Miracle-dz/UniFAR-FTUs huggingface dataset:
Oxygen Delignification Chemistry and Its Impact on Pulp Fibers

Abstract Two southern pine kraft pulps with kappa numbers of 30.0 (SW1-0) and 48.0 (SW2-0) were oxygen delignified by 30–60% by varying the reaction temperature (78–110°C) and charge of sodium hydroxide (1.6–4.4%). O-bleachability was found to be correlated to the incoming kappa number and charge of sodium hydroxide employed. In general, a lower charge of caustic and a higher brownstock kappa number improved pulp bleachability. The residual lignin in the brownstocks and O-delignified kraft pulp samples was isolated and characterized by 13C and 31P NMR. 13C NMR analysis of the residual lignin samples indicated that the post-oxygen delignified pulps were enriched with α-carbonyl groups and carboxylic acid groups. The content of β-O-aryl structures was increased by 23–36% depending on the extent of oxygen delignification. The post-oxygen delignified pulps were also shown to have increased substituted aryl carbons. 31P NMR indicated that the relative content of condensed phenolic units increased by 9–20% after the oxygen delignification, depending on the severity of the O-stage. This observation was probably due to the accumulation or formation of 5,5-biphenyl structures in the process. The physical strength properties of brownstock and post-oxygen delignified pulps were assessed in terms of zero-span strength, tensile strength, tear strength, and burst strength. Oxygen delignification led to a slight increase in the curls and kinks of the pulp fibers. The O-stage was shown to cause a 4.8–15.6% decrease in zero-span strength. In contrast, oxygen delignification increased tensile strength. This result could be explained as the improvement of fiber bonding after the oxygen bleaching.
Ozone Wool ShrinkProofing Systems

Abstract Five new ozone, systems have been developed to make wool resistant to laundering shrinkage. Through rapid reaction, significant fiber degradation does not occur. Dyeing properties are improved and the fibers are somewhat bleached. In the most advantageous and energy-efficient process, steam is mixed with ozonea; garments, fabric, and sliver may be treated. Pilot or plant–scale treaters have been successfully tested for thrfee of the processes.
Electric double layer at the rutile (110) surface. 3. Inhomogeneous viscosity and diffusivity measurement by computer simulations

Molecular dynamics simulations were conducted to characterize the dynamic properties of the interface between aqueous electrolyte and the (110) surface of rutile (α-TiO2). For the first time, the inhomogeneous viscosity of water (at liquid density) in a slab formed by two rutile surfaces was determined computationally. The viscosity and diffusivity profiles show three different regions as a function of distance from the surface: (i) a region of two adsorbed layers of water molecules with apparently infinite viscosity and zero diffusivity, (ii) an interfacial inhomogeneous region consisting of additional 2−3 layers, and (iii) bulk-liquid behavior recovered as close as 15 A from the surface. The second layer of adsorbed water molecules becomes more loosely bound to the surface with increasing temperature up to 523 K. Our results supplement our previous structural findings and confirm that not only the structural but also the dynamic properties of the interface indicate that bulk properties are recovered wi.
Utilização de nitrogênio pelo trigo cultivado em solo fertilizado com adubo verde(Crotalaria juncea) e/ou uréia

The aim of this work was to evaluate the use of green manure nitrogen (Crotalaria juncea L.)-15N and urea-15N, in conjugated and separate fertilization. The experiment was carried out in pots with 5kg of a Rhodic Hapludox (sample collected in 0-20cm depth), using wheat (Triticum aestivum L.), cv. IAC-24. The completely randomized design was used with 5 treatments and 4 replicates: T1 - urea-15N (45mg kg-1 of N-urea); T2 - Crotalaria juncea-15N (100mg kg-1 of N-crotalaria); T3 - Crotalaria juncea-14N (100mg kg-1 of N-crotalaria) and urea-15N (45mg.kg-1 of N-urea); T4 - urea-14N (45mg.kg-1 of N-urea) and Crotalaria juncea-15N (100mg.kg-1 of N-crotalaria); T5 - treatment control (without source with N). The harvest of plants was realized 50 days after emergency (DAE), at flowering stage, separating the shoot of the root, being also sampled the soil of each pot. The parameter evaluated were the dry weight, height of plants, content of N and 15N abundance, being calculated the recovery of nitrogen from the sources. The N-urea recovery in wheat was larger, compared to N-crotalaria that stayed immobilized in the soil. In the soil-plant system, the N-crotalaria recovery was higher then N-urea. The soil fertilization with urea conjugated with crotalaria or applied separately resulted in larger dry weight and content of N in wheat. The use of Crotalaria juncea as green manure provided conservation of nitrogen, promoting larger recovery of the nutrient in the soil-plant system.
One-step metal-free construction of fluorescent 5-aryl-2,3-dicyanofurans from simple aryl ketones with DDQ

