Wyniki wyszukiwania - BazTech

1

The design and optimization of the mixing process for Udimet 720LI nickel alloy manufacturing from elemental powders

Skonieczna Wiktoria, Wojtaszek Marek, Lypchanskyi Oleksandr, Cichocki Kamil, Goły Marcin, Kopyściański Mateusz, Zientara Dariusz, Stanik Rafał, Gude Maik, Prahl Urlich

Advances in Science and Technology. Research Journal

|

2025

|

Vol. 19, no. 3

1--11

EN

The objective of the study was to design an efficient production route for the U720LI nickel alloy using elemental powders as initial materials. The powder mixing process was carried out using a double-cone mixer and an Attritor mill, respectively. A device proper for effective mixing and mechanical alloying of powder particles was selected, and the most favorable parameters for the powder mixing process necessary for the production of the alloy were developed. The analysis of the results showed that significantly higher efficiency in mixing the powders necessary for producing the U720LI alloy was achieved using the Attritor mill. In further tests, the most favorable operating parameters of this device were determined by mixing materials at different rotational speeds. The results demonstrated that the most effective method of powder bonding among the tested variants was mixing in the Attritor mill at the identified high rotational speeds. A highly densified product with a homogeneous microstructure and free of external and internal defects was obtained, suitable for use both as a finished product and as high-quality feedstock for hot metal forming processing.

2

Evaluation of the mechanical performance of iron- polymethyl methacrylate and polystyrene polymer products based on alumina nanomaterials

Mohamed Muzher Taha, Nawi Sami A., Algailani Hiba M., Alrubaiy Ahmed A.A.G., Mahmoud Adel K., Farman Salem, Mustafa Ali Mundher, Alamiery A.A.

Advances in Science and Technology. Research Journal

|

2025

|

Vol. 19, no. 3

202--210

EN

In this investigation, alumina (Al₂O₃) nanoparticles were utilized to study the mechanical properties of two polymer nanocomposite systems applied to low-carbon steel substrates. The nanocomposites comprised polystyrene (PS) and polymethylmethacrylate (PMMA) matrices, each incorporating 5 wt.% Al₂O₃ nanoparticles. Tensile tests revealed that the nanocomposites exhibited superior mechanical performance compared to pure polymers. For PMMA-Al₂O₃, tensile properties such as elastic modulus (E), ultimate tensile strength (σₐᵤₗₜ), and strain (eᵤₗₜ) were 2.6326 GPa, 44.52 MPa, and 0.02560, respectively, showing improvements of 16.5% in σₐᵤₗₜ and 33.7% in eᵤₗₜ. Similarly, PS-Al₂O₃ showed σₐᵤₗₜ and eᵤₗₜ improvements of 19.1% and 61.5%, respectively, compared to pure PS. The Scanning electron microscopy (SEM) revealed flocculation and uneven nanoparticle dispersion. At low magnification (1.56 µm), PS-Al₂O₃ particles were well-separated, while higher magnification (11.6 µm) showed aggregation. The average nanoparticle diameters for PMMA-Al₂O₃ and PS-Al₂O₃ were 201.1 nm and 184.6 nm, respectively. Flocculation and low-density interphase, attributed to fewer polymer chain anchoring sites on Al₂O₃ surfaces, reduced the elastic modulus. These findings emphasize the need for advanced blending techniques to achieve uniform nanoparticle distribution and improve polymer-nanoparticle interfacial bonding. Optimized dispersion methods are crucial for enhancing the mechanical properties of Al₂O₃-reinforced nanocomposites

3

DOCOL 1100M welding in the construction of electric means of transport

Szczucka-Lasota Bożena, Gołombek Klaudiusz, Węgrzyn Tomasz, Łazarz Bogusław, Lukaszkowicz Krzysztof, Pereira Silva Abilio, Antczak-Jarząbska Romana

Transport Problems

|

2024

|

T. 19, z. 2

219--228

EN

Advanced high-strength steels are important for the automotive sector. Metal active gas (MAG) is the most popular method for joining grades of steel. The goal of the paper is to analyze the mechanical properties of the MAG welding joint made of high-strength DOCOL 1100M intended for the construction of electric vehicles. The manuscript shows a basic understanding of the properties of DOCOL joints. This type of material is characterized by a martensitic microstructure, which makes it difficult to make a proper joint. The tensile strength, metallographic structure, and type of non-metallic inclusions were analyzed as a function of the oxygen amount in the protective gas mixture. Investigations of oxide non-metallic inclusions were carried out using scanning electron microscopy. This article attempts to obtain high joint strength of the electric vehicle structure by controlling the average size of non-metallic inclusions in the weld, which is influenced by shielding gas in the MAG welding process. The solution has application potential for the automotive industry, especially for electric vehicles.

