magnetic properties of TM (Ti, V)-doped zinc-blende ZnO
Goumrhar, F.; Bahmad, L.; Mounkachi, O.; Benyoussef, A.
2018-01-01
In order to promote suitable material to be used in spintronics devices, this study purposes to evaluate the magnetic properties of the titanium and vanadium-doped zinc-blende ZnO from first-principles. The calculations of these properties are based on the Korringa-Kohn-Rostoker (KKR) method combined with the coherent potential approximation (CPA), using the local density approximation (LDA). We have calculated and discussed the density of states (DOSs) in the energy phase diagrams for different concentration values, of the dopants. We have also investigated the magnetic and half-metallic properties of this doped compound. Additionally, we showed the mechanism of the exchange coupling interaction. Finally, we estimated and studied the Curie temperature for different concentrations.
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Blending Of Radioactive Salt Solutions In Million Gallon Tanks
Energy Technology Data Exchange (ETDEWEB)
Leishear, Robert A.; Lee, Si Y.; Fowley, Mark D.; Poirier, Michael R.
2012-12-10
Research was completed at Savannah River National Laboratory (SRNL) to investigate processes related to the blending of radioactive, liquid waste, salt solutions in 4920 cubic meter, 25.9 meter diameter storage tanks. One process was the blending of large salt solution batches (up to 1135 ? 3028 cubic meters), using submerged centrifugal pumps. A second process was the disturbance of a settled layer of solids, or sludge, on the tank bottom. And a third investigated process was the settling rate of sludge solids if suspended into slurries by the blending pump. To investigate these processes, experiments, CFD models (computational fluid dynamics), and theory were applied. Experiments were performed using simulated, non-radioactive, salt solutions referred to as supernates, and a layer of settled solids referred to as sludge. Blending experiments were performed in a 2.44 meter diameter pilot scale tank, and flow rate measurements and settling tests were performed at both pilot scale and full scale. A summary of the research is presented here to demonstrate the adage that, ?One good experiment fixes a lot of good theory?. Experimental testing was required to benchmark CFD models, or the models would have been incorrectly used. In fact, CFD safety factors were established by this research to predict full-scale blending performance. CFD models were used to determine pump design requirements, predict blending times, and cut costs several million dollars by reducing the number of required blending pumps. This research contributed to DOE missions to permanently close the remaining 47 of 51 SRS waste storage tanks.
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Energy Technology Data Exchange (ETDEWEB)
Verma, U. P.; Nayak, V. [School of Studies in Phyics, jiwaji University, Gwalior-474011 (India)
2016-05-23
Quantum mechanical first principle calculations have been performed to study the electronic and structural properties of TiN and TiAs in zinc blende (ZB) and rock salt (RS) structures. The full-potential linearized augmented plane wave (FP-LAPW) method has been used within the framework of density functional theory (DFT). The exchange correlation functional has been solved employing generalized gradient approximation (GGA). Our predicted results for lattice constants are in good agreement with the earlier findings. The electronic band structures of TiX are metallic in both the phases.
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Blending of Radioactive Salt Solutions in Million Gallon Tanks - 13002
International Nuclear Information System (INIS)
Leishear, Robert A.; Lee, Si Y.; Fowley, Mark D.; Poirier, Michael R.
2013-01-01
Research was completed at Savannah River National Laboratory (SRNL) to investigate processes related to the blending of radioactive, liquid waste, salt solutions in 4920 cubic meter, 25.9 meter diameter storage tanks. One process was the blending of large salt solution batches (up to 1135 - 3028 cubic meters), using submerged centrifugal pumps. A second process was the disturbance of a settled layer of solids, or sludge, on the tank bottom. And a third investigated process was the settling rate of sludge solids if suspended into slurries by the blending pump. To investigate these processes, experiments, CFD models (computational fluid dynamics), and theory were applied. Experiments were performed using simulated, non-radioactive, salt solutions referred to as supernates, and a layer of settled solids referred to as sludge. Blending experiments were performed in a 2.44 meter diameter pilot scale tank, and flow rate measurements and settling tests were performed at both pilot scale and full scale. A summary of the research is presented here to demonstrate the adage that, 'One good experiment fixes a lot of good theory'. Experimental testing was required to benchmark CFD models, or the models would have been incorrectly used. In fact, CFD safety factors were established by this research to predict full-scale blending performance. CFD models were used to determine pump design requirements, predict blending times, and cut costs several million dollars by reducing the number of required blending pumps. This research contributed to DOE missions to permanently close the remaining 47 of 51 SRS waste storage tanks. (authors)
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Blending of Radioactive Salt Solutions in Million Gallon Tanks - 13002
Energy Technology Data Exchange (ETDEWEB)
Leishear, Robert A.; Lee, Si Y.; Fowley, Mark D.; Poirier, Michael R. [Savannah River National Laboratory, Aiken. S.C., 29808 (United States)
2013-07-01
Research was completed at Savannah River National Laboratory (SRNL) to investigate processes related to the blending of radioactive, liquid waste, salt solutions in 4920 cubic meter, 25.9 meter diameter storage tanks. One process was the blending of large salt solution batches (up to 1135 - 3028 cubic meters), using submerged centrifugal pumps. A second process was the disturbance of a settled layer of solids, or sludge, on the tank bottom. And a third investigated process was the settling rate of sludge solids if suspended into slurries by the blending pump. To investigate these processes, experiments, CFD models (computational fluid dynamics), and theory were applied. Experiments were performed using simulated, non-radioactive, salt solutions referred to as supernates, and a layer of settled solids referred to as sludge. Blending experiments were performed in a 2.44 meter diameter pilot scale tank, and flow rate measurements and settling tests were performed at both pilot scale and full scale. A summary of the research is presented here to demonstrate the adage that, 'One good experiment fixes a lot of good theory'. Experimental testing was required to benchmark CFD models, or the models would have been incorrectly used. In fact, CFD safety factors were established by this research to predict full-scale blending performance. CFD models were used to determine pump design requirements, predict blending times, and cut costs several million dollars by reducing the number of required blending pumps. This research contributed to DOE missions to permanently close the remaining 47 of 51 SRS waste storage tanks. (authors)
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First-principles calculation on dilute magnetic alloys in zinc blend crystal structure
International Nuclear Information System (INIS)
Ullah, Hamid; Inayat, Kalsoom; Khan, S.A; Mohammad, S.; Ali, A.; Alahmed, Z.A.; Reshak, A.H.
2015-01-01
Ab-initio calculations are performed to investigate the structural, electronic and magnetic properties of spin-polarized diluted magnetic alloys in zinc blende structure. The first-principles study is carried out on Mn doped III–V semiconductors. The calculated band structures, electronic properties and magnetic properties of Ga 1−x Mn x X (X=P, As) compounds reveal that Ga 0.75 Mn 0.25 P is half metallic turned to be metallic with increasing x to 0.5 and 0.75, whereas substitute P by As cause to maintain the half-metallicity nature in both of Ga 0.75 Mn 0.25 As and Ga 0.5 Mn 0.5 As and tune Ga 0.25 Mn 0.75 As to be metallic. Calculated total magnetic moments and the robustness of half-metallicity of Ga 0.75 Mn 0.25 P, Ga 0.75 Mn 0.25 As and Ga 0.5 Mn 0.5 As with respect to the variation in lattice parameters are also discussed. The predicted theoretical evidence shows that some Mn-doped III–V semiconductors can be effectively used in spintronic devices
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Kozlenko, D P; Ehm, L; Knorr, K; Hull, S; Shchennikov, V V; Voronin, V I
2002-01-01
The structure of the pseudo-binary mercury chalcogenide alloy HgSe_{0.7}S_{0.3} has been studied by means of X-ray and neutron powder diffraction at pressure up to 8.5 GPa. A phase transition from the cubic zinc blende structure to the hexagonal cinnabar structure was observed at P{\\sim}1 GPa. The obtained structural parameters were used for the analysis of the geometrical relationship between the zinc blende and the cinnabar phases. The zinc blende-cinnabar phase transition is discussed in the framework of Landau theory of the phase transitions. It was found that the possible order parameter for the structural transformation is the spontaneous strain e_{4}. This assignment agrees with previously observed high pressure behaviour of the elastic constants of other mercury chalcogenides.
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A structural study of the pseudo-binary mercury chalcogenide alloy HgSe0.7S0.3 at high pressure
International Nuclear Information System (INIS)
Kozlenko, D.P.; Savenko, B.N.; Ehm, L.; Knorr, K.; Hull, S.; Shchennikov, V.V.; Voronin, V.I.
2002-01-01
The structure of the pseudo-binary mercury chalcogenide alloy HgSe 0.7 S 0.3 has been studied by means of X-ray and neutron powder diffraction at pressure up to 8.5 GPa. A phase transition from the cubic zinc blende structure to the hexagonal cinnabar structure was observed at P∼1 GPa. The obtained structural parameters were used for the analysis of the geometrical relationship between the zinc blende and the cinnabar phases. The zinc blende-cinnabar phase transition is discussed in the framework of the Landau theory of phase transitions. It was found that the possible order parameter for the structural transformation is the spontaneous strain e 4 . This assignment agrees with previously observed high pressure behaviour of the elastic constants of other mercury chalcogenides
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ab initio and experimental investigations
Indian Academy of Sciences (India)
19
a Laboratoire de Magnétisme et de Physique des Hautes Energies Département .... ZnO exists in hexagonal wurtzite or cubic zinc blende structures. ..... The determination of lattice parameters, strain and crystallite size has been achieved by.
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International Nuclear Information System (INIS)
Hsiao, C.-L.; Wu, C.-T.; Hsu, H.-C.; Hsu, G.-M.; Chen, L.-C.; Liu, T.-W.; Shiao, W.-Y.; Yang, C. C.; Gaellstroem, Andreas; Holtz, Per-Olof; Chen, C.-C.; Chen, K.-H.
2008-01-01
High-phase-purity zinc-blende (zb) InN thin film has been grown by plasma-assisted molecular-beam epitaxy on r-plane sapphire substrate pretreated with nitridation. X-ray diffraction analysis shows that the phase of the InN films changes from wurtzite (w) InN to a mixture of w-InN and zb-InN, to zb-InN with increasing nitridation time. High-resolution transmission electron microscopy reveals an ultrathin crystallized interlayer produced by substrate nitridation, which plays an important role in controlling the InN phase. Photoluminescence emission of zb-InN measured at 20 K shows a peak at a very low energy, 0.636 eV, and an absorption edge at ∼0.62 eV is observed at 2 K, which is the lowest bandgap reported to date among the III-nitride semiconductors
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Tailoring ferromagnetism in chromium-doped zinc oxide
Haq, Bakhtiar Ul
2014-03-11
The simultaneous manipulation of both charge and spin has made diluted magnetic semiconductors (DMS) a potential material for the fabrication of spintronic devices. We report DMSs based on ZnO doped with Cr in wurtzite (WZ) and zinc-blend (ZB) geometries. The injection of Cr impurities at a concentration of 6.25% has successfully tuned ferromagnetism in ZnO. To recognize the nature of magnetic interactions, two spatial configurations are investigated, where the impurity atoms are placed at minimum and maximum separation distances. The material favors the short-range magnetic coupling and has a tendency towards Cr clustering. The injection of a Cr impurity into ZnO strongly influences the electronic properties in terms of band structure, dependent on the impurity spatial distribution. It is half metallic for both structural geometries when impurity atoms have minimum separation and is metallic when they are placed far apart. Moreover, replacing Zn with Cr does not show a significant effect on the structural geometries. Our results endorse that Cr:ZnO can be efficiently used for spin-polarized transport and other spin-dependent applications in both hexagonal and cubic phases.
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Green–white electroluminescence and green photoluminescence of zinc complexes
Energy Technology Data Exchange (ETDEWEB)
Janghouri, Mohammad; Mohajerani, Ezeddin [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran 1983963113 (Iran, Islamic Republic of); Amini, Mostafa M.; Najafi, Ezzatollah [Department of Chemistry, Shahid Beheshti University, G.C., Tehran 1983963113 (Iran, Islamic Republic of)
2014-10-15
A series of zinc complexes has been synthesized and utilized as fluorescent materials in organic light-emitting diodes (OLEDs). All prepared complexes were characterized by elemental analysis (CHN), UV–vis, FT-IR and {sup 1}H NMR spectroscopy. The energy levels of zinc complexes were determined by cyclic voltammetry measurements. Devices with fundamental structure of ITO/PVK:PBD (50 nm)/zinc complexes/BCP (5 nm)/Alq{sub 3} (25 nm)/Al (180 nm) were fabricated. A green electroluminescence was obtained from thin film complexes at 25 nm thickness. When thickness of the complex bis(2-methylquinolin-8-olato)-bis[(acetato)-(methanol)zinc(II)] (B) in thin film decreased from 25 nm to 20, 18, and 12 nm, a white electroluminescence obtained. The white emission which was composed of blue and green attributed to the PVK:PBD blend and thickness of complex, respectively. With 12 nm thickness of complex, a maximum luminance of 4530 cd/m{sup 2} at a current density 398.32 mA/cm{sup 2} with CIE coordinates of 0.22 and 0.36 at 20 V was achieved. - Highlights: • Several new zinc complexes have been synthesized and utilized as fluorescent materials in OLEDs. • Photoluminescence emission of zinc complexes showed a red shift in respect to PVK:PBD blend. • Green electroluminescence emission from zinc complexes was achieved. • White emission has been obtained for an OLED by changing thickness of the zinc complex.
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Green–white electroluminescence and green photoluminescence of zinc complexes
International Nuclear Information System (INIS)
Janghouri, Mohammad; Mohajerani, Ezeddin; Amini, Mostafa M.; Najafi, Ezzatollah
2014-01-01
A series of zinc complexes has been synthesized and utilized as fluorescent materials in organic light-emitting diodes (OLEDs). All prepared complexes were characterized by elemental analysis (CHN), UV–vis, FT-IR and 1 H NMR spectroscopy. The energy levels of zinc complexes were determined by cyclic voltammetry measurements. Devices with fundamental structure of ITO/PVK:PBD (50 nm)/zinc complexes/BCP (5 nm)/Alq 3 (25 nm)/Al (180 nm) were fabricated. A green electroluminescence was obtained from thin film complexes at 25 nm thickness. When thickness of the complex bis(2-methylquinolin-8-olato)-bis[(acetato)-(methanol)zinc(II)] (B) in thin film decreased from 25 nm to 20, 18, and 12 nm, a white electroluminescence obtained. The white emission which was composed of blue and green attributed to the PVK:PBD blend and thickness of complex, respectively. With 12 nm thickness of complex, a maximum luminance of 4530 cd/m 2 at a current density 398.32 mA/cm 2 with CIE coordinates of 0.22 and 0.36 at 20 V was achieved. - Highlights: • Several new zinc complexes have been synthesized and utilized as fluorescent materials in OLEDs. • Photoluminescence emission of zinc complexes showed a red shift in respect to PVK:PBD blend. • Green electroluminescence emission from zinc complexes was achieved. • White emission has been obtained for an OLED by changing thickness of the zinc complex
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Kozlenko, D P; Hull, S; Knorr, K; Savenko, B N; Shchennikov, V V; Voronin, V I
2002-01-01
The structure of the pseudo-binary mercury chalcogenide alloy HgSe sub 0 sub . sub 7 S sub 0 sub . sub 3 has been studied by means of X-ray and neutron powder diffraction at pressure up to 8.5 GPa. A phase transition from the cubic zinc blende structure to the hexagonal cinnabar structure was observed at P approx 1 GPa. The obtained structural parameters were used for the analysis of the geometrical relationship between the zinc blende and the cinnabar phases. The zinc blende-cinnabar phase transition is discussed in the framework of the Landau theory of phase transitions. It was found that the possible order parameter for the structural transformation is the spontaneous strain e sub 4. This assignment agrees with previously observed high pressure behaviour of the elastic constants of other mercury chalcogenides
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New spintronic superlattices composed of half-metallic compounds with zinc-blende structure
International Nuclear Information System (INIS)
Fong, C Y; Qian, M C
2004-01-01
The successful growth of zinc-blende half-metallic compounds, namely CrAs and CrSb, in thin film forms offers a new direction to search for novel spintronic materials. By using a well documented first-principles algorithm, the VASP code, we predict the electronic and magnetic properties of superlattices made of these exciting half-metallic materials. Not only are the superlattices constructed with two of the half-metallic compounds (CrAs/MnAs) but also they are modelled to combine with both a III-V (GaAs-MnAs/CrAs/GaAs) and a IV-IV (MnC/SiC) semiconductor. We investigate variable thicknesses for the combinations. For every case, we find the equilibrium lattice constant as well as the lattice constant at which the superlattice exhibits the half-metallic properties. For CrAs/MnAs, the half-metallic properties are presented and the magnetic moments are shown to be the sum of the moments for MnAs and CrAs. The half-metallic properties of GaAs-MnAs/CrAs/GaAs are found to be crucially dependent on the completion of the d-p hybridization. The magnetic properties of MnC/SiC are discussed with respect to the properties of MnC
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First-principles calculation on dilute magnetic alloys in zinc blend crystal structure
Energy Technology Data Exchange (ETDEWEB)
Ullah, Hamid, E-mail: hamidullah@yahoo.com [Department of Physics, Government Post Graduate Jahanzeb College, Saidu Sharif Swat (Pakistan); Inayat, Kalsoom [Department of Physics, Government Post Graduate Jahanzeb College, Saidu Sharif Swat (Pakistan); Khan, S.A; Mohammad, S. [Department of Physics, Materials Modeling Laboratory, Hazara University, Mansehra 21300 (Pakistan); Ali, A. [Department of Advanced Materials Science & Engineering, Hanseo University, Seosan-si, Chungnam-do 356-706 (Korea, Republic of); Alahmed, Z.A. [Department of Physics and Astronomy, King Saud University, Riyadh 11451 (Saudi Arabia); Reshak, A.H. [New Technologies-Research Center, University of West Bohemia, Univerzitni 8, 306 14 Pilsen (Czech Republic); Center of Excellence Geopolymer and Green Technology, School of Material Engineering, University Malaysia Perlis, 01007 Kangar, Perlis (Malaysia)
2015-07-01
Ab-initio calculations are performed to investigate the structural, electronic and magnetic properties of spin-polarized diluted magnetic alloys in zinc blende structure. The first-principles study is carried out on Mn doped III–V semiconductors. The calculated band structures, electronic properties and magnetic properties of Ga{sub 1−x}Mn{sub x}X (X=P, As) compounds reveal that Ga{sub 0.75}Mn{sub 0.25}P is half metallic turned to be metallic with increasing x to 0.5 and 0.75, whereas substitute P by As cause to maintain the half-metallicity nature in both of Ga{sub 0.75}Mn{sub 0.25}As and Ga{sub 0.5}Mn{sub 0.5}As and tune Ga{sub 0.25}Mn{sub 0.75}As to be metallic. Calculated total magnetic moments and the robustness of half-metallicity of Ga{sub 0.75}Mn{sub 0.25}P, Ga{sub 0.75}Mn{sub 0.25}As and Ga{sub 0.5}Mn{sub 0.5}As with respect to the variation in lattice parameters are also discussed. The predicted theoretical evidence shows that some Mn-doped III–V semiconductors can be effectively used in spintronic devices.
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International Nuclear Information System (INIS)
Bergsma, J.
1970-06-01
Phonon dispersion relations in Mg 2 Sn and ZnS along the directions [001] , [110] and [111] are presented. Inelastic neutron scattering experiments were carried out by means of a triple-axis crystal spectrometer; for some optic branches the inverse beryllium-filter method was applied. A graphical method of focusing and calculations of inelastic structure factors were helpful in designing experiments. Group theory was employed for the block diagonalization of the dynamical matrices and the determination of eigenvectors. The dispersion relations are described by simple shell models allowing polarization of only one of the ions in each crystal. Zinc blende was found to be mainly covalent and magnesium stannide has an appreciable ionicity. (author)
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International Nuclear Information System (INIS)
Lee, Ling; Dai, Yue-Ru; Yang, Chu-Shou; Fan, Wen-Chung; Chou, Wu-Ching
2015-01-01
Highlights: • The localized emission in zinc-blende ZnCdSe is induced by excess selenium. • An optimized growth is demonstrated as the VI/II ratio approaches unity. • Size-independent lifetimes are observed in ZnTe/ZnCdSe quantum dots. • Localized electrons in the capping layer dominate size-independent lifetimes. - Abstract: This study discovered the origin of deep level emission in zinc-blende ZnCdSe thin films grown by molecular beam epitaxy, in which a localization behavior was noticed. Pronounced deep level emission observed in films grown under a VI/II ratio of 1.74 (Se-accumulated regime) could be suppressed by a lower VI/II ratio of 1.04 (intermediate regime) and 0.74 (metal-rich regime). Hence the localized states could be correlated to excess selenium accumulated at the growth surface. The localized states also influence the carrier relaxation process of self-assembled ZnTe quantum dots embedded in a ZnCdSe matrix. Once quantum dots surmount the wetting layer, localized electrons in the capping layer dominate the type-II transition and exhibit size-independent lifetimes
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Directory of Open Access Journals (Sweden)
H.Y. Wang
2012-03-01
Full Text Available The density-functional theory (DFT and density-functional perturbation theory (DFPT are employed to study the pressure dependence of elastic and dynamical properties of zinc-blende ZnS and ZnSe. The calculated elastic constants and phonon spectra from 0 GPa to 15 GPa are compared with the available experimental data. Generally, our calculated values are overestimated with experimental data, but agree well with recent other theoretical values. The discrepancies with experimental data are due to the use of local density approximation (LDA and effect of temperature. In this work, in order to compare with experimental data, we calculated and discussed the pressure derivatives of elastic constants, the pressure dependence of dynamical effect charge, and mode Grüneisen parameter at Γ.
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Heteroepitaxy of zinc-blende SiC nano-dots on Si substrate by organometallic ion beam
International Nuclear Information System (INIS)
Matsumoto, T.; Kiuchi, M.; Sugimoto, S.; Goto, S.
2006-01-01
The self-assembled SiC nano-dots were fabricated on Si(111) substrate at low-temperatures using the organometallic ion beam deposition technique. The single precursor of methylsilicenium ions (SiCH 3 + ) with the energy of 100 eV was deposited on Si(111) substrate at 500, 550 and 600 deg. C. The characteristics of the self-assembled SiC nano-dots were analyzed by reflection high-energy electron diffraction (RHEED), Raman spectroscopy and atomic force microscope (AFM). The RHEED patterns showed that the crystal structure of the SiC nano-dots formed on Si(111) substrate was zinc-blende SiC (3C-SiC) and it was heteroepitaxy. The self-assembled SiC nano-dots were like a dome in shape, and their sizes were the length of 200-300 nm and the height of 10-15 nm. Despite the low-temperature of 500 deg. C as SiC crystallization the heteroepitaxial SiC nano-dots were fabricated on Si(111) substrate using the organometallic ion beam
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Institute of Scientific and Technical Information of China (English)
PENG Si-Yan; YANG Liu-Sai; LV Ying-Ying; YU Le-Shu; HUANG Hai-Jin; WU Li-Dan
2017-01-01
Uniform and well-dispersed ZnS nanospheres have been successfully synthesized via a facile chemical route.The crystal structure,morphology,surface area and photocatalytic properties of the sample were characterized by powder X-ray diffraction (XRD),scanning electron microscopy (SEM),Brunauer-Emmett-Teller (BET) and ultraviolet-visible (UV-vis) spectrum.The results of characterizations indicate that the products are identified as mesoporous zinc-blende ZnS nanospheres with an average diameter of 200 nm,which are comprised of nanoparticles with the crystallite size of about 3.2 nm calculated by XRD.Very importantly,photocatalytic degradation of methylene blue (MB)shows that the as-prepared ZnS nanospheres exhibit excellent photocatalytic activity with nearly 100％ of MB decomposed after UV-light irradiation for 25 min.The excellent photocatalytic activity of ZnS nanospheres can be ascribed to the large specific surface area and hierarchical mesoporous structure.
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Antimicrobial effects of zinc oxide nanoparticles modified with silver
International Nuclear Information System (INIS)
Lopes, Rayssa Souza; Arantes, Tatiane Moraes
2016-01-01
Full text: With the emergence of resistant microbial organisms to multiple antibiotics, different shapes of silver nanoparticles are among the most promising antimicrobial agents that have been developed from nanotechnology. Besides the silver nanoparticles oxide nanoparticles such as zinc oxide (ZnO) is gaining prominence due to its bactericidal properties. [1-3]. Thus, this study aims to develop biomaterials from zinc oxide nanoparticles modified with silver with antimicrobial properties. The ZnO nanoparticles were synthesized by hydrothermal processing by alkaline hydrolysis zinc acetate. Colloidal dispersions of silver nanoparticles were synthesized by the Turkevich method using sodium citrate to reduce silver nitrate at high pH and at 90 °C in the presence of zinc oxide nanoparticles. Both nanoparticles were characterized by X-ray diffraction (XRD), FTIR and Raman spectroscopy and scanning electron microscopy (SEM). The XRD and Raman spectra showed crystalline ZnO colloidal nanoparticles were obtained in the hexagonal phase. XRD measure showed cubic silver diffraction peaks cubic phase confirmed the presence of the silver nanoparticles decorated zinc oxide nanoparticles. SEM images showed ZnO nanoparticles presented a nanorod shapes with length around 80 nm decorated with spherical silver nanoparticles about 20 nm in diameter The results showed that crystalline zinc oxide colloidal nanoparticles with rod-like morphology and uniform decorated with silver spherical nanoparticles size were obtained by hydrothermal synthesis. Results of antibacterial tests indicate that the ZnO/Ag nanoparticles have antibacterial properties against both Staphylococcus aureus and Escherichia coli. The results demonstrated that the ZnO/Ag nanoparticles have potential use as biomaterials in medical/odontological applications. (author)
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Antimicrobial effects of zinc oxide nanoparticles modified with silver
Energy Technology Data Exchange (ETDEWEB)
Lopes, Rayssa Souza; Arantes, Tatiane Moraes, E-mail: rayssasouza.net@gmail.com [Universidade Federal de Goias (UFG), Goiania (Brazil)
2016-07-01
Full text: With the emergence of resistant microbial organisms to multiple antibiotics, different shapes of silver nanoparticles are among the most promising antimicrobial agents that have been developed from nanotechnology. Besides the silver nanoparticles oxide nanoparticles such as zinc oxide (ZnO) is gaining prominence due to its bactericidal properties. [1-3]. Thus, this study aims to develop biomaterials from zinc oxide nanoparticles modified with silver with antimicrobial properties. The ZnO nanoparticles were synthesized by hydrothermal processing by alkaline hydrolysis zinc acetate. Colloidal dispersions of silver nanoparticles were synthesized by the Turkevich method using sodium citrate to reduce silver nitrate at high pH and at 90 °C in the presence of zinc oxide nanoparticles. Both nanoparticles were characterized by X-ray diffraction (XRD), FTIR and Raman spectroscopy and scanning electron microscopy (SEM). The XRD and Raman spectra showed crystalline ZnO colloidal nanoparticles were obtained in the hexagonal phase. XRD measure showed cubic silver diffraction peaks cubic phase confirmed the presence of the silver nanoparticles decorated zinc oxide nanoparticles. SEM images showed ZnO nanoparticles presented a nanorod shapes with length around 80 nm decorated with spherical silver nanoparticles about 20 nm in diameter The results showed that crystalline zinc oxide colloidal nanoparticles with rod-like morphology and uniform decorated with silver spherical nanoparticles size were obtained by hydrothermal synthesis. Results of antibacterial tests indicate that the ZnO/Ag nanoparticles have antibacterial properties against both Staphylococcus aureus and Escherichia coli. The results demonstrated that the ZnO/Ag nanoparticles have potential use as biomaterials in medical/odontological applications. (author)
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Preparation of boron-nitrogen films by sputtering
International Nuclear Information System (INIS)
Klose, S.; Winde, B.
1980-01-01
Hard boron-nitrogen films adherent to various substrates can be prepared by sputtering. IR investigations suggest the existence of cubic boron nitride in certain layers. Transmission electron microscope studies have shown a quasi-amorphous structure irregularly incorporating crystallites of zinc blende structure of some nm in diameter
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International Nuclear Information System (INIS)
Xia Congxin; Zeng Zaiping; Liu, Z.S.; Wei, S.Y.
2010-01-01
Based on the effective-mass approximation, the effects of the electric field and hydrostatic pressure on exciton states in a cylindrical zinc-blende (ZB) GaN/AlGaN quantum dot (QD) are investigated variationally. Numerical results show that the electric field leads to a remarkable reduction of the ground-state exciton binding energy and interband transition energy in the case of any hydrostatic pressures. However, the hydrostatic pressure increases the exciton binding energy and interband transition energy in the case of any electric fields. In particular, the electric field has a remarkable influence on the exciton binding energy in the QD with large dot size and small hydrostatic pressure; moreover, the hydrostatic pressure obviously affects the exciton binding energy in the QD with small dot size and weak electric field.
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Ab initio study of the stability and electronic properties of wurtzite and zinc-blende BeS nanowires
Energy Technology Data Exchange (ETDEWEB)
Faraji, Somayeh [Simulation Laboratory, Department of Physics, Faculty of Science, Shahrekord University, Shahrekord (Iran, Islamic Republic of); Mokhtari, Ali, E-mail: mokhtari@sci.sku.ac.i [Simulation Laboratory, Department of Physics, Faculty of Science, Shahrekord University, Shahrekord (Iran, Islamic Republic of); Nanotechnology Research Center, Shahrekord University, Shahrekord (Iran, Islamic Republic of)
2010-07-19
In this work we study the structural stability and electronic properties of the Beryllium sulfide nanowires (NWs) in zinc-blende (ZB) and wurtzite (WZ) phases (with triangle and hexagonal cross sections), using first principle calculations within the plane-wave pseudopotential method. A phenomenological model is used to explain the role of dangling bonds in the stability of the NWs. In contrast to the bulk phase, the ZB-NWs with diameters less than 133.3 A are found to be less favorable over the WZ-NWs, in which the surface dangling bonds (DBs) on the NW facets play an important role to stabilize the NWs. Furthermore, both ZB- and WZ-NWs are predicted to be semiconductor and the values of the band gaps are dependent on the surface DBs as well as the size and shape of the NWs. Finally, we obtain atom projected density of states (PDOSs) by calculating the localized density of states on the surface atoms, as well as on the core and edge atoms.
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Ab initio study of the stability and electronic properties of wurtzite and zinc-blende BeS nanowires
International Nuclear Information System (INIS)
Faraji, Somayeh; Mokhtari, Ali
2010-01-01
In this work we study the structural stability and electronic properties of the Beryllium sulfide nanowires (NWs) in zinc-blende (ZB) and wurtzite (WZ) phases (with triangle and hexagonal cross sections), using first principle calculations within the plane-wave pseudopotential method. A phenomenological model is used to explain the role of dangling bonds in the stability of the NWs. In contrast to the bulk phase, the ZB-NWs with diameters less than 133.3 A are found to be less favorable over the WZ-NWs, in which the surface dangling bonds (DBs) on the NW facets play an important role to stabilize the NWs. Furthermore, both ZB- and WZ-NWs are predicted to be semiconductor and the values of the band gaps are dependent on the surface DBs as well as the size and shape of the NWs. Finally, we obtain atom projected density of states (PDOSs) by calculating the localized density of states on the surface atoms, as well as on the core and edge atoms.
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Electronic states of a hydrogenic impurity in a zinc-blende GaN/AlGaN quantum well
International Nuclear Information System (INIS)
Pattammal, M.; Peter, A. John
2010-01-01
Binding energies of ground and a few low lying excited states of a hydrogenic donor confined in a zinc-blende GaN/AlGaN quantum well are investigated. They are computed within the framework of single band effective mass approximation, by means of a variational approach. The donor states are investigated with the various impurity positions as a function of well width. The calculations have been carried out with the inclusion of conduction band non-parabolicity through the energy dependent effective mass. The variational solutions have been improved by using a two-parametric trial wavefunction. The results seem better and good agreement with the other investigators. To support our results, we observe that the values of variational parameters are consistent when two parameter wave function is used. We find that the inclusion of non-parabolic effects leads to more binding for all the values of well width and is significant for narrow wells. The results are compared with the existing available literature.
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Electronic states of a hydrogenic impurity in a zinc-blende GaN/AlGaN quantum well
Energy Technology Data Exchange (ETDEWEB)
Pattammal, M. [Dept.of Physics, Yadava College Coeducational Institute, Madurai 625 014 (India); Peter, A. John, E-mail: a.john.peter@gmail.com [Dept.of Physics, Govt. Arts and Science College, Melur 625 106 (India)
2010-09-01
Binding energies of ground and a few low lying excited states of a hydrogenic donor confined in a zinc-blende GaN/AlGaN quantum well are investigated. They are computed within the framework of single band effective mass approximation, by means of a variational approach. The donor states are investigated with the various impurity positions as a function of well width. The calculations have been carried out with the inclusion of conduction band non-parabolicity through the energy dependent effective mass. The variational solutions have been improved by using a two-parametric trial wavefunction. The results seem better and good agreement with the other investigators. To support our results, we observe that the values of variational parameters are consistent when two parameter wave function is used. We find that the inclusion of non-parabolic effects leads to more binding for all the values of well width and is significant for narrow wells. The results are compared with the existing available literature.
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Dynamical properties and their strain-dependence of ZnSe(ZnSe:N: Zinc-blende and wurtzite
Directory of Open Access Journals (Sweden)
Dandan Wang
2014-06-01
Full Text Available The lattice dynamical properties of ZnSe and ZnSe with substitutional N incorporation(ZnSe:N are investigated in both the zinc-blend(ZB and wurtzite(WZ structures using first-principles calculations. The optical phonon modes of ZB-ZnSe at the Γ-point locate at 250 cm−1 for LO and 213 cm−1 for TO. The characteristic E2 phonon modes at about 50 cm−1 and the E1 and another E2 phonon modes around 200 cm−1 of WZ-ZnSe are suggested to be the fingerprint for distinguishing the two polytypes of ZnSe. For substitutional N incorporated ZnSe, the N incorporation introduces three new high energy modes above 500 cm−1, and the splitting of them is much larger in the WZ phase than that in ZB phase. The strain dependence of phonon frequency which could be useful for corresponding spectroscopic strain characterization are also studied. The simple linear dependence is determined for ZB-ZnSe, while the situation for WZ-ZnSe looks more complicated.
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Twins and strain relaxation in zinc-blende GaAs nanowires grown on silicon
Energy Technology Data Exchange (ETDEWEB)
Piñero, J.C., E-mail: josecarlos.pinero@uca.es [Dpto. Ciencias de los Materiales, Universidad de Cádiz, 11510, Puerto Real, Cádiz (Spain); Araújo, D.; Pastore, C.E.; Gutierrez, M. [Dpto. Ciencias de los Materiales, Universidad de Cádiz, 11510, Puerto Real, Cádiz (Spain); Frigeri, C. [Istituto CNR-IMEM Parco Area delle Scienze 37/A, Fontanini, 43010, Parma (Italy); Benali, A.; Lelièvre, J.F.; Gendry, M. [INL-Institut des Nanotechnologies de Lyon, UMR 5270 Ecole Centrale de Lyon 36, Avenue Guy de Collongue, 69134, Ecully Cedex (France)
2017-02-15
Highlights: • A TEM-HREM study of GaAs nanowires, growth over Si, is presented. • Misfit dislocations are detected in the Si/GaAs magma interface. • The study demonstrates strain relaxation through twin formation in some nanowires. - Abstract: To integrate materials with large lattice mismatch as GaAs on silicon (Si) substrate, one possible approach, to improve the GaAs crystalline quality, is to use nanowires (NWs) technology. In the present contribution, NWs are grown on <111> oriented Si substrates by molecular beam epitaxy (MBE) using vapor-liquid-solid (VLS) method. Transmission electron microscopy (TEM) analyses show that NWs are mainly grown alternating wurtzite and zinc blend (ZB) phases, and only few are purely ZB. On the latter, High Resolution Electron Microscopy (HREM) evidences the presence of twins near the surface of the NW showing limited concordance with the calculations of Yuan (2013) [1], where {111} twin planes in a <111>-oriented GaAs NW attain attractive interactions mediated by surface strain. In addition, such twins allow slight strain relaxation and are probably induced by the local huge elastic strain observed by HREM in the lattice between the twin and the surface. The latter is attributed to some slight bending of the NW as shown by the inversion of the strain from one side to the other side of the NW.
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Energy Technology Data Exchange (ETDEWEB)
Cattaruzza, E., E-mail: cattaruz@unive.it [Department of Molecular Sciences and Nanosystems, Ca’ Foscari University of Venice, Via Torino 155/B, 30172 Mestre-VE (Italy); Battaglin, G.; Riello, P. [Department of Molecular Sciences and Nanosystems, Ca’ Foscari University of Venice, Via Torino 155/B, 30172 Mestre-VE (Italy); Cristofori, D. [Department of Molecular Sciences and Nanosystems, Ca’ Foscari University of Venice and Centre for Electron Microscopy “Giovanni Stevanato”, Via Torino 155/B, 30172 Mestre-VE (Italy); Tamisari, M. [Department of Physics and Earth Sciences, University of Ferrara, Via Saragat 1, 44121 Ferrara (Italy)
2014-11-30
Highlights: • RuN thin films in the zinc-blende structure have been synthesized by rf-magnetron sputtering. • Contribute is given to the understanding of phase-formation mechanisms in systems that under ambient conditions present positive enthalpies of formation. • Contribute is given to the understanding of phenomena occurring during reactive sputtering processes. • Nanopillar structure: suitable for application requiring a high effective area, like sensing, catalysis, and electrode material for energy-storage devices. - Abstract: 4d- and 5d-transition metal nitrides are of interest both because of their importance for the understanding of mechanisms of phase formation in systems that under ambient conditions present positive enthalpies of formation and because of their appealing structural and electronic properties. In this study, we report the synthesis of thin films of ruthenium mononitride (RuN) in the zinc-blende structure by radio-frequency-magnetron sputtering. Films present a characteristic structure of packed columns ending with tetrahedral tips. The effect of changing the synthesis parameters was investigated in detail. It was found that RuN can be formed if the nitrogen partial pressure exceeds a minimum value and that the addition of argon has the major effect of increasing the deposition rate because of its higher sputter ability. Temperature plays an important role: if it is too high, decomposition/desorption effects overcome those leading to the formation of the compound. Phenomena resulting in the formation of RuN occur at the surface of the growing films and are related to the interactions of ruthenium with energetic nitrogen ions, or atoms, which can penetrate the first atomic layers by low energy implantation. Because of its properties and structure, this material is a promising candidate for applications like sensing, catalysis, and electrode material for energy-storage devices.
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First principle study of cubic ScGaN ternaries
International Nuclear Information System (INIS)
Adli, W.; Mecheref, R.; Sekkal, N.; Tair, F.; Amrani, B.
2008-08-01
The electronic properties of the Sc x Ga1- x N ternary alloy are investigated. The transition from rocksalt (B1) to zinc blende (B3) structure is found to occur rapidly after incorporating just a small fraction (less than 1%) of Ga. In the present paper, the first principles method the full potential linear muffin-tin orbitals method (FPLMTO) in its atomic sphere approximation (ASA) coupled to the technique of the empty spheres is employed. Our results concerning the electronic properties are different from those reported in literature. (author)
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International Nuclear Information System (INIS)
Galanakis, I.; Pouliasis, S.G.
2009-01-01
We present an extended study of single impurity atoms and atomic swaps in half-metallic CrAs, CrSb and CrSe zinc-blende compounds. Although the perfect alloys present a rather large gap in the minority-spin band, all defects under study, with the exception of void impurities at Cr and sp sites and Cr impurities at sp sites (as long as no swap occurs), induce new states within the gap. The Fermi level can be pinned within these new minority states depending on the lattice constant used for the calculations and the electronegativity of the sp atoms. Although these impurity states are localized in space around the impurity atoms and very fast we regain the bulk behavior, their interaction can lead to wide bands within the gap and thus loss of the half-metallic character
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Berber Yamak, Hale
2016-01-01
In this study, low density polyethylene, LDPE was melt blended with starch using twin screw extruder to form biodegradable polymer blends. The LDPE/starch blend films used in food packing were obtained by hot pressing of the granules produced by extrusion process. The starch content was varied from 0 to 40 wt% of LDPE. To provide fine starch dispersion, glycerol and zinc stearate were used as plasticizer and compatibilizer, respectively. The effect of starch content on the properties of LDPE ...
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Energy Technology Data Exchange (ETDEWEB)
1981-03-01
Progress in the development of nickel-zinc batteries for electric vehicles is reported. Information is presented on nickel electrode preparation and testing; zinc electrode preparation with additives and test results; separator development and the evaluation of polymer-blend separator films; sealed Ni-Zn cells; and the optimization of electric vehicle-type Ni-Zn cells. (LCL)
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G2 cubic transition between two circles with shape control
Habib, Zulfiqar; Sakai, Manabu
2009-01-01
This paper describes a method for joining two circles with an S-shaped or with a broken back C-shaped transition curve, composed of at most two spiral segments. In highway and railway route design or car-like robot path planning, it is often desirable to have such a transition. It is shown that a single cubic curve can be used for blending or for a transition curve preserving G2 continuity with local shape control parameter and more flexible constraints. Provision of the shape parameter and flexibility provide freedom to modify the shape in a stable manner which is an advantage over previous work by Meek, Walton, Sakai and Habib.
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Directory of Open Access Journals (Sweden)
Krzysztof Marycz
2016-04-01
Full Text Available Polymeric biomaterials based on polyurethane and polylactide blends are promising candidates for regenerative medicine applications as biocompatible, bioresorbable carriers. In current research we showed that 80/20 polyurethane/polylactide blends (PU/PLDL with confirmed biological properties in vitro may be further improved by the addition of ZnO nanoparticles for the delivery of bioactive zinc oxide for cells. The PU/PLDL blends were doped with different concentrations of ZnO (0.001%, 0.01%, 0.05% and undertaken for in vitro biological evaluation using human adipose stromal stem cells (ASCs and olfactory ensheathing cells (OECs. The addition of 0.001% of ZnO to the biomaterials positively influenced the morphology, proliferation, and phenotype of cells cultured on the scaffolds. Moreover, the analysis of oxidative stress markers revealed that 0.001% of ZnO added to the material decreased the stress level in both cell lines. In addition, the levels of neural-specific genes were upregulated in OECs when cultured on sample 0.001 ZnO, while the apoptosis-related genes were downregulated in OECs and ASCs in the same group. Therefore, we showed that PU/PLDL blends doped with 0.001% of ZnO exert beneficial influence on ASCs and OECs in vitro and they may be considered for future applications in the field of regenerative medicine.
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Energy Technology Data Exchange (ETDEWEB)
Chapi, Sharanappa; Niranjana, M.; Devendrappa, H., E-mail: dehu2010@gmail.com [Department of Physics, Mangalore University, Mangalagangothri - 574 199 (India)
2016-05-23
Solid Polymer blend electrolytes based on Polyethylene oxide (PEO) and poly vinyl pyrrolidone (PVP) complexed with zinc oxide nanoparticles (ZnO NPs; Synthesized by Co-precipitation method) thin films have prepared at a different weight percent using the spin-coating method. The complexation of the NPs with the polymer blend was confirmed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR). The variation in film morphology was examined by polarized optical micrographs (POMs). The thermal behavior of blends was investigated under non-isothermal conditions by differential thermal analyses (DTA). A single glass transition temperature for each blend was observed, which supports the existence of compatibility of such system. The obtained results represent that the ternary based thin films are prominent materials for battery and optoelectronic device applications.
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Cubical local partial orders on cubically subdivided spaces - existence and construction
DEFF Research Database (Denmark)
Fajstrup, Lisbeth
The geometric models of Higher Dimensional Automata and Dijkstra's PV-model are cubically subdivided topological spaces with a local partial order. If a cubicalization of a topological space is free of immersed cubic Möbius bands, then there are consistent choices of direction in all cubes, such ...... that the underlying geometry of an HDA may be quite complicated....
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Cubical local partial orders on cubically subdivided spaces - Existence and construction
DEFF Research Database (Denmark)
Fajstrup, Lisbeth
2006-01-01
The geometric models of higher dimensional automata (HDA) and Dijkstra's PV-model are cubically subdivided topological spaces with a local partial order. If a cubicalization of a topological space is free of immersed cubic Möbius bands, then there are consistent choices of direction in all cubes...... that the underlying geometry of an HDA may be quite complicated....
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Atomistic aspects of ductile responses of cubic silicon carbide during nanometric cutting.
Goel, Saurav; Luo, Xichun; Reuben, Robert L; Rashid, Waleed Bin
2011-11-11
Cubic silicon carbide (SiC) is an extremely hard and brittle material having unique blend of material properties which makes it suitable candidate for microelectromechanical systems and nanoelectromechanical systems applications. Although, SiC can be machined in ductile regime at nanoscale through single-point diamond turning process, the root cause of the ductile response of SiC has not been understood yet which impedes significant exploitation of this ceramic material. In this paper, molecular dynamics simulation has been carried out to investigate the atomistic aspects of ductile response of SiC during nanometric cutting process. Simulation results show that cubic SiC undergoes sp3-sp2 order-disorder transition resulting in the formation of SiC-graphene-like substance with a growth rate dependent on the cutting conditions. The disorder transition of SiC causes the ductile response during its nanometric cutting operations. It was further found out that the continuous abrasive action between the diamond tool and SiC causes simultaneous sp3-sp2 order-disorder transition of diamond tool which results in graphitization of diamond and consequent tool wear.
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Effect of ZnO nano in the blend PET / PC ( 80/20) subjected to UV radiation
International Nuclear Information System (INIS)
Pires, Homero M.; Mendes, Luis C.; Albitres, Gerson A.V.; Cestari, Sibele P.; Mattos, Gabriela C.
2015-01-01
The aim of this research was to reuse recycled poly(ethylene terephthalate) (PET) in blend with polycarbonate (PC) in order to avoid UV degradation in outdoor application. Nanocomposite based on blend of recycled (PET) and polycarbonate (PC) in the ratio of 80/20 with nano zinc oxide (ZnO) at different concentrations was prepared. The blend was subjected to ultraviolet (UV) radiation for accelerated aging chamber, we evaluated the effect of the presence nZnO filler as a barrier to UV rays. Dynamic-mechanical analysis (DMA) and nuclear magnetic resonance in the solid state (NMR). It is the degradation retardant effect at concentrations starting from 3% nZnO. (author)
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Determination of main components in lanthanum titanates blend
International Nuclear Information System (INIS)
Sizonenko, T.N.; Timchenko, A.K.
1981-01-01
Conditions for complexonometric determination of lanthanum in the presence of titanium using the disguising of the latter are studied. A method is suggested for lanthanum and titanium determination in a blend of lanthanum titanate which is used to grow monocrystals. Sulfosalicylic acid is chosen as a disguising agent. La has been determined by complexonometric titration using EDTA with xylenol orange in urotropin. The total contents of La and Ti have been determined by titration of EDTA excess with standard solution of zinc sulfate. Ti content has been calculated from the difference between the first two determinations. Reproducibility of Ti and La determination in the blend (n=21) is characterized by the following: at 19.73% La and 57.21% Ti there are (19.72+-0.16)% La and (57.10+-0.22)% Ti, Sr equals 0.0071 and 0.0034, respectively
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Energy Technology Data Exchange (ETDEWEB)
Siddiqua, Poppy; O' Leary, Stephen K., E-mail: stephen.oleary@ubc.ca [School of Engineering, The University of British Columbia, 3333 University Way, Kelowna, British Columbia V1V 1V7 (Canada)
2016-09-07
Within the framework of a semi-classical three-valley Monte Carlo simulation approach, we analyze the steady-state and transient electron transport that occurs within bulk zinc-blende gallium nitride. In particular, we examine how the steady-state and transient electron transport that occurs within this material changes in response to variations in the crystal temperature, the doping concentration, and the non-parabolicity coefficient associated with the lowest energy conduction band valley. These results are then contrasted with those corresponding to a number of other compound semiconductors of interest.
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Remediation of arsenic and lead with nanocrystalline zinc sulfide.
Piquette, Alan; Cannon, Cody; Apblett, Allen W
2012-07-27
Nanocrystalline (1.7 ± 0.3 nm) zinc sulfide with a specific surface area up to 360 m(2) g(-1) was prepared from the thermal decomposition of a single-source precursor, zinc ethylxanthate. Zinc ethylxanthate decomposes to cubic zinc sulfide upon exposure to temperatures greater than or equal to 125 °C. The resulting zinc sulfide was tested as a water impurity extractant. The target impurities used in this study were As(5+), As(3+), and Pb(2+). The reaction of the nanocrystalline ZnS with Pb(2+) proceeds as a replacement reaction where solid PbS is formed and Zn(2+) is released into the aqueous system. Removal of lead to a level of less than two parts per billion is achievable. The results of a detailed kinetics experiment between the ZnS and Pb(2+) are included in this study. Unlike the instance of lead, both As(5+) and As(3+) adsorb on the surface of the ZnS extractant as opposed to an ion-exchange process. An uptake capacity of > 25 mg g(-1) for the removal of As(5+) is possible. The uptake of As(3+) appears to proceed by a slower process than that of the As(5+) with a capacity of nearly 20 mg g(-1). The nanocrystalline zinc sulfide was extremely successful for the removal of arsenic and lead from simulated oil sand tailing pond water.
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International Nuclear Information System (INIS)
Jiang, Nanke; Georgiev, Daniel G.; Wen, Ting; Jayatissa, Ahalapitiya H.
2012-01-01
Zinc nitride films were deposited on glass or silicon substrates by reactive magnetron radio frequency sputtering of zinc in either N 2 –Ar or N 2 –Ar–O 2 ambient. The effects of varying the nitrogen contents and the substrate temperature were investigated. X-ray diffraction data showed that the as-deposited films contain the zinc nitride cubic crystalline phase with a preferred orientation, and Raman scattering measurements revealed Zn-N related modes. According to energy-dispersive X-ray spectroscopy analysis, the as-deposited films were nitrogen-rich and contained only a small fraction of oxygen. Hall-effect measurements showed that p-type zinc nitride with carrier concentration of ∼ 10 19 cm −3 , mobility of ∼ 10 1 cm 2 /Vs, resistivity of ∼ 10 −2 Ω ∗ cm, was obtained. The photon energy dependence of optical transmittance suggested that the material has an indirect bandgap.
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Extinction in an extended-face crystal of zinc selenide
International Nuclear Information System (INIS)
Stevenson, A.W.; Barnea, Z.
1982-01-01
X-ray intensity measurements from an extended-face single crystal of cubic zinc selenide obtained by McIntyre, Moss and Barnea (1980) have been re-analysed with a view to explaining the unresolved discrepancies between theory and experiment present in the original analysis of the most severely extinguished reflections. The results are shown to complement the recent findings of a wavelength dependent study using the same crystal specimen and foreshadow the need to allow for the presence of the Borrmann effect
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Formulation of Synthesized Zinc Oxide Nanopowder into Hybrid Beads for Dye Separation
Directory of Open Access Journals (Sweden)
H. Shokry Hassan
2014-01-01
Full Text Available The sol-gel prepared zinc oxide nanopowder was immobilized onto alginate-polyvinyl alcohol polymer blend to fabricate novel biocomposite beads. Various physicochemical characterization techniques have been utilized to identify the crystalline, morphological, and chemical structures of both the fabricated zinc oxide hybrid beads and their corresponding zinc oxide nanopowder. The thermal stability investigations demonstrate that ZnO nanopowder stability dramatically decreased with its immobilization into the polymeric alginate and PVA matrix. The formulated beads had very strong mechanical strength and they are difficult to be broken up to 1500 rpm. Moreover, these hybrid beads are chemically stable at the acidic media (pH < 7 especially within the pH range of 2–7. Finally, the applicability of the formulated ZnO hybrid beads for C.I. basic blue 41 (BB41 decolorization from aqueous solution was examined.
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CSIR Research Space (South Africa)
Motaung, DE
2013-06-01
Full Text Available The structural growth and optical and photovoltaic properties of the organic–inorganic hybrid structures of zinc oxide (ZnO)-nanorods/poly-3-hexylthiophene (P3HT) and two variations of organic polymer blends of ZnO/P3HT:C(sub60) fullerene and ZnO/P3...
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Cubic metaplectic forms and theta functions
Proskurin, Nikolai
1998-01-01
The book is an introduction to the theory of cubic metaplectic forms on the 3-dimensional hyperbolic space and the author's research on cubic metaplectic forms on special linear and symplectic groups of rank 2. The topics include: Kubota and Bass-Milnor-Serre homomorphisms, cubic metaplectic Eisenstein series, cubic theta functions, Whittaker functions. A special method is developed and applied to find Fourier coefficients of the Eisenstein series and cubic theta functions. The book is intended for readers, with beginning graduate-level background, interested in further research in the theory of metaplectic forms and in possible applications.
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Studies of PVC/ENR blends: blend compositions
International Nuclear Information System (INIS)
Chantara Thevy Ratnam; Khairul Zaman Mohd Dahlan; Nasir, M.; Baharin, A.
2002-01-01
Blends of poly(vinyl chloride/epoxidized natural rubber (PVC/ENR) were prepared by using Bra bender Plasticorder at compositions ranging from 0-100% PVC. They were blended at 150 degree C mixing temperature, 50 rpm rotor speed and 10 minutes mixing time. The blends were characterized for tensile strength , elongation at break, glass transition temperatures and Fourier transform infra red spectroscopy (FTIR). Results revealed that as the PVC content increases the blend behaviour changes from elastomeric to glassy. However the blends found to be compatible at all compositions. (Author)
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Cubic colloids : Synthesis, functionalization and applications
Castillo, S.I.R.
2015-01-01
This thesis is a study on cubic colloids: micron-sized cubic particles with rounded corners (cubic superballs). Owing to their shape, particle packing for cubes is more efficient than for spheres and results in fascinating phase and packing behavior. For our cubes, the particle volume fraction when
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Mahajan, Dhiraj S.; Deshpande, Tushar; Bari, Mahendra L.; Patil, Ujwal D.; Narkhede, Jitendra S.
2018-04-01
In the present study, we prepared zinc borates using aqueous phase synthesis under moderate pressures (MP) (ethanol as a co-solvent in the presence of a quaternary ammonium surfactant-Cetyltrimethylammonium bromide (CTAB). 3D morphologies of self-assembled zinc borate (Zn(H2O)B2O4 · 0.12 H2O, Zn3B6O12 · 3.5H2O, ZnB2O4) resembling flower-like structures were obtained by varying temperature under moderate pressure conditions. Synthesized zinc borates’ florets were morphologically characterized by Field Emission Scanning Electron Microscopy. The x-ray diffractions of borate species reveal rhombohydra, monoclinic and cubic phases of zinc borate crystals as a function of process temperature. Additionally, thermal analysis confirms excellent dehydration/degradation behavior for the zinc borate crystals synthesized at moderate pressures and elevated temperatures and could be utilized as potential flame retardant fillers in the polymer matrices.
