Miracle-dz/UniFAR-FTUs huggingface dataset:
Thermodynamics of solutions of polyelectrolytes, ionic surfactants and other charged colloidal systems

Thermodynamic arguments are used to derive a simple expression for the Donnan equilibrium between a solution of charged colloid plus electrolyte and a solution of electrolyte alone. From it, expressions for the solute chemical potentials and the osmotic pressure are obtained. Polydispersity, excluded volume effects and interactions between the various solute species are allowed for. The treatment has features in common with approaches based on the Poisson–Boltzmann equation but is simpler and is not restricted by considerations of particle geometry. It predicts successfully the characteristic behaviour of dilute solutions of polyelectrolyte plus salt and agrees with experimentally obtained activity coefficients of supporting electrolyte better than a prominent existing model. When the theory is applied to solutions of ionic surfactants the dubious assumptions inherent in some previous approaches are avoided, yet similar equations emerge which allow better for solution non-ideality and give good agreement with experiment. The treatment also permits the application to charged micelles of the methods successfully applied previously to non-ionic micelles. The application to colloid stability is discussed. Finally, the application to polyacid titration behaviour is outlined. This exposes some limitations of the theory and suggests appropriate modifications.
On the role of symmetry in the ab initio hartree‐fock linear‐combination‐of‐atomic‐orbitals treatment of periodic systems

The symmetry properties of the mono- and bielectronic terms contributing to the Fock matrix in the ab initio Hartree–Fock treatment of periodic systems are discussed. A computational scheme which takes full advantage of the point symmetry is presented; in this respect, it represents a generalization of the scheme proposed in Int. J. Quantum Chem. 17, 501 (1980). Computational details and numerical examples are reported; it is shown that with respect to two of the bottlenecks of this kind of calculation, namely, computer time and backing storage required for the bielectronic integrals, it is possible to obtain saving factors as large as h and h2, respectively, where h is the order of the point group. Preliminary tests are reported which indicate that the study of relatively complicated systems, like quartz or corundum (9 and 10 atoms in the unit cell, respectively) at an ab initio Hartree–Fock level is now within reach.
Controllable formation of aromatic nanoparticles in a three-dimensional hydrodynamic flow focusing microfluidic device

Herein we investigate the formation of aromatic organic nanoparticles in a three-dimensional (3D) hydrodynamic flow focusing microfluidic device. We demonstrate a microfluidic based solvent/non-solvent exchange technique that enables controllable formation of aromatic nanoparticles with tunable size and size distribution. The 3D focusing is achieved by hydrodynamically focusing the sample stream with sheathed streams in both horizontal and vertical directions, and solvent/non-solvent exchange happens between the solvent contained sample stream and non-solvent contained horizontally sheathed streams. The 3D focusing effect was visualized using florescence confocal microscopy and the dynamics of solvent (DMF) depletion in the focused stream was calculated using a finite element computation software package COMSOL Multiphysics. By analyzing the results of self-assembled aromatic nanoparticles in the microfluidic device, we find that the speed of DMF depletion strongly influences the size and size distribution of self-assembled aromatic nanoparticles, and a rapid depletion of DMF is critical for achieving small aromatic nanoparticles with narrow size distribution. This work suggests that our 3D hydrodynamic flow focusing microfluidic device with the ability to precisely control the convective-diffusion process, and continuously vary the fluid flow conditions is promising for studying the formation of nanomaterials.
Heavy metals in marine sediment phases determined by sequential chemical extraction and their interaction with interstitial water

Abstract A sediment core obtained in a highly polluted area of the Baie de Villefranche (Mediterranean Sea, France) was analysed for Fe, Mn, Cu, Cd, Co, Pb, Cr, Ni and Zn using EDX‐RF (interstitial water) and AAS (sediment extracts). Characterization of the chemical forms of the metals in the solid phase was carried out using chemical extraction techniques, and the vertical distribution of solutes in the interstitial water was interpreted in relation to the total amounts of the respective components in the solid phases.
Powder Deposition in Three Parallel-Oriented Dies of Different Shapes

