Miracle-dz/UniFAR-FTUs huggingface dataset:
Mixed-Metals Codeposition as a Novel Method for the Preparation of LiMn2 O 4 Electrodes with Reduced Capacity Fades

Mixed-metals codeposition was introduced as an efficient method for the deposition of cathode materials onto substrate surfaces. The approach proposed was typically used for the deposition of LiMn 2 O 4 with codeposition of mixed gold-cobalt. The results obtained for the system under investigation showed that the method employed is applicable for lithium secondary battery performance. In addition to the efficient deposition of the cathode material which is of interest for battery applications, the approach was used to incorporate cobalt oxide into the cathode material. It was demonstrated that the metal oxide deposited with the cathode material significantly reduces the capacity fade of LiMn 2 O 4 in both room and elevated temperatures.
Preparation of CoFe 2 O 4 nanocrystallites by solvothermal process and its catalytic activity on the thermal decomposition of ammonium perchlorate

Nanometer cobalt ferrite (CoFe2O4) was synthesized by polyol-medium solvothermal method and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and selected area electron diffraction (SAED). Further, the catalytic activity and kinetic parameters of CoFe2O4 nanocrystallites on the thermal decomposition behavior of ammonium perchlorate (AP) have been investigated by thermogravimetry and differential scanning calorimetry analysis (TG-DSC). The results imply that the catalytic performance of CoFe2O4 nanocrystallites is significant and the decrease in the activation energy and the increase in the rate constant for AP further confirm the enhancement in catalytic activity of CoFe2O4 nanocrystallites. A mechanism based on an proton transfer process has also been proposed for AP in the presence of CoFe2O4 nanocrystallites.
The thermal stability of graphene in air investigated by Raman spectroscopy

The thermal stability in air of graphene synthesized by either chemical vapor deposition or mechanical cleavage is studied. It is found that single layer graphene prepared by both methods starts to show defects at ~500 °C, indicated by the appearance of a disorder-induced Raman D peak. The defects are initially sp3 type and become vacancy like at higher temperature. On the other hand, bilayer graphene shows better thermal stability, and the D peak appears at ~600 °C. These results are quite different from those annealing in vacuum and controlled atmosphere. Raman images show that the defects in chemical vapor deposition graphene are not homogeneous, whereas those in mechanical cleavage graphene are uniformly distributed across the whole sample. The factors that affect the thermal stability of graphene are discussed. Our results could be important for guiding the future electronics process and chemical decoration of graphene. Copyright © 2013 John Wiley & Sons, Ltd.
Problems associated with spray drying of sugar-rich foods

ABSTRACT Stickiness is a major reason that limits the spray drying of various sugar-rich food products.Higher hygrmopicity of amorphous powder, increase in solubility of sugars with temperature, and lower melting point and glass transition temperature, contribute to the aickiness problem. So far, the glass transition temperature has been widely accepted as a ben indicator for stickiness. There are various manawm that have been applied to spray dry such product. Some of them are the addition of drying aids, modilication of drier design and use of mild drying temperature conditions. This review paper highlights the major research works that deal with the stickiness property of sugar-rich foods.
Electronic Structure of Antiferromagnetically Coupled Dinuclear Manganese (MnIIIMnIV) Complexes Studied by Magnetic Resonance Techniques

The following dinuclear exchange-coupled manganese complexes are investigated: [dtneMnIIIMnIV(μ-O)2μ-OAc](BPh4)2 (dtne = 1,2-bis(1,4,7-triazacyclonon-1-yl)ethane), [(CH3)4dtneMnIIIMnIV(μ-O)2μ-OAc](BPh4)2 ((CH3)4dtne = 1,2-bis(4,7-dimethyl-1,4,7-triazacyclonon-1-yl)ethane), [(CH3)4dtneMnIVMnIV(μ-O)2μ-OAc](ClO4)3, [(tacn)2MnIIIMnIV(μ-O)2μ-OAc](BPh4)2 (tacn = 1,4,7-triazacyclononane), [bpy4MnIIIMnIV(μ-O)2](ClO4)3 (bpy = 2,2‘-bipyridyl), and [phen4MnIIIMnIV(μ-O)2](ClO4)3 (phen = 1,10-phenanthroline). For three of these complexes, X-ray structural data obtained on single crystals are reported here. All complexes are strongly antiferromagnetically coupled, with exchange coupling constants ranging from J = −110 cm-1 (bis-μ-oxo-μ-acetato-bridged) to −150 cm-1 (bis-μ-oxo-bridged). EPR investigations at X- and Q-band frequencies are reported for all five mixed-valence MnIIIMnIV complexes. G tensors and 55Mn hyperfine coupling constants (hfc's) were obtained by simultaneous simulation of the EPR spectra at both fre.
Sorption of Perfluorooctanoic Acid (PFOA) onto Sediment in the Presence of Dissolved Natural Organics

