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1

Compressibility behavior of conditioned sandy clay considering the physical degradation of foam: tunneling issue

Selmi Mœz, Alassaf Yahya, Kacem Mariem, Jamei Mehrez

Journal of Sustainable Mining

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2023

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Vol. 22. iss. 4

316--331

EN

Surfactants in the form of liquid foam are commonly used for ensuring the fluidity of conditioned soil during shield tunneling in mining zone. The compressibility can be significantly affected, depending on the percentage of fine soil. Thus, this paper investigates the compressibility of foam-conditioned fine soil. Oedometric tests as a function of the percentage of foam have been performed. Foam's stability was analyzed, considering a laboratory soil made from 40% kaolinite and 60% of sand and mixed with a foaming agent based on an anionic surfactant. Experimental results showed that the foam stability was manifested through a reduction of the foam's volume followed by liquid drainage, under loading and due to the foam's physical degradation over time. The compressibility increases with the adding rate of the foam in the soil. Therefore, consolidation and foam's degradation over time are two factors that allow the recovery of the compressibility property of conditioned soil.

2

Koloidy w życiu codziennym

Kurek Tomasz, Kuryśko Kacper

Analit

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2023

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Nr 13

6--11

PL

Koloidy, czyli układy złożone z małych cząsteczek rozproszonych w medium, są obecne w wielu aspektach naszego codziennego życia. Jednym z najczęstszych zastosowań koloidów jest żywność. Wiele produktów spożywczych, takich jak mleko, ser i lody, to koloidy. Obecność koloidów w tych produktach może wpływać na ich teksturę, konsystencję i smak. Ponadto są one również stosowane w produkcji wielu produktów kosmetycznych i środków higieny osobistej, w tym balsamów, szamponów i past do zębów. Koloidy mogą pomóc w stabilizacji tych produktów, zapobiegając ich rozdzieleniu i zapewniając jednorodność [1]. Koloidy odgrywają również istotną rolę w miejscach o których większość z nas nie zdaje sobie sprawy, a które mają znaczny wpływ na nasze życie. Na przykład aerozole, w tym dezodoranty czy też leki w postaci sprayu, są koloidami. Układy tego typu nie są jednak tylko sztucznym tworem człowieka. Występują one również naturalnie, w postaci mgły dymu lub chmur. Dzięki koloidom możemy potwierdzić istnienie atomów, a także cieszyć się pięknym błękitnym niebem [2]. Podsumowując, koloidy są wszechobecne w naszym codziennym życiu i mają szeroki zakres zastosowań. Ich obecność znacząco wpływa nie tylko na właściwości i działanie różnych produktów, ale również na cały otaczający nas świat.

EN

Colloids, which are complex systems of small molecules dispersed in a medium, are present in many aspects of our daily lives. One of the most common applications of colloids is in food. Many food products, such as milk, cheese and ice cream, are colloidal suspensions. The presence of colloids in these products can affect their texture, consistency and taste. In addition, they are also used in the production of many cosmetic and personal care products, including lotions, shampoos and toothpastes. Colloids can help stabilize these products, preventing separation and ensuring homogeneity. [1] Colloids also play an important role in areas that most of us are unaware of, but which have a significant impact on our lives. For example, aerosols, including deodorants or drug sprays, are colloids. However, systems of this type are not just an artificial creation of man. They also occur naturally, in the form of smoke mist or clouds. Thanks to colloids, we can confirm the existence of atoms, and enjoy the beautiful blue sky. [2] In summary, colloids are ubiquitous in our daily lives and have a wide range of applications. Their presence significantly affects not only the properties and performance of various products, but also the entire world around us.

3

A Novel Foam Coating Approach to Produce Abrasive Structures on Textiles

Kenttä Eija, Kumar Vinay, Andersson Petter, Forsström Ulla

Autex Research Journal

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2022

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Vol. 22, no. 3

335--342

EN

Abrasive materials are classified as paper, nonwoven, or plastic-based multilayer structures, which are used for different kinds of surface finishing. Currently, the production of abrasive structures on textiles is carried out by spraying a slurry of binder and abrasive particles, e.g., Al2O3 or SiC, with subsequent drying and curing of the binder. The drawback of this production method is the poor runnability of the spraying process. Even small variations in the process parameters may lead to an uneven coating. Therefore, a novel coating approach was developed to produce abrasive structures with foam coating on textile substrates. The foam coating method, which is commonly used in the textile industry, has the potential to produce an even coating layer. The runnability and reliability of the foam coating process are good even with high solids. From a workplace safety perspective, another advantage of foam coating is that there are no airborne particles during the coating process. A polyamide woven cloth was foam coated with an aqueous slurry containing abrasive grains (SiC), a water-based UV-curable acrylate binder, and cellulose nanocrystals (CNCs) to adjust the slurry rheology. Stable abrasive-binder foams were generated from the slurries even at high solids of 50% using an anionic foaming agent. The cloth was foam coated and dried, and the resin was cured with a LED-UV lamp on a pilot scale. It was observed that without the addition of CNC the foam did not stay on the surface of the cloth after coating. CNC acts as a rheology modifier and co-binder, which prevent the foam from penetrating deeper into the pores of the cloth. CNC also acted as a dispersing agent: the slurry was effectively stabilized by the CNC to prevent sedimentation of the abrasive grains. An organic solvent-free composition was introduced by combining CNC with a water-based UV-resin.

