Miracle-dz/UniFAR-FTUs huggingface dataset:
Preparation and characterization of polyamide 6 nanocomposites using MWCNTs based on bimetallic Co-Mo/MgO catalyst

Multiwalled carbon nanotubes (MWCNTs) based on bimetallic Co-Mo/MgO catalyst were produced in large scale by catalytic chemical vapor deposition method (CCVD) of methane. X-ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and Raman spectroscopy proved carbon nanotube (CNT) forma- tion. As-produced multiwalled carbon nanotubes (PCNTs) and commercial ones (CCNTs) with the same diameter (10- 20 nm) were melt blended with polyamide 6 (PA6). XRD patterns of nanocomposites showed applying 0.1% of both types of CNTs changed the crystalline structure of neat PA6 from ! /" form to thermodynamically more stable ! -phase structure. Differential scanning calorimetry (DSC) showed both types of CNTs shifted crystallization temperature of about 10-15°C to higher temperature due to the nucleating effect of nanotubes. Furthermore, degree of crystallinity increased by about 30% in some composites, especially for PCNTs. Nanocomposites containing PCNTs exhibited improvements in thermal decom- position temperature in comparison with CCNT nanocomposites. Nanocomposites melt viscosity increased at high CNTs loading due to the filler-matrix entanglements.
Direct Fabrication of Cobalt Oxide Nanoparticles Employing Sucrose as a Combustion Fuel

Combustion method has been used as a fast and facile method to prepare nanocrystalline Co3O4 spinel employing sucrose as a combustion fuel. The products were characterized by thermal analyses (TGA and DTA), X-ray diffraction technique (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques. Experimental results revealed that the molar ratio of fuel/oxidizer (F/O) plays an important role in controlling the crystallite size of Co3O4 nanoparticles. Transmission electron microscopy indicated that the crystallite size of Co3O4 nanocrystals was in the range of 13–32 nm. X-ray diffraction confirmed the formation of CoO phase with spinel Co3O4. The effect of calcination temperature on crystallite size and morphology has been, also, discussed.
Adsorption of Copper Ions and Methylene Blue in a Single and Binary System on Wheat Straw

A natural wheat straw was used as adsorbent for removal of copper and methylene blue (MB) from aqueous solution. A batch system was applied to study the behavior of Cu2+ and MB adsorption in single and binary systems on wheat straw. In the single systems, there was no significant difference in the quantity of MB adsorbed onto wheat straw within a pH range of 4.0 to 10.0. But for Cu2+, the optimal pH is about 5. Kinetic studies indicate that Cu2+ and MB adsorption on the wheat straw follows the Elovich equation. The Cu2+ adsorption isotherm follows the Langmuir and Redlich−Peterson models, while MB adsorption follows the Redlich−Peterson isotherm. The adsorption capacities of Cu2+ and MB at 273 K and pH 5 are (7.05 and 60.66) mg·g−1, respectively. In the binary system, Cu2+ and MB exhibited competitive adsorption. The adsorption of Cu2+ or MB is considerably reduced with an increasing concentration of the other. The quantity of Cu2+ adsorbed is more strongly influenced by MB due to the higher affinity of w.
Effects of Ammonium Toxicity on Nitrogen Metabolism and Elemental Profile of Cucumber Plants

ABSTRACT Aspects of ammonium (NH4 +) toxicity in cucumber (Cucumis sativus L.) were investigated following growth with different N sources [nitrate (NO3 −), NH4 +, or NH4NO3] supplied in concentrations of 1, 5, 10, or 15 mM. Plant dry weights and root: shoot ratios were lower with NH4 +-fed plants than with NO3 −-fed plants. Ammonium accumulated strongly in leaves, stem, and roots when the concentration in the growth medium exceeded 1 mM. The increase in tissue NH4 + coincided with saturation of glutamine synthetase activity and accumulation of glutamine and arginine. Low tissue levels of calcium and magnesium in the NH4 +-fed plants constituted part of the NH4 +-toxicity syndrome. Additions of small amounts of NH4 + to NO3 − -grown cucumber plants markedly increased the growth.
Computer simulations of extractant primary amine N1923 and N1923 hydrochloride salt at water/chloroform interface

