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1

Effects of different grain size of expanded perlite aggregate and content of silica aerogel on the characteristics of lightweight cementitious composite

Vashchuk Andrii, Ślosarczyk Agnieszka

Physicochemical Problems of Mineral Processing

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2023

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Vol. 59, iss. 4

art. no. 174338

EN

In this research, an attempt was made to investigate effects of expanded perlite aggregate grain size on consistency, density, compressive strength, thermal conductivity and microstructure of 15 different composite mixes with silica aerogel. As for the samples preparation, expanded perlite aggregate of 5 different groups based on grain size, were used for sample preparation, then partially replaced by volume for 20% and 40% of hydrophobic silica aerogel particles. The results showed, that density of the samples varied between 0.35 g/cm3 and 1.5 g/cm3, flexural strength varied between 3.4 MPa and 7.4 MPa, compressive strength was in the range between 12.3 MPa and 55 MPa, thermal conductivity coefficient was in the range between 0.130 W/mK and 0.190 W/mK. Scanning electron microscopy showed that expanded perlite aggregates and silica aerogel particles are capable of being mixed and formed homogenous mixture. Nevertheless, microscope images indicated weaker adhesion of silica aerogel particles at interfacial zone as compared with expanded perlite aggregate particles. Results revealed, that both of the factors: grain size of expanded perlite aggregate particles silica aerogel content influenced the density, compressive strength and thermal conductivity. The study also indicated feasibility of expanded perlite aggregate and silica aerogel for achieving homogeneous mixture of the lightweight cementitious composites. Study demonstrated that using different size fractions of expanded perlite aggregate affects differently physical, mechanical and thermal characteristics of the lightweight cementitious composite with silica aerogel.

2

Environmentally hazard and toxic exoskeletons of marine crustaceans wastes in synthesizing N-deacetylated chitin

El-Mekawy Rasha E.

Polimery

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2022

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Vol. 67, nr 10

503--508

EN

High molecular weight chitosan was synthesized from shrimp shells. Chemical structure of chitosan was confirmed using FT-IR, XRD, TGA, and SEM analyses. Physicochemical properties of chitosan such as molecular weight (800 000 g/mol), deacetylation degree (80%), ash content (1%) indicating effectiveness of demineralization step in removing minerals, water binding capacity (4220%), and fat binding capacity (537%), were determined. FT-IR spectra exhibited characteristic joint band at 3365 cm-1 due to –OH and –NH2 regarding to the conversion of chitin acetyl group to NH2 of chitosan.

PL

Z muszli krewetek zsyntetyzowano chitozan o wysokiej masie cząsteczkowej. Strukturę chemiczną chitozanu potwierdzono metodami FT-IR, XRD, TGA i SEM. Określono właściwości fizykochemiczne chitozanu takie jak masa cząsteczkowa (800 000 g/mol), stopień deacetylacji (80%), wskazu jącą na skuteczność procesu demineralizacji zawartość popiołów (1%), zdolność wiązania wody (4220%) i zdolność wiązania tłuszczu (537%). Widma FT-IR wykazały charakterystyczne pasmo przy liczbie falowej 3365 cm-1, pochodzące od grup –OH i–NH2, wynikające z przekształcenia grupy acetylowej chityny w NH2 chitozanu.

3

Hardfacing of mild steel with wear-resistant Ni-based powders containing tungsten carbide particles using powder plasma transferred arc welding technology

Appiah Augustine Nana Sekyi, Bialas Oktawian, Żuk Marcin, Czupryński Artur, Konadu Sasu David, Adamiak Marcin

Materials Science Poland

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2022

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Vol. 40, No. 3

42--63

EN

This study explores the use of powder plasma transferred arc welding (PPTAW) as a surface layer deposition technology to form hardfaced coatings to improve upon the wear resistance of mild steel. Hardfaced layers were prepared using the PPTAW process with two different wear-resistant powders: PG 6503 (NiSiB + 60% WC) and PE 8214 (NiCrSiB + 45% WC). By varying the PPTAW process parameters of plasma gas flow rate (PGFR) and plasma arc current, hardfaced layers were prepared. Microscopic examinations, penetration tests, hardness tests, and abrasive wear resistance tests were carried out on the prepared samples. Hardfacings prepared with PG 6503 had a hardness of 46.3–48.3 HRC, while those prepared with PE 8214 had a hardness of 52.7–58.3 HRC. The microhardness of the matrix material was in the range of 573.3–893.0 HV, while that of the carbides was in the range of 2128.7–2436.3 HV. The abrasive wear resistance of the mild steel was improved after deposition of hardfaced layers by up to 5.7 times that of abrasion-resistant heat-treated steel, Hardox 400, having a nominal hardness of approximately 400 HV. The hardness and wear resistance were increased upon addition of Cr as an alloying element. Increasing the PGFR increased the hardness and wear resistance of the hardfacings, as well as increasing the number of surface cracks. Increasing the plasma transferred arc (PTA) current resulted in hardfacings with fewer cracks but lowered the wear resistance.