A variety of fluorescent 5-aryl-2,3-dicyanofurans were prepared by the treatment of electron-rich aryl ketones with DDQ. The presence of an alkoxy substituent on the benzene ring in the substrates was essential for an efficient cyclization to occur. This novel approach allows the metal-free construction of furan rings from simple aryl ketones.
WaterTransport in PEM Fuel Cells: Advanced Modeling, Material Selection, Testing and Design Optimization

Water management in Proton Exchange Membrane, PEM, Fuel Cells is challenging because of the inherent conflicts between the requirements for efficient low and high power operation. Particularly at low powers, adequate water must be supplied to sufficiently humidify the membrane or protons will not move through it adequately and resistance losses will decrease the cell efficiency. At high power density operation, more water is produced at the cathode than is necessary for membrane hydration. This excess water must be removed effectively or it will accumulate in the Gas Diffusion Layers, GDLs, between the gas channels and catalysts, blocking diffusion paths for reactants to reach the catalysts and potentially flooding the electrode. As power density of the cells is increased, the challenges arising from water management are expected to become more difficult to overcome simply due to the increased rate of liquid water generation relative to fuel cell volume. Thus, effectively addressing water management based issues is a key challenge in successful application of PEMFC systems. In this project, CFDRC and our partners used a combination of experimental characterization, controlled experimental studies of important processes governing how water moves through the fuel cell materials, and detailed models and simulations to improvemore » understanding of water management in operating hydrogen PEM fuel cells. The characterization studies provided key data that is used as inputs to all state-of-the-art models for commercially important GDL materials. Experimental studies and microscopic scale models of how water moves through the GDLs showed that the water follows preferential paths, not branching like a river, as it moves toward the surface of the material. Experimental studies and detailed models of water and airflow in fuel cells channels demonstrated that such models can be used as an effective design tool to reduce operating pressure drop in the channels and the associated costs and weight of blowers and pumps to force air and hydrogen gas through the fuel cell. Promising improvements to materials structure and surface treatments that can potentially aid in managing the distribution and removal of liquid water were developed; and improved steady-state and freeze-thaw performance was demonstrated for a fuel cell stack under the self-humidified operating conditions that are promising for stationary power generation with reduced operating costs. « less
Características químicas de amêndoas de barueiros (dipteryx alata vog.) de ocorrência natural no cerrado do estado de Goiás, Brasil

Aiming to broaden the knowledge about the nutritional content of baru fruits, a tree species from the Brazilian Savannah, in order to subsidize its economic management, it was determined the chemical characteristics of baru almonds from different geographical regions. In the state of Goias eleven sites were chosen for their abundance of baru trees, and at each site twelve trees in full production were randomly selected. Approximately sixty fruits were collected and, after selection, twenty fruits per tree were sampled. The almonds were extracted from the fruits and crushed, constituting a composite sample. Moisture content, protein, ether extract, minerals and fatty acid profiles were determined and submitted to analysis of variance and the means were compared by the Tukey test at 5% of probability. The almonds average moisture contents varied from 2.93 to 5.07g (100g)-1 from 25.16 to 27.69 (100g)-1 for proteins and from 32.42 to 37.36g (100)-1 for ether extract. The average content of saturated fatty acids varied from 19.93 to 25.74g (100 g)-1, and the unsaturated fatty acids varied from 73.47 to 79.19g (100g)-1. The most common fatty acids were oleic and linoleic, followed by palmitic, lignoceric, estearic, behenic gadoleic and araquitic. The most common mineral macronutrients were potassium, phosphorus and sulfur. Among the mineral micronutrients, iron had the highest concentration.
Momentum and Temperature‐Slip Coefficients with Arbitrary Accommodation at the Surface

