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EN
The measurements of the advancing contact angle of water, glycerol, formamide, ethylene glycol, diiodomethane, α-bromonaphthalene, 1,2,3-tribromopropane on unoxidized and oxidized galena, pyrite, chalcopyrite, djurleite, bornite and covellite at the temperature equal 293 K were made. Additionally, the measurements of the force air bubble detachment from these sulfide minerals including also chalcocite in water were performed. Using the values of the obtained contact angle of water, glycerol, formamide, ethylene glycol, diiodomethane, α-bromonaphthalene, 1,2,3-tribromopropane the components and parameters of the unoxidized and oxidized sulfide minerals surface tension were calculated. For this calculation the van Oss et al. method was applied after analysis of the components and parameters of the surface tension of liquids used for contact angle measurements. Taking into account the contact angle of water on the sulfide minerals, the detachment force of air bubble from these minerals in water was determined using our equation and comparing to that of measured one. As follows from the measurements and calculations the wetting properties of sulfide minerals and the stability of mineral-air bubble depends to a larger extent on the degree of sulfide minerals oxidation than on the type of mineral.
EN
Surface phenomena play a major role in metallurgical processes; their operation results, among others, from the surface tension of liquid oxidic systems. One of the methods of determining surface tension of oxidic systems is performing calculations with Butler’s method. Surface tension was calculated for two- and three-component liquid oxidic systems typical of metallurgical processes. The determined dependence of surface tension in FeO-SiO2 at temp. 1773 K and CaO-SiO2 at temp.1873 K showed that with the growing participation of SiO2 surface tension decreased. Analogous calculations were performed for three-component systems: CaO-Al2O3-SiO2 and MnO-Al2O3- SiO2. The results of calculations of surface tension were determined for temp. 1873 K and compared with the results obtained by T. Tanaka et al. [19]. In both cases the increase of Al2O3 content resulted in a growth of surface tension. The simulation results were higher than experimental result, as compared to the literature data.
EN
Flotation of soluble salts such as borax, potash, and trona is carried out in their saturated solutions. The high ion concentration of the flotation suspension can affect the floatability of the minerals as well as the coalescence behaviors of the bubbles. The bubble coalescence can be inhibited in the presence of dissolved ions at high ion concentrations as well as with the use of surfactants. In this study, the effect of the mixtures of KCl, NaCl, and dodecyl amine hydrochloride (DAH) on air/water interface was investigated with surface tension and bubble coalescence time measurements for potash flotation. The surface tension measurements indicated that lower surface tension values obtained with mixed KCl and NaCl solutions than their single solutions. In addition, the surface tension of the mixed KCl and NaCl solutions increased with the NaCl and the ionic strength of the solution. The dynamic surface tension measurements indicated that while ion adsorption on air/water interface was so fast, DAH molecules required more time for adsorption probably related to the viscosity of the solution. In addition, the bubble coalescence time measurements showed that the bubble coalescence could be inhibited with the use of DAH in the absence and presence of KCl and NaCl. In the absence of DAH, the bubble coalescence time was determined as 100 ms, 270 ms, and 650 ms, respectively for 100% KCl, 100% NaCl, and 50%KCl+50% NaCl salt solutions. Therefore, the trend in the success of the salt solutions for the inhibition of bubble coalescence can be written as 100%KCl<50%KCl+50%NaCl<100% NaCl according to the bubble coalescence time. The results of this study indicated that there was no clear relationship between the surface tension and the inhibition of the bubble coalescence. However, the bubble coalescence time measurements showed that while the bubble coalescence time was 650 ms in the presence of Na+ ions, it was 100 ms in the presence of K+ ions 100 ms. It can be concluded from the results obtained from this study that the bubble coalescence phenomena may be managed by the specific ion pairing types in solutions which significantly affect the flotation recovery of minerals.
EN
In order to minimize fresh water usage, much attention has been paid to the flotation using saline or sea water. However, the effects of various ions in these waters on froth properties in flotation are not fully understood. In this study, the effects of electrolyte solutions containing NaCl, KCl, CaCl2, and MgCl2 at different concentrations in the presence of terpenic oil as a frother were investigated on froth performance, dynamic froth stability (DFS). It was found that KCl had the best synergistic effects with terpenic oil in reducing the solution surface tension. In the presence of terpenic oil, the DFS and half-life time were reduced with the increased ion concentration. Dynamics foamability index measurements (DFI) confirmed that the increased ion concentration increased the foamability, as frother did. In addition, Gibbs adsorption isotherm suggested that the amount of terpenic oil adsorbed at the gas-liquid interface was increased with the increased ion concentration. This study therefore indicated that the presence of ions can reduce the froth stability but not decline foamability due to terpenic oil, enlighting the application of saline or sea water in defoaming process in flotation.
