Miracle-dz/UniFAR-FTUs huggingface dataset:
Total Organic Carbon (TOC) as a Sum Parameter of Water Pollution in Selected Polish Rivers (Vistula, Odra, and Warta)

This paper reports on total organic carbon (TOC) and its fractions dissolved organic carbon (DOC) and particulate organic carbon (POC) studied in different Polish rivers. The samples investigated came from the Vistula, Odra, and Warta rivers, and were compared with similar data on river waters available in the literature. The DOC concentrations ranged from 10.0 to 14.2 mg/L and did not vary during the vegetative season. The POC values considerably increased frqm May through September and reached a maximum in summer. Results for the years 1991-1996 evidenced a significant increase in the POC value for the Polish rivers from 10.8 to 24. 5 mg/L, in comparison with analogous values for West European rivers and North American ones. The enhanced values of TOC and POC were interpreted as being due to anthropogenic pollution.
Non-conventional hydrogen bonds

Hydrogen bonds (HBs) are the most important ‘weak’ interactions encountered in solid, liquid and gas phases. The HB can be defined as an attractive interaction between two molecular moieties in which at least one of them contains a hydrogen atom that plays a fundamental role. Classical HBs correspond to those formed by two heteroatoms, A and B, with a hydrogen atom bonded to one of them and located approximately in between (A–H···B). Recently, knowledge of the number of functional groups which act as hydrogen bond donors or acceptors has increased considerably and most of these new groups are discussed.
Chiral compounds of essential oils. Part XVI. enantioselective multidimensional gas chromatography in authenticity control of balm oil (melissa officinalis l.)

Using enantioselective multidimensional gas chromatography (enantio-MDGC) and the column combination polyethylene glycol/heptakis (2,3-di-O-acetyl-6-O-ter-butyldimethylsilyl)-β-cyclodextrin in OV 1701-vi, the chiral monoterpenoids cis/trans-rose oxides, octan-3-ol, oct-1-en-3-ol, linalol, citronellal, citronellol and citronellic acid methyl ester were stereoanalysed. The method is applied to chirality evaluation of these compounds from balm oils. The enantiomeric distributions are discussed in order to assess the authenticity of this essential oil
High-pressure synthesized materials: treasures and hints

This short review covers some particular aspects of the production of new materials under high pressures. Despite the fact that there is an extremely wide range of new high-pressure synthesized substances with unique properties, a commercial synthesis has been used up to date only for producing superhard materials – these are real treasures of today’s industry. At the same time, as should be underlined here, high-pressure experiments often give scientists material with helpful hints of what new intriguing substances can exist in principle. This is true both for new superhard, semiconducting, magnetic, superconducting, optical materials already synthesized under pressure and a large number of hypothetic new polymers from low-Z elements.
Solubility and hydrolysis of HCFC-22 (CHF2Cl): Upward revision of rate constants for aqueous reactions of CHF2Cl with OH− at elevated temperature

Henry's law constants of CHF2Cl in water at temperature T in K, KH(T) in M atm−1, were determined to be ln(KH(T))=−(11.1±1.5)+((2290±500)/T) at 313–363 K by means of a phase ratio variation headspace method. The temperature-dependent rate constants for aqueous reactions of CHF2Cl with OH−, k(T) in M−1 s−1, were also determined to be 3.7×1013exp(−(11, 200/T)) at 313–353 K, by considering the gas–water equilibrium, the aqueous reaction at room temperature, and liquid-phase diffusion control. The liquid-phase diffusion control was approximated with a one-dimensional diffusion first-order irreversible chemical reaction model. The k(T) value we determined is 10 times (at 353 K) or 3 times (at 313 K) as large as the value reported (R. C. Downing, Fluorocarbon Refrigerants Handbook, Prentice Hall: Englewood Cliffs, NJ, 1988). This upward revision of k(T) indicates that the removal efficiency of CHF2Cl directly through the hydrolysis (CHF2Cl + OH−) is higher than previously expected at temperatures, such as 353 K, relevant to wet flue gas cleaning systems for ozone-destruction substance-destruction facilities. © 2011 Wiley Periodicals, Inc. Int J Chem Kinet 43: 639–647, 2011
Structural Features of Surface Layers of Bifunctional Polysiloxane Xerogels Containing 3-Aminopropyl Groups and 3-Mercaptopropyl Groups

