Miracle-dz/UniFAR-FTUs huggingface dataset:
Speciation of Cr(III) and Cr(VI) in Environmental Samples after Solid Phase Extraction on Amberlite XAD–2000

A method for speciation of Cr(III) and Cr(VI) in real samples has been developed. Cr(VI) has been separated from Cr(III) and preconcentrated as its pyrrolidinedithiocarbamate (APDC) complex by using a column containing Amberlite XAD-2000 resin and determined by FAAS. Total chromium has also been determined by FAAS after conversion of Cr(III) to Cr(VI) by oxidation with KMnO4. Cr(III) has been calculated by subtracting Cr(VI) from the total. The effect of pH, flow-rate, adsorption and batch capacity andeffectofvariousmetalcationsandsaltanionsonthesorptionontotheresinwereinvestigated.TheadsorptionisquantitativeinthepHrangeof1. 5-2.5,andCr(VI)ionwasdesorbedbyusingH2SO4inacetone. The recovery of Cr(VI) was 97 4 at a 95% confidence level. The highest preconcentration factor was 80 for a 200 mL sample volume. The adsorption and batch capacity of sorbent were 7.4 and 8.0 mg g –1 Cr(VI),respectively,andloadinghalftimewas5.0min. ThedetectionlimitofCr(VI)is0.6g/L.Theprocedure has been applied to the determination and speciation of chromium in stream water, tap water, mineral spring water and spring water. Also, the proposed method was applied to total chromium preconcentration in microwave digested moss and rock samples with satisfactory results. The developed method was validated with CRM-TMDW-500 (Certified Reference Material Trace Metals in Drinking Water) and BCR-CRM 144R s (Certified Reference Material Sewage Sludge, Domestic Origin) and the results obtainedwereingoodagreementwiththecertifiedvalues.Therelativestandarddeviationswerebelow6%.
Effect of Sodium Borohydride on Populus tremula L. Kraft Pulping

Sodium borohydride (NaBH4) added kraft pulping was performed using European aspen (Populus tremula L.) chips and the effects of the NaBH4 addition on the physical and optical properties of pulps and resultant papers were investigated. In order to determine the optimum cooking parameters, 6 different laboratory experiments were carried out, which indicated that 2 cooking conditions were better than the others. The effects of 1%, 2%, and 3% NaBH4 additions on pulps and paper properties were investigated based on these 2 cooking conditions. It was noted that the increasing level of NaBH4 added improved the screened pulp yield and pulp viscosity levels and reduced the Kappa number. There was no statistical significance regarding the strength properties of kraft-NaBH4 pulps compared to control pulps at 50 ± 3 °SR freeness level. However, the brightness of handsheets was increased by NaBH4 additions.
Carbon Nanotube Reinforced Titanium Metal Matrix Composites Prepared by Powder Metallurgy—A Review

Titanium-based metal composites (TMCs) are showing great potential to replace existing traditional materials in aerospace, automotive, and other high temperature engineering applications. This is due to their excellent mechanical, thermal, and physical properties and improved strength to weight ratio. Weight savings in the aerospace industry results in higher efficiency. Carbon nanotubes (CNTs), because of their low density and high Young's modulus, are considered to be an excellent reinforcement for metal matrix composites (MMCs). In the last 20 years extensive research has been carried out to investigate the combination of carbon nanotubes with aluminum, nickel, copper, magnesium, and other metal matrices. The production techniques such as mechanical alloying through powder metallurgy routes and their effects on the mechanical properties of CNT reinforced TMCs are reviewed in this article. The role of the volume fraction of carbon nanotubes and their dispersion into the metal matrix are highlighted. Governing equations to predict the mechanical and tribological properties of CNT reinforced titanium matrix composites are deduced. With the help of this initial prediction of properties, the optimal processing parameters can be optimized. Successful development of CNT reinforced TMCs would result in better wear and mechanical behavior and enhance their ability to withstand high temperature and structural loading environments.
Transient simulation of the combustion of fuel-lean hydrogen/air mixtures in platinum-coated channels