4

Study the Effectiveness of Household Water Filtration Systems in Eliminating Plastic Particles in Mosul City, Iraq

Altaee Raghad N., Al-Ahmady Kossay K., Mhemid Rasha Khalid Sabri

Journal of Ecological Engineering

|

2024

|

Vol. 25, nr 9

24--33

EN

Plastic particles are considered a concerning issue on a global scale. This research aimed to examine the existence and features of microplastics (MPs) as well as evaluate the removal efficiency (RE%) of household water filter systems (HWFS). The research was conducted in 12 areas distributed across Mosul City. Various techniques, including Fourier transform spectroscopy (FTIR), stereomicroscopy, and scanning electron microscopy (SEM), were employed to accurately detect the presence of microplastics, analyze morphological properties, such as color, shape, and size, and determine the polymer types. The research findings showed that the efficiency of HWFS ranged from 93% to 30%, affected by several factors, including filter age and the number of its stages. Fibers and fragments were the most commonly encountered shapes of MPs accounting for about 94% of the examined instances. Around 52% of the total was characterized by a transparent color. An estimated 35% of MPs sizes were smaller than 10 µm. Out of all considered polymer types, polyvinyl chloride (PVC) represented the highest percentage, around 58%. Moreover, PVC was found to have a higher risk index compared to other types of polymers.

5

Reactive Magnetron Sputtering Technology for Receiving III Nitrides

Kushitashvili Zurab, Bibilashvili Amiran, Dolidze Nugzar, Skhiladze Givi, Guliaevi Revaz

Inżynieria Mineralna

|

2024

|

Vol. 1, no. 1

675--680

EN

In the present work is studied synthesis of galium nitride (GaN) and aluminum nitride (AlN) by DC Reactive Magnetron Sputtering technology. As a sputtering target was used high purity (99.9999%) Gallium and Aluminum materials and as a reagent gas was used high purity (99.9999%) Nitrogen. Magnetron sputtering system with strong magnets (1450 mT) allows to make plasma at a low preasure 3 × 10-2 Pa and deposition process was carried out at high vacuum conditions. Deposited layers of GaN and AlN on the sappire substrate was analysed by X-ray diffraction (XRD) and revealed the crystalline nature highly oriented with the (0002) for both nitrides. For chemical composition was measured X-ray Photoelectron Spectroscopy (XPS) and it was found out the ratios of Ga:N and Al:N to be 1.07 and 1.04 respectively. For surface analysis was made Scanning Electron Microscopy (SEM). Optic transmission spectra showed band gaps to be 3.43 eV and 6.13 eV for GaN and AlN respectively.

6

The use of scanning electron microscopy in the study of the components of Zn-Pb slags on the example of slags from the dump in Bykowina (Ruda Śląska)

Jonczy Iwona, Filipowicz Krzysztof

Gospodarka Surowcami Mineralnymi

|

2024

|

T. 40, z. 2

89--119

EN

Scanning electron microscopy (SEM) enables the obtaining of high-resolution images of sample surfaces by recording secondary electrons (SE) or backscattered electrons (BSE) characterized by depth of field and high resolution. Observations using scanning electron microscopy are widely used in many fields of science. The authors show that scanning electron microscopy is also one of the key technique used in the study of the metallurgical slags components. The research was performed for three types of slag following the production of Zn and Pb collected from an old dump in Ruda Śląska – Bykowina. The slag components were identified, morphology and chemical composition of the crystalline phases were characterized and the chemical composition of glaze was determined. Based on observations using secondary electrons, two areas with diverse morphology were identified in slag resulting from the production of cast iron: fragments with coarse structure and visible crystallites of phase components, and a vitrified material with a smooth, non-fractured surface and numerous regular- and round-shaped pores. It was found that in the surroundings of the dominant glaze (rich mainly in Si, Ca and Al) in all types of slags, well-developed crystals of phase components can be distinguished: in slag no. 1, these are Fe-Mg silicates; in slag no. 2, they are aluminosilicates of Ti and K; in slag no. 3, the presence of fine needle-shaped crystals containing Al and Si was found, which indicates the presence of mullite. During the storage in the dumping ground, numerous secondary minerals crystallize in the pores of the slag. Pores are the remains of the degassing of the slag melt during its cooling – hematite and barite were identified among them.

