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1

Proposition of a bubble-particle attachment model based on DLVO van der Waals and electric double layer interactions for froth flotation modelling

Buchmann Markus, Öktem Gülce, Rudolph Martin, Boogaart K. Gerald van den

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 5

art. no. 154812

EN

The attachment of bubbles and particles represents one of the sub-processes in froth flotation among others (e.g. collision and detachment). The main interactions present at short distances in such a bubble-particle system are the van der Waals and electrostatic double layer interactions combined in the DLVO theory. In this study, the special features of the attachment process were discussed with a focus on flotation. For the van der Waals interactions, the Hamaker constants were calculated with the help of Lifshitz´ macroscopic theory as a function of the separation distance for specific material combinations. A specific material system (PbS-Water-Air) was used to demonstrate the implementation of bubble-particle attachment of the proposed modelling framework. The effects of additional surfactant/collector and air layers on the solid interface were presented. This framework of layered systems showed that the sign of van der Waals interaction could be turned from repulsive to attractive without the need to extend the DLVO theory. The thickness of the layer as a function of collector adsorption between a particle and a bubble is suggested as a modelling parameter in bubble-particle attachment efficiency.

2

Podział i charakterystyka koparek jednonaczyniowych

Bodziony Przemysław, Kasztelewicz Zbigniew, Patyk Michał

Kruszywa : produkcja - transport - zastosowanie

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2019

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Nr 2

44--49

PL

Koparki jednonaczyniowe stanowią jeden z najważniejszych typoszeregów maszyn stosowanych w budownictwie, inżynierii środowiska oraz górnictwie. Stąd zróżnicowane kryteria ich klasyfikacji. Ogólnie o podziale decydują: przeznaczenie, cechy konstrukcyjne mające wpływ na rodzaj użytkowania, a także rodzaj osprzętu, masa eksploatacyjna, technologia wykonywania procesów roboczych. Koparki jednonaczyniowe często stanowią składową układów technologicznych kopalni odkrywkowej oraz systemów maszynowych stosowanych w budownictwie i inżynierii środowiska jako grupa maszyn roboczych ciężkich, przeznaczonych do urabiania i ładowania odspojonego urobku na dowolne środki transportowe.

EN

Single-bucket excavators are one of the most important series of types of machines applied in building industry, environmental engineering and mining industry. Therefore, their classification criteria are so diverse. In general the division can be made by: intended use, design features affecting the type of occupation as well as type of attachment, operating weight, operating processes technology. Single-bucket excavators are often a part of process systems in surface mining and machinery systems applied in building industry and environmental engineering as a group of heavy engineering machines, designed for mining and loading of separated output on any transport equipment.

3

Znaczenie więzi w kontekście rozwoju biopsychospołecznego człowieka

Piekacz A., Trepka-Starosta J.

Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska

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2018

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z. 123

387--396

PL

W wielu opracowaniach naukowych jako znaczący czynnik ochronny przed występowaniem problemów społecznych, wskazuje się prawidłowe więzi społeczne. Dojrzałe zachowania społeczne będące fundamentem związku jednostki z grupą/ zbiorowością są mocno zakorzenione w historii rozwoju relacji przywiązania. W sytuacji gdy zaburzona jest relacja przywiązaniowa we wczesnym dzieciństwie dochodzi do trwałych zmian w rozwoju psychicznym jednostki. U osób z traumą relacyjną występują poważne trudności z regulacją i modulacją pierwotnych emocji, takich jak strach i wściekłość. Część tych symptomów stanowią również tendencje do zachowań impulsywnych (Liotti, Farina, 2016). Tak rozumiana trauma zaburza lub całkowicie uniemożliwia zdolność budowania relacji społecznych. Współczesna wiedza o człowieku skłania do holistycznego rozumienia wzajemnych powiązań między ciałem a umysłem. Dzięki neuronaukom wiadomo, że pewne struktury mózgu, czy szlaki nerwowe nie są w stanie się prawidłowo rozwinąć czy dojrzeć bez bliskiego kontaktu z drugim człowiekiem. Struktury mózgu regulujące reakcje przywiązaniowe nie dojrzewają samoistnie – do ich rozwoju potrzebny jest kontakt z drugim człowiekiem. Człowiek jest jednością biopsychospołeczną, a więc wszelkie doświadczenia społeczne mają wpływ na stan biochemiczny organizmu i przekładają się na jego reakcje behawioralne. Celem artykułu jest przedstawienie aktualnych doniesień naukowych z obszaru badań nad więziami w pojęciu biopsychospołecznym. Poprzez zestawienie różnych koncepcji wskazanie na potrzebę uwzględniania rozwoju relacji przywiązania w profilaktyce problemów społecznych.