4

Study on the foam behavior of amine reagents adsorbed at gas-liquid and gas-liquid-solid interfaces

Shang Kaixuan, Xie Weimin, He Dongsheng, Benzaazoua Mostafa, Chen Fei, Aleksandrova Tatiana N.

Physicochemical Problems of Mineral Processing

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2021

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Vol. 57, iss. 1

192--205

EN

Alkyl amines are widely used as cationic collectors in flotation. In this work, the flotation foaming behaviors of alkyl amines, including dodecylamine (DDA), di-n-hexylamine (DHA), octadecylamine (ODA), oleylamine (OLA), in the presence or absence of quartz were investigated by a new approach, “foam analyzer”. The effects of pH, reagent dosage, concentration of quartz powder, and particle size on foaming property and stability of bubble were explored, and the physical model of foam structure evolution was established. The adsorption mechanism of amines on quartz surface was studied from molecular structure, surface tension, zeta potential, charging mode, and adsorption form. The results show the foam stability of four amine collectors as follows: OLA > ODA > DHA > DDA. In the range of pH=6-10, the foam properties of the four amines are better. Under the same conditions, the longer carbon chain of aliphatic amine, the more unsaturated bonds, the fewer hydrogen atoms of the amine group, and the corresponding foam properties are better. When the concentration of quartz powder is 8-10%, the foaming and stability of the foam of four kinds amines are the best, The finer quartz powder particle size, the more stable the amine foam and the stronger the foamability.

5

Effect of phosphate quality on foam generation during the phosphoric acid production process

Anouar Islaam, Jouraiphy Rim, Essallaki Hicham, Mazouz Hamid, Yousfi Samia, Boulif Rachid, Essaid Bilal, Bouamrani Mouna L.

Physicochemical Problems of Mineral Processing

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2021

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Vol. 57, iss. 2

48--57

EN

The presence of organics materials in phosphate ores generates foam during the manufacture of phosphoric acid, thus affecting the production performance and the quality of the products. Today, in the phosphate industry defoamers are used to reduce the negative impact of foam phosphoric production. In the present work, we focused on root cause evaluation for foam generation during the phosphoric acid production process, we evaluated the effect of phosphate rock quality in terms of organic carbon (OC) and carbonate content, on foam generation using a laboratory protocol for foaming ability evaluation. The results show that there is a relationship between the volume of the foam generated and the values of those impurities, while the volume of foam generated is higher when the concentration of OC and Carbonate is high. In our work, we confirm that the foaming ability of the phosphate rock can be avoided if the concentration of organic carbon less than 0.1% and less than 3% for carbonate.

6

Investigation of gas gathering pipelines operation efficiency and selection of improvement methods

Volovetskyi V. B., Doroshenko Ya. V., Kogut G. M., Dzhus A. P., Rybitskyi I. V., Doroshenko J. I., Shchyrba O. M.