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Zinc fingers, zinc clusters, and zinc twists in DNA-binding protein domains
International Nuclear Information System (INIS)
Vallee, B.L.; Auld, D.S.; Coleman, J.E.
1991-01-01
The authors recognize three distinct motifs of DNA-binding zinc proteins: (i) zinc fingers, (ii) zinc clusters, and (iii) zinc twists. Until very recently, x-ray crystallographic or NMR three-dimensional structure analyses of DNA-binding zinc proteins have not been available to serve as standards of reference for the zinc binding sites of these families of proteins. Those of the DNA-binding domains of the fungal transcription factor GAL4 and the rat glucocorticoid receptor are the first to have been determined. Both proteins contain two zinc binding sites, and in both, cysteine residues are the sole zinc ligands. In GAL4, two zinc atoms are bound to six cysteine residues which form a zinc cluster akin to that of metallothionein; the distance between the two zinc atoms of GAL4 is ∼3.5 angstrom. In the glucocorticoid receptor, each zinc atom is bound to four cysteine residues; the interatomic zinc-zinc distance is ∼13 angstrom, and in this instance, a zinc twist is represented by a helical DNA recognition site located between the two zinc atoms. Zinc clusters and zinc twists are here recognized as two distinctive motifs in DNA-binding proteins containing multiple zinc atoms. For native zinc fingers, structural data do not exist as yet; consequently, the interatomic distances between zinc atoms are not known. As further structural data become available, the structural and functional significance of these different motifs in their binding to DNA and other proteins participating in the transmission of the genetic message will become apparent
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Energy Technology Data Exchange (ETDEWEB)
Zhang, Yong [School of Mathematics, Physics and Energy Engineering, Hunan Institute of Technology, Hengyang 421002 (China); Xie, Zhong-Xiang, E-mail: xiezxhu@163.com [School of Mathematics, Physics and Energy Engineering, Hunan Institute of Technology, Hengyang 421002 (China); Yu, Xia; Wang, Hai-Bin; Deng, Yuan-Xiang [School of Mathematics, Physics and Energy Engineering, Hunan Institute of Technology, Hengyang 421002 (China); Ning, Feng, E-mail: fning@gxtc.edu.cn [College of Physics and Electronic Engineering, Guangxi Teachers Education University, Nanning 530001 (China)
2016-08-06
Using first-principle calculations with density functional theory, we investigated the modification of electronic properties in zinc-blende (ZB) and wurtzite (WZ) InSb nanowires (NWs) grown along the [111] and [0001] directions for different size, different surface coverage and different mechanical strain. The results show that before the surface passivation, ZBNWs and WZNWs exhibit the metallic character and the semiconductor character, respectively. WZNWs show a crossover from a direct to an indirect as diameter decreases. After the surface passivation, both ZBNWs and WZNWs are found to be direct-gap character. The electronic band structure shows a significant response to changes in surface passivation with pseudo hydrogen and halogen. The band structure with mechanical strain is strongly dependent on the crystal orientation and the NW diameter. In ZBNWs, compressive strain induces the indirect band gap character, whereas tensile strain can not form it. WZNWs have various strain dependence in that both compressive and tensile strain make InSb show a direct band gap character. A brief analysis of these results is given. - Highlights: • InSb nanowires with different surfaces can show the different band structures. • Band gap magnitude of InSb nanowires depends on the suppression of surface states. • Different types of mechanical strains show the different effect on the band structure of the InSb nanowires.
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Blend or not to blend: a study investigating faculty members perceptions of blended teaching
Directory of Open Access Journals (Sweden)
Mehmet A Ocak
2010-12-01
Full Text Available This study examined faculty members’ perceptions of blended teaching from several perspectives. A total of 73 faculty members in Turkish Higher Education context participated in the study by completing an online survey that combined quantitative and qualitative approaches. Based on a data analysis, the faculty members’ perceptions were sorted into six categories: (a satisfaction with blended teaching, (b perceived impact on the role of the faculty, (c perceived impact on student learning, (d perceived impact on student motivation, (e advantages of blended teaching, and (f disadvantages of blended teaching. Findings indicated that faculty members were likely to agree that blended teaching provides a high degree of satisfaction and that it requires more time and commitment from the faculty. The faculty members perceived that blended teaching improves student learning and, to some extent, improves motivation. The faculty members also emphasized the importance of institutional support and the use of technology to mitigate student problems. This study presents these faculty members’ perceptions, which are helpful for those planning to implement a blended teaching approach, and makes suggestions for trouble-shooting and taking advantage of the opportunities in a blended environment successfully.
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International Nuclear Information System (INIS)
Mizuguchi, M.; Manago, T.; Akinaga, H.; Yamada, T.; Yagi-Watanabe, K.; Yuri, M.; Chen, C.T.; Shirai, M.
2004-01-01
Full text: Half-metallic ferromagnets such as CrO 2 and Heusler alloys have attracted a great deal of attention due to its application to spin-dependent device. We have predicted by first principle calculations that zinc-blende (zb) type CrAs, which normally exists in a MnP type, shows a half-metallic band structure, and succeeded in fabrication of this film. However, the epitaxial growth with maintaining a zb structure was limited up to around the nominal thickness of 3 nm. In this contribution, ultraviolet magnetic circular dichroism (MCD) and x-ray absorption spectroscopy (XAS) of CrAs multilayers are reported. These multilayers include zb-CrAs layers and low-temperature GaAs layers stacked alternately, and total thicknesses of zb- CrAs are thicker than 3 nm. Incident beam with the photon energy from 4 to 8 eV were used, and samples were attached on a magnet with the magnetic field of 1.0 T for the MCD measurements. Strong signal with the peak top at 6.5 eV is observed in the MCD spectrum. It can be seen that the experimental spectrum has a good agreement with the theoretical one, which indicates the formation of a superstructure as designed. It was also clarified by the XAS measurement using incident beam from 560 to 600 eV that peak positions of these multilayers shift systematically according to the thickness of each layer. The CrAs/GaAs multilayer is also expected to possess a half-metallic property by the theoretical calculation, therefore, the present result shows the multilayer will be the promising candidate as the spin electronics material
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Evaluation of iron, zinc, copper, manganese and selenium in oral hospital diets.
Moreira, Daniele Caroline Faria; Sá, Júlia Sommerlatte Manzoli de; Cerqueira, Isabel B.; Oliveira, Ana P. F. de; Morgano, Marcelo Antonio; Quintaes, Késia Diego
2013-01-01
Background & aims: Many trace elements are nutrients essential to humans, acting in the metabolism as constituents or as enzymatic co-factors. The iron, zinc, copper, manganese and selenium contents of hospital diets (regular, blend and soft) and of oral food complement (OFC) were determined, evaluating the adequacy of each element in relation to the nutritional recommendations (DRIs) and the percent contribution alone and with OFC. Methods: Duplicate samples were taken of six daily meals ...
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Zinc-aluminates for an in situ sulfur reduction in cracked gasoline
Energy Technology Data Exchange (ETDEWEB)
Quintana-Solorzano, R.; Valente, J.S.; Hernandez-Beltran, F.J.; Castillo-Araiza, C.O. [Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas Norte 152 C.P., 07730 Mexico, D.F. (Mexico)
2008-05-30
Using additives remains as an attractive alternative for an in situ sulfur reduction in cracked gasoline since it is a practical, flexible and economical option. Zinc-aluminates prepared by the sol-gel method are used as additives for reducing sulfur in gasoline from the cracking of a high-sulfur feed in a fixed-bed bench reactor. Products distribution and feed conversion are not dramatically altered after incorporating the additive to the base catalyst with some effect on gasoline and its octane number and coke. A decrease in the gasoline sulfur content of up to 35 wt% including benzothiophene, and up to 50% excluding benzothiophene, is observed when blending the zinc-aluminates to the base catalyst, which is caused by lowering the C{sub 1} to C{sub 4} alkyl-thiophenes content. The zinc content of the zinc-aluminates has a positive effect on the gasoline sulfur reduction. It is suggested that together with the direct cracking of adsorbed thiophenic species on the additive, a further gasoline sulfur decrease is possible through cracking of saturated thiophenic species formed by hydrogenation of adsorbed thiophenic species with hydrogen produced in situ in the additive. The obtained results also demonstrate that solids with higher Lewis acidity are not unfailingly the most effective for gasoline sulfur reduction. (author)
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Dauguet, Julien; Bock, Davi; Reid, R Clay; Warfield, Simon K
2007-01-01
3D reconstruction from serial 2D microscopy images depends on non-linear alignment of serial sections. For some structures, such as the neuronal circuitry of the brain, very large images at very high resolution are necessary to permit reconstruction. These very large images prevent the direct use of classical registration methods. We propose in this work a method to deal with the non-linear alignment of arbitrarily large 2D images using the finite support properties of cubic B-splines. After initial affine alignment, each large image is split into a grid of smaller overlapping sub-images, which are individually registered using cubic B-splines transformations. Inside the overlapping regions between neighboring sub-images, the coefficients of the knots controlling the B-splines deformations are blended, to create a virtual large grid of knots for the whole image. The sub-images are resampled individually, using the new coefficients, and assembled together into a final large aligned image. We evaluated the method on a series of large transmission electron microscopy images and our results indicate significant improvements compared to both manual and affine alignment.
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DEFF Research Database (Denmark)
Willatzen, Morten; Duggen, Lars
2017-01-01
In this paper we investigate theoretically the influence of piezoelectric coupling on phonon dispersion relations. Specifically we solve dispersion relations for a fully coupled zinc-blende freestanding quantum well for different orientations of the crystal unit cell. It is shown that the phonon...... mode density in GaAs can change by a factor of approximately 2–3 at qx a = 1 for different crystal-growth directions relative to the slab thickness direction. In particular, it is found that optical and acoustic phonon modes are always piezoelectrically coupled, independent of the crystal...... that the piezoelectric effect leads to a drastically enhanced coupling of acoustic and optical phonon modes and increase in the local phonon density of states near the plasma frequency where the permittivity approaches zero....
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International Nuclear Information System (INIS)
Bialek, B; Lee, J I
2011-01-01
An all electron ab initio method was employed to study the electronic and magnetic properties of the (1 1 0) surface of alkaline-earth metal silicides: CaSi, SrSi and BaSi, in the zinc blende structure. The three surfaces are found to conserve the half-metallic properties of their bulk structures with a wide semiconducting energy gap in the spin-up channel. Half-metallic energy gap at the surfaces is small. In the CaSi surface it is of the order of k B T, which indicates that in the CaSi (1 1 0) a transition to a metallic state is possible due to temperature fluctuations. At the same time, the CaSi surface exhibits the strongest magnetic properties with 0.91 μ B magnetic moment on the Si atom in the topmost layer and 0.21 μ B magnetic moment on the Ca atom. In each of the three surfaces we observe a reduction of magnetic moments on the atoms in the subsurface layer and the enhancement of the magnetic moment on the atoms in the topmost layer, as compared with the properties of atoms in the bulk. An analysis of the calculated total and atom projected densities of states leads to a conclusion that the surface effects in the structures are short-range phenomena
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Interpolation of natural cubic spline
Directory of Open Access Journals (Sweden)
Arun Kumar
1992-01-01
Full Text Available From the result in [1] it follows that there is a unique quadratic spline which bounds the same area as that of the function. The matching of the area for the cubic spline does not follow from the corresponding result proved in [2]. We obtain cubic splines which preserve the area of the function.
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Kwak, Jongheon; Han, Sunghyun; Kim, Jin Kon
2014-03-01
A binary mixture of two block copolymers whose blocks are capable of forming the hydrogen bonding allows one to obtain various microdomains that could not be expected for neat block copolymer. For instance, the binary blend of symmetric polystyrene-block-poly(2-vinylpyridine) copolymer (PS-b-P2VP) and polystyrene-block-polyhydroxystyrene copolymer (PS-b-PHS) blends where the hydrogen bonding occurred between P2VP and PHS showed hexagonally packed (HEX) cylindrical and body centered cubic (BCC) spherical microdomains. To know the exact location of short block copolymer chains at the interface, we synthesized deuterated polystyrene-block-polyhydroxystyrene copolymer (dPS-b-PHS) and prepared a binary mixture with PS-b-P2VP. We investigate, via small angle X-ray scattering (SAXS) and neutron reflectivity (NR), the exact location of shorter dPS block chain near the interface of the microdomains.
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Stefan, Mariana; Vlaicu, Ioana Dorina; Nistor, Leona Cristina; Ghica, Daniela; Nistor, Sergiu Vasile
2017-12-01
We have shown in previous investigations that the low temperature collective magnetism observed in mesoporous cubic ZnS:Mn nanocrystalline powders prepared by colloidal synthesis, with nominal doping concentrations above 0.2 at.%, is due to the formation of Mn2+ clusters with distributed antiferromagnetic coupling localized in an amorphous phase found between the cubic ZnS:Mn nanocrystals. Here we investigate the composition, origin and thermal annealing behavior of this amorphous phase in such a mesoporous ZnS:Mn sample doped with 5 at.% Mn nominal concentration. Correlated analytical transmission electron microscopy, multifrequency electron paramagnetic resonance and Fourier transform infrared spectroscopy data show that the amorphous nanomaterial consists of unreacted precursor hydrated zinc and manganese acetates trapped inside the pores and on the surface of the cubic ZnS nanocrystals. The decomposition of the acetates under isochronal annealing up to 270 °C, where the mesoporous structure is still preserved, lead to changes in the nature and strength of the magnetic interactions between the aggregated Mn2+ ions. These results strongly suggest the possibility to modulate the magnetic properties of such transition metal ions doped II-VI mesoporous structures by varying the synthesis conditions and/or by post-synthesis thermochemical treatments.
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Symptomatic zinc deficiency in experimental zinc deprivation.
Taylor, C M; Goode, H F; Aggett, P J; Bremner, I; Walker, B E; Kelleher, J
1992-01-01
An evaluation of indices of poor zinc status was undertaken in five male subjects in whom dietary zinc intake was reduced from 85 mumol d-1 in an initial phase of the study to 14 mumol d-1. One of the subjects developed features consistent with zinc deficiency after receiving the low zinc diet for 12 days. These features included retroauricular acneform macullo-papular lesions on the face, neck, and shoulders and reductions in plasma zinc, red blood cell zinc, neutrophil zinc and plasma alkal...
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First-principles calculations of a half-metallic ferromagnet zinc blende Zn1−xVxTe
International Nuclear Information System (INIS)
El Amine Monir, M.; Baltache, H.; Khenata, R.; Murtaza, G.; Azam, Sikander; Bouhemadou, A.; Al-Douri, Y.; Bin Omran, S.; Ali, Roshan
2015-01-01
First-principles calculations have been used to study the structural, elastic, electronic, magnetic and thermal properties of zinc blende Zn 1−x V x Te for x=0, 0.25, 0.50, 0.75 and 1 using the full-potential linearized augmented plane wave method (FP-LAPW) based on spin-polarized density functional theory (DFT). The electronic exchange-correlation potential is approached using the spin generalized gradient approximation (spin-GGA). The structural properties of the Zn 1−x V x Te alloys (x=0, 0.25, 0.50, 0.75 and 1) are given for the lattice constants and the bulk moduli and their pressure derivatives. The elastic constants C 11 , C 12 and C 44 are calculated using numerical first-principles calculations implemented in the WIEN2k package. An analysis of the band structures and the densities of states reveals that Zn 0.50 V 0.50 Te and Zn 0.75 V 0.25 Te exhibit a half-metallic character, while Zn 0.25 V 0.75 Te is nearly half-metallic. The band structure calculations are used to estimate the spin-polarized splitting energies Δ x (d) and Δ x (pd) produced by the V(3d)-doped and s(p)–d exchange constants N 0α (conduction band) and N 0β (valence band). The p–d hybridization reduces the magnetic moment of V from its atomic charge value of 3µ B and creates small local magnetic moments on the nonmagnetic Zn and Te sites. Finally, we present the thermal effect on the macroscopic properties of these alloys, such as the thermal expansion coefficient, heat capacity and Debye temperature, based on the quasi-harmonic Debye model. - Highlights: • Some physical properties of Vanadium doped ZnTe have been investigated. • Structural parameters for the parent compounds compare well with the available data. • The elastic and thermal properties are studied for the first time
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DEFF Research Database (Denmark)
Dau, Susanne
2016-01-01
Blended Learning has been implemented, evaluated and researched for the last decades within different educational areas and levels. Blended learning has been coupled with different epistemological understandings and learning theories, but the fundamental character and dimensions of learning...... in blended learning are still insufficient. Moreover, blended learning is a misleading concept described as learning, despite the fact that it fundamentally is an instructional and didactic approach (Oliver & Trigwell, 2005) addressing the learning environment (Inglis, Palipoana, Trenhom & Ward, 2011......) instead of the learning processes behind. Much of the existing research within the field seems to miss this perspective. The consequence is a lack of acknowledgement of the driven forces behind the context and the instructional design limiting the knowledge foundation of learning in blended learning. Thus...
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Cubical sets as a classifying topos
DEFF Research Database (Denmark)
Spitters, Bas
Coquand’s cubical set model for homotopy type theory provides the basis for a computational interpretation of the univalence axiom and some higher inductive types, as implemented in the cubical proof assistant. We show that the underlying cube category is the opposite of the Lawvere theory of De...... Morgan algebras. The topos of cubical sets itself classifies the theory of ‘free De Morgan algebras’. This provides us with a topos with an internal ‘interval’. Using this interval we construct a model of type theory following van den Berg and Garner. We are currently investigating the precise relation...
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Generalized Vaidya spacetime for cubic gravity
Ruan, Shan-Ming
2016-03-01
We present a kind of generalized Vaidya solution of a new cubic gravity in five dimensions whose field equations in spherically symmetric spacetime are always second order like the Lovelock gravity. We also study the thermodynamics of its spherically symmetric apparent horizon and get its entropy expression and generalized Misner-Sharp energy. Finally, we present the first law and second law hold in this gravity. Although all the results are analogous to those in Lovelock gravity, we in fact introduce the contribution of a new cubic term in five dimensions where the cubic Lovelock term is just zero.
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... Consumer Datos en español Health Professional Other Resources Zinc Fact Sheet for Consumers Have a question? Ask ... find out more about zinc? Disclaimer What is zinc and what does it do? Zinc is a ...
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Kaplunov, Mikhail G; Krasnikova, Svetlana S; Nikitenko, Sergey L; Sermakasheva, Natalia L; Yakushchenko, Igor K
2012-04-03
We have investigated the electroluminescence spectra of the electroluminescent devices based on the new zinc complexes of amino-substituted benzothiazoles and quinolines containing the C-N-M-N chains in their chelate cycles. The spectra exhibit strong exciplex bands in the green to yellow region 540 to 590 nm due to interaction of the excited states of zinc complexes and triaryl molecules of the hole-transporting layer. For some devices, the intrinsic luminescence band of 460 nm in the blue region is also observed along with the exciplex band giving rise to an almost white color of the device emission. The exciplex band can be eliminated if the material of the hole-transporting layer is not a triarylamine derivative. We have also found the exciplex emission in the photoluminescence spectra of the films containing blends of zinc complex and triphenylamine material.
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Supporting School Leaders in Blended Learning with Blended Learning
Acree, Lauren; Gibson, Theresa; Mangum, Nancy; Wolf, Mary Ann; Kellogg, Shaun; Branon, Suzanne
2017-01-01
This study provides a mixed-methods case-study design evaluation of the Leadership in Blended Learning (LBL) program. The LBL program uses blended approaches, including face-to-face and online, to prepare school leaders to implement blended learning initiatives in their schools. This evaluation found that the program designers effectively…
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International Nuclear Information System (INIS)
Sahraei, R.; Goudarzi, A.; Ahmadpoor, H.; Motedayen Aval, Gh.
2006-01-01
Zinc sulfide nanocrystalline thin films were prepared by a new chemical bath deposition route on soda lime glass and quartz substrates using a weak acidic bath, in which disodium salt of ethylenediaminetetraacetic acid (EDTA) acts as a complexing agent and thioacetamide acts as a source of sulfide ions. The thickness of the films varied from a few nm to 500 nm. The chemical composition of films was studied by energy-dispersive X-ray analyzer and Fourier transform infrared spectroscopy. The films are very close to Zinc sulfide stoichiometry and we did not observed any organic compounds in the impurity form in them. X-ray diffraction indicates that the film and powder formed in the same reaction bath have cubic zinc blende structure. The films have high transmittance of about 75% in the visible region. The optical band-gap energy (E g ) was determined to be 3.75 eV from the absorption spectrophotometry measurements.
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International Nuclear Information System (INIS)
Krstić, Jelena; Spasojević, Jelena; Radosavljević, Aleksandra; Šiljegovć, Milorad; Kačarević-Popović, Zorica
2014-01-01
In this study, the potential of chitosan/poly(vinyl alcohol) (CS/PVA) blends as capping agent for stabilization of Ag-nanoparticles (Ag NPs) during their in situ gamma irradiation induced synthesis was investigated. The UV–vis absorption spectra show the surface plasmon absorption band around 410 nm, which confirms the formation of Ag-nanoparticles. It was found that the composition of CS/PVA blend affected the size of the obtained Ag-nanoparticles, as well as the parameters such as density, molar concentration and effective surface area, calculated from the experimentally obtained UV–vis absorption spectra and spectra obtained by simulation according to the Mie theory. SEM micrograph and XRD measurement indicated a spherical morphology and face centered cubic crystal structure of Ag-nanoparticles, with diameter around 12 nm. The values of optical band gap energy between valence and conduction bands (E g ), calculated from the UV–vis absorption spectra, also show dependence on the blend composition for Ag–CS/PVA colloids as well as for Ag–CS/PVA nanocomposites. - Highlights: • Ag NPs were synthesized by γ-irradiation and stabilized by CS/PVA blends. • Composition of CS/PVA blends has influence on the size of spherical Ag NPs. • simulation based on Mie theory was used to calculate the parameters of Ag NPs. • Ag NPs are stabilized through interactions with -OH and -NH 2 groups of polymers. • Optical band gap energy was calculated from UV–vis spectra by Tauc's expression
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Bauerová, Andrea
2013-01-01
This thesis is focused on a new approach of education called blended learning. The history and developement of Blended Learning is described in the first part. Then the methods and tools of Blended Learning are evaluated and compared to the traditional methods of education. At the final part an efficient developement of the educational programs is emphasized.
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Spinning solitons in cubic-quintic nonlinear media
Indian Academy of Sciences (India)
Spinning solitons in cubic-quintic nonlinear media ... features of families of bright vortex solitons (doughnuts, or 'spinning' solitons) in both conservative and dissipative cubic-quintic nonlinear media. ... Pramana – Journal of Physics | News.
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Energy Technology Data Exchange (ETDEWEB)
Pires, Homero M.; Mendes, Luis C.; Albitres, Gerson A.V.; Cestari, Sibele P.; Mattos, Gabriela C., E-mail: homero@ima.ufrj.br [Universidade Federal do Rio de Janeiro (IMA/UFRJ), Rio de Janeiro, RJ (Brazil). Instituto de Macromoleculas Professora Eloisa Mano
2015-07-01
The aim of this research was to reuse recycled poly(ethylene terephthalate) (PET) in blend with polycarbonate (PC) in order to avoid UV degradation in outdoor application. Nanocomposite based on blend of recycled (PET) and polycarbonate (PC) in the ratio of 80/20 with nano zinc oxide (ZnO) at different concentrations was prepared. The blend was subjected to ultraviolet (UV) radiation for accelerated aging chamber, we evaluated the effect of the presence nZnO filler as a barrier to UV rays. Dynamic-mechanical analysis (DMA) and nuclear magnetic resonance in the solid state (NMR). It is the degradation retardant effect at concentrations starting from 3% nZnO. (author)
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Koppolu, Ramya
Nanomaterials have diversified applications based on the unique properties. These nanoparticles and functionalized nanocomposites have been studied in the health care filed. Nanoparticles are mostly used in sunscreens which are a part of human life. These sunscreens consist of titanium dioxide and zinc oxide nanoparticles. Due to the higher band crevices, they help the skin to protect from ultraviolet rays, for instance, ultraviolet B and ultraviolet A. A series of nanostructured zinc oxide nanoparticles were prepared by cost-effective chemical and bioinspired methods and variables were optimized. Highly stable and spherical zinc oxide nanoparticles were formulated by aloe vera ( Aloe barbadensis) plant extract and avocado (Persea americana Mill) fruit extract. The state-of-the-art instrumentation was used to characterize the morphology, elemental composition, and particle size distribution. X-ray diffraction data indicated highly crystalline and ultrafine nanoparticles were obtained from the colloidal methods. The X-ray photoelectron spectroscopy results showed the chemical state of zinc, carbon, and oxygen atoms were well-indexed and are used as fingerprint identification of the elements. Transmission electron microscopy images show the shape of particles were cubic and fiber shape contingent upon the protecting operators and heat treatment conditions. The toxicity studies of zinc oxide nanoparticles were found to cause an increase in nitric oxide, which is protecting against further oxidative stress and appears to be nontoxic.
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Dietary phytate, zinc and hidden zinc deficiency.
Sandstead, Harold H; Freeland-Graves, Jeanne H
2014-10-01
Epidemiological data suggest at least one in five humans are at risk of zinc deficiency. This is in large part because the phytate in cereals and legumes has not been removed during food preparation. Phytate, a potent indigestible ligand for zinc prevents it's absorption. Without knowledge of the frequency of consumption of foods rich in phytate, and foods rich in bioavailable zinc, the recognition of zinc deficiency early in the illness may be difficult. Plasma zinc is insensitive to early zinc deficiency. Serum ferritin concentration≤20μg/L is a potential indirect biomarker. Early effects of zinc deficiency are chemical, functional and may be "hidden". The clinical problem is illustrated by 2 studies that involved US Mexican-American children, and US premenopausal women. The children were consuming home diets that included traditional foods high in phytate. The premenopausal women were not eating red meat on a regular basis, and their consumption of phytate was mainly from bran breakfast cereals. In both studies the presence of zinc deficiency was proven by functional responses to controlled zinc treatment. In the children lean-mass, reasoning, and immunity were significantly affected. In the women memory, reasoning, and eye-hand coordination were significantly affected. A screening self-administered food frequency questionnaire for office might help caregiver's identify patients at risk of zinc deficiency. Copyright © 2014 Elsevier GmbH. All rights reserved.
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ZnSe/ZnSeTe Superlattice Nanotips
Directory of Open Access Journals (Sweden)
Young SJ
2010-01-01
Full Text Available Abstract The authors report the growth of ZnSe/ZnSeTe superlattice nanotips on oxidized Si(100 substrate. It was found the nanotips exhibit mixture of cubic zinc-blende and hexagonal wurtzite structures. It was also found that photoluminescence intensities observed from the ZnSe/ZnSeTe superlattice nanotips were much larger than that observed from the homogeneous ZnSeTe nanotips. Furthermore, it was found that activation energies for the ZnSe/ZnSeTe superlattice nanotips with well widths of 16, 20, and 24 nm were 76, 46, and 19 meV, respectively.
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Advanced Branching Control and Characterization of Inorganic Semiconducting Nanocrystals
Energy Technology Data Exchange (ETDEWEB)
Hughes, Steven Michael [Univ. of California, Berkeley, CA (United States)
2007-01-01
The ability to finely tune the size and shape of inorganic semiconducting nanocrystals is an area of great interest, as the more control one has, the more applications will be possible for their use. The first two basic shapes develped in nanocrystals were the sphere and the anistropic nanorod. the II_VI materials being used such as Cadmium Selenide (CdSe) and Cadmium Telluride (CdTe), exhibit polytypism, which allows them to form in either the hexagonally packed wurtzite or cubically packed zinc blende crystalline phase. The nanorods are wurtzite with the length of the rod growing along the c-axis. As this grows, stacking faults may form, which are layers of zinc blende in the otherwise wurtzite crystal. Using this polytypism, though, the first generation of branched crystals were developed in the form of the CdTe tetrapod. This is a nanocrystal that nucleates in the zincblend form, creating a tetrahedral core, on which four wurtzite arms are grown. This structure opened up the possibility of even more complex shapes and applications. This disseration investigates the advancement of branching control and further understanding the materials polytypism in the form of the stacking faults in nanorods.
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Relations between blended learning possibilities and teachers' approaches to blended learning
DEFF Research Database (Denmark)
Stenalt, Maria Hvid; Nielsen, Tobias Alsted; Bager-Elsborg, Anna
Higher Education has embraced blended learning as a way of enhancing quality in teaching and helping students to learn. This presentation addresses relations between blended learning possiblities presented to teachers in a teacher training project and teachers’ approaches to blended learning. We...... suggest that in order to identify the level of impact of integrating technologies in teaching and learning, we need to understand the factors influencing approaches to design of courses for blended contexts. Participants in the teacher training project come from the Department of Law at Aarhus University......: • Optain locally-embedded knowledge about blended learning • Develop opportunities for law students to receive (more) feedback • Comply with strategic aims The results so far suggest that teachers provide a disciplinary perspective on the key dimensions of blended learning, which influences...
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Energy Technology Data Exchange (ETDEWEB)
Hickey, Robert J.; Gillard, Timothy M.; Irwin, Matthew T.; Morse, David C.; Lodge, Timothy P.; Bates, Frank S. (UMM)
2016-10-13
We have established the existence of a line of congruent first-order lamellar-to-disorder (LAM–DIS) transitions when appropriate amounts of poly(cyclohexylethylene) (C) and poly(ethylene) (E) homopolymers are mixed with a corresponding compositionally symmetric CE diblock copolymer. The line of congruent transitions, or the congruent isopleth, terminates at the bicontinuous microemulsion (BμE) channel, and its trajectory appears to be influenced by the critical composition of the C/E binary homopolymer blend. Blends satisfying congruency undergo a direct LAM–DIS transition without passing through a two-phase region. We present complementary optical transmission, small-angle X-ray scattering (SAXS), transmission electron microscopy (TEM), and dynamic mechanical spectroscopy (DMS) results that establish the phase behavior at constant copolymer volume fraction and varying C/E homopolymer volume ratios. Adjacent to the congruent composition at constant copolymer volume fraction, the lamellar and disordered phases are separated by two-phase coexistence windows, which converge, along with the line of congruent transitions, at an overall composition in the phase prism coincident with the BμE channel. Hexagonal and cubic (double gyroid) phases occur at higher diblock copolymer concentrations for asymmetric amounts of C and E homopolymers. These results establish a quantitative method for identifying the detailed phase behavior of ternary diblock copolymer–homopolymer blends, especially in the vicinity of the BμE.
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Sol-Gel Synthesis and Characterization of Cubic Bismuth Zinc Niobium Oxide Nanopowders
Directory of Open Access Journals (Sweden)
Ganchimeg Perenlei
2014-01-01
Full Text Available Bismuth zinc niobium oxide (BZN was successfully synthesized by a diol-based sol-gel reaction utilizing metal acetate and alkoxide precursors. Thermal analysis of a liquid suspension of precursors suggests that the majority of organic precursors decompose at temperatures up to 150°C, and organic free powders form above 350°C. The experimental results indicate that a homogeneous gel is obtained at about 200°C and then converts to a mixture of intermediate oxides at 350–400°C. Finally, single-phased BZN powders are obtained between 500 and 900°C. The degree of chemical homogeneity as determined by X-ray diffraction and EDS mapping is consistent throughout the samples. Elemental analysis indicates that the atomic ratio of metals closely matches a Bi1.5ZnNb1.5O7 composition. Crystallite sizes of the BZN powders calculated from the Scherrer equation are about 33–98 nm for the samples prepared at 500–700°C, respectively. The particle and crystallite sizes increase with increased sintering temperature. The estimated band gap of the BZN nanopowders from optical analysis is about 2.60–2.75 eV at 500-600°C. The observed phase formations and measured results in this study were compared with those of previous reports.
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A Note on Cubic Convolution Interpolation
Meijering, E.; Unser, M.
2003-01-01
We establish a link between classical osculatory interpolation and modern convolution-based interpolation and use it to show that two well-known cubic convolution schemes are formally equivalent to two osculatory interpolation schemes proposed in the actuarial literature about a century ago. We also discuss computational differences and give examples of other cubic interpolation schemes not previously studied in signal and image processing.
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Van der Baaren, John
2009-01-01
Van der Baaren, J. (2009). Blended Learning. Presentation given at the Mini symposium 'Blended Learning the way to go?'. November, 5, 2009, The Hague, The Netherlands: Netherlands Defence Academy (NDLA).
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On q-power cycles in cubic graphs
DEFF Research Database (Denmark)
Bensmail, Julien
2017-01-01
In the context of a conjecture of Erdos and Gyárfás, we consider, for any q ≥ 2, the existence of q-power cycles (i.e. with length a power of q) in cubic graphs. We exhibit constructions showing that, for every q ≥ 3, there exist arbitrarily large cubic graphs with no q-power cycles. Concerning...... the remaining case q = 2 (which corresponds to the conjecture of Erdos and Gyárfás), we show that there exist arbitrarily large cubic graphs whose only 2-power cycles have length 4 only, or 8 only....
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Energy Technology Data Exchange (ETDEWEB)
Allen, Scott D.; Naik, Sanjeev
2017-08-22
The present invention provides, among other things, extruded blends of aliphatic polycarbonates and polyolefins. In one aspect, provided blends comprise aliphatic polycarbonates such as poly(propylene carbonate) and a lesser amount of a crystalline or semicrystalline polymer. In certain embodiments, provided blends are characterized in that they exhibit unexpected improvements in their elongation properties. In another aspect, the invention provides methods of making such materials and applications of the materials in applications such as the manufacture of consumer packaging materials.
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DEFF Research Database (Denmark)
Staugaard, Hans Jørgen
2012-01-01
Forsøg på at indkredse begrebet blended learning i forbindelse med forberedelsen af projekt FlexVid.......Forsøg på at indkredse begrebet blended learning i forbindelse med forberedelsen af projekt FlexVid....
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[Improvement in zinc nutrition due to zinc transporter-targeting strategy].
Kambe, Taiho
2016-07-01
Adequate intake of zinc from the daily diet is indispensable to maintain health. However, the dietary zinc content often fails to fulfill the recommended daily intake, leading to zinc deficiency and also increases the risk of developing chronic diseases, particularly in elderly individuals. Therefore, increased attention is required to overcome zinc deficiency and it is important to improve zinc nutrition in daily life. In the small intestine, the zinc transporter, ZIP4, functions as a component that is essential for zinc absorption. In this manuscript, we present a brief overview regarding zinc deficiency. Moreover, we review a novel strategy, called "ZIP4-targeting", which has the potential to enable efficient zinc absorption from the diet. ZIP4-targeting strategy is possibly a major step in preventing zinc deficiency and improving human health.
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International Nuclear Information System (INIS)
Boeckner, L.S.; Kies, C.
1986-01-01
The objective of the study was to determine the effects of feeding zinc sufficient and zinc deficient rations on taste sensitivity and zinc contents of selected organs in rats. The 36 Sprague-Dawley male weanling rats were divided into 2 groups and fed zinc deficient or zinc adequate rations. The animals were subjected to 4 trial periods in which a choice of deionized distilled water or a solution of quinine sulfate at 1.28 x 10 -6 was given. A randomized schedule for rat sacrifice was used. No differences were found between zinc deficient and zinc adequate rats in taste preference aversion scores for quinine sulfate in the first three trial periods; however, in the last trial period rats in the zinc sufficient group drank somewhat less water containing quinine sulfate as a percentage of total water consumption than did rats fed the zinc deficient ration. Significantly higher zinc contents of kidney, brain and parotid salivary glands were seen in zinc adequate rats compared to zinc deficient rats at the end of the study. However, liver and tongue zinc levels were lower for both groups at the close of the study than were those of rats sacrificed at the beginning of the study
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Shape Preserving Interpolation Using C2 Rational Cubic Spline
Directory of Open Access Journals (Sweden)
Samsul Ariffin Abdul Karim
2016-01-01
Full Text Available This paper discusses the construction of new C2 rational cubic spline interpolant with cubic numerator and quadratic denominator. The idea has been extended to shape preserving interpolation for positive data using the constructed rational cubic spline interpolation. The rational cubic spline has three parameters αi, βi, and γi. The sufficient conditions for the positivity are derived on one parameter γi while the other two parameters αi and βi are free parameters that can be used to change the final shape of the resulting interpolating curves. This will enable the user to produce many varieties of the positive interpolating curves. Cubic spline interpolation with C2 continuity is not able to preserve the shape of the positive data. Notably our scheme is easy to use and does not require knots insertion and C2 continuity can be achieved by solving tridiagonal systems of linear equations for the unknown first derivatives di, i=1,…,n-1. Comparisons with existing schemes also have been done in detail. From all presented numerical results the new C2 rational cubic spline gives very smooth interpolating curves compared to some established rational cubic schemes. An error analysis when the function to be interpolated is ft∈C3t0,tn is also investigated in detail.
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Polystyrene/Hyperbranched Polyester Blends and Reactive Polystyrene/Hyperbranched Polyester Blends
National Research Council Canada - National Science Library
Mulkern, Thomas
1999-01-01
.... In this work, the incorporation of HBPs in thermoplastic blends was investigated. Several volume fractions of hydroxyl functionalized hyperbranched polyesters were melt blended with nonreactive polystyrene (PS...
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DEFF Research Database (Denmark)
Birkedal, Lars; Bizjak, Aleš; Clouston, Ranald
2016-01-01
This paper improves the treatment of equality in guarded dependent type theory (GDTT), by combining it with cubical type theory (CTT). GDTT is an extensional type theory with guarded recursive types, which are useful for building models of program logics, and for programming and reasoning...... with coinductive types. We wish to implement GDTT with decidable type-checking, while still supporting non-trivial equality proofs that reason about the extensions of guarded recursive constructions. CTT is a variation of Martin-L\\"of type theory in which the identity type is replaced by abstract paths between...... terms. CTT provides a computational interpretation of functional extensionality, is conjectured to have decidable type checking, and has an implemented type-checker. Our new type theory, called guarded cubical type theory, provides a computational interpretation of extensionality for guarded recursive...
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DEFF Research Database (Denmark)
Birkedal, Lars; Bizjak, Aleš; Clouston, Ranald
2016-01-01
This paper improves the treatment of equality in guarded dependent type theory (GDTT), by combining it with cubical type theory (CTT). GDTT is an extensional type theory with guarded recursive types, which are useful for building models of program logics, and for programming and reasoning...... with coinductive types. We wish to implement GDTT with decidable type checking, while still supporting non-trivial equality proofs that reason about the extensions of guarded recursive constructions. CTT is a variation of Martin-L\\"of type theory in which the identity type is replaced by abstract paths between...... terms. CTT provides a computational interpretation of functional extensionality, enjoys canonicity for the natural numbers type, and is conjectured to support decidable type-checking. Our new type theory, guarded cubical type theory (GCTT), provides a computational interpretation of extensionality...
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Talsma, Elise F; Moretti, Diego; Ly, Sou Chheng; Dekkers, Renske; van den Heuvel, Ellen Ghm; Fitri, Aditia; Boelsma, Esther; Stomph, Tjeerd Jan; Zeder, Christophe; Melse-Boonstra, Alida
2017-06-01
Background: Milk has been suggested to increase zinc absorption. The effect of processing and the ability of milk to enhance zinc absorption from other foods has not been measured directly in humans. Objective: We aimed to assess zinc absorption from 1 ) milk undergoing various processing and preparatory steps and 2 ) from intrinsically labeled high-phytate rice consumed with milk or water. Methods: Two randomized crossover studies were conducted in healthy young women [age:18-25 y; body mass index (in kg/m 2 ): 20-25]: 1 ) a milk study ( n = 19) comparing the consumption of 800 mL full-fat ultra-high temperature (UHT) milk [heat-treated milk (HTM)], full-fat UHT milk diluted 1:1 with water [heat-treated milk and water (MW)], water, or unprocessed (raw) milk (UM), each extrinsically labeled with 67 Zn, and 2 ) a rice study ( n = 18) comparing the consumption of 90 g intrinsically 67 Zn-labeled rice with 600 mL of water [rice and water (RW)] or full-fat UHT milk [rice and milk (RM)]. The fractional absorption of zinc (FAZ) was measured with the double-isotope tracer ratio method. In vitro, we assessed zinc extraction from rice blended into water, UM, or HTM with or without phytate. Results: FAZ from HTM was 25.5% (95% CI: 21.6%, 29.4%) and was not different from UM (27.8%; 95% CI: 24.2%, 31.4%). FAZ from water was higher (72.3%; 95% CI: 68.7%, 75.9%), whereas FAZ from MW was lower (19.7%; 95% CI: 17.5%, 21.9%) than HTM and UM (both P zinc from rice with HTM than from rice with water at various phytate concentrations. Conclusions: Milk enhanced human FAZ from high-phytate rice by 62% compared with water. Diluting milk with water decreases its absorption-enhancing proprieties, whereas UHT processing does not. This trial was registered at the Dutch trial registry as NTR4267 (http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=4267). © 2017 American Society for Nutrition.
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Randomized Block Cubic Newton Method
Doikov, Nikita; Richtarik, Peter
2018-01-01
We study the problem of minimizing the sum of three convex functions: a differentiable, twice-differentiable and a non-smooth term in a high dimensional setting. To this effect we propose and analyze a randomized block cubic Newton (RBCN) method, which in each iteration builds a model of the objective function formed as the sum of the natural models of its three components: a linear model with a quadratic regularizer for the differentiable term, a quadratic model with a cubic regularizer for the twice differentiable term, and perfect (proximal) model for the nonsmooth term. Our method in each iteration minimizes the model over a random subset of blocks of the search variable. RBCN is the first algorithm with these properties, generalizing several existing methods, matching the best known bounds in all special cases. We establish ${\\cal O}(1/\\epsilon)$, ${\\cal O}(1/\\sqrt{\\epsilon})$ and ${\\cal O}(\\log (1/\\epsilon))$ rates under different assumptions on the component functions. Lastly, we show numerically that our method outperforms the state-of-the-art on a variety of machine learning problems, including cubically regularized least-squares, logistic regression with constraints, and Poisson regression.
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Randomized Block Cubic Newton Method
Doikov, Nikita
2018-02-12
We study the problem of minimizing the sum of three convex functions: a differentiable, twice-differentiable and a non-smooth term in a high dimensional setting. To this effect we propose and analyze a randomized block cubic Newton (RBCN) method, which in each iteration builds a model of the objective function formed as the sum of the natural models of its three components: a linear model with a quadratic regularizer for the differentiable term, a quadratic model with a cubic regularizer for the twice differentiable term, and perfect (proximal) model for the nonsmooth term. Our method in each iteration minimizes the model over a random subset of blocks of the search variable. RBCN is the first algorithm with these properties, generalizing several existing methods, matching the best known bounds in all special cases. We establish ${\\\\cal O}(1/\\\\epsilon)$, ${\\\\cal O}(1/\\\\sqrt{\\\\epsilon})$ and ${\\\\cal O}(\\\\log (1/\\\\epsilon))$ rates under different assumptions on the component functions. Lastly, we show numerically that our method outperforms the state-of-the-art on a variety of machine learning problems, including cubically regularized least-squares, logistic regression with constraints, and Poisson regression.
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Does the oral zinc tolerance test measure zinc absorption
Energy Technology Data Exchange (ETDEWEB)
Valberg, L.S.; Flanagan, P.R.; Brennan, J.; Chamberlain, M.J.
1985-01-01
Increases in plasma zinc concentration were compared with radiozinc absorption after oral test doses. Ten healthy, fasting subjects were each given 385 mumol zinc chloride (25 mg Zn) labelled with 0.5 muCi /sup 65/ZnCl/sub 2/ and a non-absorbed marker, /sup 51/CrCl/sub 3/, dissolved in 100 ml of water; another 10 persons were given 354 mumol zinc chloride and 125 g of minced turkey containing 31 mumol zinc also labelled with /sup 65/Zn and /sup 51/Cr. Measurements were made of plasma zinc concentration at hourly intervals for 5 hours, radiozinc absorption by stool counting of unabsorbed radioactivity 12-36 hours later, and radiozinc retention by whole body counting at 7 days. The mean percentage of radiozinc absorbed and retained in the body from the two test meals was found to be identical (42%). In contrast the increased area under the plasma zinc curve up to 5 hours after the turkey meal, 28 +/- 9 mumol/L (mean +/- SD) was significantly less than that for zinc chloride alone, 47 +/- 15 mumol/L, p less than 0.005. Despite this difference, a good correlation was found between the area under the plasma zinc curve and /sup 65/Zn absorption in individual subjects after each meal. The discrepancy between the results of zinc absorption derived from the plasma zinc curve and /sup 65/Zn absorption for the liquid and solid test meals was most likely explained by binding of zinc to food and delayed gastric emptying of the solid meal. With a test meal of turkey meat at least this dampened the plasma appearance of zinc but did not affect its overall absorption.
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Does the oral zinc tolerance test measure zinc absorption
International Nuclear Information System (INIS)
Valberg, L.S.; Flanagan, P.R.; Brennan, J.; Chamberlain, M.J.
1985-01-01
Increases in plasma zinc concentration were compared with radiozinc absorption after oral test doses. Ten healthy, fasting subjects were each given 385 mumol zinc chloride (25 mg Zn) labelled with 0.5 muCi 65 ZnCl 2 and a non-absorbed marker, 51 CrCl 3 , dissolved in 100 ml of water; another 10 persons were given 354 mumol zinc chloride and 125 g of minced turkey containing 31 mumol zinc also labelled with 65 Zn and 51 Cr. Measurements were made of plasma zinc concentration at hourly intervals for 5 hours, radiozinc absorption by stool counting of unabsorbed radioactivity 12-36 hours later, and radiozinc retention by whole body counting at 7 days. The mean percentage of radiozinc absorbed and retained in the body from the two test meals was found to be identical (42%). In contrast the increased area under the plasma zinc curve up to 5 hours after the turkey meal, 28 +/- 9 mumol/L (mean +/- SD) was significantly less than that for zinc chloride alone, 47 +/- 15 mumol/L, p less than 0.005. Despite this difference, a good correlation was found between the area under the plasma zinc curve and 65 Zn absorption in individual subjects after each meal. The discrepancy between the results of zinc absorption derived from the plasma zinc curve and 65 Zn absorption for the liquid and solid test meals was most likely explained by binding of zinc to food and delayed gastric emptying of the solid meal. With a test meal of turkey meat at least this dampened the plasma appearance of zinc but did not affect its overall absorption
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Neutrosophic Cubic MCGDM Method Based on Similarity Measure
Directory of Open Access Journals (Sweden)
Surapati Pramanik
2017-06-01
Full Text Available The notion of neutrosophic cubic set is originated from the hybridization of the concept of neutrosophic set and interval valued neutrosophic set. We define similarity measure for neutrosophic cubic sets and prove some of its basic properties.
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Cubical version of combinatorial differential forms
DEFF Research Database (Denmark)
Kock, Anders
2010-01-01
The theory of combinatorial differential forms is usually presented in simplicial terms. We present here a cubical version; it depends on the possibility of forming affine combinations of mutual neighbour points in a manifold, in the context of synthetic differential geometry.......The theory of combinatorial differential forms is usually presented in simplicial terms. We present here a cubical version; it depends on the possibility of forming affine combinations of mutual neighbour points in a manifold, in the context of synthetic differential geometry....
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Kessels, Jana Elena; Wessels, Inga; Haase, Hajo; Rink, Lothar; Uciechowski, Peter
2016-09-01
The distribution of intracellular zinc, predominantly regulated through zinc transporters and zinc binding proteins, is required to support an efficient immune response. Epigenetic mechanisms such as DNA methylation are involved in the expression of these genes. In demethylation experiments using 5-Aza-2'-deoxycytidine (AZA) increased intracellular (after 24 and 48h) and total cellular zinc levels (after 48h) were observed in the myeloid cell line HL-60. To uncover the mechanisms that cause the disturbed zinc homeostasis after DNA demethylation, the expression of human zinc transporters and zinc binding proteins were investigated. Real time PCR analyses of 14 ZIP (solute-linked carrier (SLC) SLC39A; Zrt/IRT-like protein), and 9 ZnT (SLC30A) zinc transporters revealed significantly enhanced mRNA expression of the zinc importer ZIP1 after AZA treatment. Because ZIP1 protein was also enhanced after AZA treatment, ZIP1 up-regulation might be the mediator of enhanced intracellular zinc levels. The mRNA expression of ZIP14 was decreased, whereas zinc exporter ZnT3 mRNA was also significantly increased; which might be a cellular reaction to compensate elevated zinc levels. An enhanced but not significant chromatin accessibility of ZIP1 promoter region I was detected by chromatin accessibility by real-time PCR (CHART) assays after demethylation. Additionally, DNA demethylation resulted in increased mRNA accumulation of zinc binding proteins metallothionein (MT) and S100A8/S100A9 after 48h. MT mRNA was significantly enhanced after 24h of AZA treatment also suggesting a reaction of the cell to restore zinc homeostasis. These data indicate that DNA methylation is an important epigenetic mechanism affecting zinc binding proteins and transporters, and, therefore, regulating zinc homeostasis in myeloid cells. Copyright © 2016 Elsevier GmbH. All rights reserved.
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P-union and P-intersection of neutrosophic cubic sets
Florentin Smarandache; Chang Su Kim
2015-01-01
Conditions for the P-intersection and P-intersection of falsity-external (resp. indeterminacy-external and truth-external) neutrosophic cubic sets to be an falsity-external (resp. indeterminacy-external and truth- external) neutrosophic cubic set are provided. Conditions for the P-union and the P-intersection of two truth-external (resp. indeterminacy-external and falsity-external) neutrosophic cubic sets to be a truth-internal (resp. indeterminacy-internal and falsity-internal) neutrosoph...
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Bos, Nynke; Brand-Gruwel, Saskia
2018-01-01
Blended learning is often associated with student-oriented learning in which students have varying degrees of control over their learning process. However, the current notion of blended learning is often a teacher- oriented approach in which the teacher identifies the used learning technologies and
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Effect of blending temperature on the mechanical properties of PVC/ENR blend upon irradiation
International Nuclear Information System (INIS)
Chantara Thevy Ratnam; Khairul Zaman Mohd Dahlan; Nasir, M.; Baharin, A.
2000-01-01
Poly (vinyl chloride) / epoxidized natural rubber blends were prepared with a Brabender plasticorder at 140, 150, 160, 170 and 180 degree C mixing temperatures. They were mixed at 50 rpm rotor speed for 10 min. The blends were irradiated with doses ranging from 0-200 kGy. Changes in tensile strength, modulus at 100% elongation, gel fraction and damping properties (tan δ) of the blends with increasing mixing temperatures and irradiation doses were investigated. In general, it was observed that the mixing temperature is important in maximizing the positive effect of irradiation. Results revealed that a readily miscible blend enjoy maximum benefit from irradiation meanwhile irradiation impart miscibility to a partially miscible PVC/ENR blend. The enhancement in blend properties is believed to be attributed by the irradiation-induced crosslinking along with irradiation-induced interaction between the polymers. The radiation-induced degradation found to be prominent at higher doses for blend that has undergone excessive thermal degradation. However evidence did not reveal the specific nature of radiation-induced reaction responsible for the improved interactions of the blends. (author)
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Blending Words Found In Social Media
Directory of Open Access Journals (Sweden)
Giyatmi Giyatmi
2017-12-01
Full Text Available There are many new words from the social media such as Netizen, Trentop, and Delcon. Those words include in blending. Blending is one of word formations combining two clipped words to form a brand new word. The researchers are interested in analyzing blend words used in the social media such as Instagram, Twitter, Facebook, and Blackberry Messenger. This research aims at (1 finding blend words used in the social media (2 describing kinds of blend words used in social media (3 describing the process of blend word formation used in the social media. This research uses some theories dealing with definition of blending and kinds of blending. This research belongs to descriptive qualitative research. Data of the research are English blend words used in social media. Data sources of this research are websites consisting of some English words used in social media and some social media users as the informant. Techniques of data collecting in this research are observation and simak catat. Observation is by observing some websites consisting of some English words used in social media. Simak catat is done by taking some notes on the data and encoding in symbols such as No/Blend words/Kinds of Blending. The researchers use source triangulation to check the data from the researchers with the informant and theory triangulation to determine kinds of blending and blend word formation in social media. There are115 data of blend words. Those data consists of 65 data of Instagram, 47 data of Twitter, 1 datum of Facebook, and 2 data of Blackberry Messenger. There are 2 types of blending used in social media;108 data of blending with clipping and 7 data of blending with overlapping. There are 10 ways of blend word formation found in this research.
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Method of capturing or trapping zinc using zinc getter materials
Hunyadi Murph, Simona E.; Korinko, Paul S.
2017-07-11
A method of trapping or capturing zinc is disclosed. In particular, the method comprises a step of contacting a zinc vapor with a zinc getter material. The zinc getter material comprises nanoparticles and a metal substrate.
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Design Principles for the Blend in Blended Learning: A Collective Case Study
Lai, Ming; Lam, Kwok Man; Lim, Cher Ping
2016-01-01
This paper reports on a collective case study of three blended courses taught by different instructors in a higher education institution, with the purpose of identifying the different types of blend and how the blend supports student learning. Based on the instructors' and students' interviews, and document analysis of course outlines, two major…
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Non-spherical micelles in an oil-in-water cubic phase
DEFF Research Database (Denmark)
Leaver, M.; Rajagopalan, V.; Ulf, O.
2000-01-01
phase, both with and without SDS, was established by NMR self-diffusion. In addition H-2 NMR relaxation experiments have demonstrated that the micelles in the cubic phase are non-spherical, having grown and changed shape upon formation of the cubic phase from the micellar solution. Small angle...... associated with the micellar cubic phase, Pm3n and Fd3m. The micellar volumes calculated for these space groups are similar and are consistent with a change in micellar geometry from spherical to prolate.......The cubic phase formed between the microemulsion and hexagonal phases of the ternary pentaethylene glycol dodecyl ether (C12E5)-decane-water system and that doped with small amounts of sodium dodecylsulfate (SDS) have been investigated. The presence of discrete oil-swollen micelles in the cubic...
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Waghadkar, Yogesh; Arbuj, Sudhir; Shinde, Manish; Ballal, Reshma; Rane, Sunit B.; Gosavi, Suresh; Fouad, H.; Chauhan, Ratna
2018-02-01
In this work, we reported the synthesis of zinc sulphide microspheres using the hydrothermal method. ZnS microspheres were synthesized using water, zinc acetate, thiourea and ammonia solution at 150°C for 6 h, 12 h, and 24 h. The as-synthesized ZnS powders were characterized by x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and ultraviolet-visible (UV-Vis) spectroscopy. XRD indicates the cubic (major phase) as well as hexagonal (minor phase) crystalline phase with enhanced crystallinity increased gradually with more reaction time. UV-Vis spectra show the absorption peaks in the UV-Vis region for all the samples. The Tauc's plot was used to calculate the band gap energy of ZnS samples, which are found to be 3.39 eV, 3.4 eV, and 3.42 eV for the samples synthesized at reaction times of 6 h, 12 h, and 24 h, respectively. FESEM images confirm the formation of microspheres as aggregates of spherical nanoparticles. The as-synthesized ZnS microspheres have been explored for solar light-induced photo-catalytic dye degradation of methylene blue (MB), and the results confirm that such microspheres exhibit effectual photocatalytic properties.