4

Fabrication and amplified spontaneous emission behavior of FAPbBr3 perovskite quantum dots in solid polymer rods

Khan M. Naziruddin, Almohammedi Abdullah

Materials Science Poland

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2022

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Vol. 40, No. 1

84--100

EN

Formamidinium lead tribromide (FAPbBr3) perovskite quantum dot (PQ-Dot) solution was incorporated in a polymer sol, which was used to fabricate solid nanocomposite rods and disks. The solid nanocomposite samples were studied by different characterization techniques. The absorption, emission, and excitation spectra of the PQ-Dot in the solid rods/disks were quite significant as compared to the spectra of the PQ-Dot solution. Scanning electron microscopy (SEM) was used to inspect the structural morphology of the PQ-Dot in the solid environment. The PQ-Dot particles were evidently present in the solid matrix and were confirmed by the SEM images and energy dispersive X-ray spectroscopy (EDX) spectra. The size of the PQ-Dots was examined by transmission electron microscopy (TEM). The majority of the particles were about 3–8 nm in size. The spontaneous and stimulated emission profiles of the solid composite rods/disks were studied using pumping energy ranging from 2 μJ to 18 μJ from a high-power picosecond neodymium-doped yttrium aluminum garnet (Nd:YAG) tunable laser system. The observed emission signal was quite significant. The emission peak of the PQ-Dot solution had a slight change when it was included in the solid matrix. Amplified spontaneous emission (ASE) behavior was obtained from the PQ-Dot composite rod. The ASE peaks were quite steady at different levels of excitation energy. ASE was achieved at low threshold energy. The composite rod with ASE behavior indicates that it is a promising composite material that can be used to achieve lasing in the future. The ASE obtained from the composite rods/disks may improve to achieve lasing if a high concentration of PQ-Dot solution is used in the matrix.

5

Effect of the Chemical Unhairing Process on Pulled Wool Characteristics

Abdellaoui Olfa, Harizi Taoufik, Msahli Slah

Fibres & Textiles in Eastern Europe

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2022

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Vol. 30, no. 3

70--78

EN

Textile research is being driven to find sustainable materials as an alternative to raw fibers. In fact, reusing fibrous waste, as a byproduct, is one of the most important environmental challenges that confront the world. This research focused on studying pulled wool fibers as a natural fiber to reduce environmental loading. There are large amounts of residual pulled wool fibers that can be recycled and valorised. Therefore, raw and pulled wool fibers were characterized and compared. Scanning Electron Micrographs (SEM) results show that on the pulled wool fiber, the surface became rougher and the scales appear affected and less dense. Based on the X-ray diffraction (XRD) results, the crystallinity of the pulled fiber decreased lightly. Attenuated Total Reflectance-Fourier Transform Infra Red (ATR-FTIR) spectroscopy analyzes presented some changes in chemical composition. A High-Performance Liquid Chromatography (HPLC) test showed an increase in the amount of cystic acids. The pulled wool fiber indicates that it might have damaged some crosslinks of macromolecular chains in the fiber. Thus, physical, chemical and mechanical properties are affected during the chemical unhairing process. This research purpose was to increase the potential for better value of pulled wool as it presents the natural fiber most used in several applications.

6

Biological and mechanical research of titanium implants covered with bactericidal coating