Journal of Achievements in Materials and Manufacturing Engineering

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2021

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Vol. 107, nr 2

59--74

EN

Purpose: The article implies theoretical and experimental studies of the liquid pollution accumulations impact on the efficiency of gathering gas pipelines operation at the Yuliivskyi oil and gas condensate production facility (OGCPF). Research of efficiency of gas pipelines cleaning by various methods. Design/methodology/approach: The research methodology consists of determining the hydraulic efficiency of gathering gas pipelines before and after cleaning of their internal cavity by different methods and comparing the obtained results, which allows to objectively evaluate the efficiency of any cleaning method. CFD simulation of gas-dynamic processes in low sections of gas pipelines with liquid contaminants. Findings: Experimental studies of cleaning efficiency in the inner cavity of the gas gathering pipelines of the Yuliivskyi OGCPF by various methods, including: supply of surfactant solution, creating a high-speed gas flow, use of foam pistons were performed. It was established that cleaning the inner cavity of gas gathering pipelines by supplying a surfactant solution leads to an increase in the coefficient of hydraulic efficiency by 2%-4.5%, creating a high-speed gas flow by 4%-7%, and under certain conditions by 8%-10 % and more. However, for two gas pipelines the use of foam pistons allowed to increase the coefficient of hydraulic efficiency from 5.7 % to 10.5 % with a multiplicity of foam from 50 to 90. be recommended for other deposits.The results of CFD simulation showed that the accumulation of liquid contaminants in the lowered sections of gas pipelines affects gas-dynamic processes and leads to pressure losses above the values provided by the technological regime. With the increase in liquid contaminants volume the pressure losses occur. Moreover, with a small amount of contamination (up to 0.006 m3), liquid contaminants do not have a significant effect on pressure loss. If the contaminants volume in the lowered section of the pipeline is greater than the specified value, the pressure loss increases by parabolic dependence. The increase in mass flow leads to an increase in the value of pressure loss at the site of liquid contamination. Moreover, the greater the mass flow, the greater the impact of its changes on the pressure loss. The CFD simulation performed made it possible not only to determine the patterns of pressure loss in places of liquid contaminants accumulation in the inner cavity of gas pipelines, but also to understand the gas-dynamic processes in such places, which is an unconditional advantage of this method over experimental. Research limitations/implications: The obtained simulation results showed that the increase in the volume of liquid contaminants in the inner cavity of gas gathering pipelines leads to an increase in pressure losses above the value provided by the technological regime. To achieve maximum cleaning of gas gathering pipelines, it is necessary to develop a new method that will combine the considered. Practical implications: The performed experimental results make it possible to take a more thorough approach to cleaning the inner cavity of gas gathering pipelines and to forecast in advance to what extent the hydraulic efficiency of gas gathering pipelines can be increased. Originality/value: The obtained results of CFD simulation of gas-dynamic processes in lowered sections of gas pipelines with liquid contaminants, experimental studies of the effectiveness of various methods of cleaning the inner cavity of gas gathering pipelines has original value.

7

Experimental effectiveness studies of the technology for cleaning the inner cavity of gas gathering pipelines

Volovetskyi V. B., Doroshenko Ya. V., Tarayevs'kyy O. S., Shchyrba O. M., Doroshenko J. I., Stakhmych Yu. S.

Journal of Achievements in Materials and Manufacturing Engineering

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2021

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Vol. 105, nr 2

61--77

EN

Purpose: The purposes of the article are to determine the hydraulic efficiency of two gas gathering pipelines of the Yuliivskyi oil and gas condensate production facility (OGCPF) and develop a set of measures to increase it; to experimentally determine the efficiency of using foams to increase the hydraulic characteristics of the gas gathering pipelines in the Yuliivskyi OGCPF; to develop a set of measures that will help to improve the hydraulic characteristics of gas gathering pipelines. Design/methodology/approach: The research methodology consists in determining the hydraulic efficiency of gas gathering pipelines before and after cleaning their inner cavity with foams with different expansion ratios and comparing the obtained values, which allows to objectively assess the efficiency of this cleaning method. The studies were performed within the framework of research and development work by the specialists of the Ukrainian Scientific Research Institute of Natural Gases. Findings: The pilot testing was carried out to determine the efficiency of cleaning the inner cavity of gas gathering pipelines with foams with different expansion ratios. It showed positive results. It was determined that cleaning the inner cavity of gas gathering pipelines with foams with the expansion ratio from 80 to 90 led to an increase in the hydraulic efficiency coefficient by 10.5%, and with foams with the expansion ratio from 50 to 60 - by 5.7%. The measures taken to clean the inner cavity of gas gathering pipelines from liquid contaminations have proven their efficiency and can be recommended for other fields. Research limitations/implications: The obtained results show that it is reasonable to conduct the experimental studies on the efficiency of cleaning the inner cavity of gas gathering pipelines with the foams with higher expansion ratios. To achieve the maximum quality of cleaning the gas gathering pipelines, it is necessary to develop a new method that will combine the use of foam and gel piston. Practical implications: The performed experimental studies help to take a more reasonable approach to cleaning the inner cavity of gas gathering pipelines with foams and to predict in advance the effect of the foam expansion ratio on the hydraulic efficiency of gas gathering pipelines. Originality/value: The experimental studies on the effect of foam expansion ratios on the hydraulic efficiency of gas gathering pipelines are original.

8

Badania numeryczne przepływu wewnętrznego w różnych typach filtrów

Stanik Magdalena, Caban Szymon, Klonecka Marlena, Buczak Mateusz, Wiśniewski Piotr

