Miracle-dz/UniFAR-FTUs huggingface dataset:
Colloidal deposition under conditions of controlled potential

The rate of colloidal deposition of carbon black onto a microscope slide coated with tin-doped indium oxide has been measured using light scattered from the evanescent wave of a light beam passing through the slide. The rate can be measured in real time and the ITO coat allows the electrode potential of the surface to be changed. The mass transport of the particles is controlled by using the hydrodynamics of the impinging jet; depending on the size of the jet the hydrodynamics can either be wall-pipe or wall-jet. When the potential of the surface is positive there is no barrier to the deposition of the negatively charged particles; under both the wall-pipe and wall-jet regimes the particles deposit as the mass transport-controlled rate. Good agreement is found between the values of the diffusion coefficient of the particles measured in the two regimes. Depending on the age of the slide, when the potential is negative the particles either do not deposit or they deposit into the secondary minimum. The radial variation under the wall-jet regime shows that if they do deposit they do so again at the mass transport-controlled rate. The position of the secondary minimum can be calculated and it is shown that there is good agreement between the calculated position and the penetration of the evanescent wave. For ionic strengths > 10 mmol dm–3 there is no barrier and the particles deposit at all potentials. From this result we estimate a value of the Hamaker constant of 23.8 kBT. Using this value one can then calculate for lower ionic strengths the potential at which the barrier collapses and the particles transfer from the secondary into the primary minimum. Reasonable agreement is found between the theoretical and experimental results.
Fibrous active carbons from coir

The production and adsorptive properties of fibrous active carbons produced from coir were investigated using thermogravimetric analysis, gas adsorption, adsorption from solution, mercury porosimetry and electron microscopy. Additions of ZnCl2 to coir increased carbon yield by lowering the temperature of primary carbonisation. Apparent specific surface areas of the carbons lie in the range 435–880 m2 g-1; the carbons are microporous and exhibit strong preferential adsorption of p-nitro-phenol from solution. Macropores in the carbons were identified as interfilamentary voids in the carbon fibre bundles.
High temperature operation of short wavelength InAs-based quantum cascade lasers

InAs/AlSb quantum cascade lasers emitting at 3.06 and 3.22 μm at room temperature has been studied. The lasers with high reflection coating on back facets operated in pulse mode up to 400 and 423 K, respectively. The obtained results showed no dramatic performance degradation of the InAs-based QCLs with decreasing emission wavelength down to 3 μm.
Enzyme‐catalyzed direct electron transfer: Fundamentals and analytical applications

This article overviews the fundamentals of the phenomenon of direct electron transfer in enzyme-catalyzed electrode reactions and the development of electroanalytical applications of the bioelectrocatalytic systems. A brief description of the enzymes capable of catalyzing electrochemical reactions by means of direct electron transfer is given. The physico-chemical background of bioelectrocatalysis is discussed in terms of the different concepts underlying the mechanism of electron transfer. The concept of a “molecular transducer” is introduced to designate a complex, formed by the electrocatalytically active enzyme on the electrode-electrolyte interface, which is directly responsible for the transduction of the chemical signal to an electric one. The role of this “molecular transducer” in enzyme electrodes and immunoelectrodes is discussed. The analytical applications of bioelectrocatalysis are categorized as systems employing either amperometric or potentiometric detection. Discussion focuses on the advantages of systems based on enzyme-catalyzed direct electron transfer as opposed to other enzyme-catalyzed electroanalytical devices. In conclusion, the trends towards upcoming practical applications are suggested as well as some directions in fundamental studies of bioelectrocatalysis as a phenomenon.
Optimization of process factors for the efficient generation of biogas from raw vegetable wastes under the direct influence of plastic materials using Taguchi methodology

