Miracle-dz/UniFAR-FTUs huggingface dataset:
Heavy-liquid separation and x-ray diffraction analysis of airborne particulates

This paper describes the x-ray diffraction analysis of the fractions of airborne particulates obtained by the heavy-liquid separation method with a series of carbon tetrachloride-methylene iodide mixtures. The analytical results for the samples collected from office, business, and industrial districts are compared. The method is recommended for use in the study of airborne particulates.
31P-NMR-spectroscopic investigations of NaOH-extracts from soils with different land use in Yucatan (Mexico)

In aqueous NaOH-extracts of top-soils (0-10 cm) from typic chromuderts, phosphorus was determined by NMR-spectroscopy. In addition to inorganic orthophosphate, orthophosphate monoesters and diesters were detected. Pyrophosphate was only found in traces after clear-cutting and burning of the forests. The result of clear-cutting and agricultural land use is an increase of inorganic P from 19% (forest) to 33% (maize field). Compost gardens and mature tree gardens contain only 9-13% inorganic P in the NaOH-extract. The organic P-fraction consists mainly of orthophosphate monoesters (57-72%). The orthophosphate diester content is only 10–21%. It could be shown, that the increase of inorganic P in the course of clear-cutting and ploughing is correlated with a decrease of orthophosphate mono- and diesters. 31P-NMR-spektroskopische Untersuchungen von NaOH-Extrakten unterschiedlich genutzter Boden in Yucatan (Mexiko) Im NaOH-Extrakt von Oberboden (0-10 cm) unterschiedlich genutzter Typic Chromuderts wurden die P-Formen NMR-spektroskopisch bestimmt. Neben anorganischem Orthophosphat konnten Orthophosphat-Monoester und Orthophosphat-Diester nachgewiesen werden. Pyrophosphat-P fand sich nur in Spuren. Rodung der Walder und Ackernutzung bedingen einen Anstieg der anorganischen P-Formen von 19% (Sekundarwald) auf etwa 30%. Kompostbeete und mehrstockige Baumgarten mit Gemuseanbau und Kleintierhaltung im Unterstand weisen nur 9-11% anorganisches Orthophosphat im NaOH-Extrakt auf. Die organische P-Fraktion besteht im wesentlichen aus Orthophosphat-Monoester (57-72%); die Diester treten mit 10-21% in den Hintergrund. Es zeigt sich, das der nach Rodung festzustellende Anstieg an anorganischem Orthophosphat zu Lasten der Mono- und Diester geht.
Resolution of the Translation—Rotation Paradox in the Theory of Irreversible Condensation

In this paper it is shown that the Lothe and Pound correction to nucleation theory based upon the introduction of translational and rotational partition functions for individual drops does not arise. The error originates in the improper assumption that the free energy assigned to a drop, in the conventional theory of nucleation, corresponds to that for a drop whose center of mass is stationary.
Influence of TiO2 Nanoparticle Size on Electron Diffusion and Recombination in Dye-Sensitized TiO2 Solar Cells

Nanoporous electrode films are prepared from different sized anatase TiO2 nanoparticles, of which the average diameter is 14, 19, and 32 nm. Dye-sensitized solar cells are prepared from the films. Diffusion coefficients of electrons (D) in the solar cells are estimated by photocurrent transient measurements using a small-intensity laser pulse under continuous irradiation of bias light. Electron recombination lifetimes (τ) in the solar cells are measured by intensity-modulated photovoltage measurement (IMVS). It is found that the D increases and τ decreases with the increase of the particle size up to 32 nm. The increase of the D is interpreted with the decrease of the film surface area, where the charge trap sites are likely to exist, and the condition of grain boundary. The decrease of τ is discussed with the change of surface area and D with the particle size.
Ruthenium(II) Complexes of Carboxylated Terpyridines and Dipyrazinylpyridines