PL

Skaningowa mikroskopia elektronowa (SEM) pozwala uzyskać wysokorozdzielcze obrazy powierzchni próbek za pomocą rejestracji elektronów wtórnych (SE) lub elektronów wstecznie rozproszonych (BSE), charakteryzujące się głębią ostrości oraz wysoką rozdzielczością. Obserwacje przy wykorzystaniu skaningowej mikroskopii elektronowej znajdują szerokie zastosowanie w wielu dziedzinach nauki, autorzy pokazali, że skaningowa mikroskopia elektronowa to także jedna z kluczowych technik wykorzystywana w badaniach składników budujących żużle hutnicze. Badania przeprowadzono dla trzech rodzajów żużli po produkcji Zn i Pb pobranych ze starego zwałowiska w Rudzie Śląskiej – Bykowinie. Dokonano identyfikacji składników budujących żużle, scharakteryzowano morfologię faz krystalicznych, oznaczono ich skład chemiczny, jak również skład chemiczny szkliwa. Na podstawie przeprowadzonych obserwacji w żużlach wyróżniono dwa obszary o zróżnicowanej morfologii; obok fragmentów o chropowatej strukturze z widocznymi zarysami krystalitów składników fazowych, wyróżniono zeszklony materiał o gładniej, niespękanej powierzchni, w obrębie którego występują liczne pory o regularnych, okrągłych kształtach. Stwierdzono, że w otoczeniu dominującego szkliwa (bogatego przede wszystkim w Si, Ca i Al), we wszystkich rodzajach żużli można wyróżnić dobrze wykształcone kryształy składników fazowych: w żużlu nr 1 są to krzemiany Fe-Mg, w żużlu nr 2 – glinokrzemiany Ti i K, natomiast w żużlu nr 3 stwierdzono obecność drobnych kryształów o pokroju igiełkowym zawierających Al i Si, co wskazuje na obecność mullitu. Podczas składowania na zwałowisku, w porach żużli, stanowiących pozostałość po odgazowania stopu żużlowego w trakcie jego chłodzenia, licznie krystalizują minerały wtórne – zidentyfikowano wśród nich hematyt oraz baryt.

7

Characteristics and mineralogy of sediments in the Hongsa lignite deposit, northwestern Laos

Sattraburut Thunyapat, Thasod Yupa, Ratanasthien Benjavun, Vongvassana Sirasit

Geologos

|

2024

|

Vol. 30, No. 3

171--194

EN

Two sediment cores from the central part of the Hongsa lignite deposit in northwestern Lao PDR (Lao People’s Democratic Republic; Laos) have been analysed in order to understand their sedimentary characteristics using grain-size analysis, petrography, X-ray diffraction and scanning electron microscopy. This analysis has revealed that the deposit is primarily composed of fine-grained sediments, mainly silt and clay, with quartz as the dominant mineral and trace amounts of other minerals such as kaolinite, illite and montmorillonite. Gypsum and chlorite have also been found in some layers. Scanning electron microscope analysis has revealed a card-house structure of clay minerals, suggesting sedimentation from suspension driven by physico-chemical reactions influenced by pH and water chemistry. This arrangement increases porosity and water retention, significantly affecting the permeability and mechanical properties of sediments. Petrographic analysis has documented angular quartz and poorly sorted sediments, indicating minimal sediment reworking or short-distance sources. The palaeoenvironment of the Hongsa Basin, reconstructed from various rock units, suggests low-energy water conditions for the Underburden and moderate sediment supply in a wet forest swamp or bush moor environment for the Lower Lignite Zone Formation. The Middle Lignite Zone Formation indicates a more limited sediment supply in a similar environment, while Interburden Formation 1 suggests overbank deposits or stagnant water deposits. In summary, the Neogene Hongsa lignite deposit is characterised by fine-grained sediments, indicating low-energy water currents in mire environments. Occasional flood events brought coarser grains, although movement of facies should also be taken into account. The mineral composition suggests the presence of components derived from recycled sedimentary rocks along the northern border of the Hongsa Basin.

8

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

|

2023

|

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.