The abundance of perfluorooctanoic acid (PFOA) in the aquatic environment makes it important to understand the influence of important parameters affecting the partition of PFOA onto sediment. With a focus on the influence by dissolved organic matter (DOM), we investigated the sorption of PFOA to river sediment downstream of a semiconductor and optoelectronic industrial complex that discharged wastewater with a considerable amount of PFOA in it. The dominant components of the sediment were silica oxide (∼14%) and iron oxide (∼2%). The sorption density of PFOA was not significantly affected by solution pH and ionic strength. The combinations of low pH-high ionic strength and high pH-low ionic strength favored partitioning of PFOA to the sediment. The sorption density of PFOA to sediment ranged from 0.41 to 1.43 µg/m2, with the presence of DOM in the aqueous phase reducing the affinity of PFOA toward the sediment. The sorption of PFOA seemed to be facilitated not by electrostatic but by hydrophobic interactions. The PFOA-sediment sorption equilibration required a duration exceeding 12 d. This study revealed DOM as an important solution-specific parameter in sorption studies. The influence of DOM on PFOA sorption provides a useful reference to understand PFOA partition in the aqueous environment. Supplemental materials are available for this article. Go to the publisher's online edition of Separation Science & Technology to view the free supplemental file.
Low-temperature graphene growth using epochal catalyst of PdCo alloy

Palladium-Cobalt alloy as a catalyst was introduced to realize low temperature graphene growth on glass substrate by using remote RF plasma-enhanced chemical vapor deposition. Few layer graphene films were easily formed with high transmittance of 88.8% at temperature as low as 400 °C, in good contrast with Ni catalyst in which no graphitic layer was formed at all at the same conditions. High decomposition rate of hydrocarbon gases and formation of nanosize aggregates giving rise to enhancement of carbon incorporation into PdCo alloy and consequently formation of graphene layers at such low temperatures are further discussed with observed Raman spectroscopy and x-ray diffraction.
Characterization of polycrystalline silicon wafers for solar cells sliced with novel fixed‐abrasive wire

For slicing crystalline silicon ingots, we have developed a novel fixed‐abrasive wire where diamond grit is fixed onto a bare wire by resin bonding. The properties of the wafers sliced using a multi‐wire saw with the fixed‐abrasive wire have been investigated. When compared with the wafers sliced with the loose‐abrasive wire, the slicing speed is improved by approximately 2.5‐fold and the thicknesses of saw‐damage layers are reduced by more than a factor of two. Polycrystalline silicon solar cells have been fabricated for the first time utilizing the wafers sliced with the fixed‐abrasive wire, and the cells with the saw‐damage etching depth of 7 µm have shown photovoltaic properties comparable to those prepared using the wafers sliced with the loose‐abrasive wire and subsequently etched to remove the damage layers up to 15 µm. It has been clarified that wafer slicing using the fixed‐abrasive wire is promising as a next‐generation slicing technique for fabrication of solar cells, particularly thin silicon cells where the wafer thicknesses approach or become less than 150 µm. Copyright © 2010 John Wiley & Sons, Ltd.
Treatment of actual metalworking wastewaters by coagulation combined with electrochemical oxidation

The technical and economical viability of physico-chemical treatment followed by electrochemical oxidation of two actual wastes produced in a metalworking industry has been studied. The physico-chemical process was found to be able to achieve the breakdown of the emulsions in the treatment of both effluents, although it requires a complementary treatment to deal with the soluble organic matter. The electrochemical oxidation with Boron-Doped Diamond (BDD) anodes was able to obtain the complete mineralisation of the soluble organic matter. The economic evaluation confirmed that the combination of the coagulation? flocculation with the electrochemical oxidation is viable from the economical point of view.
ACCUMULATORS AND EXCLUDERS ?STRATEGIES IN THE RESPONSE OF PLANTS TO HEAVY METALS

