Miracle-dz/UniFAR-FTUs huggingface dataset:
Silylation of mechanically ground kaolinite

Abstract Silylated kaolinites were synthesized at 80ºC without the use of inert gas protection. The method presented started with mechanical grinding of kaolinite, followed by grafting with 3- aminopropyltriethoxysilane (APTES). The mechanical grinding treatment destroyed the ordered sheets of kaolinite, formed fine fragments and generated broken bonds (undercoordinated metal ions). These broken bonds served as new sites for the condensation with APTES. Fourier transform infrared spectroscopy (FTIR) confirmed the existence of -CH2 from APTES. 29Si cross-polarization magic-angle spinning nuclear magnetic resonance spectroscopy (29Si CP/MAS NMR) showed that the principal bonding mechanism between APTES and kaolinite fitted a tridentate silylation model (T3) with a chemical shift at -66.7 ppm. The silane loadings of the silylated samples were estimated from the mass loss obtained by TG-DTG curves. The results showed that the 6-hour ground kaolinite could be grafted with the most APTES (7.0%) using cyclohexane as solvent. The loaded amount of APTES in the silylated samples obtained in different solvents decreased in the order as: nonpolar solvent > polar solvent with low dielectric constant (toluene) > polar solvent with high dielectric constant (ethanol).
Synthesis and molecular structure analysis of nano‐sized methacryl‐grafted polysiloxane resin for fabrication of nano hybrid materials

The molecular structures of methacryl-grafted polysiloxane resins from 3-(trimethoxysilyl)propyl methacrylate (MPTS) and diphenylsilanediol (DPSD) were determined by theoretical computation and experimental measurement. The molecular structures obtained from theoretical computation coincided well with those from experimental measurement, and we found that the structural changes in the resins could be controlled by precursor compositions. While molecular weights and polysiloxane chain lengths of the resins increase with DPSD contents, their molecular sizes do not vary significantly. In the present study, molecular sizes and shapes of the resins with various compositions are hypothesized theoretically and proven experimentally. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 827–836, 2005
Synthesis of green-emitting Pt 8 nanoclusters for biomedical imaging by pre-equilibrated Pt/PAMAM (G4-OH) and mild reduction

We synthesized green-emitting platinum (Pt) nanoclusters (excitation: 460 nm, emission: 520 nm) by reducing Pt ions from pre-equilibrated Pt/fourth-generation poly(amidoamine) dendrimers (PAMAM (G4-OH)) complexes with a mild reductant. The structural characteristics of the resulting Pt nanoclusters, Pt8L8 (L = C2H2O2S), were determined by Electrospray ionization (ESI) mass spectroscopy. These nanoclusters possess a 28% quantum yield, which is higher than those of green-emitting Au and Ag nanoclusters. We also found that Pt nanoclusters have considerably low cytotoxicity and biocompatibility, and demonstrated that they could be used for biomedical imaging. This study provides the possibility to extend the photoluminescent wavelength of Pt nanoclusters to the near infrared region, which is ideal for biological imaging applications.
Unraveling the Morphology of High Efficiency Polymer Solar Cells Based on the Donor Polymer PBDTTT‐EFT

The microstructure of the polymer PBDTTT‐EFT and blends with the fullerene derivative PC71BM that achieve solar conversion efficiencies of over 9% is comprehensively investigated. A combination of synchrotron techniques are employed including surface‐sensitive near‐edge X‐ray absorption fine structure (NEXAFS) spectroscopy and bulk‐sensitive grazing‐incidence wide angle X‐ray scattering (GIWAXS). A preferential “face‐on” orientation of PBDTTT‐EFT is observed in the bulk of both pristine and blend thin films, with π–π stacking largely normal to the substrate, which is thought to be beneficial for charge transport. At the surface of the blend, a slight “edge‐on” structure of the polymer is observed with side‐chains aligned normal to the substrate. The effect of the solvent additive 1,8‐diiodooctane (DIO) on solar cell efficiency and film microstructure is also investigated, where the addition of 3 vol% DIO results in an efficiency increase from ≈6.4% to ≈9.5%. GIWAXS studies indicate that the addition of DIO improves the crystallization of the polymer. Furthermore, atomic force microscopy and transmission electron microscopy are employed to image surface and bulk morphology revealing that DIO suppresses the formation of large PC71BM aggregates.
Measurement of structural and optical band gaps of Cd1-xZnxS (x = 4 and 6) nanomaterials