EN
An emerging ultrasonic technology aims to control high-pressure industrial processes that use liquids at pressures up to 800 MPa. To control these processes it is necessary to know precisely physicochemical properties of the processed liquid (e.g., Camelina sativa oil) in the high-pressure range. In recent years, Camelina sativa oil gained a significant interest in food and biofuel industries. Unfortunately, only a very few data characterizing the high-pressure behavior of Camelina sativa oil is available. The aim of this paper is to investigate high pressure physicochemical properties of liquids on the example of Camelina sativa oil, using efficient ultrasonic techniques, i.e., speed of sound measurements supported by paralel measurements of density. It is worth noting that conventional low-pressure methods of measuring physicochemical properties of liquids fail at high pressures. The time of flight (TOF) between the two selected ultrasonic impulses was evaluated with a cross-correlation method. TOF measurements enabled for determination of the speed of sound with very high precision (of the order of picoseconds). Ultrasonic velocity and density measurements were performed for pressures 0.1-660 MPa, and temperatures 3-30°C. Isotherms of acoustic impedance Za, surface tension σ and thermal conductivity k were subsequently evaluated. These physicochemical parameters of Camelina sativa oil are mainly influenced by changes in the pressure p, i.e., they increase about two times when the pressure increases from atmospheric pressure (0.1 MPa) to 660 MPa at 30°C. The results obtained in this study are novel and can be applied in food, and chemical industries.
6
Content available remote The measurement technique of surface tension using inductance values
EN
The objectives of this study were to examine correlations of inductance values on surface tension of water and to develop other techniques for measuring the surface tension of water using inductance values. The design was based on the variation of inductance values by moving the Ferrite cores that was connected with a conductor plate on water surface when conducting weight counterbalance. The results found that at the surface tension of 66.24 mN/m –71.20mN/m with the inductance values of 0.5mH, 1.0mH and 1.5mH coils.
PL
Celem pracy było zbadanie korelacji wartości indukcyjności naprężeń powierzchniowych wody oraz opracowanie nowych metod pomiaru naporu powierzchniowego wody przy użyciu wartości indukcyjności. Projekt został oparty na zmianie wartości indukcyjności rdzenia ferrytowego, który połączono z płytą przewodową na powierzchni wody przy równoważeniu wagi. Wyniki wykazały, że przy napięciu powierzchniowym 66,24 mN/m -71,20 mN/m indukcyjnoś cewek 0,5 wynosiła0.5 mH, 1.0 mH i 1.5 mH.
EN
The micro air nucleus widely distributed in the ocean is a necessary condition for the cavitation of hydraulic machinery in seawater. In order to study the stability of air nucleus in seawater and cavitation inception, the computational domain of water molecules with air nucleus was studied using the method of molecular dynamics simulation, and the transient characteristics of air nucleus in liquid water were obtained. The key factors influencing nuclei stability were analyzed. The results showed that air nucleus with a certain mass could maintain the dynamic equilibrium in liquid water. The internal density of air nuclei had a critical value that allowed the nuclei to stably exist in water. The air nuclei mass was the decisive factor in its equilibrium volume in water, and the two were positively correlated. The internal density of air nuclei was negatively correlated with the nuclei radius when the nuclei was stable in water. Liquid surface tension was an important factor affecting the stability of the air nuclei. The larger the initial radius of nuclei, the smaller the water pressure, and the more likely the cavitation occurs.
EN
The measurements of advancing contact angle of water, glycerol, formamide, ethylene glycol, diiodomethane, α-bromonaphthalene, 1,2,3-tribromopropane and aqueous solution of n-octyl-β-D-glucopyranoside (OGP) on unoxidized and oxidized synthetic chalcocite at the temperatures equal to 293, 303 and 313 K were made. Using the obtained contact angle values of the pure liquids the components and parameters of the unoxidized and oxidized synthetic chalcocite surface tension were calculated. For this calculation, different methods based on the Young equation were applied. It follows that the surface tension of both forms of chalcocite does not practically depend on the temperature in the range from 293 to 313 K. Taking into account the calculated values of components and parameters of unoxidized and oxidized chalcocite surface tension their wettability by the aqueous solution of n-octyl-β-D-glucopyranoside was considered. It appeared that wettability of the unoxidized chalcocite by aqueous solution of OGP can be predicted on the basis of the chalcocite surface tension components and parameters.