Chłodnictwo : organ Naczelnej Organizacji Technicznej

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2021

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R. 56, nr 5

17--22

PL

Jakość otaczającego nas powietrza staje się obiektem powszechnego zainteresowania. W ciągu ostatnich dziesięcioleci oczyszczanie powietrza stało się integralną częścią systemów HVAC, inżynierii procesowej, motoryzacji i ochrony dróg oddechowych. Skuteczna separacja mikroi nanocząstek jest powiązana z opracowywaniem nowych, wyrafinowanych materiałów filtrujących, a także tworzeniem i weryfikacją modeli matematycznych opisujących zachodzące w nich zjawiska. Artykuł dotyczy numerycznego modelowania przepływu powietrza wewnątrz różnych filtrów. Autorzy proponują innowacyjne podejście, w którym bezpośrednio modelowana jest reprezentatywna objętość wewnętrznej struktury materiału filtrującego, a następnie wyniki są uśredniane na podstawie geometrii całego filtra. Prezentowana praca ma na celu walidację czterech modeli materiałów filtrujących, tj. filtra HEPA z włókna szklanego, filtra papierowego stosowanego w motoryzacji, metalowego filtra tkanego oraz pianki poliuretanowej. W artykule zbadano spadek ciśnienia uzyskany dla badanych filtrów. Wyniki analizy numerycznej wskazują dobrą zgodność z danymi eksperymentalnymi, co uzasadnia wykorzystanie proponowanego podejścia w celu dalszych badań.

EN

The quality of the air around us becomes an object of general interest. Over the past decades, air purification has become an integral part of HVAC, process engineering, automotive and respiratory protection systems. Effective separation of micro- and nanoparticles is related with the development of new, sophisticated filtering materials, as well as the generation and verification of mathematical models describing the phenomena occurring in them. The article deals with numerical modeling of air flow inside various filters. The authors propose an innovative approach in which a representative volume of the internal structure of the filter material is directly modeled, and then the results are averaged based on the geometry of the entire filter. The presented work aims to validate four models of filtering materials, i.e. a glass fiber HEPA filter, a paper filter used in the automotive industry, a metal woven filter and polyurethane foam. The article examines the pressure drop obtained for the tested filters. The results of numerical analysis show good agreement with the experimental data, which justifies the use of the proposed approach for further research.

9

Numerical studies of internal flow in different types of filters

Stanik Magdalena, Caban Szymon, Klonecka Marlena, Buczak Mateusz, Wiśniewski Piotr

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2020

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Vol. 24, No 4

335--344

EN

The quality of ambient air attracts considerable, widespread interest. Over the last decades, air purification has become an integral part of HVAC systems, process engineering, automotive and respiratory protection. Efficient separation of micro- and nano- particles is solidly linked with the development of new, sophisticated filtrating materials, as well as generating and validating mathematical models of such porous structures. The paper regards the numerical modeling of various filters. The presented work aims to validate four virtual filtrating materials – the fiberglass HEPA filter, the paper filter used in the automotive industry, knitted wire mesh and polyurethane foam. The pressure drop obtained for the filters under investigation was examined. The CFD results were validated against the data available in the literature. The agreement of the results of numerical and experimental studies proves the suitability of the proposed methods. At the same time, the simplifications employed in the simulations leave room for further improvement in future works.

10

Naprzemienne zatłaczanie wody i gazu (WAG) wspomagane pianą (FAWAG) jako efektywna metoda EOR w złożach szczelinowatych i heterogenicznych

Wojnicki Mirosław

Nafta-Gaz

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2020

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R. 76, nr 5

311--321

PL

Zatłaczanie gazu w procesach wspomagania wydobycia ropy (z ang. enhanced oil recovery – EOR) wiąże się z wystąpieniem niekorzystnego współczynnika mobilności, co często prowadzi do destabilizacji frontu wypierania, tworzenia się języków gazowych i przedwczesnego przebicia zatłaczanego płynu do odwiertów wydobywczych. Jedną z ciekawszych metod, która pozwala na skuteczną kontrolę mobilności gazu, jest naprzemienne zatłaczanie wody i gazu (z ang. water alternating gas – WAG). Łączy ona zalety większej skuteczności wolumetrycznego wypierania ropy (w skali makro) przy zatłaczaniu wody oraz lepszej efektywności wypierania ropy gazem w skali porowej. Największe krajowe nagromadzenia ropy naftowej zlokalizowane są w formacjach węglanowych, które posiadają cechy problematyczne dla procesów EOR, tj. silną heterogeniczność oraz szczelinowatość. Doświadczenia złożowe wskazują, że w takich przypadkach konwencjonalny proces WAG może nie być wystarczający, aby przeciwdziałać niekorzystnym, z punktu widzenia efektywności wypierania ropy, zjawiskom zachodzącym podczas przepływu zatłaczanych płynów. W celu wzmocnienia efektywności procesu WAG stosowane są odpowiednie środki chemiczne, pozwalające na wytworzenie piany, która znacząco ogranicza mobilność gazu i wyrównuje prędkość przepływu między matrycą skalną i systemem szczelin. System pianowy pozwala skierować przepływ zatłaczanych płynów poza strefy o zwiększonej przepuszczalności, zwiększając tym samym skuteczność wypierania ropy w matrycy skalnej. W artykule, który ma charakter przeglądowy, wyczerpująco przedstawiono założenia teoretyczne procesu naprzemiennego zatłaczania wody i gazu wspomaganego pianą (z ang. foam-assisted WAG – FAWAG) oraz jego pozycję na tle pozostałych wariantów metody WAG. Omówiono zastosowanie piany w EOR, scharakteryzowano szczegółowo właściwości piany oraz przedstawiono zagadnienia jej stabilności w ośrodku porowatym. Przybliżono również kwestie mechanizmów odpowiedzialnych za generację piany w ośrodku porowatym. Na koniec krótko scharakteryzowano środki chemiczne stosowane w procesach EOR oraz podano przykłady zastosowań metody FAWAG w skali złożowej.