The sulphides of cadmium and zinc are widely used materials due to their suitable energy band gaps. Their energy band gap depends on the particle size. The materials have been prepared using a simple solution of CdCl 2 and ZnCl 2 mixed in proper ratio without use of thiophenol. Precipitate of CdZnS is obtained by passing H 2 S, liberated from heated thiourea through this solution. It is confirmed by X-ray diffraction (XRD) and optical band gap estimation that materials prepared are nano-materials. The optical band gap of these materials has been determined in order to establish a relationship between energy band gap of bulk and nanomaterial. It has been noticed that optical band increases with the increase of Zn concentration in CdZnS.
Sedimentation–diffusion equilibrium of binary mixtures of charged colloids including volume effects

We describe the sedimentation–diffusion equilibrium of binary mixtures of charged colloids in the presence of small ions and for non-dilute conditions, by extending the work of Biben and Hansen (1994 J. Phys.: Condens. Matter 6 A345). For a monocomponent system, they included a Carnahan–Starling hard-sphere correction and a pressure term due to the small ions. We extend this approach to mixtures of spheres of unequal size, and implement the fact that the effective buoyant mass of a particle is based on the difference in mass density between the particle itself and the local average mass density, and not on the difference with the mass density of the pure liquid. Without the three volume effects (hard-sphere repulsion, ion pressure, buoyant particle mass based on local, average, mass density), the lighter particle (buoyant mass mL, charge zL) only levitates from the bottom (with a maximum in concentration displaced upwards) when zL/mL> zH/mH (with H indicating the heavier particle). With these volume effects included the fractionation is much sharper and occurs even for . For certain parameter settings we find a bimodal distribution of the heavier particles with most of them in the bottom region, but with a small fraction forming a thin layer higher up in the column. This second layer is not found when the buoyant particle mass is based on the mass density difference with the pure liquid and/or when the ion pressure is neglected, suggesting that it is due to a subtle interplay between these two contributions.
Ferroelectric properties of vinylidene fluoride copolymers

Abstract Ferroelectric properties of copolymers of vinylidene fluoride with trifluoroethylene and tetrafluoroethylene are described with special interest in their polarization reversal and phase transition behavior. The ferroelectric phase consists of all-trans molecules packed in a parallel fashion while molecules adopt irregular TT, TG, T[Gbar] conformations in the paraelectric phase. In the ferroelectric phase, polarization reversal occurs at very high fields (> 100 MV/m) as a result of eventual 180° rotations of individual chain molecules around their axes. The switching time ranges from sec to nsec depending upon the strength of the applied field according to an exponential law with a particularly large activation field (∼ 1 GV/m). The value of the observed remnant polarization is consistent with prediction from a simple dipole sum implying a minor contribution from the Coulomb interaction. The ferroelectric-to-paraelectric transition appears most clearly for copolymers containing 50-80 mol% vinylide.
Investigation of the chemical vapor deposition of silicon carbide from tetramethylsilane by in situ temperature and gas composition measurements

The chemical vapor deposition (CVD) of silicon carbide (SiC) from tetramethylsilane Si(CH{sub 3}){sub 4} (TMS) on a graphite susceptor at 1200-1500 K is studied in a low pressure ({approx}100 Pa) cold-wall reactor under laminar flow conditions. In addition to material characterization (electron microscopy and chemical analysis), the gas-phase temperature distribution and composition are investigated by combining several in situ and ex situ diagnostics. Coherent anti-Stokes Raman spectroscopy (CARS) on TMS and H{sub 2} (produced from TMS decomposition) in the hot zone of the reactor gives the rotational temperature distribution of the molecules and their concentrations. Within a few mean free paths from the surface, the H{sub 2} gas temperature is lower than the surface temperature. This is due to nonunity accommodation coefficient {alpha} of H{sub 2} on SiC. A simple analytical model yields {alpha} = 0.05 for H{sub 2} on SiC. Using gas transport coefficients and the experimental value of {alpha} for H{sub 2}, a two-dimensional numerical code is used to compute the gas flow and temperature profiles in the reactor. The increase of the H{sub 2} concentration and the decrease of TMS concentration close to the surface reveals that gas-phase pyrolysis of TMS occurs within a few millimeters frommore » the hot surface. The gas composition at the outlet of the reactor is analyzed by mass spectrometry and IR absorption spectroscopy. The global gas conversion and material balance between deposited SiC, powders, and exhaust gases is obtained Si atoms of TMS molecules are mostly converted into solid SiC and powders. In the gaseous products a small fraction of trimethylsilane SiH(CH{sub 3}){sub 3} is detected. Other gases in decreasing order of importance are H{sub 2}, CH{sub 4}, C{sub 2}H{sub 4}, and C{sub 2}H{sub 2}. These results are compared with predictions of some thermodynamic models and chemical mechanisms reported in the literature. 42 refs., 15 figs., 5 tabs. « less
Tip Leakage Flow in Linear Compressor Cascade