The start-up of platinum-coated, hydrogen-fuelled planar channels with heights of 1 mm is investigated numerically using 2-D transient simulations with detailed hetero-/homogeneous chemistry, heat conduction in the solid wall and surface radiation heat transfer. Simulations encompass pressures of 1 and 5 bar and fuel-lean H2/air equivalence ratios of 0.10 to 0.28. Catalytic ignition is inhibited by rising pressure and increasing hydrogen concentration. However, at temperatures above the catalytic ignition temperature Tign, the dependencies of the heterogeneous reactivity reverse, showing a positive order ∼1.5 with respect to hydrogen concentration and an overall positive pressure order of ∼0.97. Despite the longer catalytic ignition times for the larger equivalence ratios, the times required to reach steady state are shorter at larger stoichiometries due to their enhanced catalytic reactivity at T > Tign and the resulting higher exothermicity. Following catalytic ignition, the wall temperatures eventually attain superadiabatic values due to the diffusional imbalance of hydrogen. Homogeneous chemistry considerably moderates the superadiabatic surface temperatures at 5 bar, as the gaseous combustion zone extends parallel to the channel wall and thus shields the catalyst surface from the hydrogen-rich channel core. Furthermore, gas-phase chemistry reduces the steady-state times and substantially increases the hydrogen conversion.
Electrochemistry of Molecule-like Au 25 Nanoclusters Protected by Hexanethiolate

Near-monodisperse fractions of hexanethiol-protected gold nanoclusters (Au(25) and Au(144)) have been obtained by using a variation of the two-phase Brust method based on constant low temperature (4 °C) and control of the stirring conditions during the synthesis procedure. The size and dispersity of the Au25(SC6)18 and Au144(SC6)59 nanoclusters are determined by electrochemical means. The two first oxidation steps for the molecule-like Au25(SC6)18 clusters are quasi-reversible, and the electron transfer rate constants and diffusion coefficients have been determined by cyclic voltammetry and electrochemical impedance spectroscopy. The electrochemical behavior of these nanoclusters in different solvents can be explained by using the model described by Girault et al. (J. Phys. Chem. B 2006, 110, 21460; 2005, 109, 23925.) that considers the contribution of the bulk solvent relative permittivity on the charging energy values. Electrolyte ions and solvent molecule penetration must be taken into account to expla.
Non-Equilibrium Molecular Dynamics for Simulating Permeation of Gas Mixtures through Nanoporous Carbon Membranes

This paper deals with the computer modeling of permeation of a gas mixture through a nanoporous membrane by introducing a novel approach of non-equilibrium molecular dynamics (NEMD). A combination of the grand canonical ensemble (GCE or μVT) Monte Carlo (MC) technique and the boundary-driven NEMD method (Hafskjold et al., 1993; Ikeshoji and Hafskjold, 1994) is proposed for simulation of gas permeation based on the selective adsorption and surface diffusion mechanism
Simulation of Fluid Flow Through a Granular Bed

Numerical study of flow through random packing of non-overlapping spheres in a cylindrical geometry is investigated. Dimensionless pressure drop has been studied for a fluid through the porous media at moderate Reynolds numbers (based on pore permeability and interstitial fluid velocity), and numerical solution of Navier-Stokes equations in three dimensional porous packed bed illustrated in excellent agreement with those reported by Macdonald [1979] in the range of Reynolds number studied. The results compare to the previous work (Soleymani et al., 2002) show more accurate conclusion because the problem of channeling in a duct geometry. By injection of solute into the system, the dispersivity over a wide range of flow rate has been investigated. It is shown that the lateral fluid dispersion coefficients can be calculated by comparing the concentration profiles of solute obtained by numerical simulations and those derived analytically by solving the macroscopic dispersion equation for the present geometry.Copyright © 2006 by ASME
Negative Magnetoresistance and Magnetic Susceptibility of Boronated Graphite

Abstract Boronated graphite specimens were prepared from a grafoil heat-treated at 3000°C for 30 min. The transport properties, such as the electrical resistivity, Hall coefficient and transverse magnetoresistance, and the total magnetic susceptibility were measured for the pristine and boronated specimens. For the specimen with high boron concentration, a negative transverse magnetoresistance at liquid nitrogen temperature and weakly temperature-dependent resistivity were observed. Assuming that the negative magnetoresistance is due to a three-dimensional weak localization, a calculation was carried out for the temperature dependence of the resistivity and transverse magnetoresistance at low temperatures in terms of Slonczewski-Weiss-McClure band model and a weak localization theory obtained by extending Kawabata's theory. The experimental finding agreed well with that the calculation predicted.
Fate of Plant Available Nutrients during Hydrothermal Carbonization of Digestate