Malisz Klaudia, Świeczko-Żurek Beata

Engineering of Biomaterials

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2022

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vol. 25, no. 165

17--22

EN

Materials used in bone implants should not only be non- -toxic to the surrounding tissues, but also should promote osseointegration and minimize the risk of infection. Infections are a serious problem contributing to implantation failure. They are associated with pain, immobilization, and the necessity of reoperation. In extreme cases, they can lead to significant inflammatory changes in the bones, which, in turn, can lead to amputation and even death. After implantation, the surrounding tissues are damaged. In addition, implants are susceptible to bacterial colonization due to the lack of microcirculation. Therefore, scientists are working on antibacterial coatings to prevent the adhesion of bacteria before tissue regeneration. The paper concerns the biological and mechanical properties of titanium implants with an antibacterial coating. The Ti13Zr13Nb alloy samples were coated with hydroxyapatite (HAp) coatings using the electrophoretic deposition technique (EPD). Subsequently, the surface of the samples was modified with silver, copper, and nickel nanoparticles by the immersion method. Different titanium sample types (i.e. HAp-only and nanometals-enriched coatings) were placed in a bacterial solution for a period of one month. Each sample was examined using scanning electron microscopy (SEM), nanoindentation, nanoscratch, and contact angle tests. The significant amount of dead biofilm on the surface proves the effectiveness of antibacterial activity. The wettability assessment showed that the samples were hydrophilic. The conducted tests of mechanical properties indicate the heterogeneity of the coatings.

7

Compression behaviour of BFRP bars

Urbański Marek, Protchenko Kostiantyn

Archives of Civil Engineering

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2022

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Vol. 68, nr 3

257--271

EN

The durability of building structures reinforced by steel is one of the main concerns in civil engineering. Currently, research in the field is focused on the possibility of replacing steel with relatively corrosion-resistant reinforcement, such as BFRP (Basalt Fiber Reinforced Polymers) bars. The behaviour of BFRP bars during compression has not yet been determined. The experimental results pertaining to BFRP bars subjected to compression were presented and discussed in the paper. The research program involved the preparation of 45 BFRP samples with varying unbraced length and nominal diameter of 8 mm that were subjected to compression. For samples with the unbraced length of up to 85 mm, the destruction was caused by crushing. The bars with the unbraced length greater than 120 mm were destroyed as a result of global buckling of the bar and subsequent fiber kinking. Based on the relationship between the buckling load strength - unbraced length, the optimal unbraced length of BFRP bar was determined, for which buckling load strength reaches its maximum value. The buckling load strength decreased, as the unbraced length increased. The values of modulus of elasticity under compression for variable unbraced lengths were slightly different for the samples, and were similar to the modulus of elasticity obtained at the tensile testing. The relationship between the buckling load strength and the unbraced length of BFRP bars was determined. This may contribute to the optimization of the transverse reinforcement spacing in compressed elements and to the development of standard provisions in the area of elements reinforced with FRP bars being subjected to compression.

PL

Obecnie niezwykle dynamicznie rozwija się zastosowanie materiałów kompozytowych o wysokich parametrach użytkowych takich jak pręty BFRP (Basalt Fiber Reinforced Polymers) jako zamiennika tradycyjnego zbrojenia stalowego w budownictwie. W artykule przedstawiono ocenę wytrzymałości na obciążenie wyboczeniowe prętów BFRP, co umożliwia ich wykorzystanie, jako zbrojenia w betonowych elementach ściskanych (słupy) oraz w strefie ściskanej elementów zginanych (np. belki i płyty). W porównaniu ze zbrojeniem stalowym, pręty BFRP mają kilka istotnych zalet. Są to między innymi mały ciężar, wysoka wytrzymałość na rozciąganie, odporność na korozję, przezroczystość na pola magnetyczne. Natomiast w porównaniu do najbardziej rozpowszechnionych prętów GFRP (Glass Fiber Reinforced Polymers) wykazują zdecydowanie większą odporność na alkalia i kwasy. Włókna bazaltowe nie reagują toksycznie z powietrzem, wodą ani innymi chemikaliami, które mogą być niebezpieczne dla ludzi lub mogą zanieczyścić środowisko. Ponadto włókna bazaltowe nie są rakotwórcze. W trakcie recyklingu włókna przekształcają się w czarny proszek, który można łatwo usunąć z komory spalania i można go wykorzystać jako wypełniacz do różnych zastosowań. Przeprowadzono jakościową i półilościową analizę składu pierwiastkowego przy użyciu spektrometru dyspersji energii wtórnego promieniowania X (EDS) które dostarczyły istotne informacje dotyczące składu prętów BFRP. We włóknach bazaltowych stwierdzono, obecność dominujących związków SiO2 i Al2O3, które występują także we włóknach szklanych. Ponadto odnotowano obecność związków żelaza Fe2O3 i FeO mających wpływ na fizyko-mechaniczne właściwości włókien bazaltowych, takich jak gęstość (2,73 g/cm3 dla włókien bazaltowych, w porównaniu do 2,54 g/cm3 dla włókien szklanych typu E), kolor (od brązowego do matowo zielonego, w zależności od zawartości FeO), a także mniejsze przewodnictwo cieplne i lepsza stabilność temperaturowa w porównaniu z włóknami szklanymi. Ustalono w badaniu metodą BSE konfigurację oraz niewielki rozrzut w średnicach włókien bazaltowych wchodzących w skład pręta BFRP. Zachowanie prętów BFRP podczas ściskania dotychczas nie zostało określone. W programie badawczym zbadano 45 próbek BFRP o nominalnej średnicy 8 mm ze względu na ściskanie o zróżnicowanej długości niezakotwionej. Dla próbek o długości niezakotwionej do 85 mm zniszczenie następowało przez zgniatanie. Pręty o długości niezakotwionej większej od 120 mm ulegały zniszczeniu w wyniku globalnego wyboczenia pręta a następnie pękania włókien. Na podstawie zależności wytrzymałość na obciążenie wyboczeniowe - niezakotwiona długość pręta ustalono optymalną długość niezakotwioną pręta BFRP, dla której wytrzymałość na obciążenie wyboczeniowe osiąga największą wartość. Wraz ze wzrostem długości niezakotwionej wytrzymałość na obciążenie wyboczeniowe ulegała zmniejszeniu. Moduł sprężystości przy ściskaniu dla zmiennych długości niezakotwionych próbek nieznacznie się różnił, a jego wartość zbliżona była do modułu sprężystości przy rozciąganiu. Określono zależność między wytrzymałością na obciążenie wyboczeniowe a długością niezakotwioną prętów BFRP, co przyczyni się do optymalizacji rozstawu zbrojenia poprzecznego w elementach ściskanych oraz do opracowania przepisów normowych w obszarze elementów ze zbrojeniem ściskanym.