EN

In many scientific studies, social bonds are indicated as a significant protective factor against the occurrence of social problems . Mature social behaviors that are the foundation of the individual's relationship with the group / collectivity are deeply rooted in the history of the development of attachment relations in the early stages of human life. In a situation where an attachment relationship is disturbed in early childhood permanent changes in the psychological development occur. People with relational trauma have serious difficulties regulating and modulating their original emotions, such as fear and rage. Some of these symptoms also constitute tendencies to impulsive behaviors (Liotti, Farina, 2016). Trauma understood in this way disturbs or completely prevents the ability to build social relations. Contemporary knowledge about a human being leads to a holistic understanding of the mutual connections between the body and the mind. Thanks to neurosciences, it is known that certain brain structures or nerve pathways are unable to properly develop or mature without close contact with another human being. Brain structures that regulate attachment reactions do not self-ripen – they need contact with another human being to develop them. Man is a biopsychosocial unity, and therefore all social experiences have an impact on the biochemical state of the body and translate into its behavioral responses. The aim of the article is to present current scientific reports from the area of research on ties in the biopsychosocial concept. By comparing different concepts, the need to consider the development of attachment relations in the prevention of social problems.

4

Surface roughness in bubble attachment and flotation of highly hydrophobic solids in presence of frother – experiment and simulations

Kosior D., Kowalczuk P. B., Zawala J.

Physicochemical Problems of Mineral Processing

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2018

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Vol. 54, iss. 1

63--72

EN

In this paper, the kinetic of the three-phase contact (TPC) formation and the flotation recovery of highly hydrophobic solids with different surface roughness were studied in pure water and aqueous solutions of n-octanol. The surface roughness varied between 1 to 100 μm. It was found that there was a strong influence of surface roughness on both kinetics of TPC formation and flotation. The time of three phase contact formation and flotation rate were much faster for rough surfaces in both water and aqueous solutions of frother. Irrespective of the surface roughness, at above a certain frother dose, the attachment time increased and the flotation rate decreased. It was related to the presence of air at the hydrophobic solid surfaces. The mechanism of this prolongation of the time of TPC formation at the solid surfaces with different roughness due to the frother overdosage was discussed, and the experimental data were confirmed by numerical simulations.

5

A new etching trace from the Savignone Conglomerate (Oligocene), NW Italy, probably produced by limpet gastropods

Uchman A., Rattazzi B.

Acta Geologica Polonica

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2018

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Vol. 68, no. 4

651--662

EN

A new ichnogenus and ichnospecies (Solealites ovalis) of etching trace is preserved on the surfaces of clasts from the Savignone Conglomerate (Oligocene) in the Palaeogene Piemonte Basin in NW Italy. It is a shallow, oval depression with a central elevation, which was produced probably by limpet gastropods and served as their home scar, but other gastropods or even sea anemones are not excluded as the trace makers. The conglomerate is interpreted as a deposit of a fan delta, whose clasts have been bioeroded in an intertidal and shallow subtidal shore zone and redeposited to the deeper sea.

6

A study of bubble-particle interactions in a column flotation process

Cheng G., Shi C., Yan X., Zhang Z., Xu H., Lu Y.

Physicochemical Problems of Mineral Processing

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2017

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Vol. 53, iss. 1

17--33

EN

Bubble-particle interactions play an important role in flotation. This study examines the behaviour of bubble clusters in a turbulent flotation cell. Particularly, the bubble-particle interaction characteristics in flotation are investigated. The bubble size in a flotation column was measured using an Olympus i-SPEED 3 high-speed camera. Relationships between the circulating volume, bubble size and bubble terminal velocity were discussed. Probabilities of collision, attachment, detachment and acquisition between bubbles and particles in different circulating volumes were calculated based on the flotation kinetic theory. Using the extended Derjaguin–Landau–Verwey–Overbeek (EDLVO) theory, the relationship between the potential energy and distance in bubble-particle interaction was analysed. The results demonstrated that as the circulating volume increased, the bubble size and velocity decreased. When the circulating volume increased from 0.253 to 0.495 m3/h, the bubble diameter decreased from 511 to 462 μm, and the corresponding bubble velocity decreased from 43.1 to 37.5 mm/s. When the circulating volume remained constant as the particle size increased, probabilities of collision, attachment, detachment and acquisition increased. When the particle size remained constant as the circulating volume increased, these probabilities also increased. At a constant circulating volume as the particle size increased, the absolute value of the total potential energy between the particle and bubble increased. When the distance between the bubble and particle was 30 nm, the energy barrier appeared.

7

Some remarks on attachment of a gas bubble to another phase both immersed in water

Kowalczuk P. B., Drzymala J.