Products from the hydrothermal carbonization of two digestates have been analyzed in order to investigate the fate of nitrogen, phosphorus, and potassium in specific plant available speciations. The availability of phosphate and potassium ions was significantly increased due to hydrothermal carbonization of a nutrient-rich digestate. In contrast, the availability of NH4+ and PO43− in the process liquor was decreased to < 10 % of the original value in the case of a nutrient-poor digestate. With the exception of nitrate, process parameters did not show an influence on the recovery of the investigated ions with the HTC process liquor.
Sodium 3‐ammonio‐1‐hydroxy­propyl­idene‐1,1‐bisphospho­nate monohydrate

The title compound, sodium pamidronate monohydrate, Na+·C3H10NO7P{}_{2}^{\,- }·H2O, crystallizes in sheets in the ab plane through Na—O coordination and hydrogen bonding to the pamidronate zwitterion. The neutral sheets are connected through hydrogen bonding, including the water molecule in the c direction.
Reliable determination of the few-layer graphene oxide thickness using Raman spectroscopy

We report on a reference-free Raman spectroscopy method for a precise thickness determination of the multilayered graphene oxide flakes. The method is based on the normalization of the total integral intensity of D and G Raman bands to the integral intensity of the second-order optical phonon peak of the silicon substrate in the Raman spectrum. The normalization provides discrete ratio values corresponding to the number of graphene oxide layers in the respective flakes with the intensity linearly increasing with the number of layers. This provides a fast and robust determination of the thickness of graphene oxide flakes in terms of the layer number up to high values. A comparison with conventional spectrally resolved reflectivity mapping shows similar sensitivity, while selectivity to particular functional chemical groups is a bonus of the Raman-based method. Copyright © 2015 John Wiley & Sons, Ltd.
Models of Sorptive Toxic Substances in Freshwater Systems. III: Streams and Rivers

Equations defining the steady‐state distributions of solids and sorptive substances in freshwater streams and rivers are developed and solved analytically. The spatial variations of the flow and suspended solids are incorporated in the chemical equations, which take into account the kinetic and transfer routes of the dissolved and particulate components. The sorptive interaction between these components is characterized by instantaneous equilibrium. The solution for the total concentration of the chemical from which the dissolved and particulate components follow, is developed. Various relationships between the partition coefficient and the solids are incorporated into the equations. The exchange of both the dissolved and particulate components of the chemical between the water column and the bed is a key factor. The calculated spatial profiles of heavy metals and organic chemicals are compared to observed data under different flow and wastewater discharge conditions in freshwater rivers.
HIGH FERTILIZER RATES INCREASE SUSCEPTIBILITY OF TEA TO WATER STRESS

A study to determine the association of fertilizer with soil water deficit in tea [Camellia sinensis (L.) O. Kuntze] was conducted in a rain-out shelter using potted plants, in which five rates of fertilizer (0, 75, 150, 225 and 300 kg Nitrogen ha−1) and six levels of soil water content (38, 34, 30, 26, 22 and 18% v/v) were applied in a complete randomized design and replicated three times. The soil water treatment was maintained for a period of 12 weeks during which shoot growth, plant water relations, and dry matter partitioning in tea were determined. A parallel field experiment with the above fertilizer rates was conducted at three sites in which shoot density and shoot weight were determined during the dry season. Fertilizer improved leaf-to-root and leaf-to-total mass ratios (P < 0.001), reduced shoot growth, shoot water potential and specific leaf area (P < 0.001). The fertilizer exacerbated drought effect on tea through disproportionate assimilate partitioning which consequently weakened the ability of tea to tolerate water stress. Results suggest an indirect contribution of fertilizer supply to drought susceptibility in tea.
Lubricity of Ethanol-Biodiesel-Diesel Fuel Blends