Abstract In this investigation, the combined process efficiency with respect to biogas generation was evaluated by Taguchi robust design using raw vegetable wastes (RVW) and waste plastics (WP) as the key components. The signal-to-noise (S/N) ratio was used to estimate the main effects, interaction effects, and optimal levels of the process factors. Among the various experimental combinations, statistical analysis of the optimized result showed that enhanced biogas production could be achieved with the plastic content (15%), height to diameter (h/D) ratio (30), water content (125 ml), and digestion period (18 week). The Taguchi methodology predicted a maximum biogas (24.83 m3/ton of RVW) could be generated with those selected process parameters under optimized condition. The experimental data showed that enhanced biogas production (24.16 m3/ton of RVW) was found with the optimized conditions.
Si(100) surfaces: Atomic and electronic structures

The surface atomic geometries of 2×1 and 4×2 reconstructed Si(100) are determined through energy‐minimization calculations. Many possible structural models were tested. The results show the most favorable geometries for both the 2×1 and 4×2 surfaces to be that of asymmetric, partially ionic dimers. The surface atomic coordinates and electronic structures are discussed.
Chromium(III) Terephthalate Metal Organic Framework (MIL-101): HF-Free Synthesis, Structure, Polyoxometalate Composites, and Catalytic Properties

Hybrid materials of the metal–organic framework (MOF), chromium(III) terephthalate (MIL-101), and phosphotungstic acid (PTA) were synthesized in aqueous media in the absence of hydrofluoric acid. XRD analysis of the MIL101/PTA composites indicates the presence of ordered PTA assemblies residing in both the large cages and small pores of MIL-101, which suggests the formation of previously undocumented structures. The MIL101/PTA structure enables a PTA payload 1.5–2 times higher than previously achieved. The catalytic performance of the MIL101/PTA composites was assessed in the Baeyer condensation of benzaldehyde and 2-naphthol, in the three-component condensation of benzaldehyde, 2-naphthol, and acetamide, and in the epoxidation of caryophyllene by hydrogen peroxide. The catalytic efficiency was demonstrated by the high (over 80–90%) conversion of the reactants under microwave-assisted heating. In four consecutive reaction cycles, the catalyst recovery was in excess of 75%, whereas the product yields were .
A new design for submicron double-barrier resonant tunnelling transistors

A new fabrication technique is described for a submicron vertical AlGaAs/GaAs double-barrier resonant tunnelling transistor which is ideal for investigating single electron charging of, and single electron tunnelling through, a quantum dot containing just a `few' electrons. The electrical characteristics and figures of merit are presented to demonstrate the improved `squeezing' capability of the Schottky gate which is located around, and partially on, the etched side wall of the device mesa after a combined dry and wet etch to a point below the two barriers, and contrasted with those of an earlier design where etching is stopped above the two barriers.
Synthetic routes to Cleistopholine and methylated analogues

Two synthetic pathways have been developed which lead to the natural product cleistopholine (1). One route has been adapted for the synthesis of the methylated analogues 2 and 3. The key step involved nickel-catalyzed regiospecific coupling of benzylic zinc bromides with methyl-2bromo-4-methyl nicotinate (10) to afford benzylated pyridines followed by their subsequent transformations to the benzo[g]quinoline-5,10-diones.
Quantifying Minimum Monolith Size and Solute Dilution from Multi‐Compartment Percolation Sampler Data

Preferential flow affects solute transport in natural soils, leading to high spatiotemporal variation of concentration. A multicompartment solute sampler (MCS), yielding multiple breakthrough curves at a given depth, can monitor tracer movement in a heterogeneous soil. We present a technique to estimate from MCS data whether a soil monolith is sufficiently large to capture preferential flow, which is a necessity for tracer breakthrough curves to be representative. For several soils, we estimate that an MCS should be larger than 0.1 to 0.2 m2 We also expand dilution theory to analyze the concentration variations of a tracer passing the control plane monitored by the MCS, in addition to the conventional plume spreading analysis. We characterize the set of locally observed breakthrough curves by the entropy‐based dilution index. For given first and second‐central moment, the spatially uniform log‐normal breakthrough curve maximizes the dilution index. The ratio between observed and maximum dilution index is denoted reactor ratio. For a 300‐compartment solute sampler, covering an area of 0.75 m2, we compute a reactor ratio of 0.665, compared with 0.04 for stochastic‐convective and 1 for convective‐dispersive transport. With a single, large collector the reactor ratio would be 0.958, severely underestimating concentration variations. Large collector areas are clearly inadequate to estimate dilution. Values of the dilution index and the reactor ratio for individual sampling compartments indicate efficient longitudinal mixing in most but not all cases, and considerable spatial variation of the leaching process.
First passage time approach to diffusion controlled reactions

