Oxidative fluorination of iridium metal for urban mining: Kinetic studies

AbstractThe process of oxidative fluorination of a compact iridium metal has been studied. For this purpose, tetrafluoridobromates(III) of alkali and alkaline-earth metals were chosen as oxidizing agents with numerous advantages. The main results of this work include the kinetic dependencies for the two following processes: 1) interaction of iridium with molten potassium tetrafluoridobromate; and 2) interaction of iridium with a solution of potassium tetrafluoridobromate in liquid bromine trifluoride. In both cases it has been found out that iridium can be transformed into its soluble fluorinated derivative; the reaction with molten potassium tetrafluoridobromate proceeds almost 50 times faster (in comparison to the interaction in BrF3 solution) and can be potentially applied for the practical purposes

Capillary transport in particulate porous media at low levels of saturation

We have established previously, that the spreading of liquids in granular porous media at low levels of saturation, typically less than 10% of the available void space, has very distinctive features in comparison to that at higher saturation levels. In particular, we showed that the spreading is controlled by a special type of diffusional process, that its physics can be captured by an equation of the super-fast diffusion class, and these findings were supported by first-of-a-kind experiments. In this paper, we take these findings to the next level including deeper examination and exposition of the theory, an expanded set of experiments to address scaling properties, and systematic evaluations of the predictive performance against these experimental data, keeping in mind also potential practical applications

Downstream and soaring interfaces and vortices in 2-D stratified wakes and their impact on transport of contaminants

The flow of continuously stratified fluids past obstacles was studied analytically, numerically, and experimentally. The obstacles discussed here include a flat strip, aligned with the flow, inclined or transverse to the flow and a horizontal cylinder. In the flow pattern, transient and attached (lee) internal waves, downstream wakes with submerged interfaces and vortices, soaring singular interfaces, soaring vortices and vortex systems are distinguished. New components of laminar flow past a horizontally towed strip are presented. Fine transverse streaky structures on the strip in the downstream wake were visualized. Soaring isolated interfaces, which are internal boundary layers forming inside the downstream attached wave field past bluff bodies were observed. With increasing of the body velocity a vortex pair was formed directly at the leading edge of this interface

Geostrophic adjustement of density fronts: what do we learn from recent laboratory experiments ?

We present here a rapid review on recent laboratory investigations on geostrophic adjustment of density fronts. Several configurations were studied: warm core lens, cyclonic-anticyclonic PV patches and uniform PV front. The geostrophic adjustment is the first dynamical process which converts a significant fraction of the potential energy input of the atmosphere and the ocean into kinetic energy. According to the cases we studied we have shown that during this rapid adjustment toward a quasi-equilibrium state, an important part of the initial energy could be transferred to wave motion or dissipated by small-scale non-hydrostatic instabilities. A mean adjusted state is always reached after one or two inertial period. Even if a strong wave activity is present in the initial region of unbalance, the time-averaged mean flow could nevertheless be adjusted. We have shown that the wave modes frequency is concentrated around the inertial frequency. Besides, some anticyclonic structures may also exhibit sub-inertial o

Mobile app as a tool to collect health data: a survey on vaccination against COVID-19

Objective. To evaluate the feasibility of using a mobile app to collect health-related data and the impact of this data collection method on the results obtained, using the COVID-19 vaccination attitude assessment as an example. Material and methods. A survey was conducted on attitudes towards COVID-19 vaccination using the «Know Your Heart» mobile app. A total of 1,770 Arkhangelsk region residents aged 35—74 years who participated in the ЭССЕ-РФ3 survey conducted in the Arkhangelsk region in 2021 were invited to install the application and take part in the survey. Multiple logistic regression analysis was used to evaluate factors related to application installation and survey participation. Results. Of the total number of subjects invited to participate in the study, 611 (34.5%) installed the mobile app, and 150 (8.5%) participated in the survey. Subjects under 65 were more likely to install the application than those 65—74, as were subjects with a steady job versus those without one. Subjects under 65 years of age showed a higher responding rate to the invitation to participate in the mobile survey. Individuals who abused alcohol were less likely to agree to participate in the mobile survey. The majority of respondents are vaccinated against COVID-19 (81%). Vaccinated subjects and those confident in the effectiveness of nonspecific preventive measures were more likely to have positive attitudes towards vaccination. Conclusion. The low response rate to the survey resulting in an unrepresentative sample determined the low effectiveness of the survey using the mobile app. When overcoming these obstacles, mobile applications have the potential to be used in scientific research due to their high speed, accessibility, and ease of data collection