A molecular dynamics (MD) simulation has been carried out to investigate the structural and dynamical properties of extractant methyloctadecyl amine (N1923), and its hydrochloride salt at water/chloroform interface. The simulation results show that both N1923 molecule and protonated N1923 ion can self-assembly form a monolayer at the interface like most non-ionic or cationic surfactants. It is not only observed that the headgroup N atom of protonated N1923 ion arranges more tightly and orderly than that of N1923 molecule but also verified that the protonated headgroup of N1923 ion has stronger hydration ability than the polar headgroup of N1923 molecule.
New Stable Icosahedral Al-Cu-Ru and Al-Cu-Os Alloys

A thermodynamically stable quasi-crystalline single phase with an icosahedral structure was found to be formed at atomic compositions of Al65Cu20Ru15 and Al65Cu20Os15 in conventionally solidified and fully annealed states as well as in a rapidly solidified state. The quasi-crystalline nature determined by X-ray diffractometry is the highest for the fully annealed ingot, indicating the existence of a truly equilibrium icosahedral structure. The stable quasi-crystals appear to have a growth morphology of pentagonal dodecahedron with an average size of 0.03 mm in a fully annealed state.
Electronic structures of defective boron nitride nanotubes under transverse electric fields

We investigate the electronic structures of some defective boron nitride nanotubes (BNNTs) under transverse electric fields within density-functional theory. (16,0) BNNTs with antisite, carbon substitution, single vacancy, and Stone-Wales 5775 defects are studied. Under transverse electric fields, the band gaps of the defective BNNTs are reduced, similar to the pristine ones. The energy levels of the defect states vary with the transverse electric field directions, due to the different electrostatic potential shift at the defect sites induced by the electric fields. Therefore, besides electronic structure and optical property engineering, the transverse electric field can be used to identify the defect positions in BNNTs.
Effect of Water Extract Of Tetrapleura Tetraptera (Aidon) On Haematological And Biochemical Parameters in Rats infected With Trypanosoma Brucei

This study investigated whether water extract of Tetrapleura tetraptere has trypanocidal effect against T.brucei in laboratory rats. Studies also examined its effect on the weight, haematological parameters as well as the blood chemical analyses of the infected animals. Results showed that oral administration of the water extract to the infected rats significantly reduced the parasite load, also weight loss was significantly lower in the infected and treated rats than the untreated ones. These positive observations were accompanied by reduced leukocytosis, improved state of anaemia and increased packed cell volume, all of which are indices of recovery from the state of cell toxicity arising from parasitemia. The tolerance of the extract by the animal was evaluated by the determination of the blood chemistries. Results revealed that there was no significant difference in the concentrations of the blood glucose, total protein, uric acid and unconjugated bilirubin in the uninfected but treated rats compared with the "neat" rats which were neither infected nor treated. However, conjugated bilirubin and creatinine values were significantly increased. It was also observed that when the infected animals were treated with the extract, the blood levels of total protein, uric acid, creatinine and unconjugated bilirubin decreased slightly, but consistently, as against the untreated rats. These observations indicate the beneficial effects of the plant extract and suggest that the T. tetraptera may contain active substance(s) which could have therapeutic effect against trypanosome infection. Nigerian Quarterly Journal of Hospital Medicine Vol. 9, No. 1 (1999) pp. 66-70
Pulsradiolytische Beobachtungen über die Reduktion des NO3−‐Ions und über Bildung und Zerfall der persalpetrigen Säure in wäßriger Lösung

Das Nitration reagiert mit dem hydratisierten Elektron zu NO32-. Dieses Teilchen absorbiert maximal bei 2500 A mit = 3,1 ± 103 M−1 cm−1. Seine Leitfahigkeit betragt 137 Ω−1 cm2 mol−1. In alkalischer Losung verschwindet es mit δ1/2 = 12,5 μs nach: NO32- + H2O ± NO2 + 2 OH−. In saurer Losung nimmt es Protonen auf bis zur Erreichung der Gleichgewichte: Das OH-Radikal reagiert mit NO2 zu persalpetriger Saure, HO2NO, mit k = 1,3 · 109 M−1 s−1. Der pK-Wert der persalpetrigen Saure wurde zu 5,3 bestimmt. HO2NO verschwindet nach erster Ordnung aus der Losung, indem sich die undissoziierte Form spontan zu Salpetersaure, HNO3, umlagert, wahrend das Anion der persalpetrigen Saure stabil ist. Die Geschwindigkeitskonstante der Isomerisierung The OH radical reacts with NO2 to yield pernitrous acid, HO2NO, with k = 1.3 · 109 M−1 s−1. The pK value of pernitrous acid was found to be equal to 5.3. HO2NO disappears by first order. The undissociated form spontaneously isomerizes to form nitric acid, HNO3, while the anion is stable. The rate constant of the isomerization HO2NO · HNO3 was found to amount to 1.9 · 103 s−1.
Poly(sodium-4-styrene sulfonate) (PSSNa)-assisted transferable flexible, top-contact high-resolution free-standing organic field-effect transistors