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The bioavailability of four zinc oxide sources and zinc sulphate in broiler chickens
Veldkamp, T.; Diepen, van, J.T.M.; Bikker, P.
2014-01-01
Zinc is an essential trace element for all farm animal species. It is commonly included in animal diets as zinc oxide, zinc sulphate or organically bound zinc. Umicore Zinc Chemicals developed zinc oxide products with different mean particle sizes. Umicore Zinc Chemicals requested Wageningen UR Livestock Research to determine the bioavailability of four zinc oxide sources and zinc sulphate in broiler chickens. A precise estimate of the bioavailability of zinc sources is required both for fulf...
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Directory of Open Access Journals (Sweden)
Dirk König
2016-08-01
Full Text Available Semiconductor nanocrystals (NCs experience stress and charge transfer by embedding materials or ligands and impurity atoms. In return, the environment of NCs experiences a NC stress response which may lead to matrix deformation and propagated strain. Up to now, there is no universal gauge to evaluate the stress impact on NCs and their response as a function of NC size dNC. I deduce geometrical number series as analytical tools to obtain the number of NC atoms NNC(dNC[i], bonds between NC atoms Nbnd(dNC[i] and interface bonds NIF(dNC[i] for seven high symmetry zinc-blende (zb NCs with low-index faceting: {001} cubes, {111} octahedra, {110} dodecahedra, {001}-{111} pyramids, {111} tetrahedra, {111}-{001} quatrodecahedra and {001}-{111} quadrodecahedra. The fundamental insights into NC structures revealed here allow for major advancements in data interpretation and understanding of zb- and diamond-lattice based nanomaterials. The analytical number series can serve as a standard procedure for stress evaluation in solid state spectroscopy due to their deterministic nature, easy use and general applicability over a wide range of spectroscopy methods as well as NC sizes, forms and materials.
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LDPE/PHB blends filled with castor oil cake
Burlein, Gustavo A.; Rocha, Marisa C. G.
2015-05-01
The response surface methodology (RSM) is a collection of mathematical techniques useful for developing, improving and optimizing process. In this study, RSM technique was applied to evaluate the effect of the components proportion on the mechanical properties of low density polyethylene (LDPE)/ poly (3-hydroxy-butyrate) (PHB) blends filled with castor oil cake (CC). The blends were prepared by melt mixing in a twin screw extruder. Low density polyethylene, poly (3-hydroxy-butyrate) and castor oil pressed cake were represented by the input variables designated as LDPE, PHB and CC, respectively. As it was desirable to consider the largest LDPE content in the ternary system, the components of the mixture were subjected to the following constraints: 0.7 ≤ LDPE ≤ 1.0, 0≤ PHB≤0.3 e 0 ≤ CC ≤0.3. The mechanical properties of the different mixtures were determined by conventional ASTM tests and were evaluated through analysis of variance performed by the Minitab software. Some polynomial equations were tested in order to describe the mechanical behavior of the samples. The quadratic model in pseudo components was selected for describing the tensile behavior because it was the most efficient from a statistical point of view (p-value ≤ 0.05; coefficient of determination (r2) close to 1 and variation inflation factor (VIF) values PHB or CC. The tensile strength values of binary mixtures of LDPE lie in the range from 8.9 to 10 MPa. As some commercial grades of LDPE have mechanical strength in this range, it may be inferred that the addition of a certain amount of PHB or CC to LDPE may be considered as a possibility for obtaining LDPE based materials with increased susceptibility to biodegradation. The cubic model in pseudo components was selected for describe the flexural strength of the samples because it was the most adequate from a statistical point of view. However, the linear model in pseudo components was the most efficient to describe the flexural modulus
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Blended acquisition with dispersed source arrays
Berkhout, A.J.
2012-01-01
Blended source arrays are historically configured with equal source units, such as broadband vibrators (land) and broadband air-gun arrays (marine). I refer to this concept as homogeneous blending. I have proposed to extend the blending concept to inhomogeneous blending, meaning that a blended
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Zinc sulfide thin films deposited by RF reactive sputtering for photovoltaic applications
International Nuclear Information System (INIS)
Shao Lexi; Chang, K.-H.; Hwang, H.-L.
2003-01-01
Zinc sulfide (ZnS) thin films with nano-scale grains of about 50 nm were deposited on glass substrates at a substrate temperature of 200 deg. C via RF reactive sputtering by using zinc plate target and hydrogen sulfide gas. The structure, compositions, electrical and optical characteristics of the deposited films were investigated for the photovoltaic device applications. All films showed a near stoichiometric composition as indicated in their AES data. Distinct single crystalline phase with preferential orientation along the (0 0 0 1) plane of wurtzite or the (1 1 1) plane of zinc blende (ZB) was revealed in their X-ray diffraction (XRD) patterns, and the spacing of the planes are well matched to those of (1 1 2) plane of the chalcopyrite CuInS 2 (CIS). UV-Vis measurement showed that the films had more than 65% transmittance in the wavelength larger than 350 nm, and the fundamental absorption edge shifted to shorter wavelength with the increase of sulfur incorporated in the films, which corresponds to an increase in the energy band gap ranging from 3.59 to 3.72 eV. It was found that ZnS films are suitable for use as the buffer layer of the CIS solar cells, and it is the viable alternative for replacing CdS in the photovoltaic cell structure
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Bifurcation of limit cycles for cubic reversible systems
Directory of Open Access Journals (Sweden)
Yi Shao
2014-04-01
Full Text Available This article is concerned with the bifurcation of limit cycles of a class of cubic reversible system having a center at the origin. We prove that this system has at least four limit cycles produced by the period annulus around the center under cubic perturbations
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Zinc electrode - its behaviour in the nickel oxide-zinc accumulator
Energy Technology Data Exchange (ETDEWEB)
1984-01-01
Certain aspects of zinc electrode reaction and behavior are investigated in view of their application to batteries. The properties of the zinc electrode in a battery system are discussed, emphasizing porous structure. Shape change is emphasized as the most important factor leading to limited battery cycle life. It is shown that two existing models of shape change based on electroosmosis and current distribution are unable to consistently describe observed phenomena. The first stages of electrocrystallization are studied and the surface reactions between the silver substrate and the deposited zinc layer are investigated. The reaction mechanism of zinc and amalgamated zinc in an alkaline electrolyte is addressed, and the batter system is studied to obtain information on cycling behavior and on the shape change phenomenon. The effect on cycle behavior of diferent amalgamation techniques of the zinc electrode and several additives is addressed. Impedance measurements on zinc electrodes are considered, and battery behavior is correlated with changes in the zinc electrode during cycling. 193 references.
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Imbriale, Ryan
2013-01-01
Teachers always have been and always will be the essential element in the classroom. They can create magic inside four walls, but they have never been able to create learning environments outside the classroom like they can today, thanks to blended learning. Blended learning allows students and teachers to break free of the isolation of the…
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The bioavailability of four zinc oxide sources and zinc sulphate in broiler chickens
Veldkamp, T.; Diepen, van J.T.M.; Bikker, P.
2014-01-01
Zinc is an essential trace element for all farm animal species. It is commonly included in animal diets as zinc oxide, zinc sulphate or organically bound zinc. Umicore Zinc Chemicals developed zinc oxide products with different mean particle sizes. Umicore Zinc Chemicals requested Wageningen UR
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Apparatus for blending small particles
International Nuclear Information System (INIS)
Bradley, R.A.; Reese, C.R.; Sease, J.D.
1975-01-01
An apparatus is described for blending small particles and uniformly loading the blended particles in a receptacle. Measured volumes of various particles are simultaneously fed into a funnel to accomplish radial blending and then directed onto the apex of a conical splitter which collects the blended particles in a multiplicity of equal subvolumes. Thereafter the apparatus sequentially discharges the subvolumes for loading in a receptacle. A system for blending nuclear fuel particles and loading them into fuel rod molds is described in a preferred embodiment
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First-principles calculations of a half-metallic ferromagnet zinc blende Zn{sub 1−x}V{sub x}Te
Energy Technology Data Exchange (ETDEWEB)
El Amine Monir, M.; Baltache, H. [Laboratoire de Physique Quantique de la Modélisation Mathématique (LPQ3M), Université de Mascara, 29000 (Algeria); Khenata, R., E-mail: khenata_rabah@yahoo.fr [Laboratoire de Physique Quantique de la Modélisation Mathématique (LPQ3M), Université de Mascara, 29000 (Algeria); Murtaza, G. [Materials Modeling Laboratory, Department of Physics, Islamia College University, Peshawar (Pakistan); Azam, Sikander [New Technologies-Research Center, University of West Bohemia, Univerzitni 8, 306 14 Pilsen (Czech Republic); Bouhemadou, A. [Laboratory for Developing New Materials and their Characterization, Department of Physics, Faculty of Science, University Setif 1, 19000 Setif (Algeria); Al-Douri, Y. [Institute of Nano Electronic Engineering, University Malaysia Perlis, 01000 Kangar, Perlis (Malaysia); Bin Omran, S. [Department of Physics and Astronomy, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia); Ali, Roshan [Materials Modeling Lab, Department of Physics, Post Graduate Jahanzeb College, Swat (Pakistan)
2015-03-15
First-principles calculations have been used to study the structural, elastic, electronic, magnetic and thermal properties of zinc blende Zn{sub 1−x}V{sub x}Te for x=0, 0.25, 0.50, 0.75 and 1 using the full-potential linearized augmented plane wave method (FP-LAPW) based on spin-polarized density functional theory (DFT). The electronic exchange-correlation potential is approached using the spin generalized gradient approximation (spin-GGA). The structural properties of the Zn{sub 1−x}V{sub x}Te alloys (x=0, 0.25, 0.50, 0.75 and 1) are given for the lattice constants and the bulk moduli and their pressure derivatives. The elastic constants C{sub 11}, C{sub 12} and C{sub 44} are calculated using numerical first-principles calculations implemented in the WIEN2k package. An analysis of the band structures and the densities of states reveals that Zn{sub 0.50}V{sub 0.50}Te and Zn{sub 0.75}V{sub 0.25}Te exhibit a half-metallic character, while Zn{sub 0.25}V{sub 0.75}Te is nearly half-metallic. The band structure calculations are used to estimate the spin-polarized splitting energies Δ{sub x}(d) and Δ{sub x}(pd) produced by the V(3d)-doped and s(p)–d exchange constants N{sub 0α} (conduction band) and N{sub 0β} (valence band). The p–d hybridization reduces the magnetic moment of V from its atomic charge value of 3µ{sub B} and creates small local magnetic moments on the nonmagnetic Zn and Te sites. Finally, we present the thermal effect on the macroscopic properties of these alloys, such as the thermal expansion coefficient, heat capacity and Debye temperature, based on the quasi-harmonic Debye model. - Highlights: • Some physical properties of Vanadium doped ZnTe have been investigated. • Structural parameters for the parent compounds compare well with the available data. • The elastic and thermal properties are studied for the first time.
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Directory of Open Access Journals (Sweden)
Vanessa Rheinheimer
2016-08-01
Full Text Available This paper shows the microstructural differences and phase characterization of pure phases and hydrated products of the cubic and orthorhombic (Na-doped polymorphs of tricalcium aluminate (C3A, which are commonly found in traditional Portland cements. Pure, anhydrous samples were characterized using scanning transmission X-ray microscopy (STXM, X-ray photoelectron spectroscopy (XPS and X-ray diffraction (XRD and demonstrated differences in the chemical and mineralogical composition as well as the morphology on a micro/nano-scale. C3A/gypsum blends with mass ratios of 0.2 and 1.9 were hydrated using a water/C3A ratio of 1.2, and the products obtained after three days were assessed using STXM. The hydration process and subsequent formation of calcium sulfate in the C3A/gypsum systems were identified through the changes in the LIII edge fine structure for Calcium. The results also show greater Ca LII binding energies between hydrated samples with different gypsum contents. Conversely, the hydrated samples from the cubic and orthorhombic C3A at the same amount of gypsum exhibited strong morphological differences but similar chemical environments.
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Cubic interactions of Maxwell-like higher spins
Energy Technology Data Exchange (ETDEWEB)
Francia, Dario [Scuola Normale Superiore and INFN,Piazza dei Cavalieri, 7 I-56126 Pisa (Italy); Monaco, Gabriele Lo [Dipartimento di Fisica, Università di Pisa,Piazza Fibonacci, 3, I-56126, Pisa (Italy); Dipartimento di Fisica, Università di Milano-Bicocca,Piazza della Scienza 3, I-20126 Milano (Italy); Mkrtchyan, Karapet [Max Planck Institut für Gravitationsphysik,Am Mühlenberg 1, Potsdam 14476 (Germany)
2017-04-12
We study the cubic vertices for Maxwell-like higher-spins in flat and (A)dS background spaces of any dimension. Reducibility of their free spectra implies that a single cubic vertex involving any three fields subsumes a number of couplings among different particles of various spins. The resulting vertices do not involve traces of the fields and in this sense are simpler than their Fronsdal counterparts. We propose an extension of both the free theory and of its cubic deformation to a more general class of partially reducible systems, that one can obtain from the original theory upon imposing trace constraints of various orders. The key to our results is a version of the Noether procedure allowing to systematically account for the deformations of the transversality conditions to be imposed on the gauge parameters at the free level.
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Directory of Open Access Journals (Sweden)
Gary R. Nicklason
2015-07-01
Full Text Available We consider center conditions for plane polynomial systems of Abel type consisting of a linear center perturbed by the sum of 2 homogeneous polynomials of degrees n and 2n-1 where $n \\ge 2$. Using properties of Abel equations we obtain two general systems valid for arbitrary values on n. For the cubic n=2 systems we find several sets of new center conditions, some of which show that the results in a paper by Hill, Lloyd and Pearson which were conjectured to be complete are in fact not complete. We also present a particular system which appears to be a counterexample to a conjecture by Zoladek et al. regarding rational reversibility in cubic polynomial systems.
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Cubication of conservative nonlinear oscillators
International Nuclear Information System (INIS)
Belendez, Augusto; Alvarez, Mariela L; Fernandez, Elena; Pascual, Inmaculada
2009-01-01
A cubication procedure of the nonlinear differential equation for conservative nonlinear oscillators is analysed and discussed. This scheme is based on the Chebyshev series expansion of the restoring force, and this allows us to approximate the original nonlinear differential equation by a Duffing equation in which the coefficients for the linear and cubic terms depend on the initial amplitude, A, while in a Taylor expansion of the restoring force these coefficients are independent of A. The replacement of the original nonlinear equation by an approximate Duffing equation allows us to obtain an approximate frequency-amplitude relation as a function of the complete elliptic integral of the first kind. Some conservative nonlinear oscillators are analysed to illustrate the usefulness and effectiveness of this scheme.
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In Situ Fabrication of AlN Coating by Reactive Plasma Spraying of Al/AlN Powder
Directory of Open Access Journals (Sweden)
Mohammed Shahien
2011-10-01
Full Text Available Reactive plasma spraying is a promising technology for the in situ formation of aluminum nitride (AlN coatings. Recently, it became possible to fabricate cubic-AlN-(c-AlN based coatings through reactive plasma spraying of Al powder in an ambient atmosphere. However, it was difficult to fabricate a coating with high AlN content and suitable thickness due to the coalescence of the Al particles. In this study, the influence of using AlN additive (h-AlN to increase the AlN content of the coating and improve the reaction process was investigated. The simple mixing of Al and AlN powders was not suitable for fabricating AlN coatings through reactive plasma spraying. However, it was possible to prepare a homogenously mixed, agglomerated and dispersed Al/AlN mixture (which enabled in-flight interaction between the powder and the surrounding plasma by wet-mixing in a planetary mill. Increasing the AlN content in the mixture prevented coalescence and increased the nitride content gradually. Using 30 to 40 wt% AlN was sufficient to fabricate a thick (more than 200 µm AlN coating with high hardness (approximately 1000 Hv. The AlN additive prevented the coalescence of Al metal and enhanced post-deposition nitriding through N2 plasma irradiation by allowing the nitriding species in the plasma to impinge on a larger Al surface area. Using AlN as a feedstock additive was found to be a suitable method for fabricating AlN coatings by reactive plasma spraying. Moreover, the fabricated coatings consist of hexagonal (h-AlN, c-AlN (rock-salt and zinc-blend phases and certain oxides: aluminum oxynitride (Al5O6N, cubic sphalerite Al23O27N5 (ALON and Al2O3. The zinc-blend c-AlN and ALON phases were attributed to the transformation of the h-AlN feedstock during the reactive plasma spraying. Thus, the zinc-blend c
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Transdermal delivery of paeonol using cubic gel and microemulsion gel
Luo, Maofu; Shen, Qi; Chen, Jinjin
2011-01-01
Background The aim of this study was to develop new systems for transdermal delivery of paeonol, in particular microemulsion gel and cubic gel formulations. Methods Various microemulsion vehicles were prepared using isopropyl myristate as an oil phase, polyoxyethylated castor oil (Cremophor® EL) as a surfactant, and polyethylene glycol 400 as a cosurfactant. In the optimum microemulsion gel formulation, carbomer 940 was selected as the gel matrix, and consisted of 1% paeonol, 4% isopropyl myristate, 28% Cremophor EL/polyethylene glycol 400 (1:1), and 67% water. The cubic gel was prepared containing 3% paeonol, 30% water, and 67% glyceryl monooleate. Results A skin permeability test using excised rat skins indicated that both the cubic gel and microemulsion gel formulations had higher permeability than did the paeonol solution. An in vivo pharmacokinetic study done in rats showed that the relative bioavailability of the cubic gel and microemulsion gel was enhanced by about 1.51-fold and 1.28-fold, respectively, compared with orally administered paeonol suspension. Conclusion Both the cubic gel and microemulsion gel formulations are promising delivery systems to enhance the skin permeability of paeonol, in particular the cubic gel. PMID:21904450
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Directory of Open Access Journals (Sweden)
Mat Taib Norhidayah
2017-01-01
Full Text Available Diesel engine is known as the most efficient engine with high efficiency and power but always reported as high fuel emission. Malaysia National Automotive Policy (NAP was targeting to improve competitive regional focusing on green technology development in reducing the emission of the engine. Therefore, ethanol was introduced to reduce the emission of the engine and while increasing its performance, Palm methyl ester was introduced as blend enhancer to improve engine performance and improve diesel-ethanol blends stability. This paper aimed to study the characteristics of the blends and to prove the ability of palm-methyl-ester as co-solvent in ethanol-diesel blends. Stability and thermophysical test were carried out for different fuel compositions. The stability of diesel-ethanol blended was proved to be improved with the addition of PME at the longer period and the stability of the blends changed depending on temperature and ethanol content. Density and viscosity of diesel-ethanol-PME blends also give higher result than diesel-ethanol blends and it's proved that PME is able to increase density and viscosity of blends. Besides, heating value of the blends also increases with the increasing PME in diesel-ethanol blends.
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Nonlinear dynamics of quadratically cubic systems
International Nuclear Information System (INIS)
Rudenko, O V
2013-01-01
We propose a modified form of the well-known nonlinear dynamic equations with quadratic relations used to model a cubic nonlinearity. We show that such quadratically cubic equations sometimes allow exact solutions and sometimes make the original problem easier to analyze qualitatively. Occasionally, exact solutions provide a useful tool for studying new phenomena. Examples considered include nonlinear ordinary differential equations and Hopf, Burgers, Korteweg–de Vries, and nonlinear Schrödinger partial differential equations. Some problems are solved exactly in the space–time and spectral representations. Unsolved problems potentially solvable by the proposed approach are listed. (methodological notes)
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Directory of Open Access Journals (Sweden)
Akbar Badii
2012-01-01
Full Text Available After iron deficiency, zinc deficiency is the major micronutrient deficiency in developing countries, and staple food fortification is an effective strategy to prevent and improve it among at-risk-populations. No action has been taken to reduce zinc deficiency via flour fortification so far in Iran, and little is known about the influence of zinc fortification of flour on serum zinc and the iron status, and also about the optimum and effective amount of zinc compound that is used in food fortification. The objective of this study is to evaluate the influence of consuming zinc-fortified breads on the zinc and iron status in the blood serum. In this study, three types of bread were prepared from non-fortified and fortified flours, with 50 and 100 ppm elemental zinc in the form of sulfate. Eighty zinc-deficient women aged 19 to 49 years were randomly assigned to three groups; The volunteers received, daily, (1 a non-fortified bread, (2 a high-zinc bread, and (3 a low-zinc bread for one month. Serum zinc and iron were measured by Atomic Absorption before and after the study. Results showed a significant increase in serum zinc and iron levels in all groups (p 0.05. Absorption of zinc and iron in the group that consumed high-zinc bread was significantly greater than that in the group that received low-zinc bread (p < 0.01. It was concluded that fortification of flour with 50-100 ppm zinc was an effective way to achieve adequate zinc intake and absorption in zinc-deficient people. It also appeared that consuming zinc-fortified bread improved iron absorption.
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International Nuclear Information System (INIS)
Prudnikau, Anatol; Artemyev, Mikhail; Molinari, Michael; Troyon, Michel; Sukhanova, Alyona; Nabiev, Igor; Baranov, Alexandr V.; Cherevkov, Sergey A.; Fedorov, Anatoly V.
2012-01-01
Highlights: ► We studied cadmium-by-mercury chemical substitution in CdSe nanocrystals. ► Zinc blende CdSe quantum dots can be easily converted to isostructural Cd x Hg 1−x Se. ► Wurtzite CdSe QDs require longer time to convert to a zinc blende Cd x Hg 1−x Se. ► Wurtzite CdSe nanorods transform to nanoheterogeneous luminescent Cd x Hg 1−x Se rods. - Abstract: The chemical substitution of cadmium by mercury in colloidal CdSe quantum dots (QDs) and nanorods has been examined by absorption, photoluminescence and Raman spectroscopy. The crystalline structure of original CdSe QDs used for Cd/Hg substitution (zinc blende versus wurtzite) shows a strong impact on the optical and structural properties of resultant Cd x Hg 1−x Se nanocrystals. Substitution of Cd by Hg in isostructural zinc blende CdSe QDs converts them to ternary Cd x Hg 1−x Se zinc blende nanocrystals with significant NIR emission. Whereas, the wurtzite CdSe QDs transformed first to ternary nanocrystals with almost no emission followed by slow structural reorganization to a NIR-emitting zinc blende Cd x Hg 1−x Se QDs. CdSe nanorods with intrinsic wurtzite structure show unexpectedly intense NIR emission even at early Cd/Hg substitution stage with PL active zinc blende Cd x Hg 1−x Se regions.
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Energy Technology Data Exchange (ETDEWEB)
Zhou, Zhaobo [Key Laboratory of Advanced Materials of Yunnan Province & Key Laboratory of Advanced Materials of Non-Ferrous and Precious Rare Metals Ministry of Education, Kunming University of Science and Technology, Kunming 650093 (China); Zhou, Xiaolong, E-mail: kmzxlong@163.com [Key Laboratory of Advanced Materials of Yunnan Province & Key Laboratory of Advanced Materials of Non-Ferrous and Precious Rare Metals Ministry of Education, Kunming University of Science and Technology, Kunming 650093 (China); Zhang, Kunhua [State Key Laboratory of Rare Precious Metals Comprehensive Utilization of New Technologies, Kunming Institute of Precious Metals, Kunming 650106 (China)
2016-12-15
First-principle calculations were performed to investigate the structural, phase stability, electronic, elastic properties and hardness of monoclinic structure IrN{sub 2} (m-IrN{sub 2}), orthorhombic structure IrN{sub 2} (o-IrN{sub 2}) and zinc blende structure IrN (ZB IrN). The results show us that only m-IrN{sub 2} is both thermodynamic and dynamic stability. The calculated band structure and density of states (DOS) curves indicate that o-IrN{sub 2} and ZB Ir-N compounds we calculated have metallic behavior while m-IrN{sub 2} has a small band gap of ~0.3 eV, and exist a common hybridization between Ir-5d and N-2p states, which forming covalent bonding between Ir and N atoms. The difference charge density reveals the electron transfer from Ir atom to N atom for three Ir-N compounds, which forming strong directional covalent bonds. Notable, a strong N-N bond appeared in m-IrN{sub 2} and o-IrN{sub 2}. The ratio of bulk to shear modulus (B/G) indicate that three Ir-N compounds we calculated are ductile, and ZB IrN possesses a better ductility than two types IrN{sub 2}. m-IrN{sub 2} has highest Debye temperature (736 K), illustrating it possesses strongest covalent bonding. The hardness of three Ir-N compounds were also calculated, and the results reveal that m-IrN{sub 2} (18.23 GPa) and o-IrN{sub 2} (18.02 GPa) are ultraincompressible while ZB IrN has a negative value, which may be attributed to phase transition at ca. 1.98 GPa.
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III-nitrides on oxygen- and zinc-face ZnO substrates
International Nuclear Information System (INIS)
Namkoong, Gon; Burnham, Shawn; Lee, Kyoung-Keun; Trybus, Elaissa; Doolittle, W. Alan; Losurdo, Maria; Capezzuto, Pio; Bruno, Giovanni; Nemeth, Bill; Nause, Jeff
2005-01-01
The characteristics of III-nitrides grown on zinc- and oxygen-face ZnO by plasma-assisted molecular beam epitaxy were investigated. The reflection high-energy electron diffraction pattern indicates formation of a cubic phase at the interface between III-nitride and both Zn- and O-face ZnO. The polarity indicates that Zn-face ZnO leads to a single polarity, while O-face ZnO forms mixed polarity of III-nitrides. Furthermore, by using a vicinal ZnO substrate, the terrace-step growth of GaN was realized with a reduction by two orders of magnitude in the dislocation-related etch pit density to ∼10 8 cm -2 , while a dislocation density of ∼10 10 cm -2 was obtained on the on-axis ZnO substrates
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On Application of Non-cubic EoS to Compositional Reservoir Simulation
DEFF Research Database (Denmark)
Yan, Wei; Michelsen, Michael Locht; Stenby, Erling Halfdan
Compositional reservoir simulation uses almost exclusively cubic equations of state (EoS) such as the SRK EoS and the PR EoS. This is in contrast with process simulation in the downstream industry where more recent and advanced thermodynamic models are quickly adopted. Many of these models are non-cubic...... EoS, such as the PC-SAFT EoS. A major reason for the use of the conventional cubic EoS in reservoir simulation is the concern over computation time. Flash computation is the most time consuming part in compositional reservoir simulation, and the extra complexity of the non-cubic EoS may significantly...... increase the time consumption. In addition to this, the non-cubic EoS also needs a C7+ characterization. The main advantage of the non-cubic EoS is that it provides for a more accurate descrition of fluid properties, and it is therefore of interest to investigate the computational aspects of using...
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Purely cubic action for string field theory
Horowitz, G. T.; Lykken, J.; Rohm, R.; Strominger, A.
1986-01-01
It is shown that Witten's (1986) open-bosonic-string field-theory action and a closed-string analog can be written as a purely cubic interaction term. The conventional form of the action arises by expansion around particular solutions of the classical equations of motion. The explicit background dependence of the conventional action via the Becchi-Rouet-Stora-Tyutin operator is eliminated in the cubic formulation. A closed-form expression is found for the full nonlinear gauge-transformation law.
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Radiation effect on PVC/ENR blends
International Nuclear Information System (INIS)
Chantara Thevy Ratnam; Khairul Zaman Mohd Dahlan
1997-01-01
The effect of irradiation on the physical properties of Polyvinyl Chloride / Epoxidised Natural Rubber Blends (PVC/ENR blends) were investigated. The enhancement in tensile strength, elongation at break, hardness and aging properties of the blends have confirmed the positive effect of irradiation on the blends. It is evident from gel fraction and infra red spectroscopic studies that the blends of PVC and ENR cross-linked upon irradiation. The results also revealed that at any blend composition, the enhancement in properties depend on irradiation dose which controls the degree of radiation induced cross-linking. In an attempt to maximize the constructive effect of irradiation, the influence of various additives such as stabilizers, radiation sensitizers, fillers and processing aids on the blend properties were studied. The changes in blend properties upon irradiation with the presents of above additives were also presented in this paper
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International Nuclear Information System (INIS)
Chen, Dazheng; Zhang, Chunfu; Wang, Zhizhe; Zhang, Jincheng; Tang, Shi; Wei, Wei; Sun, Li; Hao, Yue
2014-01-01
Indium-tin-oxide (ITO) free inverted organic solar cells (IOSCs) based on aluminum-doped zinc oxide (AZO) cathode, low-temperature aqueous solution processed zinc oxide (ZnO) electron extraction layer, and poly(3-hexylthiophene-2, 5-diyl):[6, 6]-phenyl C 61 butyric acid methyl ester blend were realized in this work. The resulted IOSC with ZnO annealed at 150 °C shows the superior power conversion efficiency (PCE) of 3.01%, if decreasing the ZnO annealing temperature to 100 °C, the obtained IOSC also shows a PCE of 2.76%, and no light soaking issue is observed. It is found that this ZnO film not only acts as an effective buffer layer but also slightly improves the optical transmittance of AZO substrates. Further, despite the relatively inferior air-stability, these un-encapsulated AZO/ZnO IOSCs show comparable PCEs to the referenced ITO/ZnO IOSCs, which demonstrates that the AZO cathode is a potential alternative to ITO in IOSCs. Meanwhile, this simple ZnO process is compatible with large area deposition and plastic substrates, and is promising to be widely used in IOSCs and other relative fields.
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Cooper, J.F.
1996-11-26
Uniform zinc pellets are formed for use in batteries having a stationary or moving slurry zinc particle electrode. The process involves the cathodic deposition of zinc in a finely divided morphology from battery reaction product onto a non-adhering electrode substrate. The mossy zinc is removed from the electrode substrate by the action of gravity, entrainment in a flowing electrolyte, or by mechanical action. The finely divided zinc particles are collected and pressed into pellets by a mechanical device such as an extruder, a roller and chopper, or a punch and die. The pure zinc pellets are returned to the zinc battery in a pumped slurry and have uniform size, density and reactivity. Applications include zinc-air fuel batteries, zinc-ferricyanide storage batteries, and zinc-nickel-oxide secondary batteries. 6 figs.
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Energy Technology Data Exchange (ETDEWEB)
Adams, R.G.; Gibb, W.H.; Majid, K.A. [Power Technology (United Kingdom)
1999-07-01
Successful coal blending requires finding a careful balance between fuel costs and plant performance. A recent study of a Malaysian power plant shows how the utility (Tenaga Nasional Berhad (TNB)) could reduce fuel costs while avoiding boiler operating problems normally associated with firing low-grade coals. TNB`s Kaper 2220 MW power station in Selangor needed an improved method of coal blending for two new 500 MW units and for two existing 300 MW units. UK`s Power Technology was commissioned to identify what coal blends the boiler could tolerate. A Coal Quality Impact Model (CQIM) analysis of the effect of different coals and coal blends on combustion performance and economics, and a performance analysis of coal yard handling facility was made to determine whether the accuracy of the required blend could be achieved (using a Coal Handling Simulation, CHAS, software package). The CQIM study showed that the proportion of cheaper coals could be increased from 20% to 50% provided each shipment was adequately sampled. The CHAS study showed that use of a flat back reclaimer or modifications to the dry coal stove would allow accurate blending. 5 figs., 1 tab.
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Cysteine-rich intestinal protein binds zinc during transmucosal zinc transport
International Nuclear Information System (INIS)
Hempe, J.M.; Cousins, R.J.
1991-01-01
The mechanism of zinc absorption has not been delineated, but kinetic studies show that both passive and carrier-mediated processes are involved. The authors have identified a low molecular mass zinc-binding protein in the soluble fraction of rat intestinal mucosa that could function as an intracellular zinc carrier. The protein was not detected in liver or pancreas, suggesting a role specific to the intestine. The protein binds zinc during transmucosal zinc transport and shows signs of saturation at higher luminal zinc concentrations, characteristics consistent with a role in carrier-mediated zinc absorption. Microsequence analysis of the protein purified by gel-filtration HPCL and SDS/PAGE showed complete identity within the first 41 N-terminal amino acids with the deduced protein sequence of cysteine-rich intestinal protein. These investigators showed that the gene for this protein is developmentally regulated in neonates during the suckling period, conserved in many vertebrate species, and predominantly expressed in the small intestine. Cysteine-rich intestinal protein contains a recently identified conserved sequence of histidine and cysteine residues, the LIM motif, which our results suggest confers metal-binding properties that are important for zinc transport and/or functions of this micronutrient
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Plastic fluctuations in empty crystals formed by cubic wireframe particles
McBride, John M.; Avendaño, Carlos
2018-05-01
We present a computer simulation study of the phase behavior of colloidal hard cubic frames, i.e., particles with nonconvex cubic wireframe geometry interacting purely by excluded volume. Despite the propensity of cubic wireframe particles to form cubic phases akin to their convex counterparts, these particles exhibit unusual plastic fluctuations in which a random and dynamic fraction of particles rotate around their lattice positions in the crystal lattice while the remainder of the particles remains fully ordered. We argue that this unexpected effect stems from the nonconvex geometry of the particles in which the faces of a particle can be penetrated by the vertices of the nearest neighbors even at high number densities.
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Eliminating cubic terms in the pseudopotential lattice Boltzmann model for multiphase flow
Huang, Rongzong; Wu, Huiying; Adams, Nikolaus A.
2018-05-01
It is well recognized that there exist additional cubic terms of velocity in the lattice Boltzmann (LB) model based on the standard lattice. In this work, elimination of these cubic terms in the pseudopotential LB model for multiphase flow is investigated, where the force term and density gradient are considered. By retaining high-order (≥3 ) Hermite terms in the equilibrium distribution function and the discrete force term, as well as introducing correction terms in the LB equation, the additional cubic terms of velocity are entirely eliminated. With this technique, the computational simplicity of the pseudopotential LB model is well maintained. Numerical tests, including stationary and moving flat and circular interface problems, are carried out to show the effects of such cubic terms on the simulation of multiphase flow. It is found that the elimination of additional cubic terms is beneficial to reduce the numerical error, especially when the velocity is relatively large. Numerical results also suggest that these cubic terms mainly take effect in the interfacial region and that the density-gradient-related cubic terms are more important than the other cubic terms for multiphase flow.
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Maywald, Martina; Wessels, Inga; Rink, Lothar
2017-10-24
Zinc homeostasis is crucial for an adequate function of the immune system. Zinc deficiency as well as zinc excess result in severe disturbances in immune cell numbers and activities, which can result in increased susceptibility to infections and development of especially inflammatory diseases. This review focuses on the role of zinc in regulating intracellular signaling pathways in innate as well as adaptive immune cells. Main underlying molecular mechanisms and targets affected by altered zinc homeostasis, including kinases, caspases, phosphatases, and phosphodiesterases, will be highlighted in this article. In addition, the interplay of zinc homeostasis and the redox metabolism in affecting intracellular signaling will be emphasized. Key signaling pathways will be described in detail for the different cell types of the immune system. In this, effects of fast zinc flux, taking place within a few seconds to minutes will be distinguish from slower types of zinc signals, also designated as "zinc waves", and late homeostatic zinc signals regarding prolonged changes in intracellular zinc.
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Synthesis, field emission properties and optical properties of ZnSe nanoflowers
Energy Technology Data Exchange (ETDEWEB)
Xue, S.L., E-mail: slxue@dhu.edu.cn [Department of Applied Physics, College of Science, Donghua University, Shanghai 201620 (China); Wu, S.X.; Zeng, Q.Z.; Xie, P.; Gan, K.X.; Wei, J.; Bu, S.Y.; Ye, X.N.; Xie, L. [Department of Applied Physics, College of Science, Donghua University, Shanghai 201620 (China); Zou, R.J. [State Key Laboratory for Modification and Chemical Fibers and Polymer Materials, Donghua University, Shanghai 201620 (China); Zhang, C.M.; Zhu, P.F. [Department of Physics, School of Fundamental Studies, Shanghai University of Engineering Science, Shanghai 201620 (China)
2016-03-01
Graphical abstract: Unique ZnSe nanoflowers have been successfully synthesized by reaction of Se powder with Zn substrates. They are characterized by XRD, SEM, TEM, XPS, EDS and Raman spectroscopy and were single crystals with cubic zinc blende (ZB) structure. They also have excellent field emission properties and optical properties. - Highlights: • Novel ZnSe nanoflowers are grown on Zn foils. • ZnSe nanoflowers are characterized by XRD, SEM, TEM, XPS and Raman spectra. • ZnSe nanoflowers on Zn foils as cathodes possess good FE properties. - Abstract: ZnSe nanoflowers have been synthesized by reaction of Se powder with Zn substrates at low temperature. The as-prepared ZnSe nanoflowers were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), X-ray energy dispersive spectroscope (EDS) and Raman spectroscopy measurements. It was found that the morphologies of the as-prepared samples highly depended on reaction time. ZnSe nanoclusters and nanoflowers formed at 573 K when the reaction time was 20 and 60 min, respectively. The as-prepared ZnSe nanoflowers were composed of radically aligned ZnSe nanorods with smooth surfaces. The results of XRD, XPS, EDS, TEM and Raman showed that the as-prepared ZnSe nanocrystals were single crystals with cubic zinc blende (ZB) structure. The formation mechanism of the as-prepared ZnSe nanoflowers was also discussed. In addition, the as-prepared ZnSe nanoflowers had excellent electron emission properties. The turn-on field of the as-prepared ZnSe nanoflowers was 3.5 V/μm and the enhancement factor was 3499. The optical properties of the as-prepared ZnSe nanoflowers were also investigated. The results demonstrated that the as-prepared ZnSe nanoflowers were potential candidates for optoelectronic devices.
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Zinc in Cellular Regulation: The Nature and Significance of "Zinc Signals".
Maret, Wolfgang
2017-10-31
In the last decade, we witnessed discoveries that established Zn 2+ as a second major signalling metal ion in the transmission of information within cells and in communication between cells. Together with Ca 2+ and Mg 2+ , Zn 2+ covers biological regulation with redox-inert metal ions over many orders of magnitude in concentrations. The regulatory functions of zinc ions, together with their functions as a cofactor in about three thousand zinc metalloproteins, impact virtually all aspects of cell biology. This article attempts to define the regulatory functions of zinc ions, and focuses on the nature of zinc signals and zinc signalling in pathways where zinc ions are either extracellular stimuli or intracellular messengers. These pathways interact with Ca 2+ , redox, and phosphorylation signalling. The regulatory functions of zinc require a complex system of precise homeostatic control for transients, subcellular distribution and traffic, organellar homeostasis, and vesicular storage and exocytosis of zinc ions.
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Badii, Akbar; Nekouei, Niloufar; Fazilati, Mohammad; Shahedi, Mohammad; Badiei, Sajad
2012-03-01
After iron deficiency, zinc deficiency is the major micronutrient deficiency in developing countries, and staple food fortification is an effective strategy to prevent and improve it among at-risk-populations. No action has been taken to reduce zinc deficiency via flour fortification so far in Iran, and little is known about the influence of zinc fortification of flour on serum zinc and the iron status, and also about the optimum and effective amount of zinc compound that is used in food fortification. The objective of this study is to evaluate the influence of consuming zinc-fortified breads on the zinc and iron status in the blood serum. In this study, three types of bread were prepared from non-fortified and fortified flours, with 50 and 100 ppm elemental zinc in the form of sulfate. Eighty zinc-deficient women aged 19 to 49 years were randomly assigned to three groups; The volunteers received, daily, (1) a non-fortified bread, (2) a high-zinc bread, and (3) a low-zinc bread for one month. Serum zinc and iron were measured by Atomic Absorption before and after the study. Results showed a significant increase in serum zinc and iron levels in all groups (p 0.05). Absorption of zinc and iron in the group that consumed high-zinc bread was significantly greater than that in the group that received low-zinc bread (p bread improved iron absorption.
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Kinks in systems with cubic and quartic anharmonicity
International Nuclear Information System (INIS)
Kashcheev, V.N.
1988-01-01
For a classical system of interacting particles with on-site cubic or quartic anharmonicity explicit analytic solutions of the d'Alembert equation are obtained in the form of kinks in the presence of dissipation (viscous or Rayleigh) and a constant force. These kinks will be asymptotically stable in the case of quartic anharmonicity and unstable in the case cubic anharmonicity
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Decentralized Blended Acquisition
Berkhout, A.J.
2013-01-01
The concept of blending and deblending is reviewed, making use of traditional and dispersed source arrays. The network concept of distributed blended acquisition is introduced. A million-trace robot system is proposed, illustrating that decentralization may bring about a revolution in the way we
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... Some early research suggests that zinc supplementation increases sperm count, testosterone levels, and pregnancy rates in infertile men with low testosterone levels. Other research suggests that taking zinc can improve sperm shape in men with moderate enlargement of a ...
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Blended Learning: enabling Higher Education Reform
Directory of Open Access Journals (Sweden)
Kathleen Matheos
2018-01-01
Full Text Available Blended learning research and practice have been areas of growth for two decades in Canada, with over 95% of Canadian higher education institutions involved in some form of blended learning. Despite strong evidence based research and practice blended learning, for the most part, has remained at sidelined in Canadian universities. The article argues the need for blended learning to situate itself within the timely and crucial Higher Education Reform (HER agenda. By aligning the affordances of blended learning with the components of HER, blended learning can clearly serve as an enabler for HER.
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Relationship between maternal serum zinc, cord blood zinc and ...
African Journals Online (AJOL)
Background: Adequate in utero supply of zinc is essential for optimal fetal growth because of the role of zinc in cellular division, growth and differentiation. Low maternal serum zinc has been reported to be associated with low birth weight and the later is associated with increased morbidity and mortality in newborns.
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International Nuclear Information System (INIS)
Garcia, Susan E.; Giannelli, Joseph F.; Jarvis, Alfred J.
2014-01-01
Boiling Water Reactors (BWRs) have been injecting zinc into the primary coolant via the reactor feedwater system for over 25 years for the purpose of controlling primary system radiation fields. The BWR zinc injection process has evolved since the initial application at the Hope Creek Nuclear Station in 1986. Key transitions were from the original natural zinc oxide (NZO) to depleted zinc oxide (DZO), and from active zinc injection of a powdered zinc oxide slurry (pumped systems) to passive injection systems (zinc pellet beds). Zinc addition has continued through various chemistry regimes changes, from normal water chemistry (NWC) to hydrogen water chemistry (HWC) and HWC with noble metals (NobleChem™) for mitigation of intergranular stress corrosion cracking (IGSCC) of reactor internals and primary system piping. While past reports published by the Electric Power Research Institute (EPRI) document specific industry experience related to these topics, the Zinc Sourcebook was prepared to consolidate all of the experience gained over the past 25 years. The Zinc Sourcebook will benefit experienced BWR Chemistry, Operations, Radiation Protection and Engineering personnel as well as new people entering the nuclear power industry. While all North American BWRs implement feedwater zinc injection, a number of other BWRs do not inject zinc. This Sourcebook will also be a valuable resource to plants considering the benefits of zinc addition process implementation, and to gain insights on industry experience related to zinc process control and best practices. This paper presents some of the highlights from the Sourcebook. (author)
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Zinc at glutamatergic synapses.
Paoletti, P; Vergnano, A M; Barbour, B; Casado, M
2009-01-12
It has long been known that the mammalian forebrain contains a subset of glutamatergic neurons that sequester zinc in their synaptic vesicles. This zinc may be released into the synaptic cleft upon neuronal activity. Extracellular zinc has the potential to interact with and modulate many different synaptic targets, including glutamate receptors and transporters. Among these targets, NMDA receptors appear particularly interesting because certain NMDA receptor subtypes (those containing the NR2A subunit) contain allosteric sites exquisitely sensitive to extracellular zinc. The existence of these high-affinity zinc binding sites raises the possibility that zinc may act both in a phasic and tonic mode. Changes in zinc concentration and subcellular zinc distribution have also been described in several pathological conditions linked to glutamatergic transmission dysfunctions. However, despite intense investigation, the functional significance of vesicular zinc remains largely a mystery. In this review, we present the anatomy and the physiology of the glutamatergic zinc-containing synapse. Particular emphasis is put on the molecular and cellular mechanisms underlying the putative roles of zinc as a messenger involved in excitatory synaptic transmission and plasticity. We also highlight the many controversial issues and unanswered questions. Finally, we present and compare two widely used zinc chelators, CaEDTA and tricine, and show why tricine should be preferred to CaEDTA when studying fast transient zinc elevations as may occur during synaptic activity.
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2010-01-01
... 7 Agriculture 8 2010-01-01 2010-01-01 false Blend. 989.16 Section 989.16 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and... CALIFORNIA Order Regulating Handling Definitions § 989.16 Blend. Blend means to mix or commingle raisins. ...
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Tracing of Zinc Nanocrystals in the Anterior Pituitary of Zinc-Deficient Wistar Rats.
Kuldeep, Anjana; Nair, Neena; Bedwal, Ranveer Singh
2017-06-01
The aim of this study was to trace zinc nanocrystals in the anterior pituitary of zinc-deficient Wistar rats by using autometallographic technique. Male Wistar rats (30-40 days of age, pre-pubertal period) of 40-50 g body weight were divided into the following: the ZC (zinc control) group-fed with 100 ppm zinc in diet, the ZD (zinc-deficient) group-fed with zinc-deficient (1.00 ppm) diet and the PF (pair-fed) group-received 100 ppm zinc in diet. The experiments were set for 2 and 4 weeks. Pituitary was removed and processed for the autometallographic technique. The control and pair-fed groups retained their normal morphological features. However, male Wistar rats fed on zinc-deficient diet for 2 and 4 weeks displayed a wide range of symptoms such as significant (P zinc nanocrystals in the nuclei. The present findings suggest that the dietary zinc deficiency causes decreased intensity of zinc nanocrystals localization and their distribution in the pituitary thereby contributing to the dysfunction of the pituitary of the male Wistar rats. The severity of zinc deficiency symptoms progressed after the second week of the experiment. Decreased intensity of zinc nanocrystals attenuates the pituitary function which would exert its affect on other endocrine organs impairing their functions indicating that the metabolic regulation of pituitary is mediated to a certain extent by zinc and/or hypothalamus-hypophysial system which also reflects its essentiality during the period of growth.
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Effect of Blending on the Composition and Acceptability of Blends of ...
African Journals Online (AJOL)
However the blend was found deficient in lysine, leucine, iso-leucine and phenylalanine when compared with the FAO recommendations for infants. Increased levels of pigeon pea in the blend also resulted in significant increases in potassium, phosphorus, sodium, magnesium and calcium. Similarly, increased levels of ...
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Deformation of the cubic open string field theory
Energy Technology Data Exchange (ETDEWEB)
Lee, Taejin, E-mail: taejin@kangwon.ac.kr
2017-05-10
We study a consistent deformation of the cubic open bosonic string theory in such a way that the non-planar world sheet diagrams of the perturbative string theory are mapped onto their equivalent planar diagrams of the light-cone string field theory with some length parameters fixed. An explicit evaluation of the cubic string vertex in the zero-slope limit yields the correct relationship between the string coupling constant and the Yang–Mills coupling constant. The deformed cubic open string field theory is shown to produce the non-Abelian Yang–Mills action in the zero-slope limit if it is defined on multiple D-branes. Applying the consistent deformation systematically to multi-string world sheet diagrams, we may be able to calculate scattering amplitudes with an arbitrary number of external open strings.
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Deformation of the cubic open string field theory
International Nuclear Information System (INIS)
Lee, Taejin
2017-01-01
We study a consistent deformation of the cubic open bosonic string theory in such a way that the non-planar world sheet diagrams of the perturbative string theory are mapped onto their equivalent planar diagrams of the light-cone string field theory with some length parameters fixed. An explicit evaluation of the cubic string vertex in the zero-slope limit yields the correct relationship between the string coupling constant and the Yang–Mills coupling constant. The deformed cubic open string field theory is shown to produce the non-Abelian Yang–Mills action in the zero-slope limit if it is defined on multiple D-branes. Applying the consistent deformation systematically to multi-string world sheet diagrams, we may be able to calculate scattering amplitudes with an arbitrary number of external open strings.
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Deformation of the cubic open string field theory
Directory of Open Access Journals (Sweden)
Taejin Lee
2017-05-01
Full Text Available We study a consistent deformation of the cubic open bosonic string theory in such a way that the non-planar world sheet diagrams of the perturbative string theory are mapped onto their equivalent planar diagrams of the light-cone string field theory with some length parameters fixed. An explicit evaluation of the cubic string vertex in the zero-slope limit yields the correct relationship between the string coupling constant and the Yang–Mills coupling constant. The deformed cubic open string field theory is shown to produce the non-Abelian Yang–Mills action in the zero-slope limit if it is defined on multiple D-branes. Applying the consistent deformation systematically to multi-string world sheet diagrams, we may be able to calculate scattering amplitudes with an arbitrary number of external open strings.
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Energy Technology Data Exchange (ETDEWEB)
König, Dirk, E-mail: dirk.koenig@unsw.edu.au [Integrated Materials Design Centre (IMDC) and School of Photovoltaic and Renewable Energy Engineering (SPREE), University of New South Wales, Sydney (Australia)
2016-08-15
Semiconductor nanocrystals (NCs) experience stress and charge transfer by embedding materials or ligands and impurity atoms. In return, the environment of NCs experiences a NC stress response which may lead to matrix deformation and propagated strain. Up to now, there is no universal gauge to evaluate the stress impact on NCs and their response as a function of NC size d{sub NC}. I deduce geometrical number series as analytical tools to obtain the number of NC atoms N{sub NC}(d{sub NC}[i]), bonds between NC atoms N{sub bnd}(d{sub NC}[i]) and interface bonds N{sub IF}(d{sub NC}[i]) for seven high symmetry zinc-blende (zb) NCs with low-index faceting: {001} cubes, {111} octahedra, {110} dodecahedra, {001}-{111} pyramids, {111} tetrahedra, {111}-{001} quatrodecahedra and {001}-{111} quadrodecahedra. The fundamental insights into NC structures revealed here allow for major advancements in data interpretation and understanding of zb- and diamond-lattice based nanomaterials. The analytical number series can serve as a standard procedure for stress evaluation in solid state spectroscopy due to their deterministic nature, easy use and general applicability over a wide range of spectroscopy methods as well as NC sizes, forms and materials.
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Morphology stabilization of heterogeneous blends
International Nuclear Information System (INIS)
1980-01-01
A heterogeneous elastomer blend is described, consisting of at least two elastomer components which are cross-linkable by irradiation and having a stabilized morphology formed by subjecting the blend to high energy radiation to a point from below to slightly above the gel dose of the blend. (author)
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Locally restricted blending of Blobtrees
Groot, de Erwin; Wyvill, B.; Wetering, van de H.M.M.
2009-01-01
Blobtrees are volume representations particularly useful for models which require smooth blending. When blending is applied to two or more Blobtree models, extra volume will be created in between the two surfaces to form a smooth connection. Although it is easy to apply blending, it is hard to
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Performance of Blended Learning in University Teaching:
Directory of Open Access Journals (Sweden)
Michael Reiss
2010-07-01
Full Text Available Blended learning as a combination of classroom teaching and e-learning has become a widely represented standard in employee and management development of companies. The exploratory survey “Blended Learning@University” conducted in 2008 investigated the integration of blended learning in higher education. The results of the survey show that the majority of participating academic teachers use blended learning in single courses, but not as a program of study and thus do not exploit the core performance potential of blended learning. According to the study, the main driver of blended learning performance is its embeddedness in higher education. Integrated blended programs of study deliver the best results. In blended learning, learning infrastructure (in terms of software, culture, skills, funding, content providing, etc. does not play the role of a performance driver but serves as an enabler for blended learning.
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Interaction of dispersed cubic phases with blood components
DEFF Research Database (Denmark)
Bode, J C; Kuntsche, Judith; Funari, S S
2013-01-01
The interaction of aqueous nanoparticle dispersions, e.g. based on monoolein/poloxamer 407, with blood components is an important topic concerning especially the parenteral way of administration. Therefore, the influence of human and porcine plasma on dispersed cubic phases was investigated. Part...... activity of cubic phases based on monoolein and poloxamer 188, on soy phosphatidylcholine, glycerol dioleate and polysorbate 80 or the parenteral fat emulsion Lipofundin MCT 20%....
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Directory of Open Access Journals (Sweden)
Ľuboš Harangozo
2012-02-01
Full Text Available The yeast Saccharomyces cerevisiae is the best known microorganism and therefore widely used in many branches of industry. This study aims to investigate the accumulation of three inorganic zinc salts. Our research presents the ability of this yeast to absorb zinc from liquid medium and such enriched biomass use as a potential source of microelements in animal and/or human nutrition. It was found that the addition of different zinc forms, i.e. zinc nitrate, zinc sulphate and zinc chloride in fixed concentrations of 0, 25, 50 and 100 mg.100 ml-1 did not affect the amount of dry yeast biomass yielded, i.e. 1.0 – 1.2 g of yeast cells from 100 ml of cultivation medium, while higher presence of zinc solutions caused significantly lower yield of yeast biomass. The highest amount of zinc in yeast cells was achieved when added in the form of zinc nitrate in concentration of 200 mg.100 ml-1 YPD medium. The increment of intracellular zinc was up to 18.5 mg.g-1 of yeast biomass.
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The study and microstructure analysis of zinc and zinc oxide
Czech Academy of Sciences Publication Activity Database
Luptáková, Natália; Pešlová, F.; Kliber, J.