Tip leakage flow in a linear compressor cascade of NACA 65-1810 profiles is investigated, for tip clearance levels of 1.0, 2.0 and 3.25 percent of chord at design and off-design flow conditions. Data, velocity and pressures, are collected from three transverse sections inside tip clearance and sixteen sections within flow passage. Tip separation vortex influence is identified from the data. Leakage flow mixing is clearly present inside the clearance and has a significant influence on the internal loss.Copyright © 1993 by ASME
Hyperspectral Raman Microscopic Imaging Using Powell Lens Line Illumination

The design and characterization of a simple and robust hyperspectral Raman line imaging illumination system with the use of a Powell lens is reported. The generated line uniformity is ±5% of total intensity with a laser power density of 12 mW/μm2 at the sample with a 50×/0.8 NA (numerical aperture) objective. Similar results were obtained by using other objectives. Linewidths remained near the diffraction limit for all objectives tested. Significant decreases in image acquisition time are also reported with the use of a Powell lens-illuminated hyperspectral Raman line imaging microscope equipped with an intensified charge-coupled device (CCD) detector. Hyperspectral images (100 × 350 pixels) were acquired in as little as 8 with a corresponding signal-to-noise ratio of 24.
Convenient synthesis, characterization of some novel subs-tituted 3-methyl-2-pyrazoline-5-ones and substituted 3,5-dimethyl pyrazoles

Some of the pyrazolones and pyrazoles bearing different functional groups, substituted pyrazolones were synthesized by the condensation reaction of newly synthesized substituted thio- semicarbazide (1a, 2a) with substituted ethyl aceto hydrazone (a 1 -g 1 ) in the presence of glacial acetic acid as a catalyst, they are coloured solid, having high melting points. Substituted pyrazoles have been synthesized by the condensation of newly synthesized substituted thiosemicarbazide (1a, 2a) with substituted phenyl benzene-azo acetyl acetone hydrazone (a 2 - i 2 ) and glacial acetic acid used as a medium in all condensation reactions. The constitution of the newly synthesized substituted pyrazolones and substituted pyrazoles are characterized by their physical properties, elemental analysis, spectral studies like IR.
Spectroscopic analysis of amyloid fibril formation in SH3‐domains

The aggregation of proteins in fibrillar form is a problem of critical importance in a wide range of abnormal disease states. To decipher the molecular mechanism of formation of protein fibrillar aggregates we have chosen to study as model SH3 domains that exhibit different abilities to polymerize into amyloid fibrils. While being not related to any known disease, the SH3 domain of the p85α subunit of phosphatidylinositol 3 kinase has been found to form amyloid fibrils in vitro under acidic conditions, meanwhile, we have found that the spectrin SH3‒domain, sharing the same fold and some sequential identity keeps its native conformation under the same conditions. The use of spectroscopic methods to study these properties is illustrated in the present job, and correlated to direct sample observation by electron microscopy.
Fixation of Amine Copper Preservatives. Part 1. Reaction of Vanillin, a Lignin Model Compound with Monoethanolamine Copper Sulphate Solution