The development of high-integration, flexible and transferable devices is a very important premise to realize authentically wearable applications in the future. Here, we report how to fabricate flexible, free-standing and high-resolution (down to 5 μm) top-contact OFETs based on a polystyrene (PS) dielectric layer. In this process, we use a special sacrificial layer, poly(sodium-4-styrene sulfonate) (PSSNa). It is low-cost, dissolves quickly in water at room temperature and has good compatibility with most organic material processing techniques. With the help of this sacrificial layer, this kind of free-standing transistors can be successfully transferred onto arbitrary substrates. Furthermore, the degradation of the performance of the devices after multiple and successive transfer is tolerated.
Rapid Removal of Cu(II) Ion by Chemically Modified Rubber Wood Fiber

Abstract This article describes a study of the adsorption conditions of Cu(II) ions onto polyacrylamide-grafted rubberwood fiber. Preparation of the adsorbent was carried out via graft copolymerization of acrylamide (Am) onto rubberwood fiber (RWF), using ceric ammonium nitrate as an initiator. Fourier transform infrared spectroscopy was used to confirm the formation of PAm-g-RWF. Various variables affecting the adsorption capacity such as pH of the solution, adsorption time, initial metal ion concentration, and temperature were investigated. Cu(II) was removed by PAm-g-RWF up to 92% from an initial concentration of 10 mg/L at pH 6.0. Kinetic adsorption data can be described by the second-order equation. Equilibrium parameters for adsorption isotherms of the metal ions on the grafted fiber were obtained using the Langmuir and Freundlich models, and the Langmuir model was found to be in better correlation with the experimental data with a maximum adsorption capacity of 142.85 mg/g. Thermodynamic parameters.
Equilibrium structure and lateral stress distribution of amphiphilic bilayers from dissipative particle dynamics simulations

The equilibrium structure and lateral stress profile of fluid bilayer membrane patches are investigated using the Dissipative Particle Dynamics simulation technique. Although there are no attractive forces between the model amphiphiles, they spontaneously aggregate into planar bilayers under suitable conditions of concentration and amphiphile architecture. Pure bilayers of single-chain and double-chain amphiphiles are simulated, and the amphiphile architecture and interaction parameters varied. We find that a strong chain stiffness potential is essential to create the lamellar order typical in natural lipid membranes. Single-chain amphiphiles form bilayers whose lamellar phase is destabilized by reductions in the tail stiffness. Double-chain amphiphiles form bilayers whose rigidity is sensitive to their architecture, and that remain well-ordered for smaller values of their tail stiffness than bilayers of single-chain linear amphiphiles with the same hydrophobic tail length. The lateral stress profile across the bilayers contains a detailed structure reflecting contributions from all the interaction potentials, as well as the amphiphile architecture. We measure the surface tension of the bilayers, and extract estimates of the membrane area stretch modulus and bending rigidity that are comparable to experimental values for typical lipid bilayers. The stress profile is similar to that found in coarse-grained Molecular Dynamics simulations, but requires a fraction of the computational cost. Dissipative Particle Dynamics therefore allows the study of the equilibrium behavior of fluid amphiphilic membranes hundreds of times larger than can be achieved using Molecular Dynamics simulations, and opens the way to the investigation of complex mesoscopic cellular phenomena.
Prenatal Diagnosis of Tetrahydrobiopterin (BH4) Synthase Deficiency

Dept. of Osaka City Univ. Medical School, Osaka 545, Japan * Dept. of Pediatrics Juso Citizens' Hospital, Osaka 532, Japan ** First Division of Pediatrics Children's Medical Center of Osaka City, Osaka 537, Japan *** Dept. of Pediatrics PL Hospital, Tondabayashi 584, Japan **** Osaka Municipal Rehabilitation Center for the Disabled, Osaka 547, Japan ***** Veterans General Hospital, Taipei 11216, Republic of China ****** Shanghai Institute for Pediatric Research, Shanghai, China
Structure and energy of the partial dislocation cores in GaAs