Physicochemical Problems of Mineral Processing

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2016

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Vol. 52, iss. 1

147--154

EN

In this paper the importance of definition of hydrophobicity and aquaoleophilicity in terms of contact angle as well as the properties of water films in flotation and oil agglomeration were briefly presented. It was shown that the hysteresis of contact angle for a considered system depends on the way of measurement and geometry of the system due to the presence of other that excess pressure and capillary forces and buffering properties of the capillary force. It was suggested that, the measured advancing and receding contact angles should be, when possible, recalculated into the Young (rest, equilibrium) contact angle. It was discussed that quartz is not a good model of hydrophilic surface because its contact angle with a gas phase in water is not zero and that a spontaneous attachment between highly hydrophobic materials such as hydrocarbons and Teflon in dynamic system, such as flotation, does not occur.

8

The evaluation of selected attachment systems for implant-retained overdenture based on retention characteristics analysis

Chladek G., Wrzuś-Wieliński M.

Acta of Bioengineering and Biomechanics

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2010

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Vol. 12, no. 3

75-83

EN

The results of mechanical characteristics of attachments used for retaining and stabilizing overdenture have been analysed. Two commercially used attachments (a ball attachment and a bar attachment) and elastic frictional attachments designed by the research team with Professor Chladek as the leader have been investigated. The diagrams of force–displacement characteristics have been registered. Retention forces (FR) have been determined and total work (WT) disconnecting the attachments has been calculated on the basis of these diagrams. The analysis of total work corresponding to different types of attachments made it possible to distinguish some characteristic areas which illustrate specific features of particular designs. It has been revealed that determining the retention force allows us to compare only the attachments which work on similar bases. In order to conduct a purely objective comparison of the efficiency of different designs, it is necessary to analyze complete force–displacement characteristics as well as to determine on this basis the subsequent phases of separating the parts of attachments and to find the value of the work which in fact determines their quality. The comparison of selected commercially used designs and the presented elastic frictional attachments (taking into account the criterion of work) gives clear evidence that the introduced design of attachment enables us to create very good conditions of retaining overdenture.

9

Attachments of implant retained tissue supported denture under biting forces

Żmudzki J., Chladek W., Krukowska J.

Archives of Computational Materials Science and Surface Engineering

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2009

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Vol. 1, nr 1

13-20

EN

Purpose: In implant retained soft tissue supported type dentures functioning of attachments, presented by their producers as mechanically bio-compatible because of the ensured freedom of rotational displacements is accompanied by numerous problems that seem to be caused by excessive bearing of occlusal loads. Design/methodology/approach: For the purposes of attachments loadings evaluation, built was a threedimensional FEM model of a denture situated on an atrophic prosthetic foundation with joint supports assumed in the area of denture attachment to implants. Analysis of attachments loadings has been carried out under unilateral oblique occlusal forces of 100N in molars and incisors zones. Findings: Used methodology made it possible to determine attachments loading in a quantitative manner. In spite of free rotational movements implantological supports bear significant part of horizontal occlusal forces components, which reach the value of 66N during chewing processes. Research limitations/implications: Examined was only the most commonly used type of attachments. Hence, further studies, apart from constrains enabling rotational movements introduced should be also an axial compliance which is already offered by some types of attachments, and which additionally enables sedimentation of the denture towards the axes of implants. Practical implications: Analysis of loadings related to implantological attachments in case of assuming only a vertical component of occlusal forces leads to a significant underestimation of implantological supports loads values. In the presented analysis, taking into account the influence of the obliquely acting occlusal forces that occur in real chewing conditions, it has been proved that freedom of rotational movements of overdenture's attachments does not allow to use the natural supports of mucous membrane. That explains the reason of attachments and acrylic resin dentures damages, as well as the significant number of lost implants of upper denture resulting from biomechanical causes. In clinical practice, achieved should be the most anterior implants' placement, and especially in case of flat ridges because of the lack of any bearing surface. Originality/value: Determined loadings of supports might constitute a starting point for further biomechanical evaluation of attachments solutions that function according to similar principles, without the necessity of building complex models of the whole system.

10

Elastic silicone matrices as a tool for load relief in overdenture implants

Żmudzki J., Chladek W.

Acta of Bioengineering and Biomechanics

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2008

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Vol. 10, nr 4

7-14

EN

The objective of this study was to analyze how the elasticity of matrices attaching to an overdenture affects implants and how the location of implants affects their loading. The attachments proposed made from elastic matrix increase the denture stability and simultaneously preserve the mechanisms of occlusion load transfer in compliance with principles usually applied in the denture used in the case of edentulous maxilla or mandible. It was revealed that denture dislodgement caused by occlusion forces did not result in the force being greater than the attachment retention force determined empirically. Our analysis also demonstrates that in the case where the implants are inserted in such a way that they are shifted too much to the back area of the tooth arc, an increase in the implant bending occurs, with the supporting capacities of alveolar processes not being fully utilized. This fact suggests the necessity to increase the susceptibility of attachments in a posterior location.