Accurate theoretical expressions for momentum and temperature‐slip coefficients for monatomic gases with arbitrary accommodation at the surface are derived by applying a variational technique to the full linearized Boltzmann equation. In the jump regimes, the use of these expressions appears preferable to the use of the previous results based on mean‐free‐path theory or numerical methods. As an example, a correction in the reported values of accommodation coefficients is suggested.
A New Thermophoretic Precipitator for Collection of Nanometer-Sized Aerosol Particles

A new thermophoretic precipitator (TP) has been designed and used for the collection of nanosized aerosol particles. NaCl and Fe particles, with mean diameters of 55 nm and 3.6 nm, respectively, were used to determine the thermophoretic deposition efficiency as well as the uniformity of the deposition. When the average temperature gradients applied were 2200 K/cm and 2400 K/cm, a high thermophoretic deposition efficiency, close to 100%, was attained at aerosol flow rates below 15 sccm. A gradual decay in the efficiency was observed as the flow rate was increased. Theoretical calculations of particle deposition efficiency were in good agreement with experimental data. The deposition along the TP was shown to be homogenous on a millimeter scale for both NaCl and Fe particles collected on thin foil substrates and microscope grids, respectively. Finally, the thermophoretic precipitator was used to efficiently deposit Fe nanoparticles on a substrate for the subsequent growth of carbon nanotubes.
Fused Polycyclic Aromatics via Electrophile-Induced Cyclization Reactions: Application to the Synthesis of Graphite Ribbons

The study and subsequent development of conjugated organic polymers is an area which has provided enormous opportunities for researchers over the past several years. Recognized applications of these materials include their use in light-emitting diodes (LEDs), nonlinear optical (NLO) devices, lightweight batteries, and sensory devices. The growing number of uses and performance requirements for these materials is driving the need for ever more complex structures. A factor often limiting development of many structurally complex materials is synthetic methodology. In this report we describe the synthesis of one such structurally complex material, an all-carbon conjugated ladder polymer or graphite ribbon. 'J Critical to this synthesis was the development of a novel electrophile-induced cyclization reaction which provides a powerful new route to fused benzenoid aromatic hydrocarbon systems3 in high to quantitative yields. We chose to pursue an all-carbon framework as a result of the observation that conjugated polymers which display the highest conductivities have all-carbon backbones. Polyacetylene in particular has been reported to display conductivities as high as that of coppere4 However, due to its inherent instability, extensive development of polyacetylene has not been realized. An allcarbon conjugated system with an increa'sed degree of twodimensional structure, such as a ladder polymer, should maintain interesting electronic and optical properties while attaining increased stability relative to polyacetylene. Our approach was tosynthesize a single-strand p~ly@-phenylene)~,~ substituted with latent acetylenic functionality poised for postpolymerization chemistry. In the reaction's simplest form, the attack of an electrophile (E+) on a substituted 2-(ethyny1)biphenyl (Scheme 1) would provide a substituted phenanthrene. To explore this new cyclization reaction we chose to study the model compound 3 (Scheme 2) for characterization and optimization purposes. Compound 3 is readily synthesized by Pd catalyzed Suzuki cross-coupling of 2,5-dimethoxyphenylboronic acid with the aryl halide 2 in 96% isolated yield. Compound 1 is synthesized by chemoselective Pd(O)/Cu(I) coupling at the
Short-range-order spin clusters in one-dimensional Ising-like antiferromagnetic -filled PVA films: a study of physical properties