8

Porosity assessment of suspension and saturated composite castings with the use of microscopic examinations

Staude Marek

Zeszyty Naukowe Akademii Morskiej w Szczecinie

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2021

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nr 67 (139)

53--57

EN

Good quality in composite castings can be confirmed primarily by their user. The producer is obliged to create a good product that meets the user’s needs that should undergo quality control. Omission of technological procedures and improper quality control may result in various defects like porosity. This paper presents the characteristics of the casting defect, namely porosity, with a particular focus on porosity in suspension and saturated metal composites. This defect is different, specific to composite castings, making its identification very difficult. The aim of the study is to detect and describe porosity in composites with the use of microscopic and submicroscopic examinations. The assessment of the porosity of the microstructure of composite castings allowed for the formulation of the following conclusions: in addition to the porosity that occurs in castings of classic materials (cast steel, cast iron, and non-ferrous metal alloys), metal composites also distinguish between primary and secondary agglomerates, leaving the reinforcement space not filled, occluded bubbles, and separated gas bubbles.

9

Działanie czynników mechanicznych oraz termicznych na morfologię włosów ludzkich i zwierzęcych

Dobosz Magda, Kalska-Szostko Beata

Wiadomości Chemiczne

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2021

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[Z] 75, 5-6

823--844

EN

The main purpose of the presented study was to investigate and compare the influence of mechanical and thermal factors on the morphology of human and animal hair. Several factors that may occur during criminal offenses were selected for testing including cutting by a scalpel or scissors, damaging by a hammer; and high, or low-temperature thermal treatment (heating for 1h, or 24 hours at elevated temperatures 100°C, 200°C, and 300°C, as well as freezing for 24 hours at -20°C, or for 10 minutes in liquid nitrogen (-197°C)). The impact of selected mechanical and temperature factors on human and animal hair was made mainly on the basis of Scanning Electron Microscopy (SEM). Moreover, the elemental composition of the hair was investigated and analyzed using an EDX (Energy - Dispersive X-ray) spectrometry. Performed tests show the degree of human hair degradation depending on the examined factor and time.

10

Correlation of manufacturing defects and impact behaviors of kenaf fiber reinforced hybrid fiberglass/Kevlar polyester composite

Suriani M. J., Sapuan S. M., Ruzaidi C. M., Naveen J., Syukriyah H., Ziefarina M.

