Density of the systems (NaF/AlF<Subscript>3</Subscript>)—AlPO<Subscript>4</Subscript> and (NaF/AlF<Subscript>3</Subscript>)—NaVO<Subscript>3</Subscript>

The densities of two systems of molten mixtures (NaF/AlF₃)—NaVO₃ and (NaF/AlF3)—AlPO₄ were measured using an Archimedean method. Each molten mixture contained varying amounts of “impurity” constituents. The measurements were performed at various NaF/AlF₃ mole ratios (CR, cryolite ratio), equal to 3, 2.5, 2, and 1.5.     

Ten years since Robert C. Mackenzie’s death. A tribute to the ICTA founder

Dr. Robert Cameron Mackenzie was an eminent scientist who gave a major contribution to the progress of science in the fields of thermal analysis and clay minerals. He was a leading figure in the East–West cooperation at times when these relations were politically very difficult. The authors give an outline of his achievements and some personal recollections of his activity.     

Membrane extraction of 1-phenylethanol from fermentation solution

1-Phenylethanol can be produced by biotransformation of acetophenone using microorganisms. The next step is the separation of biomass from the fermentation solution (e.g. using microfiltration) and then the separation of the product. Membrane extraction was studied in the presented work for this purpose. Equilibria of acetophenone and 1-phenylethanol in the equilibrium system solute-organic solvent-water were investigated for three different organic solvents (heptane, toluene, ethyl acetate). On the basis of this investigation, extraction kinetics of both solutes from the model aqueous solution to the heptane organic phase, using a hollow fiber membrane module, were studied. To simulate the extraction kinetics, mathematical model of an experimental parallel flow hollow fiber contactor is presented and verified using experimental values with good agreement. Extraction kinetics for the investigated organic solvents were simulated and compared using the verified mathematical model and the chosen membrane extraction parameters.     

On weighted and locally polynomial directional quantile regression

The article deals with certain quantile regression methods for vector responses. In particular, it describes weighted and locally polynomial extensions to the projectional quantile regression, discusses their properties, addresses their computational side, compares their outcome with recent analogous generalizations of the competing multiple-output directional quantile regression, demonstrates a link between the two competing methodologies, complements the results already available in the literature, illustrates the concepts with a few simulated and insightful examples illustrating some of their features, and shows their application to a real financial data set, namely to Forex 1M exchange rates. The real-data example strongly indicates that the presented methods might have a huge impact on the analysis of multivariate time series consisting of two to four dimensional observations.     

Possibilities for removal of chlorinated dye Mordant Blue 9 from model waste water

This comparative study focused on the different methods used for the treatment of model waste water polluted with the chlorinated acid dye Mordant Blue 9. Low-cost and commercially available ionic liquids — benzalkonium chloride and Aliquat 336 — were applied as liquid ion-exchangers to precipitate the Mordant Blue 9 by way of ion pair formation between the bulky ammonium cations of ionic liquids and anions of the above dye. The decolorisation efficiency of the ionic liquid application and the effect on reduction of the absorbance, adsorbable organic halogens, chemical oxygen demand and biological oxygen demand were compared with the conventional coagulation, sorption and Fenton oxidation techniques.     

Radical-scavenging activity of glutathione,chitin derivatives and their combination

Since chitosan and its amino-, cinnamo- or cinnamo-amino- derivatives are acid-soluble, the effect of acetic acid on hyaluronan (HA) macromolecules degraded by Cu(II) ions and ascorbate was examined to produce reactive oxygen species (ROS). Further, the effects of glutathione (GSH), chitosan and its derivatives, added individually or in combination, on the quenching of ROS and ABTS^˙+ cation radical were examined using rotational viscometry and ABTS assay, respectively. The results of the rotational viscometry indicated a rapid degradation of HA by ROS after the addition of acetic acid. Chitosan and its derivatives moderately decreased the rate of HA degradation, while GSH decreased the rate of HA degradation more significantly. Moreover, GSH enhanced the protection of HA macromolecules against their degradation in the presence of chitosan or its derivatives. The results of the ABTS assay confirmed the results of the rotational viscometry. The GSH in the combination with chitosan and its derivatives reduced ABTS^˙+ more intensively than when added individually.     