Uniformity of bulk density distribution during the die filling process is required to minimize quality problems, such as distortion and cracking, for powder compacts. Understanding the die filling process is necessary in ensuring a uniform powder deposition. The second-generation pressure deposition tester (PDT-II) was used to investigate the deposition process and final pressure distribution of powder filling in toroidal, cylindrical, and E-shaped dies. All tests were conducted using a spray-dried free-flowing granular powder. The results indicated that for toroidal dies: (1) the area around 0° orientation (the leeward end) had the highest pressure values (1186.7 to 2498.0 Pa), with the average pressure values of the remaining area 353.7–648.0 Pa; (2) the pressure distribution was symmetrical about the centerline parallel to the feed shoe movement direction; (3) the highest feed shoe speed (500 mm/s) led to the most nonuniform pressure distribution among the three speeds; (4) higher feed shoe speed did not always result in higher final pressure values; and (5) the right die tended to have higher final pressure values (215.0 to 2498.0 Pa) than the center die (95.4 to 2052.5 Pa). For E-shaped dies: (1) the final pressure values of the middle leg (308.9 to 760.7 Pa) were higher than those of the left and the right legs (148.9 to 530.3 Pa); (2) the area along the backside had the highest final pressure value (1054.6 to 1303.8 Pa); (3) the pressure distribution was symmetrical about the centerline parallel to the feed shoe movement direction; and (4) neither the center die nor the right die always had higher pressure values than the other one at all locations. Comparison between cylindrical and toroidal dies indicated that: (1) neither of the two die shapes (cylinder and toroid) led to consistently higher or lower final pressure values at all locations and (2) for all three feed shoe speeds, the toroidal die had higher average final pressure values in the 0° orientation.
Mercury pollution on district of Dimembe river system North Sulawesi, Indonesia, due to traditional gold mining activities

Mercury contamination caused by the amalgamation of gold in small scale gold mining is a environmental problem. Small-scale gold mining (SSGM) is common in mineral-endowed developing countries. It offers an important means of livehood and has served as a safety net in times of natural calamities or economic distress. In north Sulawesi Province alone, approximately 22000 small-scale gold miners were active in 1998, and produced an estimated 10 tonnes of gold bullion. Activities of traditional/illegal gold mining (PETI) in Dimembe of district, which is located in Minahasa Regency, North Sulawesi Province. The major environmental concern associated with PETI in mercury pollution from processing of gold-bearing ore. In both the inorganic and organic forms, mercury is one of the most toxic substances to humans. One of the environmental pollution is water pollution on district of Dimembe river system that is probably caused by the use of mercury (Hg) in processing mine ore. This mercury is used in an iron rolling vessel, which is called tromol. Mercury concentration employed in this operation reaches 1 kg out of 30 kg ore. Sampling stage was conducted at Warat river, downstream Talawaan river, Merut river and Kadumut river on late April 2002 by BAPEDALDA team together with Health Laboratory staff. Material which were sampled was water. Sampling methods carried out were bottle sample immersed about 10 cm below the water surface. The analysis method used was mercury analyzer. The analysis result show that total concentration of mercury range from 1.69 to 25 54 ppb. This concentration is closed to Water Quality Standard IV Class that is 0.005 mg/L (Regulation Government No 82/2001). The result of this research indicate that the district of Dimembe river system in the gold mining area have been contaminated by mercury.
Effect of cation doping on mechanical properties of yttria prepared by an optimized two-step sintering process

Undoped Y2O3 and Y2O3 doped with either Si4+, Er3+, Yb3+, Al3+ or Ti4+ were fabricated by a two-step sintering method. The concentration of each dopant cation (Si4+, Er3+, Yb3+, Al3+, and Ti4+) was adjusted so that the dopant:yttria molar ratio was 0.01 and the mechanical properties and the microstructures of each were characterized. The Vickers hardness and the bending strength of cation-doped Y2O3 increased in the order Si4+, Er3+, Yb3+, Al3+, and Ti4+ paralleling increases in the relative density. Ti-doped-Y2O3 had the highest density and the highest strength. Transmission electron microscopy analysis revealed that Ti segregated to the grain boundaries of Y2O3. The two-step sintering method was optimized to enhance the mechanical properties of Y2O3. As a consequence, Ti-doped Y2O3 with the Ti4+:yttria molar ratio of 0.01 sintered at the optimized heating schedule was found to have a Vickers hardness and three-point bending strength as high as 874 Hv and 307.0 MPa, respectively.
Chemical Constituents Isolated from Andrographis paniculata