EN
An efficiency of flotation process is strongly dependent upon the collecting ability of air bubbles. On the other hand, the liquid film formed beetween two fully or partially mobile air/liquid interfaces being in contact has low stability, which leads to fast liquid drainage. Therefore, when they approach to each other, they tend to coalescence. Therefore, bubble coalescence is usually controlled with frothers in flotation process. Meanwhile, it is known that dissolved ions inhibit bubble coalescence. In this study, the bubble coalescence in the presence of MIBC was determined using a novel technique with a modified bubble-particle attachment timer. Additionally, the effect of NaCl and CaCl2 on bubble behavior was investigated along with surface tension and bubble coalescence time aspects. As a result of study, it is seen that the bubble coalescence time can be successfully determined with a bubble-bubble coalescence timer.
PL
W pracy przeprowadzono generację nanopęcherzyków azotu w wodzie dejonizowanej za pomocą układów z membranami cylindrycznymi oraz przygotowano roztwory etanolu w wodzie i wodzie z nanodyspersją pęcherzyków. Zbadano wpływ obecności nanodyspersji na lepkość, napięcie powierzchniowe oraz kąty zwilżania szkła. Zbadano wpływ obecności nanodyspersji na lepkość, napięcie powierzchniowe oraz kąty zwilżania szkła. Stwierdzono, że w badanym zakresie stężeń etanolu obecność nanopęcherzyków nie wpływa na lepkość roztworu, podnosi jego napięcie powierzchniowe dla niskich stężeń etanolu (poniżej 20% mas.) oraz zwiększa kąty zwilżania na szkle w badanym zakresie stężeń.
EN
In this work the generation of nanobubbles using the cylindric al-porous-membrane system was performed and mixtures of ethanol in pure water and water with nanobubbles were prepared. The influence of nanodispersion on viscosity, surface tension and contact angles on glass was investigated. The results show that in the investigated range of ethanol concentration a presence of nanobubbles has no influence on liquid viscosity, increases surface tension for low ethanol concentrations (below 20 mass %) and increases the contact angles on glass in the investigated range of concentrations.
EN
The aim of this work is to propose an empirical model for predicting shapes of a Taylor bubble, which is a part of slug flows, under different values of the surface tension in stagnant liquids by employing numerical simulations. The k - turbulence model was used in the framework of finite volume method for simulating flow fields in a unit of slug flow and also the pressure distribution on a Taylor bubble surface. Assuming that an air pressure distribution inside the Taylor bubble must be uniform, a grid search method was exploited to find an appropriate shape of a Taylor bubble for six values of surface tension. It was found that the shape of a Taylor bubble would be blunter if the surface tension was increased. This was because the surface tension affected the Froude number, controlling the flow around a Taylor bubble. The simulation results were also compared with the Taylor bubble shape, created by the Dumitrescu-and-Taylor model and former studies in order to ensure that they were consistent. Finally, the empirical model was presented from the simulation results.
EN
Among the broad variety of anticorrosion coatings, cathodic electrodeposition (CED) primers have an undeniable superiority. Such primers are overcoated with weather resistant coatings to obtain weatherability and the necessary decorative properties. From the point of view of environmental safety and fire protection waterborne stoving paints are of the highest interest, however there is a risk of interlayer adhesion failure due to the primer layer overdrying. In the present work epoxy urethane cathodic electrodeposition primer and polyester melamine paint, containing melamine-formaldehyde cross-linking agents with different alkylation degrees and types as well as an acid catalyst for acceleration of the curing process have been studied. The physical and chemical factors influencing the interlayer adhesion in the system consisting of epoxy urethane CED primer and polyester melamine waterborne stoving paint have been investigated and conditions under which a complete interlayer adhesion failure occurs have been determined.
PL
Spośród szerokiej gamy powłok antykorozyjnych, grunty do katodowego elektroosadzania (CED) mają niezaprzeczalną przewagę. Na powłoki te nakłada się następnie warstwę nawierzchniową, aby uzyskać odporność na warunki atmosferyczne i niezbędne właściwości dekoracyjne. Z punktu widzenia ochrony środowiska i ochrony przeciwpożarowej największe znaczenie wydają się mieć wodorozcieńczalne farby piecowe, jednak istnieje ryzyko utraty przyczepności międzywarstwowej z powodu przesuszenia warstwy gruntu. W niniejszej pracy zbadano grunt epoksydowo-uretanowo i farby poliestrowo-melaminowe, zawierające środki sieciujące melaminowo-formaldehydowe o różnych stopniach i typach alkilowania, a także kwasowy katalizator przyspieszający proces utwardzania. Zbadano fizyczne i chemiczne czynniki wpływające na adhezję międzywarstwową w systemie składającym się z podkładu epoksydowo-uretanowego CED i poliestrowo-melaminowej farby piecowej oraz określono warunki, w których zachodzi całkowita utrata adhezji międzywarstwowej.