Summary The fixation reaction of copper-ethanolamine preservatives in wood was studied using the reaction between vanillin, a lignin model compound, and ethanolamine-copper sulphate solution. The green compound precipitated after the reaction has been characterized spectroscopically as di(ethanolamine)-bis (vanillinato)dicopper(II); [Cu(vanillin) (ethanolamine)]2. Single crystal X-ray crystallographic studies showed that the crystals of [Cu(vanillin)(ethanolamine)]2 are triclinic with the space group P1 with a = 9.1271(7), b = 10.8723(9), c = 6.360(1) Å, α = 97.08(1), β = 100.63(1), and γ = 110.024(7)°. Z = 1. The binuclear molecule has crystallographic inversion symmetry. The ligand arrangement around the Cu(II) is a distorted square based pyramid, with a base plane made up of two oxygen atoms from the ethanolamine ligands, one oxygen atom from a hydroxyl group in vanillin and one nitrogen atom from ethanolamine. Two Cu-O [1.916(2) and 1.950(5) Å], one Cu-O (hydroxyl) [1.926(4) Å] and one Cu-N [1.999(3) Å] bonds form a plane with Cu-O (methoxyl) [2.303(2) Å] bond in an axial direction at an angle 77 ° to the plane. The result suggests that after treatment with copper-ethanolamine wood preservatives, stable copper-nitrogen-lignin complexes can be formed through reaction with guaiacyl units in lignin.
Distributed Training of Graph Convolutional Networks

The aim of this work is to develop a fully-distributed algorithmic framework for training graph convolutional networks (GCNs). The proposed method is able to exploit the meaningful relational structure of the input data, which are collected by a set of agents that communicate over a sparse network topology. After formulating the centralized GCN training problem, we first show how to make inference in a distributed scenario where the underlying data graph is split among different agents. Then, we propose a distributed gradient descent procedure to solve the GCN training problem. The resulting model distributes computation along three lines: during inference, during back-propagation, and during optimization. Convergence to stationary solutions of the GCN training problem is also established under mild conditions. Finally, we propose an optimization criterion to design the communication topology between agents in order to match with the graph describing data relationships. A wide set of numerical results validate our proposal. To the best of our knowledge, this is the first work combining graph convolutional neural networks with distributed optimization.
Effect of strainer type, spray pressure, and orifice size on the discharge coefficient of standard flat-fan nozzles

The aim of this study was to determine the effect of nozzle strainer type (cylindrical, ball check, slotted, and cup screen type), spray pressure, and nozzle orifice size on the discharge coefficient (C d ) of standard flat-fan nozzles of different nominal sizes (from 02 to 06) and 110° spray angle. The flow rates measured for each nozzle orifice size and strainer type combinations were determined at five different spray pressures (2.0, 3.5, 5.0, 6.5, and 8.0 bars). In the study, size, shape, and area measurements concerned with nozzle geometry were performed and the differences between nozzles of different nominal sizes were revealed. Some of these data were also used to determine the liquid inlet and outlet velocity, discharge coefficient, and minimum spray pressure required for the atomization of nozzles with different strainer types. The liquid inlet and outlet velocity ranged from 4.38 to 11.75 m s -1 and 20.49 to 41.72 m s -1 , respectively, depending on the spray pressures. The nozzles used with the cup screen and slotted strainers had identical velocity data as the same nozzles without strainers. The cylindrical and ball check strainers had a limiting effect on liquid inlet and outlet velocity, especially for 04 and 06 sizes. The C d means of the nozzles with cup screen and slotted strainers, and of those without strainers, ranged from 0.874 to 0.980, and the differences between their means were found to be statistically insignificant for each spray pressure and orifice size. The C d means of the nozzles with cylindrical and ball check strainers were 0.850-0.961 and 0.811-0.963, respectively. The C d of the standard flat fan nozzles without strainer had a tendency to decrease with the increasing spray pressure, while the C d means of the nozzles with ball check strainer moderately increased. For the complete atomization, the minimum pressure requirements of the orifices of 02 and 06 size without strainer were 2.03 and 0.99 bars, respectively, corresponding to flow rates of 0.64 and 1.33 L min -1 . The required spray pressure for the nozzle with ball check strainer was found to be higher than that of the other strainer types.
Gd-doped iron-oxide nanoparticles for tumour therapy via magnetic field hyperthermia