One-pot preparations of carboxylated 2,2';6',2"-terpyridine and 2,6-dipyrazin-2-ylpyridine ligands are reported in free acid and ester forms, as well as their transformations to homoleptic Ru II complexes in very good yields. Density functional theory calculations of their geometry-optimized structures enabled their comparison with crystal structures; although the gross features of the crystal structures were reproduced, they showed much variability and distortion. The spectroscopic and electrochemical properties were analyzed from the point of view of their geometry-optimized structures, molecular orbital characteristics and electronic transitions, specifically to assess the effects of carboxylation and of inserting a phenylene spacer between the tridentate portion and the carboxyl group. The dipyrazinylpyridine complexes had HOMO levels stabilized by approximately 1 eV relative to the terpyridine analogues, and showed positive-shifted electrochemical potentials and redshifted electronic absorptions. Phenylene spacers were found to act as electron-donating groups, and the lowest-energy UV/Vis transitions showed intraligand character.
Crystal structure of Na4[Cu4O2(SO4)4] MeCl (Me: Na, Cu, ⃞) the synthetic Na-analogue of piypite (caratiite)

Abstract The crystal structure of Na4[Cu4O2(SO4)4] MeCl (Me: Na, Cu, ⃞) has been solved by direct methods and refined to R1 = 0.028 using 2466 independent reflections. The compound is tetragonal with space group P4/n, a= 18.451(1) Å, c = 4.9520(2) Å, Z = 4. The two main building units running parallel to the c-axis comprise: (1) slabs containing SO4 and OCu4 tetrahedra; and (2) chains of corner sharing Me(Cl,O)6 octahedra. The displacement ellipsoids of the atoms occupying the Me sites and of the Cl ions indicate a short-range static disorder. Copper in the slabs exhibits a (4+1) coordination. Both elements form a tunnel structure in which additional Na atoms are incorporated for charge compensation. The structure is closely related to the mineral piypite (K4Cu4O2(SO4)4MeCl (Me: Na, Cu, ⃞)): a ≈ √ 2 . apiy. ; c ≈ cpiy. Furthermore, the structure has a pronounced pseudo-translational symmetry: apart from some of the oxygen sites, all of the nineteen crystallographically distinct positions are related by a pseudo F centring.
FTIR study of the thermal transformation of barium-exchanged zeolite A to celsian

In this study room temperature X-ray diffraction patterns and FTIR spectra of zeolite A in its Na form, Ba-exchanged zeolite A, hexacelsian, monoclinic celsian and Ba-exchanged zeolite A samples thermally treated at temperatures ranging from 200 to 1000 °C are reported. The combined inspection of room temperature X-ray diffraction patterns and FTIR spectra reveals the following points. 1) The thermal collapse of the microporous zeolite structure goes to completion upon thermal treatment at 200–300 °C; in the resulting amorphous phase the presence of the secondary building units of the zeolite A structure may be detected. 2) Thermal treatment in the temperature range 200–400 °C results in a middle-range order which favours the crystallisation of small crystallites of monoclinic celsian at 500 °C. 3) The further evolution of the amorphous phase in the 500–800 °C temperature range of thermal treatment instead of promoting the crystalline growth of monoclinic celsian, creates a middle-range order favourable to the crystallisation of hexacelsian which occurs at 1000 °C.
Linear Stability of Natural Convection Induced by Absorption of Radiation in a Parallelepiped Cavity

This study focuses on the marginal stability of internally heated natural convection flow due to the absorption of incoming radiation in a parallelepiped cavity. The study is motivated by possible limnological applications where natural convection is known to have a significant impact on transport and mixing phenomena. The absorption of incoming radiation by a water body follows Beer's law, and any residual radiation reaching the bottom is absorbed by the bottom and re-emitted as a boundary flux. A potentially unstable bottom thermal boundary layer forms below a layer of stable thermal stratification, which exponentially decays from the water surface. The thermal structures evolve with time, and hence the pattern formation and critical conditions of the convective instability vary with time. A frozen-time model is employed in the present study and the base flow solution is assumed to be quasi-static for the evolution of perturbation. Despite a large body of literature available for the classical Rayleigh-Benard convection, the stability analysis on internally heated convection within a confined domain is very limited. The purpose of the present study is to investigate the dependence of three-dimensional pattern formation and critical conditions on the aspect ratio of the cavity and the water depth, and their time
Biosorption of uranium and thorium