Association reactions involving diffusion in one, two, and three‐dimensional finite domains governed by Smoluchowski‐type equations (e.g., interchain reaction of macromolecules, ligand binding to receptors, repressor–operator association of DNA strand) are shown to be often well described by first‐order kinetics and characterized by an average reaction (passage) time τ. An inhomogeneous differential equation is derived which, for problems with high symmetry, yields τ by simple quadrature without taking recourse to detailed cumbersome time‐dependent solutions of the original Smoluchowski equation. The cases of diffusion and nondiffusion controlled processes are included in the treatment. For reaction processes involving free diffusion and intramolecular chain motion, the validity of the passage time approximation is analyzed.
PHOTOCONVERSION OF PHYTOCHROME IN VIVO STUDIED BY DOUBLE FLASH IRRADIATION IN Mougeotia AND Avena

Abstract— The kinetics of phytochrome phototransformation from the red‐absorbing form (Pr) to the far‐red‐absorbing form (Pfr) in vivo at 22°C were studied using a double flash apparatus with 1‐ms flashes. Photoconversion by simultaneous flashes of red light saturates at a low Pfr level, indicating the possible attainment of a photoequilibrium between the excitation of Pr and the photoreversion of intermediates in the course of the I‐ms flashes. At saturation energy, simultaneous flashes resulted in about 50% as much Pfr as was produced by saturating irradiation with 5 s red light. Intermediates of the phototransformation pathway were analysed by separating two red or a red and a far‐red flash by variable dark intervals. In both plants phototransformation intermediates with half‐lives < 1 ms occur, but they are too short‐lived to characterize by our method. The subsequent intermediates have half‐lives of about 7 ms and 150 ms in A vena, 2 ms and 10 ms in Mougeotia. The conversion from Pr to Pfr seems to be completed 1 s after the red flash in Avena. In the alga Mougeotia, Pfr formation seems to be finished within only 50 ms after the inducing red flash. The kinetics obtained from physiological and spectrophotometric experiments with Avena mesocotyls are almost identical. These observations indicate that the physiological response corresponds directly to the amount of Pfr produced and not to phototransformation intermediates or “cycling” between Pr and Pfr.
An analytical scattering function for polydisperse spherical core–shell particles with Schulz–Flory size distributions of both core size and shell thickness

The scattering function for polydisperse core–shell particles with Schulz–Flory size distributions of both the core radius and the shell thickness is analytically calculated. The results of the analytical solution are compared with the results of a numerical integration over both size distributions, as well as with available analytical solutions for homogeneous spheres. The CPU time required for the calculation of the scattering function can be reduced by several orders of magnitude compared with numerical integration. This is of tremendous importance in nonlinear curve fitting requiring repeated calculation of the theoretical function in an iterative process.
The effect of plantation silviculture on soil organic matter and particle-size fractions in Amazonia

Eucalyptus grandis and other clonal plantations cover about 3.5 million ha in Brazil. The impacts of intensively-managed short-rotation forestry on soil aggregate structure and Carbon (C) dynamics are largely undocumented in tropical ecosystems. Long-term sustainability of these systems is probably in part linked to maintenance of soil organic matter and good soil structure and aggregation, especially in areas with low-fertility soils. This study investigated soil aggregate dynamics on a clay soil and a sandy soil, each with a Eucalyptus plantation and an adjacent primary forest. Silvicultural management did not reduce total C stocks, and did not change soil bulk density. Aggregates of the managed soils did not decrease in mass as hypothesized, which indicates that soil cultivation in 6 year cycles did not cause large decreases in soil aggregation in either soil texture. Silt, clay, and C of the sandy plantation soil shifted to greater aggregate protection, which may represent a decrease in C availability. The organic matter in the clay plantation soil increased in the fractions considered less protected while this shift from C to structural forms considered more protected was not observed.
Charge Transfer in Charge‐Coupled Devices