Fenntartható fluoros kémia = Sustainable fluorous chemistry

(1) A „zöldebb” fluoros kémia kialakítása érdekében számos trifluormetil-csoportban gazdag reagens hatékony szintézisét dolgoztuk ki, melyek könnyen hozzáférhető szerves fluorvegyületek hasznosítására és várhatóan nagyobb környezeti lebomlási készségére hívják fel a figyelmet. (2) Eljárásokat dolgoztunk ki 3-perfluoralkil-propanol és 3-perfluoralkil-propén típusú intermedierek előállítására, illetve a köztitermékként megjelenő ún. jódhidrinek sokoldalú preparatív átalakítására. (3) Új típusú fluoros ionos folyadékokat, imidazólium-sókat és más intermediereket állítottunk elő. (4) Orosz fejlesztésű kompozit anyagokat (FUKM, FUKM-M és FUKM-MT) kémiai reagensként, illetve átmenetifém katalizátor (Pd/FUKM) hordozóként alkalmaztunk. (5) Tanulmányoztuk a Hiyama- és a Heck-kapcsolási reakciók mechanizmusát és szintetikus alkalmazhatóságát. (6) CF3I reagnest S-alkilezőszerként alkalmaztuk (7) Prof. Bühlmann al együttműködve fluoros ionofórokat és elektrokémiai szenzorokat készítettünk. (8) Azonosítottuk egy új potenciális fluorátvivő reagens molekulaszerkezeti feltételeit, melynek segítségével lehetőségünk nyílik a fluoros kémiából (fluortartalmú modulok) a fluorkémiába (szén-fluor kötesek kialakítása) átlépnünk. Ez lehetőséget ad a gyógyszerkémia számára fontos egy, kettő, vagy három fluoratomot tartalmazó vegyületek hatékony előállításához. Több közlemény csak a kövtekező évben fog megjelenni, kérem az értékelésnél ezt vegyék figyelembe. | (1) For Greener Fluorous Chemistry we developed the synthesis of several reagents from easily accessible precursor, reach in CF3-goups, which expected to have less impact and shorter environmental half-lives. (2) Novel methods for the synthesis of 3-perfluoroalkyl-propanols and –propenes were disclosed along with the uses of their synthetic intermediates. (3) New types of fluorous ionic liquids were synthesised based on imidazolium-salts. (4) Carbon-fluorinated carbon composite materials of Russian origin were applied as chemical reagents and transition metal catalyst support material (e.g. Pd/FUKM) . (5) Hiyama- and Heck-reactions with fluorous substrates were studied for a synthetic and mechanistic point of view. (6) Trifluoroiodomethane was used for improved S-alkylating processes. (7) Fluorous ionophores and electrochemical sensors were designed for the first time in co-operation with Prof. Bühlmann. (8) The structural requirements for a potential new fluorine-transfer reagent were identified and a Patentable process designed. This will allow the introduction of one, two or three fluorine atoms into target pharmaceutical molecules, and allow a shift from the fluorous to the fluorine chemistry (i.e. from F-building blocks to create C-F bonds). Please consider that some more publications are expected to appear only in the next year

Capillary transport in paper porous materials at low saturation levels: normal, fast or superfast?

The problem of capillary transport in fibrous porous materials at low levels of liquid saturation has been addressed. It has been demonstrated, that the process of liquid spreading in this type of porous materials at low saturation can be described macroscopically by a similar super-fast, non-linear diffusion model as that, which had been previously identified in experiments and simulations in particulate porous media. The macroscopic diffusion model has been underpinned by simulations using a microscopic network model. The theoretical results have been qualitatively compared with available experimental observations within the witness card technique using persistent liquids. The long-term evolution of the wetting spots was found to be truly universal and fully in line with the mathematical model developed. The result has important repercussions on the witness card technique used in field measurements of dissemination of various low volatile agents in imposing severe restrictions on collecting and measurement times