Selected samples of waste microbial biomass originating from various industrial fermentation processes and biological treatment plants have been screened for biosorbent properties in conjunction with uranium and thorium in aqueous solutions. Biosorption isotherms have been used for the evaluation of biosorptive uptake capacity of the biomass which was also compared to an activated carbon and the ion exchange resin currently used in uranium production processes. Determined uranium and thorium biosorption isotherms were independent of the initial U or Th solution concentration. Solution pH affected the exhibited uptake. In general, lower biosorptive uptake was exhibited at pH 2 than at pH 4. No discernible difference in uptake was observed between pH 4 and pH 5 where the optimum pH for biosorption lies. The biomass of Rhizopus arrhizus at pH 4 exhibited the highest uranium and thorium biosorptive uptake capacity (g) in excess of 180 mg/g. At an equilibrium uranium concentration of 30 mg/liter, R. arrhizus removed approximately 2.5 and 3.3 times more uranium than the ion exchange resin and activated carbon, respectively. Under the same conditions, R. arrhizus removed 20 times more thorium than the ion exchange resin and 2.3 times more than the activated carbon. R. arrhizus also exhibited higher uptake and a generally more favorable isotherm for both uranium and thorium than all other biomass types examined.
Lattice Parameters, Ionic Conductivities, and Solubility Limits in Fluorite‐Structure MO2 Oxide [M = Hf4+, Zr4+, Ce4+, Th4+, U4+] Solid Solutions

Changes in the lattice parameters of fluorite type MO2 oxides (M = Hf4+, Zr4+, Ce4+, Th4+, U4+) due to the formation of solid solutions can be predicted by proposed empirical equations. The equations show the generalized relationship between dopant size and ionic conductivity in the binary systems of these oxides, illustrating that the smaller the difference between the dopant ionic radius and the critical dopant radius, the higher the conductivity. The solubility limit of the same periodic group elements in fluorite-structure MO2 oxides decreaes linearly with the square of Vegard's slope for each solute as determined from the proposed equations.
Thermal and chemical contributions of added H2O and CO2 to major flame structures and NO emission characteristics in H2/N2 laminar diffusion flame

Numerical simulation with detailed chemistry has been carried out to clearly discriminate the thermal and chemical contributions of added diluents (H2O and CO2) to major flame structures and NO emission characteristics in H2/N2 counterflow diffusion flame. The pertinence of GRI, Miller–Bowman, and their recent modified mechanisms are estimated for the combined fuel of H2, CO2, and N2. A virtual species X, which displaces the individual CO2 and H2O in the fuel sides, is introduced to separate chemical effects from thermal effects. In the case of H2O addition the chain branching reaction, H + O2 → O + OH is considerably augmented in comparison with that in the case of CO2 addition. It is also seen that there exists a chemically super‐adiabatic effect in flame temperature due to the breakdown of H2O. The reaction path of CH2O→CH2OH→CH3 and the C1‐branch reactions become predominant due to the breakdown of CO2. In NO emission behaviour super‐equilibrium effects caused by the surplus chain carrier radicals due to the breakdown of added H2O are more superior to the enhanced effects of prompt NO with the breakdown of added CO2. Especially, it is noted that thermal NO emission is directly influenced by the chemical super‐equilibrium effects of chain carrier radicals in the case of H2O addition. As a result the overall NO emission in the case of the addition of H2O is higher than that in the case of CO2 addition. Copyright © 2002 John Wiley & Sons, Ltd.
Evaluation of Traffic-Related Heavy Metals Emissions Using Noise Barrier Road Dust Analysis

The impact of traffic emissions on the environment close to an arterial road often is assessed on the basis of heavy metal pollution of road dust collected directly from or close to the road surface. In our work we propose an assessment of a potential environmental hazard on the basis of an analysis of the content of heavy metals in the road dust trapped on vertical acoustic barriers installed directly by roads. This kind of road dust appeared to be a good indicator of traffic related to heavy metals emissions. The pollution level of Cu and Zn reached the category of “extreme level. ” An increased level of Cu was found on a decelerating activity section. A good correlation between Cu, Mn, and Fe may imply that brake wear is also an important source of iron and manganese. It has been shown that high concentration of Zn is a result of its release from zinc-plated road furniture.
Quality of Mince from Alaska Pollock (Theragra chalcogramma) Frames