Polysiloxane xerogels containing both –SH and –NH2 functions have been prepared using the sol–gel method with alkoxysilane precursors [such as Si(OEt)4, (MeO)3Si(CH2)3SH and (EtO)3Si(CH2)3NH2]. Molar ratios of 3.2:1, 1.1:1 and 0.4:1 for the two functions –SH and –NH2 were employed. Xerogels which contain only one of the two functions were also synthesized for comparative purposes. It was shown that the use of stannic compounds as catalysts for xerogels with 3-mercaptopropyl groups resulted in a product which possessed a non-porous structure, while the use of fluoride ions allowed the synthesis of a sample with a porous structure (Ssp = 216 m2/g, Vs = 0.152 cm3/g, d = 3.5 nm). Xerogels with a bifunctional surface layer possess a bimodal structure. Infrared, Raman and multinuclear solid-state NMR (1H, 13C, 29Si) spectroscopy data showed: (i) the absence of deprotonation for the 3-mercaptopropyl groups in the bifunctional surface layer of the xerogels; and (ii) that 3-aminopropyl groups form hydrogen bonds in these surface layers. The type of hydrogen bond formed depends on the ratio of the amount of water to the amount of 3-aminopropyl groups in the surface layer. When this ratio is about 1:1, the amino group forms a hydrogen bond with the silanol group associated with the water molecule. Re-organization of the surface layer is observed when the amount of water decreases, the amino groups forming hydrogen bonds between themselves. Hence, the system of hydrogen bonds in the surface layer of such xerogels depends primarily on the drying regime employed for the samples.
Exploring the Role of C-H-II Interactions on the Structural Stability of Membrane Proteins

ABSTRACT ABSTRACT ABSTRACT C-H. π interactions are known to be important contributor s to protein stability. In this study, we have anal yzed the influence of C-H…π interactions on the structural stability of membra ne proteins. In the data set, a total of 408 C-H…. π interactions were observed. The most prominent rep resentatives are the interactions between aromatic C-H donor groups and aromatic π acceptors. Ninety four percent of the C-H…. π interactions between side chain to side chain and remaining six percent of the C-H…. π interactions were observed between side- chain to side-chain five-membered aromatic ring. Long-range C-H…. π interactions are the predominant type of interactions in membrane proteins data set. The secondary structure preference, solvent accessibili ty and stabilization centers of C-H…. π interacting residues were estimated. Moreover, the study shows that 72% of the donor residues and 68% of the acceptor residues are highly conserved. It is concluded that the C -H…. π interaction can, indeed, be categorized as a true s tabilizing force in membrane proteins.
Mechanism of Strong Luminescence Photoactivation of Citrate-Stabilized Water-Soluble Nanoparticles with CdSe Cores

CdSe and CdSe@CdS semiconductor nanocrystals have been synthesized in aqueous solutions, using sodium citrate as a stabilizer. Although initially these quantum dots display photoluminescence with very low quantum yields, upon prolonged illumination with visible light, enhancements up to 5000% have been measured. This leads to aqueous quantum dots with high luminescence, which can have important implications in biological and other applications. A distinct correlation between the photocorrosion process and the photoactivation process is observed. The primary reason for luminescence enhancement is considered to be the smoothing of the CdSe core surface. Importantly, even stronger activation was observed in silica- and CdS-coated nanocolloids where the CdSe core was expected to be shielded from photocorrosion. Preferential adsorption of oxygen molecules in the porous silicate shell accelerates the photocorrosion process. In CdS-coated particles, incomplete coating of the original particles is postulated, whi.
Interpretation of heavy metal speciation in sequential extraction using geochemical modelling