A methodology for investigating isolated α and β partial dislocations in III–V semiconductors is presented. Using this method the 30° and 90°, α and β partial dislocations in GaAs are investigated. The structures of the proposed core reconstructions are investigated. For the 90° partials, two reconstructions have been proposed. The relative energies of the two reconstructions are investigated in addition to the structural investigation. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of Microbial Community Structure, Terminal Electron Accepting Conditions, and Molybdate on the Extent of U(VI) Reduction in Landfill Aquifer Sediments

Addition of an electron donor, such as ethanol, glucose, or acetate, to the subsurface in order to stimulate biological reduction of soluble U(VI) to insoluble U(IV) is an important strategy for uranium immobilization in contaminated aquifers. Electron donor addition typically results in anaerobic conditions and the respiratory process (sulfate-reducing, iron-reducing, and/or methanogenic) will depend on site geochemistry. Although previous studies have found that U(VI) reduction can occur under any of these conditions, the goal of this study was to examine the relative extent of U(VI) reduction under different geochemical conditions and the influence of the different microbial populations on the reduction process. Sulfate-reducing (SR), iron-reducing (FeR), and methanogenic (Meth) conditions were stimulated by electron donor addition in sediment batch microcosms, and 100 μM U(VI) was added upon depletion of alternate electron acceptors. Within seven days, 89, 96, and 66% of soluble U(VI) was immobilized by sorption and/or precipitation from sulfate-reducing, iron-reducing, and methanogenic bottles, respectively. After 26 days, however, bicarbonate and nitric acid extractions of solid-associated U(VI) and total U showed that (i) there was no significant difference in the amount of U(VI) reduced between the different terminal electron accepting conditions stimulated in pre-incubations (0.204 ± 0.052, 0.263 ± 0.023, and 0.247 μmol total reduced U(IV) per g dry sediment in SR, FeR, and Meth bottles, respectively); (ii) geochemical conditions formed in FeR bottles contributed most to abiotic U(VI) reduction, with 0.0123 ± 0.0105, 0.0737 ± 0.0111, and 0.0464 ± 0.0002 μmol total reduced U(IV) per g dry sediment in formaldehyde-killed SR, FeR, and Meth bottles, respectively; and, (iii) molybdate inhibited biotic U(VI) reduction to some degree under each terminal electron accepting condition stimulated, with an average of 33% less U(IV) per g dry sediment in live bottles containing molybdate compared to controls. PLFA analysis of sediments showed that different major PLFAs groups were associated with the amount of U(IV) per g dry sediment with each terminal electron accepting condition stimulated during pre-incubations, with positive correlations between monounsaturates and U(IV) in SR bottles (r = 0.926), branched monounsaturates and U(IV) in FeR bottles (r = 0.886), and terminal-branched saturates and U(IV) in Meth bottles (r = 0.999). Collectively, these data suggesting that different populations may have been involved in U(VI) reduction under each condition and that the extent of U(VI) reduction does not differ whether sediments were sulfate-reducing, iron-reducing, or methanogenic prior to U(VI) addition.
σ-Hole Interactions of Covalently-Bonded Nitrogen, Phosphorus and Arsenic: A Survey of Crystal Structures

Covalently-bonded atoms of Groups IV–VII tend to have anisotropic charge distributions, the electronic densities being less on the extensions of the bonds (σ-holes) than in the intervening regions. These σ-holes often give rise to positive electrostatic potentials through which the atom can interact attractively and highly directionally with negative sites (e.g., lone pairs, π electrons and anions), forming noncovalent complexes. For Group VII this is called “halogen bonding” and has been widely studied both computationally and experimentally. For Groups IV–VI, it is only since 2007 that positive σ-holes have been recognized as explaining many noncovalent interactions that have in some instances long been known experimentally. There is considerable experimental evidence for such interactions involving groups IV and VI, particularly in the form of surveys of crystal structures. However we have found less extensive evidence for Group V. Accordingly we have now conducted a survey of the Cambridge Structural Database for crystalline close contacts of trivalent nitrogen, phosphorus and arsenic with six different types of electronegative atoms in neighboring molecules. We have found numerous close contacts that fit the criteria for σ-hole interactions. Some of these are discussed in detail; in two instances, computed molecular electrostatic potentials are presented.
Use of a single sulphuric acid-hydrogen peroxide digest for the analysis of Pinus radiata needles.