Polyvinylalcohol (PVA) films, filled with mass fractions % of , were prepared. The x-ray diffraction spectra indicated the partial crystallinity of PVA, which decays as w increases. The infrared analysis implied that the degree of syndiotacticity depends, nonmonotonically, on w. The observed peak at 520 nm, in the ultraviolet-visible spectra, revealed (i) the transition . (ii) the octahedral coordination of , (iii) the trapped electrons of the OH group of PVA and (iv) the spin-cluster excitation. The dependence on the temperature T of the dc electrical conduction was attributed to phonon-assisted interpolaron one-dimensional (1D) hopping of charge carriers. The temperature dependence of the dc magnetic susceptibility fits the 1D Ising antiferromagnetic equation well. The obtained electron spin resonance spectra exhibit the main features of the spectrum of the unfilled PVA. The dependence on the filling level of the logarithm of the calculated average rotational correlation frequency of mobile spins was compared with the corresponding dependences of the Ising coupling factor and the degree of syndiotacticity. The spin configuration of the present system was discussed in detail; it differs from the spin configuration of the -filled PVA films. The 1% -filled PVA film is the most suitable for its response to electromagnetic waves.
Quantitative phosphorus-31 NMR analysis of lignins, a new tool for the lignin chemist

Abstract A novel quantitative method has been developed for the determination of the various types of hydroxyl groups present in lignins. The syringyl, guaiacyl and p-hydroxyphenyl free phenolic groups, as well as the primary, and the secondary hydroxyl groups (belonging to individual erythro and threo forms of the aryl-glycerol β-O-4 ether strctures) can be quantitatively determined from a 31P NMR experiment. This is made possible by phosphitylating lignins with 1,3,2 dioxaphospholanyl chloride, followed by 31P NMR spectroscopy, in the presence of a relaxation reagent (chromium acetylacetonate) and an internal standard. The various aspects leading to the development of this technique are discussed together with relevant statistical information pertaining to the reproducibility and quantitative validity of the method. This simple and novel form of spectroscopy may become a valuable resource to the lignin chemist, because it can supply detailed quantitative information about the structure of a soluble lign.
Deposition of Monodisperse Insoluble Aerosol Particles in the 0.005 to 0.2 μm Size Range Within the Human Respiratory Tract

Abstract In 4 subjects with normal lung function total deposition of monodisperse, hydrophobic, uncharged silver particles in the 0.005 to 0.08 μm size range was investigated for a variety of breathing patterns during steady state mouth- and nose breathing. The evaluation of deposition was based upon measurements of mean particle number concentration in inspired and expired air by means of a condensation nucleus counter. Owing to the diffusional particle transport, total deposition increases with decreasing particle size and increasing mean residence time of the aerosol in the lungs. With decreasing particle size the time dependence becomes less and the effect of tidal volume more significant. A semi-empirical formula is derived which fits the experimental data.
Aster formation and rupture transition in semi-flexible fiber networks with mobile cross-linkers

Fibrous active network structures whose properties are regulated by motor proteins, or simply motors, are fundamental to life. Here, a full elastic and three dimensional model for such networks and motors is presented. The effects of surface anchoring are accounted for and we demonstrate that for unidirectional motors two basic contractile phases emerge in these systems. The transition is governed by a single parameter (τb/τc) which is the ratio of the breaking strain (τb) and the motility limiting strain (τc) of the motors. For τb/τc ≲ 2 and clamped boundaries, the network ruptures and formation of local asters occurs with a high density of motors at the centre and the fibers radially spanning out. This phase displays contraction strain during the formation of asters but the network stress is relaxed once the asters have emerged, demonstrating that the formation of aster-like structures provides a mechanism for stress relaxation. For 2.7 ≲ τb/τc the network remains intact, but reaches a force equilibrium with a high contraction strain in the case of clamped boundaries. Between these two limits the network is partly ruptured. Experimental measurements (e.g. J. T. Nishizaka, H. Miyata, H. Yoshikawa, S. Ishiwata and K. Kinosita Jr., Nature, 1995, 377, 251 and J. F. Finer, R. M. Simmons, J. A. Spudich, Nature, 1994, 368, 113) indicate that actin filament and myosin motors interact with τb/τc ≈ 2.7 which is right at the limit of motor induced fracture for a random network, indicating that e.g. a cytoskeleton with active myosin is susceptible to rupture. This is perhaps not a coincidence and may well be an important factor contributing to cellular dynamics. In the case of free boundaries the network collapses onto one single aster. We also show that the distribution of energy on the motors is a power-law, below the motility limit energy, with the exponent −0.5.
Laser nanostructuring of thin Au films for application in surface enhanced Raman spectroscopy

