Dissolving grade eco-clean cellulose pulps by integrated fractionation of cardoon (Cynara cardunculus L.) stalk biomass

A biorefinery scheme with separate processing of the two main carbohydrate streams (cellulose and hemicellulose-derived) was employed to the energy crop cardoon (Cynara cardunculus L.) to fractionate the whole stalk material. A high quality xylose-enriched substrate was obtained after selective one-step dilute sulfuric acid hydrolysis of hemicelluloses, yielding 18.1 g of xylose per 100 g of dry biomass. The xylan-free solid residue was delignified by sulfur-free organosolv pulping to produce dissolving grade pulps having 93.8% of α-cellulose (33.1 g per 100 g dry initial biomass) and 79.5% degree of crystallinity. About 76% of crop lignin (13.8 g per 100 g dry initial biomass) was recovered from the spent pulping liquor as a high purity reactive precipitated organosolv lignin. Response surface methodology was used for statistical modeling and optimization of the applied separation processes. The central composite rotatable design was applied to assess the effects of the principal technological parameters on the main reaction outputs.     

DNA-based materials as chemical reactors for synthesis of metal nanoparticles

In this minireview we highlight a recent progress in preparation of DNA-based matrices that can be used as reactors for templating of inorganic nanomaterials and, in particular, highlight catalytic applications of such hybrid materials. We also discuss advantages and disadvantages of DNA utilization as a material and outline prospects of DNA-based technologies in future.     

Conversion of brown coal in supercritical water without and with addition of oxygen at continuous supply of coal-water slurry

A study of conversion of organic matter of brown coal in supercritical water (SCW) at 30 MPa, 400−760 °C and continuous supply of coal-water slurry (CWS) into a tubular reactor is presented. It was found that 48−63% (depending on the SCW temperature) of coal organic matter (COM) is ejected from CWS coal particles as liquid and gaseous products when they move through the reactor. We termed this stage of SCW conversion as dynamic conversion (DC) of coal. It turns out that the particles which underwent the DC stage did not aggregate in the reactor during static conversion (SC) within a coal layer due to continuous pumping through this layer. The experimental data on the composition of DC and SC products, degree of coal conversion, and the data on the degree of combustion of carbon in the presence of oxygen are given.     

Gd-Bi-M-Ce-O (M = Cu,Zr, Ni,Co, Mn) ceria-based solid solutions for low temperature CO oxidation

Ceria based solid solutions doped by Gd, Bi, and the third dopant were synthesized by the co-precipitation method with ultrasonic treatment, followed by calcination at the temperature of 500°С. Characterization of the synthesized nanosystems by XRD, TEM, TG, Raman spectroscopy, FTIR, XPS was carried out. It is shown that all obtained powders of solid solutions crystallized into a cubic structure of the fluorite type, with an average particle size of 5–15 nm. The samples had a mesoporous structure of the pore diameter of 2–5 nm. The catalytic activity of Gd-Bi-M-Ce-O (M = Cu, Zr, Ni, Co, Mn) solid solutions was carried out. The catalyst Gd_0.05Bi_0.15Mn_0.20Ce_0.60O₂ has the lowest oxidation temperature.     

Polyphenols Fingerprinting in Olive Oils Through Maximum-Quantum NMR Spectroscopy

An NMR protocol based on multiple-quantum spectroscopy is presented for an analytical screening of polyphenols in olive oils. Three Italian olive oils with different total polyphenols content were used as study case. A total of 24 compounds were identified as follows: 1 polyphenol in the 5Q–1Q, 15 more in the 4Q–1Q, and 8 components in the 3Q–1Q spectra, consisting of organic phenols, secoiridoids, lignans, and flavonols. In the three Italian olive oils investigated here, the polyphenols profile turned out to be significantly different, with specific characteristics going beyond simple considerations based on the total polyphenol content. The approach presented here can be easily extended for rapid qualitative and semi-quantitative screening of the polyphenol composition in many food products.     

Photochemical modulation of DNA conformation by organic dications

A group of azobenzene derivatives containing two quaternary ammonium groups with various intercharge distances between them was synthesised and used to control photochemically the conformation of genomic DNA by switching the distance between cationic ammonium groups in the dications. It was found that isomerisation of either dication from the trans form to cis resulted in an increase in the dication's efficiency for DNA compaction; this is associated with a decrease in intercharge distance between ammonium groups and leads to a better match of the binder's cationic groups to adjacent phosphate groups of DNA. Ammonium dications have several important advantages over the photosensitive surfactant type of diazobenzene reported earlier: they can be used at significantly lower (>100-fold) concentrations than photosensitive surfactants, and DNA conformation control can be performed over a broader concentration range of dications. The influence of intercharge distance in photosensitive dications on photo-induced DNA binding discrimination is discussed, and the molecular mechanism is proposed.     

Redundancy analysis for repairable multi-state system by using combined stochastic processes methods and universal generating function technique

This paper discusses a type of redundancy that is typical in a multi-state system. It considers two interconnected multi-state systems where one multi-state system can satisfy its own stochastic demand and also can provide abundant resource (performance) to another system in order to improve the assisted system reliability. Traditional methods are usually not effective enough for reliability analysis for such multi-state systems because of the “dimensional curse” problem. This paper presents a new method for reliability evaluation for the repairable multi-state system considering such kind of redundancy. The proposed method is based on the combination of the universal generating function technique and random processes methods. The numerical example is presented to illustrate the proposed method.     

Fischer–Tropsch synthesis using plug-through contactor membranes based on permeable composite monoliths. Selectivity control by porous structure parameters and membrane geometry

The Fischer–Tropsch synthesis using a contactor membrane reactor was studied varying pore size distribution parameters and membrane geometry. These parameters are responsible for the magnitude of the diffusion constrains and, therefore, correlate with the FTS process productivity and selectivity. The nature of the observed correlations is discussed.     

Possibilities for hypervelocity impact experiments in frames of demonstration project “Space Patrol”

It is proposed to reach impact velocity of macrobodies up to 90 km/s by collision of space probe with celestial bodies in meteor flux. Results of the approach dynamics and targeting simulation shows feasibility of this idea. Science experiments and registration method, based on measuring electromagnetic fields, inducing during the impact, are proposed. It is shown, on the basis of an impact experiment of the small mass body, that it is possible to determine parameters of asteroids such as dynamic strength, crack resistance etc.