Abstract Plants colonizing metalliferous soils have evolved physiological mechanisms which enable them to tolerate metal toxicity. These mechanisms do not generally suppress metal uptake but result in internal detoxification. Two basic strategies of plant response are suggested, accumulators and excluders. In the former, metals can be concentrated in plant parts from low or high background levels. By contrast, differential uptake and transport between root and shoot in excluders, lead to more or less constant low shoot levels over a wide range of external concentration. ‘Indicators’ are seen as a further mode of response where proportional relationships exist between metal levels in the soil, uptake and accumulation in plant parts. The physiological properties of accumulator and excluder species are considered in relation to metal tolerance mechanisms.
Nonsingular sorption of organic compounds in soil: the role of slow kinetics.

Nonsingular sorption-desorption behavior of organic compounds has been frequently observed, but it remained unexplained in many cases. In this study we investigate the role slow kinetics may play in nonsingular sorption. Sorption-desorption experiments were carried out with the herbicide chortoluron (3-(3-chloro-p-tolyl)-1,1-dimethylurea) and two soils—a silt loam and a loamy sand—using three different batch techniques. The first technique is the classic decantrefill method where part of the supernatant is replaced with solute-free solution. The second technique is similar;, however, part of the supernatant is replaced with solute containing solution instead. In the third technique desorption is induced by successive dilution of the supernatant with time. Nonsingular sorption of chlortoluron was observed independent of the method. We fitted a kinetic two-stage model to the data of the first technique to estimate sorption rate parameters. With this set of parameters, the model predicted the data measured with the second and third technique well. The agreement indicates that nonsingularity phenomena observed by means of the different techniques may be explained by slow sorption kinetics. The ability of the model to describe nonsingular sorption-desorption data was further tested on data sets taken from the literature where nonsingularity remained unexplained or was explained by other causes different from slow kinetics. All phenomena observed in the different studies could readily be explained by the two-stage model.
Review of Microbial Processes in the Near-Surface Environment and Their Implications for the Chemical Fingerprinting of Hydrocarbon Fuels

The chemical composition of middle-distillate fuels released in the subsurface environment is predominantly affected by biochemical processes resulting in selective degradation of hydrocarbons by indigenous microorganisms. The resulting progression in pattern recognition-based fingerprints depends on the composition of the hydrocarbon product, parameters of the product release (e.g., quantity and rate of release) and environmental conditions. The changes for saturated hydrocarbons follow a common sequence of removal of different compound classes: n-alkanes > isoalkanes > alkylcyclohexanes, with a systematic relationship between decreasing relative degradation rates and increasing chain length. However the timescale of these transformations is defined by the subsurface redox condition. Aerobic biodegradation of saturated hydrocarbons can be observed on a relatively short timescale of years to decades, whereas anaerobic degradation is a much slower process. The fact that aerobic biodegradation produces measurable changes in n-alkane concentrations within this timescale makes it a logical option for evaluating time elapsed since a fuel release into the subsurface environment. This paper provides the synopsis of major modes and pathways of biodegradation processes in the near-surface environment and their effect on the temporal changes in the fingerprints of middle-distillate fuels. In particular, a linear decrease in n-alkane concentrations with time allows for the time of fuel release estimates, utilizing the zero-order kinetics model for the Christensen and Larsen method. This model also allows for establishing applicability limits of this approach. The model is relevant only for hydrocarbon contamination in unsaturated (vadose) zone soil where the availability of sufficient concentration of molecular oxygen favors aerobic biodegradation.
Photocatalytic Oxidation of Triiodide in UVA-Exposed Dye-Sensitized Solar Cells