Environmental context Heavy metal pollution is a worldwide environmental concern, and the risk depends not only on their total concentration, but also on their chemical speciation. Based on state-of-the-art geochemical modelling, we pinpoint the heavy metal pools approached by the widely used sequential extraction method. The finding of this paper can help users of sequential extraction methods to better interpret their results. Abstract In this study, the metal (Cd, Cu, Zn and Pb) fractionation determined by selective sequential extraction (SSE) was compared with metal speciation calculated using a geochemical model, the Multi-Surface Model (MSM). In addition, the sources of Cd, Cu and Zn extracted in the SSE were identified with the help of the modelling. The results showed that the SSE-based Cd fractionation contradicted the modelled results, with the organic-bound Cd as respectively the least and the most important species. This contradiction was explained by the model and was attributed to the weak specific adsorption of Cd to organic matter; For Cu, a good agreement was found between SSE and model fractionation, both recognising organic-bound Cu as the most dominant fraction. The high affinity of organic matter for Cu reduced the degree of Cu extracted in steps preceding the oxidation step. The SSE measured a larger exchangeable Zn fraction than the model predicted, which could be explained by Zn extracted from organic-bound, oxide-bound forms, and certain rapidly dissolvable Zn-minerals if present. Zinc in the micropores of minerals was probably not extracted in 0.43M HNO3, thus was not included in the modelling for adsorption calculation, which could explain to a certain extent the larger amount of oxide-bound Zn determined in the SSE than calculated in the model. The modelling results for Pb were less reliable than for other metals because of a poor accuracy of Pb concentration in solution predicted. The findings of this paper can help users of the sequential extraction methods to better interpret their results.
On the ratio T2/T1 for non‐Ohmic spectral densities

Defining T1 and T2 to be the population and phase relaxation times, respectively, for a two‐level system coupled to a bath, previous work for Ohmic spectral densities has shown, surprisingly, that in some instances T2≳2T1. This note shows that this inequality can also be realized for non‐Ohmic spectral densities.
Kinetics of OH radical reaction with phenanthrene: New absolute rate measurements and comparison with other PAHs

Using an in situ pulsed laser photolysis/pulsed laser-induced fluorescence/technique, the OH reaction kinetics of a three-ring polycyclic aromatic hydrocarbon (PAH), phenanthrene (and its deuterated form), was investigated over the temperature range of 373–1000 K. This study represents the first examination of the OH kinetics for phenanthrene at elevated temperatures using the absolute rate technique. The phenanthrene results indicate a temperature dependence similar to its isomer anthracene, reported previously in R. Ananthula, T. Yamada, and P. H. Taylor, J Phys Chem A 2006, 100, 3559–3566, over a similar temperature range. The phenanthrene rate constants are similar to anthracene at high temperature (ca. 1000 K) and a factor of ca. 2 lower at low temperatures (373–700 K). The rate measurements were best fitted by the following two-parameter expression of the form ATn: k1(373–1000 K) = 4.98 ± 2.96 × 10−6 * T−1.97±0.10 (in units of cm3 molecule−1 s−1, error limits ±1σ). Rate measurements with deuterated phenanthrene below 725 K were indistinguishable from the phenanthrene rate measurements, within random error limits, providing strong evidence for an OH-addition mechanism. The effects of PAH size on their reactivity with OH radicals based on selected data over the temperature range of 243–1200 K are discussed. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 629–637, 2007
Electro kinetic remediation of contaminated habitats.