EN
Determination of the physico-chemical interactions between liquid and solid substances is a key technological factor in many industrial processes in metallurgy, electronics or the aviation industry, where technological processes are based on soldering/brazing technologies. Understanding of the bonding process, reactions between materials and their dynamics enables to make research on new materials and joining technologies, as well as to optimise and compare the existing ones. The paper focuses on a wetting force measurement method and its practical implementation in a laboratory stand – an integrated platform for automatic wetting force measurement at high temperatures. As an example of using the laboratory stand, an analysis of Ag addition to Cu-based brazes, including measurement of the wetting force and the wetting angle, is presented.
EN
Bismuth oxide thin film was deposited by chemical bath deposition (CBD) technique onto a glass substrate. The grain size (D), dislocation density (δ) and number of crystallites per unit area (N), i.e. structural properties of the thin film were determined as 16 nm, 39.06 x 10-4 line/nm2, 31.25 x 10-3 1/nm2, respectively. Optical transmittance properties of the thin film were investigated by using a UV-Vis spectrophotometer. The optical band gap (Eg) for direct transitions, optical transmission (T %), reflectivity (R %), absorption, refractive index (nr), extinction coefficient (k), dielectric constant (ϵ) of the thin film were found to be 3.77 eV, 25.23 %, 32.25 %, 0.59, 3.62, 0.04 and 2.80, respectively. The thickness of the film was measured by AFM, and was found to be 128 nm. Contact angles of various liquids on the oxide thin film were determined by Zisman method, and surface tension was calculated to be 31.95 mN/m.
EN
In this work, a proposal of non-diffusional description of surface tension reduction in dynamic conditions in systems containing nonionic surfactant Tween80 is presented. The proposed macroscopic model exploits the conception of mass transfer coefficient in liquid phase. In addition, changes in interfacial surface (surface of a growing bubble in the Maximum Bubble Pressure method) are taken into account in the model. Obtained results were compared with the asymptotic solution of Ward and Tordai equation and experimental results.
PL
Przedstawiono propozycję opisu dynamiki obniżania napięcia powierzchniowego układu roztwór niejonowego surfaktantu TweenSOpowietrze. Zaproponowany model wykorzystuje ujęcie makroskopowe procesu z zastosowaniem koncepcji współczynnika wnikania masy w fazie ciekłej. W obliczeniach uwzględniono zmienność pola powierzchni pęcherza na której gromadzi się surfaktant oraz efekty konwekcyjne. Wyniki porównano z asymptotycznym rozwiązaniem Ward-Tordai dyfuzyjnego modelu transportu surfaktantu do powierzchni międzyfazowej oraz wynikami eksperymentalnymi.
PL
Pojazd mechaniczny oraz jego poszczególne elementy konstrukcyjne np. mosty napędowe, ramy, amortyzatory, pracując przy obciążeniu zmiennym, podlegają progresywnemu uszkodzeniu, którego obrazem jest stopniowy rozwój pęknięć zmęczeniowych. Rozwój pękania w konstrukcji oznacza stopniową utratę jej wytrzymałości i zdolności do przenoszenia obciążenia. Celem artykułu jest charakterystyka obciążeń eksploatacyjnych oraz analiza naprężeń oddziałujących na poszczególne elementy konstrukcyjne pojazdu ciężarowego podczas jego użytkowania. Na podstawie analizy literatury oraz własnych obserwacji podjęto próbę rozważań na temat przeładowanych pojazdów ciężarowych i ich wpływu na racjonalną eksploatację taboru w przedsiębiorstwie transportowym.
EN
Motor vehicle and its individual components such as axles, shock absorbers, working with a load variable, are damaged which shows a gradual development of fatigue crack. The development of cracking in structures is the gradual loss of its fatigue strength and ability to carry the load. The aim of the article is to characteristics the load exploitation's load and tensions analysis affecting the individual components vehicle during its utilization. On the basis of an analysis of the literature and own observations, care was consider about overloaded vehicles and their impact on the rational exploitation of the rolling stock in the company.
EN
This paper presents the results of experimental drum granulation of silica flour with the use of wetting liquids with different values of surface tension. Additionally, different liquid jet breakup and different residual moisture of the bed were applied in the tests. The process was conducted periodically in two stages: wetting and proper granulation, during which no liquid was supplied to the bed. The condition of the granulated material after the period of wetting (particle size distribution and moisture of separate fractions) and a change in the particle size distribution during the further conduct of the process (granulation kinetics) were determined.
