Effect of Cr(III) solution chemistry on electrodeposition of chromium

This work provides a new insight into the interaction of urea with formate during the chromium electrodeposition from a sulphate-based Cr(III) solution. The influence of solution chemistry on chromium electrodeposition in a Cr(III) bath containing sodium formate and urea as complexing agents was studied by FT-IR, XPS and AFM. The results show that good quality Cr coatings may be obtained only in those cases when the secondary ligand with the carbamidic group predominates over urea in the electrolyte. This suggests that electrodeposition of good quality chromium deposit is possible due to the formation of active chromium–carbamid complexes [Cr(carbamid)_n(H₂O)_6-n ]³⁺. These complexes delay the formation of the stable oligomeric species, and thus provide a prolonged working lifetime in the Cr(III) formate-urea electrolyte.     

Decontamination of Zincate Solutions Using Calcium Hydroxide in a Fluidised Bed Reactor

This article deals with the decontamination and utilisation of waste water. The effectiveness and conditions for the removal of Zn(II) from diluted alkali zinc electroplating bath solutions in flow-rate regime have been investigated. A cheap and simple decontamination route is proposed using the fluidised bed reactor with Ca(OH)₂. The advantage of this method is that up to 98% of Zn(II) can be precipitated as a fine crystalline recyclable material—CaZn₂ (OH) ₆ 2H₂O with small amount of ZnO. The industrial scheme of this process using lime is proposed.     

Selective Dissolution of Electrodeposited Zn-Ni Alloy Coatings

The corrosion of Zn-Ni alloy coatings in pure and NaHCO, containing Nad solutions was investigated under open circuit potential conditions. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) techniques were applied for the alloy surface characterisation, while direct current plasma emission spectrometry was used for test solution and corrosion product film analysis. It has been established that Zn dissolves preferentially leaving a top layer slightly enriched with Ni. However, this layer does not act as a barrier layer for the further corrosion attack. The presence of NaHCO₃, in NaC! solution causes a reduction in the corrosion rales of Zn-Ni alloy and the thickness of corrosion product (oxide) film, as well as affecting the ratio of the soluble and insoluble fractions of ionised Zn and Ni and the development of the surface morphology. In a pure NaCl solution Zn-Ni corrosion occurred with surface roughening, while in the presence of NaHCO₃ the process was accompanied by surface smoothing.     

Menstrual Blood-Derived Endometrial Stem Cells’ Impact for the Treatment Perspective of Female Infertility

When looking for the causes and treatments of infertility, much attention is paid to one of the reproductive tissues—the endometrium. Therefore, endometrial stem cells are an attractive target for infertility studies in women of unexplained origin. Menstrual blood stem cells (MenSCs) are morphologically and functionally similar to cells derived directly from the endometrium; with dual expression of mesenchymal and embryonic cell markers, they proliferate and regenerate better than bone marrow mesenchymal stem cells. In addition, menstrual blood stem cells are extracted in a non-invasive and painless manner. In our study, we analyzed the characteristics and the potential for decidualization of menstrual blood stem cells isolated from healthy volunteers and women diagnosed with infertility. We demonstrated that MenSCs express CD44, CD166, CD16, CD15, BMSC, CD56, CD13 and HLA-ABC surface markers, have proliferative properties, and after induction of menstrual stem cell differentiation into epithelial direction, expression of genes related to decidualization (PRL, ESR, IGFBP and FOXO1) and angiogenesis (HIF1, VEGFR2 and VEGFR3) increased. Additionally, the p53, p21, H3K27me3 and HyperAcH4 proteins’ expression increased during MenSCs decidualization, they secrete proteins that are involved in the regulation of the actin cytoskeleton, estrogen and relaxin signaling pathways and the management of inflammatory processes. Our findings reveal the potential use of MenSCs for the treatment of reproductive disorders.     

Fiber-shaped Co modified with Au and Pt crystallites for enhanced hydrogen generation from sodium borohydride

This work presents the study of catalytic activity of the fiber-shaped Co decorated with low amounts of Au or Pt nanoparticles for the hydrolysis of sodium borohydride in alkaline conditions. The morphology, structure and composition of the prepared catalysts were examined using Field Emission Scanning Electron Microscopy, Energy Dispersive X-ray Analysis and Inductively Coupled Plasma Optical Emission Spectroscopy.It was found that the decoration of the fiber-shaped Co with the Au or Pt nanoparticles allows enhancing of catalytic activity for the hydrolysis of sodium borohydride, compared with that of the pure fiber-shaped Co.     

Determination of the dye penetration rate in porous aluminum oxide using Raman spectroscopy

Oxidised aluminum coatings are useful in various high technology applications to protect surfaces from negative environmental effects. In this study, aluminum discs and foils of industrial alloys were anodised in a sulphuric acid/oxalic acid electrolyte. Scanning electron microscopy was used to determine the pore diameter, distribution and surface porosity. The anodising procedure was adapted to produce near‐hollow templates on aluminium foil, onto which aqueous solutions of commercial chromium‐complexed anionic azodyes were dropped. Raman spectroscopy was used to detect the penetration of dye compounds based on the most intensive vibrational modes. Each dye was successfully monitored to assess its penetration rate and behaviour in the anodised coating. This method could be applied to characterise newly developed organic dyes for aluminum colouring.     

The Concept and RELAP5 Model of Thermal-Hydraulic System,Employing a Rapid Condensation for Coolant Circulation

The rapid condensation event is mostly considered a dangerous and undesirable side effect in thermal-hydraulic systems. This work demonstrates a different viewpoint, where condensation implosion is employed to perform mechanical work. Previous experimental study of the condensation implosion event, briefly presented in this article, showed that condensation implosion can be induced intentionally. These results were used as the basis for further investigations. In this work, a concept of the thermal-hydraulic system has been developed, where condensation-implosions-generated pressure difference could be used as a driving force. Numerical study has been performed to investigate the operation of the developed conceptual thermal-hydraulic system. A thermal-hydraulic computer code RELAP5 was selected for modeling the system operation. The RELAP5 code was found not able to predict the condensation implosion; therefore, a modified heat transfer model was implemented into the code. This modification allowed simulating the condensation implosion artificially in the thermal-hydraulic system and modeling the system response to the event. Final results show that a proposed circulation principle is possible and such a thermal-hydraulic system can operate.     

UV-NIL replication of microlens arrays on flexible fluoropolymer substrates

Microsystem Technologies - This paper describes application of UV-NIL technique for the fabrication of hexagonal OrmoComp microlens arrays on flexible fluoropolymer substrates having exceptional...