Desulphurization of damped battery paste by sodium carbonate and sodium hydroxide

The paper treats investigation of the desulphurization process of damped Pb-paste by Na₂CO₃ or NaOH. There is determined the effect of Na₂CO₃ (NaOH) concentration and the liquid–solid phase ratio on the process parameters (degree of desulphurization and degree of Na₂CO₃ (NaOH) utilization in function of the temperature and process duration). The optimum conditions for carrying out desulphurization of Pb-pastes by Na₂CO₃ or NaOH are determined in dependence of the used reactors (common reactor with laboratory agitator and rotary reactor of drum type). The content of inclusions in the solutions is examined with the purpose of producing sufficiently pure crystalline Na₂SO₄ for the industry.     

GeD spline estimation of multivariate Archimedean copulas

A new multivariate Archimedean copula estimation method is proposed in a non-parametric setting. The method uses the so-called Geometrically Designed splines (GeD splines) to represent the cdf of a random variable W_θ, obtained through the probability integral transform of an Archimedean copula with parameter θ. Sufficient conditions for the GeD spline estimator to possess the properties of the underlying theoretical cdf, K(θ,t), of W_θ, are given. The latter conditions allow for defining a three-step estimation procedure for solving the resulting non-linear regression problem with linear inequality constraints. In the proposed procedure, finding the number and location of the knots and the coefficients of the unconstrained GeD spline estimator and solving the constraint least-squares optimisation problem are separated. Thus, the resulting spline estimator is used to recover the generator and the related Archimedean copula by solving an ordinary differential equation. The proposed method is truly multivariate, it brings about numerical efficiency and as a result can be applied with large volumes of data and for dimensions d≥2, as illustrated by the numerical examples presented.     

A comparison of two different methods for formation of the beta phase in nanocomposites based on vinylidene fluoride-hexafluoropropylene copolymer

Nanocomposite materials based on vinylidene fluoride-hexafluoropropylene copolymer and organically modified montmorillonite Cloisite®15A were prepared by two different methods: melt mixing and co-precipitation. The changes taking place in crystalline structure, tensile strength, thermal behavior and the formation of piezoelectric b-phase as a result of the polymer system dissolution in dimethyl sulfoxide were studied. The technological specificity of each method has certain effect on the properties of the obtained nanocomposites. The highest content of b-phase — 95 % was achieved by co-precipitation from the solution of vinylidene fluoride-hexafluoropropylene copolymer in dimethyl sulfoxide and 6 mass % content of Cloisite®15A. Despite the common view that the use of solvents and prolonged technological procedure lead to overall higher expenses, the obtained nanocomposites could be promising for the preparation of new piezo-materials.     

Single-Walled Carbon Nanotubes Modify Leaf Micromorphology,Chloroplast Ultrastructure and Photosynthetic Activity of Pea Plants

Single-walled carbon nanotubes (SWCNTs) emerge as promising novel carbon-based nanoparticles for use in biomedicine, pharmacology and precision agriculture. They were shown to penetrate cell walls and membranes and to physically interact and exchange electrons with photosynthetic complexes in vitro. Here, for the first time, we studied the concentration-dependent effect of foliar application of copolymer-grafted SWCNTs on the structural and functional characteristics of intact pea plants. The lowest used concentration of 10 mg L⁻¹ did not cause any harmful effects on the studied leaf characteristics, while abundant epicuticular wax generation on both leaf surfaces was observed after 300 mg L⁻¹ treatment. Swelling of both the granal and the stromal regions of thylakoid membranes was detected after application of 100 mg L⁻¹ and was most pronounced after 300 mg L⁻¹. Higher SWCNT doses lead to impaired photosynthesis in terms of lower proton motive force generation, slower generation of non-photochemical quenching and reduced zeaxanthin content; however, the photosystem II function was largely preserved. Our results clearly indicate that SWCNTs affect the photosynthetic apparatus in a concentration-dependent manner. Low doses (10 mg L⁻¹) of SWCNTs appear to be a safe suitable object for future development of nanocarriers for substances that are beneficial for plant growth.     

Special Theme: Project Management in E-Science: Challenges and Opportunities

In this introduction to the special theme: Project Management in e-Science: Challenges and Opportunities, we argue that the role of project management and different forms of leadership and facilitation can influence significantly the nature of cooperation and its outcomes and deserves further research attention. The quality of social interactions such as communication, cooperation, and coordination, have emerged as key factors in developing and deploying e-science infrastructures and applications supporting large-scale and distributed collaborative scientific research. If software is seen to embody the relational web within which it evolves, and if the processes of software design, development and deployment are seen as ongoing transformations of this dynamic web of relationships between technology, people and environment, the role of managers becomes crucial: it is their responsibility to balance and facilitate the dynamics of these relationships.     

Artisanal cheeses relying on spontaneous fermentation as sources of unusual microbiota – The example of the Bulgarian ‘mehovo sirene’ skin bag cheese

The Bulgarian ‘mehovo sirene’ cheese is a type of regional artisanal cheese prepared from raw ewe milk in a skin bag relying on spontaneous fermentation. A metagenomics study revealed an unusual microbiome comprising beneficial bacteria such as Staphylococcus equorum, Lactococcus lactis, Streptococcus thermophilus, Lactobacillus delbrueckii, Lactobacillus kefiranofaciens, Lactococcus raffinolactis, Lactiplantibacillus plantarum, Limosilactobacillus fermentum and Loigolactobacillus coryniformis. Our findings suggest that ‘mehovo sirene’ could have some functional food properties and is a source of beneficial microorganisms.