EN

Gas injection in enhanced oil recovery (EOR) processes is associated with the occurrence of an unfavourable mobility factor. It often leads to the destabilisation of displacement front, viscous fingering and the early breakthrough of the injected fluids into extraction wells. One of the most interesting methods for effective controlling of gas mobility is water alternating gas injection (WAG). It combines the advantages of increased volumetric sweep efficiency (macro-scale) by water injection and improved efficiency of pore-scale oil displacement by gas injection. The largest domestic crude oil accumulations are located in carbonate formations which represent problematic features for EOR processes such as strong heterogeneity and fracturing. Field experience shows that in such cases a conventional WAG process may not be capable to counteract unfavourable (for displacement efficiency) phenomena occurring during the flow of injected fluids. Therefore, suitable chemicals are used to produce foam to enhance the WAG process efficiency. It significantly reduces the mobility of gas and equalises the flow velocity between the rock matrix and fractures. The foam system allows the flow of injected fluids to be directed out of the permeable zones, thus increasing the effectiveness of oil displacement in the rock matrix. In this review paper, detailed principles of the Foam Assisted WAG (FAWAG) process as well as its position among other WAG variants are presented. The application of foam is discussed. The properties of the foam are characterised in detail, and the issues of its stability in the porous medium are presented. The mechanisms responsible for the foam formation in a porous medium are also discussed. Finally, the chemical agents used in EOR processes are briefly characterised, and the examples of FAWAG reservoir scale implementation are presented.

11

Modelling of impulse load influence on the stress state of foam materials with positive and negative poisson’s ratio

Sulym Heorhiy, Mikulich Olena, Shvabyuk Vasyl

Acta Mechanica et Automatica

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2020

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Vol. 14, no. 2

79--83

EN

The influence of impulse load applied for different duration on the distribution of normalised dynamic radial stresses in positive and negative Poisson’s ratio medium was investigated in this study. For solving the non-stationary problem in the case of plane deformation for structurally inhomogeneous materials, the model of Cosserat continuum was applied. This model enables accounting for the influence of shear-rotation deformation of micro-particles of the medium. In the framework of Cosserat elasticity, on applying the Fourier transforms for time variable and developing the boundary integral equation method, solving of the non-stationary problem reduces to the system of singular integral equations, where the components that determine the influence of shear-rotation deformations are selected. The numerical calculations were performed for the foam medium with positive and negative Poisson’s ratio for different values of time duration of impulse. Developed approach can be used to predict the mechanical behaviour of foam auxetic materials obtained at different values of a volumetric compression ratio under the action of time variable load based on analysis of the dis-tribution of radial stresses in foam medium.

12

Formation and elimination of foam in the technological process of potato starch production

Tomtas Paweł, Olejnik Tomasz P.

Przemysł Spożywczy

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2019

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T. 73, nr 1

24--30

EN

The article presents the problem of foaming in liquids in the potato starch production process. The influence of foaming formed in process lines on the maintenance of proper production parameters, as well as on the operation of equipment used in the process is discussed. Foam formed in liquids has a negative impact on the process and requires elimination. The paper discusses methods of foam elimination or ways of limiting the intensity of foam formation. Additionally, benefits of limiting foam formation influencing the stabilization of liquid flow in industrial installations, their influence on the elimination of errors and inaccuracy of liquid flow parameters measurements are presented. Also, the paper analyzes the ways of reducing liquid flow disturbances in systems requiring uniform inflow to devices and apparatuses in the process lines. Simplifying hydraulic systems by eliminating additional elements, such as stabilizing tanks, as well as discarding or limiting the use of chemical anti-foaming agents are also discussed.