2015-01-01
Roč. 54, č. 1 (2015), s. 43-46 ISSN 0543-5846 Grant - others:KEGA(SK) KEGA 007 TnUAD-4/2013 Institutional support: RVO:68081723 Keywords : zinc * production of zinc oxide * microstructure * chemical composition * zinc slag Subject RIV: JG - Metal lurgy Impact factor: 0.959, year: 2014
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Zinc Biochemistry: From a Single Zinc Enzyme to a Key Element of Life12
Maret, Wolfgang
2013-01-01
The nutritional essentiality of zinc for the growth of living organisms had been recognized long before zinc biochemistry began with the discovery of zinc in carbonic anhydrase in 1939. Painstaking analytical work then demonstrated the presence of zinc as a catalytic and structural cofactor in a few hundred enzymes. In the 1980s, the field again gained momentum with the new principle of “zinc finger” proteins, in which zinc has structural functions in domains that interact with other biomolecules. Advances in structural biology and a rapid increase in the availability of gene/protein databases now made it possible to predict zinc-binding sites from metal-binding motifs detected in sequences. This procedure resulted in the definition of zinc proteomes and the remarkable estimate that the human genome encodes ∼3000 zinc proteins. More recent developments focus on the regulatory functions of zinc(II) ions in intra- and intercellular information transfer and have tantalizing implications for yet additional functions of zinc in signal transduction and cellular control. At least three dozen proteins homeostatically control the vesicular storage and subcellular distribution of zinc and the concentrations of zinc(II) ions. Novel principles emerge from quantitative investigations on how strongly zinc interacts with proteins and how it is buffered to control the remarkably low cellular and subcellular concentrations of free zinc(II) ions. It is fair to conclude that the impact of zinc for health and disease will be at least as far-reaching as that of iron. PMID:23319127
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International Nuclear Information System (INIS)
Pally, Monique; Foulquier, Luc
1976-07-01
Zinc uptake was studied in eels in fresh water, using stable zinc, a zinc-cadmium mixture, and zinc 65 in the presence of small amounts of cadmium. The zinc content in the eel began to increase after 45 days only, and reached approximately 85 ppm after 76 days in water initially containing 5ppm of zinc. At the conclusion of the experiment (76 days), the body organs could be classified in decreasing order in zinc content (in ppm): kidneys (152), skeleton (133), skin (129), muscles (89), head (80), gills (78), digestive tract (77), liver (63) spleen-heart-air bladder (32), and mucus (15). A comparison of experimental results obtained with the zinc-cadmium mixture and cadmium alone showed that zinc decreased the cadmium content of all organs except the gills. The presence of cadmium in water did not inhibit zinc uptake. As cadmium content in water increased, then zinc content in the digestive tract and the kidneys decreased and in all cases remained lower than when zinc alone was present. In the presence of cadmium the percentage of zinc in the kidneys was always lower than the value obtained for zinc alone, and that of the digestive tract did not increase. Contamination of eels treated with 18 and 50ppb of cadmium for 29 days, then contaminated by zinc-65 (5μCi/l) while maintaining the same low cadmium content, showed no significant difference in zinc 65 uptake in the two groups. The same applied to the body organs, and particularly the digestive tract and kidneys, where the highest activity levels were observed. By weight, muscles represented approximately 30% of the total contamination after 45 days [fr
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Effect of zinc sources on yield and utilization of zinc in rice-wheat sequence
International Nuclear Information System (INIS)
Deb, D.L.
1990-01-01
A field experiment was conducted on an inceptisol of Delhi to evaluate three sources of zinc, namely, zinc sulphate, zincated urea and zinc oxide on yield and utilization of zinc in rice-wheat sequence. Results indicated that, amongst the three zinc sources, zinc sulphate and zincated urea gave the best performance in increasing the grain yield of rice whereas zinc oxide depressed the grain yield of wheat significantly when compared to other treatments. The highest Zn derived from fertilizer and its utilization was obtained with zinc sulphate for both rice and wheat crops. (author). 9 refs., 4 tabs
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Zinc blotting assay for detection of zinc binding prolamin in barley (Hordeum vulgare) grain
DEFF Research Database (Denmark)
Uddin, Mohammad Nasir; Nielsen, Ane Langkilde-Lauesen; Vincze, Eva
2014-01-01
In plants, zinc is commonly found bound to proteins. In barley (Hordeum vulgare), major storage proteins are alcohol-soluble prolamins known as hordeins, and some of them have the potential to bind or store zinc. 65Zn overlay and blotting techniques have been widely used for detecting zinc......-binding protein. However, to our knowledge so far this zinc blotting assay has never been applied to detect a prolamin fraction in barley grains. A radioactive zinc (65ZnCl2) blotting technique was optimized to detect zinc-binding prolamins, followed by development of an easy-to-follow nonradioactive colorimetric...... zinc blotting method with a zinc-sensing dye, dithizone. Hordeins were extracted from mature barley grain, separated by SDS-PAGE, blotted on a membrane, renatured, overlaid, and probed with zinc; subsequently, zinc-binding specificity of certain proteins was detected either by autoradiography or color...
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Physical vapor deposition of cubic boron nitride thin films
International Nuclear Information System (INIS)
Kester, D.J.
1991-01-01
Cubic boron nitride was successfully deposited using physical vapor-deposition methods. RF-sputtering, magnetron sputtering, dual-ion-beam deposition, and ion-beam-assisted evaporation were all used. The ion-assisted evaporation, using boron evaporation and bombardment by nitrogen and argon ions, led to successful cubic boron nitride growth over the widest and most controllable range of conditions. It was found that two factors were important for c-BN growth: bombardment of the growing film and the presence of argon. A systematic study of the deposition conditions was carried out. It was found that the value of momentum transferred into the growing from by the bombarding ions was critical. There was a very narrow transition range in which mixed cubic and hexagonal phase films were prepared. Momentum-per-atom value took into account all the variables involved in ion-assisted deposition: deposition rate, ion energy, ion flux, and ion species. No other factor led to the same control of the process. The role of temperature was also studied; it was found that at low temperatures only mixed cubic and hexagonal material are deposited
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d and f electrons in a qp-quantized cubical field
International Nuclear Information System (INIS)
Kibler, M.; Sztucki, J.
1993-03-01
A procedure for qp-quantizing a crystal-field potential V with an arbitrary symmetry G is developed. Such a procedure is applied to the case where V involves cubic components (G=0) of the degrees 4 and 6. This case corresponds to d and f electrons in a qp-quantized cubical potential. It is shown that the qp-quantization of the considered cubical potential is equivalent to a symmetry breaking of type O→D 4 . A general conjecture about this symmetry breaking phenomenon is given. (author) 21 refs
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International Nuclear Information System (INIS)
Zhu Liqun; Zhang Hui; Li Weiping; Liu Huicong
2008-01-01
Zinc powder, as active material of secondary alkaline zinc electrode, can greatly limit the performance of zinc electrode due to corrosion and dendritic growth of zinc resulting in great capacity-loss and short cycle life of the electrode. This work is devoted to modification study of zinc powder with neodymium conversion films coated directly onto it using ultrasonic immersion method for properties improvement of zinc electrodes. Scanning electron microscopy and other characterization techniques are applied to prove that neodymium conversion layers are distributing on the surface of modified zinc powder. The electrochemical performance of zinc electrodes made of such modified zinc powder is investigated through potentiodynamic polarization, potentiostatic polarization and cyclic voltammetry. The neodymium conversion films are found to have a significant effect on inhibition corrosion capability of zinc electrode in a beneficial way. It is also confirmed that the neodymium conversion coatings can obviously suppress dendritic growth of zinc electrode, which is attributed to the amelioration of deposition state of zinc. Moreover, the results of cyclic voltammetry reveal that surface modification of zinc powder enhances the cycle performance of the electrode mainly because the neodymium conversion films decrease the amounts of ZnO or Zn(OH) 2 dissolved in the electrolyte
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Blended Learning over Two Decades
Zhonggen, Yu; Yuexiu, Zhejiang
2015-01-01
The 21st century has witnessed vast amounts of research into blended learning since the conception of online learning formed the possibility of blended learning in the early 1990s. The theme of this paper is blended learning in mainstream disciplinary communities. In particular, the paper reports on findings from the last two decades which looked…
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Evaporation characteristics of ETBE-blended gasoline.
Okamoto, Katsuhiro; Hiramatsu, Muneyuki; Hino, Tomonori; Otake, Takuma; Okamoto, Takashi; Miyamoto, Hiroki; Honma, Masakatsu; Watanabe, Norimichi
2015-04-28
To reduce greenhouse gas emissions, which contribute to global warming, production of gasoline blended with ethyl tert-buthyl ether (ETBE) is increasing annually. The flash point of ETBE is higher than that of gasoline, and blending ETBE into gasoline will change the flash point and the vapor pressure. Therefore, it is expected that the fire hazard caused by ETBE-blended gasoline would differ from that caused by normal gasoline. The aim of this study was to acquire the knowledge required for estimating the fire hazard of ETBE-blended gasoline. Supposing that ETBE-blended gasoline was a two-component mixture of gasoline and ETBE, we developed a prediction model that describes the vapor pressure and flash point of ETBE-blended gasoline in an arbitrary ETBE blending ratio. We chose 8-component hydrocarbon mixture as a model gasoline, and defined the relation between molar mass of gasoline and mass loss fraction. We measured the changes in the vapor pressure and flash point of gasoline by blending ETBE and evaporation, and compared the predicted values with the measured values in order to verify the prediction model. The calculated values of vapor pressures and flash points corresponded well to the measured values. Thus, we confirmed that the change in the evaporation characteristics of ETBE-blended gasoline by evaporation could be predicted by the proposed model. Furthermore, the vapor pressure constants of ETBE-blended gasoline were obtained by the model, and then the distillation curves were developed. Copyright © 2015 Elsevier B.V. All rights reserved.
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International Nuclear Information System (INIS)
Kiilerich, S.
1987-01-01
The zinc ion is essential for the living organism. Many pathological conditions have been described as a consequence of zinc deficiency. As zinc constitutes less than 0.01 per cent of the body weight, it conventionally belongs to the group of trace elements. The method of atomic absorption spectrophotometry is used to measure the concentration of zinc in serum and urine from healthy persons. The assumptions of the method is discussed. The importance of proteinbinding, diet and the diurnal variation of serum zinc concentration is presented. Serum versus plasma zinc concentration is discussed. Reference serum zinc values from 104 normal subjects are given. Zinc in serum is almost entirely bound to proteins. A preliminary model for the estimation of the distribution of zinc between serum albumin and α 2 -macroglobulin is set up. This estimate has been examined by an ultracentrufugation method. The binding of zinc to a α 2 -macroglobulin in normal persons is appoximately 7 per cent, in patients with cirrhosis of the liver of alcoholic origin approximately 6 per cent, in patients with insulin dependent diabetes mellitus approximately 5 per cent, and in patients with chronic renal failure approximately 2 per cent. It is concluded, therefore, that for clinical purposes it is sufficient to use the concentration of total serum zinc corrected for the concentration of serum albumin. (author)
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Evaporation characteristics of ETBE-blended gasoline
International Nuclear Information System (INIS)
Okamoto, Katsuhiro; Hiramatsu, Muneyuki; Hino, Tomonori; Otake, Takuma; Okamoto, Takashi; Miyamoto, Hiroki; Honma, Masakatsu; Watanabe, Norimichi
2015-01-01
Highlights: • We chose 8-component hydrocarbon mixture as a model gasoline, and defined the molar mass of gasoline. • We proposed an evaporation model assuming a 2-component mixture of gasoline and ETBE. • We predicted the change in the vapor pressure of ETBE-blended gasoline by evaporation. • The vapor pressures were measured and compared as a means of verifying the model. • We presented the method for predicting flash points of the ETBE-blended gasoline. - Abstract: To reduce greenhouse gas emissions, which contribute to global warming, production of gasoline blended with ethyl tert-buthyl ether (ETBE) is increasing annually. The flash point of ETBE is higher than that of gasoline, and blending ETBE into gasoline will change the flash point and the vapor pressure. Therefore, it is expected that the fire hazard caused by ETBE-blended gasoline would differ from that caused by normal gasoline. The aim of this study was to acquire the knowledge required for estimating the fire hazard of ETBE-blended gasoline. Supposing that ETBE-blended gasoline was a two-component mixture of gasoline and ETBE, we developed a prediction model that describes the vapor pressure and flash point of ETBE-blended gasoline in an arbitrary ETBE blending ratio. We chose 8-component hydrocarbon mixture as a model gasoline, and defined the relation between molar mass of gasoline and mass loss fraction. We measured the changes in the vapor pressure and flash point of gasoline by blending ETBE and evaporation, and compared the predicted values with the measured values in order to verify the prediction model. The calculated values of vapor pressures and flash points corresponded well to the measured values. Thus, we confirmed that the change in the evaporation characteristics of ETBE-blended gasoline by evaporation could be predicted by the proposed model. Furthermore, the vapor pressure constants of ETBE-blended gasoline were obtained by the model, and then the distillation curves were
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Evaporation characteristics of ETBE-blended gasoline
Energy Technology Data Exchange (ETDEWEB)
Okamoto, Katsuhiro, E-mail: okamoto@nrips.go.jp [National Research Institute of Police Science, 6-3-1 Kashiwanoha, Kashiwa, Chiba 277-0882 (Japan); Hiramatsu, Muneyuki [Yamanashi Prefectural Police H.Q., 312-4 Kubonakajima, Isawa-cho, Usui, Yamanashi 406-0036 (Japan); Hino, Tomonori; Otake, Takuma [Metropolitan Police Department, 2-1-1 Kasumigaseki, Chiyoda-ku, Tokyo 100-8929 (Japan); Okamoto, Takashi; Miyamoto, Hiroki; Honma, Masakatsu; Watanabe, Norimichi [National Research Institute of Police Science, 6-3-1 Kashiwanoha, Kashiwa, Chiba 277-0882 (Japan)
2015-04-28
Highlights: • We chose 8-component hydrocarbon mixture as a model gasoline, and defined the molar mass of gasoline. • We proposed an evaporation model assuming a 2-component mixture of gasoline and ETBE. • We predicted the change in the vapor pressure of ETBE-blended gasoline by evaporation. • The vapor pressures were measured and compared as a means of verifying the model. • We presented the method for predicting flash points of the ETBE-blended gasoline. - Abstract: To reduce greenhouse gas emissions, which contribute to global warming, production of gasoline blended with ethyl tert-buthyl ether (ETBE) is increasing annually. The flash point of ETBE is higher than that of gasoline, and blending ETBE into gasoline will change the flash point and the vapor pressure. Therefore, it is expected that the fire hazard caused by ETBE-blended gasoline would differ from that caused by normal gasoline. The aim of this study was to acquire the knowledge required for estimating the fire hazard of ETBE-blended gasoline. Supposing that ETBE-blended gasoline was a two-component mixture of gasoline and ETBE, we developed a prediction model that describes the vapor pressure and flash point of ETBE-blended gasoline in an arbitrary ETBE blending ratio. We chose 8-component hydrocarbon mixture as a model gasoline, and defined the relation between molar mass of gasoline and mass loss fraction. We measured the changes in the vapor pressure and flash point of gasoline by blending ETBE and evaporation, and compared the predicted values with the measured values in order to verify the prediction model. The calculated values of vapor pressures and flash points corresponded well to the measured values. Thus, we confirmed that the change in the evaporation characteristics of ETBE-blended gasoline by evaporation could be predicted by the proposed model. Furthermore, the vapor pressure constants of ETBE-blended gasoline were obtained by the model, and then the distillation curves were
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National Oceanic and Atmospheric Administration, Department of Commerce — The Blend was the system used by the NMFS Alaska Regional Office to monitor groundfish catch from 1991 until 2002. The Blend system combined data from industry...
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Impact of residual elements on zinc quality in the production of zinc oxide
Czech Academy of Sciences Publication Activity Database
Luptáková, Natália; Dymáček, Petr; Pešlová, F.; Jurkovič, Z.; Barborák, O.; Stodola, J.
2016-01-01
Roč. 55, č. 3 (2016), s. 407-410 ISSN 0543-5846 Institutional support: RVO:68081723 Keywords : zinc * metallography * microstructure of zinc * zinc oxide * production of zinc oxide Subject RIV: JG - Metallurgy Impact factor: 0.959, year: 2014
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Kjellerup, Lasse; Winther, Anne-Marie L.; Wilson, Duncan; Fuglsang, Anja T.
2018-01-01
Zinc is an essential micronutrient, required for a range of zinc-dependent enzymes and transcription factors. In mammalian cells, zinc serves as a second messenger molecule. However, a role for zinc in signaling has not yet been established in the fungal kingdom. Here, we used the intracellular zinc reporter, zinbo-5, which allowed visualization of zinc in the endoplasmic reticulum and other components of the internal membrane system in Candida albicans. We provide evidence for a link between cyclic AMP/PKA- and zinc-signaling in this major human fungal pathogen. Glucose stimulation, which triggers a cyclic AMP spike in this fungus resulted in rapid intracellular zinc mobilization and this “zinc flux” could be stimulated with phosphodiesterase inhibitors and blocked via inhibition of adenylate cyclase or PKA. A similar mobilization of intracellular zinc was generated by stimulation of cells with extracellular zinc and this effect could be reversed with the chelator EDTA. However, zinc-induced zinc flux was found to be cyclic AMP independent. In summary, we show that activation of the cyclic AMP/PKA pathway triggers intracellular zinc mobilization in a fungus. To our knowledge, this is the first described link between cyclic AMP signaling and zinc homeostasis in a human fungal pathogen. PMID:29619016
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Reactivation in vitro of zinc-requiring apo-enzymes by rat liver zinc-thionein
Udom, Albert O.; Brady, Frank O.
1980-01-01
The ability of rat liver zinc-thionein to donate its metal to the apo-enzymes of the zinc enzymes horse liver alcohol dehydrogenase, yeast aldolase, thermolysin, Escherichia coli alkaline phosphatase and bovine erythrocyte carbonic anhydrase was investigated. Zinc-thionein was as good as, or better than, ZnSO4, Zn(CH3CO2)2 or Zn(NO3)2 in donating its zinc to these apo-enzymes. Apo-(alcohol dehydrogenase) could not be reactivated by zinc salts or by zinc-thionein. Incubation of the other apo-e...
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Entanglement in miscible blends
Watanabe, Hiroshi
2010-03-01
The entanglement length Le of polymer chains (corresponding to the entanglement molecular weight Me) is not an intrinsic material parameter but changes with the interaction with surrounding chains. For miscible blends of cis-polyisoprene (PI) and poly(tert-butyl styrene) (PtBS), changes of Le on blending was examined. It turned out that the Le averaged over the number fractions of the Kuhn segments of the components (PI and PtBS) satisfactorily describes the viscoelastic behavior of pseudo-monodisperse blends in which the terminal relaxation time is the same for PI and PtBS.
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Miscibility evolution of polycarbonate/polystyrene blends during compounding
DEFF Research Database (Denmark)
Chuai, Chengzhi; Almdal, Kristoffer; Johannsen, Ib
2002-01-01
The miscibility evolution of polycarbonate/polystyrene (PC/PS) blends during the compounding process in three blending methods of industrial relevance, namely melt blending, remelt blending in a twin-screw extruder and third melt blending in an injection molding machine, was investigated...... polymer in the other. The observed solubility strongly depends on blend composition and blending method. The T-g measurements showed maximum mutual solubility around 50/50 composition. The miscibility of PC/PS blended after the third stage (melt injection molding) was higher than that after the first...... by measuring their glass transition temperatures (T-g) and their specific heat increment (DeltaC(p)). Differential scanning calorimetry (DSC) was used to examine nine blend compositions. Shifts in glass transition temperature (T-g) of the two phases in melt-mixed PC/PS blends suggest partial miscibility of one...
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Choudapur, V. H.; Bennal, A. S.; Raju, A. B.
2018-04-01
The ZnS nanomaterial is synthesized by hydrothermal method under optimized conditions using Zinc acetate and sodium sulphide as precursors. The Zinc Sulphide thin films are obtained by simple spin coating method with high optical transmittance. The prepared thin films are adhesive and uniform. The x-ray diffraction analysis showed that the films are polycrystalline in cubic phase with the preferred orientation along (111) direction. Current-voltage curves were recorded at room temperature using Keithley 617 programmable electrometer and conductivity is calculated for the film coated on ITO by two probe method. The pH of the solution is varied by using ammonia and hydrochloric acid. The comparative studies of effect of pH on the morphology, crystallanity and optoelectronic properties of the films are studied. It is observed that the pH of the solution has large influence on optoelectronic properties. The thin film prepared with neutral pH has higher crystallanity, bandgap and conductivity as compared to the samples prepared in acidic or basic solutions.
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Minimal knotted polygons in cubic lattices
International Nuclear Information System (INIS)
Van Rensburg, E J Janse; Rechnitzer, A
2011-01-01
In this paper we examine numerically the properties of minimal length knotted lattice polygons in the simple cubic, face-centered cubic, and body-centered cubic lattices by sieving minimal length polygons from a data stream of a Monte Carlo algorithm, implemented as described in Aragão de Carvalho and Caracciolo (1983 Phys. Rev. B 27 1635), Aragão de Carvalho et al (1983 Nucl. Phys. B 215 209) and Berg and Foester (1981 Phys. Lett. B 106 323). The entropy, mean writhe, and mean curvature of minimal length polygons are computed (in some cases exactly). While the minimal length and mean curvature are found to be lattice dependent, the mean writhe is found to be only weakly dependent on the lattice type. Comparison of our results to numerical results for the writhe obtained elsewhere (see Janse van Rensburg et al 1999 Contributed to Ideal Knots (Series on Knots and Everything vol 19) ed Stasiak, Katritch and Kauffman (Singapore: World Scientific), Portillo et al 2011 J. Phys. A: Math. Theor. 44 275004) shows that the mean writhe is also insensitive to the length of a knotted polygon. Thus, while these results for the mean writhe and mean absolute writhe at minimal length are not universal, our results demonstrate that these values are quite close the those of long polygons regardless of the underlying lattice and length
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Kirgiz, Mehmet Serkan
2014-01-01
Effects of chemical compositions changes of blended-cement pastes (BCPCCC) on some strength gains of blended cement mortars (BCMSG) were monitored in order to gain a better understanding for developments of hydration and strength of blended cements. Blended cements (BC) were prepared by blending of 5% gypsum and 6%, 20%, 21%, and 35% marble powder (MP) or 6%, 20%, 21%, and 35% brick powder (BP) for CEMI42.5N cement clinker and grinding these portions in ball mill at 30 (min). Pastes and mortars, containing the MP-BC and the BP-BC and the reference cement (RC) and tap water and standard mortar sand, were also mixed and they were cured within water until testing. Experiments included chemical compositions of pastes and compressive strengths (CS) and flexural strengths (FS) of mortars were determined at 7th-day, 28th-day, and 90th-day according to TS EN 196-2 and TS EN 196-1 present standards. Experimental results indicated that ups and downs of silica oxide (SiO2), sodium oxide (Na2O), and alkali at MP-BCPCC and continuously rising movement of silica oxide (SiO2) at BP-BCPCC positively influenced CS and FS of blended cement mortars (BCM) in comparison with reference mortars (RM) at whole cure days as MP up to 6% or BP up to 35% was blended for cement. PMID:24587737
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Directory of Open Access Journals (Sweden)
Mehmet Serkan Kirgiz
2014-01-01
Full Text Available Effects of chemical compositions changes of blended-cement pastes (BCPCCC on some strength gains of blended cement mortars (BCMSG were monitored in order to gain a better understanding for developments of hydration and strength of blended cements. Blended cements (BC were prepared by blending of 5% gypsum and 6%, 20%, 21%, and 35% marble powder (MP or 6%, 20%, 21%, and 35% brick powder (BP for CEMI42.5N cement clinker and grinding these portions in ball mill at 30 (min. Pastes and mortars, containing the MP-BC and the BP-BC and the reference cement (RC and tap water and standard mortar sand, were also mixed and they were cured within water until testing. Experiments included chemical compositions of pastes and compressive strengths (CS and flexural strengths (FS of mortars were determined at 7th-day, 28th-day, and 90th-day according to TS EN 196-2 and TS EN 196-1 present standards. Experimental results indicated that ups and downs of silica oxide (SiO2, sodium oxide (Na2O, and alkali at MP-BCPCC and continuously rising movement of silica oxide (SiO2 at BP-BCPCC positively influenced CS and FS of blended cement mortars (BCM in comparison with reference mortars (RM at whole cure days as MP up to 6% or BP up to 35% was blended for cement.
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Introducing blended e-learning course design
DEFF Research Database (Denmark)
Gyamfi, Samuel Adu; Ryberg, Thomas
2012-01-01
In the face of diminishing education budgets in higher education, blended learning has been found to be a viable and effective approach to deliver high-quality, up-to-date, on-demand solutions to developing cross-curricular skills of undergraduates. However, research has also shown that blended...... learning solutions do not often live up to the potential of the approach or fail to produce the intended results because the students are not always equipped to handle the technical, psychological and organisational challenges of blended learning approaches. This project surveyed seventy-five first year...... the students’ e-readiness for an implementation of a blend-ed course design....
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Transformation of zinc hydroxide chloride monohydrate to crystalline zinc oxide.
Moezzi, Amir; Cortie, Michael; McDonagh, Andrew
2016-04-25
Thermal decomposition of layered zinc hydroxide double salts provides an interesting alternative synthesis for particles of zinc oxide. Here, we examine the sequence of changes occurring as zinc hydroxide chloride monohydrate (Zn5(OH)8Cl2·H2O) is converted to crystalline ZnO by thermal decomposition. The specific surface area of the resultant ZnO measured by BET was 1.3 m(2) g(-1). A complicating and important factor in this process is that the thermal decomposition of zinc hydroxide chloride is also accompanied by the formation of volatile zinc-containing species under certain conditions. We show that this volatile compound is anhydrous ZnCl2 and its formation is moisture dependent. Therefore, control of atmospheric moisture is an important consideration that affects the overall efficiency of ZnO production by this process.
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International Nuclear Information System (INIS)
Lock, K.; Janssen, C.R.
2005-01-01
Pollution induced community tolerance (PICT) is based on the phenomenon that toxic effects reduce survival of the most sensitive organisms, thus increasing community tolerance. Community tolerance for a contaminant is thus a strong indicator for the presence of that contaminant at the level of adverse concentrations. Here we assessed PICT in 11 soils contaminated with zinc runoff from galvanised electricity pylons and 11 reference soils sampled at 10 m distance from these pylons. Using PICT, the influence of background concentration and bioavailability of zinc on zinc sensitivity and functional diversity of microbial communities was assessed. Zinc sensitivity of microbial communities decreased significantly with increasing zinc concentrations in pore water and calcium chloride extracted fraction while no significant relationship was found with total zinc concentration in the soil. It was also found that functional diversity of microbial communities decreased with increasing zinc concentrations, indicating that increased tolerance is indeed an undesirable phenomenon when environmental quality is considered. The hypothesis that zinc sensitivity of microbial communities is related to background zinc concentration in pore water could not be confirmed. - Zinc sensitivity of microbial communities and functional diversity decrease with increasing zinc concentration in the pore water
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Electrochemical synthesis and characterization of zinc carbonate and zinc oxide nanoparticles
Pourmortazavi, Seied Mahdi; Marashianpour, Zahra; Karimi, Meisam Sadeghpour; Mohammad-Zadeh, Mohammad
2015-11-01
Zinc oxide and its precursor i.e., zinc carbonate is widely utilized in various fields of industry, especially in solar energy conversion, optical, and inorganic pigments. In this work, a facile and clean electrodeposition method was utilized for the synthesis of zinc carbonate nanoparticles. Also, zinc oxide nanoparticles were produced by calcination of the prepared zinc carbonate powder. Zinc carbonate nanoparticles with different sizes were electrodeposited by electrolysis of a zinc plate as anode in the solution of sodium carbonate. It was found that the particle size of zinc carbonate might be tuned by process parameters, i.e., electrolysis voltage, carbonate ion concentration, solvent composition and stirring rate of the electrolyte solution. An orthogonal array design was utilized to identify the optimum experimental conditions. The experimental results showed that the minimum size of the electrodeposited ZnCO3 particles is about 24 nm whereas the maximum particle size is around 40 nm. The TG-DSC studies of the nanoparticles indicated that the main thermal degradation of ZnCO3 occurs in two steps over the temperature ranges of 150-250 and 350-400 °C. The electrosynthesized ZnCO3 nanoparticles were calcined at the temperature of 600 °C to prepare ZnO nanoparticles. The prepared ZnCO3 and ZnO nanoparticles were characterized by SEM, X-ray diffraction (XRD), and FT-IR techniques.
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Energy Technology Data Exchange (ETDEWEB)
Zhang Lin [Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang 330031 (China); Institute of Polymers, Nanchang University, 999 Xuefu Avenue, Nanchang 330031 (China); Li Fan, E-mail: lfan@ncu.edu.cn [Institute of Polymers, Nanchang University, 999 Xuefu Avenue, Nanchang 330031 (China); Chen Yiwang, E-mail: ywchen@ncu.edu.cn [Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang 330031 (China); Institute of Polymers, Nanchang University, 999 Xuefu Avenue, Nanchang 330031 (China); Wang Xiaofeng [Institute of Polymers, Nanchang University, 999 Xuefu Avenue, Nanchang 330031 (China)
2011-08-15
In this paper, a new and simple approach for in-situ preparation of transparent ZnO/poly(metyl methacrylate) (ZnO/PMMA) nanocomposite films was developed. Poly(methyl methacrylate)-co-poly(zinc methacrylate acetate) (PMMA-co-PZnMAAc) copolymer was synthesized via free-radical polymerization between methyl methacrylate (MMA) and zinc methacrylate acetate (ZnMAAc), where asymmetric ZnMAAc with only one terminal double bond (C=C) was applied to act as the precursor for ZnO nanocrystals and could avoid cross-link. Subsequently, transparent ZnO/PMMA nanocomposite films were obtained by in-situ thermal decomposition. Scanning electron microscope (SEM) image revealed that ZnO nanocrystals were homogeneously dispersed in PMMA matrix. With thermal decomposition time increasing, the absorption intensity in UV region and photoluminescence intensity of ZnO/PMMA nanocomposite films enhanced. However, the optical properties diminished when the thermal decomposition temperature increased. The TGA measurement displayed ZnO/PMMA nanocomposite films prepared by the in-situ synthesis method possessed better thermal stability compared with those prepared by the physical blending method and pristine PMMA films. - Highlights: > ZnO/PMMA hybrid films were prepared via free-radical polymerization and in-situ thermal decomposition. > ZnO NCs are homogeneously dispersed in the PMMA matrix and these films have good optical properties. > Thermal stability of these films is improved compared with those of physically blending ones.
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International Nuclear Information System (INIS)
Zhang Lin; Li Fan; Chen Yiwang; Wang Xiaofeng
2011-01-01
In this paper, a new and simple approach for in-situ preparation of transparent ZnO/poly(metyl methacrylate) (ZnO/PMMA) nanocomposite films was developed. Poly(methyl methacrylate)-co-poly(zinc methacrylate acetate) (PMMA-co-PZnMAAc) copolymer was synthesized via free-radical polymerization between methyl methacrylate (MMA) and zinc methacrylate acetate (ZnMAAc), where asymmetric ZnMAAc with only one terminal double bond (C=C) was applied to act as the precursor for ZnO nanocrystals and could avoid cross-link. Subsequently, transparent ZnO/PMMA nanocomposite films were obtained by in-situ thermal decomposition. Scanning electron microscope (SEM) image revealed that ZnO nanocrystals were homogeneously dispersed in PMMA matrix. With thermal decomposition time increasing, the absorption intensity in UV region and photoluminescence intensity of ZnO/PMMA nanocomposite films enhanced. However, the optical properties diminished when the thermal decomposition temperature increased. The TGA measurement displayed ZnO/PMMA nanocomposite films prepared by the in-situ synthesis method possessed better thermal stability compared with those prepared by the physical blending method and pristine PMMA films. - Highlights: → ZnO/PMMA hybrid films were prepared via free-radical polymerization and in-situ thermal decomposition. → ZnO NCs are homogeneously dispersed in the PMMA matrix and these films have good optical properties. → Thermal stability of these films is improved compared with those of physically blending ones.
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The relative efficiency of zinc carriers on growth and zinc nutrition of corn
International Nuclear Information System (INIS)
Prasad, B.; Sinha, K.
1981-01-01
A comparison of different zinc carriers showed that application of Zn-DTPA, Zn-EDTA, Zn-fulvate and ZnSO 4 significantly increased the dry matter yield and zinc uptake by corn over the control treatment where no zinc was applied. The chelates in particular enhanced to a greater extent the uptake of both native and applied sources than that observed with ZnSO 4 as the zinc carrier. Both the dry matter yield and zinc uptake by corn showed a positive and significant relationship with self-diffusion coefficient of zinc showing thereby that diffusion contributed mainly the supply of Zn from the ambient soil matrix to plant roots. The effectiveness of the chelates varied depending on their capacity to retain Zn in a soluble form in the soil solution. It is evident that zinc nutrition of plants in alkaline and calcareous soils can be more effectively regulated by both synthetic and natural chelates or organic manures which contain substantial amount of complexed zinc. (orig.)
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Cubic Pencils and Painlev\\'e Hamiltonians
Kajiwara, Kenji; Masuda, Tetsu; Noumi, Masatoshi; Ohta, Yasuhiro; Yamada, Yasuhiko
2004-01-01
We present a simple heuristic method to derive the Painlev\\'e differential equations from the corresponding geometry of rational surafces. We also give a direct relationship between the cubic pencils and Seiberg-Witten curves.
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Energy Technology Data Exchange (ETDEWEB)
Nofar, M. [Center for High Performance Polymer and Composite Systems (CREPEC), Chemical Engineering Department, Polytechnique Montreal, Montreal, Quebec H3T 1J4, Canada and CREPEC, Department of Chemical Engineering, McGill University, Montreal, Quebec H3A 2B2 (Canada); Heuzey, M. C.; Carreau, P. J., E-mail: pierre.carreau@polymtl.ca [Center for High Performance Polymer and Composite Systems (CREPEC), Chemical Engineering Department, Polytechnique Montreal, Montreal, Quebec H3T 1J4 (Canada); Kamal, M. R. [CREPEC, Department of Chemical Engineering, McGill University, Montreal, Quebec H3A 2B2 (Canada); Randall, J. [NatureWorks LLC, 15305 Minnetonka Boulevard, Minnetonka, Minnesota 55345 (United States)
2016-07-15
Blends containing 75 wt. % of an amorphous polylactide (PLA) with two different molecular weights and 25 wt. % of a poly[(butylene adipate)-co-terephthalate] (PBAT) were prepared using either a Brabender batch mixer or a twin-screw extruder. These compounds were selected because blending PLA with PBAT can overcome various drawbacks of PLA such as its brittleness and processability limitations. In this study, we investigated the effects of varying the molecular weight of the PLA matrix and of two different mixing processes on the blend morphology and, further, on droplet coalescence during shearing. The rheological properties of these blends were investigated and the interfacial properties were analyzed using the Palierne emulsion model. Droplet coalescence was investigated by applying shear flows of 0.05 and 0.20 s{sup −1} at a fixed strain of 60. Subsequently, small amplitude oscillatory shear tests were conducted to investigate changes in the viscoelastic properties. The morphology of the blends was also examined using scanning electron microscope (SEM) micrographs. It was observed that the PBAT droplets were much smaller when twin-screw extrusion was used for the blend preparation. Shearing at 0.05 s{sup −1} induced significant droplet coalescence in all blends, but coalescence and changes in the viscoelastic properties were much more pronounced for the PLA-PBAT blend based on a lower molecular weight PLA. The viscoelastic responses were also somehow affected by the thermal degradation of the PLA matrix during the experiments.
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International Nuclear Information System (INIS)
Nofar, M.; Heuzey, M. C.; Carreau, P. J.; Kamal, M. R.; Randall, J.
2016-01-01
Blends containing 75 wt. % of an amorphous polylactide (PLA) with two different molecular weights and 25 wt. % of a poly[(butylene adipate)-co-terephthalate] (PBAT) were prepared using either a Brabender batch mixer or a twin-screw extruder. These compounds were selected because blending PLA with PBAT can overcome various drawbacks of PLA such as its brittleness and processability limitations. In this study, we investigated the effects of varying the molecular weight of the PLA matrix and of two different mixing processes on the blend morphology and, further, on droplet coalescence during shearing. The rheological properties of these blends were investigated and the interfacial properties were analyzed using the Palierne emulsion model. Droplet coalescence was investigated by applying shear flows of 0.05 and 0.20 s"−"1 at a fixed strain of 60. Subsequently, small amplitude oscillatory shear tests were conducted to investigate changes in the viscoelastic properties. The morphology of the blends was also examined using scanning electron microscope (SEM) micrographs. It was observed that the PBAT droplets were much smaller when twin-screw extrusion was used for the blend preparation. Shearing at 0.05 s"−"1 induced significant droplet coalescence in all blends, but coalescence and changes in the viscoelastic properties were much more pronounced for the PLA-PBAT blend based on a lower molecular weight PLA. The viscoelastic responses were also somehow affected by the thermal degradation of the PLA matrix during the experiments.
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Morphology Evolution of Polycarbonate-Polystyrene Blends During Compounding
DEFF Research Database (Denmark)
Chuai, Chengzhi; Almdal, Kristoffer; Johannsen, Ib
2001-01-01
The morphology evolution of polycarbonate-polystyrene (PC/PS) blends during the compounding process in three blending methods of industrial relevance, namely melt blending, re-melt blending in a twin-screw extruder and tri-melt blending in an injection-moulding machine, was investigated using......-empirical model. The results show that the formation of co-continuous morphology strongly depends on blend composition and melt blending method, whereas the model prediction for phase inversion deviates from the experimental values. Further, we found that the initial mechanism of morphology evolution involves...... scanning electron microscopy (SEM) Co examine nine blend compositions. Blends were prepared at compositions where phase inversion was expected to occur according to model predictions. The experimental results were compared to the values of the point of phase inversion calculated with the semi...
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Integrable peakon equations with cubic nonlinearity
International Nuclear Information System (INIS)
Hone, Andrew N W; Wang, J P
2008-01-01
We present a new integrable partial differential equation found by Vladimir Novikov. Like the Camassa-Holm and Degasperis-Procesi equations, this new equation admits peaked soliton (peakon) solutions, but it has nonlinear terms that are cubic, rather than quadratic. We give a matrix Lax pair for V Novikov's equation, and show how it is related by a reciprocal transformation to a negative flow in the Sawada-Kotera hierarchy. Infinitely many conserved quantities are found, as well as a bi-Hamiltonian structure. The latter is used to obtain the Hamiltonian form of the finite-dimensional system for the interaction of N peakons, and the two-body dynamics (N = 2) is explicitly integrated. Finally, all of this is compared with some analogous results for another cubic peakon equation derived by Zhijun Qiao. (fast track communication)
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Zinc triggers microglial activation.
Kauppinen, Tiina M; Higashi, Youichirou; Suh, Sang Won; Escartin, Carole; Nagasawa, Kazuki; Swanson, Raymond A
2008-05-28
Microglia are resident immune cells of the CNS. When stimulated by infection, tissue injury, or other signals, microglia assume an activated, "ameboid" morphology and release matrix metalloproteinases, reactive oxygen species, and other proinflammatory factors. This innate immune response augments host defenses, but it can also contribute to neuronal death. Zinc is released by neurons under several conditions in which microglial activation occurs, and zinc chelators can reduce neuronal death in animal models of cerebral ischemia and neurodegenerative disorders. Here, we show that zinc directly triggers microglial activation. Microglia transfected with a nuclear factor-kappaB (NF-kappaB) reporter gene showed a severalfold increase in NF-kappaB activity in response to 30 microm zinc. Cultured mouse microglia exposed to 15-30 microm zinc increased nitric oxide production, increased F4/80 expression, altered cytokine expression, and assumed the activated morphology. Zinc-induced microglial activation was blocked by inhibiting NADPH oxidase, poly(ADP-ribose) polymerase-1 (PARP-1), or NF-kappaB activation. Zinc injected directly into mouse brain induced microglial activation in wild-type mice, but not in mice genetically lacking PARP-1 or NADPH oxidase activity. Endogenous zinc release, induced by cerebral ischemia-reperfusion, likewise induced a robust microglial reaction, and this reaction was suppressed by the zinc chelator CaEDTA. Together, these results suggest that extracellular zinc triggers microglial activation through the sequential activation of NADPH oxidase, PARP-1, and NF-kappaB. These findings identify a novel trigger for microglial activation and a previously unrecognized mechanism by which zinc may contribute to neurological disorders.
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Shearman, Gemma C; Khoo, Bee J; Motherwell, Mary-Lynn; Brakke, Kenneth A; Ces, Oscar; Conn, Charlotte E; Seddon, John M; Templer, Richard H
2007-06-19
Inverse bicontinuous cubic lyotropic phases are a complex solution to the dilemma faced by all self-assembled water-amphiphile systems: how to satisfy the incompatible requirements for uniform interfacial curvature and uniform molecular packing. The solution reached in this case is for the water-amphiphile interfaces to deform hyperbolically onto triply periodic minimal surfaces. We have previously suggested that although the molecular packing in these structures is rather uniform the relative phase behavior of the gyroid, double diamond, and primitive inverse bicontinuous cubic phases can be understood in terms of subtle differences in packing frustration. In this work, we have calculated the packing frustration for these cubics under the constraint that their interfaces have constant mean curvature. We find that the relative packing stress does indeed differ between phases. The gyroid cubic has the least packing stress, and at low water volume fraction, the primitive cubic has the greatest packing stress. However, at very high water volume fraction, the double diamond cubic becomes the structure with the greatest packing stress. We have tested the model in two ways. For a system with a double diamond cubic phase in excess water, the addition of a hydrophobe may release packing frustration and preferentially stabilize the primitive cubic, since this has previously been shown to have lower curvature elastic energy. We have confirmed this prediction by adding the long chain alkane tricosane to 1-monoolein in excess water. The model also predicts that if one were able to hydrate the double diamond cubic to high water volume fractions, one should destabilize the phase with respect to the primitive cubic. We have found that such highly swollen metastable bicontinuous cubic phases can be formed within onion vesicles. Data from monoelaidin in excess water display a well-defined transition, with the primitive cubic appearing above a water volume fraction of 0.75. Both of
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Deng, Bo; Zhou, Xihong; Wu, Jie; Long, Ciming; Yao, Yajun; Peng, Hongxing; Wan, Dan; Wu, Xin
2017-10-01
An experiment was conducted to compare the effects of zinc sulfate (ZS) and tribasic zinc sulfate (TBZ) as sources of supplemental zinc on growth performance, serum zinc (Zn) content and messenger RNA (mRNA) expression of Zn transporters (ZnT1/ZnT2/ZnT5/ZIP4/DMT1) of young growing pigs. A total of 96 Duroc × Landrace × Yorkshire pigs were randomly allotted to two treatments and were fed a basal diet supplemented with 100 mg/kg Zn from either ZS or TBZ for 28 days. Feed : gain ratio in pigs fed TBZ were lower (P zinc transporter in either duodenum or jejunum of pigs fed TBZ were higher (P < 0.05) than pigs fed ZS. These results indicate that TBZ is more effective in serum Zn accumulation and intestinal Zn absorption, and might be a potential substitute for ZS in young growing pigs. © 2017 Japanese Society of Animal Science.
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Availability of native and fertilizer zinc in some Indian soils: studies with 65Zinc
International Nuclear Information System (INIS)
Chaudhury, J.; Deb, D.L.
1979-01-01
Isotopically exchangeable zinc (Et values) was determined by different methods in some soils having pH(H 2 O) varying from 3.05 to 8.40 using 65 Zn. The Et values obtained using different extractants showed significant correlation with available zinc, organic carbon and soil pH. The recovery of applied zinc in the aqueous phase was less than one percent in most of the soils having pH higher than 7.0. Application of zinc with complexing agents like DTPA and EDTA increased the recovery of applied zinc in the solution to about 95 percent. Soil pH, organic C and DTPA extractable zinc showed significant relationship with the recovery of applied zinc under different treatments. Use of EDTA and DTPA extractants reduced the zinc buffering capacity of soil to a value less than one, irrespective of the initial pH of the soil, whereas the values were comparatively higher in presence of different levels of zinc carrier. (auth.)
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International Nuclear Information System (INIS)
Singh, Archana; Singh, Ajendra; Singh, Satyendra; Tandon, Poonam; Yadav, B.C.; Yadav, R.R.
2015-01-01
Highlights: • Fabrication of zinc ferrite thin film LPG and CO 2 gas sensors. • Morphological growth of nanorods. • Significant advancement towards the fabrication of a reliable LPG sensor. • A new pathway to produce nanorods as sensorial material. - Abstract: In the present communication, nanorods of zinc ferrite was synthesized and fabricated by employing sol–gel spin coating process. The synthesized material was characterized using X-ray diffraction, scanning electron microscopy, acoustic particle sizer, atomic force microscopy, UV–visible absorption and infrared spectroscopic techniques. Thermal properties were investigated using differential scanning calorimetry. The XRD reveals cubic spinel structure with minimum crystallite size 10 nm. SEM image of the film shows porous surface morphology with uniform distribution of nanorods. The band gap of the zinc ferrite nanorods was found 3.80 eV using the Tauc plot. ZnFe 2 O 4 shows weak super paramagnetic behavior at room temperature investigated using the vibrating sample magnetometer. Further, the liquefied petroleum gas (LPG) and carbon dioxide gas (CO 2 ) sensing properties of the fabricated film were investigated at room temperature (25 °C). More variations in electrical resistance were observed for LPG in comparison to CO 2 gas. The parameters such as lattice constant, X-ray density, porosity and specific surface area were also calculated for the better understanding of the observed gas sensing properties. High sensitivity and percentage sensor response, small response and recovery times, good reproducibility and stability characterized the fabricated sensor for the detection of LPG at room temperature
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Energy Technology Data Exchange (ETDEWEB)
Singh, Archana; Singh, Ajendra [Macromolecular Research Laboratory, Department of Physics, University of Lucknow, Lucknow 226007, U.P. (India); Singh, Satyendra, E-mail: satyendra_nano84@rediffmail.com [Department of Physics, University of Allahabad, Allahabad 211002, U.P. (India); Tandon, Poonam [Macromolecular Research Laboratory, Department of Physics, University of Lucknow, Lucknow 226007, U.P. (India); Yadav, B.C. [Department of Applied Physics, School for Physical Sciences, Babasaheb Bhimrao Ambedkar University, Lucknow 226025, U.P. (India); Yadav, R.R. [Department of Physics, University of Allahabad, Allahabad 211002, U.P. (India)
2015-01-05
Highlights: • Fabrication of zinc ferrite thin film LPG and CO{sub 2} gas sensors. • Morphological growth of nanorods. • Significant advancement towards the fabrication of a reliable LPG sensor. • A new pathway to produce nanorods as sensorial material. - Abstract: In the present communication, nanorods of zinc ferrite was synthesized and fabricated by employing sol–gel spin coating process. The synthesized material was characterized using X-ray diffraction, scanning electron microscopy, acoustic particle sizer, atomic force microscopy, UV–visible absorption and infrared spectroscopic techniques. Thermal properties were investigated using differential scanning calorimetry. The XRD reveals cubic spinel structure with minimum crystallite size 10 nm. SEM image of the film shows porous surface morphology with uniform distribution of nanorods. The band gap of the zinc ferrite nanorods was found 3.80 eV using the Tauc plot. ZnFe{sub 2}O{sub 4} shows weak super paramagnetic behavior at room temperature investigated using the vibrating sample magnetometer. Further, the liquefied petroleum gas (LPG) and carbon dioxide gas (CO{sub 2}) sensing properties of the fabricated film were investigated at room temperature (25 °C). More variations in electrical resistance were observed for LPG in comparison to CO{sub 2} gas. The parameters such as lattice constant, X-ray density, porosity and specific surface area were also calculated for the better understanding of the observed gas sensing properties. High sensitivity and percentage sensor response, small response and recovery times, good reproducibility and stability characterized the fabricated sensor for the detection of LPG at room temperature.
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65Zinc and endogenous zinc content and distribution in islets in relationship to insulin content
International Nuclear Information System (INIS)
Figlewicz, D.P.; Forhan, S.E.; Hodgson, A.T.; Grodsky, G.M.
1984-01-01
Uptake of 65 Zn and distribution of 65 Zn, total zinc, and insulin were measured in rat islets and islet granules under different conditions of islet culture. Specific activity of islet zinc ( 65 Zn/zinc) was less than 15% that of extracellular zinc even after 48 h. In contrast, once in the islet, 65 Zn approached 70% of equilibrium with granular zinc in 24 h and apparent equilibrium by 48 h. During a 24-h culture, at either high or low glucose, reduction of both islet zinc and insulin occurred. However, zinc depletion was greater than that predicted if zinc loss was proportional to insulin depletion and occurred only from the granular compartment, which represents only one third of the total islet zinc. Extension of culture to 48 h caused additional insulin depletion, but islet zinc was unchanged. Omission of calcium during the 48-h culture caused a predicted increase in insulin retention, presumably by inhibiting secretion; however, zinc retention was not increased proportionately. Pretreatment of rats with tolbutamide caused a massive depletion of insulin stored in isolated islets, with little change in total islet zinc; subsequent culture of these islets resulted in a greater loss of granular zinc than predicted from the small loss of granular insulin. None of the conditions tested affected the percentage of either 65 Zn or total zinc that was distributed in the islet granules. Results show that zinc exists in a metabolically labile islet compartment(s) as well as in secretory granules; and extra-granular zinc, although not directly associated with insulin storage, may act as a reservoir for granular zinc and may regulate insulin synthesis, storage, and secretion in ways as yet unknown
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The Combinatorial Rigidity Conjecture is False for Cubic Polynomials
DEFF Research Database (Denmark)
Henriksen, Christian
2003-01-01
We show that there exist two cubic polynomials with connected Julia sets which are combinatorially equivalent but not topologically conjugate on their Julia sets. This disproves a conjecture by McMullen from 1995.......We show that there exist two cubic polynomials with connected Julia sets which are combinatorially equivalent but not topologically conjugate on their Julia sets. This disproves a conjecture by McMullen from 1995....
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DEFF Research Database (Denmark)
Pedersen, Lise
2015-01-01
University College Lillebaelt has decided that 30 percent of all educational elements must be generated as blended learning by the end of the year 2015 as part of a modernization addressing following educational needs: 1. Blended learning can help match the expectations of the future students who...... learning. 4. Blended learning can contribute to supporting and improving efficiency of educational efforts. This can for instance be done through programmes for several classes by using video conferencing, allocating traditional face to face teaching to synchronous and asynchronous study activities produce...... digital materials which can be employed didactically and reused by the teachers. This can also mean that the particular competencies which teaches have in Svendborg can be used at other locations in UCL and disseminated to a larger group of students without further costs. Educational Innovation...
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Directory of Open Access Journals (Sweden)
Cuong D. Tran
2015-05-01
Full Text Available It is well recognised that zinc deficiency is a major global public health issue, particularly in young children in low-income countries with diarrhoea and environmental enteropathy. Zinc supplementation is regarded as a powerful tool to correct zinc deficiency as well as to treat a variety of physiologic and pathologic conditions. However, the dose and frequency of its use as well as the choice of zinc salt are not clearly defined regardless of whether it is used to treat a disease or correct a nutritional deficiency. We discuss the application of zinc stable isotope tracer techniques to assess zinc physiology, metabolism and homeostasis and how these can address knowledge gaps in zinc supplementation pharmacokinetics. This may help to resolve optimal dose, frequency, length of administration, timing of delivery to food intake and choice of zinc compound. It appears that long-term preventive supplementation can be administered much less frequently than daily but more research needs to be undertaken to better understand how best to intervene with zinc in children at risk of zinc deficiency. Stable isotope techniques, linked with saturation response and compartmental modelling, also have the potential to assist in the continued search for simple markers of zinc status in health, malnutrition and disease.
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Tran, Cuong D.; Gopalsamy, Geetha L.; Mortimer, Elissa K.; Young, Graeme P.
2015-01-01
It is well recognised that zinc deficiency is a major global public health issue, particularly in young children in low-income countries with diarrhoea and environmental enteropathy. Zinc supplementation is regarded as a powerful tool to correct zinc deficiency as well as to treat a variety of physiologic and pathologic conditions. However, the dose and frequency of its use as well as the choice of zinc salt are not clearly defined regardless of whether it is used to treat a disease or correct a nutritional deficiency. We discuss the application of zinc stable isotope tracer techniques to assess zinc physiology, metabolism and homeostasis and how these can address knowledge gaps in zinc supplementation pharmacokinetics. This may help to resolve optimal dose, frequency, length of administration, timing of delivery to food intake and choice of zinc compound. It appears that long-term preventive supplementation can be administered much less frequently than daily but more research needs to be undertaken to better understand how best to intervene with zinc in children at risk of zinc deficiency. Stable isotope techniques, linked with saturation response and compartmental modelling, also have the potential to assist in the continued search for simple markers of zinc status in health, malnutrition and disease. PMID:26035248
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Blended Learning: How Teachers Balance the Blend of Online and Classroom Components
Jeffrey, Lynn M.; Milne, John; Suddaby, Gordon
2014-01-01
Despite teacher resistance to the use of technology in education, blended learning has increased rapidly, driven by evidence of its advantages over either online or classroom teaching alone. However, blended learning courses still fail to maximize the benefits this format offers. Much research has been conducted on various aspects of this problem,…
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Effect of zinc from zinc sulfate on trace mineral concentrations of milk ...
African Journals Online (AJOL)
PRECIOUS
2009-11-16
Nov 16, 2009 ... It suggests that supplementation of ewes diet with zinc sulfate could be an effective way to increase zinc ... alkaline phosphates activity. Zinc supplements were .... Similar results have been reported previously when dairy cows.
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Generalized Born-Infeld actions and projective cubic curves
Energy Technology Data Exchange (ETDEWEB)
Ferrara, S. [Department of Physics, CERN Theory Division, CH - 1211 Geneva 23 (Switzerland); INFN - Laboratori Nazionali di Frascati, Via Enrico Fermi 40, I-00044, Frascati (Italy); Porrati, M. [CCPP, Department of Physics, NYU, 4 Washington Pl., New York, NY, 10003 (United States); Sagnotti, A. [Department of Physics, CERN Theory Division, CH - 1211 Geneva 23 (Switzerland); Stora, R. [Department of Physics, CERN Theory Division, CH - 1211 Geneva 23 (Switzerland); Laboratoire d' Annecy-le-Vieux de Physique Theorique (LAPTH), F-74941, Annecy-le-Vieux, Cedex (France); Yeranyan, A. [INFN - Laboratori Nazionali di Frascati, Via Enrico Fermi 40, I-00044, Frascati (Italy); Centro Studi e Ricerche Enrico Fermi, Via Panisperna 89A, 00184, Roma (Italy)
2015-04-01
We investigate U(1){sup n} supersymmetric Born-Infeld Lagrangians with a second non-linearly realized supersymmetry. The resulting non-linear structure is more complex than the square root present in the standard Born-Infeld action, and nonetheless the quadratic constraints determining these models can be solved exactly in all cases containing three vector multiplets. The corresponding models are classified by cubic holomorphic prepotentials. Their symmetry structures are associated to projective cubic varieties. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
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International Nuclear Information System (INIS)
Paun, Irina Alexandra; Ion, Valentin; Moldovan, Antoniu; Dinescu, Maria
2011-01-01
In this work, we show successful use of matrix-assisted pulsed laser evaporation (MAPLE) for obtaining thin films of PEG:PLGA blends, in the view of their use for controlled drug delivery. In particular, we investigate the influence of the blending ratios on the characteristics of the films. We show that the roughness of the polymeric films is affected by the ratio of each polymer within the blend. In addition, we perform Fourier transformed infrared spectroscopy (FTIR) measurements and we find that the intensities ratios of the infrared absorption bands of the two polymers are consistent with the blending ratios. Finally, we assess the optical constants of the polymeric films by spectroscopic ellipsometry (SE). We point out that the blending ratios exert an influence on the optical characteristics of the films and we validate the SE results by atomic force microscopy and UV-vis spectrophotometry. In all, we stress that the ratios in which the two polymers are blended have significant impact on the morphology, chemical structure and optical characteristics of the polymeric films deposited by MAPLE.
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Studies on the synthesis of cubic ZnS quantum dots, capping and optical–electrical characteristics
International Nuclear Information System (INIS)
Saravanan, R. Sakthi Sudar; Pukazhselvan, D.; Mahadevan, C.K.