Phytochemical investigation of the aerial parts of Andrographis paniculata give diterpenic constituents andrographolide, 14-deoxy-11,12-didehydroandrographolide, 14-deoxyandrographolide, 3,14-dideoxyandrographolide, 14-deoxy-11-oxoandrographolide, 14-deoxy-12-hydroxyandrographolide, neoandrographolide, andrographiside and 14-dcoxyandrographiside. The structures of these compounds have been established on the basis of spectral data analysis.
Effect of button mushroom compost on mobilization of heavy metals by sunflower

The potential ability of Button mushroom compost (BMC) to solubilize heavy metals was estimated with metal contaminated soils collected from abandoned mines of Boryeong area in South Korea. The bacterial strains in BMC were isolated for investigating the mobilization of metals in soil or plant by the strains and identified according to 16S rRNA gene sequence analysis. When metal solubilization potential of BMC was assessed in a batch experiment, the BMC was found to be capable of solubilizing metals in the presence of metals (Co, Pb and Zn) and the results showed that inoculation of BMC could increase the concentrations of water soluble Co, Pb and Cd by 35, 25 and 45% respectively, than those of non-inoculated soils. BMC-assisted growth promotion and metal uptake in sunflower (Helianthus annuus) was also evaluated in a pot experiment. In comparison with non-inoculated seedlings, the inoculation led to increase the growth of H. annuus by 27, 25 and 28% respectively in Co, Pb and Zn contaminated soils. Moreover, enhanced accumulation of Co, Pb and Zn in the shoot and root systems was observed in inoculated plants, where metal translocation from root to the above-ground tissues was also found to be enhanced by the BMC. The apparent results suggested that the BMC could effectively be employed in enhancing phytoextraction of Co, Pb and Zn from contaminated soils.
Local Solvation Shell Measurement in Water Using a Carbon Nanotube Probe

Combining a carbon nanotube probe and a highly sensitive dynamic measurement scheme has enabled us to use atomic force microscopy to measure oscillatory forces in water on approaching a surface that has been laterally characterized on a nanometer scale. This opens up the possibility of investigating water layers under a variety of experimental conditions and as a function of precise lateral position on any surface including biological membranes and macromolecules. Among the many and varied roles of water layers are effects on biomolecular adhesion, colloid dispersion, and tribology, which can now be investigated with nanometer lateral resolution and with a wider range of materials than that previously provided by surface forces appartus.
Root‐Derived Carbon and the Formation and Stabilization of Aggregates

It is hypothesized that particulate organic matter (POM) contributes to aggregate stability. However, little is known about the dynamics of the POM fraction or its role in aggregate formation. A simulated no-till study was conducted to examine changes in free and aggregate-associated POM during the decomposition of in situ 14 C-labeled roots during a 1-yr incubation in a loess-derived silt loam. Two water pretreatments (capillary-wetted and slaked) were applied to soil samples collected during the incubation, and the samples were then wet sieved to obtain five aggregate size fractions. Densiometric separations were used to isolate free and released POM (frPOM) and intraaggregate POM (iPOM). Small macroaggregates (250-2000 μm) were enriched in iPOM- 14 C on Day 0 which suggested that many of these aggregates formed around cores of new, root-derived POM during the growth and senescence of the oat plants. Slaking resulted in the disruption of many of the small macroaggregates (250-2000 μm) and a large increase in frPOM- 14 C on Day 0. The amount of 14 C released into the frPOM pool with slaking declined with time. In contrast, there was a significant linear increase in the amount of new, root-derived iPOM- 14 C in large microaggregates (53-250 μm) that were released when unstable macroaggregates (>250 μm) slaked. These data support the hypothesis that new microaggregates are formed within existing macroaggregates and provide strong evidence that, in no-till, aggregate formation and stabilization processes are directly related to the decomposition of root-residue and the dynamics of POM C in the soil.
Uptake of phosphorus from dairy wastewater by heterotrophic cultures of cyanobacteria