PL

W artykule omówiono problem tworzenia piany w cieczach w procesie produkcji skrobi ziemniaczanej. Przedstawiono wpływ tworzącej się piany w węzłach technologicznych na utrzymanie właściwych parametrów produkcji, jak rownież na pracę urządzeń wykorzystywanych w procesie. Tworząca się w cieczach piana ma negatywny wpływ na prowadzony proces i wymaga likwidacji. Omówiono metody likwidacji piany oraz sposoby ograniczenia intensywności jej powstawania. Dodatkowo przedstawiono korzyści wynikające z ograniczenia tworzenia piany wpływające na stabilizację przepływu cieczy w instalacjach przemysłowych, ich wpływ na eliminację błędow i niedokładności pomiarów parametrów przepływu cieczy. Przeanalizowano ograniczenie zaburzeń przepływu cieczy w układach wymagających jednostajnego napływu do urządzeń i aparatów w ciągu procesowym. Przeanalizowano uproszczenie instalacji hydraulicznych związane z rezygnacją z dodatkowych elementów np. zbiorników stabilizujących, jak również rezygnację lub ograniczenie stosowania chemicznych środków antypieniących.

13

Impact of upholstered furniture seat structures on the long-term use comfort

Wiaderek Krzysztof, Wiaderek Iwona, Lange Julia

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology

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2019

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No. 108

39--44

EN

Wpływ konstrukcji mebli tapicerowanych na komfort w okresie długotrwałego użytkowania. Głównym celem pracy była analiza wpływu zmian konstrukcji siedzisk mebli tapicerowanych na pomiar komfortu mebli nowych oraz po długotrwałym ich użytkowaniu. Badania przeprowadzone były przy użyciu maty sensorowej Force Sensitive Applications z odczytem naprężeń kontaktowych oraz profilowanego wgłębia wciskanego w siedzisko siłą 760 N. Okres 5 letniego, długotrwałego użytkowania zasymulowano działaniem cyklicznego obciążenia 1000N x 25000 powtórzeń. Na podstawie przeprowadzonych analiz uzyskanych wyników badań zaobserwowano niekorzystny wzrost współczynnika dyskomfortu D o około 0,8% przy zaobserwowanym spadku o 12,7 % dla siedziska I i 11,5% dla siedziska II. Oznacza to wzrost odczucia komfortu użytkowania siedzisk I i II w okresie użytkowania. Wiąże się to ze spadkiem sztywności siedzisk. Siedziska o niższej sztywności („bardziej miękkie”) wywołują mniejszy nacisk na ludzkie ciało z uwagi na większą powierzchnię użytkową.

14

Structure and properties of polyacrylonitrile/polystyrene and carbon nanoparticle-based nanocomposite foams

Kausar A.

Advances in Materials Science

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2019

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Vol. 19, nr 1(59)

5--20

EN

In this study, novel polyacrylonitrile/polystyrene (PAN/PS) blend has been prepared and reinforced with carbon nanoparticle to form polyacrylonitrile/polystyrene/carbon nanoparticle (PAN/PS/CNP) nanocomposite foam. Acid-functional carbon nanoparticle (0.1-3 wt.%) was used as nano-reinforcement for PAN/PS blend matrix. 2’-azobisisobutyronitrile was employed as foaming agent. The PAN/PS/CNP nanocomposite foams have been tested for structure, morphology, mechanical properties, thermal stability, non-flammability, water uptake, and toxic ion removal. Field-emission scanning electron microscopy and transmission electron microscopy exposed unique nanocellular morphology owing to physical interaction between the matrix and functional CNP. PAN/PS/CNP 0.1 Foam with 0.1 wt.% nanofiller had compression strength, modulus, and foam density of 41.8 MPa, 22.3 GPa, and 0.9 mgcm−3, respectively. Nanofiller loading of 3wt.% (PAN/PS/CNP 3 Foam) considerably enhanced the compression strength, modulus, and foam density as 68.2 MPa, 37.7 GPa, and 1.9 mgcm−3, respectively. CNP reinforcement also enhanced the initial weight loss and maximum decomposition temperature of PAN/PS/CNP 3 Foam to 541 and 574 ºC, relative to neat foam (T0 = 411 ºC; T10 = 459 ºC). Nanocomposite foams have also shown excellent flame retardancy as V-0 rating and high char yield of up to 57% were attained. Due to hydrophilic nature of functional carbon nanoparticle, water absorption capacity of 3 wt.% nanocomposite foam was 30% higher than that of pristine foam. Moreover, novel foams were also tested for the removal of toxic Pb2+ ions. PAN/PS/CNP 3 Foam has shown much higher ion removal capacity (166 mg/g) and efficiency (99 %) than that of PAN/PS foam having removal capacity and efficiency of 90 mg/g and 45 %, respectively.

15

Ocena możliwości wykorzystania analizatora optycznego do badania stabilności piany w piwie ®

Kowalik K., Sykut B., Hus W.