The quality and frozen stability of minces produced from Alaska pollock (Theragra chalcogramma) frames were compared against commercially produced fillet mince. Fresh frame mince had a higher defect level, lower nutritional content, and darker color. Cooked frame mince had a softer texture than commercial mince. After 6 mo frozen storage, frame mince had deteriorated to where it had unacceptable color, flavor and cooked texture. Rancidity increased more rapidly in frame mince than commercial fillet mince. Blending frame mince at levels of 10% to 20% with commercial mince produced acceptable fresh quality but marginal frozen storage stability.
Physically representative network models of transport in porous media

The authors calculate permeabilities for a class of granular porous media derived from a real, disordered packing of equal spheres. The entire structure, including pore space, of these media is completely specified by the radii and spatial locations of the constituent grains. When geometric nearest neighbor grains are grouped together, the structure may be subdivided into pore bodies and pore throats in a natural and unambiguous way. From this subdivision one can establish a network of flow paths whose geometry and topology are completely specified, so that permeability and other transport coefficients can be calculated directly and without any adjustable parameters. The calculations focus on processes that form porous media, rather than on specific examples of such media. Hence, the approach is essentially predictive, rather than correlative. No additional measurements (such as capillary pressure data or pore system data from thin sections) are required, and correlations between permeability and other properties are not used. Predicted permeabilities match measurements on sandstone sample similar to the model porous media studied here over a wide range of porosity. Geometrical attributes of the network representation of the pore space of the model media are found to be spatially correlated. This departure from randomness significantlymore » affects permeability. The agreement between predictions and measurements suggests that spatial correlation is inherent in granular porous media and that uncorrelated network models are therefore unlikely to be physically representative of such media. « less
Premixed turbulent flame structures in moderate and intense isotropic turbulence

Several 2-D imaging techniques including planar laser induced fluorescence for OH (OH-PLIF) have been used to investigate premixed turbulent flame structures under moderate to intense isotropic turbulence. Unconditioned velocity statistics were measured by laser Doppler anemometry. The experiments used a low-swirl burner that produces high intensity near-isotropic turbulence. The goal is to gain better insights into the flame structures at high turbulence and to test and verify the concept of the "distributed reaction zones" regime. Four methane/air flames (φ=0.7) have been studied with 0.5< u ′<2.2 m/s. A linear correlation for the flame speed, S f , is found: S f / S L =2.12 ( u ′/ S L )+1. Sets of 200 OH-PLIF images obtained for each flame clearly show that flame wrinkling is a random process. The probability of the flame having very small wrinkles is relatively low. This strongly suggests that the penetration of small intense eddies into the flame sheet to generate a "distributed reaction zone" is statistically an extremely rare event. The OH-PLIF images were processed to determine statistical properties of the mean flame curvatures and flame lengths for comparison with turbulence intensity and turbulent length scales. The results show that the increase in turbulent kinetic energy generates larger mean curvatures of the flame fronts, and a linear increase in the flame surface area ratio estimated from the mean flame length measurement.
A survey of the occurrence and properties of methicillin-resistant Staphylococcus aureus and methicillin-resistant Staphylococcus intermedius in water buffalo milk and dairy products in Turkey

Antimicrobial resistance, β-lactamase activity and mecA gene of Staphylococcus aureus and Staphylococcus intermedius isolated from raw water buffalo milk and dairy products in Turkey were determined. All strains showed resistance to at least one antibiotic but none was resistant to vancomycin. Of the 97 S. aureus and 35 S. intermedius strains, 9 (9.2%) and 2 (5.7%) were resistant to oxacillin and harboured mecA gene. β-lactamase activity of 13.4% and 5.7% of S. aureus and S. intermedius strains was positive, respectively. Overall, 2.5% and 0.55% of the samples were contaminated with methicillin-resistant S. aureus and S. intermedius, respectively.
Bacterial Bioaerosol Concentrations in Public Restroom Environments

The number concentrations of total culturable bacterial bioaerosols in seven public restroom environments were measured via a standard measurement method provided by the Ministry of Environment of the Republic of Korea. Outdoor bioaerosols were also measured to compare with data collected in public restrooms. The measurements were conducted for one year, with varying concentrations of airborne bacterial bioaerosols observed in public restrooms. The effect of the number of users on the concentration of bioaerosols in public restrooms was also analyzed. The experimental results provided useful and basic information for the study and development of control methods against bioaerosols in public restrooms.
Atmospheric nanoparticles and climate change