Abstract The sulphuric acid‐hydrogen peroxide digest is used extensively for the analysis of N, P, K in plant material. Advantage can be taken of this single digest solution to analyse for Na, Ca, Hg, Fe, Mn, Zn, Cu, and B in Pinus radiata D. Don needles, with only minor modifications to the digestion technique. The results obtained are comparable to those obtained with the nitric‐perchloric acid digestion and dry ashing. The additional operator time involved for the digestion procedure, compared with other digestion mixtures, is compensated for by having only the one digest to process for all elements. One operator can digest and analyse 120 samples for all eleven elements using manual methods in one week.
Interacting Lattice Gas Automaton Study of Liquid-Gas Properties in Porous Media

Nous decrivons comment un automate cellulaire, le gaz sur reseau, peut etre utilise pour simuler les phenomenes d'evaporation dans des modeles de milieux poreux construits a l'echelle du pore. Des simulations bi-dimensionnelles d'evaporation sont realisees dans la geometrie simple du tube et dans un modele de milieu poreux microscopiquement desordonne. Nous decrivons une variante du gaz sur reseau, appele le modele liquide-gaz. A l'aide de tests statiques et dynamiques, nous montrons que ce modele peut simuler les equations mecaniques et thermodynamiques a faible nombre de Reynolds, pour une evaporation isotherme dans un systeme reel compose d'une espece unique sous forme liquide en equilibre avec sa vapeur. A partir des simulations statiques dans des geometries simples, nous obtenons les pressions d'equilibre de part et d'autre d'un menisque. Celles-ci obeissent aux relations de Gibbs-Thomson, relations equivalentes a l'effet Kelvin. Nous observons une evaporation dans des tubes capillaires et comparons les resultats a une theorie simple basee sur le flux de Poiseuille. Un effet inattendu est un flux additionnel dans les films mouillants et de brusques sauts de densite. Dans les simulations d'evaporation en geometries desordonnees, nous observons des avancees par sauts et des interfaces irregulieres, comme deja decrites dans les experiences en laboratoire.
Numerical model of the dynamic absorption variation in QW-EAM for ultrafast all-optical signal processing

Noise reduction techniques, such as all-optical 3R regeneration, can be realised using ultrafast saturable absorbers, both for the clock recovery block and for the reshaping block. Electroabsorption modulators (EAM) can be used as saturable absorbers when they are traversed by a strong pump optical pulse, which can reduce the absorption experienced by a second probe signal that propagates along the device together with the pump: this feature is called cross-absorption modulation (XAM). The authors present a novel numerical model to evaluate the dynamic behaviour of a quantum well EAM absorption, that can be applied in all-optical signal processing schemes for ultrafast transmission systems. The effects of both electric field screening and exciton saturation are taken into account. Numerical results agree with the experimental device behaviour reported in the literature.
Selective Reduction of NOx by Methane on Co-Ferrierites: I. Reaction and Kinetic Studies

Cobalt-exchanged ferrierite zeolite catalysts were found to be very active (about twice the activity compared to Co-ZSM-5) for the selective reduction of NOx with CH4. The presence of oxygen (gaseous O2 or O atoms via N2O decomposition) greatly enhanced the NOx conversion to N2. In the absence of O2, NO2 can be effectively reduced with CH4, but its conversion decreased with increasing temperature at T > 500°C with a formation of small amount of O2. Temperature programmed desorption measurements show that the presence of O2 alters the NO adsorption/desorption on Co-ferrierite, yielding an additional, high-temperature NO desorption peak. Partial pressure dependencies were measured as a function of reaction temperature under both dry and wet conditions. In the absence of added H2O vapor, the empirical reaction order with respect to NO (0.2 to 0.4) increased with increasing temperature with no change in the reaction order for CH4 (0.7). Addition of H2O vapor (2%) significantly increased the empirical reaction orders with respect to both NO (0.7) and CH4 (0.8-0.9). Under wet conditions, the reaction orders are higher at low temperatures. The added H2O vapor also substantially raised the apparent activation energies for both NO reduction and CH4 combustion. The turnover frequencies for both reactions increased with increasing CO2+ level, demonstrating the heterogeneity of the Co2+ sites. The differences in activity and selectivity and in the distribution of active sites between Co-ferrierite and Co-ZSM-5 may be related to the different channel systems of these two zeolites.