9

Investigation of silver nanoparticles embedded in extracted gelatins from camel, bovine, and fish bones for possible use in radiation dosimetry

Alrashidi Thaar K., Aljuhani Alwaleed, Almugaiteeb Faisal, Badi Nacer, Al-Aoh Hatem A., Alghamdi Saleh A., Alsharari Abdulrhman M., Alzahrani Ahmed Obaid M., Almalki Khaled

Materials Science Poland

|

2023

|

Vol. 41, No. 4

1--12

EN

Gelatins from camel, bovine, and fish bones were successfully extracted by using chemical pretreatment and heating methods. The bones were demineralized for 3 days at ambient temperature using hydrochloric acid solutions (0.5–1 M), and the collagen was partially hydrolyzed by preheating in distilled water at 75–80°C for 3 h, followed by extraction temperature at 90°C for 1 h. Free-standing films of gelatin entrained with silver nanoparticles (Gel/AgNPs) at low concentrations (1.25, 2.5, and 5 mM) were synthesized as radiation dosimeters. A high-energy ultrasonic homogenizer was used to dissolve the gelatin in distilled water and to disperse the AgNPs in the gelatin. The nanocomposites’ morphology and crystallinity were investigated using scanning electron microscopy (SEM), optical absorption, and Fourier transform infrared (FTIR) spectroscopies. Dose enhancement was assessed using X-ray irradiations with beam energies below and above silver K-edge. The beam was configured by setting the X-ray generator at 15, 25.5, and 35 kV potential and a beam current of 1 mA. An X-ray detector is used to detect the number of electrons after passing through Gel/AgNPs samples. The use of AgNPs embedded in gelatin caused the enhancement of X-ray radiation absorption, and the highest percentage of linearity for the dosimeter was found to be 90% in the optical range of 395 nm to 425 nm. The preliminary results demonstrated that Gel/AgNPs material may be used in radiation dosimetry for low-energy radiotherapy sources.

10

Spark plasma sintering of Al-SiC composites with high SiC content: study of microstructure and tribological properties

Leszczyńska-Madej Beata, Madej Marcin, Wąsik Anna, Garbiec Dariusz

Archives of Civil and Mechanical Engineering

|

2023

|

Vol. 23, no. 4

art. e229, 1--13

EN

The article presents the results of the microstructure and tribological properties of Al-xSiC composites (x =70 and 90 wt% SiC) produced in spark plasma sintering (SPS). Due to their attractive thermal, physical, and mechanical properties, aluminum matrix composites with high-volume fractions of silicon carbide (> 50%) have become a major area of interest as a potential material for multifunctional electronic packaging and cryogenic applications. The SPS process was carried out in a vacuum atmosphere under various conditions. Composites with a density close to theoretical (96-98%) were obtained. X-ray diffraction and scanning electron microscopy with EDS analysis were used to characterize the microstructure. Mechanical properties were determined by hardness measurements and a three-point bending test. The tribological properties of the composites were determined utilizing a block-on-ring tribotester. As a criterion for wear resistance, weight loss measured under specific friction conditions, that is, depending on the type of material and the applied load, was adopted. The researched materials were characterized by an even distribution of the carbide phase in the matrix. Composites with the highest SiC phase content (90 wt%) had higher hardness (2537 HV1) and flexural strength (242} 15 MPa) with worse wear resistance at the same time. The weight loss of this composite was 0.43 and 0.76% for friction under loads of 100 and 200 N, respectively, and was 360 and 270% higher than that determined for the composites with the lower content of the SiC phase (70 wt%). The wear rate was three times higher for the Al-90wt%SiC composites.

11

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

El-Mekawy Rasha E.

Polimery

|

2022

|

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.

12

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

|

2022

|

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.

13

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

Khan M. Naziruddin, Almohammedi Abdullah

Materials Science Poland

|

2022

|

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.

14

Effect of the Chemical Unhairing Process on Pulled Wool Characteristics

Abdellaoui Olfa, Harizi Taoufik, Msahli Slah

Fibres & Textiles in Eastern Europe

|

2022

|

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.

15

Biological and mechanical research of titanium implants covered with bactericidal coating

Malisz Klaudia, Świeczko-Żurek Beata

Engineering of Biomaterials

|

2022

|

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.

16

Compression behaviour of BFRP bars

Urbański Marek, Protchenko Kostiantyn

Archives of Civil Engineering

|

2022

|

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.

17

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

Staude Marek

Zeszyty Naukowe Akademii Morskiej w Szczecinie

|

2021

|

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.

18

Działanie czynników mechanicznych oraz termicznych na morfologię włosów ludzkich i zwierzęcych

Dobosz Magda, Kalska-Szostko Beata

Wiadomości Chemiczne

|

2021

|

[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.

19

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

|

2021

|

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.

20

Impaktor kaskadowy jako metoda poboru nanoobiektów do analizy mikroskopowej

Kozikowski Paweł, Sobiech Piotr, Oberbek Przemysław, Jakubiak Szymon

Podstawy i Metody Oceny Środowiska Pracy

|

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.