The transfer characteristics of charge‐coupled devices have been investigated theoretically and simulated experimentally. The transport of minority carriers along the Si–SiO2 interface can be described by a diffusion equation where the effective diffusion coefficient is composed of two terms representing the drift and the diffusion currents. There are two time constants associated with the two current components. For typical operating conditions, the drift time constant is about 100 times smaller than the diffusion time constant. The charge transfer can theoretically be separated into a charging and a discharging process, and the final stages are described by the drift and the diffusion time constants, respectively. Transfer efficiencies for charge‐coupled devices have been calculated from the discharging phenomena. The drift current increases the transfer efficiency significantly. For high transfer efficiencies (>99%), however, the increase of the transfer efficiency with transfer time is limited by the .
Consolidation recovery of rare/hazardous elements from polluted water by the hydrothermal mineralization process

Detoxification of polluted water is required in many fields of industrial or agricultural production processes. Not only removal of rare/hazardous elements, but also the recovery and effective use of such elements is essential to increase the resource circulation efficiency. Recycling technology of rare metals and hazardous elements from polluted water would bring about our clean and environmentally benign society. The hydrothermal mineralization process is one of the best candidate techniques to meet the above demand. In the present work, we investigated the consolidation recovery of rare/hazardous inorganic compounds containing B, F, P, Cr, As, Sb, etc. The model wastewaters containing the above elements with various concentrations were treated in autoclave under the hydrothermal temperatures of 100-200 o C using Ca(OH)2 or CaCl2 as the mineralizer. Corresponding minerals, such as CaB2O5･H2O, CaF2, Ca5(PO4)3(OH), Ca2CrO4, Ca5(AsO4)3(OH), Ca2(Sb2O7), were consolidated and separated by filtration after the treatments. Solid/liquid separation under hydrothermal equilibrium was found to be very effective for increasing the yield of minerals, because the final concentration in liquid is determined by the solubility of the mineral under the hydrothermal condition. As a result, the concentration of every residual element in liquid decreased below the National Effluent Standard of Japan. The recovered minerals can be supplied as raw materials for the refining process of ordinary minerals. Such a geo-mimetic wastewater treatment method will be applied to the detoxification and recovery of many kinds of rare/hazardous elements in wastewater.
The Dynamics of Concentration of Selected Chemical Components of Rainfalls in the Miedzyzdroje

The development of a business man and also growing up processes the transformative environment adversely affect the individual elements of the natural environment. These processes they realize that individual elements of environmental protection becomes the basis for the further development of socio-economic background. In recent years the increasing pollution of the atmosphere causes more and more interest in the science of the substances contained in it and merge back to the surface of the Earth. Of great importance for the environment have the substances contained in the water drainage, as in the form of dissolved very easily reach the individual environmental elements causing their contamination. Research was carried out in the years 2008-2011 (January-December) in the town of Międzyzdroje. In the tests was measured the amount of precipitation, chemical composition (NH4+, NO3-, PO43-- ions were numbered), pH and conductivity. Międzyzdroje is a city located in the north-western part of the county on the island of Wolin on the Baltic Sea. The city is located on the Bay of Pomorska, in the central part of the coast of the island of Wolin. Part of the East of Międzyzdroje is situated on the western slopes of the remains of the Beautiful. The climate of the island of Wolin is different from the rest of the country because the climate is strongly influenced by the presence of the Baltic Sea. It is characterized by high humidity, sunlight and precipitation variability, wind direction and force large diurnal temperature amplitude. Międzyzdroje is a resort and tourist destination.
Synthesis and Characterization of Nonlinear Nanopores in Alumina Films