2012-01-01
Highlights: ► Zinc acetate and sodium sulphide as reactants. Cubic QDs of size ∼3 nm in 1:3 reactant ratios with or without capping agent. ► At least 30 times smaller size while using microwave source instead of conventional heating source. ► Widening of band gap from 3.6 eV to 3.94 eV by reducing size of ZnS. ► Better conduction with lower activation energy in wide band gap ZnS. ► Thermionic emission mechanism for conduction phenomenon. - Abstract: This paper presents a comparative analysis of ZnS QDs synthesized by conventional and microwave heating techniques using zinc acetate and sodium sulphide reactants. The size of the quantum dots achieved by the latter technique (∼3 nm) is at least 30 times smaller than the former technique. Incorporation of excess Na 2 S and microwave treatment are the important factors responsible for controlling the size of ZnS nanocrystals. Furthermore, the distribution of quantum dots is highly influenced by the addition of small amount of NaOH. The UV–vis analysis reveals that the band gap can be widened up to 3.94 eV (correspond to ∼3 nm ZnS) from 3.67 eV (correspond to bulk ZnS). Surprisingly better conductivity is observed for the widest band gap ZnS of the present study; this could be due to defects/vacancies present in the system and its influence in the band structure. The higher conductivity value is supported by the smaller activation energy value, smaller dielectric constant and higher dielectric loss, etc. The conduction is further explained by thermionic emission mechanism.
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International Nuclear Information System (INIS)
Dacal, Luis C O; Cantarero, A
2014-01-01
Most III–V semiconductors, which acquire the zinc-blende phase as bulk materials, adopt the metastable wurtzite phase when grown in the form of nanowires. These are new semiconductors with new optical properties, in particular, a different electronic band gap when compared with that grown in the zinc-blende phase. The electronic gap of wurtzite InAs at the Γ–point of the Brillouin zone (E 0 gap) has been recently measured, E 0 =0.46 eV at low temperature. The electronic gap at the A–point of the Brillouin zone (equivalent to the L–point in the zinc-blende structure, E 1 ) has also been obtained recently based on a resonant Raman scattering experiment. In this work, we calculate the band structure of InAs in the zinc-blende and wurtzite phases, using the full potential linearized augmented plane wave method, including spin-orbit interaction. The electronic band gap has been improved through the modified Becke–Johnson exchange-correlation potential. Both the E 0 and E 1 gaps agree very well with the experiment. From the calculations, a crystal field splitting of 0.122 eV and a spin-orbit splitting of 0.312 eV (the experimental value in zinc-blende InAs is 0.4 eV) has been obtained. Finally, we calculate the dielectric function of InAs in both the zinc-blende and wurtzite phases and a comparative discussion is given. (paper)
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Dacal, Luis C. O.; Cantarero, A.
2014-03-01
Most III-V semiconductors, which acquire the zinc-blende phase as bulk materials, adopt the metastable wurtzite phase when grown in the form of nanowires. These are new semiconductors with new optical properties, in particular, a different electronic band gap when compared with that grown in the zinc-blende phase. The electronic gap of wurtzite InAs at the \\Gamma -point of the Brillouin zone ({{E}_{0}} gap) has been recently measured, {{E}_{0}}=0.46 eV at low temperature. The electronic gap at the A-point of the Brillouin zone (equivalent to the L-point in the zinc-blende structure, {{E}_{1}}) has also been obtained recently based on a resonant Raman scattering experiment. In this work, we calculate the band structure of InAs in the zinc-blende and wurtzite phases, using the full potential linearized augmented plane wave method, including spin-orbit interaction. The electronic band gap has been improved through the modified Becke-Johnson exchange-correlation potential. Both the {{E}_{0}} and {{E}_{1}} gaps agree very well with the experiment. From the calculations, a crystal field splitting of 0.122 eV and a spin-orbit splitting of 0.312 eV (the experimental value in zinc-blende InAs is 0.4 eV) has been obtained. Finally, we calculate the dielectric function of InAs in both the zinc-blende and wurtzite phases and a comparative discussion is given.
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Emissions characteristics of higher alcohol/gasoline blends
International Nuclear Information System (INIS)
Gautam, M.; Martin, D.W.; Carder, D.
2000-01-01
An experimental investigation was conducted to determine the emissions characteristics of higher alcohols and gasoline (UTG96) blends. While lower alcohols (methanol and ethanol) have been used in blends with gasoline, very little work has been done or reported on higher alcohols (propanol, butanol and pentanol). Comparisons of emissions and fuel characteristics between higher alcohol/gasoline blends and neat gasoline were made to determine the advantages and disadvantages of blending higher alcohols with gasoline. All tests were conducted on a single-cylinder Waukesha Cooperative Fuel Research engine operating at steady state conditions and stoichiometric air-fuel (A/F) ratio. Emissions test were conducted at the optimum spark timing-knock limiting compression ratio combination for the particular blend being tested. The cycle emission [mass per unit time (g/h)] of CO, CO 2 and organic matter hydrocarbon equivalent (OMHCE) from the higher alcohol/gasoline blends were very similar to those from neat gasoline. Cycle emissions of NO x from the blends were higher than those from neat gasoline. However, for all the emissions species considered, the brake specific emissions (g/kW h) were significantly lower for the higher alcohol/gasoline blends than for neat gasoline. This was because the blends had greater resistance to knock and allowed higher compression ratios, which increased engine power output. The contribution of alcohols and aldehydes to the overall OMHCE emissions was found to be minimal. Cycle fuel consumption (g/h) of higher alcohol/gasoline blends was slightly higher than with neat gasoline due to the lower stoichiometric A/F ratios required by the blends. However, the brake specific fuel consumption (g/kW h) for the blends was significantly lower than that for neat gasoline. (Author)
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Evolution of the zinc compound nanostructures in zinc acetate single-source solution
International Nuclear Information System (INIS)
Wang Ying; Li Yinhua; Zhou Zhengzhi; Zu Xihong; Deng Yulin
2011-01-01
A series of nanostructured zinc compounds with different nanostructures such as nanobelts, flake-like, flower-like, and twinning crystals was synthesized using zinc acetate (Zn(Ac) 2 ) as a single-source. The evolution of the zinc compounds from layered basic zinc acetate (LBZA) to bilayered basic zinc acetate (BLBZA) and twinned ZnO nano/microcrystal was studied. The low-angle X-ray diffraction spectra indicate the layered spacing is 1.34 and 2.1 nm for LBZA and BLBZA, respectively. The Fourier transform infrared (FTIR) spectra results confirmed that the bonding force of acetate anion with zinc cations decreases with the phase transformation from Zn(Ac) 2 to BLBZA, and finally to LBZA. The OH − groups gradually replaced the acetate groups coordinated to the matrix zinc cation, and the acetate groups were released completely. Finally, the Zn(OH) 2 and ZnO were formed at high temperature. The conversion process from Zn(Ac) 2 to ZnO with release of acetate anions can be described as Zn(Ac) 2 → BLBZA → LBZA → Zn(OH) 2 → ZnO.
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Fukahori, M; Itoh, M
1990-10-08
The effects of dietary zinc status on the development of convulsive seizures, and zinc concentrations in discrete hippocampal areas and other parts of the limbic system were studied in the El mouse model receiving zinc-adequate, zinc-deficient or zinc-loaded diets. Seizure susceptibility of the El mouse was increased by zinc deficiency, and decreased by zinc loading, while an adequate diet had no effect. Zinc loading was accompanied by a marked increase in hippocampal zinc content in the El mouse. Conversely, hippocampal zinc content declined in the El mouse fed a zinc-deficient diet. These results suggest that zinc may have a preventive effect on the development of seizures in the El mouse, and hippocampal zinc may play an important role in the pathophysiology of convulsive seizures of epilepsy.
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International Nuclear Information System (INIS)
Johnson, W.T.; Canfield, W.K.
1985-01-01
65 Zn was used to examine the effects of dietary zinc and protein on true zinc absorption and intestinal excretion of endogenous zinc by an isotope dilution technique in streptozotocin-diabetic and control rats. Four groups each of diabetic and control rats were fed diets containing 20 ppm Zn, 20% egg white protein (HMHP); 20 ppm Zn, 10% egg white protein (HMLP); 10 ppm Zn, 20% egg white protein (LMHP); and 10 ppm Zn, 10% egg white protein (LMLP). Measurement of zinc balance was begun 9 d after an i.m. injection of 65 Zn. True zinc absorption and the contribution of endogenous zinc to fecal zinc excretion were calculated from the isotopically labeled and unlabeled zinc in the feces, duodenum and kidney. Results from the isotope dilution study indicated that diabetic rats, but not control rats, absorbed more zinc from 20 ppm zinc diets than from 10ppm zinc diets and that all rats absorbed more zinc from 20% protein diets than from 10% protein diets. Furthermore, all rats excreted more endogenous zinc from their intestines when dietary zinc and protein levels resulted in greater zinc absorption. In diabetic and control rats, consuming equivalent amounts of zinc, the amount of zinc absorbed was not significantly different, but the amount of zinc excreted by the intestine was less in the diabetic rats. Decreased intestinal excretion of endogenous zinc may be a homeostatic response to the increased urinary excretion of endogenous zinc in the diabetic rats and may also lead to the elevated zinc concentrations observed in some organs of the diabetic rats
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40 CFR 80.82 - Butane blending.
2010-07-01
... FUELS AND FUEL ADDITIVES Reformulated Gasoline § 80.82 Butane blending. A refiner for any refinery that produces gasoline by blending butane with conventional gasoline or reformulated gasoline or RBOB may meet... paragraph (b)(1) of this section, the refiner may: (i) Blend the butane with conventional gasoline, or...
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Development of high-performance blended cements
Wu, Zichao
2000-10-01
This thesis presents the development of high-performance blended cements from industrial by-products. To overcome the low-early strength of blended cements, several chemicals were studied as the activators for cement hydration. Sodium sulfate was discovered as the best activator. The blending proportions were optimized by Taguchi experimental design. The optimized blended cements containing up to 80% fly ash performed better than Type I cement in strength development and durability. Maintaining a constant cement content, concrete produced from the optimized blended cements had equal or higher strength and higher durability than that produced from Type I cement alone. The key for the activation mechanism was the reaction between added SO4 2- and Ca2+ dissolved from cement hydration products.
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Chelators for investigating zinc metalloneurochemistry
Radford, Robert John; Lippard, Stephen J.
2013-01-01
The physiology and pathology of mobile zinc signaling has become an important topic in metalloneurochemistry. To study the action of mobile zinc effectively, specialized tools are required that probe the temporal and positional changes of zinc ions within live tissue and cells. In the present article we describe the design and implementation of selective zinc chelators as antagonists to interrogate the function of mobile zinc, with an emphasis on the pools of vesicular zinc in the terminals o...
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Energy Technology Data Exchange (ETDEWEB)
Muthukumarasamy, N. [Department of Physics, Coimbatore Institute of Technology, Coimbatore, Tamilnadu (India); Jayakumar, S.; Kannan, M.D.; Balasundaraprabhu, R. [Thin Film Center, PSG College of Technology, Coimbatore, Tamilnadu (India)
2009-04-15
CdSe{sub x}Te{sub 1-x} thin films of different compositions have been deposited on glass substrates by hot wall deposition method under conditions very close to thermodynamical equilibrium with minimum loss of material. The structural studies carried out on the deposited films revealed that they are crystalline in nature and exhibit either cubic zinc blende or hexagonal phase or both depending on the composition of the material. The lattice parameter values for both cubic and hexagonal phases have been determined and are observed to vary with composition according to Vegard's law. The optical properties of the deposited CdSe{sub x}Te{sub 1-x} thin films have been studied using transmittance spectra. The spectra shows a sharp fall in transmittance at wavelength corresponding to the band gap of the material. The optical band gap has been determined and found to be direct allowed. The band gap has been observed to strongly depend on film composition. The variation of band gap with composition has been observed to be quadratic in nature exhibiting a bowing behaviour. (author)
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Some elements go cubic under pressure
Czech Academy of Sciences Publication Activity Database
Legut, Dominik
2007-01-01
Roč. 60, č. 10 (2007), s. 17-17 ISSN 0031-9228 Institutional research plan: CEZ:AV0Z20410507 Keywords : ab initio * polonium * cubic structure Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 5.133, year: 2007
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Zinc and gastrointestinal disease
Institute of Scientific and Technical Information of China (English)
Sonja; Skrovanek; Katherine; DiGuilio; Robert; Bailey; William; Huntington; Ryan; Urbas; Barani; Mayilvaganan; Giancarlo; Mercogliano; James; M; Mullin
2014-01-01
This review is a current summary of the role that both zinc deficiency and zinc supplementation can play in the etiology and therapy of a wide range of gastrointestinal diseases. The recent literature describing zinc action on gastrointestinal epithelial tight junctions and epithelial barrier function is described. Zinc enhancement of gastrointestinal epithelial barrier function may figure prominently in its potential therapeutic action in several gastrointestinal diseases.
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THE COMBUSTION CHARACTERISTICS OF LIGNITE BLENDS
Institute of Scientific and Technical Information of China (English)
Cheng Jun; Zhou Junhu; Cao Xinyu; Cen Kefa
2000-01-01
The combustion characteristics of lignite blends were studied with a thermogravimetric analyzer (t.g.a.), at constant heating rate.The characteristic temperatures were determined from the burning profiles.It was found that the characteristic times of combustion reaction moved forward, the ignition temperature dropped and the burnout efficiency slightly changed when blending lignites.The characteristic parameters of blends could not be predicted as a linear function of the average values of the individual lignites.when blending with less reactive coal, the ignition and burnout characteristics of lignite turned worse.
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Trace spaces in a pre-cubical complex
DEFF Research Database (Denmark)
Raussen, Martin
2009-01-01
In directed algebraic topology, directed irreversible (d)-paths and spaces consisting of d-paths are studied from a topological and from a categorical point of view. Motivated by models for concurrent computation, we study in this paper spaces of d-paths in a pre-cubical complex. Such paths...... are equipped with a natural arc length which moreover is shown to be invariant under directed homotopies. D-paths up to reparametrization (called traces) can thus be represented by arc length parametrized d-paths. Under weak additional conditions, it is shown that trace spaces in a pre-cubical complex...... are separable metric spaces which are locally contractible and locally compact. Moreover, they have the homotopy type of a CW-complex....
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Zinc species distribution in EDTA-extract residues of zinc-contaminated soil
International Nuclear Information System (INIS)
Chang, S.-H.; Wei, Y.-L.; Wang, H. Paul
2007-01-01
Soil sample from a site heavily contaminated with >10 wt.% zinc is sampled and extracted with aqueous solutions of ethylene diamine tetra-acetic acid (EDTA) that is a reagent frequently used to extract heavy metals in soil remediation. Three liquid/soil ratios (5/1, 20/1, and 100/1) were used in the extracting experiment. The molecular environment of the residual Zn in the EDTA-extract residues of zinc-contaminated soil is investigated with XANES technique. The results indicate that EDTA does not show considerable preference of chelating for any particular Zn species during the extraction. Zn species distribution in the sampled soil is found to resemble that in all EDTA-extract residues; Zn(OH) 2 is determined as the major zinc species (60-70%), seconded by organic zinc (21-26%) and zinc oxide (9-14%)
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International Nuclear Information System (INIS)
Passador, Fabio R.; Ruvolo Filho, Adhemar; Pessan, Luiz A.
2011-01-01
The blending sequence affects the morphology formation of the nanocomposites. In this work, the blending sequences were explored to determine its influence in the rheological behavior of HDPE/LLDPE/OMMT nanocomposites. The nanocomposites were obtained by melt-intercalation using a mixture of LLDPE-g-MA and HDPE-g-MA as compatibilizer system in a torque rheometer at 180 deg C and five blending sequences were studied. The materials structures were characterized by wide angle X-ray diffraction (WAXD) and by rheological properties. The nanoclay's addition increased the shear viscosity at low shear rates, changing the behavior of HDPE/LLDPE matrix to a Bingham model behavior with an apparent yield stress. Intense interactions were obtained for the blending sequence where LLDPE and/or LLDPE-g-MA were first reinforced with organoclay since the intercalation process occurs preferentially in the amorphous phase. (author)
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Innovative uses for zinc in dermatology.
Bae, Yoon Soo; Hill, Nikki D; Bibi, Yuval; Dreiher, Jacob; Cohen, Arnon D
2010-07-01
Severe zinc deficiency states, such as acrodermatitis enteropathica, are associated with a variety of skin manifestations, such as perioral, acral, and perineal dermatitis. These syndromes can be reversed with systemic zinc repletion. In addition to skin pathologies that are clearly zinc-dependent, many dermatologic conditions (eg, dandruff, acne, and diaper rash) have been associated and treated with zinc. Success rates for treatment with zinc vary greatly depending on the disease, mode of administration, and precise zinc preparation used. With the exception of systemic zinc deficiency states, there is little evidence that convincingly demonstrates the efficacy of zinc as a reliable first-line treatment for most dermatologic conditions. However, zinc may be considered as an adjunctive treatment modality. Further research is needed to establish the indications for zinc treatment in dermatology, optimal mode of zinc delivery, and best type of zinc compound to be used. Copyright 2010 Elsevier Inc. All rights reserved.
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Energy Technology Data Exchange (ETDEWEB)
Onwudiwe, Damian C., E-mail: dconwudiwe@webmail.co.za [Chemical Resource Beneficiation, North-West University, Private Bag X6001, Potchefstroom 2520 (South Africa); Strydom, Christien [Chemical Resource Beneficiation, North-West University, Private Bag X6001, Potchefstroom 2520 (South Africa); Oluwafemi, Oluwatobi S., E-mail: oluwafemi.oluwatobi@gmail.com [Department of Chemistry and Chemical Technology, Walter Sisulu University, Mthatha Campus, Private Bag X1, Mthatha (South Africa); Songca, Sandile P. [Faculty of Science, Engineering and Technology, Walter Sisulu University, P.O. Box 19712, Tecoma, East London (South Africa)
2012-12-15
Graphical abstract: Display Omitted Highlights: ► HDA-capped ZnS nanoparticles were synthesized via thermolysis of a single source precursor. ► Zinc(II) N-ethyl-N-phenyldithiocarbamate was used as the single source precursor. ► The growth temperature was varied to study the optical properties of the nanocrystals. ► Change in growth temperature affects the structural properties of the ZnS nanoparticles. ► Hexagonal wurtzite phase was obtained at lower temperatures while cubic sphalerite phase was obtained at higher growth temperatures. -- Abstract: Reported in this work is the synthesis of HDA (hexadecylamine)-capped ZnS nanoparticles by a single source route using Zinc(II) N-ethyl-N-phenyldithiocarbamate as a precursor. By varying the growth temperature, the temporal evolution of the optical properties and morphology of the nanocrystals were investigated. The as-synthesized nanoparticles were characterized using UV–vis absorption and photoluminescence (PL) spectroscopy, transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). All the particles exhibited quantum confinement in their optical properties with band edge emission at the early stage of the reaction. The XRD showed transition from hexagonal wurtzite phase to cubic sphalerite phase as the growth temperature increases. The TEM image showed that the particles are small and spherical in shape while the HRTEM image confirmed the crystalline nature of the material.
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To evaluate the influence of resveratrol on cellular zinc status, normal human prostate epithelial (NHPrE) cells were treated with 6 levels of resveratrol (0, 0.5, 1, 2.5, 5 and 10 microM) and 4 levels of zinc [0, 4, 16, and 32 microM for zinc-deficient (ZD), zinc-normal (ZN), zinc-adequate (ZA), an...
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The planar cubic Cayley graphs
Georgakopoulos, Agelos
2018-01-01
The author obtains a complete description of the planar cubic Cayley graphs, providing an explicit presentation and embedding for each of them. This turns out to be a rich class, comprising several infinite families. He obtains counterexamples to conjectures of Mohar, Bonnington and Watkins. The author's analysis makes the involved graphs accessible to computation, corroborating a conjecture of Droms.
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Sulfidation of zinc plating sludge with Na2S for zinc resource recovery
International Nuclear Information System (INIS)
Kuchar, D.; Fukuta, T.; Onyango, M.S.; Matsuda, H.
2006-01-01
A high amount of zinc disposed in the landfill sites as a mixed-metal plating sludge represents a valuable zinc source. To recover zinc from the plating sludge, a sulfidation treatment is proposed in this study, while it is assumed that ZnS formed could be separated by flotation. The sulfidation treatment was conducted by contacting simulated zinc plating sludge with Na 2 S solution at S 2- to Zn 2+ molar ratio of 1.5 for a period of 1-48 h, while changing the solid to liquid (S:L) ratio from 0.25:50 to 1.00:50. The conversion of zinc compounds to ZnS was determined based on the consumption of sulfide ions. The reaction products formed by the sulfidation of zinc were identified by X-ray diffraction (XRD). As a result, it was found that the conversion of zinc compounds to ZnS increased with an increase in S:L ratio. A maximum conversion of 0.809 was obtained at an S:L ratio of 1.00:50 after 48 h. However, when the zinc sludge treated at S:L ratio of 1.00:50 for 48 h was subjected to XRD analyses, only ZnS was identified in the treated zinc sludge. The result suggested that the rest of zinc sludge remained unreacted inside the agglomerates of ZnS. The formation behavior of ZnS was predicted by Elovich equation, which was found to describe the system satisfactorily indicating the heterogeneous nature of the sludge
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Interaction Between Yeasts and Zinc
Nicola, Raffaele De; Walker, Graeme
Zinc is an essential trace element in biological systems. For example, it acts as a cellular membrane stabiliser, plays a critical role in gene expression and genome modification and activates nearly 300 enzymes, including alcohol dehydrogenase. The present chapter will be focused on the influence of zinc on cell physiology of industrial yeast strains of Saccharomyces cerevisiae, with special regard to the uptake and subsequent utilisation of this metal. Zinc uptake by yeast is metabolism-dependent, with most of the available zinc translocated very quickly into the vacuole. At cell division, zinc is distributed from mother to daughter cells and this effectively lowers the individual cellular zinc concentration, which may become zinc depleted at the onset of the fermentation. Zinc influences yeast fermentative performance and examples will be provided relating to brewing and wine fermentations. Industrial yeasts are subjected to several stresses that may impair fermentation performance. Such stresses may also impact on yeast cell zinc homeostasis. This chapter will discuss the practical implications for the correct management of zinc bioavailability for yeast-based biotechnologies aimed at improving yeast growth, viability, fermentation performance and resistance to environmental stresses
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Growth and properties of low-dimensional III-V semiconductor nanowire heterostructures
Energy Technology Data Exchange (ETDEWEB)
Heiss, Martin
2010-08-25
symmetry from cubic zinc-blende to hexagonal wurtzite structure, while the chemical composition of the material remains constant. The GaAs nanowires synthesized with the Au-free technique can be grown under conditions where a statistical wurtzite/zinc-blende polytypism occurs. A novel method for the direct correlation at the nanoscale of structural and optical properties of single GaAs nanowires is developed in order to characterize the resulting statistically distributed quantum heterostructures. Nanowires consisting of {approx}100% wurtzite and nanowires presenting zinc-blende/wurtzite polytypism are studied by photoluminescence spectroscopy and Transmission Electron Microscopy. The photoluminescence of wurtzite GaAs is found to be consistent with a bulk wurtzite band gap of 1.50 eV, slightly smaller compared to the zinc-blende GaAs band gap. In the polytypic nanowires, it is shown that the regions that are predominantly composed of either zinc-blende or wurtzite phase show photoluminescence emission close to the according bulk band gaps, while regions composed of a non periodic superlattice of wurtzite and zinc-blende phases exhibit a redshift of the photoluminescence spectra as low as 1.455 eV. The dimensions of the quantum heterostructures are correlated with the light emission, allowing us to estimate the band offsets of {delta}E{sub CB}=53{+-}20 meV and {delta}E{sub VB}=76{+-}12 meV between the two crystalline phases. These results are in excellent agreement with recent theoretical band structure calculations. (orig.)
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Iron and zinc concentrations and 59Fe retention in developing fetuses of zinc-deficient rats
International Nuclear Information System (INIS)
Rogers, J.M.; Loennerdal, B.H.; Hurley, L.S.; Keen, C.L.
1987-01-01
Because disturbances in iron metabolism might contribute to the teratogenicity of zinc deficiency, we examined the effect of zinc deficiency on fetal iron accumulation and maternal and fetal retention of 59 Fe. Pregnant rats were fed from mating a purified diet containing 0.5, 4.5 or 100 micrograms Zn/g. Laparotomies were performed on d 12, 16, 19 and 21 of gestation. Maternal blood and concepti were analyzed for zinc and iron. Additional groups of dams fed 0.5 or 100 micrograms Zn/g diet were gavaged on d 19 with a diet containing 59 Fe. Six hours later maternal blood and tissues, fetuses and placentas were counted for 59 Fe. Maternal plasma zinc, but not iron, concentration was affected by zinc deficiency on d 12. Embryo zinc concentration on d 12 increased with increasing maternal dietary zinc, whereas iron concentration was not different among groups. On d 16-21 plasma iron was higher in dams fed 0.5 micrograms Zn/g diet than in those fed 4.5 or 100 micrograms/g, whereas plasma zinc was lower in dams fed 0.5 or 4.5 micrograms Zn/g than in those fed 100 micrograms Zn/g diet. On d 19 zinc concentration in fetuses from dams fed 0.5 micrograms/g zinc was not different from that of those fed 4.5 micrograms/g zinc, and iron concentration was higher in the 0.5 microgram Zn/g diet group. The increase in iron concentration in zinc-deficient fetuses thus occurs too late to be involved in major structural teratogenesis. Although whole blood concentration of 59 Fe was not different in zinc-deficient and control dams, zinc-deficient dams had more 59 Fe in the plasma fraction
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Chloroquine is a zinc ionophore.
Directory of Open Access Journals (Sweden)
Jing Xue
Full Text Available Chloroquine is an established antimalarial agent that has been recently tested in clinical trials for its anticancer activity. The favorable effect of chloroquine appears to be due to its ability to sensitize cancerous cells to chemotherapy, radiation therapy, and induce apoptosis. The present study investigated the interaction of zinc ions with chloroquine in a human ovarian cancer cell line (A2780. Chloroquine enhanced zinc uptake by A2780 cells in a concentration-dependent manner, as assayed using a fluorescent zinc probe. This enhancement was attenuated by TPEN, a high affinity metal-binding compound, indicating the specificity of the zinc uptake. Furthermore, addition of copper or iron ions had no effect on chloroquine-induced zinc uptake. Fluorescent microscopic examination of intracellular zinc distribution demonstrated that free zinc ions are more concentrated in the lysosomes after addition of chloroquine, which is consistent with previous reports showing that chloroquine inhibits lysosome function. The combination of chloroquine with zinc enhanced chloroquine's cytotoxicity and induced apoptosis in A2780 cells. Thus chloroquine is a zinc ionophore, a property that may contribute to chloroquine's anticancer activity.
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Effects of quadratic and cubic nonlinearities on a perfectly tuned parametric amplifier
DEFF Research Database (Denmark)
Neumeyer, Stefan; Sorokin, Vladislav; Thomsen, Jon Juel
2016-01-01
We consider the performance of a parametric amplifier with perfect tuning (two-to-one ratio between the parametric and direct excitation frequencies) and quadratic and cubic nonlinearities. A forced Duffing–Mathieu equation with appended quadratic nonlinearity is considered as the model system......, and approximate analytical steady-state solutions and corresponding stabilities are obtained by the method of varying amplitudes. Some general effects of pure quadratic, and mixed quadratic and cubic nonlinearities on parametric amplification are shown. In particular, the effects of mixed quadratic and cubic...... nonlinearities may generate additional amplitude–frequency solutions. In this case an increased response and a more phase sensitive amplitude (phase between excitation frequencies) is obtained, as compared to the case with either pure quadratic or cubic nonlinearity. Furthermore, jumps and bi...
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Wang, X X; Zhang, M J; Li, X B
2018-01-20
Zinc is one of the essential trace elements in human body, which plays an important role in regulating acute inflammatory response, glucose metabolism, anti-oxidation, immune and gastrointestinal function of patients with severe burns. Patients with severe burns may suffer from zinc deficiency because of insufficient amount of zinc intake from the diet and a large amount of zinc lose through wounds and urine. Zinc deficiency may affect their wound healing process and prognosis. This article reviews the characteristics of zinc metabolism in patients with severe burns through dynamic monitoring the plasma and urinary concentration of zinc. An adequate dosage of zinc supplemented to patients with severe burns by an appropriate method can increase the level of zinc in plasma and skin tissue and improve wound healing, as well as reduce the infection rates and mortality. At the same time, it is important to observe the symptoms and signs of nausea, dizziness, leukopenia and arrhythmia in patients with severe burns after supplementing excessive zinc.
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[Multimodal medical image registration using cubic spline interpolation method].
He, Yuanlie; Tian, Lianfang; Chen, Ping; Wang, Lifei; Ye, Guangchun; Mao, Zongyuan
2007-12-01
Based on the characteristic of the PET-CT multimodal image series, a novel image registration and fusion method is proposed, in which the cubic spline interpolation method is applied to realize the interpolation of PET-CT image series, then registration is carried out by using mutual information algorithm and finally the improved principal component analysis method is used for the fusion of PET-CT multimodal images to enhance the visual effect of PET image, thus satisfied registration and fusion results are obtained. The cubic spline interpolation method is used for reconstruction to restore the missed information between image slices, which can compensate for the shortage of previous registration methods, improve the accuracy of the registration, and make the fused multimodal images more similar to the real image. Finally, the cubic spline interpolation method has been successfully applied in developing 3D-CRT (3D Conformal Radiation Therapy) system.
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Regularizing cubic open Neveu-Schwarz string field theory
International Nuclear Information System (INIS)
Berkovits, Nathan; Siegel, Warren
2009-01-01
After introducing non-minimal variables, the midpoint insertion of Y Y-bar in cubic open Neveu-Schwarz string field theory can be replaced with an operator N ρ depending on a constant parameter ρ. As in cubic open superstring field theory using the pure spinor formalism, the operator N ρ is invertible and is equal to 1 up to a BRST-trivial quantity. So unlike the linearized equation of motion Y Y-bar QV = 0 which requires truncation of the Hilbert space in order to imply QV = 0, the linearized equation N ρ QV = 0 directly implies QV = 0.
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Dian, Linghui; Yang, Zhiwen; Li, Feng; Wang, Zhouhua; Pan, Xin; Peng, Xinsheng; Huang, Xintian; Guo, Zhefei; Quan, Guilan; Shi, Xuan; Chen, Bao; Li, Ge; Wu, Chuanbin
2013-01-01
In order to improve the oral bioavailability of ibuprofen, ibuprofen-loaded cubic nanoparticles were prepared as a delivery system for aqueous formulations. The cubic inner structure was verified by cryogenic transmission electron microscopy. With an encapsulation efficiency greater than 85%, the ibuprofen-loaded cubic nanoparticles had a narrow size distribution around a mean size of 238 nm. Differential scanning calorimetry and X-ray diffraction determined that ibuprofen was in an amorphous and molecular form within the lipid matrix. The in vitro release of ibuprofen from cubic nanoparticles was greater than 80% at 24 hours, showing sustained characteristics. The pharmacokinetic study in beagle dogs showed improved absorption of ibuprofen from cubic nanoparticles compared to that of pure ibuprofen, with evidence of a longer half-life and a relative oral bioavailability of 222% (P ibuprofen-loaded cubic nanoparticles provide a promising carrier candidate with an efficient drug delivery for therapeutic treatment. PMID:23468008
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Polyethylene/hydrophilic polymer blends for biomedical applications.
Brynda, E; Houska, M; Novikova, S P; Dobrova, N B
1987-01-01
Polyethylene blends with poly(2-hydroxyethyl methacrylate) [poly(HEMA)] or poly(2,3-dihydroxypropyl methacrylate) [poly(DHPMA)] were prepared by swelling polyethylene with HEMA or 2,3-epoxypropyl methacrylate (EPMA) and by polymerization of the respective monomers. Poly(EPMA) in blends was hydrolysed to poly(DHPMA) with acetic acid. The blends had similar surface and bulk compositions. Swelling with water and surface wettability were proportional to the content of the hydrophilic component; at the same content the polyethylene/poly(DHPMA) blends appeared more hydrophilic than those of polyethylene/poly(HEMA). Thrombus formation in contact with blood examined ex vivo and in vivo was considerably slower on the blends than on unmodified polyethylene. The tests indicated optima in composition; the best biological response was achieved with the blends containing about 14% poly(HEMA) or 16% poly(DHPMA).
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Energy Technology Data Exchange (ETDEWEB)
NONE
1995-09-01
US DOE is examining options for disposing of surplus weapons-usable fissile materials and storage of all weapons-usable fissile materials. The nuclear material is converted to a form more proliferation- resistant than the original form. Blending HEU (highly enriched uranium) with less-enriched uranium to form LEU has been proposed as a disposition option. Five technologies are being assessed for blending HEU. This document provides data to be used in environmental impact analysis for the HEU-LEU disposition option that uses metal blending with an oxide waste product. It is divided into: mission and assumptions, conversion and blending facility descriptions, process descriptions and requirements, resource needs, employment needs, waste and emissions from plant, hazards discussion, and intersite transportation.
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International Nuclear Information System (INIS)
1995-09-01
US DOE is examining options for disposing of surplus weapons-usable fissile materials and storage of all weapons-usable fissile materials. The nuclear material is converted to a form more proliferation- resistant than the original form. Blending HEU (highly enriched uranium) with less-enriched uranium to form LEU has been proposed as a disposition option. Five technologies are being assessed for blending HEU. This document provides data to be used in environmental impact analysis for the HEU-LEU disposition option that uses metal blending with an oxide waste product. It is divided into: mission and assumptions, conversion and blending facility descriptions, process descriptions and requirements, resource needs, employment needs, waste and emissions from plant, hazards discussion, and intersite transportation
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Numbers for reducible cubic scrolls
Directory of Open Access Journals (Sweden)
Israel Vainsencher
2004-12-01
Full Text Available We show how to compute the number of reducible cubic scrolls of codimension 2 in (math blackboard symbol Pn incident to the appropriate number of linear spaces.Mostramos como calcular o número de rolos cúbicos redutíveis de codimensão 2 em (math blackboard symbol Pn incidentes a espaços lineares apropriados.
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Luminescence study of ZnSe/PVA (polyvinyl alcohol) composite film
Energy Technology Data Exchange (ETDEWEB)
Lahariya, Vikas [Amity School of Applied Science, Amity University Haryana Panchgaon, Manesar, Haryana 122413 (India)
2016-05-06
The ZnSe nanocrystals have been prepared into poly vinyl alcohol(PVA) polymer matrix on glass using ZnCl2 and Na2SeSO3 as zinc and selenium source respectively. Poly vinyl Alcohol (PVA) used as polymer matrix cum capping agent due to their high viscosity and water solubility. It is transparent for visible region and prevents Se- ions to photo oxidation. The ZnSe/PVA composite film was deposited on glass substrate. The film was characterized by X Ray Diffraction (XRD) and UV-Visible absorption Spectroscopy and Photoluminescence. The X Ray Diffraction (XRD) study confirms the nanometer size (10 nm) particle formation within PVA matrix with cubic zinc blend crystal structure. The UV-Visible Absorption spectrum of ZnSe/PVA composite film shown blue shift in absorption edge indicating increased band gap due to quantum confinement. The calculated energy band gap from the absorption edge using Tauc relation is 3.4 eV. From the Photoluminescence study a broad peak at 435 nm has been observed in violet blue region due to recombination of surface states.
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International Nuclear Information System (INIS)
1995-09-01
The United States Department of Energy (DOE) is examining options for the disposition of surplus weapons-usable fissile materials and storage of all weapons-usable fissile materials. Disposition is a process of use or disposal of material that results in the material being converted to a form that is substantially and inherently more proliferation-resistant than is the original form. Examining options for increasing the proliferation resistance of highly enriched uranium (HEU) is part of this effort. This report provides data to be used in the environmental impact analysis for the uranyl nitrate hexahydrate blending option to produce oxide for disposal. This the Conversion and Blending Facility (CBF) alternative will have two missions (1) convert HEU materials into HEU uranyl nitrate (UNH) and (2) blend the HEU uranyl nitrate with depleted and natural assay uranyl nitrate to produce an oxide that can be stored until an acceptable disposal approach is available. The primary emphasis of this blending operation will be to destroy the weapons capability of large, surplus stockpiles of HEU. The blended LEU product can only be made weapons capable again by the uranium enrichment process. The blended LEU will be produced as a waste suitable for storage or disposal
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Energy Technology Data Exchange (ETDEWEB)
NONE
1995-09-01
The United States Department of Energy (DOE) is examining options for the disposition of surplus weapons-usable fissile materials and storage of all weapons-usable fissile materials. Disposition is a process of use or disposal of material that results in the material being converted to a form that is substantially and inherently more proliferation-resistant than is the original form. Examining options for increasing the proliferation resistance of highly enriched uranium (HEU) is part of this effort. This report provides data to be used in the environmental impact analysis for the uranyl nitrate hexahydrate blending option to produce oxide for disposal. This the Conversion and Blending Facility (CBF) alternative will have two missions (1) convert HEU materials into HEU uranyl nitrate (UNH) and (2) blend the HEU uranyl nitrate with depleted and natural assay uranyl nitrate to produce an oxide that can be stored until an acceptable disposal approach is available. The primary emphasis of this blending operation will be to destroy the weapons capability of large, surplus stockpiles of HEU. The blended LEU product can only be made weapons capable again by the uranium enrichment process. The blended LEU will be produced as a waste suitable for storage or disposal.
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Viscoelastic properties of PLA/PCL blends compatibilized with different methods
Shin, Boo Young; Han, Do Hung
2017-11-01
The aim of this study was to observe changes in the viscoelastic properties of PLA/PCL (80/20) blends produced using different compatibilization methods. Reactive extrusion and high-energy radiation methods were used for blend compatibilization. Storage and loss moduli, complex viscosity, transient stress relaxation modulus, and tan δ of blends were analyzed and blend morphologies were examined. All compatibilized PLA/PCL blends had smaller dispersed particle sizes than the non-compatibilized blend, and well compatibilized blends had finer morphologies than poorly compatibilized blends. Viscoelastic properties differentiated well compatibilized and poorly compatibilized blends. Well compatibilized blends had higher storage and loss moduli and complex viscosities than those calculated by the log-additive mixing rule due to strong interfacial adhesion, whereas poorly compatibilized blends showed negative deviations due to weak interfacial adhesion. Moreover, well compatibilized blends had much slower stress relaxation than poorly compatibilized blends and didn't show tan δ plateau region caused by slippage at the interface between continuous and dispersed phases.
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Zinc bioavailability in the chick
International Nuclear Information System (INIS)
Hempe, J.M.
1987-01-01
Methods for assessing zinc bioavailability were evaluated in the chick. A low-zinc chick diet was developed using rehydrated, spray-dried egg white autoclaved at 121 C for 30 min as the primary protein source. The relative bioavailability of zinc from soy flour and beef was determined by whole-body retention of extrinsic 65 Zn, and in slope ratio assays for growth rate and tissue zinc. Compared to zinc carbonate added to an egg white-based diet, all methods gave similar estimates of approximately 100% zinc bioavailability for beef but estimates for soy flour varied widely. The slope ratio assay for growth rate gave the best estimate of zinc bioavailability for soy flour. True absorption, as measured by percent isotope retention from extrinsically labeled soy flour, was 47%
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First-principles calculations of a high-pressure synthesized compound PtC
International Nuclear Information System (INIS)
Li Linyan; Yu Wen; Jin Changqing
2005-01-01
The first-principles density-functional method is used to study the recently high-pressure synthesized compound PtC. It is confirmed by our calculations that platinum carbide has a zinc-blende ground-state phase at zero pressure and that the rock-salt structure is a high-pressure phase. The theoretical transition pressure from zinc-blende to rock-salt structure is determined to be 52 GPa. Furthermore, our calculation shows the possibility that the PtC experimentally synthesized under high pressure conditions might undergo a transition from rock-salt to zinc-blende structure after a pressure quench to ambient conditions
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Mechanical properties of irradiated rubber-blends
International Nuclear Information System (INIS)
Nasr, G.M.; Madani, M.
2005-01-01
A study has been made on blend ratios of natural rubber (NR) and acrylonitrile butadiene rubber (NBR) that are loaded with general purpose furnace (GPE) carbon black and irradiated at different gamma radiation doses. It was fount that the mechanical properties of such blend are highly affected by γ- irradiation dose and the composition ratios of its constituents. The elongation at break for blends was found to increase slightly with increasing NBR loafing which is mainly due to the stiffness of blending matrix formation between NR and GPF carbon black particles. The hysteresis loss, extension ratio and shape factor have been calculated for the different un-irradiated and irradiated samples
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Zinc and zinc transporters in macrophages and their roles in efferocytosis in COPD.
Directory of Open Access Journals (Sweden)
Rhys Hamon
Full Text Available Our previous studies have shown that nutritional zinc restriction exacerbates airway inflammation accompanied by an increase in caspase-3 activation and an accumulation of apoptotic epithelial cells in the bronchioles of the mice. Normally, apoptotic cells are rapidly cleared by macrophage efferocytosis, limiting any secondary necrosis and inflammation. We therefore hypothesized that zinc deficiency is not only pro-apoptotic but also impairs macrophage efferocytosis. Impaired efferocytic clearance of apoptotic epithelial cells by alveolar macrophages occurs in chronic obstructive pulmonary disease (COPD, cigarette-smoking and other lung inflammatory diseases. We now show that zinc is a factor in impaired macrophage efferocytosis in COPD. Concentrations of zinc were significantly reduced in the supernatant of bronchoalveolar lavage fluid of patients with COPD who were current smokers, compared to healthy controls, smokers or COPD patients not actively smoking. Lavage zinc was positively correlated with AM efferocytosis and there was decreased efferocytosis in macrophages depleted of Zn in vitro by treatment with the membrane-permeable zinc chelator TPEN. Organ and cell Zn homeostasis are mediated by two families of membrane ZIP and ZnT proteins. Macrophages of mice null for ZIP1 had significantly lower intracellular zinc and efferocytosis capability, suggesting ZIP1 may play an important role. We investigated further using the human THP-1 derived macrophage cell line, with and without zinc chelation by TPEN to mimic zinc deficiency. There was no change in ZIP1 mRNA levels by TPEN but a significant 3-fold increase in expression of another influx transporter ZIP2, consistent with a role for ZIP2 in maintaining macrophage Zn levels. Both ZIP1 and ZIP2 proteins were localized to the plasma membrane and cytoplasm in normal human lung alveolar macrophages. We propose that zinc homeostasis in macrophages involves the coordinated action of ZIP1 and ZIP2
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Binary blend Nanoparticles with defined morphology
International Nuclear Information System (INIS)
Ghazy, O.A.H.
2008-01-01
The word blend in linguistics means a word formed from two parts of two words. In polymer science polymer blends means polymer mixtures, a class of materials analogues to the metal alloys. Blending of polymers is a simple and economic way to create new materials meeting specific desired properties. The other alternative is to synthesize such materials eventually facing the organic chemistry design difficulties. The low entropy of mixing polymers makes the process thermodynamically unfavorable, unless there are some specific interactions between the mixed polymers. As a result, in thermal equilibrium typically a phase separation between the blend components takes place. The main challenge facing the blending of polymers is the control of the length scale of the phase separation. One of the most important applications, where the control of the phase separation is crucial for the performance is the organic solar cells. In organic solar cells a blend of an electron donating polymer and electron accepting one is formed. The dimensions of the phase separation between the two polymers should be in the range of the exciton diffusion length [1-3] (in semiconductors, exciton diffusion length is the average distance traveled by the electron-hole pair before recombination). Only under this condition the charge transfer at the interface between the two polymer layers can take place and the solar cell performs efficiently. The thin polymer blend layers for such applications are commonly deposited by spin coating from solution containing both polymers. The morphology of the thin layer prepared in this way is highly influenced by the preparation conditions such as the surface properties of the substrate, the solvent from which the blend was deposited, the temperature, and the annealing temperature [4-9]. Therefore controlling the length scale of phase separation in layers casted or spin coated from solutions is difficult and is a matter of trials and errors. Recently a novel
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Face-to-Face Activities in Blended Learning
DEFF Research Database (Denmark)
Kjærgaard, Annemette
While blended learning combines online and face-to-face teaching, research on blended learning has primarily focused on the role of technology and the opportunities it creates for engaging students. Less focus has been put on face-to-face activities in blended learning. This paper argues...... that it is not only the online activities in blended learning that provide new opportunities for rethinking pedagogy in higher education, it is also imperative to reconsider the face-to-face activities when part of the learning is provided online. Based on a review of blended learning in business and management...... education, we identify what forms of teaching and learning are suggested to take place face-to-face when other activities are moved online. We draw from the Community of Inquiry framework to analyze how face-to-face activities contribute to a blended learning pedagogy and discuss the implications...
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BLENDED LEARNING STRATEGY IN TEACHER TRAINING PROGRAMS
Directory of Open Access Journals (Sweden)
Marian F. Byrka
2017-12-01
Full Text Available The article examines the implementation of blended learning strategy in teacher training programs as an innovation in online learning. The blended learning idea comes from blending elements which use online technology with more traditional face-to-face teaching in the same course. The article analyses teacher training programs offered by Chernivtsi Regional Institute of Postgraduate Pedagogical Education. Additional data were gathered through a questionnaire administered to teachers who attended training courses. The characteristics of blended learning strategy, its benefits and limitations for teacher training are supported by a review of literature. The article closes with the comparison of curriculum components (content delivery, learner activities, materials, and required competences between traditional and blended learning teacher training programs. Having obvious benefits in teacher training programs, the implementation of blended learning strategy sets some additional requirements to a learner, as well as to course instructors and lectors.
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Modeling the dispersion of atmospheric pollution using cubic splines and chapeau functions
Energy Technology Data Exchange (ETDEWEB)
Pepper, D W; Kern, C D; Long, P E
1979-01-01
Two methods that can be used to solve complex, three-dimensional, advection-diffusion transport equations are investigated. A quasi-Lagrangian cubic spline method and a chapeau function method are compared in advecting a passive scalar. The methods are simple to use, computationally fast, and reasonably accurate. Little numerical dissipation is manifested by the schemes. In simple advection tests with equal mesh spacing, the chapeau function method maintains slightly more accurate peak values than the cubic spline method. In tests with unequal mesh spacing, the cubic spline method has less noise, but slightly more damping than the standard chapeau method has. Both cubic splines and chapeau functions can be used to solve the three-dimensional problem of gaseous emissions dispersion without excessive programing complexity or storage requirements. (10 diagrams, 39 references, 2 tables)
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Unified treatment of coupled optical and acoustic phonons in piezoelectric cubic materials
DEFF Research Database (Denmark)
Willatzen, Morten; Wang, Zhong Lin
2015-01-01
A unified treatment of coupled optical and acoustic phonons in piezoelectric cubic materials is presented whereby the lattice displacement vector and the internal ionic displacement vector are found simultaneously. It is shown that phonon couplings exist in pairs only; either between the electric...... piezoelectricity in a cubic structured material slab. First, it is shown that isolated optical phonon modes generally cannot exist in piezoelectric cubic slabs. Second, we prove that confined acousto-optical phonon modes only exist for a discrete set of in-plane wave numbers in piezoelectric cubic slabs. Third...... potential and the lattice displacement coordinate perpendicular to the phonon wave vector or between the two other lattice displacement components. The former leads to coupled acousto-optical phonons by virtue of the piezoelectric effect. We then establish three new conjectures that entirely stem from...
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Bioavailability of Zinc in Wistar Rats Fed with Rice Fortified with Zinc Oxide
Della Lucia, Ceres Mattos; Santos, Laura Luiza Menezes; Rodrigues, Kellen Cristina da Cruz; Rodrigues, Vivian Cristina da Cruz; Martino, Hércia Stampini Duarte; Pinheiro Sant’Ana, Helena Maria
2014-01-01
The study of zinc bioavailability in foods is important because this mineral intake does not meet the recommended doses for some population groups. Also, the presence of dietary factors that reduce zinc absorption contributes to its deficiency. Rice fortified with micronutrients (Ultra Rice®) is a viable alternative for fortification since this cereal is already inserted into the population habit. The aim of this study was to evaluate the bioavailability of zinc (Zn) in rice fortified with zinc oxide. During 42 days, rats were divided into four groups and fed with diets containing two different sources of Zn (test diet: UR® fortified with zinc oxide, or control diet: zinc carbonate (ZnCO3)), supplying 50% or 100%, respectively, of the recommendations of this mineral for animals. Weight gain, food intake, feed efficiency ratio, weight, thickness and length of femur; retention of zinc, calcium (Ca) and magnesium (Mg) in the femur and the concentrations of Zn in femur, plasma and erythrocytes were evaluated. Control diet showed higher weight gain, feed efficiency ratio, retention of Zn and Zn concentration in the femur (p 0.05) for dietary intake, length and thickness of the femur, erythrocyte and plasmatic Zn between groups. Although rice fortified with zinc oxide showed a lower bioavailability compared to ZnCO3, this food can be a viable alternative to be used as a vehicle for fortification. PMID:24932657
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27 CFR 24.213 - Heavy bodied blending wine.
2010-04-01
... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Heavy bodied blending wine..., DEPARTMENT OF THE TREASURY LIQUORS WINE Production of Other Than Standard Wine § 24.213 Heavy bodied blending wine. Heavy bodied blending wine is wine made for blending purposes from grapes or other fruit without...
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Directory of Open Access Journals (Sweden)
Karen Lim
2015-04-01
Full Text Available Iron and zinc are found in similar foods and absorption of both may be affected by food compounds, thus biochemical iron and zinc status may be related. This cross-sectional study aimed to: (1 describe dietary intakes and biochemical status of iron and zinc; (2 investigate associations between dietary iron and zinc intakes; and (3 investigate associations between biochemical iron and zinc status in a sample of premenopausal women aged 18–50 years who were recruited in Melbourne and Sydney, Australia. Usual dietary intakes were assessed using a 154-item food frequency questionnaire (n = 379. Iron status was assessed using serum ferritin and hemoglobin, zinc status using serum zinc (standardized to 08:00 collection, and presence of infection/inflammation using C-reactive protein (n = 326. Associations were explored using multiple regression and logistic regression. Mean (SD iron and zinc intakes were 10.5 (3.5 mg/day and 9.3 (3.8 mg/day, respectively. Median (interquartile range serum ferritin was 22 (12–38 μg/L and mean serum zinc concentrations (SD were 12.6 (1.7 μmol/L in fasting samples and 11.8 (2.0 μmol/L in nonfasting samples. For each 1 mg/day increase in dietary iron intake, zinc intake increased by 0.4 mg/day. Each 1 μmol/L increase in serum zinc corresponded to a 6% increase in serum ferritin, however women with low serum zinc concentration (AM fasting < 10.7 μmol/L; AM nonfasting < 10.1 μmol/L were not at increased risk of depleted iron stores (serum ferritin <15 μg/L; p = 0.340. Positive associations were observed between dietary iron and zinc intakes, and between iron and zinc status, however interpreting serum ferritin concentrations was not a useful proxy for estimating the likelihood of low serum zinc concentrations and women with depleted iron stores were not at increased risk of impaired zinc status in this cohort.
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[Blending powdered antineoplastic medicine in disposable ointment container].
Miyazaki, Yasunori; Uchino, Tomonobu; Kagawa, Yoshiyuki
2014-01-01
On dispensing powdered antineoplastic medicines, it is important to prevent cross-contamination and environmental exposure. Recently, we developed a method for blending powdered medicine in a disposable ointment container using a planetary centrifugal mixer. The disposable container prevents cross-contamination. In addition, environmental exposure associated with washing the apparatus does not arise because no blending blade is used. In this study, we aimed to confirm the uniformity of the mixture and weight loss of medicine in the blending procedure. We blended colored lactose powder with Leukerin(®) or Mablin(®) powders using the new method and the ordinary pestle and mortar method. Then, the blending state was monitored using image analysis. Blending variables, such as the blending ratio (1:9-9:1), container size (35-125 mL), and charging rate (20-50%) in the container were also investigated under the operational conditions of 500 rpm and 50 s. At a 20% charging rate in a 35 mL container, the blending precision of the mixtures was not influenced by the blending ratio, and was less than 6.08%, indicating homogeneity. With an increase in the charging rate, however, the blending precision decreased. The possible amount of both mixtures rose to about 17 g with a 20% charging rate in a 125 mL container. Furthermore, weight loss of medicines with this method was smaller than that with the pestle and mortar method, suggesting that this method is safer for pharmacists. In conclusion, we have established a precise and safe method for blending powdered medicines in pharmacies.
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Effects of zinc supplementation and zinc chelation on in vitro β-cell function in INS-1E cells
DEFF Research Database (Denmark)
Nygaard, Sanne Bjørn; Larsen, Agnete; Knuhtsen, Astrid
2014-01-01
BACKGROUND: Zinc is essential for the activities of pancreatic β-cells, especially insulin storage and secretion. Insulin secretion leads to co-release of zinc which contributes to the paracrine communication in the pancreatic islets. Zinc-transporting proteins (zinc-regulated transporter, iron......-regulated transporter-like proteins [ZIPs] and zinc transporters [ZnTs]) and metal-buffering proteins (metallothioneins, MTs) tightly regulate intracellular zinc homeostasis. The present study investigated how modulation of cellular zinc availability affects β-cell function using INS-1E cells. RESULTS: Using INS-1E...... cells, we found that zinc supplementation and zinc chelation had significant effects on insulin content and insulin secretion. Supplemental zinc within the physiological concentration range induced insulin secretion. Insulin content was reduced by zinc chelation with N,N,N',N-tektrakis(2-pyridylmethyl...
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The Optimum Blend: Affordances and Challenges of Blended Learning For Students
Directory of Open Access Journals (Sweden)
Nuray Gedik
2012-03-01
Full Text Available The purpose of this study was to elicit students’ perceptions regarding the most facilitative and most challenging features (affordances and barriers in a blended course design. Following the phenomenological approach of qualitative inquiry, data were collected from ten undergraduate students who had experiences in a blended learning environment. Data were collected from the students’ weekly reşection papers, interviews with students, and documents, and analyzed by structurally and texturally describing the resulting experiences and perceptions. The findings of the study indicate that used together, online and face-to-face course structures offer several opportunities and challenges for students. The participating students mentioned interaction and communication opportunities, increased motivation, increased opportunities to voice their opinions, and reinforcement of learning as the affordances in the blended learning environment. The barriers included increased workload, cultural and technical barriers, and the inter-dependence of the two environments. Implications and suggestions are offered for instructors in higher education settings
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The Optimum Blend: Affordances and Challenges of Blended Learning For Students
Directory of Open Access Journals (Sweden)
Nuray Gedik
2012-07-01
Full Text Available The purpose of this study was to elicit students’ perceptions regarding the most facilitative and most challenging features (affordances and barriers in a blended course design. Following the phenomenological approach of qualitative inquiry, data were collected from ten undergraduate students who had experiences in a blended learning environment. Data were collected from the students’ weekly reflection papers, interviews with students, and documents, and analyzed by structurally and texturally describing the resulting experiences and perceptions. The findings of the study indicate that used together, online and face-to-face course structures offer several opportunities and challenges for students. The participating students mentioned interaction and communication opportunities, increased motivation, increased opportunities to voice their opinions, and reinforcement of learning as the affordances in the blended learning environment. The barriers included increased workload, cultural and technical barriers, and the inter-dependence of the two environments. Implications and suggestions are offered for instructors in higher education settings.