Abstract The dynamic removal of different forms of dissolved and suspended phosphorus (reactive phosphorus, acid-hydrolyzable phosphorus, organic phosphorus and total phosphorus) by the cyanobacteria Aphanothece microscopica Nageli cultivated heterotrophically in dairy processing wastewater was investigated. Bioreactor performance was highly dependent on operation temperature (10–30°C). Aphanothece microscopica Nageli was able to uptake not only simple phosphorus species (reactive and acid-hydrolyzable phosphorus), but also complex fractions of organically bound phosphorus. Low bioreactor performance was evidenced by the suspended fractions. The conversion of suspended reactive phosphorus and suspended acid-hydrolyzable phosphorus varied between 50.3% and 93.3%. Suspended organic phosphorus and suspended total phosphorus became erratic, with peaks of phosphorus appearing after 8 h of hydraulic detention time and slightly impacting the global phosphorus balance. In addition to phosphorus removal, a good de.
Ultraviolet photodissociation of bromoform at 234 and 267 nm by means of ion velocity imaging

The photochemistry of bromoform is of considerable importance to understanding the impact of short-lived halogen species on bromine chemistry in the atmosphere. In the present work, the products of the ultraviolet photodissociation of bromoform at 234 and 267 nm are determined by time-of-flight mass spectrometry and velocity ion imaging. Both ground Br (2P3/2) and spin–orbit excited Br (2P1/2) atoms are found to be formed via resonance-enhanced multiphoton ionization detection. Radical products are detected via vacuum ultraviolet photoionization at 118 nm. The results indicate that there is a primary molecule bromine elimination channel consisting of CHBr+Br2. The quantum yields for atomic Br and molecular Br2 elimination channels are determined from the time-of-flight spectra to be 0.74 and 0.26 at 234 nm, respectively. At 267 nm, they are 0.84 and 0.16, respectively. Energy and angular distributions are deduced from the 2D images of Br, CHBr, and CHBr2. The direct studies described in this paper on the .
Anellated Hemicyanine Dyes with Large Symmetrical Solvatochromism of Absorption and Fluorescence

A novel class of amphiphilic hemicyanine dyes is described where electron-pushing aniline and electron-pulling pyridinium are joined by anellated benzene rings. Enhancing the solvent polarity, the absorption band of these ANNINE dyes is shifted to the blue and the fluorescence band is shifted to the red at an invariant 00 energy. The increasing Stokes shift spans the whole visible spectrum. The divergent symmetrical solvatochromism of the positively charged chromophores is parametrized by a monopole−dipole model using a Born−Onsager−Marcus approach. From the intramolecular charge shift that is induced by electronic excitation, the linear Stark effect that is expected when the ANNINE dyes are used as voltage-sensitive probes in a biomembrane is estimated.
Improving the Removal Efficiency of Elemental Mercury by Pre-Existing Aerosol Particles in Double Dielectric Barrier Discharge Treatments

ABSTRACTPlasma technology has been employed for the removal of gaseous elemental mercury (Hg0) from simulated flue gases without pre-existing airborne particles. This study developed a double dielectric barrier discharge (DDBD) treatment system, in which two coaxial electrodes were covered by quartz dielectrics, for removing mercury with the presence of aerosol particles. The increase in pre-existing aerosol surface concentration can improve Hg0 removal efficiency up to 160% in the DDBD device. Inorganic aerosol particles (sodium chloride) perform better than organic ones (sucrose) in improving Hg0 removal efficiency. These aerosol particles can be collected in the DDBD system. For sodium chloride particles, a collection efficiency of more than 90% was observed in the tested diameter range of 10–100 nm. The improvement in Hg0 removal with the presence of particles is possibly due to that (i) aerosol particles provide additional surface for surface-induced Hg0 oxidations, (ii) reactive species (such as Cl) generated by plasma etching particle surface rapidly react with Hg0, and (iii) charged particles can in-flight adsorb mercury species.
Analysis of Reaction Rate between Solid Carbon and Molten Iron by Mathematical Models