Blending bioethanol with diesel fuels is an alternative to incorporate a renewable fraction in vehicle fuels which is receiving growing attention for its economic and environmental advantages. The generalized practice in Europe of including some biodiesel content in the commercial diesel fuel has even enhanced the interest of the ethanol blends as a consequence of the wider range of stability when biodiesel is added. However, one of the main concerns is related to the loss of lubricity caused by the presence of ethanol. First, this work reviews the previous experiences studying the effect of renewable components on the diesel fuel lubricity. Second, an experimental work, carried out in a high frequency reciprocating rig at different temperatures, is presented trying to distinguish the nonlinear contributions of ethanol, biodiesel, and petroleum diesel fuel to the lubricity of three series of blends (one composed of binary ethanol-diesel blends and two more composed by different ternary blends). The incorp.
Refinement of the Crystal Structure of Synthetic Chervetite, Pb2V2O7

The structure of synthetic chervetite has been refined by full matrix least-squares to a ωR = 0.029 using 1105 reflections. Unit cell dimensions are a = 13.3689(7), b = 7.1607(4), c = 7.1027(4) A, β = 105935(5)°, and the space group is P21/a. The structure, originally solved by Kawahara, is a dichromate-type structure with a V2O74− group eclipsed to within 11 ± 5°. The Pb2+ ions are irregularly coordinated to 8 or 9 oxygens with distances from 2.40 to 3.20 A. The distortion of the Pb–O distances is considerably greater than the corresponding distortions of the Sr–O distances in the similar β-Sr2V2O7 structure and is related to the tendency of Pb2+ to form directional covalent bonds. The V–O distances range from 1,665 to 1.720 A for terminal oxygens and are 1.812 and 1.821 A for the bridging oxygens. The V–O distances are consistent with the strengths of the Pb—O bonds.
Development and evaluation of transdermal patches of aceclofenac

The aim of this study was to develop and evaluate matrix-type transdermal therapeutic system containing aceclofenac with different ratios of hydrophilic polymers (hydroxylpropyl methylcellulose, sodium carboxy methylcellulose) and a hydrophobic polymer (ethyl cellulose). Thirteen aceclofenac transdermal patch formulations consisting of hydroxyl propyl methyl cellulose, ethyl cellulose and sodium carboxy methyl cellulose polymeric combinations were prepared by solvent casting. These prepared transdermal patches were evaluated for in vitro release, weight variation, moisture content, folding endurance, thickness, drug content and swelling studies. The diffusion studies were performed by using modified Franz diffusion cell. The formulation, F10 showed the maximum release of 98.18 % in 4 h, where as F2 showed the maximum release of 93.22 % in 8 h. Formulation, F9 showed the minimum release of 41.4 % in 8 h. Hence F2 (ethylcellulose: hydroxylpropyl methylcellulose ratio 3:2), exhibited good physicochemical properties, zero order in-vitro drug release and flux was selected as the best among all for transdermal drug delivery. So it can be reasonably concluded that aceclofenac can be formulated into the transdermal matrix type patches to sustain its release characteristics.
New variations on the soap film experiments of Plateau I. Experiments under forced drainage

Abstract We have explared a variation of Plateau‘s wire experiment, in which soap solution is continually added at the top of a wire frame, resulting in the displacement, distortion and eventual instability of the equilibrium configuration of soap films. In the case of a cubic frame, an eightfold vertex of Platearr borders (corresponding to a twelvefold intersection of films) can be created in this way. We also observed the passage of a 'triple bubble’ along a Plateau border when a single drop is introduced at the Plateau border junction.
Interfacial gaseous states on crystalline surfaces

We previously reported formation of spherical-cap-shaped nanobubbles and a quasi-two-dimensional gas layer (micropancakes) on highly oriented pyrolytic graphite (HOPG) surfaces by the solvent-exchange protocol. Here we report that the same protocol is capable of inducing gaseous micropancakes as well as nanobubbles on two other crystalline surfaces: molybdenum disulfide (MoS2) and talc in water. The maximum height of gaseous micropancakes in atomic force microscopy (AFM) images was found to correlate well with the maximum height of nanobubbles on the same surface. In contrast, the same protocol was unable to induce spherical-cap-shaped nanobubbles or gaseous micropancakes on amorphous (glassy) carbon or on trimethylchlorosilane-coated silicon surfaces, which had a similar contact angle of water as the crystalline surfaces. It appears that formation of these interfacial gaseous states requires the presence of adequate nucleation sites on the surfaces (in addition to local supersaturation of gases created during the solvent exchange). The layered structure of the surfaces and concomitant presence of atomic steps appeared to have facilitated the formation of gaseous micropancakes.
Determination of manganese in seawater using flow injection analysis with on-line preconcentration and spectrophotometric detection