Polimery

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2021

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T. 66, nr 1

30--35

PL

Zbadano udarność hybrydowego kompozytu polimerowego na osnowie żywicy poliestrowej napełnionej włóknami szklanymi i kevlarowymi wzmocnionego włóknem łykowym kenaf. Wytworzono pięć próbek różniących się zawartością włókien kenafu (0, 15, 45, 60 i75% obj.) Próbkę kontrolną stanowił kompozyt z 0% obj. udziałem włókien kenaf (0%). Wykazano, że hybrydyzacja wpłynęła na poprawę właściwości udarowych wyjściowego kompozytu. Wyniki potwierdzono analizą SEM defektów produkcyjnych otrzymanego kompozytu. Stwierdzono, że zachodzi korelacja między wytrzymałością na uderzenie awadami produkcyjnymi badanego hybrydowego kompozytu poliestrowego wzmocnionego włóknami kenaf. Powstałe podczas produkcji wady produkcyjne wistotnym stopniu pogarszają właściwości udarowe kompozytów.

EN

In this study, the impact properties of kenaf fibre reinforced hybrid fiberglass/Kevlar polymeric composite was investigated. In this study, a new fiber arrangement based on kenaf bast fiber as reinforcement to the hybrid fiberglass/Kevlar fiber and polyester as matrix used to fabricate the hybrid polymeric composite. Five different types of samples with different of kenaf fiber content based on volume fraction (0, 15, 45, 60 and 75%) to hybrid fiberglass/Kevlar polymer composites were manufactured. 0% of kenaf fiber has been used as control sample. The results showed that hybridization has improved the impact properties. These results were further supported through SEM micrograph of the manufacturing defects of the polymer composite. Based on literature work, manufacturing defects that occurs in composite system reduced the mechanical properties of the material. Therefore, in this research the correlation of impact behaviors and manufacturing defects of kenaf fiber reinforced hybrid fiberglass/Kevlar polymeric composite has been successfully done. As conclusion, the highest manufacturing defects determined in the composites during the fabrication significantly lowest the results of impact behavior.

11

Impaktor kaskadowy jako metoda poboru nanoobiektów do analizy mikroskopowej

Kozikowski Paweł, Sobiech Piotr, Oberbek Przemysław, Jakubiak Szymon

Podstawy i Metody Oceny Środowiska Pracy

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2021

|

Nr 2 (108)

155--167

PL

Pył zawieszony może być szkodliwy dla zdrowia ludzkiego, a ryzyko wystąpienia szkodliwych skutków zwiększa się z czasem narażenia. Obecnie grupami zawodowymi potencjalnie narażonymi na działanie nanomateriałów są ci, którzy je wytwarzają i dostarczają. Dlatego konieczne jest stosowanie urządzeń do zbierania i analizy cząstek stałych z wyłączeniem frakcji mikrometrycznej. W pracach badawczych pobierano cząstki zawarte w spalinach z silnika wysokoprężnego przy użyciu impaktora kaskadowego i analizowano z zastosowaniem skaningowej mikroskopii elektronowej. Obserwacje ujawniły duże rozbieżności między średnicami odcięcia d50 a średnicami ekwiwalentnymi obliczonymi na podstawie obrazów SEM, a także różnorodną morfologię zdeponowanych cząstek stałych pochodzących z silnika Diesla. Zakres tematyczny artykułu obejmuje zagadnienia zdrowia oraz bezpieczeństwa i higieny środowiska pracy będące przedmiotem badań z zakresu nauk o zdrowiu oraz inżynierii środowiska.

EN

Particulate matter can be harmful to human health and the risk of harmful effects increases with the duration of exposure. Currently, the occupational groups that are potentially exposed to nanomaterials are those who manufacture and supply them. Therefore, it is necessary to use devices for the collection and analysis of solid particles with the exclusion of the ambient fraction. In this study, Diesel soot generated using Diesel engine has been collected with cascade impactor and analyzed by means of scanning electron microscopy. Observations revealed large discrepancies between the cut off diameter d50 and equivalent diameter calculated from SEM images and a number of types of Diesel particulate matter. This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering.