Postępy Techniki Przetwórstwa Spożywczego

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2018

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nr 1

52--56

PL

W artykule przedstawiono metodykę i wyniki badań, których celem była ocena możliwości wykorzystania analizatora optycznego do badania stabilności piany uzyskiwanej z piwa. Urządzenie umożliwia pozyskanie wyników o grubości uzyskiwanej warstwy, procesie jej opadania jak również innych parametrów charakteryzujących pianę. Wadą metody jest pośrednio uzyskiwana wartość grubości warstwy piany i konieczność umieszczania małej próbki w naczyniu pomiarowym.

EN

The article shows the methodology and research results, the aim of which was to assess the possibility of using an optical analyzer to study the stability of foam obtained from beer. The device allows obtaining results about the thickness of the obtained layer, the process of its falling as well as other parameters characterizing the foam. The disadvantage of the method is indirectly obtained value of the thickness of the foam layer and the necessity of placing a small sample in the measuring vessel.

16

Evaluation of flotation reagents by normalization procedures

Drzymala J.

Physicochemical Problems of Mineral Processing

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2018

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Vol. 54, iss. 1

182--192

EN

Froth flotation is a dynamic multiphase process in which particulate matter is separated with the help of chemical reagents by gas bubbles immersed in water. The original flotation results are usually presented in the form of kinetic curves relating recovered particulate matter mass (yield ) or mass of a selected component (recovery ), both shortly denoted as y, versus process time t at different concentrations c (g/dm3) of the applied reagents. The kinetic curves can be modified into three: incentive (maximum yield or recovery ymax vs c), limits (ymax vs kinetic constant k or specific rate) and half-life of flotation (t1/2 vs c) curves. The original and modified curves can be normalized by taking into account either an external parameter such as molecular mass (MW), critical coalesce concentration (CCC), critical concentration at the minimum bubble velocity (CMV), dynamic foaming index (DFI), and many other parameters or an internal parameter such as time, concentration needed to achieve certain yield, recovery (y) or kinetic constant. Normalization leads to new flotation curves and provides additional useful information about flotation performance. Normalization can be fully effective, partial or ineffective. Normalization of the original flotation kinetic curves usually is ineffective. Also, normalization of the incentive curve with external parameters such as frother molecular mass, which changes reagent concentration from c (g/dm3) to C (mol/dm3), is also ineffective. Partially effective are normalizations with other external parameters such as CCC and CMV, usually within the same class of regents, for instance alcohols. Only DFI seems to be a universal external normalization parameter for flotation results because it provides fully effective normalization and thus predicts the flotation results. Limited data on DFI restrict a full verification of this hypothesis. Normalization of the modified flotation curves with internal parameters such as k50 (value of 1st order kinetic constant when recovery or yield is 50% after a given flotation time), Ct1/2 (frother concentration in mol/dm3 at which the flotation half-life has an arbitrarily chosen value) and cy75 (frother concentration in g/dm3 at which recovery or yield is 75% after a given flotation time) is a good base for practical classification of flotation reagents.

17

Modelowanie procesu napełniania przy użyciu obliczeniowej mechaniki płynów

Makowski Ł., Wyszomierska E., Grochowiecki M.

Inżynieria i Aparatura Chemiczna

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2018

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Nr 4

102--103

PL

Celem pracy było przeprowadzenie symulacji procesu napełniania pojemników cieczami pieniącymi się o różnych właściwościach reologicznych oraz określenie wpływu tych właściwości na ułamek objętościowy powietrza w cieczy. Wykazano, że zgodnie z przewidywaniami największy wpływ ma lepkość oraz napięcie powierzchniowe płynu. Im niższa wartość napięcia powierzchniowego tym powstawała większa liczba pęcherzyków powietrza podczas procesu napełniania. Dla cieczy o dużej lepkości proces przebiegał odmiennie - zatrzymane powietrze w cieczy w trakcie procesu dużo wolniej zanika niż przy nalewaniu cieczy o małej lepkości.

EN

The aim of this work is to simulate the process of filling containers with foaming liquids with different rheological properties and to determ ine the effect of these properties on the volume fraction of air in the liquid. It has been shown that, as predicted, viscosity and surface tension of the fluid have the greatest influence. The lower the surface tension, the greater the number of air bubbles during the filling process. For viscous liquids the process is different - the air retained in the liquid during the process disappears much slower than when pouring Iow viscosity liquids.

18

Możliwości uaktywnienia mechanicznego oddziaływania w procesie mycia metodą CIP

Diakun J.

Inżynieria i Aparatura Chemiczna

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2017

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Nr 6

193--195

PL

Praca ma charakter analityczno-koncepcyjny. Na podstawie przeglądu literatury, badań własnych oraz obserwacji procesów przemysłowych przeanalizowano warunki mycia instalacji przemysłowych metodą CIP. Celem pracy była identyfikacja ograniczeń tej metody mycia, skutków energetycznych i środowiskowych oraz możliwości uaktywnienia mycia metodą CIP poprzez zastosowanie metod hybrydowych takich jak: oddziaływanie kawitacji ultradźwiękowej, barbotażu, piany oraz wkładek-korków przepływowych.