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Nutritional assessment methods for zinc supplementation in prepubertal non-zinc-deficient children
Directory of Open Access Journals (Sweden)
Márcia Marília Gomes Dantas Lopes
2015-10-01
Full Text Available Background: Zinc is an essential nutrient that is required for numerous metabolic functions, and zinc deficiency results in growth retardation, cell-mediated immune dysfunction, and cognitive impairment. Objective: This study evaluated nutritional assessment methods for zinc supplementation in prepubertal non-zinc-deficient children. Design: We performed a randomised, controlled, triple-blind study. The children were divided into a control group (10% sorbitol, n=31 and an experimental group (10 mg Zn/day, n=31 for 3 months. Anthropometric and dietary assessments as well as bioelectrical measurements were performed in all children. Results: Our study showed (1 an increased body mass index for age and an increased phase angle in the experimental group; (2 a positive correlation between nutritional assessment parameters in both groups; (3 increased soft tissue, and mainly fat-free mass, in the body composition of the experimental group, as determined using bioelectrical impedance vector analysis; (4 increased consumption of all nutrients, including zinc, in the experimental group; and (5 an increased serum zinc concentration in both groups (p<0.0001. Conclusions: Given that a reference for body composition analysis does not exist for intervention studies, longitudinal studies are needed to investigate vector migration during zinc supplementation. These results reinforce the importance of employing multiple techniques to assess the nutritional status of populations.
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Baltaci, Abdulkerim Kasım; Mogulkoc, Rasim
2017-06-01
Since zinc mediates the effects of many hormones or is found in the structure of numerous hormone receptors, zinc deficiency leads to various functional impairments in the hormone balance. And also thyroid hormones have important activity on metabolism and feeding. NPY and leptin are affective on food intake and regulation of appetite. The present study is conducted to determine how zinc supplementation and deficiency affect thyroid hormones (free and total T3 and T4), melatonin, leptin, and NPY levels in thyroid dysfunction in rats. The experiment groups in the study were formed as follows: Control (C); Hypothyroidism (PTU); Hypothyroidism+Zinc (PTU+Zn); Hypothyroidism+Zinc deficient; Hyperthyroidism (H); Hyperthyroidism+Zinc (H+Zn); and Hyperthyroidism+Zinc deficient. Thyroid hormone parameters (FT 3 , FT 4 , TT 3 , and TT 4 ) were found to be reduced in hypothyroidism groups and elevated in the hyperthyroidism groups. Melatonin values increased in hyperthyroidism and decreased in hypothyroidism. Leptin and NPY levels both increased in hypo- and hyperthyroidism. Zinc levels, on the other hand, decreased in hypothyroidism and increased in hyperthyroidism. Zinc supplementation, particularly when thyroid function is impaired, has been demonstrated to markedly prevent these changes.
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Wavelet and Blend maps for texture synthesis
Du Jin-Lian; Wang Song; Meng Xianhai
2011-01-01
blending is now a popular technology for large realtime texture synthesis .Nevertheless, creating blend map during rendering is time and computation consuming work. In this paper, we exploited a method to create a kind of blend tile which can be tile together seamlessly. Note that blend map is in fact a kind of image, which is Markov Random Field, contains multiresolution signals, while wavelet is a powerful way to process multiresolution signals, we use wavelet to process the traditional ble...
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Zinc as a Gatekeeper of Immune Function
Directory of Open Access Journals (Sweden)
Inga Wessels
2017-11-01
Full Text Available After the discovery of zinc deficiency in the 1960s, it soon became clear that zinc is essential for the function of the immune system. Zinc ions are involved in regulating intracellular signaling pathways in innate and adaptive immune cells. Zinc homeostasis is largely controlled via the expression and action of zinc “importers” (ZIP 1–14, zinc “exporters” (ZnT 1–10, and zinc-binding proteins. Anti-inflammatory and anti-oxidant properties of zinc have long been documented, however, underlying mechanisms are still not entirely clear. Here, we report molecular mechanisms underlying the development of a pro-inflammatory phenotype during zinc deficiency. Furthermore, we describe links between altered zinc homeostasis and disease development. Consequently, the benefits of zinc supplementation for a malfunctioning immune system become clear. This article will focus on underlying mechanisms responsible for the regulation of cellular signaling by alterations in zinc homeostasis. Effects of fast zinc flux, intermediate “zinc waves”, and late homeostatic zinc signals will be discriminated. Description of zinc homeostasis-related effects on the activation of key signaling molecules, as well as on epigenetic modifications, are included to emphasize the role of zinc as a gatekeeper of immune function.
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Uptake and partitioning of zinc in Lemnaceae.
Lahive, Elma; O'Callaghan, Michael J A; Jansen, Marcel A K; O'Halloran, John
2011-11-01
Macrophytes provide food and shelter for aquatic invertebrates and fish, while also acting as reservoirs for nutrients and trace elements. Zinc accumulation has been reported for various Lemnaceae species. However, comparative accumulation across species and the link between zinc accumulation and toxicity are poorly understood. Morphological distribution and cellular storage, in either bound or soluble form, are important for zinc tolerance. This study shows differences in the uptake and accumulation of zinc by three duckweed species. Landoltia punctata and Lemna minor generally accumulated more zinc than Lemna gibba. L. minor, but not L. gibba or L. punctata, accumulated greater concentrations of zinc in roots compared to fronds when exposed to high levels of zinc. The proportion of zinc stored in the bound form relative to the soluble-form was higher in L. minor. L. punctata accumulated greater concentrations of zinc in fronds compared to roots and increased the proportion of zinc it stored in the soluble form, when exposed to high zinc levels. L. gibba is the only species that significantly accumulated zinc at low concentrations, and was zinc-sensitive. Overall, internal zinc concentrations showed no consistent correlation with toxic effect. We conclude that relationships between zinc toxicity and uptake and accumulation are species specific reflecting, among others, zinc distribution and storage. Differences in zinc distribution and storage are also likely to have implications for zinc bioavailability and trophic mobility.
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Polarization Change in Face-Centered Cubic Opal Films
Wolff, Christian; Romanov, Sergei; Küchenmeister, Jens; Peschel, Ulf; Busch, Kurt
2011-10-01
Artificial opals are a popular platform for investigating fundamental properties of Photonic Crystals (PhC). In this work, we provide a theoretical analysis of polarization-resolved transmission experiments through thin opal films. Despite the full cubic symmetry of the PhC, this system provides a very efficient mechanism for manipulating the polarization state of light. Based on band structure calculations and Bloch mode analysis, we find that this effect closely resembles classical birefringence. Due to the cubic symmetry, however, a description using tensorial quantities is not possible. This indicates fundamental limitations of effective material models for Photonic Crystals and demonstrates the importance of accurately modelling the microscopic geometry of such systems.
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Silk fibroin/pullulan blend films: Preparation and characterization
Energy Technology Data Exchange (ETDEWEB)
Shivananda, C. S.; Rao, B. Lakshmeesha; Madhukumar, R.; Asha, S. [Department of Studies in Physics, Mangalore University, Mangalagangotri – 574 199 (India); Sarojini, B. K. [Department of Industrial Chemistry, Mangalore University, Mangalagangotri, Mangalore –574 199 (India); Somashekhar, R. [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore – 570 006 (India); Sangappa, Y., E-mail: syhalabhavi@yahoo.co.in [Department of Studies in Physics, Mangalore University, Mangalagangotri – 574 199 (India); School of Material Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States)
2016-05-23
In this work silk fibroin/pullulan blend films have been prepared by solution casting method. The blend films were examined for structural, and thermal properties using X-ray diffraction (XRD), thermogravimatric (TGA) and differential scanning calorimetry (DSC) analysis. The XRD results indicate that with the introduction of pullulan, the interaction between SF and pullulan in the blend films induced the conformation transition of SF films and amorphous phase increases with increasing pullulan ratio. The thermal properties of the blend films were improved significantly in the blend films.
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Correspondence Theory and Phonological Blending in French
Directory of Open Access Journals (Sweden)
Lee Scott
2014-07-01
Full Text Available Though less productive than rival word-formation processes like compounding and affixation, blending is still a rich source of neologisms in French. Despite this productivity, however, blends are often seen by scholars as unpredictable, uninteresting, or both. This analysis picks up where recent studies of blending have left off, using Correspondence Theory and a bundle of segmental constraints to deal with this phenomenon as it pertains to French. More specifically, it shows that blending is the result of a single output standing in correspondence with two or more other outputs, and that we do not need to refer to prosodic information, which is crucial in accounts of blending in languages with lexical stress like English, to account for the process in French. The analysis also differs from previous studies in that it locates blending exclusively within the phonology, leaving its morphological and semantic characteristics to be handled by other processes in the grammar.
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Blended working: for whom it may (not work.
Directory of Open Access Journals (Sweden)
Nico W Van Yperen
Full Text Available Similarly to related developments such as blended learning and blended care, blended working is a pervasive and booming trend in modern societies. Blended working combines on-site and off-site working in an optimal way to improve workers' and organizations' outcomes. In this paper, we examine the degree to which workers feel that the two defining features of blended working (i.e., time-independent working and location-independent working enhance their own functioning in their jobs. Blended working, enabled through the continuing advance and improvement of high-tech ICT software, devices, and infrastructure, may be considered beneficial for workers' perceived effectiveness because it increases their job autonomy. However, because blended working may have downsides as well, it is important to know for whom blended working may (not work. As hypothesized, in a sample of 348 workers (51.7% women, representing a wide range of occupations and organizations, we found that the perceived personal effectiveness of blended working was contingent upon workers' psychological need strength. Specifically, the perceived effectiveness of both time-independent working and location-independent working was positively related to individuals' need for autonomy at work, and negatively related to their need for relatedness and need for structure at work.
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Moisture sorption and thermal characteristics of polyaramide blend fabrics
Genç, Gözde; Alp, Burcu; Balköse, Devrim; Ülkü, Semra; Cireli, Aysun
2006-01-01
Four types of fabrics woven from various polyaramid fibers of Nomex and Kevlar blends were characterized by morphology, XRD, elemental analysis, thermal analysis, and moisture adsorption isotherms. The blends consisted of Polybenzimidazole/ Kevlar blend (40% FBI and 60% Kevlar®), Nomex Delta A (blend of 60% Kevlar and 40% Nomex®), Nomex Delta T (blend of 75% Nomex, 23% Kevlar, and 2% P140 antistatic fiber), and Nomex III (fabric with a 95/5 blend of Nomex and Kevlar) containing 1% steel fiber...
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Zinc oxide is an ingredient in many products. Some of these are certain creams and ointments used ... prevent or treat minor skin burns and irritation. Zinc oxide overdose occurs when someone eats one of ...
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Shand, Kristen; Farrelly, Susan Glassett
2017-01-01
In this study, we explore the design and delivery of a blended social studies teaching methods course to examine the elements of the blended design that pre-service teachers found most constructive. In focus groups at the completion of the course, pre-service teachers were asked to reflect on their experience in the blended course, identify the…
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LENRA as compatibilizer in NR/HDPE blends
International Nuclear Information System (INIS)
Dahlan Mohd; Mahathir Mohamed
2006-01-01
Polymer blends of 60/40 NR/RDPE were prepared using Brabender PL2000 Plasticorder with 60 g capacity. The blends were added with radiation-sensitive natural rubber (NR)-based compatibilizer, known as LENRA. They were irradiated with electron-beam radiation at various doses. The efficacy of the compatibilizer was monitored by measuring various properties of the blends such as physical and dynamic mechanical properties including morphological studies by electron microscopic technique. Early results show that the addition of LENRA improves the properties of the TPNR blends. (Author)
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Blended learning within an undergraduate exercise physiology laboratory.
Elmer, Steven J; Carter, Kathryn R; Armga, Austin J; Carter, Jason R
2016-03-01
In physiological education, blended course formats (integration of face-to-face and online instruction) can facilitate increased student learning, performance, and satisfaction in classroom settings. There is limited evidence on the effectiveness of using blending course formats in laboratory settings. We evaluated the impact of blended learning on student performance and perceptions in an undergraduate exercise physiology laboratory. Using a randomized, crossover design, four laboratory topics were delivered in either a blended or traditional format. For blended laboratories, content was offloaded to self-paced video demonstrations (∼15 min). Laboratory section 1 (n = 16) completed blended laboratories for 1) neuromuscular power and 2) blood lactate, whereas section 2 (n = 17) completed blended laboratories for 1) maximal O2 consumption and 2) muscle electromyography. Both sections completed the same assignments (scored in a blinded manner using a standardized rubric) and practicum exams (evaluated by two independent investigators). Pre- and postcourse surveys were used to assess student perceptions. Most students (∼79%) watched videos for both blended laboratories. Assignment scores did not differ between blended and traditional laboratories (P = 0.62) or between sections (P = 0.91). Practicum scores did not differ between sections (both P > 0.05). At the end of the course, students' perceived value of the blended format increased (P learning key foundational content through video demonstrations before class greatly enhanced their learning of course material compared with a preassigned reading (94% vs. 78%, P Blended exercise physiology laboratories provided an alternative method for delivering content that was favorably perceived by students and did not compromise student performance. Copyright © 2016 The American Physiological Society.
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A Phase Blending Study on Rubber Blends Based on the Solubility Preference of Curatives
Guo, R.; Talma, Auke; Datta, Rabin; Dierkes, Wilma K.; Noordermeer, Jacobus W.M.
2009-01-01
Using previously obtained data on the solubilities of curatives in SBR, EPDM and in NBR, different mixing procedures were performed on 50/50 SBR/EPDM and NBR/EPDM blends. In contrast to a previous phase-mixing study, the curatives were added to separate phases before final blending, in an attempt to
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Bhat, Nagesh; Jain, Sandeep; Asawa, Kailash; Tak, Mridula; Shinde, Kushal; Singh, Anukriti; Gandhi, Neha; Gupta, Vivek Vardhan
2015-10-01
As of late, natural contamination has stimulated as a reaction of mechanical and other human exercises. In India, with the expanding industrialization, numerous unsafe substances are utilized or are discharged amid generation as cleans, exhaust, vapours and gasses. These substances at last are blended in the earth and causes health hazards. To determine concentration of fluoride in soils and vegetables grown in the vicinity of Zinc Smelter, Debari, Udaipur, Rajasthan. Samples of vegetables and soil were collected from areas situated at 0, 1, 2, 5, and 10 km distance from the zinc smelter, Debari. Three samples of vegetables (i.e. Cabbage, Onion and Tomato) and 3 samples of soil {one sample from the upper layer of soil (i.e. 0 to 20 cm) and one from the deep layer (i.e. 20 - 40 cm)} at each distance were collected. The soil and vegetable samples were sealed in clean polythene bags and transported to the laboratory for analysis. One sample each of water and fertilizer from each distance were also collected. The mean fluoride concentration in the vegetables grown varied between 0.36 ± 0.69 to 0.71 ± 0.90 ppm. The fluoride concentration in fertilizer and water sample from various distances was found to be in the range of 1.4 - 1.5 ppm and 1.8 - 1.9 ppm respectively. The fluoride content of soil and vegetables was found to be higher in places near to the zinc smelter.
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Blended Learning: An Innovative Approach
Lalima; Dangwal, Kiran Lata
2017-01-01
Blended learning is an innovative concept that embraces the advantages of both traditional teaching in the classroom and ICT supported learning including both offline learning and online learning. It has scope for collaborative learning; constructive learning and computer assisted learning (CAI). Blended learning needs rigorous efforts, right…
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Total Positivity of the Cubic Trigonometric Bézier Basis
Directory of Open Access Journals (Sweden)
Xuli Han
2014-01-01
Full Text Available Within the general framework of Quasi Extended Chebyshev space, we prove that the cubic trigonometric Bézier basis with two shape parameters λ and μ given in Han et al. (2009 forms an optimal normalized totally positive basis for λ,μ∈(-2,1]. Moreover, we show that for λ=-2 or μ=-2 the basis is not suited for curve design from the blossom point of view. In order to compute the corresponding cubic trigonometric Bézier curves stably and efficiently, we also develop a new corner cutting algorithm.
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LENRA as compatibilizer in NR/HDPE blends
International Nuclear Information System (INIS)
Mahathir Mohamed; Dahlan Mohd
2004-01-01
Polymer blends of 60/40 NR/HDPE were prepared using Brabender PL2000 plasticorder with 60g capacity. The blends were added with radiation sensitive natural rubber (NR)-based compatibilizer, known as LENRA. They were irradiated in air with electron beam radiation at various doses. The efficacy of the compatibilizer was monitored by measuring various properties of the blends such as physical and dynamic mechanical properties including morphological studies by electron microscopic technique. Early results show that the addition of LENRA improves the properties of the TPNR blends. (Author)
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Performance evaluation of gamma irradiated SiR-EPDM blends
Energy Technology Data Exchange (ETDEWEB)
Deepalaxmi, R., E-mail: deepalaxmivaithi@gmail.com; Rajini, V.
2014-07-01
Highlights: • The effects of gamma irradiation on SiR-EPDM blend are examined. • Cross-linking reaction is dominant in blends C, D and E, due to higher EPDM content. • The tensile strength and hardness of blend E is improved by gamma irradiation. • The blend C and EPDM rich blends (D, E) are found to have superior performance. • Among C, D and E, suitable blend can be selected for a particular NPP application. - Abstract: Cable insulation materials (CIM) should perform their safety functions throughout their installed life in nuclear power plants (NPP). The CIM will be exposed to gamma irradiation at the installed locations. In order to forecast long-term performance of CIM, the short time accelerated testing was carried out. Due to its good mechanical strength, ethylene propylene diene monomer (EPDM) is widely used as CIM. Silicone rubber (SiR) is used in high temperature environments, due to its good di-electric properties/hydrophobicity. The blending of these two polymers may result in the improvement in their specific properties. This paper analyses the effects of gamma irradiation on the five different compositions (90-10; 70-30; 50-50; 30-70; 10-90) of SiR-EPDM blends. The blends were exposed to four different doses (25 Mrad, 100 Mrad, 200 Mrad and 250 Mrad) of gamma irradiation. The electrical and mechanical parameters like volume resistivity (VRY), surface resistivity (SRY), tensile strength (TS), elongation at break (EB), hardness (H) of the virgin and gamma irradiated blends were determined as per ASTM/IEC standards. The nature of degradation was investigated using Fourier transform infrared spectroscopy (FTIR). The simultaneous occurrence of cross-linking and chain scission is found to be the mechanism for ageing in SiR-EPDM blends. The electrical parameters such as volume resistivity and surface resistivity of all the blends are found to improve for all doses of gamma irradiation. To validate the influence of cross-linking reaction of the Si
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Elseweidy, Mohamed M; Ali, Abdel-Moniem A; Elabidine, Nabila Zein; Mursey, Nada M
2017-11-01
The relationship between zinc homeostasis and pancreatic function had been established. In this study we aimed firstly to configure the inflammatory pattern and hyperglycemia in zinc deficient diabetic rats. Secondly to illustrate the effect of two selected agents namely Zinc gluconate and sage oil (Salvia Officinalis, family Lamiaceae). Rats were fed on Zinc deficient diet, deionized water for 28days along with Zinc level check up at intervals to achieve zinc deficient state then rats were rendered diabetic through receiving one dose of alloxan monohydrate (120mg/kg) body weight, classified later into 5 subgroups. Treatment with sage oil (0.042mg/kg IP) and Zinc gluconate orally (150mg/kg) body weight daily for 8 weeks significantly reduced serum glucose, C-reactive protein (CRP), Tumor necrosis factor alpha (TNF- α), interleukins-6 1 β, inflammatory8 (IFN ȣ), pancreatic 1L1-β along with an increase in serum Zinc and pancreatic Zinc transporter 8 (ZNT8). Histopathological results of pancreatic tissues showed a good correlation with the biochemical findings. Both sage oil and zinc gluconate induced an improvement in the glycemic and inflammatory states. This may be of value like the therapeutic agent for diabetes. Copyright © 2017 Elsevier Masson SAS. All rights reserved.
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INVESTIGATION OF CURVES SET BY CUBIC DISTRIBUTION OF CURVATURE
Directory of Open Access Journals (Sweden)
S. A. Ustenko
2014-03-01
Full Text Available Purpose. Further development of the geometric modeling of curvelinear contours of different objects based on the specified cubic curvature distribution and setpoints of curvature in the boundary points. Methodology. We investigate the flat section of the curvilinear contour generating under condition that cubic curvature distribution is set. Curve begins and ends at the given points, where angles of tangent slope and curvature are also determined. It was obtained the curvature equation of this curve, depending on the section length and coefficient c of cubic curvature distribution. The analysis of obtained equation was carried out. As well as, it was investigated the conditions, in which the inflection points of the curve are appearing. One should find such an interval of parameter change (depending on the input data and the section length, in order to place the inflection point of the curvature graph outside the curve section borders. It was determined the dependence of tangent slope of angle to the curve at its arbitrary point, as well as it was given the recommendations to solve a system of integral equations that allow finding the length of the curve section and the coefficient c of curvature cubic distribution. Findings. As the result of curves research, it is found that the criterion for their selection one can consider the absence of inflection points of the curvature on the observed section. Influence analysis of the parameter c on the graph of tangent slope angle to the curve showed that regardless of its value, it is provided the same rate of angle increase of tangent slope to the curve. Originality. It is improved the approach to geometric modeling of curves based on cubic curvature distribution with its given values at the boundary points by eliminating the inflection points from the observed section of curvilinear contours. Practical value. Curves obtained using the proposed method can be used for geometric modeling of curvilinear
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Blended Learning: A Dangerous Idea?
Moskal, Patsy; Dziuban, Charles; Hartman, Joel
2013-01-01
The authors make the case that implementation of a successful blended learning program requires alignment of institutional, faculty, and student goals. Reliable and robust infrastructure must be in place to support students and faculty. Continuous evaluation can effectively track the impact of blended learning on students, faculty, and the…
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Empowering Learners through Blended Learning
Owston, Ron
2018-01-01
Blended learning appears to facilitate learner empowerment more readily than either face-to-face or fully online courses. This contention is supported by a review of literature on the affordances of blended learning that support Thomas and Velthouse's (1990) four conditions of empowerment: choice, meaningfulness, competence, and impact. Blended…
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The Basics of Blended Instruction
Tucker, Catlin R.
2013-01-01
Even though many of teachers do not have technology-rich classrooms, the rapidly evolving education landscape increasingly requires them to incorporate technology to customize student learning. Blended learning, with its mix of technology and traditional face-to-face instruction, is a great approach. Blended learning combines classroom learning…
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The Art of Blending: Benefits and Challenges of a Blended Course for Preservice Teachers
Shand, Kristen; Farrelly, Susan Glassett
2018-01-01
In this study, we explore the design and delivery of a blended social studies teaching methods course according to principles and core attributes of blended course design. In a survey at the end of the course, pre-service teachers were asked to reflect on their experience in the course, and identify the benefits and challenges of the blended…
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Structural property of platinum mononitride
International Nuclear Information System (INIS)
Yu, L.H.; Yao, K.L.; Liu, Z.L.; Zhang, Y.S.
2007-01-01
The structural stability and pressure-induced structural phase transition of platinum mononitride (PtN), as well as its electronic structure, were studied using the full potential augmented plane wave plus local orbitals method with the generalized gradient approximation (GGA) exchange-correlation functional. The total energy calculations show that the optimized wurtzite structure is most stable energetically among four structures: zinc blende, rocksalt, CsCl and wurtzite, which reveals the platinum mononitride PtN perhaps crystallizes in the wurtzite structure; the pressure of phase transition from wurtzite to rocksalt is predicted to be 41.4 GPa.The calculated bulk modulus of the wurtzite structure is 99.41 GPa, which is smaller than that of the other three structures and face-centered cubic Pt. The band structure calculations show wurtzite PtN is metallic
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International Nuclear Information System (INIS)
Wei, Xia; Desai, Divyaraj; Yadav, Gautam G.; Turney, Damon E.; Couzis, Alexander; Banerjee, Sanjoy
2016-01-01
Electrochemical behavior of Ag, Bi, Cu, Fe, Ni and Sn substrates on zinc deposition was evaluated over battery cycling by cyclic voltammetry and electrochemical impedance spectroscopy. The effect of Bi, Cu, Ni, and Sn substrates on zinc electrodeposition during battery cycling was investigated using scanning electron microscopy and X-ray diffraction. The corrosion behavior of each metal in 9 M KOH and the corrosion rates of zinc plated on each substrate were analyzed by Tafel extrapolation method from the potentiodynamic polarization curves and electrochemical impedance spectroscopy. Although the charge-transfer resistance (R_c_t) of zinc electrodeposition is lowest on Sn, Sn eventually corrodes on cycling in alkaline media. Use of Ni as a substrate causes zinc to deteriorate on account of rapid hydrogen evolution. Bi and Cu substrates are more suitable for use as current collectors in zinc-anode alkaline rechargeable batteries because of their low corrosion rate and compact zinc deposition over battery cycling.
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Tank 21 and Tank 24 Blend and Feed Study: Blending Times, Settling Times, and Transfers
International Nuclear Information System (INIS)
Lee, S.; Leishear, R.; Poirier, M.
2012-01-01
The Salt Disposition Integration (SDI) portfolio of projects provides the infrastructure within existing Liquid Waste facilities to support the startup and long term operation of the Salt Waste Processing Facility (SWPF). Within SDI, the Blend and Feed Project will equip existing waste tanks in the Tank Farms to serve as Blend Tanks where salt solutions of up to 1.2 million gallons will be blended in 1.3 million gallon tanks and qualified for use as feedstock for SWPF. In particular, Tanks 21 and 24 are planned to be used for blending and transferring to the SDI feed tank. These tanks were evaluated here to determine blending times, to determine a range of settling times for disturbed sludge, and to determine that the SWPF Waste Acceptance Criteria that less than 1200 mg/liter of solids will be entrained in salt solutions during transfers from the Tank 21 and Tank 24 will be met. Overall conclusions for Tank 21 and Tank 24 operations include: (1) Experimental correction factors were applied to CFD (computational fluid dynamics) models to establish blending times between approximately two and five hours. As shown in Phase 2 research, blending times may be as much as ten times greater, or more, if lighter fluids are added to heavier fluids (i.e., water added to salt solution). As the densities of two salt solutions converge this effect may be minimized, but additional confirmatory research was not performed. (2) At the current sludge levels and the presently planned operating heights of the transfer pumps, solids entrainment will be less than 1200 mg/liter, assuming a conservative, slow settling sludge simulant. (3) Based on theoretical calculations, particles in the density range of 2.5 to 5.0 g/mL must be greater than 2-4 (micro)m in diameter to ensure they settle adequately in 30-60 days to meet the SWPF feed criterion ( 60 days) settling times in Tank 21.
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Danscher, Gorm; Stoltenberg, Meredin; Bruhn, Mikkel; Søndergaard, Chris; Jensen, Dorete
2004-12-01
In the mid-1980s, two versions of Timm's original immersion sulfide silver method were published. The authors used immersion of tissue in a sulfide solution as opposed to Timm, who used immersion of tissue blocks in hydrogen sulfide-bubbled alcohol. The autometallography staining resulting from the "sulfide only immersion" was not particularly impressive, but the significance of this return to an old approach became obvious when Wenzel and co-workers presented their approach in connection with introduction by the Palmiter group of zinc transporter 3 (ZnT3). The Wenzel/Palmiter pictures are the first high-resolution, high-quality pictures taken from tissues in which free and loosely bound zinc ions have been captured in zinc-sulfur nanocrystals by immersion. The trick was to place formalin-fixed blocks of mouse brains in a solution containing 3% glutaraldehyde and 0.1% sodium sulfide, ingredients used for transcardial perfusion in the zinc-specific NeoTimm method. That the NeoTimm technique results in silver enhancement of zinc-sulfur nanocrystals has been proved by proton-induced X-ray multielement analyses (PIXE) and in vivo chelation with diethyldithiocarbamate (DEDTC). The aims of the present study were (a) to make the immersion-based capturing of zinc ions in zinc-sulfur nanocrystals work directly on sections and slices of fixed brain tissue, (b) to work out protocols that ensure zinc specificity and optimal quality of the staining, (c) to apply "immersion autometallography" (iZnSAMG) to other tissues that contain zinc-enriched (ZEN) cells, and (d) to make the immersion approach work on unfixed fresh tissue.
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A local cubic smoothing in an adaptation mode
International Nuclear Information System (INIS)
Dikoussar, N.D.
2001-01-01
A new approach to a local curve approximation and the smoothing is proposed. The relation between curve points is defined using a special cross-ratio weight functions. The coordinates of three curve points are used as parameters for both the weight functions and the tree-point cubic model (TPS). A very simple in computing and stable to random errors cubic smoother in an adaptation mode (LOCUS) is constructed. The free parameter of TPS is estimated independently of the fixed parameters by recursion with the effective error suppression and can be controlled by the cross-ratio parameters. Efficiency and the noise stability of the algorithm are confirmed by examples and by comparison with other known non-parametric smoothers
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Energy Technology Data Exchange (ETDEWEB)
Gil, Eun S. [Fiber and Polymer Science Program, North Carolina State University, Raleigh, NC 27695 (United States); Frankowski, David J. [Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695 (United States); Hudson, Samuel M. [Fiber and Polymer Science Program, North Carolina State University, Raleigh, NC 27695 (United States); Spontak, Richard J. [Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695 (United States) and Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695 (United States)]. E-mail: Rich_Spontak@ncsu.edu
2007-04-15
Protein membranes have been prepared by mixing gelatin (G) with Bombyx mori silk fibroin (SF) and using aqueous methanol (MeOH) to induce SF crystallization. Amorphous blends of these polymers appear quasi-homogeneous, as discerned from visual observation, electron microscopy and Fourier-transform infrared (FTIR) spectroscopy. Upon subsequent exposure to aqueous MeOH, SF undergoes a conformational change from random-coil to {beta}-sheet. This transformation occurs in pure SF, as well as in each of the G/SF blends, as discerned from FTIR spectroscopy and thermal calorimetry. The influence of MeOH-induced SF crystallization on structure and property development has been measured as functions of blend and solvent composition. By preserving a support scaffold above the G helix-to-coil transition temperature, the formation of crystalline SF networks in G/SF blends can be used to stabilize G-based hydrogels or generate SF membranes for biomaterial, pharmaceutical and gas-separation purposes. The present study not only examines the properties of G/SF blends before and after SF crystallization, but also establishes the foundation for future research into thermally-responsive G/SF bioconjugates.
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Phase transformation of metastable cubic γ-phase in U-Mo alloys
International Nuclear Information System (INIS)
Sinha, V.P.; Hegde, P.V.; Prasad, G.J.; Dey, G.K.; Kamath, H.S.
2010-01-01
Over the past decade considerable efforts have been put by many fuel designers to develop low enriched uranium (LEU 235 ) base U-Mo alloy as a potential fuel for core conversion of existing research and test reactors which are running on high enriched uranium (HEU > 85%U 235 ) fuel and also for the upcoming new reactors. U-Mo alloy with minimum 8 wt% molybdenum shows excellent metastability with cubic γ-phase in cast condition. However, it is important to characterize the decomposition behaviour of metastable cubic γ-uranium in its equilibrium products for in reactor fuel performance point of view. The present paper describes the phase transformation behaviour of cubic γ-uranium phase in U-Mo alloys with three different molybdenum compositions (i.e. 8 wt%, 9 wt% and 10 wt%). U-Mo alloys were prepared in an induction melting furnace and characterized by X-ray diffraction (XRD) method for phase determination. Microstructures were developed for samples in as cast condition. The alloys were hot rolled in cubic γ-phase to break the cast structure and then they were aged at 500 o C for 68 h and 240 h, so that metastable cubic γ-uranium will undergo eutectoid decomposition to form equilibrium phases of orthorhombic α-uranium and body centered tetragonal U 2 Mo intermetallic compound. U-Mo alloy samples with different ageing history were then characterized by XRD for phase and development of microstructure.
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Structural evolution of self-assisted GaAs nanowires grown on Si(111)
Energy Technology Data Exchange (ETDEWEB)
Biermanns, Andreas; Davydok, Anton; Pietsch, Ullrich [University of Siegen, Solid State Physics Group, Walter-Flex-Str. 3, 57072 Siegen (Germany); Breuer, Steffen; Geelhaar, Lutz [Paul-Drude-Institut fuer Festkoerperelektronik, Hausvogteiplatz 5-7, 10117 Berlin (Germany)
2011-04-15
GaAs nanowires are grown on Si(111) by self-assisted molecular beam epitaxy, and the ratio between wurtzite and zinc-blende phases is determined as function of nanowire length using asymmetric X-ray diffraction. We show that under the applied growth conditions, nanowires grow in both phases during the initial stage of growth, whereas the zinc-blende content increases with growth time and dominates in long nanowires. Compared to the zinc-blende units, the vertical lattice parameter of the wurtzite segments is 0.7% larger, as measured by the positions of respective diffraction peaks. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)
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NESDIS Blended Rain Rate (RR) Products
National Oceanic and Atmospheric Administration, Department of Commerce — The blended Rain Rate (RR) product is derived from multiple sensors/satellites. The blended products were merged from polar-orbiting and geostationary satellite...
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Energy Technology Data Exchange (ETDEWEB)
Que, Emily L.; Bleher, Reiner; Duncan, Francesca E.; Kong, Betty Y.; Gleber, Sophie C.; Vogt, Stefan; Chen, Si; Garwin, Seth A.; Bayer, Amanda R.; Dravid, Vinayak P.; Woodruff, Teresa K.; O' Halloran, Thomas V.
2014-12-15
Fertilization of a mammalian egg initiates a series of 'zinc sparks' that are necessary to induce the egg-to-embryo transition. Despite the importance of these zinc-efflux events little is known about their origin. To understand the molecular mechanism of the zinc spark we combined four physical approaches that resolve zinc distributions in single cells: a chemical probe for dynamic live-cell fluorescence imaging and a combination of scanning transmission electron microscopy with energy-dispersive spectroscopy, X-ray fluorescence microscopy and three-dimensional elemental tomography for high-resolution elemental mapping. We show that the zinc spark arises from a system of thousands of zinc-loaded vesicles, each of which contains, on average, 10(6) zinc atoms. These vesicles undergo dynamic movement during oocyte maturation and exocytosis at the time of fertilization. The discovery of these vesicles and the demonstration that zinc sparks originate from them provides a quantitative framework for understanding how zinc fluxes regulate cellular processes
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Cubic Invariant Spherical Surface Harmonics in Conjunction With Diffraction Strain Pole-Figures
Brakman, C.M.
1986-01-01
Four kinds of cubic invariant spherical surface harmonics are introduced. It has been shown previously that these harmonics occur in the equations relating measured diffraction (line-shift) elastic strain and macro-stresses generating these strains for the case of textured cubic materials. As a
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Novel bio-based and biodegradable polymer blends
Yang, Shengzhe
Most plastic materials, including high performance thermoplastics and thermosets are produced entirely from petroleum-based products. The volatility of the natural oil markets and the increasing cost of petroleum have led to a push to reduce the dependence on petroleum products. Together with an increase in environmental awareness, this has promoted the use of alternative, biorenewable, environmentally-friendly products, such as biomass. The growing interest in replacing petroleum-based products by inexpensive, renewable, natural materials is important for sustainable development into the future and will have a significant impact on the polymer industry and the environment. This thesis involved characterization and development of two series of novel bio-based polymer blends, namely polyhydroxyalkanoate (PHA)/polyamide (PA) and poly(lactic acid) (PLA)/soy protein. Blends with different concentrations and compatible microstructures were prepared using twin-screw extruder. For PHA/PA blends, the poor mechanical properties of PHA improved significantly with an excellent combination of strength, stiffness and toughness by adding PA. Furthermore, the effect of blending on the viscoelastic properties has been investigated using small-amplitude oscillatory shear flow experiments as a function of blend composition and angular frequency. The elastic shear modulus (G‧) and complex viscosity of the blends increased significantly with increasing the concentration of PHA. Blending PLA with soy protein aims at reducing production cost, as well as accelerating the biodegradation rate in soil medium. In this work, the mechanical, thermal and morphological properties of the blends were investigated using dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and tensile tests.
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Study of the cubic - to - monoclinic transformation in magnesia partially stabilized zirconia
International Nuclear Information System (INIS)
Muccillo, R.
1988-01-01
The transformation of the cubic phase to the stable monoclinic phase in ZrO 2 : 3%MgO quenched from 1450 0 C to RT has been studied by X-ray diffractometry in order to explain the thermal hysteresis in the electrical conductivity. The monoclinic-to-cubic ratio has been measured for samples annealed in the 500 0 C-1000 0 C temperature range. The results show that the decrease in the cubic phase content is the main responsible for the thermal hysteresis in the electrical conductivity of the magnesia partially stabilized zirconia solid electrolytes. (author) [pt
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Clinical Aspects of Trace Elements: Zinc in Human Nutrition – Zinc Deficiency and Toxicity
Directory of Open Access Journals (Sweden)
Michelle M Pluhator
1996-01-01
Full Text Available Available evidence suggests that trace elements, such as zinc, once thought to have no nutritional relevance, are possibly deficient in large sections of the human population. Conditioned deficiencies have been reported to result from malabsorption syndromes, acrodermatitis enteropathica, alcoholism, gastrointestinal disease, thermal injury, chronic diseases (eg, diabetes, sickle cell anemia, and in total parenteral nutrition therapy. Awareness that patients with these problems are at risk has led health professionals to focus increasingly on the importance of zinc therapy in the prevention and treatment of deficiency. More recently zinc toxicity and its role in human nutrition and well-being have come under investigation. Reports have focused on the role of zinc toxicity in causes of copper deficiency, changes in the immune system and alterations in blood lipids. As the numerous challenges presented by the study of zinc in human nutrition are met, more appropriate recommendations for dietary and therapeutic zinc intake are being made.
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The processing of blend words in naming and sentence reading.
Johnson, Rebecca L; Slate, Sarah Rose; Teevan, Allison R; Juhasz, Barbara J
2018-04-01
Research exploring the processing of morphologically complex words, such as compound words, has found that they are decomposed into their constituent parts during processing. Although much is known about the processing of compound words, very little is known about the processing of lexicalised blend words, which are created from parts of two words, often with phoneme overlap (e.g., brunch). In the current study, blends were matched with non-blend words on a variety of lexical characteristics, and blend processing was examined using two tasks: a naming task and an eye-tracking task that recorded eye movements during reading. Results showed that blend words were processed more slowly than non-blend control words in both tasks. Blend words led to longer reaction times in naming and longer processing times on several eye movement measures compared to non-blend words. This was especially true for blends that were long, rated low in word familiarity, but were easily recognisable as blends.
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Evaluation of non-linear blending in dual-energy computed tomography
International Nuclear Information System (INIS)
Holmes, David R.; Fletcher, Joel G.; Apel, Anja; Huprich, James E.; Siddiki, Hassan; Hough, David M.; Schmidt, Bernhard; Flohr, Thomas G.; Robb, Richard; McCollough, Cynthia; Wittmer, Michael; Eusemann, Christian
2008-01-01
Dual-energy CT scanning has significant potential for disease identification and classification. However, it dramatically increases the amount of data collected and therefore impacts the clinical workflow. One way to simplify image review is to fuse CT datasets of different tube energies into a unique blended dataset with desirable properties. A non-linear blending method based on a modified sigmoid function was compared to a standard 0.3 linear blending method. The methods were evaluated in both a liver phantom and patient study. The liver phantom contained six syringes of known CT contrast which were placed in a bovine liver. After scanning at multiple tube currents (45, 55, 65, 75, 85, 95, 105, and 115 mAs for the 140-kV tube), the datasets were blended using both methods. A contrast-to-noise (CNR) measure was calculated for each syringe. In addition, all eight scans were normalized using the effective dose and statistically compared. In the patient study, 45 dual-energy CT scans were retrospectively mixed using the 0.3 linear blending and modified sigmoid blending functions. The scans were compared visually by two radiologists. For the 15, 45, and 64 HU syringes, the non-linear blended images exhibited similar CNR to the linear blended images; however, for the 79, 116, and 145 HU syringes, the non-linear blended images consistently had a higher CNR across dose settings. The radiologists qualitatively preferred the non-linear blended images of the phantom. In the patient study, the radiologists preferred non-linear blending in 31 of 45 cases with a strong preference in bowel and liver cases. Non-linear blending of dual energy data can provide an improvement in CNR over linear blending and is accompanied by a visual preference for non-linear blended images. Further study on selection of blending parameters and lesion conspicuity in non-linear blended images is being pursued
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Zinc in Infection and Inflammation.
Gammoh, Nour Zahi; Rink, Lothar
2017-06-17
Micronutrient homeostasis is a key factor in maintaining a healthy immune system. Zinc is an essential micronutrient that is involved in the regulation of the innate and adaptive immune responses. The main cause of zinc deficiency is malnutrition. Zinc deficiency leads to cell-mediated immune dysfunctions among other manifestations. Consequently, such dysfunctions lead to a worse outcome in the response towards bacterial infection and sepsis. For instance, zinc is an essential component of the pathogen-eliminating signal transduction pathways leading to neutrophil extracellular traps (NET) formation, as well as inducing cell-mediated immunity over humoral immunity by regulating specific factors of differentiation. Additionally, zinc deficiency plays a role in inflammation, mainly elevating inflammatory response as well as damage to host tissue. Zinc is involved in the modulation of the proinflammatory response by targeting Nuclear Factor Kappa B (NF-κB), a transcription factor that is the master regulator of proinflammatory responses. It is also involved in controlling oxidative stress and regulating inflammatory cytokines. Zinc plays an intricate function during an immune response and its homeostasis is critical for sustaining proper immune function. This review will summarize the latest findings concerning the role of this micronutrient during the course of infections and inflammatory response and how the immune system modulates zinc depending on different stimuli.
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Magnetic ground states in nanocuboids of cubic magnetocrystalline anisotropy
Energy Technology Data Exchange (ETDEWEB)
Bonilla, F.J., E-mail: fbonilla@cicenergigune.com; Lacroix, L.-M.; Blon, T., E-mail: thomas.blon@insa-toulouse.fr
2017-04-15
Flower and easy-axis vortex states are well-known magnetic configurations that can be stabilized in small particles. However, <111> vortex (V<111>), i.e. a vortex state with its core axis along the hard-axis direction, has been recently evidenced as a stable configuration in Fe nanocubes of intermediate sizes in the flower/vortex transition. In this context, we present here extensive micromagnetic simulations to determine the different magnetic ground states in ferromagnetic nanocuboids exhibiting cubic magnetocrystalline anisotropy (MCA). Focusing our study in the single-domain/multidomain size range (10–50 nm), we showed that V<111> is only stable in nanocuboids exhibiting peculiar features, such as a specific size, shape and magnetic environment, contrarily to the classical flower and easy-axis vortex states. Thus, to track experimentally these V<111> states, one should focused on (i) nanocuboids exhibiting a nearly perfect cubic shape (size distorsion <12%) made of (ii) a material which combines a zero or positive MCA and a high saturation magnetization, such as Fe or FeCo; and (iii) a low magnetic field environment, V<111> being only observed in virgin or remanent states. - Highlights: • The <111> vortex is numerically determined in nanocubes of cubic anisotropy. • It constitutes an intermediate state in the single-domain limit. • Such a vortex can only be stabilized in perfect or slightly deformed nanocuboids. • It exists in nanocuboids made of materials with zero or positive cubic anisotropy. • The associated magnetization reversal is described by a rotation of the vortex axis.
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Neutron diffraction study of cubic titanium carbohydride at the homogeneity lower limit
International Nuclear Information System (INIS)
Khidirov, I.; Mirzaev, B.B.; Mukhtarova, N.N.
2004-01-01
Cubic carbohydride TiC 0.47H0.22 was prepared by means of quenching from 1200 deg.C followed by the heat treatment using special regime for preventing the hydrogen yield out the lattice. It is shown that at the lower limit of homogeneity range of the cubic carbohydride, hydrogen atoms occupy the tetrahedral interstices 8(c) of the disordered cubic structure with space group of Fm3m. It is found that carbon and hydrogen atoms are partially ordered by annealing at 900-700 deg.C. The ordered structure is face-centred cubic lattice with the parameter a ≅2a 0 , where a 0 is the lattice parameter in disordered structure. The crystal structure of the disordered phase is described within the framework of space group Fd3m, where the carbon atoms occupy mainly (70%) octahedral interstices 16(c) and another ones of carbon and all hydrogen atoms occupy the octahedral interstices 16(d). (author)
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Influence of usual zinc intake and zinc in a meal on 65Zn retention and turnover in the rat
International Nuclear Information System (INIS)
Hunt, J.R.; Johnson, P.E.; Swan, P.B.
1987-01-01
The influences of zinc in a meal and usual zinc intake on zinc retention and turnover were investigated in 7-wk-old male rats fed diets containing 12-151 mg Zn/kg for 3 wk before and after consuming a 65 Zn-labeled meal containing ZnCl 2 . Retention corrected to zero time and turnover rate were determined by whole-body counting. Percent zinc retention was inversely proportional to the natural logarithm of the meal zinc, between 0.09 and 26 mumol. In comparison to lower doses, higher doses resulted in lower percent retention but greater amounts of zinc retained. Although the latter relationship was slightly curvilinear, there was no indication of a limited capacity for zinc retention with high doses. However, doses above 4 mumol resulted in higher turnover rates in rats accustomed to lower zinc intakes. Percent retention and the reciprocal of the turnover rate were proportional to the reciprocal of the dietary zinc concentration. The greatest differences in retention and turnover occurred between 12 and 26 mg Zn/kg diet. The zinc dose in a meal and the usual dietary zinc separately influenced percent zinc retention. These factors also interacted, such that greater dose effects were observed at lower zinc intakes and greater dietary zinc effects were observed at lower doses
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Kocyła, Anna; Adamczyk, Justyna; Krężel, Artur
2018-01-24
Cellular zinc (Zn(ii)) is bound with proteins that are part of the proteomes of all domains of life. It is mostly utilized as a catalytic or structural protein cofactor, which results in a vast number of binding architectures. The Zn(ii) ion is also important for the formation of transient protein complexes with a Zn(ii)-dependent quaternary structure that is formed upon cellular zinc signals. The mechanisms by which proteins associate with and dissociate from Zn(ii) and the connection with cellular Zn(ii) changes remain incompletely understood. In this study, we aimed to examine how zinc protein domains with various Zn(ii)-binding architectures are formed under free Zn(ii) concentration changes and how formation of the Zn(ii)-dependent assemblies is related to the protein concentration and reactivity. To accomplish these goals we chose four zinc domains with different Zn(ii)-to-protein binding stoichiometries: classical zinc finger (ZnP), LIM domain (Zn 2 P), zinc hook (ZnP 2 ) and zinc clasp (ZnP 1 P 2 ) folds. Our research demonstrated a lack of changes in the saturation level of intraprotein zinc binding sites, despite various peptide concentrations, while homo- and heterodimers indicated a concentration-dependent tendency. In other words, at a certain free Zn(ii) concentration, the fraction of a formed dimeric complex increases or decreases with subunit concentration changes. Secondly, even small or local changes in free Zn(ii) may significantly affect protein saturation depending on its architecture, function and subcellular concentration. In our paper, we indicate the importance of interdependence of free Zn(ii) availability and protein subunit concentrations for cellular zinc signal regulation.
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Classifying K-12 Blended Learning
Staker, Heather; Horn, Michael B.
2012-01-01
The growth of online learning in the K-12 sector is occurring both remotely through virtual schools and on campuses through blended learning. In emerging fields, definitions are important because they create a shared language that enables people to talk about the new phenomena. The blended-learning taxonomy and definitions presented in this paper…
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Radiation crosslinking of polymer blends
International Nuclear Information System (INIS)
Spenadel, L.
1979-01-01
Rocked by the one-two punch of rising energy costs and tougher pollution controls, a growing number of companies are looking to radiation crosslinking as a cheaper, cleaner alternative to heat and costly chemical crosslinking agents such as peroxides. With the development of larger, more powerful electron beam machines it is now possible to irradiate parts as thick as 400 mils in a single pass. Two application areas which have been investigated at our laboratory are the electron beam processing of thermoplastic elastomeric automotive parts and EPDM electrical insulation. This paper covers work carried out to develop the necessary technology base for the radiation crosslinking of ethylene propylene/polyolefin blends. Initial results indicate that EP/PE blends of electrical insulation quality cross-link quite readily when irradiated. On the other hand, EP/PP blends developed for automotive fascia require the addition of crosslinking monomers such as trimethylol propane trimethacrylate in order for crosslinking to predominate over chain scission. Crosslinking EP/PP blends improve mar resistance, flexural set and deformation at elevated temperatures. These are all key properties for automotive fascia. (author)
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Khandal, Dhriti; Mikus, Pierre-Yves; Dole, Patrice; Coqueret, Xavier
2013-03-01
This paper reports on the effects of electron beam (EB) irradiation on poly α-1,4-glucose oligomers (maltodextrins) in the presence of water and of various aromatic additives, as model blends for gaining a better understanding at a molecular level the modifications occurring in amorphous starch-lignin blends submitted to ionizing irradiation for improving the properties of this type of bio-based thermoplastic material. A series of aromatic compounds, namely p-methoxy benzyl alcohol, benzene dimethanol, cinnamyl alcohol and some related carboxylic acids namely cinnamic acid, coumaric acid, and ferulic acid, was thus studied for assessing the ability of each additive to counteract chain scission of the polysaccharide and induce interchain covalent linkages. Gel formation in EB-irradiated blends comprising of maltodextrin was shown to be dependent on three main factors: the type of aromatic additive, presence of glycerol, and irradiation dose. The chain scission versus grafting phenomenon as a function of blend composition and dose were studied using Size Exclusion Chromatography by determining the changes in molecular weight distribution (MWD) from Refractive Index (RI) chromatograms and the presence of aromatic grafts onto the maltodextrin chains from UV chromatograms. The occurrence of crosslinking was quantified by gel fraction measurements allowing for ranking the cross-linking efficiency of the additives. When applying the method to destructurized starch blends, gel formation was also shown to be strongly affected by the moisture content of the sample submitted to irradiation. The results demonstrate the possibility to tune the reactivity of tailored blend for minimizing chain degradation and control the degree of cross-linking.
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Characterization of polycaprolactone and starch blends for potential ...
African Journals Online (AJOL)
Thermally blending starch and polycaprolactone with the compatibilizer methylenediphenyl diisocyanate (MDI) distributed in the polyester phase had been previously confirmed to enhance the mechanical properties and interface between the two phases of the blends. In this study, blends of polycaprolactone with various ...
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Blending effects on coal burnout and NO emissions
Energy Technology Data Exchange (ETDEWEB)
B. Arias; R. Backreedy; A. Arenillas; J.M. Jones; F. Rubiera; M. Pourkashanian; A. Williams; J.J. Pis [Instituto Nacional del Carbon, CSIC Oviedo (Spain)
2003-07-01
In this work, the combustion behaviour of individual coals of different rank and their blends was evaluated. The study was focused on burnout and NO emissions during blend combustion. Preliminary combustion tests of the coals and their blends were carried out in a thermogravimetric analyser (TGA). Some characteristic temperatures were obtained to evaluate the combustibility of the samples. These temperatures indicate an improvement in the combustibility of the less reactive coal when it is blended. An entrained flow reactor (EFR) was employed to study the behaviour of the samples at high heating rates and short residence times. Burnout and NO emissions were measured during EFR combustion tests. In some blends the results can be predicted from the weighted average of the values of the individual coals. However, other blends show an increase, from the averaged values, in burnout and especially in NO emissions. 14 refs., 10 figs., 3 tabs.
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BLENDED LEARNING COURSE FOR FUTURE PRIMARY SCHOOL TEACHERS IMPLEMENTATION
Directory of Open Access Journals (Sweden)
Vira V. Kotkova
2017-09-01
Full Text Available Ukrainian and foreign scientists’ views on the essence of blended learning are analyzed in the article. The author's definition of a blended learning course is presented. The process of such course designing is described according to target, motivational, substantive, operational and diagnostic components. Both the structure of the blended learning course implementation as well as students’ educational-cognitive activity distribution between classroom learning and distance course are shown. The problems for students, teachers, and educational institutions of blended courses effective implementation are summarized. Students’ academic performance of three years study is analyzed. The results of students’ questioning to determine their perception of blended learning course are described according to the following categories: the effectiveness of blended course, evaluation objectivity, motivation to study, the use of plagiarism in studies, understanding of blended learning course.
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Morphology development in immiscible polymer blends
Cardinaels, R.M.; Moldenaers, P.; Guo, Qipeng
This chapter discusses the morphology development of immiscible binary polymer blends. It first describes morphology development in droplet-matrix structures, the dynamics of fibrillar structures and cocontinuous structures. The chapter then considers binary immiscible polymer blends, such systems
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Directory of Open Access Journals (Sweden)
Zohreh Moghimi pour
2017-02-01
Full Text Available Introduction: Holy basil is a perennial plant belongs to Lamiaceae family. The plant is a perennial and thrives well in the hot and humid climate. Its aerial parts have been in use for food, pharmaceuticals, cosmetics and perfumery industries. Leaves contain 0.5-1.5% essential oil and main oil components are eugenol, methyl eugenol, carvacrol, methyl chavicol and1,8-cineole. A balanced fertilization program with macro and micronutrients is very important in producing high quality yield. Zinc is involved in IAA production, chlorophyll biosynthesis, carbon assimilation, saccharids accumulation, reactive oxygen radicals scavenging and finally carbon utilization in volatile oil biosynthesis. Material and methods: In order to evaluate the effect on zinc foliar application on zinc content of leaves, photosynthetic indices and pigments of holy basil, an experiment was carried out in 2013 at a research farm of Horticultural Science, Shahid Chamran University (31°20'N latitude and 48°40'E longitude and 22.5 m mean sea level, Ahvaz (Iran, a region characterized by semi-dry climate. The experiment was arranged based on Randomized Complete Block Design (RCBD with six treatments and three replications. The treatments were nano zinc chelate (0, 0.5, 1 and 1.5 g.l-1 and zinc sulfate (1 and 1.5 g.l-1 fertilizers. Land preparation includes disking and the formation of raising beds (15cm high and 45cm wide across the top using a press-pan-type bed shaper. Holy basil seeds were sown on two rows on each bed, with 15 cm in-row and 40 cm between-row spacing. The plants were irrigated weekly as needed. Foliar application of zinc fertilizers was done at six-eight leaf stage and were repeated with interval 15 days until full bloom stage. Zinc content, stomata conductance (gs, CO2 under stomata (Ci, transpiration rate (E, net photosynthesis (Pn, light use efficiency (LUE, water use efficiency (WUE and also chlorophyll a, chlorophyll b, chlorophyll a+b and carotenoid
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Cubic and quartic planar differential systems with exact algebraic limit cycles
Directory of Open Access Journals (Sweden)
Ahmed Bendjeddou
2011-01-01
Full Text Available We construct cubic and quartic polynomial planar differential systems with exact limit cycles that are ovals of algebraic real curves of degree four. The result obtained for the cubic case generalizes a proposition of [9]. For the quartic case, we deduce for the first time a class of systems with four algebraic limit cycles and another for which nested configurations of limit cycles occur.