12

Skaningowa analiza grubości i ciągłości warstw tynków elewacyjnych w zewnętrznym zespolonym systemie ocieplania ścian ETICS

Jasiczak Józef, Gaczek Mariusz, Kanoniczak Marcin

Materiały Budowlane

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2021

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nr 9

20--23

PL

Popularne systemy ocieplania ścian zewnętrznych składają się z dwóch podstawowych warstw: termoizolacyjnej i wierzchniej – dekoracyjno-ochronnej, nakładanej na materiał do izolacji cieplnej. Termoizolację łączy się z ocieplaną ścianą najczęściej przez: przyklejenie przy użyciu zaprawy klejącej, masy klejącej albo kleju poliuretanoweg oraz zamocowanie przy użyciu łączników mechanicznych. Warstwą mającą kontakt z otoczeniem zewnętrznym jest tynk cienkowarstwowy, którego grubość przyjmuje się z przedziału od 1 do 5 mm w zależności od oferowanego na rynku systemu. Technologia wykonywania ocieplenia nie jest skomplikowana, jednak z praktyki budowlanej wynika, że w trakcie eksploatacji ujawniają się różne wady tynków, a przyczyna ich wystąpienia często nie jest jednoznaczna. Autorzy artykułu, po wykonaniu wielu ekspertyz warstw elewacyjnych budynków, chcieliby zwrócić uwagę na strukturę wewnętrzną tynku cienkowarstwowego i jego nieciągłości, by szukać w nich przyczyn występujących wad.

EN

Popular external wall insulation systems consist of two basic layers: thermal insulation and rendering system, connected to the insulated wall by means of adhesive layer and mechanical fasteners. The contact layer with the surroundings is a finishing coat, the thickness of which ranges from 1 to 5 mm, depending on the system offered on the market. The technology of wall insulation is not complicated, but construction practice shows, that many finishing coat defects are revealed during the exploitation, and the reason for their occurrence is not clear. The authors of the article, after making many expert opinions of the rendering systems of buildings, would like to draw attention to the internal structure of the thin-layer plaster and its discontinuities, in order to look for the causes of the defects in them.

13

In situ-formed bacterial exopolysaccharide (EPS) as a potential carrier for anchorage-dependent cell cultures

Komorowski Piotr, Kołodziejczyk Agnieszka, Makowski Krzysztof, Kotarba Sylwia, Walkowiak Bogdan

Engineering of Biomaterials

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2021

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Vol. 24, no. 159

18--23

EN

The study involved the use of a bacterial strain isolated from environmental samples which produce the biopolymer in the form of pellets in the submerged culture. This material (bacterial exopolysaccharide) is produced by bacteria of the Komogateibacter xylinus which are prevalent in the environment. The aim of this study was to characterize bacterial exopolysaccharides and commercial dextran-based “microcarriers” in terms of their roughness and cell culture effects, including the morphology and viability of the human hybridoma vascular endothelial cell line EA.hy926. The pellets were characterized using scanning electron microscopy (SEM) and atomic for¬ce microscopy (AFM). The resulting structures were used for cell culture of adherent cells (anchorage¬-dependent cells). At the same time, the cultures with commercial, dextran-based “microcarriers” were carried out for comparative purposes. After com¬pletion of the cell culture (24 hours of culture), the cellulose and commercial “carriers” were analyzed using SEM and AFM. Finally, the obtained cell dens¬ities (fluorescence labelling) and their morphological characteristics (SEM) were compared. The obtained results strongly support the applicability of bacterial exopolysaccharide (EPS) in tissue engineering to build innovative 3D scaffolds for cell culture, the more so that it is technologically possible to produce EPS as spatially complex structure

14

Understanding technical cleanliness: importance, assessment, maintenance

Faber Joanna, Brodzik Krzysztof, Nycz Marta

Combustion Engines

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2021

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R. 60, nr 3

41--50

EN

Development of the automotive industry, including so-called dowsizing and rightsizing, entails the need to ensure, and hence to verify, the stringent cleanliness levels of an increasing number of car components. The assurance of proper cleanliness level requires knowledge of the entire production process and precise information on the contaminants that will allow to identify their sources. Obtaining reliable cleanliness information requires establishing of many different factors, i. a. selection of proper contamination extraction and collection technique, proper parameters of extraction, validation of extraction procedure, methods of particles analysis. Analytical techniques which are implemented include gravimetric, optical microscopy and advanced techniques like scanning electron microscopy. This work present’s actual state of knowledge regarding technical cleanliness analysis of components. Important aspects of QA&QC in technical cleanliness assessment are also discussed.