11

Resonance contributions to low-energy electron collisions with molecular hydrogen

Horáček J., Čížek M., Houfek K., Kolorenč P., Pichl L.

Nukleonika

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2003

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Vol. 48, nr 2

109-112

EN

Calculations of electron dissociative attachment and vibrational excitation of molecular hydrogen by low-energy electrons based on an improved nonlocal resonance model are reported. The role of the rotational excitation of the target molecules is discussed.

12

The effect of liquids on the interaction between coal particles

Ogonowski R., Wójcik W., Jańczuk B.

Physicochemical Problems of Mineral Processing

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2001

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Vol. 35

43-53

EN

Taking into account the published earlier values of the destruction time of the coal column structure formed from the four fractions of coal particles having the average diameter 1.5x10-4 m, 2.5x10-4 m, 3.5x10-4 m and 4.5x10-4 m in the homologous series of alkanes and alcohols, the correlation between destruction time and bulk properties of coal and liquids as well as the liquid-air, coal-air and coal-liquid interfacial properties was studied. On the basis of this study the linear relationship between the reciprocal destruction time and average diameter of the coal fractions, work of alkane and alcohol cohesion, their density, the difference between liquids and coal density, and free energy of interactions per one molecule of the liquid was found. From these relationships, the critical values of the particles diameter, work of cohesion, density, difference between coal and liquid density, and free energy of interactions for infinitely long destruction time were determined. It was stated that for systems having critical values of these parameters, the detachment force is equal to the attachment one. From study it also results that the attachment forces between coal particles depend on the work of cohesion of liquid and work of adhesion of coal to liquid, and that the destruction of the structure of the sediment column take place as a result of the interruption of the film of the liquid between two coal particles.

PL

Wykorzystując opublikowane wartości czasu destrukcji struktury słupka sedymentu w rurce szklanej dla frakcji ziaren węgla o średniej średnicy 1.5x10-4m, 2.5x10-4m, 3.5x10-4m i 4.5x10-4m, w węglowodorach od heksanu do heksadekanu i alkoholach od metanolu do dekanolu, przeprowadzono badania nad korelacją pomiędzy czasem destrukcji a właściwościami objętościowymi badanych cieczy i węgla oraz międzyfazowymi ciecz-powietrze, węgiel-powietrze i węgiel-ciecz. Na podstawie przeprowadzonych badań stwierdzono, że czas destrukcji rośnie ze wzrostem długości łańcucha węglowodorowego alkanów i alkoholi a maleje ze wzrostem średniej średnicy ziaren węgla. Zmiany czasu destrukcji wynikają z różnicy pomiędzy siłami odrywającymi ziarno węgla od ziarna węgla a siłami adhezyjnymi (zlepienia), które odpowiednio zależą od oddziaływań grawitacyjnych i międzyfazowych. Obliczone siły odrywające, przy założeniu, że ziarna węgla są kulkami, maleją ze wzrostem długości łańcucha węglowodorowego badanych cieczy. Dla obu badanych szeregów homologicznych stwierdzono liniową zależność pomiędzy odwrotnością czasu destrukcji słupka sedymentu i średnią średnicą badanych frakcji ziaren węgla, pracą kohezji alkanów i alkoholi, ich gęstością, różnicą gęstości węgla i badanych cieczy oraz swobodną energią oddziaływań w przeliczeniu na jedną cząsteczkę cieczy. Prostoliniowe zależności pozwoliły na wyznaczenie tzw. „krytycznych wartości” takich parametrów jak: średnica ziaren, praca kohezji, gęstość, różnica gęstości i swobodna energia oddziaływań dla nieskończenie długiego czasu destrukcji (1/t=0). Dla układów o krytycznych wartościach wymienionych parametrów siły odrywania równe są siłom zlepienia. Biorąc to pod uwagę obliczono promień płaszczyzny kontaktu oraz wielkość sił zlepienia pomiędzy ziarnami węgla w badanych cieczach. Przeprowadzone obliczenia wykazały, że siły zlepienia pomiędzy ziarnami węgla są nieco wyższe od pracy kohezji badanej cieczy. Wynika z tego, że o wielkości sił zlepienia pomiędzy ziarnami węgla w badanych cieczach decyduje nie tylko wielkość pracy kohezji danej cieczy ale również wielkość pracy adhezji węgiel-badana ciecz. Ponieważ praca adhezji jest większa od pracy kohezji, zatem niszczenie struktury słupka sedymentu ziaren węgla zachodzi w wyniku przerwania ciekłego filmu pomiędzy dwoma ziarnami węgla.