2 research outputs found
Features of the surface layer structure of the magnetosensitive materials functionalized by silica with thiourea groups and their applying for selective Cu(II) and Au(III) ions removal
One-step sol-gel synthesis for covering magnetic particles with polysiloxane layers with equivalent to Si(CH2)3NHC(S) NHC2H5 groups has been proposed. Unique properties of this functional group, containing sulfur and nitrogen, and the developed approach open wide (and novel) opportunities for the controlled surface design. A number of factors affecting the characteristics of such materials and their sorption properties towards heavy metal ions were analyzed. Results of scanning and transmission electron microscopy studies, Fourier-transform infrared spec-troscopy, nitrogen adsorption-desorption measurements, elemental analysis, thermogravimetric analysis, and X-ray powder diffraction analysis indicated that, depending on the ratio of core/shell components, the resulting spherical moieties with size of 35.1-43.1 nm, can form agglomerates of larger sizes. Packing of these aggregates offers porosity to such materials, having a dense or loose polysiloxane shell, with thiourea groups load of 0.67-1.05 mmol/g. The synthesized materials proved to be effective in extraction of Cu(II), Pb(II), Cd(II), Hg(II), Ag(I), Au(III), Zn(II) ions from aqueous solutions, as well as in selectively adsorption of Au(III) ions at pH = 3 and Cu(II) ions at pH = 5.5. X-ray photoelectron spectroscopy demonstrated different types of interactions between metal ions and the thiourea groups, depending on pH
Interpretacja geometryczna zr贸偶nicowania typ贸w ska艂 w przestrzeni Hilberta
Signal of vibrations accompanying the rotary drilling of three rock types (andesite, limestone and granite) by diamond core-drill bits was processed and evaluated in order to track the signal characteristics of tested rock types. Mathematical procedures of Hilbert鈥檚 abstract space were applied to express the differences between the rock types based on vibration signal. Experiments were performed using the laboratory drilling rig designed and constructed at the Institute of Geotechnics SAS providing automated continuous monitoring of key process parameters (thrust force, rotation speed, torque, advance rate, etc.). Nominal regime of thrust force 5000 N and rotation speed 1000 rpm was used in the experiments along with monitoring with sampling frequency 17 kHz. The vibration signal was recorded by accelerometers in three orthogonal directions: axial in the drilling directions and two radial directions in horizontal and vertical planes. For the purposes of evaluation, only the vibrations in axial direction were assessed as their signal exhibits the highest entropy. A method providing the expression of mutual differences between the vibrations formed during the drilling of different rock types was developed, which enables to set the differences in abstract space to the planar visualization.Sygna艂y drga艅 pochodz膮cych z wierceniu obrotowego trzech rodzaj贸w ska艂 (andezyt, wapie艅 i granit) za pomoc膮 diamentowych wierte艂 rdzeniowych zosta艂 przetworzony i oceniony w celu 艣ledzenia charakterystyk sygna艂owych badanych rodzaj贸w ska艂. Zastosowano matematyczne procedury przestrzeni Hilberta, aby wyrazi膰 r贸偶nice mi臋dzy rodzajami ska艂 w oparciu o sygna艂 wibracyjny. Eksperymenty przeprowadzono na laboratoryjnej platformie wiertniczej zaprojektowanej i skonstruowanej w Instytucie Geotechniki SAS, zapewniaj膮cej zautomatyzowane ci膮g艂e monitorowanie kluczowych parametr贸w procesu (si艂y ci膮gu, pr臋dko艣ci obrotowej, momentu obrotowego, pr臋dko艣ci posuwu itp.). W do艣wiadczeniach zastosowano nominaln膮 warto艣膰 si艂y nacisku 5000 N i pr臋dko艣ci obrotowej 1000 rpm wraz z monitorowaniem cz臋stotliwo艣ci 17 kHz. Sygna艂 drga艅 zosta艂 zarejestrowany przez akcelerometry w trzech kierunkach ortogonalnych: osiowym w kierunkach wiercenia i dw贸ch promieniowych w p艂aszczyznach poziomej i pionowej. Do cel贸w oceny oceniono jedynie drgania w kierunku osiowym, poniewa偶 ich sygna艂 wykazuje najwy偶sz膮 entropi臋. Opracowano metod臋 wyra偶ania wzajemnych r贸偶nic mi臋dzy drganiami powstaj膮cymi podczas wiercenia r贸偶nych rodzaj贸w ska艂, kt贸ra umo偶liwia przeniesienie r贸偶nic z przestrzeni Hilberta na wizualizacj臋 dwuwymiarow膮