UVA irradiation of glass mounted dye-sensitized solar cells without UV filtration causes failure within 400 hours of light exposure. The failure mode is shown to relate to consumption of I3−, which is directly related to TiO2 photo-catalysis. The onset of failure is easily determined from electrochemical impedance data where the recombination resistance of the TiO2/electrolyte back reaction drops markedly prior to the onset of degradation. At the point of complete cell failure this impedance value then dramatically increases as there is no longer an interfacial reaction possible between the TiO2 and the I3− depleted electrolyte. Device failure is most rapid for cells under electrical load indicating that the degradation of the electrolyte is related to photogenerated hole production by excitation of the TiO2. Once depleted by UV exposure, the I3− can be regenerated by simple application of a reverse bias which can restore severely UV degraded devices to near original working conditions.
Electrochemical Desorption and Adsorption of Nonyl Mercaptan at Gold Single Crystal Electrode Surfaces

The electrochemical behavior of a nonanethiol layer adsorbed on Au(111), Au(110), and on a Au polycrystal has been examined using cyclic voltammetry. The reductive desorption and the oxidative redeposition of the nonanethiol molecules at the Au(111) surface have been shown to depend strongly on the pH of the electrolyte solutions. While the amount of material reductively desorbed from the surface on the first cathodic cycle is independent of the pH, the amount of material that is oxidatively redeposited increases significantly as the pH is lowered. This behavior is ascribed to a reduction in solubility of the product of desorption (thiolate or thiol) as pH decreases. At high pH the redeposition of the layer seems to occur in one step, but at pH values that are lower than the pKa of the nonanethiol the redeposition seems to occur in two steps. In an alkaline solution, the reductive desorption of the nonanethiols from a Au(110) surface is similar to the same process at the Au(111) surface. The double layer .
Imaging retinal nerve fiber bundles at ultrahigh-speed and ultrahigh-resolution using OCT with adaptive optics

Ultrahigh speed line scan detectors based on CMOS technology have been recently demonstrated in ultrahigh resolution spectral-domain optical coherence tomography (UHR-SD-OCT) for retinal imaging. While successful, fundamental tradeoffs exist been image acquisition time, image sampling density, and sensitivity, all of which impact the extent of motion artifacts, visualization of fine spatial detail, and detection of faint reflections. Here we investigate these tradeoffs for imaging retinal nerve fiber bundles (RNFBs) using UHR-SD-OCT with adaptive optics (AO). Volume scans of 3°x3° and 1.5°x1.5° were acquired at retinal locations of 3° nasal and 6° superior to the fovea on a healthy subject. Dynamic AO compensation across a 6 mm pupil provided near-diffraction-limited performance. The acquisition rates were 22.5k lines/s and 125k lines/s with A-lines spaced at 0.9 μm and 1.8 μm and B-scans at 1.8 μm and 9 μm. Focus was optimized for visualizing the retinal nerve fiber bundles (RNFBs). En face projection and crosssectional views of the RNFBs were extracted from the volumes and compared to images acquired with established conventional CCD-based line-scan camera. The projection view was found highly sensitive to eye motion artifacts, yet could only be partially compensated with coarser sampling, since fine sampling was necessary to observe the microscopic features in the RNFBs. For the cross-sectional view, speckle noise rather than eye motion artifacts limited bundle clarity. The highest B-scan density (1.8 μm spacing) coupled with B-scan averaging proved the best combination. Regardless of view, the higher line rate provided better RNFB clarity.
Hydrogen-induced buckling of Mo(110) at submonolayer coverage

The adsorption phase Mo(110) - is structurally analysed by means of low-energy electron diffraction (LEED). A close theory - experiment fit (Pendry R-factor R = 0.16) allows the determination of both a near-threefold-coordinated adsorption site and the detailed reconstructive atomic movements induced in the substrate. The latter are rather complex: in the top Mo layer, hydrogen-coordinated atoms are pulled out of the surface with respect to uncoordinated atoms, leading to a total layer buckling amplitude of 0.06 ? The second substrate layer is also buckled (0.03 ? ) with, however, the Mo atoms below the hydrogen atoms pushed into the surface. The first two interlayer distances relax in the direction of the bulk-like-terminated substrate, as frequently observed for hydrogen-covered surfaces. Yet, compared to the case for Fe(110) - , the induced buckling of top-layer substrate atoms is different in sign (though similar in magnitude), in spite of practically the same adsorption site being obtained, the structural symmetry of the substrate being the same, and the same sign of work-function change being involved. This indicates a delicate balance between structural and electronic material-specific properties.
19F NMR Spectra and Structures of Halogenated Porphyrins