Controlled and convenient synthetic approaches for more complex-shaped nanotubes and nanowires of different materials are needed to further advance the field of nanoscience and nanotechnology. In this paper, we report the synthesis and characterization of nonlinear nanopores (such as curved and dendritic nanopores) containing alumina films. We show that control over the orientation of nanopores can be accomplished by controlling the geometric shape of aluminum substrates on which nanoporous alumina is grown. The anodically grown alumina on square and rectangular aluminum substrates showed cracks at the sharp edges of the substrates but no cracks were observed in nanoporous alumina films grown on cylindrical substrates. Our electrostatic calculations suggest that the electric field intensity at sharp edges of the rectangular/square substrates is significantly larger than that at the flat faces of the substrates. This leads to a faster alumina growth rate and hence increased stresses at these edges. We also.
Electrowinning of copper in a lab‐scale squirrel‐cage cell with anion membrane

This work describes the design and optimization of a laboratory-scale copper electrowinning cell based on reactive electrodialysis that incorporates a cathode made of copper granules contained in a rotating squirrel-cage-type enclosure. It also incorporates the Fe 2+ → Fe 3+ + e anodic reaction to overcome the principal disadvantages of conventional electrowinning technology. With this design, anolyte (aqueous FeSO 4 + H 2 SO 4 ) and catholyte (aqueous CuSO 4 + H 2 SO 4 ) are kept separate by an anion membrane that prevents cation transport between the electrolytes. Experiments were carried out to characterize cell performance under various conditions, and results show that energy requirements with this cell can be 25% lower than conventional industrial values. The same results also show that the squirrel-cage cell can be used to electrowin coppper from impoverished electrolytes.
Physics and chemistry of the Purcell alignment

Paramagnetic alignment of suprathermally rotating grains is discussed in view of recent progress in understanding subtle processes taking place over grain surface. It is shown that in typical ISM conditions, grains with surfaces of amorphous H$_{2}$O ice, defected silicate or polymeric carbonaceous material are likely to exhibit enhanced alignment, while those of aromatic carbonaceous material or graphite are not. The critical grain sizes and temperature for the Purcell's alignment are obtained and preferential alignment of large grains is established.
Graphene/TiO2 nanocomposites: synthesis, characterization and application in hydrogen evolution from water photocatalytic splitting

A series of titanium dioxide and graphene sheets (GSs) composites were synthesized with a sol–gel method using tetrabutyl titanate and graphite oxide (GO) as the starting materials. The obtained TiO2/GSs photocatalysts are characterized by X-ray diffraction, N2 adsorption analysis, Raman spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and ultraviolet-visible (UV-vis) diffuse reflectance spectroscopy. The photocatalytic activity of the as-prepared samples was evaluated by hydrogen evolution from water photo-splitting under UV-vis illumination. The influence of GSs content and calcinations atmosphere on the photocatalytic activity was also investigated. The results show that both GSs content and the calcinations atmosphere can affect the photocatalytic activity of the obtained composites.
L-cysteine encapsulation in liposomes: Effect of phospholipids nature on entrapment efficiency and stability

Liposomal entrapment of L-cysteine (L-CySH) could be a solution to enhance its oxidative stability and its intracellular bioavailability for glutathione (GSH) synthesis. This study addresses the influence of different factors (i.e. pH value (6.3 vs 7.4), antioxidant agents (EDTA or tocopherol (TO))) and nature of phosphatidylcholine (PC) (Soybean PC (SPC) vs hydrogenated SPC (HSPC)) to formulate and optimize Large Unilamellar Vesicles (LUVs) of L-CySH composed of PC/Cholesterol/Phosphatidylglycerol (6 : 3 : 1). pH decrease (p = 0.0002) and substitution of SPC by HSPC (p < 0.001) reduced L-CySH oxidation. EE% (entrapment efficiency) varied from 0.98% ± 0.54 (SPC, pH 7.4) to 6.46% ± 1.37 (HSPC, pH 6.3) and was improved by decreasing pH (p = 0.011) and using HSPC (p < 0.0001). An immediate release of L-CySH was observed with SPC. On the contrary, with HSPC at pH 6.3, 42.0% ± 1.2 and 73.0% ± 1.7 remained encapsulated after 24 h at 25°C and 4°C, respectively. In conclusion, HSPC offering both stronger rigidity and lesser propensity for peroxidation led to optimize L-CySH liposomal stability.