F or several decades, chemical engineers have been studying the atmosphere as a vast chemical reactor to understand air pollution and climate change. Predicting future climate change requires accounting not only for greenhouse gases but also atmospheric particles and their interactions with clouds. Homogeneous nucleation of nanoparticles, first detectable when they are 1–3 nm, has been frequently observed in the atmosphere, but the chemistry driving their formation is still mysterious. This process may affect the climate; if these particles can grow to 100 nm dia. , they will modify the optical properties of clouds by serving as cloud nucleation sites. In most areas, growth of nanoparticles is dominated by organic oxidation chemistry that is also not well understood. This perspective article will survey the state of knowledge on these issues, highlight recent progress including contributions from chemical engineers, and point to promising future research areas. The next section provides background information about climate change and the role of atmospheric particles in the climate system. The section Gases and Nanoparticles discusses how nanoparticles form in the atmosphere with an emphasis on recent advances in the instruments that measure these processes. The fate of these nanoparticles and their potential to grow large enough to affect clouds is the subject of the section titled Nanoparticles to Cloud Condensation Nuclei. The section A Global Picture of CCN, Clouds, and Climate, places these processes in a global context by reviewing their incorporation into global climate models.
Environmental monitoring for linear alkylbenzene sulfonates, dialkyltetralin sulfonates and their biodegradation intermediates

Concentrations of linear alkylbenzene sulfonates (LAS), dialkyltetralin sulfonates (DATS), and their biodegradation intermediates are reported for the influents and effluents of 10 U.S. domestic wastewater treatment plants as well as upstream and downstream river waters and sediments. Three types of treatment facilities in 10 U.S. states were sampled and analyzed. Removals were calculated based on initial concentrations of LAS and DATS. A derivatization electron capture/gas chromatography/mass spectrometry method was employed. Its increased sensitivity and selectivity permitted the determination of environmental levels of LAS, DATS, and their biodegradation intermediates at low micrograms per liter (ppb) concentrations. The removal from four activated sludge and five trickling filter wastewater treatment facilities averaged 99.5% and 82.9% for LAS and 99.1% and 97.3% for LAS intermediates, respectively, for the activated sludge and trickling filter facilities. In the same plants, percent removals for DATS averaged 95% and 63.2% and DATS intermediates 59.1% and 58.7%, respectively. The removals obtained by a rotating biological contactor were similar to those observed in the activated sludge wastewater treatment facilities.
Leaf and root volatiles produced by tissue cultures of Alpinia zerumbet (Pers.) Burtt & Smith under the influence of different plant growth regulators

Volatiles produced by plantlets of Alpinia zerumbet were obtained by means of simultaneous distillation-extraction (SDE). The effects of indole-3-acetic acid, kinetin, thidiazuron and 6-benzylaminopurine on leaf and root volatile composition obtained by tissue cultures were investigated. A higher content of b-pinene and a lower content of sabinene were observed in leaf volatile of plantlets cultured in control, IAA and IAA+ TDZ media, as compared with those of donor plants. In vitro conditions were favorable to increase caryophyllene content. Volatile compounds from the root were characterized mainly by camphene, fenchyl-acetate and bornyl acetate; which constitute about 60% of total volatile.
Plausible guard effect on the active sites of heterogeneous Ziegler–Natta catalyst by coordinating monomers and growing polymer chains in the initial stage of propene polymerization

Investigation of propene polymerization by a modified stopped-flow technique using TiCl4/ethylbenzoate(EB)/MgCl2 Ziegler–Natta catalyst with or without pretreating the catalyst with triethylaluminium (TEA) within an ultra-short period (ca 1 s) was conducted to gain new understanding of the nature of active sites related to TEA in the early stage of polymerization. When the catalyst was pretreated by a cocatalyst, deactivation behaviour was clearly observed, even within an extremely short pretreatment period. In contrast, without pretreatment, the deactivation of active sites can be neglected within the polymerization period indicating that the activated Ti species might be protected from deactivation by TEA when monomer is present in the system. A plausible guard effect on the active sites by coordinating monomer and growing polymer chains in the initial stage of polymerization is proposed to account for this phenomenon. Copyright © 2004 Society of Chemical Industry