Gd-doped iron oxide nanoparticles were developed for use in tumour therapy via magnetic fluid hyperthermia (MFH). The nanoparticle composition was Gd0.02Fe2. 98O4 as determined by ICP-AES. TEM image analysis showed the primary particles to be about 13 nm in diameter. The specific power adsorption rate (SAR) determined with a field strength of 246 Oe and 52 kHz was 36 W per gram of Fe. This value is about 4 times higher than the reported SAR values for Fe3O4. The heating rate for the nanoparticles in vivo and the potential for tumour therapy were determined in a mouse model. The mouse models treated with doped iron oxide displayed much slower tumour growth, the tumour doubled its mass after 7 days post-treatment compared to 4 days for those models treated with standard iron oxide or saline solution.
A novel method for the development of a carbon quantum dot/carbon nitride hybrid photocatalyst that responds to infrared light irradiation

A novel method has been developed to combine carbon quantum dots (CQDs) with carbon nitride at 450 °C to synthesize an infrared-responsive photocatalyst. In the hybrid photocatalyst, CQDs act as the light source to upconvert infrared light to visible light, while carbon nitride utilizes the light emitted by CQDs to degrade pollutants.
Synthesis and characterization of well-defined [polystyrene-b-poly(2-vinylpyridine)]n star-block copolymers with poly(2-vinylpyridine) corona blocks

This article describes the synthesis and characterization of [polystyrene-b-poly(2-vinylpyridine)]n star-block copolymers with the poly(2-vinylpyridine) blocks at the periphery. A two-step living anionic polymerization method was used. Firstly, oligo(styryl)lithium grafted poly(divinylbenzene) cores were used as multifunctional initiators to initiate living anionic polymerization of styrene in benzene at room temperature. Secondly, vinylpyridine was polymerized at the periphery of these living (polystyrene)n stars in tetrahydrofuran at −78 °C. The resulting copolymers were characterized using size exclusion chromatography, multiangle laser light scattering, 1H NMR, elemental analysis, and intrinsic viscosity measurements. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3949–3955, 2007
Synthesis of 1.3 Dioxans Related with Ambergris

Abstract An improved preparation of the odoriferous acetal (4aR, 6aS, 10aS, 10bR)-4a,7,7,10a-tetramethylper-hydronaphtho[2, 1-d] [1, 3] dioxin (4) and related products are described. The synthesis of 4 is accomplished in six steps, starting with the readily available sesquiterpene (-)-drimenol (5) (overall yield 19.1%).
New volatile constituents from leaves of Stemodia trifoliata (Link.) Reichb. (Schrophulariaceae)

The leaf essential oils of Stemodia trifoliata (Scrophulariaceae), collected at the same month of two different years (August 2005 and 2006), were analized by GC-MS and GC-FID. A total of 22 volatile components represented by sesquiterpenes and diterpenes was identified. β-Caryophyllene (9.4-15.4%) and caryophyllene oxide (6.2-9.0%) were the major compounds identified in the sesquiterpene fraction, while the diterpenoids 6α-acetoxymanoyl oxide (13.9-23.2%) and 6α-hydroxymanoyl oxide (25.1-29.7%) were the main constituents of the diterpene fraction. The two novel manoyl oxide derivatives had their structures established by means of spectroscopic methods, particularly 1D and 2D NMR. This work describes for the first time the chemical investigation on the volatile composition of S. trifoliata.
A Fundamental Model of Particle Deposition Incorporated in CFD Simulations of an Industrial Milk Spray Dryer

Particle deposition is an important, undesirable problem during the operation of spray dryers. A new mathematical model of particle deposition has been developed and implemented in the computational fluid dynamics (CFD) software FLUENT. The pseudo Ohnesorge number Oh* and Weber number We* have been used to formulate the model to the determine possibility of particle deposition. The reentrainment of the particles back into the dryer chamber was determined according to the wall shear stress. The transient multiphase flow process in an industrial spray dryer that produces around 9 tonnes of milk powder per hour was simulated to validate the deposition model. The numerical results show that reentrainment of particles into the dryer chamber is significant at the chamber walls. The deposition intensity has been found to be higher near the adjunctions of the ceiling wall, the vertical wall, and the conical wall because of smaller wall shear stress. The distribution of wall temperature, Oh* and We*, which has important influence on wall deposition, has been obtained from the numerical results. More experimental and computational work is required for future validations.