EN

This work presents an analytically-conceptual character. On the basis of literature survey, our own research and industrial process observation, CIP cleaning conditions of industrial lines were analyzed. The aim of this study was to identify limitations of this washing method, energy and environmental effects and the possibility of activating CIP washing using hybrid methods such as ultrasonic cavitation, bubbling, foam and inserts-flow caps.

19

Glassy carbon foams as skeleton reinforcement in polymer composite

Myalski J., Hekner B.

Composites Theory and Practice

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2017

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R. 17, nr 1

41--46

EN

Glassy carbon foams were produced by the pyrolysis process using polyurethane foam with a layer of phenol-formaldehyde resin as the precursor. The pyrolysis process was conducted in vacuum conditions at 1000°C. The pyrolysis conditions were determined on the basis of carried out thermogravimetric analysis. The basic mechanical properties like the compressive strength of the carbon foams was measured and compared with the theoretical value. Furthermore, the glassy carbon foams were applied as skeleton reinforcement in epoxy resin matrix composites. Analysis of the mechanical properties revealed that the values of hardness and compressive strength of materials with spatial carbon foam are almost two times higher than for a pure matrix applied as the reference material. The major factors that influenced the final mechanical properties are the quality of the obtained foams and the amount of carbon in the material volume. Moreover, it was proved that the application of carbon foam with low mechanical properties led to significant increases in the compressive strength of the composite materials.

PL

Prezentowane w niniejszej pracy pianki z węgla szklistego zostały otrzymane w procesach pirolizy preform poliuretanowych z warstwą żywicy fenolowo-formaldehydowej. Proces pirolizy został przeprowadzony w warunkach odmiennych w stosunku do stosowanych powszechnie technologiach. W tym przypadku zastosowano próżnię oraz temperaturę 1000°C. Warunki pirolizy określono na podstawie przeprowadzonej analizy termograwimetrycznej. Właściwości mechaniczne otrzymanych pianek węglowych wyznaczono na podstawie wytrzymałości na ściskanie. Otrzymane dane porównano z wartościami teoretycznymi wyznaczonymi według równania Ashby’ego i Gibsona. Ponadto, w ramach badań wytworzono kompozyty z osnową polimerową, wzmocnione prezentowanymi pianami węglowymi. Analiza właściwości mechanicznych wykazała, że wartość twardości oraz wytrzymałości na ściskanie kompozytów wzmocnionych strukturami węglowymi jest niemal dwukrotnie wyższa od wartości czystej żywicy epoksydowej - materiału referencyjnego. Określono, że najważniejszymi czynnikami mającymi wpływ na właściwości mechaniczne są jakość wytworzonej pianki oraz ilość węgla w objętości materiału kompozytowego. Ponadto zostało udowodnione, że zastosowanie pianek węglowych o niskich właściwościach mechanicznych prowadzi do znacznego wzrostu wytrzymałości na ściskanie materiałów kompozytowych na osnowie polimerowej.

20

Strengthening and toughening mechanisms for polypropylene/Glass fiber composite foams under three-phase coexistence

Gong W., Yu J., Fu H., Zhang C., He L.

Polimery

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2015

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T. 60, nr 7-8

457--461

EN

Composite foams were obtained through a two-step molding process in an injection molding machine. Gas phase was introduced into the mixture of molten polypropylene (PP) and solid glass fiber (GF). The interfacial behavior was investigated, and the strengthening and toughening mechanisms for PP/GF composites under three-phase coexistence were discussed. The incorporation of gas phase significantly increased the tensile strength by 112 % and impact toughness by 105 % in comparison to its unfoamed counterpart. The resulting mechanical properties of the PP/GF composite foams were found to depend considerably on the coexistence state of solid (GF) and gas (cells) phases and the cell structure of the foams.

PL

Pianki kompozytowe otrzymano w dwustopniowym procesie formowania wtryskowego. Fazę gazową wprowadzano do mieszaniny stopionego polipropylenu (PP) ze stałymi włóknami szklanymi (GF). Badano właściwości mechaniczne otrzymanych pianek PP/GF oraz omówiono mechanizmy powodujące wzmacnianie i utwardzanie tych pianek w warunkach współistnienia trzech faz. Zaobserwowano, że wprowadzenie fazy gazowej znacznie zwiększa wytrzymałość na rozciąganie (o 112 %) i udarność pianki (o 105 %) w porównaniu z wartościami otrzymanymi w przypadku jej niespienionego odpowiednika. Stwierdzono, że właściwości mechaniczne pianek kompozytowych PP/GF w znacznym stopniu zależą od stanu współistnienia fazy stałej (GF) i gazowej (pory) oraz struktury komórkowej pianki.