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Synthesis of geopolymer from biomass-coal ash blends
Samadhi, Tjokorde Walmiki; Wulandari, Winny; Prasetyo, Muhammad Iqbal; Fernando, Muhammad Rizki; Purbasari, Aprilina
2017-09-01
Geopolymer is an environmentally attractive Portland cement substitute, owing to its lower carbon footprint and its ability to consume various aluminosilicate waste materials as its precursors. This work describes the development of geopolymer formulation based on biomass-coal ash blends, which is predicted to be the prevalent type of waste when biomass-based thermal energy production becomes mainstream in Indonesia. The ash blends contain an ASTM Class F coal fly ash (FA), rice husk ash (RHA), and coconut shell ash (CSA). A mixture of Na2SiO3 and concentrated KOH is used as the activator solution. A preliminary experiment identified the appropriate activator/ash mass ratio to be 2.0, while the activator Na2SiO3/KOH ratio varies from 0.8 to 2.0 with increasing ash blend Si/Al ratio. Both non-blended FA and CSA are able to produce geopolymer mortars with 7-day compressive strength exceeding the Indonesian national SNI 15-2049-2004 standard minimum value of 2.0 MPa stipulated for Portland cement mortars. Ash blends have to be formulated with a maximum RHA content of approximately 50 %-mass to yield satisfactory 7-day strength. No optimum ash blend composition is identified within the simplex ternary ash blend compositional region. The strength decreases with Si/Al ratio of the ash blends due to increasing amount of unreacted silicate raw materials at the end of the geopolymer hardening period. Overall, it is confirmed that CSA and blended RHA are feasible raw materials for geopolymer production..
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Conformal Interpolating Algorithm Based on Cubic NURBS in Aspheric Ultra-Precision Machining
International Nuclear Information System (INIS)
Li, C G; Zhang, Q R; Cao, C G; Zhao, S L
2006-01-01
Numeric control machining and on-line compensation for aspheric surface are key techniques in ultra-precision machining. In this paper, conformal cubic NURBS interpolating curve is applied to fit the character curve of aspheric surface. Its algorithm and process are also proposed and imitated by Matlab7.0 software. To evaluate the performance of the conformal cubic NURBS interpolation, we compare it with the linear interpolations. The result verifies this method can ensure smoothness of interpolating spline curve and preserve original shape characters. The surface quality interpolated by cubic NURBS is higher than by line. The algorithm is benefit to increasing the surface form precision of workpieces in ultra-precision machining
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Enzymatic degradation of polycaprolactone–gelatin blend
International Nuclear Information System (INIS)
Banerjee, Aditi; Chatterjee, Kaushik; Madras, Giridhar
2015-01-01
Blends of polycaprolactone (PCL), a synthetic polymer and gelatin, natural polymer offer a optimal combination of strength, water wettability and cytocompatibility for use as a resorbable biomaterial. The enzymatic degradation of PCL, gelatin and PCL–gelatin blended films was studied in the presence of lipase (Novozym 435, immobilized) and lysozyme. Novozym 435 degraded the PCL films whereas lysozyme degraded the gelatin. Though Novozym 435 and lysozyme individually could degrade PCL–gelatin blended films, the combination of these enzymes showed the highest degradation of these blended films. Moreover, the enzymatic degradation was much faster when fresh enzymes were added at regular intervals. The changes in physico-chemical properties of polymer films due to degradation were studied by scanning electron microscopy, Fourier transform infrared spectroscopy and differential scanning calorimetry. These results have important implications for designing resorbable biomedical implants. (paper)
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Deficiencia de zinc y sus implicaciones funcionales Zinc deficiency and its functional implications
Directory of Open Access Journals (Sweden)
JORGE L ROSADO
1998-03-01
Full Text Available El presente trabajo tiene por objeto revisar los aspectos teóricos y los estudios realizados en México que sugieren la existencia de la deficiencia moderada de zinc en niños de población rural, así como algunas de las consecuencias de dicha deficiencia en la salud. El zinc es un nutrimento indispensable para el organismo de los humanos y juega un papel importante en una serie de procesos metabólicos: participa en el sitio catalítico de varios sistemas enzimáticos; participa como ion estructural en membranas biológicas, y guarda una estrecha relación con la síntesis de proteínas, entre otras cosas. Es por esto que la deficiencia de zinc está asociada con consecuencias importantes en la salud y la funcionalidad de los individuos, especialmente durante las primeras etapas de la vida. De relevancia para México es la existencia de una deficiencia moderada de zinc en los niños y las consecuencias que ésta pueda tener en la salud de los mismos. Los estudios realizados sugieren que la deficiencia moderada de zinc se presenta asociada con la ingestión de dietas basadas en alimentos de origen vegetal, las cuales contienen cantidades importantes de inhibidores de la absorción de zinc. Este tipo de dietas se consume habitualmente en las zonas rurales y en la población marginal de las ciudades en el país. Entre las consecuencias más importantes de esta deficiencia se encontró un aumento en la presencia de enfermedades infecciosas, especialmente de diarrea, y posibles alteraciones en el desarrollo de la capacidad cognoscitiva.The purpose of this article is to review theoretical aspects and research performed in Mexico suggesting the existence of marginal zinc deficiency in rural children and its consequences on health. Zinc is an indispensable nutrient for humans since it plays an important role in several metabolic pathways: it participates in the catalytic site of several enzymes, as a structural ion of biological membranes and is
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International Nuclear Information System (INIS)
Bonnet, J.; Bounor-Legaré, V.; Alcouffe, P.; Cassagnau, P.
2012-01-01
A new and original method based on carbonyl hydrosilylation was developed to prepare ethylene-vinyl acetate (EVA)/polysiloxane polymer blends. This focused on the addition of hydrogenosilane groups (SiH) from polysiloxane to the carbonyl groups of EVA. The influence of the nature of the polysiloxane on blend properties was investigated by rheology and scanning electron microscopy. Mixing of a low viscosity polysiloxane with a high viscosity EVA matrix produced a two-phase morphology. The occurrence of the hydrosilylation reaction at the EVA/polysiloxane interface promoted a homogenisation of the blend depending on the molar ratio SiH/vinyl acetate groups, [SiH]/[VA], and the viscosity ratio of the blend. Two distinct behaviours were observed. The formation of a crosslinked network under shear was obtained for a low viscosity ratio between polysiloxane and EVA (λ polysiloxane/EVA = 4.0 × 10 −6 ) with a high concentration of SiH groups ([SiH]/[VA] = 0.5), while the formation of a compatibilised blend was observed for high molar mass polysiloxanes (Mn > 15,000 g mol −1 ) with a low concentration of SiH ([SiH]/[VA] −3 ). -- Highlights: ► Carbonyl hydrosilylation reaction was found to enhance EVA/polysiloxane immiscible blends. ► EVA crosslinking was obtained with a low molar mass polysiloxane. ► EVA compatibilisation was obtained with a high molar mass polysiloxane. ► Shear rate was found to improve the hydrosilylation reaction at the interface. ► A two-phase morphology of the blends was observed after reaction with fine polysiloxane nodules.
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Zinc in Infection and Inflammation
Directory of Open Access Journals (Sweden)
Nour Zahi Gammoh
2017-06-01
Full Text Available Micronutrient homeostasis is a key factor in maintaining a healthy immune system. Zinc is an essential micronutrient that is involved in the regulation of the innate and adaptive immune responses. The main cause of zinc deficiency is malnutrition. Zinc deficiency leads to cell-mediated immune dysfunctions among other manifestations. Consequently, such dysfunctions lead to a worse outcome in the response towards bacterial infection and sepsis. For instance, zinc is an essential component of the pathogen-eliminating signal transduction pathways leading to neutrophil extracellular traps (NET formation, as well as inducing cell-mediated immunity over humoral immunity by regulating specific factors of differentiation. Additionally, zinc deficiency plays a role in inflammation, mainly elevating inflammatory response as well as damage to host tissue. Zinc is involved in the modulation of the proinflammatory response by targeting Nuclear Factor Kappa B (NF-κB, a transcription factor that is the master regulator of proinflammatory responses. It is also involved in controlling oxidative stress and regulating inflammatory cytokines. Zinc plays an intricate function during an immune response and its homeostasis is critical for sustaining proper immune function. This review will summarize the latest findings concerning the role of this micronutrient during the course of infections and inflammatory response and how the immune system modulates zinc depending on different stimuli.
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Daaboul, Doha; Rosenkranz, Eva; Uciechowski, Peter; Rink, Lothar
2012-10-01
Mild zinc deficiency in humans negatively affects IL-2 production resulting in declined percentages of cytolytic T cells and decreased NK cell lytic activity, which enhances the susceptibility to infections and malignancies. T-cell activation is critically regulated by zinc and the normal physiological zinc level in T-cells slightly lies below the optimal concentration for T-cell functions. A further reduction in zinc level leads to T-cell dysfunction and autoreactivity, whereas high zinc concentrations (100 μM) were shown to inhibit interleukin-1 (IL-1)-induced IL-1 receptor kinase (IRAK) activation. In this study, we investigated the molecular mechanism by which zinc regulates the IL-1β-induced IL-2 expression in T-cells. Zinc supplementation to zinc-deficient T-cells increased intracellular zinc levels by altering the expression of zinc transporters, particularly Zip10 and Zip12. A zinc signal was observed in the murine T-cell line EL-4 6.1 after 1 h of stimulation with IL-1β, measured by specific zinc sensors FluoZin-3 and ZinPyr-1. This signal is required for the phosphorylation of MAPK p38 and NF-κB subunit p65, which triggers the transcription of IL-2 and strongly increases its production. These results indicate that short-term zinc supplementation to zinc-deficient T-cells leads to a fast rise in zinc levels which subsequently enhance cytokine production. In conclusion, low and excessive zinc levels might be equally problematic for zinc-deficient subjects, and stabilized zinc levels seem to be essential to avoid negative concentration-dependent zinc effects on T-cell activation.
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The study and microstructure analysis of zinc and zinc oxide
Directory of Open Access Journals (Sweden)
N. Luptáková
2015-01-01
Full Text Available The given paper is closely connected with the process of the manufacturing of ZnO. The purity of the metal zinc has crucial influence on the quality of ZnO. ZnO can be produced by pyrometallurgical combustion of zinc and hard zinc. But this mentioned method of preparation leads to the creation of the enormous amount of waste including chemical complexes. On the basis of the occurrence of the residual content of other elements, it is possible to make prediction about the material behavior in the metallographic process. The input and finally materials were investigated and this investigation was done from the aspect of structural and chemical composition of the materials.
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BioBlend.objects: metacomputing with Galaxy.
Leo, Simone; Pireddu, Luca; Cuccuru, Gianmauro; Lianas, Luca; Soranzo, Nicola; Afgan, Enis; Zanetti, Gianluigi
2014-10-01
BioBlend.objects is a new component of the BioBlend package, adding an object-oriented interface for the Galaxy REST-based application programming interface. It improves support for metacomputing on Galaxy entities by providing higher-level functionality and allowing users to more easily create programs to explore, query and create Galaxy datasets and workflows. BioBlend.objects is available online at https://github.com/afgane/bioblend. The new object-oriented API is implemented by the galaxy/objects subpackage. © The Author 2014. Published by Oxford University Press.
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Game innovation through conceptual blending
DEFF Research Database (Denmark)
Möring, Sebastian Martin
In this paper I wish to apply implications of the Conceptual Blending Theory to computer games. I will analyze chosen examples and discuss them as a result of video game innovation made possible through "conceptual blending." Conceptual blending links at least......., Hell. The purpose of my approach is not so much to validate the ideas of conceptual blending theory through another field of examples (computer games) but to name and analyze characteristics of the mentioned games with the help of a given method....... integration network consisting of at least two input spaces, a generic space and a blended space as well as its governing principles consisting of composition, completion, and elaboration. With the help of these instruments I analyze computer games like Tuper Tario Tros...
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Cathodic hydrogen charging of zinc
International Nuclear Information System (INIS)
Panagopoulos, C.N.; Georgiou, E.P.; Chaliampalias, D.
2014-01-01
Highlights: •Incorporation of hydrogen into zinc and formation of zinc hydrides. •Investigation of surface residual stresses due to hydrogen diffusion. •Effect of hydrogen diffusion and hydride formation on mechanical properties of Zn. •Hydrogen embrittlement phenomena in zinc. -- Abstract: The effect of cathodic hydrogen charging on the structural and mechanical characteristics of zinc was investigated. Hardening of the surface layers of zinc, due to hydrogen incorporation and possible formation of ZnH 2 , was observed. In addition, the residual stresses brought about by the incorporation of hydrogen atoms into the metallic matrix, were calculated by analyzing the obtained X-ray diffraction patterns. Tensile testing of the as-received and hydrogen charged specimens revealed that the ductility of zinc decreased significantly with increasing hydrogen charging time, for a constant value of charging current density, and with increasing charging current density, for a constant value of charging time. However, the ultimate tensile strength of this material was slightly affected by the hydrogen charging procedure. The cathodically charged zinc exhibited brittle transgranular fracture at the surface layers and ductile intergranular fracture at the deeper layers of the material
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Dipaths and dihomotopies in a cubical complex
DEFF Research Database (Denmark)
Fajstrup, Lisbeth
2005-01-01
In the geometric realization of a cubical complex without degeneracies, a $\\Box$-set, dipaths and dihomotopies may not be combinatorial, i.e., not geometric realizations of combinatorial dipaths and equivalences. When we want to use geometric/topological tools to classify dipaths on the 1-skeleton...
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A study of coal-solid waste blend reactivity
Directory of Open Access Journals (Sweden)
Nayibe Guerrero
2008-05-01
Full Text Available The Flynn-Wall-Ozawa method was used for analysing coal-solid waste blend reactivity in an oxidising atmosphere. The presence of biomass strongly affected coal combustion kinetics when the blend contained more than 30% of it. Activation energy values (evaluated by different blends were 28.7495 kJ/mol for 0% biomass, 31.3915 kJ/mol for 30% biomass, 39.0365 kJ/mol for 50% biomass, 102.431 kJ/mol for 70% biomass and 107.8075 kJ/mol for 100% biomass; these values were close to those reported in the literature. First-order kinetics correlated the data ve-ry well for the 100% coal sample and the blend having 30% biomass and 70% coal. Eighth-order kinetics were more suitable for correlating the experimental data for the 70% biomass-30% coal blend and the 100% biomass sample. Combustion was done without previous pyrolysis of the blends; however segregation of phenomena could be appre-ciated. This seems to indicate that combustion and devolatilisation are independent processes which should be taken into account when building equipment using these kinds of blend.
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Production of silk sericin/silk fibroin blend nanofibers
Directory of Open Access Journals (Sweden)
Zhang Xianhua
2011-01-01
Full Text Available Abstract Silk sericin (SS/silk fibroin (SF blend nanofibers have been produced by electrospinning in a binary SS/SF trifluoroacetic acid (TFA solution system, which was prepared by mixing 20 wt.% SS TFA solution and 10 wt.% SF TFA solution to give different compositions. The diameters of the SS/SF nanofibers ranged from 33 to 837 nm, and they showed a round cross section. The surface of the SS/SF nanofibers was smooth, and the fibers possessed a bead-free structure. The average diameters of the SS/SF (75/25, 50/50, and 25/75 blend nanofibers were much thicker than that of SS and SF nanofibers. The SS/SF (100/0, 75/25, and 50/50 blend nanofibers were easily dissolved in water, while the SS/SF (25/75 and 0/100 blend nanofibers could not be completely dissolved in water. The SS/SF blend nanofibers could not be completely dissolved in methanol. The SS/SF blend nanofibers were characterized by Fourier transform infrared (FTIR spectroscopy, differential scanning calorimetry, and differential thermal analysis. FTIR showed that the SS/SF blend nanofibers possessed a random coil conformation and ß-sheet structure.
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Kim, D.; Lee, C.; Jeong, S.
2018-01-01
In this study, a concentrated electrolyte was applied in an aqueous rechargeable zinc-ion battery system with a zinc hexacyanoferrate (ZnHCF) electrode to improve the electrochemical performance by changing the hydration number of the zinc ions. To optimize the active material, ZnHCF was synthesized using aqueous solutions of zinc nitrate with three different concentrations. The synthesized materials exhibited some differences in structure, crystallinity, and particle size, as observed by X-ray diffraction and scanning electron microscopy. Subsequently, these well-structured materials were applied in electrochemical tests. A more than two-fold improvement in the charge/discharge capacities was observed when the concentrated electrolyte was used instead of the dilute electrolyte. Additionally, the cycling performance observed in the concentrated electrolyte was superior to that in the dilute electrolyte. This improvement in the electrochemical performance may result from a decrease in the hydration number of the zinc ions in the concentrated electrolyte.
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Zinc-mediated Allosteric Inhibition of Caspase-6*
Velázquez-Delgado, Elih M.; Hardy, Jeanne A.
2012-01-01
Zinc and caspase-6 have independently been implicated in several neurodegenerative disorders. Depletion of zinc intracellularly leads to apoptosis by an unknown mechanism. Zinc inhibits cysteine proteases, including the apoptotic caspases, leading to the hypothesis that zinc-mediated inhibition of caspase-6 might contribute to its regulation in a neurodegenerative context. Using inductively coupled plasma optical emission spectroscopy, we observed that caspase-6 binds one zinc per monomer, under the same conditions where the zinc leads to complete loss of enzymatic activity. To understand the molecular details of zinc binding and inhibition, we performed an anomalous diffraction experiment above the zinc edge. The anomalous difference maps showed strong 5σ peaks, indicating the presence of one zinc/monomer bound at an exosite distal from the active site. Zinc was not observed bound to the active site. The zinc in the exosite was liganded by Lys-36, Glu-244, and His-287 with a water molecule serving as the fourth ligand, forming a distorted tetrahedral ligation sphere. This exosite appears to be unique to caspase-6, as the residues involved in zinc binding were not conserved across the caspase family. Our data suggest that binding of zinc at the exosite is the primary route of inhibition, potentially locking caspase-6 into the inactive helical conformation. PMID:22891250
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Blended Learning as Transformational Institutional Learning
VanDerLinden, Kim
2014-01-01
This chapter reviews institutional approaches to blended learning and the ways in which institutions support faculty in the intentional redesign of courses to produce optimal learning. The chapter positions blended learning as a strategic opportunity to engage in organizational learning.
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Environmental risk limits for zinc
Bodar CWM; SEC
2007-01-01
Environmental Riks Limits (ERLs) were derived for zinc. ERLs serve as advisory values to set environmental quality standards in the Netherlands. The ERLs for zinc closely follow the outcomes of earlier discussions on zinc within the Water Framework Directive and EC Regulation 793/93. The ERLs
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Environmental risk limits for zinc
Bodar CWM; SEC
2007-01-01
Environmental Riks Limits (ERLs) were derived for zinc. ERLs serve as advisory values to set environmental quality standards in the Netherlands. The ERLs for zinc closely follow the outcomes of earlier discussions on zinc within the Water Framework Directive and EC Regulation 793/93. The ERLs refer
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Zhang, Ling; Niu, Wenxin; Zhao, Jianming; Zhu, Shuyun; Yuan, Yali; Hua, Lianzhe; Xu, Guobao
2013-01-01
A new type of concave cubic Pd@Au core-shell nanocrystals is synthesized through a kinetically controlled growth process. Pd nanocubes of 56 nm are used as the inner core, and CTAC and Br(-) are used as the capping agent and selective adsorbent, respectively. A suitable ratio of HAuCl4 and cubic Pd seeds and the presence of Br(-) anions are critical to the growth of the concave cubic Pd@Au core-shell nanocrystals. The fast deposition rate on the corners of the cubic Pd seeds promotes the overgrowth of the Au outer shell along the direction, leading to the formation of concave cubic nanostructures. The reduction process is monitored by the surface plasmon resonance spectra of the nanocrystals, and the extinction band became broader and red shifted as the nanocrystals became larger. The electrocatalytic properties of the concave cubic Pd@Au core-shell nanocrystals were investigated with the cathodic electrochemiluminescence reaction of luminol and H2O2. A possible electrocatalytic mechanism was proposed and analyzed.
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Blended Learning within an Undergraduate Exercise Physiology Laboratory
Elmer, Steven J.; Carter, Kathryn R.; Armga, Austin J.; Carter, Jason R.
2016-01-01
In physiological education, blended course formats (integration of face-to-face and online instruction) can facilitate increased student learning, performance, and satisfaction in classroom settings. There is limited evidence on the effectiveness of using blending course formats in laboratory settings. We evaluated the impact of blended learning…
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Zinc-The key to preventing corrosion
Kropschot, S.J.; Doebrich, Jeff L.
2011-01-01
Centuries before it was identified as an element, zinc was used to make brass (an alloy of zinc and copper) and for medicinal purposes. Metallic zinc and zinc oxide were produced in India sometime between the 11th and 14th centuries and in China in the 17th century, although the discovery of pure metallic zinc is credited to the German chemist Andreas Marggraf, who isolated the element in 1746. Refined zinc metal is bluish-white when freshly cast; it is hard and brittle at most temperatures and has relatively low melting and boiling points. Zinc alloys readily with other metals and is chemically active. On exposure to air, it develops a thin gray oxide film (patina), which inhibits deeper oxidation (corrosion) of the metal. The metal's resistance to corrosion is an important characteristic in its use.
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Potential Application of ENR/EPDM Blends
Directory of Open Access Journals (Sweden)
B.L. Chan
2017-06-01
Full Text Available Since the process and conversion of natural rubber into epoxidized natural rubber (ENR was discovered and patented by I. R. Gelling of the Malaysian Rubber Product Research Association (or now known as the Tun Razak laboratory, Brickendonbury, Hertford, in the United Kingdom, there are more than 10 000 technical and technological papers cited in the internet. Information on ENR is available, not only in the the English language but also other languages like Chinese, Malay, French, Thai and even German languages are used. NR is the most versatile and reactive rubber/elastomer. It is an advanced natural rubber which could be potentially used as a starting material for the development of other rubbers, modifie elastomers, for grafting, plastic-based materials and also thermoplastic rubbers. Its reactivity is dependent on its epoxy groups, the opening of its ring structure, and also the subsequent structures of carboxylic groups and the in-situ side-chains “carbon – carbon” double bonds (> C = C <. In some instances, up to 65% epoxidation of NR is possible and achieved for more oil resistance. For these reasons, there are many new and advanced materials which have been formed and developed in the last two decades. Among them, some of the recent research work is listed here. Apart from studies of compounding the ENR itself and its potential uses, there are many rubber-rubber blends and ENR rubber-plastics blends, some of the studies cited are “uses of new and advanced chemicals” and synthetic rubbers: ENR/NBR, ENR/PVC, ENR/polylactic acid blends, ENR/copolyester blends, ENR/Copolyamide Blends, ENR/poly (vinylidene fluorideblends, ENR/Carbon Nanotubes with co-agent Trimethylol Propane Triacrylate, ENR /recycled silicon materials, and ENR/copolymer of n-butyl acrylate/butyl methacrylate “grafted”. Each of these blends has its own characteristics in terms of processing, enhancement of processing like safety, scorch, oil and water
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Teaching of anatomical sciences: A blended learning approach.
Khalil, Mohammed K; Abdel Meguid, Eiman M; Elkhider, Ihsan A
2018-04-01
Blended learning is the integration of different learning approaches, new technologies, and activities that combine traditional face-to-face teaching methods with authentic online methodologies. Although advances in educational technology have helped to expand the selection of different pedagogies, the teaching of anatomical sciences has been challenged by implementation difficulties and other limitations. These challenges are reported to include lack of time, costs, and lack of qualified teachers. Easy access to online information and advances in technology make it possible to resolve these limitations by adopting blended learning approaches. Blended learning strategies have been shown to improve students' academic performance, motivation, attitude, and satisfaction, and to provide convenient and flexible learning. Implementation of blended learning strategies has also proved cost effective. This article provides a theoretical foundation for blended learning and proposes a validated framework for the design of blended learning activities in the teaching and learning of anatomical sciences. Clin. Anat. 31:323-329, 2018. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.
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Yazbeck, Nadine; Hanna-Wakim, Rima; El Rafei, Rym; Barhoumi, Abir; Farra, Chantal; Daher, Rose T; Majdalani, Marianne
2016-01-01
The burden of zinc deficiency on children includes an increased incidence of diarrhea, failure to thrive (FTT) and short stature. The aim of this study was to assess whether children with FTT and/or short stature have lower dietary zinc intake and plasma zinc concentrations compared to controls. A case-control study conducted at the American University of Beirut Medical Center included 161 subjects from 1 to 10 years of age. Cases had a statistically significant lower energy intake (960.9 vs. 1,135.2 kcal for controls, p = 0.010), lower level of fat (30.3 vs. 36.5 g/day, p = 0.0043) and iron intake (7.4 vs. 9.1 mg/day, p = 0.034). There was no difference in zinc, copper, carbohydrate and protein intake between the 2 groups. The plasma zinc concentration did not differ between the cases and controls (97.4 vs. 98.2 μg/dl, p = 0.882). More cases had mild-to-moderate zinc deficiency when compared to controls with 10.3 vs. 3.6%, p = 0.095. Our study did not show statistically significant difference in dietary zinc intake and plasma zinc concentrations between children with FTT and/or short stature compared to healthy controls. A prospective study is planned to assess the effect of zinc supplementation on growth parameters in FTT children. © 2016 S. Karger AG, Basel.
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Compton profiles and band structure calculations of CdS and CdTe
International Nuclear Information System (INIS)
Heda, N.L.; Mathur, S.; Ahuja, B.L.; Sharma, B.K.
2007-01-01
In this paper we present the isotropic Compton profiles of zinc-blende CdS and CdTe measured at an intermediate resolution of 0.39 a.u. using our 20 Ci 137 Cs Compton spectrometer. The electronic band structure calculations for both the zinc-blende structure compounds and also wurtzite CdS have been undertaken using various schemes of ab-initio linear combination of atomic orbitals calculations implemented in CRYSTAL03 code. The band structure and Mulliken's populations are reported using density functional scheme. In case of wurtzite CdS, our theoretical anisotropies in directional Compton profiles are compared with available experimental data. In case of both the zinc-blende compounds, the isotropic experimental profiles are found to be in better agreement with the present Hartree-Fock calculations. A study of the equal-valence-electron-density experimental profiles of zinc-blende CdS and CdTe shows that the CdS is more ionic than CdTe. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)
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Radioactive zinc in soil-plant relationship studies
International Nuclear Information System (INIS)
Karimian, N.
1986-01-01
Zinc is one of the elements whose essentiality for plant growth and development has been proved beyond any doubt. Plant life and consequently the crop yield is impossible without zinc. The results of chemical, greenhouse, and field experiments on soils of Shiraz show that their level of available zinc for some crops is inadequate, despite the fact that the total amount of zinc in these soils may be relatively high. Obtaining the maximum yield, therefore, requires that either supplemental zinc be applied as chemical fertilizers or make the endogenous zinc more available to plants through some management practices. One of the isotopes of zinc, i.e. 65 Zn, is radioactive and has a detectable radiation which makes it suitable for tracer studies of zinc in soil, water, plant and animal. These studies help in understanding the soil plant relationships of zinc which in turn help to determine the optimum conditions of obtaining maximum yield. This paper presents and analyzes the results of some selected experiments to show different techniques of using radioactive zinc in understanding the behavior of zinc in soil and plant. Suggestions are also made of using this radioisotope in understanding the reactions of zinc in soils of Iran
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Saritaş, Sevda; Ceviz Sakar, Betul; Kundakci, Mutlu; Yildirim, Muhammet
2018-06-01
Iron oxide thin films have been obtained significant interest as a material that put forwards applications in photovoltaics, gas sensors, biosensors, optoelectronic and especially in spintronics. Iron oxide is one of the considerable interest due to its chemical and thermal stability. Metallic ion dopant influenced superexchange interactions and thus changed the structural, electrical and magnetic properties of the thin film. Mg dopped zinc ferrite (Mg:ZnxFe3-xO4) crystal was used to avoid the damage of Fe3O4 (magnetite) crystal instead of Zn2+ in this study. Because the radius of the Mg2+ ion in the A-site (tetrahedral) is almost equal to that of the replaced Fe3+ ion. Inverse-spinel structure in which oxygen ions (O2-) are arranged to form a face-centered cubic (FCC) lattice where there are two kinds of sublattices, namely, A-site and B-site (octahedral) interstitial sites and in which the super exchange interactions occur. In this study, to increase the saturation of magnetization (Ms) value for iron oxide, inverse-spinal ferrite materials have been prepared, in which the iron oxide was doped by multifarious divalent metallic elements including Zn and Mg. Triple and quaternary; iron oxide and zinc ferrite thin films with Mg metal dopants were grown by using Spray Pyrolysis (SP) technique. The structural, electrical and magnetic properties of Mg dopped iron oxide (Fe2O3) and zinc ferrite (ZnxFe3-xO4) thin films have been investigated. Vibrating Sample Magnetometer (VSM) technique was used to study for the magnetic properties. As a result, we can say that Mg dopped iron oxide thin film has huge diamagnetic and of Mg dopped zinc ferrite thin film has paramagnetic property at bigger magnetic field.
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The effect of oral zinc loading on the absorption of 65Zinc in the rat
International Nuclear Information System (INIS)
Hoyer, H.; Weismann, K.
1979-01-01
Seven groups of 8 rats each were orally loaded with zinc, the daily dose varying from 1.8 to 58 mg, corresponding to about 3 to 100 times of their estimated daily intake of zinc. To record the absorption of zinc, the rats were given a single dose of 65 Zn. The rentention of the isotope was measured in a whole animal counter at regular intervals. The dose of 58mg was obviously toxis, since half of the animals died within 5 days. The net absorption of zinc in the remaining experimental groups was found to vary from about 7% in the group receiving the smallest loading dose to 1.8% in the group receiving the highest dose. From the absorption values, as determined by extrapolation of semilog retention curves, the total amount of absorbed zinc was estimated. It was found to differ from about 170μg to about 530μg zinc daily, increasing three times as the loading dose was increased 16 times. This discrepancy suggests the existence of regulatory mechanisms of the absorption of zinc from the intestine. (orig.) [de
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Medicago truncatula Zinc-Iron Permease6 provides zinc to rhizobia-infected nodule cells.
Abreu, Isidro; Saéz, Ángela; Castro-Rodríguez, Rosario; Escudero, Viviana; Rodríguez-Haas, Benjamín; Senovilla, Marta; Larue, Camille; Grolimund, Daniel; Tejada-Jiménez, Manuel; Imperial, Juan; González-Guerrero, Manuel
2017-11-01
Zinc is a micronutrient required for symbiotic nitrogen fixation. It has been proposed that in model legume Medicago truncatula, zinc is delivered by the root vasculature into the nodule and released in the infection/differentiation zone. There, transporters must introduce this element into rhizobia-infected cells to metallate the apoproteins that use zinc as a cofactor. MtZIP6 (Medtr4g083570) is an M. truncatula Zinc-Iron Permease (ZIP) that is expressed only in roots and nodules, with the highest expression levels in the infection/differentiation zone. Immunolocalization studies indicate that it is located in the plasma membrane of nodule rhizobia-infected cells. Down-regulating MtZIP6 expression levels with RNAi does not result in any strong phenotype when plants are fed mineral nitrogen. However, these plants displayed severe growth defects when they depended on nitrogen fixed by their nodules, losing of 80% of their nitrogenase activity. The reduction of this activity was likely an indirect effect of zinc being retained in the infection/differentiation zone and not reaching the cytosol of rhizobia-infected cells. These data are consistent with a model in which MtZIP6 would be responsible for zinc uptake by rhizobia-infected nodule cells in the infection/differentiation zone. © 2017 John Wiley & Sons Ltd.
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Polymer blends of polylactic acid (PLA) and polybutylene succinate-adipate
Ma, Wenguang
A series of blends consisting of polylactic acid (PLA) and aliphatic succinate polyester (BionolleRTM #3000) had been prepared and investigated. The results of mechanical property investigations showed that using 20 wt% Bionolle#3000 can significantly increase the toughness of PLA. BionolleRTM #3000 also reduces the physical aging rate of PLA so blends remain tough longer. Conversely, the stiffness of BionolleRTM #3000 can be significantly increased by blending in PLA. DMA and DSC results show that PLA/BionolleRTM 3000 blends are not thermodynamically miscible, but are compatible blends. Studies have also been performed to determine the amount and rate of aerobic biodegradation of PLA/aliphatic succinate polyester blends in biologically active composting, enzymatic, and soil environments. The changes in molecular weight, molecular structure and thermal properties in the composting environment were also studied by GPC, NMR and DSC analyses. The research results showed BionolleRTM #3000 had a high degradation rate, while PLA had a low degradation rate. PLA/BionolleRTM #3000 blends had moderate degradation rates that increased with BionolleRTM #3000 content. The melt flow behavior of PLA/BionolleRTM #3000 blends has been studied by capillary rheometry. The relationship of the blends' viscosity with their composition, shear stress, shear rate, and temperature has been investigated. Power law index and activation energy of PLA, BionolleRTM #3000 and their blends have been calculated. The experimental and theoretical data can let us understand the processability of PLA/BionolleRTM #3000 blends. A scanning electron microscope (SEM) was used to investigate the morphological structure of the PLA/BionolleRTM #3000 blends. Micrographs of the samples made from different methods (blown film, extrudate and compression molding sheet) were taken; their differences in morphology were compared. For comparison, the micrographs of blend PLA/BionolleRTM #6000 was also studied. The
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Finding a balance in dimensions of blended learning
Verkroost, M.; Meijerink, L.; Lintsen, H.W.; Veen, W.
2008-01-01
This article is a formative evaluation of a course in which a blended learning environment was created and a good balance in dimensions of blended learning was sought. Blended learning is defined as the total mix of pedagogical methods, using a combination of different learning strategies, both with
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Effect of bismuth ion substitution on structural properties of zinc ferrite nanoparticles
Directory of Open Access Journals (Sweden)
Naraavula Suresh Kumar
2016-06-01
Full Text Available Bismuth doped nano zinc ferrite particles having the general formula ZnFe2-xBixO4 (x = 0.00, 0.05, 0.10, 0.15, 0.20 and 0.25 were synthesized by sol-gel combustion method. The effect of bismuth doping on structural properties were investigated. The X-ray diffraction (XRD spectra confirm the single phase cubic spinel structure. The average crystallite sizes of all the samples were determined by Debye-Scherrer equation and are in the range 16–20 nm. The lattice parameter increases with the increase of bismuth ion concentration. This is due to the larger ionic radius of Bi3+ ions substituting smaller Fe3+ ions at octahedral sites (B-sites. The surface morphology of all compounds was studied by scanning electron microscope (SEM. The microstructure analysis and the particle size were examined by transmission electron microscope (TEM. The compositional stoichiometry of these samples was verified by energy dispersive spectroscopy (EDS analysis.
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Zhang, Ye; Hao, Yuying; Meng, Weixin; Xu, Huixia; Wang, Hua; Xu, Bingshe
2012-03-01
The electroplex between (2-(4-trifluoromethyl-2-hydroxyphenyl)benzothiazole) zinc [Zn(4-TfmBTZ)2] as an electron-acceptor and N,N'-diphenyl-N,N'-bis(1-naphthyl)-(1,1'-biphenyl)-4,4'-diamine (NPB) as an electron-donor was characterized by bilayer, blend, and multilayer quantum-well (MQW) device, respectively. The blend composition and quantum-well number are effective parameters for tuning electroluminescence color. White light with high color purity and color rendering index (CRI) was observed from these devices based on Zn(4-TfmBTZ)2/NPB. Moreover, the blend and MQW devices all exhibit high operation stability, hence excellent color stability. For the device with 5 mol% NPB in blend layer, its Commission International Del'Eclairage (CIE) coordinate region is x=0.28-0.31, y=0.33-0.35 and CRI is 83.3-91.2 at 5-9 V. For MQW structure device with NPB of 60 nm thickness, its CIE coordinate region is x=0.29-0.32, y=0.31-0.34 and CRI=87.9-92.5 at 10-15 V. Such high color stability and purity and CRI, being close to ideal white light, are of current important for white OLED.
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NOx emissions and combustibility characteristics of coal blends
Energy Technology Data Exchange (ETDEWEB)
Rubiera, F.; Arenillas, A.; Arias, B.; Pis, J.J. [CSIC, Instituto Nacional del Carbon, Oviedo (Spain). Dept. of Energy and Environment
2001-07-01
In this work, a series of coals with different origin and rank were blended and several aspects of the resultant blends were studied. This included determination of the grindability of individual coals and blends by means of the Hardgrove Grindability Index (HGI), and temperature programmed combustion test, which were carried out in a thermogravimetric analyser (TG) coupled to a quadruple mass spectrometer (MS) for evolved gas analysis. Special attention was paid to the combustibility parameters and the NO emissions during blends combustion. It was found that while some coal blends present interaction between the individual coals, others do not. This behaviour was assumed to be due to the differences in coal structure and functional groups composition. 18 refs., 11 figs., 2 tabs.
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On The compatibility and dynamic vulcanization of Pom/Nbr blends
International Nuclear Information System (INIS)
Mortezaee, M.; Naveed Family, M.H.; Mehrabzadeh, M.
2001-01-01
Polymer blends based on polyacetal butadiene rubber were prepared by melt blending technique. The mixing parameters such ad temperature, time and speed of mixing were varied to obtain a wide range of properties. The mixing parameters were optimized by evaluating the mechanical properties of the blend over a wide range of mixing conditions. The morphology of the blend indicated a two-phase structure. This study describes an attempt to improve the tensile strength of Pom/Nbr blends by means of compatibility and dynamic vulcanization. A commercial compatibility, maleic anhydride (Ma), has been used to control the phase morphology of the blend system. Dicumyl peroxide is used to dynamically vulcanize the Nbr elastomer in the blend. The tensile strength of the compatibility systems showed improvement. Dynamic vulcanization raises elastic recovery and tensile modulus of the blends, but the elongation at break decreases
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3D confocal imaging in CUBIC-cleared mouse heart
Energy Technology Data Exchange (ETDEWEB)
Nehrhoff, I.; Bocancea, D.; Vaquero, J.; Vaquero, J.J.; Lorrio, M.T.; Ripoll, J.; Desco, M.; Gomez-Gaviro, M.V.
2016-07-01
Acquiring high resolution 3D images of the heart enables the ability to study heart diseases more in detail. Here, the CUBIC (clear, unobstructed brain imaging cocktails and computational analysis) clearing protocol was adapted for thick mouse heart sections to increase the penetration depth of the confocal microscope lasers into the tissue. The adapted CUBIC clearing of the heart lets the antibody penetrate deeper into the tissue by a factor of five. The here shown protocol enables deep 3D highresolution image acquisition in the heart. This allows a much more accurate assessment of the cellular and structural changes that underlie heart diseases. (Author)
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Eisenstein Series Identities Involving the Borweins' Cubic Theta Functions
Directory of Open Access Journals (Sweden)
Ernest X. W. Xia
2012-01-01
Full Text Available Based on the theories of Ramanujan's elliptic functions and the (p, k-parametrization of theta functions due to Alaca et al. (2006, 2007, 2006 we derive certain Eisenstein series identities involving the Borweins' cubic theta functions with the help of the computer. Some of these identities were proved by Liu based on the fundamental theory of elliptic functions and some of them may be new. One side of each identity involves Eisenstein series, the other products of the Borweins' cubic theta functions. As applications, we evaluate some convolution sums. These evaluations are different from the formulas given by Alaca et al.
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3D confocal imaging in CUBIC-cleared mouse heart
International Nuclear Information System (INIS)
Nehrhoff, I.; Bocancea, D.; Vaquero, J.; Vaquero, J.J.; Lorrio, M.T.; Ripoll, J.; Desco, M.; Gomez-Gaviro, M.V.
2016-01-01
Acquiring high resolution 3D images of the heart enables the ability to study heart diseases more in detail. Here, the CUBIC (clear, unobstructed brain imaging cocktails and computational analysis) clearing protocol was adapted for thick mouse heart sections to increase the penetration depth of the confocal microscope lasers into the tissue. The adapted CUBIC clearing of the heart lets the antibody penetrate deeper into the tissue by a factor of five. The here shown protocol enables deep 3D highresolution image acquisition in the heart. This allows a much more accurate assessment of the cellular and structural changes that underlie heart diseases. (Author)
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Baghaie, Shaghayegh; Khorasani, Mohammad T; Zarrabi, Ali; Moshtaghian, Jamal
2017-12-01
In this work, hydrogel membranes were developed based on poly vinyl alcohol (PVA), starch (St), and chitosan (Cs) hydrogels with nano Zinc oxide (nZnO). PVA/St/Cs/nZnO hydrogel membranes were prepared by freezing-thawing cycles, and the aqueous PVA/St solutions were prepared by dissolving PVA in distilled water. After the dissolution of PVA, starch was mixed, and the mixture was stirred. Then, chitosan powder was added into acetic acid, and the mixture was stirred to form a chitosan solution. Subsequently, Cs, St and PVA solutions were blended together to form a homogeneous PVA/St/Cs ternary blend solution. Measurement of Equilibrium Swelling Ratio (ESR), Water Vapor Transmission Test (WVTR), mechanical properties, scanning electron microscopy (SEM), MTT [3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide] assay, antibacterial studies, in vivo wound healing effect and histopathology of the hydrogel membranes were then performed. The examination revealed that the hydrogel membranes were more effective as a wound dressing in the early stages of wound healing and that the gel could be used in topic applications requiring a large spectrum of antibacterial activity; namely, as a bandage for wound dressing.
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BWR fuel experience with zinc injection
International Nuclear Information System (INIS)
Levin, H.A.; Garcia, S.E.
1995-01-01
In 1982 a correlation between low primary recirculation system dose rates in BWR's and the presence of ionic zinc in reactor water was identified. The source of the zinc was primarily from Admiralty brass condensers. Plants with brass condensers are called ''natural zinc'' plants. Brass condensers were also a source of copper that was implicated in crude induced localized corrosion (CILC) fuel failures. In 1986 the first BWR intentionally injected zinc for the benefits of dose rate control. Although zinc alone was never implicated in fuel degradation of failures, a comprehensive fuel surveillance program was initiated to monitor fuel performance. Currently there are 14 plants that are injecting zinc. Six of these plants are also on hydrogen water chemistry. This paper describes the effect on both Zircaloy corrosion and the cruding characteristics as a result of these changes in water chemistry. Fuel rod corrosion was found to be independent of the specific water chemistry of the plants. The corrosion behavior was the same with the additions of zinc alone or zinc plus hydrogen and well within the operating experience for fuel without either of these additions. No change was observed in the amounts of crude deposited on the fuel rods, both for the adherent and loosely held deposits. One of the effects of the zinc addition was the trend to form more of the zinc rich iron spinel in the fuel deposits rather than the hematite deposits that are predominantly formed with non additive water chemistry
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Brun, N.R.; Lenz, M.; Wehrli, B.; Fent, K.
2014-01-01
The increasing use of zinc oxide nanoparticles (nZnO) and their associated environmental occurrence make it necessary to assess their potential effects on aquatic organisms. Upon water contact, nZnO dissolve partially to zinc (Zn(II)). To date it is not yet completely understood, whether effects of
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Evaluation of the ignition behaviour of coals and blends
Energy Technology Data Exchange (ETDEWEB)
J. Faundez; F. Rubiera; X. Garcia; A. Arenillas; A.L. Gordon; J.J. Pis [CSIC, Instituto Nacional del Carbon, Oviedo (Spain). Department of Energy and Environment
2003-07-01
An experimental study about ignition of coals and blends was carried out by using an entrained flow reactor (EFR) with continuous feed. Seven coals of varying rank, from subbituminous to semianthracite, were tested and evolving gases (O{sub 2}, CO, CO{sub 2}, NO) were measured. The ignition temperature was evaluated from the evolution profiles of these gases, and correlated inversely to the reactivity of coals, as reflected by increasing values of ignition temperatures in the sequence subbituminous, high volatile bituminous, low volatile bituminous and semianthracite coals. Mechanism of ignition varied from an heterogeneous mechanism (for subbituminous, low volatile bituminous and semianthracite coals) to an homogeneous mechanism (for high volatile bituminous coal). Experiments with coal blends showed that if a low volatile bituminous coal is blended with a high volatile bituminous coal, the latter determines the value of the ignition temperature and ignition mechanism of the blend, when its percentage in the blend is 50% or higher. For blends of subbituminous and high volatile bituminous coals, the ignition mechanism of the blend is determined by the ignition mechanism of the coal with a higher content in the blend. 12 refs., 9 figs., 1 tab.
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International Nuclear Information System (INIS)
Mejborn, H.
1990-01-01
Endogenous zinc excretion was studied in adult male mink fed experimental diets for 73 d, including a collection period from d 69 to 73. Dietary zinc levels were 2.8, 26 or 121 mg/kg wet weight. In accordance with the results of a methodological study, also reported here, the animals had an intramuscular injection of 65ZnCl2 12 d before the start of the collection period. Total fecal (endogenous + unabsorbed) zinc excretion for d 69-73 in the three groups was 2.3, 20.4 and 91.0 mg. The endogenous zinc excretion was 1.3, 2.0 and 6.4 mg, corresponding to 80.8, 10.6 and 6.4% of the zinc intake. Thus, the endogenous excretion was mainly important for the zinc homeostasis at low zinc intake, whereas at high intake the homeostasis was regulated via absorption from the digestive tract. The overall conclusion of the experiment was that mink are comparable to other species (including man) in regard to mechanisms controlling zinc homeostasis
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Improved colorimetric determination of serum zinc.
Johnson, D J; Djuh, Y Y; Bruton, J; Williams, H L
1977-07-01
We show how zinc may easily be quantified in serum by first using an optimum concentration of guanidine hydrochloride to cause release of zinc from proteins, followed by complexation of released metals with cyanide. The cyanide complex of zinc is preferentially demasked with chloral hydrate, followed by a colorimetric reaction between zinc and 4-(2-pyridylazo)resorcinol. This is a sensitive water-soluble ligand; its complex with zinc has an absorption maximum at 497 nm. Values found by this technique compare favorably with those obtained by atomic absorption spectroscopy.
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Photovoltaic cells employing zinc phosphide
Barnett, Allen M.; Catalano, Anthony W.; Dalal, Vikram L.; Masi, James V.; Meakin, John D.; Hall, Robert B.
1984-01-01
A photovoltaic cell having a zinc phosphide absorber. The zinc phosphide can be a single or multiple crystal slice or a thin polycrystalline film. The cell can be a Schottky barrier, heterojunction or homojunction device. Methods for synthesizing and crystallizing zinc phosphide are disclosed as well as a method for forming thin films.
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Numerical Simulation of Sloshing Phenomena in Cubic Tank with Multiple Baffles
Directory of Open Access Journals (Sweden)
Mi-An Xue
2012-01-01
Full Text Available A two-phase fluid flow model solving Navier-Stokes equations was employed in this paper to investigate liquid sloshing phenomena in cubic tank with horizontal baffle, perforated vertical baffle, and their combinatorial configurations under the harmonic motion excitation. Laboratory experiment of liquid sloshing in cubic tank with perforated vertical baffle was carried out to validate the present numerical model. Fairly good agreements were obtained from the comparisons between the present numerical results and the present experimental data, available numerical data. Liquid sloshing in cubic tank with multiple baffles was investigated numerically in detail under different external excitation frequencies. Power spectrum of the time series of free surface elevation was presented with the aid of fast Fourier transform technique. The dynamic impact pressures acting on the normal and parallel sidewalls were discussed in detail.
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International Nuclear Information System (INIS)
HEIBASHY, M.I.; EL-NAHLA, A.M.; ASHOUR, I.; SALEH, SH.Y.A.
2008-01-01
Thirty adult albino rats (Rattus rattus) at 6 weeks of age were divided into three groups (ten for each). The first group was fed a standard laboratory diet for 8 weeks (control). The second group was made obese by giving them 32% sucrose solution in addition to the standard laboratory diet .The third group was received zinc supplementation (50 mg zinc acetate/ litre) with their sucrose solution. Body weight of all rats was measured weekly for 8 weeks. At 14 weeks of age, rats were killed and fasting blood samples were obtained. Serum glucose, insulin, cholesterol, triglyceride, leptin, tumour necrosis factor-α and zinc were measured.Results showed remarkable changes in body weights in sucrose fed rats only when compared to control and supplemented zinc rats group. Serum glucose, insulin, cholesterol and triglycerides were significantly increased in sucrose fed rats than both control and sucrose with zinc group. Serum leptin showed significant increase in sucrose fed rats than control and also showed higher significant value in sucrose fed rats supplemented with zinc comparing with sucrose fed rats and control ones. Tumour necrosis factor-? did not show any significant difference between all groups. Serum zinc concentration was decreased significantly in sucrose fed rats as compared to control. On the other hand, it was increased significantly in sucrose fed rats supplemented with zinc than other both groups. It could be concluded that zinc supplementation induced hyperleptinemia caused ameliorating effects in obese rats
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International Nuclear Information System (INIS)
Sadighi, A.; Moradi, A.; Roshan, Marjan M.; Ostadrahimi, A.
2009-01-01
Objective was to determine the effect of zinc supplementation on callus information, serum zinc and alkaline phosphatase activity in humans. This randomized, double-blind, placebo controlled clinical trial was conducted on 60 patients with traumatic bone fracture referred to Shohada Hospital of Tabriz, Iran from August to December 2007. Subjects were randomly divided into 2 groups: cases (n=30), receiving one capsule of zinc sulfate consists of 50 mg zinc each day and the controls (n=30), receiving placebo for 60 days. Individual and clinical information was determined by a questionnaire: nutritional intake by 3 days food records at the beginning and the end of trial. Serum zinc and alkaline phosphatase was measured by atomic absorption spectroscopy and by enzymatic method. Callus information during fracture healing was evaluated by radiography of the bone. There was no significant difference in physical activity, gender, age, type of fractures and nutrient intake, between the 2 groups. The administration of zinc caused a significant elevation of serum zinc and alkaline phosphatase activity. Assessment of bone x-rays showed a significant progress in callus formation in cases compared to the controls. This study shows that zinc supplementation can stimulate fracture healing, however, it needs further study. (author)
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Cubic interaction in extended theories of massless higher-spin fields
Energy Technology Data Exchange (ETDEWEB)
Fradkin, E S; Vasiliev, M A
1987-08-17
A cubic interaction of all massless higher-spin fields with s greater than or equal to 1 is constructed, based on the extended higher-spin superalgebras suggested previously by one of us (M.V.). This interaction incorporates gravitational and Yang-Mills interactions of massless higher-spin fields, which turn out to be consistent in the cubic order. An essential novel feature of the gravitational higher-spin interaction is its non-analyticity in the cosmological constant. An explicit form is found for deformed higher-spin gauge transformations leaving the action invariant.
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Electrodeposition of zinc--nickel alloys coatings
Energy Technology Data Exchange (ETDEWEB)
Dini, J W; Johnson, H R
1977-10-01
One possible substitute for cadmium in some applications is a zinc--nickel alloy deposit. Previous work by others showed that electrodeposited zinc--nickel coatings containing about 85 percent zinc and 15 percent nickel provided noticeably better corrosion resistance than pure zinc. Present work which supports this finding also shows that the corrosion resistance of the alloy deposit compares favorably with cadmium.
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Zinc and immunity: An essential interrelation.
Maares, Maria; Haase, Hajo
2016-12-01
The significance of the essential trace element zinc for immune function has been known for several decades. Zinc deficiency affects immune cells, resulting in altered host defense, increased risk of inflammation, and even death. The micronutrient zinc is important for maintenance and development of immune cells of both the innate and adaptive immune system. A disrupted zinc homeostasis affects these cells, leading to impaired formation, activation, and maturation of lymphocytes, disturbed intercellular communication via cytokines, and weakened innate host defense via phagocytosis and oxidative burst. This review outlines the connection between zinc and immunity by giving a survey on the major roles of zinc in immune cell function, and their potential consequences in vivo. Copyright © 2016 Elsevier Inc. All rights reserved.
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Design of Sustainable Blended Products using an Integrated Methodology
DEFF Research Database (Denmark)
Yunus, Nor Alafiza Binti; Gernaey, Krist; Woodley, John
2013-01-01
This paper presents a systematic methodology for designing blended products consisting of three stages; product design, process identification and experimental verification. The product design stage is considered in this paper. The objective of this stage is to screen and select suitable chemicals...... to be used as building blocks in the mixture design, and then to propose the blend formulations that fulfill the desired product attributes. The result is a set of blends that match the constraints, the compositions, values of the target properties and information about their miscibility. The methodology has...... been applied to design several blended products. A case study on design of blended lubricants is highlighted. The objective is to identify blended products that satisfy the product attributes with at least similar or better performance compared to conventional products....
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Foster, Meika; Herulah, Ursula Nirmala; Prasad, Ashlini; Petocz, Peter; Samman, Samir
2015-06-05
Pregnant women are vulnerable to a low zinc status due to the additional zinc demands associated with pregnancy and foetal development. The present systematic review explores the relationship between habitual vegetarian diets and dietary zinc intake/status during pregnancy. The association between vegetarian diets and functional pregnancy outcome also is considered. A literature search was conducted of MEDLINE; PubMed; Embase; the Cochrane Library; Web of Science; and Scopus electronic databases up to September 2014. Six English-language observational studies qualified for inclusion in the systematic review. A meta-analysis was conducted that compared the dietary zinc intake of pregnant vegetarian and non-vegetarian (NV) groups; the zinc intake of vegetarians was found to be lower than that of NV (-1.38 ± 0.35 mg/day; p vegetarian nor NV groups met the recommended dietary allowance (RDA) for zinc. In a qualitative synthesis; no differences were found between groups in serum/plasma zinc or in functional outcomes associated with pregnancy. In conclusion; pregnant vegetarian women have lower zinc intakes than NV control populations and both groups consume lower than recommended amounts. Further information is needed to determine whether physiologic adaptations in zinc metabolism are sufficient to meet maternal and foetal requirements during pregnancy on a low zinc diet.
