This paper presents a comprehensive classification of test protocols for electrochemical hydrogen pumps (EHPs) used in hydrogen extraction and compression processes. The proposed classification serves as a practical guide for selecting protocols for specific process applications. Experiments were conducted at temperatures ranging from 20 to 70 degrees C and anode pressures ranging from 0.01 to 0.1 MPa using humidified H-2/He mixtures. EHP performance was compared under identical conditions in flux, stationary (dead-end), and recirculation modes. The flux mode provides the highest performance vs the highest degree of extraction in the stationary mode. The recirculation mode combines these advantages as the final stage of an H-2-extraction cascade. In recirculation mode the current density reduction is only 27% for pure H-2 and 31% for mixtures at 70 degrees C and 0.9 V. Recirculation also reduces extraction time from 74 to 17 min, while maintaining a recovery rate of 91%.
Yttrium aluminum garnet (YAG) nanopowders were synthesized via novel sol-gel route assisted by supercritical carbon dioxide (CO2) drying. For samples calcined at 850 °C Scherrer crystallite size was 35 nm and the average particle size was 53 nm.
The intrinsic antimicrobial activity of personal care products against the sweat odor is a necessary element of their functional properties. To estimate this characteristic, two bacterial strains typical for the armpit zone were selected as test organisms: Corynebacterium stationis VKPM-V-10645 and Micrococcus luteus VKPM-V-7845 that demonstrated a sensitivity to all tested commercial deodorant/antiperspirant samples. An express method (a method of “rapid” microbiology) using a 0.03
This paper provides experimental justification for selecting cement-based materials for engineered safety barriers (ESB) in geological disposal facilities (GDF) for radioactive waste. The long-term performance of three materials — Ordinary Portland Cement Concrete (OPCC), Calcium Aluminate Cement Concrete (CACC), and Nirex Reference Vault Backfill (NRVB) —was comparatively analyzed under conditions simulating groundwater impact in a crystalline rock massif. A one-year filtration experiment was conducted using synthetic groundwater at elevated pressure. The evaluation included comprehensive assessment of phase composition evolution, mechanical strength, hydraulic permeability, and chemical/electrochemical parameters of the interacting liquid phase. Results demonstrated that OPCC maintained increased content of strengthening phases (C-S-H, ettringite), enhanced mechanical strength exceeding the required minimum of 7.5 MPa, and consistently low hydraulic permeability (~10 -12 m/s), meeting ESB criteria for contact with bentonite buffer. The pH of its filtrate remained below 11.5, minimizing alkaline degradation risks for bentonite. In contrast, NRVB exhibited complete dissolution of C-S-H and portlandite, resulting in significant strength reduction and high hydraulic permeability, making it unsuitable for bentonite buffer contact. For aluminate concrete, cross-reaction of metastable phase CAH 10 into less dense C 3 AH 6 caused substantial strength decrease and increased hydraulic permeability exceeding maximum permissible values (10 -10 m/s), limiting its GDF application. Based on these findings, Ordinary Portland Cement Concrete emerges as the preferred material for ESB construction in GDF. These results establish foundation for subsequent geochemical modeling of long-term cement barrier evolution.
Molybdenum blue dispersions were synthesized via an ion-exchange approach using hydroquinone and glucose as reducing agents to clarify the influence of reductant chemistry on redox evolution and colloidal stability. Electrolyte-free conditions enabled controlled self-assembly of reduced polyoxomolybdate clusters. UV-Vis spectroscopy revealed characteristic absorption bands at similar to 750 and similar to 1100 nm associated with intervalence charge transfer in mixed-valence Mo5+/Mo6+ clusters, with hydroquinone stabilizing more deeply reduced clusters, while glucose-derived systems demonstrated a higher degree of reduction with a higher ratio of reducing agent to metal. Time dependence of oxidation-reduction potential and optical density measurements demonstrated prolonged redox equilibration and gradual self-organization over several weeks. Dynamic light scattering confirmed the formation of nanoclusters with comparable hydrodynamic diameters of approximately 3.5 nm for both reducing agents. Raman and FT-IR spectroscopy indicated structurally similar polyoxomolybdate frameworks. In contrast, electrokinetic measurements revealed pronounced differences in surface chemistry and stability: hydroquinone-derived dispersions exhibited robust, pH-independent electrostatic stabilization, whereas glucose-derived systems showed weaker, pH-dependent stabilization and rapid electrolyte-induced aggregation. These results demonstrate that the nature of the reducing agent has an impact on the synthesis and colloidal behavior of molybdenum blue dispersions synthesized by the ion-exchange route.