Fluorine-19 NMR spectra of a series of halogenated porphyrins have been used to create a spectral library of different types of fluorine splitting patterns for tetrakis(pentafluorophenyl) porphyrins (TFPP) complexed with diamagnetic and paramagnetic metal ions. The paramagnetic shift, line broadening, and fine structure of the resonances form the peripheral pentafluorophenyl rings are dependent on the symmetry and core environment of the porphyrin macrocycles. In combination with crystal structure data, {sup 19}F NMR helps define the behavior of halogenated porphyrins in solution. Six new crystal structures for TFPP and octahalo-TFPP derivatives are reported: H{sub 2}TFPP in rhombohedral space group R3, a = 20.327(4) {Angstrom}, c = 15.261(2) {Angstrom}, {beta} = 103.87(2){degrees}, V = 2227.6(13) {Angstrom}{sup 3}, Z = 2; CuTFPP in rhombohedral space group R3, a = 20.358(5), c = 14.678(2) {Angstrom}, {alpha} = 88.97(1), {beta}=76.05(1){degrees}, {gamma} = 71.29(1){degrees}, V = 2181.4(6) {Angstrom}{sup 3}, Z = 2; ZnTFPPCl{sub 8} in tetragonal space group P42, c, a = 19.502(20), c = 10.916(8) {Angstrom}, V = 4152(6) {Angstrom}{sup 3}, Z = 2; H{sub 2}TFPPBr{sub 8} in monoclinic space group C2, a = 27.634(6) {Angstrom}, b = 6.926(2) {Angstrom}, c = 14.844(3) {Angstrom}, {beta} = 109.64(2){degrees}, V = 2675.8(11) {Angstrom}{sup 3}, Z = 2.
Novel Adsorbent Hydrous Bismuth Oxide for the Removal of Nitrate from Aqueous Solutions

AbstractHydrous bismuth oxides (HBOs) have the sorptive property to remove nitrate from water. HBOs are also efficient in removing other competitive anions like bicarbonates and sulfates from water. To use HBOs as sorptive filtration media, their characteristics in terms of crystallinity and particle size are important. The objective of this study was to explore the kinetic and equilibria study of HBOs for the removal of nitrate from water. For the present study, three hydrous bismuth oxides, HBO1, HBO2, and HBO3, were prepared under increasing volumetric presence of hydroxide. Both HBO2 and HBO3 were found to be almost equally efficient for nitrate removal from aqueous solutions. Because HBO2 is a superior bismuth oxide, kinetic and equilibrium studies were performed with HBO2. X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM) techniques were used to characterize the adsorbents. The pH of point of zero charge (pHPZC) of the HBOs also supported.
Use of Degradation Rates of DDT and Lindane Isomers for Determining the Timing of Release to Sediments of Greens Bayou: Houston Ship Channel, Texas

Sediments collected from Greens Bayou, a tributary to the Houston Ship Channel, in Houston, Texas, were collected and analyzed in a laboratory study designed to determine anaerobic degradation rates for DDT and lindane isomers in the Bayou. This site-specific degradation data was then used to estimate the time period during which DDT and lindane were released to Greens Bayou from a former chemical manufacturing plant site. Initial DDT concentrations of 100–1,000 μg/kg degraded to nondetectable levels within 8 days. Initial lindane concentrations of 250–2,500 μg/kg degraded preferentially according to isomeric structure: Alpha BHC (α-BHC), Beta BHC (β-BHC), and Gamma BHC (γ-BHC) had half-lives ranging from 1–5 days. Delta BHC (Δ-BHC) had half-lives ranging from 22–30 days. It was concluded that any discharges of DDT or lindane prior to 1971 into Greens Bayou from the chemical manufacturing plant at sediment concentrations less than 2,500 μg/kg would have degraded long prior to 1983. Persistent DDT or lindane detected at significant levels in Greens Bayou sediments today could not have been deposited in sediments until many years after 1983 and must have been deposited at concentrations or loading levels high enough to have a toxic effect on the sediment's anaerobic degradation capacity.