This paper presents experimental results of excimer laser nanomodification of thin gold films. Films with different thicknesses and deposition conditions are produced on SiO 2 substrate by pulsed laser deposition technique. Laser annealing of the deposited thin films results in its nanostructuring as the film is decomposed into nanoparticles with diameters in the range of few tens of nanometers. The produced nanostructured surfaces are covered with Rodamine 6G and tested as active substrates for Surface Enhanced Raman Spectroscopy (SERS). The SERS enhancement factor is estimated as high as 10 7 . The explanation of the results is made on the basis of the properties of the electromagnetic field in the near field zone of the nanostructured surface described by Finite Difference Time Domain (FDTD) simulation technique.
Estimation of Capsaicin Content of Two Varieties of Green Chilies by TLC Method

This study was aimed at finding out capsaicin content from two commonly used pungent varieties of green chilies in Tamilnadu, belonging to Capsicum frutescens namely, small variety (Capsicum annuum annuum ) used for cooking and an another variety used for making bajji (Capsicum annuum grossum) were estimated by TLC (Thin Layer Chromatography) method. Using varying doses of standard capsaicin calibration curve was obtained using regression analysis. The unknown concentration of capsaicin content in two varieties of chilies was found out from the standard curve by extrapolation method. The results were analysed by student t test. The capsaicin content in whole fruit and sees of small chili and bajji are not statistically significant (p > 0.05). This suggests that capsaicin content is almost equal in whole fruit and seeds of both the chilies. Whereas there is significant difference between the two chilies in capsaicin content of pericarp (p < 0.05) suggesting that Capsicum.annuum annuum is having more capsaicin concentration than Capsicum.annuum grossum.
A K-model for simulating the dispersion of sulfur dioxide in a tropical area

Abstract A K-model for describing the dispersion of SO2 released into the atmosphere from the source is studied. The numerical approximation using 3-D fractional step method is applied based on discretization of the time dependent atmospheric advection-diffusion equation. The diffusion coefficients are supplied by the meteorological station. The initial condition is taken to be zero concentration of pollutant everywhere. The flux of pollutant is assumed to be zero at the ground and at the inversion layer. The concentration of pollutant at the source is assumed to be a δ-function, which gives rise to a steady emission rate Q of pollutant. The resulting model is solved for the test problem with the range of parameters in the Pasquill’s stability classes A (Pasquill (1974)) (see [3]).
A nitrogen-doped ordered mesoporous carbon nanofiber array for supercapacitors

A nitrogen-doped ordered mesoporous carbon nanofiber array was prepared by a combination of a hard-templating and a soft-templating method. The obtained N-enriched carbon material has a high surface area (1030 m2 g−1) and a large pore volume (2.35 cm3 g−1), with uniform mesopores located at 15.0 nm. The material with a nitrogen content of 6.7 wt% shows a high capacitance of 264 F g−1 in 1.0 M H2SO4 electrolyte and a good rate capability with a capacitance retention of 86% at 10 A g−1vs. 0.5 A g−1. It also delivers an excellent cycling stability without capacitance fading over 10000 cycles.
Thermal transport properties of thin films of small molecule organic semiconductors

A series of harmonic Joule-heating experiments have been employed to determine the thermal conductivities of thin films of pentacene, N,N′-diphenyl−N,N′-di(3-methylphenyl)−(1,1′-biphenyl)-4,4′-diamine, and tris(8-hydroquinolinato)aluminum, three widely used organic semiconductors. Room-temperature thermal conductivity values of 0.51, 0.24, and 0.48W∕mK were measured for films of these three compounds, respectively. These values are over two orders of magnitude lower than those of inorganic semiconductors. While amorphous films were found to display only small thermal conductivity changes over the temperature range of 228–350 K, pentacene exhibited stronger variations that are typical of phonon-phonon scattering observed in polycrystalline semiconductors.