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Cationic Phospholipids Forming Cubic Phases: Lipoplex Structure and Transfection Efficiency
Energy Technology Data Exchange (ETDEWEB)
Koynova, Rumiana; Wang, Li; MacDonald, Robert C. (NWU)
2008-10-29
The transfection activity and the phase behavior of two novel cationic O-alkyl-phosphatidylcholines, 1,2-dioleoyl-sn-glycero-3-hexylphosphocholine (C6-DOPC) and 1,2-dierucoyl-sn-glycero-3-ethylphosphocholine (di22:1-EPC), have been examined with the aim of more completely understanding the mechanism of lipid-mediated DNA delivery. Both lipids form cubic phases: C6-DOPC in the entire temperature range from -10 to 90 C, while di22:1-EPC exhibits an irreversible lamellar-cubic transition between 50 and 70 C on heating. The lipoplexes formed by C6-DOPC arrange into hexagonal phase, while the lipoplexes of di22:1-EPC are lamellar. Both lipids exhibit lower transfection activity than the lamellar-forming 1,2-dioleoyl-sn-glycero-3-ethylphosphocholine (EDOPC). Thus, for the studied cationic phospholipid-DNA systems, the lipoplex phase state is a factor that does not seem to correlate with transfection activity. The parameter that exhibits better correlation with the transfection activity within the present data set is the phase state of the lipid dispersion prior to the addition of DNA. Thus, the lamellar lipid dispersion (EDOPC) produces more efficient lipoplexes than the dispersion with coexisting lamellar and cubic aggregates (diC22:1-EPC), which is even more efficient than the purely cubic dispersions (C6-DOPC; diC22:1-EPC after heating). It could be inferred from these data and from previous research that cubic phase lipid aggregates are unlikely to be beneficial to transfection. The lack of correlation between the phase state of lipoplexes and their transfection activity observed within the present data set does not mean that lipid phase state is generally unimportant for lipofection: a viewpoint now emerging from our previous studies is that the critical factor in lipid-mediated transfection is the structural evolution of lipoplexes within the cell, upon interacting and mixing with cellular lipids.
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Cationic phospholipids forming cubic phases: lipoplex structure and transfection efficiency.
Koynova, Rumiana; Wang, Li; Macdonald, Robert C
2008-01-01
The transfection activity and the phase behavior of two novel cationic O-alkyl-phosphatidylcholines, 1,2-dioleoyl- sn-glycero-3-hexylphosphocholine (C6-DOPC) and 1,2-dierucoyl- sn-glycero-3-ethylphosphocholine (di22:1-EPC), have been examined with the aim of more completely understanding the mechanism of lipid-mediated DNA delivery. Both lipids form cubic phases: C6-DOPC in the entire temperature range from -10 to 90 degrees C, while di22:1-EPC exhibits an irreversible lamellar-cubic transition between 50 and 70 degrees C on heating. The lipoplexes formed by C6-DOPC arrange into hexagonal phase, while the lipoplexes of di22:1-EPC are lamellar. Both lipids exhibit lower transfection activity than the lamellar-forming 1,2-dioleoyl- sn-glycero-3-ethylphosphocholine (EDOPC). Thus, for the studied cationic phospholipid-DNA systems, the lipoplex phase state is a factor that does not seem to correlate with transfection activity. The parameter that exhibits better correlation with the transfection activity within the present data set is the phase state of the lipid dispersion prior to the addition of DNA. Thus, the lamellar lipid dispersion (EDOPC) produces more efficient lipoplexes than the dispersion with coexisting lamellar and cubic aggregates (diC22:1-EPC), which is even more efficient than the purely cubic dispersions (C6-DOPC; diC22:1-EPC after heating). It could be inferred from these data and from previous research that cubic phase lipid aggregates are unlikely to be beneficial to transfection. The lack of correlation between the phase state of lipoplexes and their transfection activity observed within the present data set does not mean that lipid phase state is generally unimportant for lipofection: a viewpoint now emerging from our previous studies is that the critical factor in lipid-mediated transfection is the structural evolution of lipoplexes within the cell, upon interacting and mixing with cellular lipids.
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Cubic AlGaN/GaN structures for device application
Energy Technology Data Exchange (ETDEWEB)
Schoermann, Joerg
2007-05-15
The aim of this work was the growth and the characterization of cubic GaN, cubic AlGaN/GaN heterostructures and cubic AlN/GaN superlattice structures. Reduction of the surface and interface roughness was the key issue to show the potential for the use of cubic nitrides in futur devices. All structures were grown by plasma assisted molecular beam epitaxy on free standing 3C-SiC (001) substrates. In situ reflection high energy electron diffraction was first investigated to determine the Ga coverage of c-GaN during growth. Using the intensity of the electron beam as a probe, optimum growth conditions were found when a 1 monolayer coverage is formed at the surface. GaN samples grown under these conditions reveal excellent structural properties. On top of the c-GaN buffer c-AlGaN/GaN single and multiple quantum wells were deposited. The well widths ranged from 2.5 to 7.5 nm. During growth of Al{sub 0.15}Ga{sub 0.85}N/GaN quantum wells clear reflection high energy electron diffraction oscillations were observed indicating a two dimensional growth mode. We observed strong room-temperature, ultraviolet photoluminescence at about 3.3 eV with a minimum linewidth of 90 meV. The peak energy of the emission versus well width is reproduced by a square-well Poisson- Schroedinger model calculation. We found that piezoelectric effects are absent in c-III nitrides with a (001) growth direction. Intersubband transition in the wavelength range from 1.6 {mu}m to 2.1 {mu}m was systematically investigated in AlN/GaN superlattices (SL), grown on 100 nm thick c-GaN buffer layers. The SLs consisted of 20 periods of GaN wells with a thickness between 1.5 nm and 2.1 nm and AlN barriers with a thickness of 1.35 nm. The first intersubband transitions were observed in metastable cubic III nitride structures in the range between 1.6 {mu}m and 2.1 {mu}m. (orig.)
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Crystal Structures of GaN Nanodots by Nitrogen Plasma Treatment on Ga Metal Droplets
Directory of Open Access Journals (Sweden)
Yang-Zhe Su
2018-06-01
Full Text Available Gallium nitride (GaN is one of important functional materials for optoelectronics and electronics. GaN exists both in equilibrium wurtzite and metastable zinc-blende structural phases. The zinc-blende GaN has superior electronic and optical properties over wurtzite one. In this report, GaN nanodots can be fabricated by Ga metal droplets in ultra-high vacuum and then nitridation by nitrogen plasma. The size, shape, density, and crystal structure of GaN nanodots can be characterized by transmission electron microscopy. The growth parameters, such as pre-nitridation treatment on Si surface, substrate temperature, and plasma nitridation time, affect the crystal structure of GaN nanodots. Higher thermal energy could provide the driving force for the phase transformation of GaN nanodots from zinc-blende to wurtzite structures. Metastable zinc-blende GaN nanodots can be synthesized by the surface modification of Si (111 by nitrogen plasma, i.e., the pre-nitridation treatment is done at a lower growth temperature. This is because the pre-nitridation process can provide a nitrogen-terminal surface for the following Ga droplet formation and a nitrogen-rich condition for the formation of GaN nanodots during droplet epitaxy. The pre-nitridation of Si substrates, the formation of a thin SiNx layer, could inhibit the phase transformation of GaN nanodots from zinc-blende to wurtzite phases. The pre-nitridation treatment also affects the dot size, density, and surface roughness of samples.
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International Nuclear Information System (INIS)
Shin, Sang Soo; Kim, Hyeong Wook; Lee, Daun; Kang, Heoung Keun; Kim, Jin Woong; Heo, Suk Hee; Jeong, Yong Yeon; Seon, Hyun Ju
2012-01-01
To compare the linear blending image with the nonlinear moidal blending image using dual energy CT for the evaluation of the viable portion of hepatocellular carcinoma (HCC) after transcatheter arterial chemoembolization (TACE). One-hundred and twenty three HCC patients incompletely treated after TACE were enrolled in this study. The dual energy mode (80 kVp and Sn140 kVp) was only applied in the late arterial phase scanning. A paired t-test was used to compare the lesion-to-liver contrast-to-noise ratio (CNR) and the image noise between the two blending images. Lesion conspicuity, image sharpness, image noise and the overall image quality between the two blending images were compared using the Wilcoxon matched-pair signed-ranks test. The lesion-to-liver CNR was significantly higher on the moidal blending image (5.6 ± 3.2) than on the linear blending image (2.7 ± 1.6) (p < 0.001). The image noise was significantly lower on the moidal blending image (10.9 ± 3.5) than on the linear blending image (17.5 ± 5.5) (p < 0.001). The lesion conspicuity and overall image quality were significantly better on the moidal blending image for both reviewers (p < 0.001). However, with respect to image sharpness, the linear blending image was significantly better for both reviewers (p < 0.01). The nonlinear moidal blending image of dual energy CT showed an increased lesion-to-liver CNR, decreased noise and improved overall image quality for the evaluation of the viable portion of HCC after TACE.
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Shah, Dheeraj; Sachdev, Harshpal S; Gera, Tarun; De-Regil, Luz Maria; Peña-Rosas, Juan Pablo
2016-06-09
Zinc deficiency is a global nutritional problem, particularly in children and women residing in settings where diets are cereal based and monotonous. It has several negative health consequences. Fortification of staple foods with zinc may be an effective strategy for preventing zinc deficiency and improving zinc-related health outcomes. To evaluate the beneficial and adverse effects of fortification of staple foods with zinc on health-related outcomes and biomarkers of zinc status in the general population. We searched the following databases in April 2015: Cochrane Central Register of Controlled Trials (CENTRAL, Issue 3 of 12, 2015, the Cochrane Library), MEDLINE & MEDLINE In Process (OVID) (1950 to 8 April 2015), EMBASE (OVID) (1974 to 8 April 2015), CINAHL (1982 to April 2015), Web of Science (1900 to 9 April 2015), BIOSIS (1969 to 9 April 2015), POPLINE (1970 to April 2015), AGRICOLA, OpenGrey, BiblioMap, and Trials Register of Promoting Health Interventions (TRoPHI), besides regional databases (April 2015) and theses. We also searched clinical trial registries (17 March 2015) and contacted relevant organisations (May 2014) in order to identify ongoing and unpublished studies. We included randomised controlled trials, randomised either at the level of the individual or cluster. We also included non-randomised trials at the level of the individual if there was a concurrent comparison group. We included non-randomised cluster trials and controlled before-after studies only if there were at least two intervention sites and two control sites. Interventions included fortification (central/industrial) of staple foods (cereal flours, edible fats, sugar, condiments, seasonings, milk and beverages) with zinc for a minimum period of two weeks. Participants were members of the general population who were over two years of age (including pregnant and lactating women) from any country. Two review authors independently assessed the eligibility of studies for inclusion
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Preparation of LDPE/LNR Blend Via Emulsion Dispersion
International Nuclear Information System (INIS)
Rusli Daik; Yee Lee Ching
2007-01-01
Low density polyethylene (LDPE)/ liquid natural rubber (LNR) blends with the composition of 100LDPE/ 0LNR, 70LDPE/ 30LNR, 60LDPE/ 40LNR and 40LDPE/ 60LNR were prepared via dispersion of LDPE and LNR emulsion. LNR was obtained via photochemical sensitization of natural rubber (NR). Emulsion of LNR was prepared by using sodium dodecyl sulfate (SDS) and 1-hexanol as the emulsifier and co- emulsifier respectively. Emulsion of LDPE was prepared in the same way by using LDPE solution in carbon tetrachloride, SDS and 1-hexanol. LDPE/ LNR blends were prepared via mixing of LNR and LDPE emulsions. Mechanical properties of the blends were analyzed by tensile, hardness and impact test. Optimum mechanical properties were observed for composite with composition of 60LDPE/ 40LNR that showed the maximum value of stress and strain. The glass transition temperature, T g , of the blends as obtained from differential scanning calorimetric (DSC) showed that the blends were homogeneous. Morphology study by using scanning electron microscopy (SEM) also indicates the homogeneity of LDPE/ LNR blends produced. (author)
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Preparation and Characterization of Keratin/Alginate Blend Microparticles
Directory of Open Access Journals (Sweden)
Yaowalak Srisuwan
2018-01-01
Full Text Available The water-in-oil (W/O emulsification-diffusion method was used for construction of keratin (Ker, alginate (Alg, and Ker/Alg blend microparticles. The Ker, Alg, and Ker/Alg blend solutions were used as the water phase, while ethyl acetate was used as the oil phase. Firstly, different concentrations of Ker solution was used to find suitable content. 1.6% w/v Ker solution was blended with the same concentration of the Alg solution for further microparticle construction. Results from scanning electron microscope analysis show that the microparticles have different shapes: spherical, bowl-like, porous, and hollow, with several sizes depending on the blend ratio. FTIR and TG analyses indicated that the secondary structure and thermal stability of the microparticles were influenced by the Ker/Alg blend ratio. The interaction between functional groups of keratin and alginate was the main factor for both β-sheet structure and Td,max values of the microparticles. The results suggested that Ker/Alg blend microparticles might be applied in many fields by varying the Ker/Alg ratio.
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Status of zinc injection in PWRs
Energy Technology Data Exchange (ETDEWEB)
Bergmann, C.A. [Westinghouse Electric Co., Pittsburgh, PA (United States)
1995-03-01
Based on laboratory and other studies, it was concluded that zinc addition in a PWR primary coolant should result in reduced Alloy 600 PWSCC and general corrosion rates of the materials of construction. Because of these positive results, a Westinghouse Owner`s Subgroup, EPRI, and Westinghouse provided funds to continue the development and application of zinc in an operating plant. As part of the program, Southern Operating Nuclear Company agreed to operate the Farley 2 plant with zinc addition as a demonstration test of the effectiveness of zinc. Since zinc is incorporated in the corrosion oxide film on the primary system surfaces and Farley 2 is a mature plant, it was estimated that about 10 kgs of zinc would be needed to condition the plant before an equilibrium value in the coolant would be reached. The engineered aspects of a Zinc Addition and Monitoring System (ZAMS) considered such items as the constitutents, location, sizing and water supply of the ZAMS. Baseline data such as the PWSCC history of the Alloy 600 steam generator tubing, fuel oxide thickness, fuel crud deposits, radiation levels, and RCP seal leak-off rates were obtained before zinc addition is initiated. This presentation summarizes some of the work performed under the program, and the status of zinc injection in the Farley 2 plant.
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International Nuclear Information System (INIS)
Floersheim, G.L.; Bieri, A.
1990-01-01
Protection of the haematocrit and thrombocytes by small doses of the aminothiol radioprotector WR 2721 was markedly improved by the concomitant administration of small doses of zinc aspartate. Zinc aspartate was the only one of the tested zinc salts not inhibiting the regression induced by radiotherapy of human tumours grown as xenografts in immunosuppressed mice. This also applied to zinc aspartate with WR 2721. A dose of zinc aspartate which afforded synergistic haematological protection did not enhance the toxicity of WR 2721. The synergism of zinc aspartate with WR 2721 and the differential radioprotection of the combined protocol may make it possible in clinical cancer radiotherapy to obtain selective radioprotection at a lower toxicity giving an improved therapeutic ratio compared with WR 2721 alone. (author)
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Dipeptide-based polyphosphazene and polyester blends for bone tissue engineering.
Deng, Meng; Nair, Lakshmi S; Nukavarapu, Syam P; Jiang, Tao; Kanner, William A; Li, Xudong; Kumbar, Sangamesh G; Weikel, Arlin L; Krogman, Nicholas R; Allcock, Harry R; Laurencin, Cato T
2010-06-01
Polyphosphazene-polyester blends are attractive materials for bone tissue engineering applications due to their controllable degradation pattern with non-toxic and neutral pH degradation products. In our ongoing quest for an ideal completely miscible polyphosphazene-polyester blend system, we report synthesis and characterization of a mixed-substituent biodegradable polyphosphazene poly[(glycine ethyl glycinato)(1)(phenyl phenoxy)(1)phosphazene] (PNGEG/PhPh) and its blends with a polyester. Two dipeptide-based blends namely 25:75 (Matrix1) and 50:50 (Matrix2) were produced at two different weight ratios of PNGEG/PhPh to poly(lactic acid-glycolic acid) (PLAGA). Blend miscibility was confirmed by differential scanning calorimetry, Fourier transform infrared spectroscopy, and scanning electron microscopy. Both blends resulted in higher tensile modulus and strength than the polyester. The blends showed a degradation rate in the order of Matrix2PLAGA in phosphate buffered saline at 37 degrees C over 12 weeks. Significantly higher pH values of degradation media were observed for blends compared to PLAGA confirming the neutralization of PLAGA acidic degradation by polyphosphazene hydrolysis products. The blend components PLAGA and polyphosphazene exhibited a similar degradation pattern as characterized by the molecular weight loss. Furthermore, blends demonstrated significantly higher osteoblast growth rates compared to PLAGA while maintaining osteoblast phenotype over a 21-day culture. Both blends demonstrated improved biocompatibility in a rat subcutaneous implantation model compared to PLAGA over 12 weeks. (c) 2010 Elsevier Ltd. All rights reserved.
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Serum zinc levels in gestational diabetes
Directory of Open Access Journals (Sweden)
Rahimi Sharbaf F
2008-12-01
Full Text Available "nBackground: Maternal zinc deficiency during pregnancy has been related to adverse pregnancy outcomes. Most studies in which pregnant women have been supplemented with zinc to examine its effects on the outcome of the pregnancy have been carried out in industrialized countries and the results have been inconclusive. It has been shown that women with gestational diabetes (GDM have lower serum zinc levels than healthy pregnant women, and higher rates of macrosomia. Zinc is required for normal glucose metabolism, and strengthens the insulin-induced transportation of glucose into cells by its effect on the insulin signaling pathway. The purpose of this study was to assess the serum zinc levels of GDM patients and evaluate the effect of zinc supplementation. "nMethods: In the first stage of this prospective controlled study, we enrolled 70 women who were 24-28 weeks pregnant at the Prenatal Care Center of Mirza Kochak Khan Hospital, Tehran, Iran. The serum zinc level of each subject was determined. In the second stage, among these 70 subjects, the diabetics receiving insulin were divided into two groups, only one of which received a zinc supplement and the other group was the control group. Birth weight of neonates and insulin dosages were recorded. "nResults: The mean serum zinc level in the GDM group was lower than that of the control group (94.83 vs. 103.49mg/dl, respectively and the mean birth weight of neonates from the GDM women who received the zinc supplement was lower than that of the control group (3849g vs. 4136g. The rate of macrosomia was lower in the zinc supplemented group (20% vs. 53%. The mean of increase of insulin after receiving the zinc supplement was lower (8.4u vs. 13.53. "nConclusion: Maternal insulin resistance is associated with the accumulation of maternal fat tissue during early stages of pregnancy and greater fetoplacental nutrient availability in later stages, when 70% of fetal growth occurs, resulting in macrosomia. In
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Blended Learning Opportunities in Ukrainian IT Public Education
Szimkovics, Tamás
2017-01-01
Based on previous surveys the usage of ICT and blended learning is at a low level in Ukraine. To catch up with the European average, it is important to familiarize the students and teachers with blended learning in the secondary school. The information technology classes provide the best opportunity to introduce the blended learning, because they…
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Multiscattering illumination in blended acquisition design
Berkhout, A.J.; Blacquière, G.; Verschuur, D.J.
2010-01-01
In traditional seismic surveys the firing time between shots is such that the records do not interfere in time. However, in the concept of blending the records do overlap, allowing much denser and wider geometries in an economic way. The blending parameters are the locations of the involved sources
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Bliuc, Ana-Maria; Casey, Grant; Bachfischer, Agnieszka; Goodyear, Peter; Ellis, Robert A.
2012-01-01
This paper presents research exploring teachers' experiences of using blended learning in vocational education. Teachers involved in designing and teaching using blended learning from a major Australian vocational education provider participated in the study. They received open-ended questionnaires asking to describe their conceptions of blended…
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Blended Learning in Action: A Practical Guide toward Sustainable Change
Tucker, Catlin R.; Wycoff, Tiffany; Green, Jason T.
2017-01-01
Blended learning has the power to reinvent education, but transitioning to a blended model is challenging. Blended learning requires a fundamentally new approach to learning as well as a new skillset for both teachers and school leaders. Loaded with research, examples, and resources, "Blended Learning in Action" demonstrates the…
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Zinc phosphate conversion coatings
Sugama, Toshifumi
1997-01-01
Zinc phosphate conversion coatings for producing metals which exhibit enhanced corrosion prevention characteristics are prepared by the addition of a transition-metal-compound promoter comprising a manganese, iron, cobalt, nickel, or copper compound and an electrolyte such as polyacrylic acid, polymethacrylic acid, polyitaconic acid and poly-L-glutamic acid to a phosphating solution. These coatings are further improved by the incorporation of Fe ions. Thermal treatment of zinc phosphate coatings to generate .alpha.-phase anhydrous zinc phosphate improves the corrosion prevention qualities of the resulting coated metal.
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A drop penetration method to measure powder blend wettability.
Wang, Yifan; Liu, Zhanjie; Muzzio, Fernando; Drazer, German; Callegari, Gerardo
2018-03-01
Water wettability of pharmaceutical blends affects important quality attributes of final products. We investigate the wetting properties of a pharmaceutical blend lubricated with Magnesium Stearate (MgSt) as a function of the mechanical shear strain applied to the blend. We measure the penetration dynamics of sessile drops deposited on slightly compressed powder beds. We consider a blend composed of 9% Acetaminophen 90% Lactose and 1% MgSt by weight. Comparing the penetration time of water and a reference liquid Polydimethylsiloxane (silicon oil) we obtain an effective cosine of the contact angle with water, based on a recently developed drop penetration method. We repeat the experiments for blends exposed to increasing levels of shear strain and demonstrate a significant decrease in water wettability (decrease in the cosine of the contact angle). The results are consistent with the development of a hydrophobic film coating the powder particles as a result of the increased shear strain. Finally, we show that, as expected dissolution times increase with the level of shear strain. Therefore, the proposed drop penetration method could be used to directly assess the state of lubrication of a pharmaceutical blend and act as a quality control on powder blend attributes before the blend is tableted. Copyright © 2017 Elsevier B.V. All rights reserved.
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On the number of longest and almost longest cycles in cubic graphs
DEFF Research Database (Denmark)
Chia, Gek Ling; Thomassen, Carsten
2012-01-01
We consider the questions: How many longest cycles must a cubic graph have, and how many may it have? For each k >= 2 there are infinitely many p such that there is a cubic graph with p vertices and precisely one longest cycle of length p-k. On the other hand, if G is a graph with p vertices, all...
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CubiCal - Fast radio interferometric calibration suite exploiting complex optimisation
Kenyon, J. S.; Smirnov, O. M.; Grobler, T. L.; Perkins, S. J.
2018-05-01
It has recently been shown that radio interferometric gain calibration can be expressed succinctly in the language of complex optimisation. In addition to providing an elegant framework for further development, it exposes properties of the calibration problem which can be exploited to accelerate traditional non-linear least squares solvers such as Gauss-Newton and Levenberg-Marquardt. We extend existing derivations to chains of Jones terms: products of several gains which model different aberrant effects. In doing so, we find that the useful properties found in the single term case still hold. We also develop several specialised solvers which deal with complex gains parameterised by real values. The newly developed solvers have been implemented in a Python package called CubiCal, which uses a combination of Cython, multiprocessing and shared memory to leverage the power of modern hardware. We apply CubiCal to both simulated and real data, and perform both direction-independent and direction-dependent self-calibration. Finally, we present the results of some rudimentary profiling to show that CubiCal is competitive with respect to existing calibration tools such as MeqTrees.
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Non-isothermal crystallization of PET/PLA blends
International Nuclear Information System (INIS)
Chen, Huipeng; Pyda, Marek; Cebe, Peggy
2009-01-01
Binary blends of poly(ethylene terephthalate) with poly(lactic acid), PET/PLA, were studied by differential scanning calorimetry and X-ray scattering. The PET/PLA blends, prepared by solution casting, were found to be miscible in the melt over the entire composition range. Both quenched amorphous and semicrystalline blends exhibit a single, composition dependent glass transition temperature. We report the non-isothermal crystallization of (a) PET, with and without the presence of PLA crystals and (b) PLA, with and without the presence of PET crystals. PET can crystallize in all blends, regardless of whether PLA is amorphous or crystalline, and degree of crystallinity of PET decreases as PLA content increases. In contrast, PLA crystallization is strongly affected by the mobility of the PET fraction. When PET is wholly amorphous, PLA can crystallize even in 70/30 blends, albeit weakly. But when PET is crystalline, PLA cannot crystallize when its own content drops below 0.90. These different behaviors may possibly be related to the tendency of each polymer to form constrained chains, i.e., to form the rigid amorphous fraction, or RAF. PET is capable of forming a large amount of RAF, whereas relatively smaller amount of RAF forms in PLA. Like the crystals, the rigid amorphous fraction of one polymer component may inhibit the growth of crystals of the other blend partner.
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Chitosan-Based Polymer Blends: Current Status and applications
International Nuclear Information System (INIS)
Hefian, E.A.E.; Nasef, M.M.
2014-01-01
This paper reviews the latest developments in chitosan-based blends and their potential applications in various fields. Various blends together with other derivatives, such as composites and graft copolymers, have been developed to overcome chitosans disadvantages, including poor mechanical properties and to improve its functionality towards specific applications. The progress made in blending chitosan with synthetic and natural polymers is presented. The versatility and unique characteristics, such as hydrophilicity, film-forming ability, biodegradability, biocompatibility, antibacterial activity and non-toxicity of chitosan has contributed to the successful development of various blends for medical, pharmaceutical, agricultural and environmental applications. (author)
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Highly Aminated Mesoporous Silica Nanoparticles with Cubic Pore Structure
Suteewong, Teeraporn; Sai, Hiroaki; Cohen, Roy; Wang, Suntao; Bradbury, Michelle; Baird, Barbara; Gruner, Sol M.; Wiesner, Ulrich
2011-01-01
Mesoporous silica with cubic symmetry has attracted interest from researchers for some time. Here, we present the room temperature synthesis of mesoporous silica nanoparticles possessing cubic Pm3n symmetry with very high molar ratios (>50%) of 3-aminopropyl triethoxysilane. The synthesis is robust allowing, for example, co-condensation of organic dyes without loss of structure. By means of pore expander molecules, the pore size can be enlarged from 2.7 to 5 nm, while particle size decreases. Adding pore expander and co-condensing fluorescent dyes in the same synthesis reduces average particle size further down to 100 nm. After PEGylation, such fluorescent aminated mesoporous silica nanoparticles are spontaneously taken up by cells as demonstrated by fluorescence microscopy.
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Highly Aminated Mesoporous Silica Nanoparticles with Cubic Pore Structure
Suteewong, Teeraporn
2011-01-19
Mesoporous silica with cubic symmetry has attracted interest from researchers for some time. Here, we present the room temperature synthesis of mesoporous silica nanoparticles possessing cubic Pm3n symmetry with very high molar ratios (>50%) of 3-aminopropyl triethoxysilane. The synthesis is robust allowing, for example, co-condensation of organic dyes without loss of structure. By means of pore expander molecules, the pore size can be enlarged from 2.7 to 5 nm, while particle size decreases. Adding pore expander and co-condensing fluorescent dyes in the same synthesis reduces average particle size further down to 100 nm. After PEGylation, such fluorescent aminated mesoporous silica nanoparticles are spontaneously taken up by cells as demonstrated by fluorescence microscopy.
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TANK 21 AND TANK 24 BLEND AND FEED STUDY: BLENDING TIMES, SETTLING TIMES, AND TRANSFERS
Energy Technology Data Exchange (ETDEWEB)
Lee, S.; Leishear, R.; Poirier, M.
2012-05-31
The Salt Disposition Integration (SDI) portfolio of projects provides the infrastructure within existing Liquid Waste facilities to support the startup and long term operation of the Salt Waste Processing Facility (SWPF). Within SDI, the Blend and Feed Project will equip existing waste tanks in the Tank Farms to serve as Blend Tanks where salt solutions of up to 1.2 million gallons will be blended in 1.3 million gallon tanks and qualified for use as feedstock for SWPF. In particular, Tanks 21 and 24 are planned to be used for blending and transferring to the SDI feed tank. These tanks were evaluated here to determine blending times, to determine a range of settling times for disturbed sludge, and to determine that the SWPF Waste Acceptance Criteria that less than 1200 mg/liter of solids will be entrained in salt solutions during transfers from the Tank 21 and Tank 24 will be met. Overall conclusions for Tank 21 and Tank 24 operations include: (1) Experimental correction factors were applied to CFD (computational fluid dynamics) models to establish blending times between approximately two and five hours. As shown in Phase 2 research, blending times may be as much as ten times greater, or more, if lighter fluids are added to heavier fluids (i.e., water added to salt solution). As the densities of two salt solutions converge this effect may be minimized, but additional confirmatory research was not performed. (2) At the current sludge levels and the presently planned operating heights of the transfer pumps, solids entrainment will be less than 1200 mg/liter, assuming a conservative, slow settling sludge simulant. (3) Based on theoretical calculations, particles in the density range of 2.5 to 5.0 g/mL must be greater than 2-4 {micro}m in diameter to ensure they settle adequately in 30-60 days to meet the SWPF feed criterion (<1200 mg/l). (4) Experimental tests with sludge batch 6 simulant and field turbidity data from a recent Tank 21 mixing evolution suggest the solid
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Shape memory behaviour of radiation-crosslinked PCL/PMVS blends
International Nuclear Information System (INIS)
Zhu Guangming; Xu Shuogui; Wang Jinhua; Zhang Longbin
2006-01-01
The performance and radiation crosslinking of polycaprolactone (PCL) and polymethylvinylsiloxane (PMVS) blends has been investigated. Radiation crosslinking of PCL/PMVS blends followed the Charlesby-Pinner equation, and PMVS promoted the radiation crosslinking of the blends. As the concentration of PMVS increased, the gelation dose and the ratio of degradation to crosslinking (p 0 /q 0 ) decreased and the efficiency of radiation crosslinking increased. The elastic modulus below the melting point of PCL of radiation-crosslinked PCL/PMVS blends decreased with the increase of PMVS, and increased above the melting point. The crosslinked PCL/PMVS blends exhibited excellent shape memory effects, and the ratios of deformation to recovery were more than 95%
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First Principles Investigation of Zinc-anode Dissolution in Zinc-air Batteries
DEFF Research Database (Denmark)
Siahrostami, Samira; Tripkovic, Vladimir; Lundgård, Keld Troen
2013-01-01
With surging interest in high energy density batteries, much attention has recently been devoted to metal-air batteries. The zinc-air battery has been known for more than hundred years and is commercially available as a primary battery, but recharging has remained elusive; in part because...... the fundamental mechanisms still remain to be fully understood. Here, we present a density functional theory investigation of the zinc dissolution (oxidation) on the anode side in the zinc-air battery. Two models are envisaged, the most stable (0001) surface and a kink surface. The kink model proves to be more....... The applied methodology provides new insight into computational modelling and design of secondary metal-air batteries....
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The effect of severe zinc deficiency and zinc supplement on spatial learning and memory.
Tahmasebi Boroujeni, S; Naghdi, N; Shahbazi, M; Farrokhi, A; Bagherzadeh, F; Kazemnejad, A; Javadian, M
2009-07-01
Zinc deficiency during pregnancy and during lactation has been shown to impair cognitive function and motor activity in offspring rats. In the present study, the effect of zinc deficiency and zinc supplement on spatial learning and memory in Morris Water Maze (MWM) and motor activity in open field were investigated. Pregnant rats after mating were divided to three groups. Control group fed a standard diet and a zinc deficient (ZnD) group fed a diet deficient in zinc (0.5-1.5 ppm) and a zinc supplement (ZnS) group fed a standard diet and enhanced zinc in the drinking water (10 ppm). All the diets were exposed during the last trisemester of pregnancy and during lactation. Rat's offspring in these groups were tested for spatial learning and memory in MWM at post natal day (PND) 56 and were tested for motor activity in open field at PND 66.The Escape Latency (EL) and Traveled Distance (TD) in the ZnD group were increased but Percentage of Time Spent in the target quadrant (PTS) was decreased compared to the control group. In addition, these were no significant differences in EL and TD, but PTS had significant increase in ZnS compared to the control group. In the open field, Total Distance Moved (TDM) and Time of Motor Activity (TMA) for the ZnD were decreased compared to the control group, but there were no significant differences in TDM and TMA between control and ZnS groups. These findings suggest that zinc deficiency during the last trimester of pregnancy and during lactation impaired spatial learning and memory in their offsprings and has also negative effect on motor activity. In addition, ZnS has a significant effect on spatial learning and memory but no effect on motor activity in their offsprings.
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Method to blend separator powders
Guidotti, Ronald A.; Andazola, Arthur H.; Reinhardt, Frederick W.
2007-12-04
A method for making a blended powder mixture, whereby two or more powders are mixed in a container with a liquid selected from nitrogen or short-chain alcohols, where at least one of the powders has an angle of repose greater than approximately 50 degrees. The method is useful in preparing blended powders of Li halides and MgO for use in the preparation of thermal battery separators.
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Directory of Open Access Journals (Sweden)
El-Shazly AN
2015-12-01
Full Text Available Ahmed Nabih El-Shazly,1 Soha Abd El-Hady Ibrahim,1 Ghada Mohamed El-Mashad,2 Jehan H Sabry,3 Nashwa Said Sherbini11Department of Pediatrics, Faculty of Medicine, Benha University, Banha, 2Department of Pediatrics, Faculty of Medicine, Menoufia University, Shibin Al Kawm, 3Department of Clinical and Chemical Pathology, Faculty of Medicine, Benha University, Banha, Egypt Introduction: Zinc is an essential trace element for human nutrition, and its deficiency is associated with anorexia, poor food efficiency, growth retardation, and impaired neurological and immune systems. The zinc-deficiency rate is particularly high in many disease states, such as with end-stage renal disease patients undertaking hemodialysis. The aim of this study was to determine the effect of zinc supplementation on body mass index (BMI and serum levels of zinc and leptin in pediatric hemodialysis patients. Patients and methods: This was a prospective clinical trial study in which 60 hemodialysis patients were randomly divided into two groups: group I received 50–100 mg zinc sulfate (equivalent to 11–22 mg elemental zinc according to age, sex, and nutritional status of the child; and group II received placebo (cornstarch twice daily for 90 days. Anthropometric measurements were taken, and serum zinc and leptin levels were determined by colorimetric test with 5-Br-3'-phosphoadenosine-5'-phosphosulfate and enzyme-linked immunosorbent assay, respectively, at days 0 and 90 of the study. Results: Zinc supplementation resulted in a significant increase in mean serum zinc level and BMI. Serum leptin decreased significantly after supplementation in children under hemodialysis. A significant negative correlation was observed between serum zinc and leptin levels as a result of zinc supplementation. Conclusion: There was an increase in serum zinc level and BMI and decreased serum leptin after zinc supplementation in children under hemodialysis. Keywords: serum zinc, serum leptin
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International Nuclear Information System (INIS)
Liu Pulin; Huang Qiaoyun; Chen Wenli
2012-01-01
The inducibility and specificity of different czcRS operons in Pseudomonas putida X4 were studied by lacZ gene fusions. The data of β-glycosidase activity confirmed that the czcR3 promoter responded quantitatively to zinc. A zinc-specific biosensor, P. putida X4 (pczcR3GFP), was constructed by fusing a promoterless enhanced green fluorescent protein (egfp) gene with the czcR3 promoter in the chromosome of P. putida X4. In water extracts of four different soils amended with zinc, the reporter strain detected about 90% of the zinc content of the samples. Both the bioavailability assessment and the sequential extraction analysis demonstrated that the immobilization of zinc was highly dependent on the physico-chemical properties of soils. The results also showed that the lability of zinc decreased over time. It is concluded that the biosensor constitutes an alternative system for the convenient evaluation of zinc toxicity in the environment. - Highlights: ► A zinc-specific bacterial biosensor was developed. ► Four spiked soils were used to test the application of this biosensor. ► The bioavailable zinc in soil-water extracts decreased due to aging. ► The immobilization and speciation of zinc were highly dependent on the soil type. - The immobilization and bioavailability of zinc in soil were investigated as a function of soil type and aging by a newly constructed zinc-specific biosensor coupled with chemical analysis.
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Study of PP/Polybutene Blends Modified by Gamma Irradiation and HMS-PP/Polybutene Blends
International Nuclear Information System (INIS)
Lugao, A. B.
2006-01-01
The polypropylene (PP) has been applied to a wide range of production due to its various excellent properties such as cheapness, high stiffness, chemical resistance, no environmental pollution when incinerated, low specific density and good mechanical properties. However, PP is a linear polymer which exhibits low melt strength. One of the effective approaches to achieve high melt strength (HMS) is to add chain branches onto backbone polymers. High melt strength polypropylene (HMS-PP) has been recently developed and introduced in the market by the major international polypropylene producers. As a consequence different methods have been applied to modify polypropylenes by chain branches. The technology obtained by IPEN together with EMBRARAD and BRASKEM comprises chain branches added onto backbone species using gamma radiation, which is generated from a Co 6 0 source. Such radiation is very convenient in order to improve polymer materials by grafting, crosslinking and degradation. Another important approach to the development of polymer materials is based on the combination of different polymers into a new product having some of the desired properties of each component. In this work, gamma irradiation technique was used to induce chemical changes in commercial polypropylene (HMS-PP) that was after blended with polybutene and in polypropylene/polybutene blends. The samples were irradiated with a 60 C o source at doses of 12,5 and 20kGy in the presence of acetylene. It was investigated how the two different routes of blends processing can modify their properties. Indeed the results from melt flow, gel fraction and rheology reveal the influence of the process route in the blends properties. Effects on the elongation at break and break strength were observed by the results of mechanical tests. The results from rheology demonstrated an increase in melt strength and drawability of the blends
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Blended learning in health education: three case studies.
de Jong, Nynke; Savin-Baden, Maggi; Cunningham, Anne Marie; Verstegen, Daniëlle M L
2014-09-01
Blended learning in which online education is combined with face-to-face education is especially useful for (future) health care professionals who need to keep up-to-date. Blended learning can make learning more efficient, for instance by removing barriers of time and distance. In the past distance-based learning activities have often been associated with traditional delivery-based methods, individual learning and limited contact. The central question in this paper is: can blended learning be active and collaborative? Three cases of blended, active and collaborative learning are presented. In case 1 a virtual classroom is used to realize online problem-based learning (PBL). In case 2 PBL cases are presented in Second Life, a 3D immersive virtual world. In case 3 discussion forums, blogs and wikis were used. In all cases face-to-face meetings were also organized. Evaluation results of the three cases clearly show that active, collaborative learning at a distance is possible. Blended learning enables the use of novel instructional methods and student-centred education. The three cases employ different educational methods, thus illustrating diverse possibilities and a variety of learning activities in blended learning. Interaction and communication rules, the role of the teacher, careful selection of collaboration tools and technical preparation should be considered when designing and implementing blended learning.
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Quantification of rice bran oil in oil blends
Energy Technology Data Exchange (ETDEWEB)
Mishra, R.; Sharma, H. K.; Sengar, G.
2012-11-01
Blends consisting of physically refined rice bran oil (PRBO): sunflower oil (SnF) and PRBO: safflower oil (SAF) in different proportions were analyzed for various physicochemical parameters. The quantification of pure rice bran oil in the blended oils was carried out using different methods including gas chromatographic, HPLC, ultrasonic velocity and methods based on physico-chemical parameters. The physicochemical parameters such as ultrasonic velocity, relative association and acoustic impedance at 2 MHz, iodine value, palmitic acid content and oryzanol content reflected significant changes with increased proportions of PRBO in the blended oils. These parameters were selected as dependent parameters and % PRBO proportion was selected as independent parameters. The study revealed that regression equations based on the oryzanol content, palmitic acid composition, ultrasonic velocity, relative association, acoustic impedance, and iodine value can be used for the quantification of rice bran oil in blended oils. The rice bran oil can easily be quantified in the blended oils based on the oryzanol content by HPLC even at a 1% level. The palmitic acid content in blended oils can also be used as an indicator to quantify rice bran oil at or above the 20% level in blended oils whereas the method based on ultrasonic velocity, acoustic impedance and relative association showed initial promise in the quantification of rice bran oil. (Author) 23 refs.
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Structuring of Interface-Modified Polymer Blends
DEFF Research Database (Denmark)
Lyngaae-Jørgensen, Jørgen
1999-01-01
The paper treats the case where blends of polystyrene (PS), poly (dimethylsiloxane) (PDMS) and a diblock copolymer of PS and PDMS are used as model materials. This modelsystem is predicted to be "stable" in discrete blends in simple shear flow. Stable in the sence that the block copolymer can not...
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Inhibitory zinc-enriched terminals in mouse spinal cord
DEFF Research Database (Denmark)
Danscher, G; Jo, S M; Varea, E
2001-01-01
The ultrastructural localization of zinc transporter-3, glutamate decarboxylase and zinc ions in zinc-enriched terminals in the mouse spinal cord was studied by zinc transporter-3 and glutamate decarboxylase immunohistochemistry and zinc selenium autometallography, respectively.The distribution...
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The Exact Limit of Some Cubic Towers
DEFF Research Database (Denmark)
Anbar Meidl, Nurdagül; Beelen, Peter; Nguyen, Nhut
2017-01-01
Recently, a new explicit tower of function fields was introduced by Bassa, Beelen, Garcia and Stichtenoth (BBGS). This resulted in currently the best known lower bound for Ihara’s constant in the case of non-prime finite fields. In particular over cubic fields, the tower’s limit is at least as go...
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X-ray diffraction from single GaAs nanowires
Energy Technology Data Exchange (ETDEWEB)
Biermanns, Andreas
2012-11-12
In recent years, developments in X-ray focussing optics have allowed to produce highly intense, coherent X-ray beams with spot sizes in the range of 100 nm and below. Together with the development of new experimental stations, X-ray diffraction techniques can now be applied to study single nanometer-sized objects. In the present work, X-ray diffraction is applied to study different aspects of the epitaxial growth of GaAs nanowires. Besides conventional diffraction methods, which employ X-ray beams with dimensions of several tens of {mu}m, special emphasis lies on the use of nanodiffraction methods which allow to study single nanowires in their as-grown state without further preparation. In particular, coherent X-ray diffraction is applied to measure simultaneously the 3-dimensional shape and lattice parameters of GaAs nanowires grown by metal-organic vapor phase epitaxy. It is observed that due to a high density of zinc-blende rotational twins within the nanowires, their lattice parameter deviates systematically from the bulk zinc-blende phase. In a second step, the initial stage in the growth of GaAs nanowires on Si (1 1 1) surfaces is studied. This nanowires, obtained by Ga-assisted growth in molecular beam epitaxy, grow predominantly in the cubic zinc-blende structure, but contain inclusions of the hexagonal wurtzite phase close to their bottom interface. Using nanodiffraction methods, the position of the different structural units along the growth axis is determined. Because the GaAs lattice is 4% larger than silicon, these nanowires release their lattice mismatch by the inclusion of dislocations at the interface. Whereas NWs with diameters below 50 nm are free of strain, a rough interface structure in nanowires with diameters above 100 nm prevents a complete plastic relaxation, leading to a residual strain at the interface that decays elastically along the growth direction. Finally, measurements on GaAs-core/InAs-shell nanowire heterostructures are presented
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Factors influencing zinc status of apparently healthy indians.
Agte, Vaishali V; Chiplonkar, Shashi A; Tarwadi, Kirtan V
2005-10-01
To identify dietary, environmental and socio-economic factors associated with mild zinc deficiency, three zinc status indices; erythrocyte membrane zinc (RBCMZn), plasma zinc and super oxide dismutase (SOD) were assessed in free living and apparently healthy Indian population. Dietary patterns of 232 men and 223 women (20-65 yr) from rural, industrial and urban regions of Western India were evaluated by food frequency questionnaire. RBCMZn was estimated using atomic absorption spectrometry, hemoglobin and serum ceruloplasmin by spectrophotometer. On a sub sample (48 men and 51 women) plasma zinc and SOD were also assessed. Mean RBCMZn was 0.5 +/- 0.1 micromols/g protein with 46% individuals showing zinc deficiency. Mean plasma zinc was 0.98 +/- 0.12 microg/mL with 25% men and 2.5% women having values below normal range. Mean SOD was 0.97 +/- 0.1 (u/mL cells). A significant positive correlation was observed between intakes of green leafy vegetables, other vegetables and milk products with RBCMZn status (p plasma zinc (p > 0.2). Cereal and legume intakes were negatively correlated with RBCMZn (p plasma zinc (p 0.2). Fruit and other vegetable intake were positively correlated with SOD (p Plasma zinc indicated positive association with zinc, thiamin and riboflavin intakes (p plasma zinc and SOD. Prominent determinants of zinc status were intakes of beta-carotene and zinc along with environmental conditions and family size.
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Modification of polymer blends by irradiation
International Nuclear Information System (INIS)
Zuchowska, D.; Zagorski, Z.P.
1999-01-01
Modification of polymers, especially of polyolefin-elastomer blends (e. g. ethylene/propylene/diene terpolymer, ethylene propylene copolymer, ethylene/vinyl acetate copolymer etc.), by irradiation with a beam of fast electrons is discussed. Irradiation of polymer blends usually results in enhanced interactions between the constituents, caused among other things, by grafting induced at the polymer interphase. As a result, mechanical properties are affected to an extent depending on the proportion and type of constituent polymers, stabilizer content and radiation dose. Breaking strength (σ) relative elongation at break (ε) and melt flow rate (MFR), were examined for a triblock styrene/butadiene/styrene (SBS) copolymer, polypropylene (PP), and a PP-SBS blend (50:50 by wt.). In PP, the content of the crystal phase was determined. Irradiation was found to make SBS crosslink, as a result, σ rose by 25% and ε remained unaffected. PP was found to become degraded upon irradiation (MFR rose as much as 16 times), thereby σ and ε decreased considerably. In pure PP, the content of the crystal phase was found to increase. The variations of σ and ε in the irradiated PP-SBS blend follow a tendency similar to that in the SBS copolymer examined. This fact suggests the SBS copolymer to have a decisive effect on the macroscopic properties of the PP-SBS blend. (author)
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Zinc absorption in inflammatory bowel disease
International Nuclear Information System (INIS)
Valberg, L.S.; Flanagan, P.R.; Kertesz, A.; Bondy, D.C.
1986-01-01
Zinc absorption was measured in 29 patients with inflammatory bowel disease and a wide spectrum of disease activity to determine its relationship to disease activity, general nutritional state, and zinc status. Patients with severe disease requiring either supplementary oral or parenteral nutrition were excluded. The mean 65ZnCl2 absorption, in the patients, determined using a 65Zn and 51Cr stool-counting test, 45 +/- 17% (SD), was significantly lower than the values, 54 +/- 16%, in 30 healthy controls, P less than 0.05. Low 65ZnCl2 absorption was related to undernutrition, but not to disease activity in the absence of undernutrition or to zinc status estimated by leukocyte zinc measurements. Mean plasma zinc or leukocyte zinc concentrations in patients did not differ significantly from controls, and only two patients with moderate disease had leukocyte zinc values below the 5th percentile of normal. In another group of nine patients with inflammatory bowel disease of mild-to-moderate severity and minimal nutritional impairment, 65Zn absorption from an extrinsically labeled turkey test meal was 31 +/- 10% compared to 33 +/- 7% in 17 healthy controls, P greater than 0.1. Thus, impairment in 65ZnCl2 absorption in the patients selected for this study was only evident in undernourished persons with moderate or severe disease activity, but biochemical evidence of zinc deficiency was uncommon, and clinical features of zinc depletion were not encountered
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Higher-Order Approximation of Cubic-Quintic Duffing Model
DEFF Research Database (Denmark)
Ganji, S. S.; Barari, Amin; Babazadeh, H.
2011-01-01
We apply an Artificial Parameter Lindstedt-Poincaré Method (APL-PM) to find improved approximate solutions for strongly nonlinear Duffing oscillations with cubic-quintic nonlinear restoring force. This approach yields simple linear algebraic equations instead of nonlinear algebraic equations...
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The zinc-myoglobin relationships in porcine muscles
International Nuclear Information System (INIS)
Fogd Joergensen, P.; Wegger, I.
1976-01-01
Zinc and myoglobin content in muscles from pigs were studied under various conditions. Zinc concentration was considerably higher in red than in white muscles. In muscles, where the metabolic pattern changes from glycolytic to oxidative during the period from birth to weaning, a simultaneous increase in zinc content was seen. A significant positive correlation exists between myoglobin and zinc content under normal conditions. However, while myoglobin concentration decreases due to iron deficiency anaemia no changes occur in zinc content. It is concluded that no functional link seems to exist between zinc metabolism and myoglobin synthesis in porcine muscles. (author)
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Mass-induced instability of SAdS black hole in Einstein-Ricci cubic gravity
Myung, Yun Soo
2018-05-01
We perform the stability analysis of Schwarzschild-AdS (SAdS) black hole in the Einstein-Ricci cubic gravity. It shows that the Ricci tensor perturbations exhibit unstable modes for small black holes. We call this the mass-induced instability of SAdS black hole because the instability of small black holes arises from the massiveness in the linearized Einstein-Ricci cubic gravity, but not a feature of higher-order derivative theory giving ghost states. Also, we point out that the correlated stability conjecture holds for the SAdS black hole by computing the Wald entropy of SAdS black hole in Einstein-Ricci cubic gravity.
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A blending rule for octane numbers of PRFs and TPRFs with ethanol
AlRamadan, Abdullah S.; Sarathy, Mani; Khurshid, Muneeb; Badra, Jihad
2016-01-01
-gasoline synergistic/antagonistic blending effects. Understanding ethanol blending effects with simpler gasoline surrogates blends may enable a better understanding of ethanol blending with complex multi-component gasoline fuels. This study presents a blending rule
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Teaching Parametric Urban Design in a Blended Learning Format
DEFF Research Database (Denmark)
Steinø, Nicolai
2015-01-01
On the basis of a theoretical discussion of the concept of blended learning, this paper presents the pre- paration, execution and evaluation of a 5 ECTS blended learning course on parametric urban design for a group of some 50 BSc students of architecture and design at Aalborg university...... and curriculum develop- ment, and di culties to nd time for research. Despite the general consensus that developing online/blended learning courses requires both technical support, complex software installations, and substantial preparation time, it is shown that free web ser- vices and low-tech adaptations...... of traditional teaching assets are su cient to get started with blended learning with only little extra e ort. While the pilot blended learning course which provided the insights for this paper has room for impro- vement, it represents a decent rst shot at developing blended learning courses for higher education...
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Defect structure of cubic solid solutions of alkaline earth and rare earth fluorides
DenHartog, HW
1996-01-01
In this paper we will consider the disorder in some cubic solid solutions consisting of one of the alkaline earth fluorides and one of the rare earth fluorides. This is an attractive group of model materials, because these materials have a rather simple overall cubic structure. We will discuss the
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Optimization of the octane response of gasoline/ethanol blends
Badra, Jihad; AlRamadan, Abdullah S.; Sarathy, Mani
2017-01-01
The octane responses of gasoline/ethanol mixtures are not well understood because of the unidentified intermolecular interactions in such blends. In general, when ethanol is blended with gasoline, the Research Octane Number (RON) and the Motor Octane Number (MON) non-linearly increase or decrease, and the non-linearity is determined by the composition of the base gasoline and the amount of added ethanol. The complexity of commercial gasolines, comprising of hundreds of different components, makes it challenging to understand ethanol-gasoline synergistic/antagonistic blending effects. Understanding ethanol blending effects with simpler gasoline surrogates is critical to acquire knowledge about ethanol blending with complex multi-component gasoline fuels. In this study, the octane numbers (ON) of ethanol blends with five relevant gasoline surrogate molecules were measured. The molecules investigated in this study include: n-pentane, iso-pentane, 1,2,4-trimethylbenzene, cyclopentane and 1-hexene. These new measurements along with the available data of n-heptane, iso-octane, toluene, various primary reference fuels (PRF) and toluene primary reference fuels (TPRF) with ethanol are used to develop a blending rule for the octane response (RON and MON) of multi-component blends with ethanol. In addition, new ON data are collected for six Fuels for Advanced Combustion Engine (FACE) with ethanol. The relatively simple volume based model successfully predicts the octane numbers (ON) of the various ethanol/PRF and ethanol/TPRF blends with the majority of predictions being within the ASTM D2699 (RON) and D2700 (MON) reproducibility limits. The model is also successfully validated against the ON of the FACE gasolines blended with ethanol with the majority of predictions being within the reproducibility limits. Finally, insights into the possible causes of the synergistic and antagonistic effects of different molecules with ethanol are provided.
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Optimization of the octane response of gasoline/ethanol blends
Badra, Jihad
2017-07-04
The octane responses of gasoline/ethanol mixtures are not well understood because of the unidentified intermolecular interactions in such blends. In general, when ethanol is blended with gasoline, the Research Octane Number (RON) and the Motor Octane Number (MON) non-linearly increase or decrease, and the non-linearity is determined by the composition of the base gasoline and the amount of added ethanol. The complexity of commercial gasolines, comprising of hundreds of different components, makes it challenging to understand ethanol-gasoline synergistic/antagonistic blending effects. Understanding ethanol blending effects with simpler gasoline surrogates is critical to acquire knowledge about ethanol blending with complex multi-component gasoline fuels. In this study, the octane numbers (ON) of ethanol blends with five relevant gasoline surrogate molecules were measured. The molecules investigated in this study include: n-pentane, iso-pentane, 1,2,4-trimethylbenzene, cyclopentane and 1-hexene. These new measurements along with the available data of n-heptane, iso-octane, toluene, various primary reference fuels (PRF) and toluene primary reference fuels (TPRF) with ethanol are used to develop a blending rule for the octane response (RON and MON) of multi-component blends with ethanol. In addition, new ON data are collected for six Fuels for Advanced Combustion Engine (FACE) with ethanol. The relatively simple volume based model successfully predicts the octane numbers (ON) of the various ethanol/PRF and ethanol/TPRF blends with the majority of predictions being within the ASTM D2699 (RON) and D2700 (MON) reproducibility limits. The model is also successfully validated against the ON of the FACE gasolines blended with ethanol with the majority of predictions being within the reproducibility limits. Finally, insights into the possible causes of the synergistic and antagonistic effects of different molecules with ethanol are provided.
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Sinha, Priyanka; Ubaidulla, U; Hasnain, M Saquib; Nayak, Amit Kumar; Rama, Bobba
2015-08-01
Zinc (Zn(2+))-ion induced diclofenac sodium (DS)-loaded alginate-okra (Hibiscus esculentus) gum (OG) blend beads was successfully formulated through Zn(2+)-ion induced ionic-gelation cross-linking method in a complete aqueous environment. Effects of polymer-blend ratio and cross-linker concentration on drug encapsulation efficiency (DEE) and cumulative drug release at 8 h (R8h) were optimized by 3(2)-factorial design. The optimized formulation of Zn(2+)-ion induced DS-loaded alginate-OG beads demonstrated 89.27±3.58% of DEE and 43.73±2.83% of R8h. The bead sizes were within 1.10±0.07 to 1.38±0.14 mm. The bead surface morphology was analyzed by SEM. The drug-polymer interaction in the optimized bead matrix was analyzed by FTIR and P-XRD. These beads exhibited sustained in vitro drug release over a prolonged period of 8h and followed controlled-release (zero-order) pattern with super case-II transport mechanism. The swelling and degradation of the optimized beads was influenced by the pH of test mediums, which might be suitable for intestinal drug delivery. Copyright © 2015 Elsevier B.V. All rights reserved.