Sliding a body on snow

Snow is considered as an ideal nonlinear elastoplastic medium. A body performs planeparallel motion on snow. The area of its contact with snow is a part of a rectangular plate. The contact zone changes during the motion of the body. Steady motions are found from the derived equations of motion in the case when the constant external forces and the moment exerted on the body are given. The inverse problem of determining the forces and moments is solved for a given steady motion of a vehicle.     

Microparticles based on chitosan–hyaluronic acid interpolyelectrolyte complex,which provide stability of aqueous dispersions

Turbidimetric titration and laser scattering methods were used to assess the phase behavior of mixtures of chitosan and hyaluronic acid in aqueous solutions in relation to interaction conditions. Conditions were found in which stable water dispersions with particle size of up to 573 nm can be obtained. It was found that the molar ratios and the overall concentration mode of the starting-polyelectrolyte solutions affect the particle size.     

New microbial-friendly polyaniline nanoparticles on the base of nitrilotriacetic acid: comparison with PANI prepared by standard techniques

This paper describes the influence of polyaniline (PANI) nanoparticles prepared in the presence of the nitrilotriacetic acid (NTA) in comparison with PANI prepared by standard techniques, on mixed microbial cultures in the form of a biological extract from soil and activated sludge and partially digested sludge, both sourced from a municipal wastewater treatment plant. The presence of PANI prepared by standard techniques in aqueous environment has a negative effect on the activity of mixed microbial cultures in the form of activated sludge, digested sludge (anaerobic conditions), and natural soil. According to biological oxygen demand (BOD) values—respirometric test, the slight inhibiting effect of nanoparticles is attributed to impurities and oligomers from aniline polymerization. The use of NTA in the production of PANI, resulted in nanotubes with channels through which NTA is incorporated into the structure. A sample thus obtained shows higher values of BOD, which is associated with the fact that NTA is released from PANI nanotube channels followed by its biodegradation.     

Trapping the δ Isomer of the Polyoxometalate‐Based Keggin Cluster with a Tripodal Ligand

We report the synthesis, structural, and electronic characterization of the theoretically predicted, but experimentally elusive δ‐isomer of the Keggin polyoxometalate polyanion. A family of δ‐Keggin polyoxoanions of the general formula, (TEA)H_pNa_q [H₂M₁₂(XO₄)O₃₃(TEA)]?r H₂O where p, q, r=[2,3,8] for 1 and [4,1,4] for 2 were isolated by the reaction of tungstate(VI) and vanadium(V) with triethanolammonium ions (TEAH), acting as a tripodal ligand grafted to the surface of the cluster thereby stabilizing the polyanionic δ‐Keggin archetype. The δ‐Keggin species were characterized by single‐crystal X‐ray diffraction, FT‐IR, UV/Vis, NMR, and ESI‐MS spectrometry. Electronic structure and structure–stability correlations were evaluated by means of DFT calculations. The compounds exhibited multi‐electron transfer and reversible photochromic properties by undergoing single‐crystal‐to‐single‐crystal (SC–SC) transformations accompanied with color changes under light.     

Pulsed X-Ray and Cathodoluminescence of Pure and Alloyed Zinc Selenide Single Crystals

Russian Physics Journal - The paper studies the amplitude and spectral-kinetic behavior of pulsed X-ray and cathodoluminescence of non-alloyed zinc selenide (ZnSe) single crystals and those alloyed...     

Oxidative C–O coupling as a new idea in the ‘click-like chemistry’: malonyl peroxides for the conjugation of two molecules

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