Zinc-rich paint coatings containing either ionic surfactant-modified or functionalized multi-walled carbon nanotube-supported polypyrrole utilized to protect cold-rolled steel against corrosion

The intense anodic action of sacrificial zinc pigments ensured viable galvanic function of the highly porous liquid zinc-rich paints (ZRPs) result in deteriorated long-term corrosion resistance often accompanied by cathodic delamination phenomena. In our approach, such a efficacy problem related to the corrosion preventive function of ZRPs is addressed by the application of intimately structured anodic inhibitor particles composed of nano-size alumina and either polyelectrolyte-modified or chemically functionalized multi-walled carbon nanotubes (MWCNT) supported polypyrrole (PPy) in one specific zinc-rich hybrid paint formulation providing balanced active–passive protective functionality. High dispersity of the nanotube-free PPy-deposited inhibitor particles (PDIPs) with uneven polymer distribution on the alumina carrier was confirmed by transmission electron microscopy (TEM) observations. Furthermore, the MWCNT-embedded PDIPs indicated almost complete surface coverage of the alumina-nanotube carriers by PPy with decreased microstructure dispersity which is attributed to the effect of double-flocculants type co-deposition of the oppositely charged polymers causing coalescence of the modified particles. Depending on the amount of the nanotubes and their proportion to the quantities of the deposited PPy and polyelectrolyte as well as the concentration of the surfactant, varied micron-scale association of the PDIPs in the suspensions of dissolved alkyd matrix was disclosed by rheology characterization carried out at particular solid contents similar to hybrid paint formulation. The evenly distributed but less densely packed nano-structure of PPy was evidenced on the polyelectrolyte-modified nanotubes by Fourier-transform infrared (FTIR) spectroscopy whereas more compact polymer film formation was confirmed on the surface of functionalized nanotubes. According to the greater electrical conductivity, enhanced electroactivity and reversibility of the nanotube-embedded PDIPs were indicated over the nanotube-free particles by cyclic voltammetry, depending on the type and the amount of the nanotubes and their modification. Protection function of the hybrid paint coatings (formulated with spherical zinc pigment at 70 wt.%) was investigated by immersion and salt-spray chamber tests over 254 and 142 day periods, respectively. Firm barrier nature of the nanotube-embedded PDIP contained hybrids was proved by electrochemical impedance spectroscopy (EIS) and radio-frequency glow-discharge optical-emission-spectroscopy (RF-GD-OES). Furthermore, due to the increased conductivity of the nanotube-embedded PDIPs cemented in epoxy primers optimally at 0.4 and 0.6 wt.%, altered corrosion preventive behaviour of the hybrid coatings was indicated by the positively polarized open-circuit potentials (OCPs) and the X-ray photoelectron spectroscopy (XPS) detected lower relative quantities of the interfacially accumulated zinc corrosion products, moderate oxidative degradation of the epoxy vehicle. Decreasing oxidative conversion of iron at the surface was indicated by XPS found to correlate with the increasing intensity of zinc corrosion and decreasing oxidative degradation of the epoxy binder, according to the higher nanotube contents of hybrid coatings. In addition, inhibited zinc corrosion caused low rate of oxidative degradation of epoxy, allowing increased durability of coating adhesion and cohesion thereby ensuring reliable protection by zinc-rich compositions. As a conclusion, modified or functionalized MWCNTs acting as unexchangeable doping agents promote enhanced reversibility and increased conductivity of PPy, forming nano-size inhibitor particles with advanced features. Thus, such inhibitor nano-particles in zinc-rich hybrid compositions afford improved barrier and high efficiency galvanic–cathodic corrosion preventive function, exceeding long-term protection capability of the conventional ZRPs

High-precision loess chronologies by 14C-dating of small molluscs

Despite that loess records provide a wealth of information on abrupt climatic and environmental changes, almost all such records have low precision chronologies. Age-depth models of loess sequences have uncertainties reaching thousands of years thereby rendering proxy interpretations highly ambiguous on millennial/sub-millennial timescales. This is partly because OSL/IRSL dating techniques, commonly applied to eolian deposits, yield imprecise ages on such timescales. Also, 14C-dating of organic matter, secondary carbonates and humic acids provide questionable and mostly unreliable dates, for reasons not detailed here. At the same time, charcoals that are regarded as phases yielding reliable ages rarely occur in loess sequences and 14C-dates of molluscs are often anomalously old due to dead carbon incorporation during shell formation. Here we show that some species of molluscs having small (≦ 10 mm) shells incorporate very low amounts of 14C-deficient carbon into their shells and provide reliable ages as revealed by testing against charcoal ages and against a Bayesian age-depth model. 56 AMS radiocarbon ages were generated from a loess profile at Dunaszekcso (Hungary). Of these ages four originate from charcoals and are taken as reference. Comparison of mollusc shell ages with those of charcoals reveal that Succinella oblonga and Vitrea crystallina give statistically indistinguishable ages, while Chondrula tridens and Clausilia sp. shells show age anomalies ranging from 500 to 900 14C yr. Testing against a Bayesian age model resting on 48 14C ages at different depths (2-3 ages from each depth), highlights that, beyond S. oblonga and V. crystallina, species like Orcula dolium, Discus ruderatus, Euconulus fulvus, Pupilla muscorum and Vallonia costata yield relatively accurate ages (anomalies mostly within ±300 cal BP yr). This investigation also demonstrates that Trichia hispida is best avoided in 14C-dating studies and that micrographitization of shells, in case of low carbon contents after preparation, always results in anomalous ages