EN
The paper is a review of the previous investigations concerning the influence of graphite particles both on the casting properties of metal matrix composites (MMCs). The work presents the examination results of casting properties (i.e. castability and shrinkage) of the MMCs with matrices of a selected aluminium alloy reinforced with graphite particles. There is also presented the influence of graphite particles on the surface tension and viscosity of the flowing and filling the mould composite suspension. The suspensions containing various percentages of graphite particles (namely 5%, 10%, or 15% in volume) were prepared in order to perform the above mentioned examinations. Castability (fluidity) of these suspensions was measured in two ways, i.e. by means of both the spiral test and the rod test, while their shrinkage was determined with the use of a device designed and assembled in the Department of Foundry Engineering, CUT. The device enables to determine changes in the length of a casting during its solidification with respect to the specified length of the test rod. The surface tension was determined by the wedge casting method consisting in the pouring of metal into an open shell mould with the cavity of wedge geometry, the sharp edge being perpendicular to the free metal surface. The change in viscosity corresponding to the change in graphite particles percentage was calculated from Einstein’s equation. The results of examinations show that the introduction of reinforcing graphite particles results in both a significant increase in the viscosity of the flowing suspension and a considerable decrease in its castability. The greater dimensional stability of castings was observed, i.e. the shrinkage of composite castings was smaller than the shrinkage of matrix alloy itself. An increase in surface tension index value with an increase in volume percentage of graphite particles in composite was also noticed.
19
Content available remote A novel of surface tension measurement
EN
A new surface tension measurement is presented. The design used variations of relations of distance between parallel conductive plates (d) and the surface tension values ( γ ). This experiment was conducted by measuring the electrical capacitance values which varied due to the surface tension of water at round-shaped parallel conductive plates with 3 in diameters at the surface tension of 64.47mN/m - 72.75mN/m.
PL
Przedstawiono nową metode omiaru napięcia powierzchniowgo bazująca na pomiarze podległości miedzy dwoma przewodzacymi płytkami. Pomiarowi podlega pojemność między tymi płytkami.
EN
The studies evaluated the usefulness of concentrated beetroot juice, chokeberry and beetroot powder as potential tracers of spray deposits as well as their impact on the ability of conidia germination of Isaria fumosorosea and Lecanicillium lecanii. Aqueous solutions of beetroot and chokeberry products affected the physical properties of the spray liquid. The chokeberry juice concentrate at concentration of 2% did not reduced significantly the static surface tension and can be useful as tracer in studies on the quality of spraying. Unfortunately, the chokeberry juice concentrate can be low compatible in mixtures with some adjuvants. Beetroot products lowered significantly static surface tension. Beetroot juice concentrate at a concentration of 2-4% allowed to create stable mixtures with adjuvants and did not influence significantly spreading of droplet. Conidia germination capacity of entomopathogenic fungi was not significantly reduced in solutions of juice concentrates or adjuvants. The mixture of adjuvant and juice concentrate raised the risk of a reduction in ability of conidia germination.
PL
W badaniach oceniono przydatność koncentratu soku z buraka ćwikłowego i aronii oraz proszku buraka ćwikłowego jako potencjalnych wskaźników jakości opryskiwania jak również ich wpływ na zdolność kiełkowania zarodników konidialnych Isaria fumosorosea i Lecanicillium lecanii. Wodne roztwory produktów z buraka ćwikłowego i aronii wpływały na właściwości fizyczne cieczy. Koncentrat soku z aronii w stężeniu 2% nie obniżał znacząco statycznego napięcia powierzchniowego i może pełnić rolę znacznika w badaniach nad jakością opryskiwania. Koncentrat soku z aronii może być jednak niekompatybilny w mieszaninach z niektórymi adiuwantami. Produkty z buraka ćwikłowego obniżały znacząco statyczne napięcie powierzchniowe. Koncentrat soku z buraka ćwikłowego w stężeniu 2-4% umożliwiał uzyskanie stabilnych mieszanin z adiuwantami i nie wpływał znacząco na rozlanie kropli. Zdolność kiełkowania zarodników konidialnych grzybów entomopatogenicznych nie ulegała znaczącemu obniżeniu w roztworach koncentratów soków ani adiuwantów. Połączenie adiuwanta i koncentratu soku podnosiło ryzyko obniżenia zdolności kiełkowania zarodników konidialnych.
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