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PL
Produkcja odpadów medycznych na świecie jest bardzo duża, co przekłada się na zaśmiecenie środowiska. W ostatnim czasie produkcja odpadów medycznych została znacznie zwiększona z powodu przeciwdziałania wirusowi SARS-CoV-2, który wywołuje chorobę zwaną COVID-19 i przyczynił się do powstania pandemii. W celu zapobiegania zarażeniu się wirusem SARS-CoV-2 stało się powszechne używanie maseczek ochronnych, a tym samym na wysypiskach przybyło w ogromnym stopniu odpadów w postaci zużytych maseczek. Wychodząc naprzeciw ochronie środowiska zaproponowano metodę przetwarzania maseczek ochronnych, w sposób umożliwiający ich powtórne użycie do produkcji fibrobetonu. W artykule zaprezentowano wyniki badań wytrzymałości na ściskanie i na rozciąganie betonu zbrojonego włóknami pozyskanymi ze zużytych maseczek ochronnych składających się z warstw włókniny polipropylenowej. Wyniki badań betonu zbrojonego włóknami stanowiącymi 0,05% objętości mieszanki betonowej oraz 0,2% objętości mieszanki betonowej porównano z wynikami betonu referencyjnego.
EN
The production of medical waste in the world is very large, which translates into environmental pollution. Recently, the production of medical waste has been significantly increased due to the counteraction of the SARS-CoV-2 virus, which causes the disease called COVID-19 and contributed to the creation of the pandemic. In order to prevent infection with the SARS-Co-V-2 virus, it has become common to use protective masks, and thus a huge amount of waste in the form of used masks has arrived in landfills. To meet environmental protection, a method of processing protective masks was proposed in a way that allows their reuse for the production of fiber-reinforced concrete. The article presents the results of testing the compressive of concrete and the tensile strength of concrete reinforced with fibers obtained from used protective masks consisting of layers of polypropylene non-woven fabric. The test results of concrete reinforced with fibers constituting 0.05% of the concrete mix volume and 0,2% of the concrete mix volume were compared with the results of the reference concrete.
EN
Influence of the filler (alumina, copper, carbon fiber) and FDM printing parameters on PLA tensile strength was investigated. FDM process parameters (raster angle, layer thickness, number of coatings) were optimized using the ANOVA test. It was found that the most important parameter is the raster angle. Tensile strength increases as the raster angle increases and the number of shells as well as layer thickness (larger number of infills) decreases. The highest strength was achieved for PLA/PLA-Al2O3.
PL
Zbadano wpływ napełniacza (tlenek glinu, miedź, włókno węglowe) i parametrów druku FDM na wytrzymałość na rozciąganie PLA. Parametry procesu FDM (kąt rastra, grubość warstwy wewnętrznej, liczba warstw zewnętrznych) optymalizowano za pomocą testu ANOVA. Stwierdzono, że najbardziej istotnym parametrem jest kąt rastra. Wytrzymałość na rozciąganie wzrasta wraz ze wzrostem kąta rastra oraz zmniejszeniem liczby warstw zewnętrznych jak również grubości warstwy wewnętrznej (większa liczba wypełnień). Największą wytrzymałość uzyskano dla PLA/PLA-Al2O3.
PL
Artykuł przedstawia wyniki badań trzech fibrobetonów z dodatkiem włókien polimerowych. Wpływ rodzaju i ilości włókien był widoczny po zarysowaniu się belek. Na podstawie obliczonych wytrzymałości równoważnych, resztkowych, energii pękania oraz ilorazów odporności na pękanie stwierdzono, że fibrobeton z największą ilością makrowłókien osiągał najlepsze wyniki. Porównano trzecią i czwartą edycję Raportu Technicznego 34 oraz uznano, iż dodatek włókien umożliwia zwiększenie nośności płyty na gruncie obciążonej w środku oraz na krawędzi.