Soil respiration rates and δ13C(CO2) in natural beech forest (Fagus sylvatica L.) in relation to stand structure

Soil respiration rates were studied as a function of soil type, texture and light intensity at five selected natural beech forest stands with contrasting geology: stands on silicate bedrock at Kladje and Bricka in Pohorje, a stand on quartz sandstone at Vrhovo and two stands on a carbonate bedrock in the Karstic-Dinaric area in Kocevski Rog, Snezna jama and Rajhenav, Slovenia, during the growing season in 2005-2006. Soil respiration exhibited pronounced seasonal and spatial variations in the studied forest ecosystem plots. The CO(2) flux rates ranged from minimum averages of 2.3?μmol CO(2) m(-2) s(-1) (winter) to maximum averages of about 7?μmol CO(2) m(-2) s(-1) (summer) at all the investigated locations. An empirical model describing the relationship between soil respiration and soil temperature predicted seasonal variations in soil respiration reasonably well during 2006. Nevertheless, there were also some indications that soil moisture in relation to soil texture could influence the soil CO(2) efflux rates in both sampling seasons. It was shown that spatial variability of mean soil respiration at the investigated sites was high and strongly related to root biomass. Based on the [image omitted] data, it was shown that new photoassimilates could account for a major part of the total soil respiration under canopy conditions in forest ecosystems where no carbonate rocks are present, indicating that microbial respiration could not always dominate bulk soil CO(2) fluxes. At Snezna jama and Rajhenav, the abiotic CO(2) derived from carbonate dissolution had a pronounced influence on CO(2) efflux accounting, on average, to ～17%. Further spatial heterogeneity of soil respiration was clearly affected by management practice. Higher respiration rates as well as higher variability in respiration rates were observed in the virgin forest (Rajhenav) than in the management forest (Snezna jama) and could be related to a higher amount of detritus and consequently to less pronounced influence of inorganic pool to CO(2) efflux, lower mixing with atmospheric CO(2) and higher sensitivity to environmental changes. Major differences in soil carbon dynamics among these five forest ecosystems can be explained by the influence of bedrock geology (particularly, the presence or absence of carbonate minerals) and soil texture (affecting gas exchange with overlying air and soil moisture).     

Pump Effect of a Capillary Discharge in Electrically Conductive Liquids

Among the configurations to generate plasma in electrically conductive liquids only the diaphragm and the capillary discharge schemes allow to generate plasma which is not in contact with one of the electrodes. Based on this concept, this work reports for the first time the development of an underwater plasma pump, in which the periodic electrical breakdown inside an asymmetrical (sub-)millimetre hole results in a net flow of aqueous solution through the hole without the use of any moving parts such as valves or diaphragms typically used in micropumps. Certain capillary geometries feature very stable flow rates and even allow altering flow direction by changing the power. By varying the hole’s dimensions, the range of time-independent flow rates covers more than one order of magnitude and as the discharge produces some of the strongest oxidants available, we believe that this concept might find application in fields as water decontamination and sterilization.     

The modality principle and work-relativity of modality

Davies argues that the ontology of artworks as performances offers a principled way of explaining work-relativity of modality. Object oriented contextualist ontologies of art (Levinson) cannot adequately address the problem of work-relativity of modal properties because they understand looseness in what counts as the same context as a view that slight differences in the work-constitutive features of provenance are work-relative. I argue that it is more in the spirit of contextualism to understand looseness as context-dependent. This points to the general problem—the context of appreciation is not robust enough to ground modal intuitions about objective entities. In general, when epistemology dictates ontology there is always a threat of anti-realism, scepticism and relativism. Davies also appeals to the modality principle—an entity’s essential properties are all and only its constitutive properties. Davies understands essentiality in a traditional way: a property P is an essential property of an object o iff o could not exist and lack P. Kit Fine has recently made a convincing case for the view that the notion of essence is not to be understood in modal terms. I explore some of the implications of this view for Davies’ modal argument for the performance theory.     

Cyclic edge-cuts in fullerene graphs

In this paper, we study cyclic edge-cuts in fullerene graphs. First, we show that the cyclic edge-cuts of a fullerene graph can be constructed from its trivial cyclic 5- and 6-edge-cuts using three basic operations. This result immediatelly implies the fact that fullerene graphs are cyclically 5-edge-connected. Next, we characterize a class of nanotubes as the only fullerene graphs with non-trivial cyclic 5-edge-cuts. A similar result is also given for cyclic 6-edge-cuts of fullerene graphs.