15

Fabrication and characterization of Zr microplasma sprayed coatings for medical applications

Voinarovych Sergii G., Alontseva Darya L., Kyslytsia Oleksandr N., Kaliuzhnyi Sergii, Khozhanov Alexandr R., Krasavin Alexander, Kolesnikova Tatiana

Advances in Materials Science

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2021

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Vol. 21, nr 2(68)

93--105

EN

This paper presents new results of studying the influence of parameters of microplasma spraying (MPS) of Zr wire on the structure of Zr coatings. The coating experiments were accomplished in a two level fractional factorial design. Individual particles of sprayed Zr wire and their splats on the substrate were collected under various spraying parameters (amperage, spraying distance, plasma gas flow rate and wire flow rate) and evaluated by Scanning Electron Microscopy (SEM) to establish the effect of particle size and shape on the coating microstructure. The particles were characterized by measurement of their sizes and the obtained results were evaluated in terms of their degree of melting. This was compared with the experimentally observed coating microstructure type and finally correlated to the investigated coating porosity to select the specific MPS parameters of Zr coatings depositing onto medical implants from Ti alloy. It was found that the main parameters influencing the size of the sprayed Zr particles and the porosity of the Zr coatings are the plasma gas flow rate and amperage. It was demonstrated that it is possible to control the porosity of Zr microplasma coatings in the range from 2.8% to 20.3% by changing the parameters of the MPS. The parameters of microplasma spraying of Zr wire were established to obtain medical implant coatings with porosity up to 20.3% and pore size up to 300 μm.

16

Wpływ czynników chemicznych na strukturę i budowę włosów ludzkich

Dobosz Magda, Kalska-Szostko Beata

Wiadomości Chemiczne

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2020

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[Z] 74, 7-8

453--476

EN

The main purpose of the presented study was to investigate the influence of chemical factors on the morphology of human hair. Few factors that may occurduring criminal offenses were selected for testing, including aqueous solutions of hydrochloric acid (HCl), sodium hydroxide (NaOH), lead(II) nitrate (Pb(NO3)2), cadmium(II) nitrate (Cd(NO3)2), sodium chloride (NaCl), ethanol (C2H5OH), water (H2O). The description of the effects of chosen chemical compounds on hair was made mainly on the basis of Scanning Electron Microscopy (SEM). In addition, the elemental composition of the hair as an effect of interaction with solution was examined and analyzed using an EDX (Energy - Dispersive X-ray) spectrometry. Performed tests show the degree of human hair degradation and contamination depending on the examined factor and time.

17

Metody mikroskopowe w ocenie procesów wykończania wyrobów włókienniczych

Machnowski Waldemar, Wrzosek Henryk

Technologia i Jakość Wyrobów

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2020

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R. 65

4--20

PL

Badanie wyrobów włókienniczych odgrywa istotną rolę w systemie zapewnienia jakości tekstyliów, a także w pracach nad rozwojem nowych technologii i produktów włókienniczych. Istnieje wiele metod oceny struktury i właściwości włókien i wyrobów włókienniczych. Bardzo ważne miejsce wśród tych metod zajmują techniki mikroskopowe, w szczególności mikroskopia optyczna i skaningowa mikroskopia elektronowa (SEM). W artykule podano krótki przegląd możliwych zastosowań metod mikroskopowych do analizy efektów niektórych operacji wytwarzania tekstyliów. Wykorzystanie mikroskopu optycznego umożliwiło identyfikację przyczyn powodujących nierównomierność barwy wyrobów bawełnianych. Z przeglądu literatury oraz doświadczeń własnych autorów wynika, że metody mikroskopowe stanowią cenne narzędzie w badaniu włókien i wyrobów włókienniczych.

EN

Fabric testing plays an important role in the quality assurance system and in the development of new textile technologies and products. There are many test methods used to evaluate the structure and properties of fibers and textile materials. Among these methods, microscopic techniques – especially optical microscopy and scanning electron microscopy (SEM) – are one of the most important methods. This paper provides a brief overview of the possible uses the microscopic methods for determining the results of some textile manufacturing processes. A review of the literature and the authors experiences in this field indicate that microscopic methods are a valuable tool for the testing and assessing the performance of fibers and textile products.

18

Characterisation of Mg-Zn-Ca-Y powders manufactured by mechanical milling

Lesz S., Tański T., Hrapkowicz B., Karolus M., Popis J., Wiechniak K.