Scaling Hydrodynamical Evolution of a Gravitating Dark-fluid Universe

We present a dark fluid model which contains the general linear equation of state including the gravitation term. The obtained spherical symmetric Euler equation and the continuity equation was investigated with the Sedov-type time-dependent self-similar {\it ansatz} which is capable to describe physically relevant diffusive and dispersive solutions. %The role of the parameter in the equation of state is investigated. As results the space and time dependent fluid density and radial velocity fields are presented and analyzed. Additionally, the role of the initial velocity on the kinetic and total energy densities of the fluid is discussed.Comment: 8 pages and 5 figure

A vállalati foresight helyzete Magyarországon

A tanulmány célja az, hogy bemutassa a vállalati foresight helyzetét Magyarországon egyrészt az előzményei és a létrejötte függvényében, másrészt a szélesebb környezete és a felsőoktatásban elfoglalt helyzete kapcsolatában. Áttekinti a hazai vállalati foresight feltárására irányuló kutatásokat és néhány jó vállalati gyakorlatot is megmutat, valamint azok eredményei alapján foglalja össze a hazai vállalati foresight jelenlegi jellemzőit

Effect of actions supported by the National Game Management Fund according to the hunters in Hungary

Since 2017, grants from the National Game Management Fund have supported the development of the habitats for the game species by providing hiding and feeding places for them and by the effective control of their predators. We evaluated the effects of these management actions on the local wildlife populations with a questionnaire survey among the supported game management units between 2018 and 2020. We asked them about their impressions or measured data regarding the size and quality of the game populations treated during the program. We compared the conditions before and after the interventions, specifying the methods in case of measurements. The 241 answers covered 35% of all the supported game management units. Most applicants (94%) rated their management actions as effective, while only 2% reported the contrary. Game managers collected data to measure the efficiency relatively infrequently (14±9% of the beneficiaries for each variable group in each target area, min-max: 3–44%). Much more often, they relied on non-scientific observations and perceptions (63±14%, min-max: 36–93%). We conclude that it would be necessary to evaluate the efficiency on the basis of systematic data collection and analyses (monitoring), at least with smaller samples at the level of game management units. Game managers should measure the use of the treated areas by the game species and the changes in the quantity and quality of the populations (e.g., camera trapping at drinking and feeding sites, spotlight counts of brown hares, estimating the reproduction, condition or trophy quality indices)

Carbon Isotope Investigation of Freshwater Tufa Precipitation in Karst Streams of Bükk Mountains (Hungary)

Recent freshwater tufa precipitation and its parent water were investigated at Szalajka valley, Sebesvíz and Dobrica Spring (Bükk Mts., Hungary). The aim of the study is to analyse the carbon isotope dynamics of freshwater tufa precipitated in karstic streams between the spring water and the first significant tufa barrage using field measurements, water chemistry, and carbon isotope analysis. A further aim was to examine the fossil tufa precipitations in recently active areas and their neighbourhood to determine their age using the 14C method. Based on the 3H content the water samples are relatively young (<10 y). To calibrate the calendar age of older tufas, dead carbon proportion (dcp) were determined in the recently formed freshwater tufas. The lowest dcp of the recent freshwater tufas was estimated at Sebesvíz (9.6±1.3%), the highest at Szalajka (16.4±2.4%) and a moderate value at Dobrica Spring (13.8±2.2%). Due to the rapid decrease in atmospheric 14C level we have to compensate the atmospheric 14C drop between the water infiltration time and the deposition time of fresh carbonates to compensate the bomb-effect. The oldest fossil tufa age (BC 6421-6096) was found at Sebesvíz located around 20 metres away from the riverbed, while the youngest fossil tufa ages (a few years/decades old) were found in the recently active area at all sites

Induktív csatolású plazma tömegspektrometriai módszerek kidolgozása ólom izotóparányok geológiai mintákban történő meghatározásához = Development of inductively coupled mass spectrometric methods for determination of lead isotope ratios in geological samples

A kutatómunka során ólomizotópok arányainak klinopiroxénekben történő meghatározásához dolgoztunk ki analitikai kémiai módszereket induktív csatolású plazma ionforrással és egy detektorral működő kettős fókuszállású tömegspektrométer felhasználásával. Négy különböző mintabeviteli módszer került összehasonlításra. Az oldatos módszereknél a feltárás után az ólmot koronaéteres gyanta segítségével elválasztottuk a mátrixtól és a zavaró elemektől (Hg, Dy, Er, Yb), majd koncentrikus valamint nagynyomású folyadékporlasztóval történt az aeroszol előállítása és plazmába juttatása. Az izotóparányokra vonatkozó RSD értéke 0.3-0.4% volt. A szilárdmintás mintabevitelt elektrotermikus elpárologtatás (termikus frakcionálás) és lézerabláció útján valósítottuk meg. Az RSD értékek itt 0.6-0.7%, illetve 1.5-1.6% körül változtak. | In framework of our research project analytical methods were developed for determination of isotope ratios of lead in clinopyroxene matrices applying a single collector sector-field mass spectrometer with ion source of inductively coupled plasma. Four different sample introduction techniques were studied. In case of solution techniques the lead was separated from the matrix ant the disturbing elements (Hg, Dy, Er, Yb) applying a corona ether resin. For generation of aerosols Meinhard-type concentric as well as a hydraulic high pressure nebulizer were used. The relative standard deviations of isotope ratios amounted to 0.3-0.4%. For solid sampling electrothermal vaporization (thermal fractionation) and laser ablation were applied. The uncertainty of analytical measurements in these cases was about by factor 2 higher compared to the solution techniques