The factors affecting the carbon dissolution rate into liquid iron and the interdependency between these rate influencing factors were discussed with aid of a kinetic model. These rate influencing factors include temperature, carbon structure, interfacial active elements, metal composition, liquid agitation, wettability between solid and liquid, solid particle size, ash in carbonaceous materials and side reactions.Experiments were carried out on carbon dissolution from graphite and coke into liquid Fe-C alloy using resistance or induction furnaces at 1573-1873 K. The kinetic parameters describing carbon dissolution rate were obtained from the comparison of observed carbon dissolution rates and model calculations. The dissolution rates at higher temperatures or in an induction furnace were found more rapid than those at lower temperatures or in a resistance furnace. The mass transfer in liquid was found to be the major limiting step for the carbon dissolution process.
N-(2-Iodophenylmethyl)hexamethylenetetraminium bromide dihydrate

The title compound, C13H18IN4+·Br−·2H2O, is a quaternary ammonium salt derived from 2-iodo­benzyl bromide and hexa­methyl­enetetra­mine. Two water mol­ecules per asymmetric unit act as hydrogen-bond donors to the bromide anion. Direct cation–anion contacts are established via C—H donors, mainly from methyl­ene groups in the α position to the ammonium centre.
Mechanism and kinetics of the reduction of magnetite to iron during heating in a microwave E-field maximum

The time-resolved x-ray diffraction method was applied in situ to investigate the carbothermal reduction of magnetite by carbon black in a 2.45 GHz microwave field. The kinetics of the phase transformation sequence is analyzed within the Kolmogorov–Johnson–Mehl–Avrami formalism. The first reduction stage is the solid-state transition of magnetite to wustite, followed by the partial conversion of nearly stoichiometric wustite to iron. The kinetics of the initial reduction of Fe3O4 to primary wustite is phase boundary controlled. Behind the reaction front, primary wustite rapidly evolves toward stoichiometric FeO. Cation vacancies and the dynamic clustering of structural defects influence the kinetics of the reduction of the nearly stoichiometric secondary wustite to porous iron.
Organic chemistry of calcium. 3. Steam stripping of metal phenoxides liberates phenol and regenerates the metal hydroxide

Treatment of hydroxycalcium phenoxide (HOCaOC 6 H ) , sodium phenoxide, and potassium phenoxide with steam at 350 ° C and atmospheric pressure liberated phenol and regenerated the corresponding metal hydroxide. High phenoxide conversions in the range 85-100% were obtained, even though the reaction conditions were not optimized. Essentially quantitative recoveries of the hydroxide bases were obtained. The steam stripping reaction appears to be generally applicable to alkali and alkaline-earth phenoxides. Metal phenoxides are produced when phenol-containing process streams are contacted with basic hydroxides for phenol removal
ODOROUS EMISSIONS AND ODOR CONTROL IN COMPOSTING SWINE MANURE/SAWDUST MIXES USING CONTINUOUS AND INTERMITTENT AERATION

Swine manure mixed with sawdust was composted in 205 L pilot–scale vessels. Four runs with a total of 22 vessel studies were made during 1998 and 1999. Composting was conducted, with either continuous or intermittent aeration supplied to each vessel, for 17 to 29 days. Temperatures, airflow, carbon dioxide production, oxygen uptake, and ammonia production were monitored. Material masses, moisture contents, pH, and various chemical concentrations were determined for initial and final samples. Further, in the final two runs, condensate from the exhaust air stream from each vessel was collected using water–cooled condensers (40 cm, 15 C) and weighed every 12 hours. Condensates and extracts from initial and final material samples were analyzed by gas chromatograph with flame ionization detector for volatile fatty acids (VFAs). The results indicated that airflow had a strong effect on emissions. Ammonia release showed a linear trend vs. total airflow, with about 50% reduction in ammonia occurring for a 75% reduction in airflow. Acetic, propionic, and butyric acid emissions were reduced by 68%, 68%, and 33%, respectively, and isobutyric, isovaleric, and valeric acid emissions were increased by 151%, 8%, and 18% for a similar airflow reduction. Thus, there is potential for reduced odors with reduced airflow. Results also indicated that initial pH influenced onset of composting and the potential for odor release. For vessels with initial pH below 5.95, compost heating was slow, and temperature and CO2 production patterns indicated gradual development of, and shifts between, mesophilic and thermophilic bacterial activity. For vessels that started at higher pH values, development was much more rapid. These effects, combined with the fact that a significant majority of the VFAs initially present were not emitted but were not present at the end of the runs (particularly in the higher pH vessels), indicated that high bacterial activity was important for reduction of odor potential.