A highly sensitive method for the rapid determination of dissolved Mn(II) and total dissolvable Mn in seawater has been developed. The method uses on-line concentraion of Mn(II) onto 8-hydroxyquinoline immobilized onto a vinyl polymer gel. The Mn(II) is then eluted from the gel by acid and its concentration determined by spectrophotometric detection of the malachite green formed from the reaction of leucomalachite green and potassium periodate with Mn(II) acting as a catalyst
Pressure retarded osmosis in closed circuit: a new technology for clean power generation without need of energy recovery

AbstractPower generation from salinity gradients by means of Pressure Retarded Osmosis (PRO) is currently preformed by conventional methods, wherein Energy Recovery (ER) is an essential feature without which such a process is impossible. The newly conceived Closed Circuit (CC) Pressure Retarded Osmosis technology (CC-PRO) described herein is based on a continuous consecutive sequential batch process; wherein, pressurized high salinity feed (HSF) is continuously supplied to the inlets of PRO modules and pressurized effluent removed from their outlets through internal circulation means by the alternating engagement/disengagement of two side conduits (SC). This process proceeds with high energy conservation without need of ER means. The new CC-PRO technology enables high operational flexibility achieved by set point selection of the permeation flux; the circulation flow; the applied pressure of power generation; and the flow ratio circulation/permeation which defines the salinity and osmotic pressure gradien.
Volume of mixing, speed of sound, and viscosity of methyl cellosolve with aliphatic alcohols at 308.15 K

The volume of mixing, speed of sound, and viscosity of binary liquid mixtures composed of methyl cellosolve (1) and aliphatic alcohols (2), namely, methanol, propan-1-ol, butan-1-ol, 2-methyl-propan-1-ol, 2-methylpropan-2-ol, and pentan-1-ol are measured at 308.15 K. The results are used to derive densities and isentropic compressibilities. The excess volumes and deviations in compressibility and viscosity are discussed in terms of molecular interaction between like and unlike components
Réponse des auteurs et erratum dans Ann. Toxicol. Anal. 2005 ; 17 : 43-55

Les auteurs remercient Ph. Saviuc pour l’interet porte a leur article (1) et la pertinence de ses remarques. Cependant, ils tiennent a apporter quelques precisions : Comme Ph. Saviuc l’a remarque, la quantite de muscarine dans le chapeau d’A. muscaria que nous avons analyse, est elevee. Elle atteint 0,2 %, alors que la litterature parle de quantites de l’ordre de 0,002 %. Ce point n’avait pas ete discute car il sortait des notions developpees dans l’article centre sur l’interet de la LCMS/MS pour l’analyse des toxiques vegetaux en general. Nous tenons a preciser que l’analyse ete realisee sur une tres petite quantite d’echantillon (100 mg), la concentration mesuree n’est donc probablement pas representative de celle de l’ensemble du champignon ; on peut remarquer que le taux de muscarine que nous avons dosee dans le pied est d’environ 0,004 %. Des analyses plus precises quant a la localisation des prises d’essai doivent etre entreprises mais une amelioration chromatographique utilisant un autre type de colonne doit etre prealablement realisee. Quoiqu’il en soit les faibles prises d’essai necessaires grâce a cette technique devraient nous permettre une localisation interessante de la muscarine dans ces champignons. Les principales toxines d’ A. muscaria (le muscimol, l’acide ibotenique et la muscazone) ont ete decrites dans notre article comme des agonistes du GABA. Cette information est tiree de l’ouvrage de reference de Bruneton (2). Le role de la muscazone n’est effectivement pas clairement etabli mais selon Michelot et coll. (3) elle aurait une action pharmacologique mineure par rapport a l’acide ibotenique et au muscimol. Cependant, bien que les effets propres de ces deux dernieres toxines ne soient pas bien compris, il est etabli que l’acide ibotenique se decarboxyle partiellement en muscimol, spontanement, par chauffage ou lors de la digestion. Or les consommateurs temoignent que les effets adverses non recherches diminuent en pelant les champignons, en jetant l’eau ou ils ont bouilli, ou encore en les deshydratant par chauffage. L’effet recherche par les consommateurs semble donc etre celui majori-