Electrokinetics (EK) is a process that separates and extracts heavy metals, radionuclides and organic contaminants from saturated or unsaturated soils, sludge, and sediments. A low intensity direct current is applied across electrode pairs that have been implanted in the ground on each side of the contaminated soil mass. The electrical current causes electroosmosis and ion migration (electromigration) and electrophoresis, which move the aqueous phase contaminants in the subsurface from one electrode to the other. Contaminants in the aqueous phase or contaminants desorbed from the soil surface are transported towards respective electrodes depending on their charge. The results of several laboratory studies have demonstrated excellent contaminant removal efficiencies by the use of the electrokinetic process (Pamukcu and Wittle, 1992; Probstein and Hicks, 1993). However, recent field applications of the electrokinetic technology have also shown anomalous results (Guzman et al., 2000; Lageman, 1993), which have been attributed mainly to the interaction of the contaminants with naturally occurring electrolytes, humic substances and mixed wastes which are present in the subsurface (Lageman, 1993; Acer et al., 1994). In order to use electrokinetic remediation in the field successfully, the different geochemical interactions that occur in the field soils under induced electricity must first be accurately determined. In addition, mechanisms and their effects can be altered in order to enhance the removal efficiency of lock in non-critical contaminants in the soil by immobilization. Numerous field studies have proven the commercial viability and technical effectiveness of the electrokinetic remediation. However, there is still a lot of scope and avenues to cover in this newly developed technology which are subject to further research. Key words: Electorkinectics, electromigration, electrolysis, electroosmosis.
Structure of polyethylene after pulse ion beam treatment

Pulse ion beam treatment was employed for polyethylene (PE) surface modification. Ultraviolet, infrared (IR), IR-attenuated total reflection spectroscopy (IR-ATR), and X-ray photoelectron spectroscopy methods, as well as wetting angle measurement, were used for the analysis of PE structural changes. Theoretical calculations and experimental data showed treated PE surfaces to have a layered structure. It was found that the upper layer contains various products of PE oxidation and the lower layer contains products of PE decomposition, that is, condensed aromatic structures.
Derivation of Soil‐Specific Streaming Potential Electrical Parameters from Hydrodynamic Characteristics of Partially Saturated Soils

Water movement in unsaturated soils gives rise to measurable electrical potential differences that are related to the flow direction and volumetric fluxes, as well as to the soil properties themselves. Laboratory and field data suggest that these so‐called streaming potentials may be several orders of magnitudes larger than theoretical predictions that only consider the influence of the relative permeability and electrical conductivity on the self potential (SP) data. Recent work has improved predictions somewhat by considering how the volumetric excess charge in the pore space scales with the inverse of water saturation. We present a new theoretical approach that uses the flux‐averaged excess charge, not the volumetric excess charge, to predict streaming potentials. We present relationships for how this effective excess charge varies with water saturation for typical soil properties using either the water retention or the relative permeability function. We find large differences between soil types and the predictions based on the relative permeability function display the best agreement with field data. The new relationships better explain laboratory data than previous work and allow us to predict the recorded magnitudes of the streaming potentials following a rainfall event in sandy loam, whereas previous models predict values that are three orders of magnitude too small. We suggest that the strong signals in unsaturated media can be used to gain information about fluxes (including very small ones related to film flow), but also to constrain the relative permeability function, the water retention curve, and the relative electrical conductivity function.
A Comparative Study of LES Turbulent Combustion Models Applied to a Low Swirl Lean Premixed Burner

In this study we compare two types of Large Eddy Simulation (LES) turbulent combustion models with experimental data for a low swirl stabilized turbulent lean premixed flame. Such flames are a great challenge to numerical simulations since they are unsteady and sensitive to boundary conditions, and details of the experimental set-up. The two classes of LES turbulent combustion models considered are the flamelet and finite rate chemistry models. Individual models of each category may be very different, but in the former the flame is considered infinitely thin, whereas in the latter the chemical kinetics and the diffusion governs the flame behavior. As representative of the flamelet models we here use a G-equation model, and as representative of the finite rate chemistry models we use the thickened flame model and the partially stirred reactor model. Predictions are being compared with measurement data for an atmospheric low-swirl methane/air flame. The experimental measurement data include data from stereoscopic PIV, filtered Rayleigh scattering and acetone LIF, providing information about the velocity, temperature and fuel distribution. All LES show reasonable agreement with the experimental data, predicting a lifted weakly swirling, flame oscillating back and forth just above the rim of the burner. A more detailed comparison of the predictions with the experimental data show that best quantitative agreement is obtained by one of the finite rate chemistry models, whereas the best qualitative comparison is obtained by the flamelet model. Causes for the difference in qualitative and quantitative behavior are elaborated on in the concluding remarks section. (Less)
Facilitated transport by amine‐mediated poly(vinyl alcohol) membranes for CO2 removal from natural gas