Journal of Achievements in Materials and Manufacturing Engineering

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2020

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Vol. 103, nr 2

49--59

EN

Purpose: This paper explains mechanical synthesis which uses powders or material chunks in order to obtain phases and alloys. It is based on an example of magnesium powders with various additives, such as zinc, calcium and yttrium. Design/methodology/approach: The following experimental techniques were used: X-ray diffraction (XRD) method, scanning electron microscopy (SEM), determining particle size distributions with laser measuring, Vickers microhardness. Findings: The particle-size of a powder and microhardness value depend on the milling time. Research limitations/implications: Magnesium gained its largest application area by creating alloys in combination with other elements. Magnesium alloys used in various industry contain various elements e.g. rare-earth elements (REE). Magnesium alloys are generally made by casting processes. Consequently, the search for new methods of obtaining materials such as mechanical alloying (MA) offers new opportunities. The MA allows for the production of materials with completely new physico-chemical properties. Originality/value: Thanks to powder engineering it is possible to manufacture materials with specific chemical composition. These materials are characterized by very high purity, specified porosity, fine-grain structure, complicated designs. These are impossible to obtain with traditional methods. Moreover it is possible to refine the process even further minimalizing the need for finishing or machining, making the material losses very small or negligible. Furthermore material manufactured in such a way can be thermally or chemically processed without any problems.

19

A study on alkali resistant glass fibre concrete and its exposure to elevated temperatures

Hussain S., Yadav J. S.

Journal of Achievements in Materials and Manufacturing Engineering

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2020

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Vol. 103, nr 1

5--15

EN

Purpose: Cement concrete is characterized as brittle in nature, the loading capacity of which is completely lost once failure is initiated. This characteristic, which limits the application of the material, can in one way be overcome by the addition of some small amount of short randomly distributed fibers (steel, glass, synthetic). Design/methodology/approach: The present study deals with the inclusion of alkali resistant glass fibers in concrete by percentage weight of cement. The mechanical properties such as compressive strength and split tensile strength have been studied after exposing the concrete samples to elevated temperatures of up to 500°C. Water binder ratios of 0.4, 0.45, 0.5, 0.55 and 0.6 have been used to prepare design mix proportions of concrete to achieve a characteristic strength of 30 MPa. The depth of carbonation post elevated temperature exposure has been measured by subjecting the concrete samples to an accelerated carbonation (5%) condition in a controlled chamber. Findings: Conclusions have been drawn in accordance to the effect of fiber replacement and temperature increment. The concrete mixes with fiber content of 1% by weight of cement had shown better strength in compression and tension compared to the other dosages and conventional concrete (without fiber). Microcracking due to internal stream pressure reduced the mechanical strengths of concrete at elevated temperatures. Also, from TGA it was observed that the amount of calcium carbonate in samples with fiber added, post carbonation was less than the mixes without fiber in it. Research limitations/implications: The present study has been limited to alkali resistant glass fibers as the conventional glass fibers undergo corrosion due to hydration. Practical implications: The glass fiber reinforced concrete can be used in the building renovation works, water and drainage works, b ridge and tunnel lining panels etc. Originality/value: Based upon the available literature, very seldom the studies are addressing the behaviour of alkali resistant glass fiber concrete and its exposure to elevated temperatures.

20

Microscopic analysis of the nanostructures impact on endothelial cells

Kołodziejczyk Agnieszka Maria, Kucińska Magdalena, Jakubowska Aleksandra, Siatkowska Małgorzata, Sokołowska Paulina, Kotarba Sylwia, Makowski Krzysztof, Komorowski Piotr, Walkowiak Bogdan

Engineering of Biomaterials

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2020

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Vol. 23, no. 154

2--8

EN

Nowadays nanostructures are more and more often designed as carriers for drug delivery, especially to improve the drug pharmacokinetics and pharmaco-dynamics. Numerous kinds of nanostructures are considered a good prospect for medical applications thanks to their small size, acceptable biocompatibility and toxicity. Due to the fact that nanotechnology is a new field of science, every nano-scale product must be thoroughly examined regarding its toxicity to the human body. This study provides new insights into effects of exposing endothelial cells to the selected nanostructures. Dendrimers of the fourth generation (PAMAMs), multi-walled carbon nanotubes (MWCNTs) and silver nanoparticles (SNPs) were used to evaluate nanostructures influence on endothelial cells in vitro. The nanostructures were evaluated via transmission electron microscopy and dynamic light scattering technique. The cells previously exposed to the nanostructures were observed and analyzed via the atomic force microscopy and scanning electron microscopy to obtain a quantitative evaluation of the cells morphology. The presence of multi-walled carbon nanotubes and silver nanoparticles on the cells surface was confirmed by the scanning electron microscopy. Our results confirm that the surface association and/or uptake of nanostructures by the cells resulting from physicochemical and biological processes, affect the cells morphology. Morphological changes can be induced by the membrane proteins interaction with nanomaterials, which trigger a sequence of intracel-lular biological processes.