The drive toward greater application of membrane has resulted in its rapid development in natural gas processing industry. In this work, amine-mediated membranes were tailored for CO2 removal from CO2/CH4 stream. The effects of various parameters such as amine concentration, microporous support, feed pressure and composition were examined to study the permeation behavior of pure and mixed gases. Generally, CO2 transport through the DEA-PVA membranes was higher than that of MEA-PVA membranes for approximately 70%. The membrane containing 15 wt% DEA and 35 wt% MEA revealed higher permselectivity. CO2 permeance enhancement of amine-PVA membranes in comparison with neat PVA membrane, confirmed that CO2-amine reaction was the dominant transport mechanism. Additionally, with increasing feed pressure, CO2/CH4 permselectivity decreased due to carrier saturation. However, lower partial pressure of CO2 was in favor of reaction mechanism in pure and mixed gas tests. On the other hand, CH4 is not significantly affected by feed pressure confirming that solutiondiffusion is the governing transport mechanism. Additionally, PTFE support with higher wettability showed better performance (18%) regardless of amine type, concentration and feed pressure. DEA-PVA membrane has exhibited good stability during 2 weeks, unlike MEA-impregnated membrane, which was probably due to carrier degradation over time. POLYM. ENG. SCI., 54:1268–1279, 2014. V C 2013 Society of Plastics Engineers
Nuclear Fuel Management Optimization: A Work in Progress

The focus of this overview for this issue of Nuclear Technology, which contains papers presented at the American Nuclear Society Advances in Nuclear Fuel Management III (ANFM-III) 2004 topical meeting, is to introduce the subject of nuclear fuel management for light water reactors. A total of 23 papers was presented on this topic at ANFM-III. Nuclear fuel management involves making the so-called out-of-core and in-core decisions. Simply put, the out-of-core decisions address the attributes of the new (fresh) fuel that will be fabricated and the partially burnt (shuffled) fuel to reinsert into the core for additional energy production. The in-core decisions address where the fresh and burnt fuel along with burnable poisons should be located in the core. The above applies to batch refueling strategies, e.g., pressurized water reactors and boiling water reactors (BWRs). For BWRs, additional in-core decisions enter to address control rod pattern paired with core flow rate as a function of burnup. It is obvious that the out-of-core and in-core decisions are coupled. The objective of nuclear fuel management is to minimize the cost of electrical energy generation subject to operational and safety constraints. Since fuel resides in the core for several cycles, a multicycle assessment is required to make nuclear fuel management decisions. For nearly four decades there has been an effort to develop automated computational capability to assist the reload core nuclear design engineer in making nuclear fuel management decisions. This development has ranged from employment of heuristic rules to utilization of mathematical optimization approaches. This overview reviews the development of nuclear fuel management optimization capabilities by first defining the problem, then describing current capabilities, and finally projecting where future capabilities need to be developed to support the needs of reload core nuclear design engineers.
Internal rotation in 1,4-dimethylnaphthalene studied by high resolution laser spectroscopy

The high resolution laser induced fluorescence spectrum of the 00 0 S 1(1 A 1) ← S 0(1 A 1) electronic transition in 1,4-dimethylnaphthalene has been studied in a molecular beam. The residual Doppler width of 12 MHz allowed rotational resolution and the study of the effects of the internal rotation of the two methyl groups. All strong lines were assigned and the rotational constants in both the ground and excited electronic states were determined. The internal rotation of the two methyl groups manifests itself in the spectrum by a splitting of each rotational transition into three lines. The splitting of the lines is 40 ± 1 MHz and constant up to J = 11 and K +1 = 11. The intensity ratio of the lines is 1:2:1 within 10 per cent. No further splittings were observed in the investigated frequency range. It is shown that the spectrum is totally explained by the simple model of two independent internal rotors attached to an asymmetric rotor frame. The effect of the interaction of the two rotors is negligible w.