EN
The article presents the results of testing three polymer fiber reinforced concretes (FRC). The influence of fiber type and dosage became evident after cracking of beams. Based on the calculated equivalent and residual flexural tensile strengths, fracture energy, and toughness index, it was stated that FRC with the highest amount of macrofibers achieved the best results. The third and fourth editions of Technical Report 34 were compared and it was claimed that the fiber addition enables an increase in the load - carrying capacity of the ground slabs loaded at the centre and on the edge.
PL
W artykule oceniono, czy na podstawie wyników otrzymywanych z przenośnego twardościomierza Leeba można w dokładny sposób określić wytrzymałość na rozciąganie, która jest podstawowym parametrem pozwalającym na ustalenie gatunku stali. Wykonano pomiary próbek z dwóch różnych gatunków stali, dwóch różnych grubości oraz o dwóch różnych stopniach przygotowania testowanej powierzchni stali. Sprawdzono, czy kierunek wykonywania uderzenia wpływa na otrzymywane wyniki oraz jaka jest zależność pomiędzy twardością stali a stanem naprężeń w badanym elemencie. Otrzymane wyniki na podstawie twardości Leeba porównano z wartością wytrzymałości na rozciąganie uzyskaną z maszyny wytrzymałościowej. Wykazano, że na potrzeby praktyczne możliwe jest ustalenie wytrzymałości na rozciąganie stali na podstawie pomiarów wykonywanych przenośnym twardościomierzem Leeba, wykorzystującym metodę dynamiczną pomiarów.
EN
In this article, it was decided to check whether, based on the results obtained from a portable Leeb hardness tester, the value of tensile strength could be determined in an equally accurate way, so that it would be possible to determine the steel tensile strength. The measurements were performed for samples made of two different steel grades with different tensile strength, two different thicknesses and two different degrees of preparation of the tested steel surface. It was checked whether the direction of impact affects the results obtained and what is the relationship between the hardness of steel and the level of stress in the tested element. All obtained results based on Leeb hardness were compared with the tensile strength values obtained from the testing machine. It has been shown that for practical purposes it is possible to determine the steel tensile strength based on measurements performed with a portable Leeb hardness tester using the dynamic measurement method.
EN
Silk sericin protein is a natural high-molecular-weight compound that contains eighteen types of amino acids. It is non-toxic, biodegradable, and biocompatible, with simple preparation methods and low cost. It finds widespread application in functional clothing, medical and pharmaceutical fields, tissue engineering, and more. Nano-titanium dioxide, on the other hand, possesses non-toxic, self-cleaning, antibacterial, and deodorizing properties. To develop multifunctional textiles with deodorization, UV protection, and good thermal and mechanical properties, this study utilized a compounding method to modify citric acid-pretreated cotton fabrics through a two-dipping and two-padding process using a blend finishing solution of silk sericin protein and nano-titanium dioxide. Observations of the microstructure before and after fabric finishing, along with evaluations of deodorization, UV protection, and thermal properties, revealed that controlling the proportion of the silk sericin protein/nano-titanium dioxide blend finishing solution can result in a smooth surface of the modified cotton fabric. This modification not only enhances the fabric’s UV protection and tensile strength but also improves its thermal properties while imparting certain deodorization capabilities. Comprehensive analysis concludes that using silk sericin protein and nano-titanium dioxide for modifying cotton fabric to prepare multifunctional textiles with deodorization, UV protection, and good thermal and mechanical performance is feasibly viable.
EN
Friction stir processing (FSP) is a manufacturing technique that can be employed to produce aluminum 6082 surface composites (ASCs). These ASCs display considerable increases in hardness and tensile strength, which makes them ideal for a wide variety of automotive applications. One example is piston skirts that are used in the cylinder chamber. The primary emphasis of this research is to investigate the accumulative impact that several passes have on Al 6082 surface composites that were filled with graphite nanopowder. The mechanical properties and microstructure of the fabricated composites were studied in order to accomplish this goal. The microstructural investigation showed that the graphite nanopowder particles were evenly distributed throughout the Al-6082 alloy. In addition, better dispersion of the graphite nanopowder was seen throughout the matrix material as the number of passes made during friction stir processing was increased. This may be explained by the reduction in grain size that occurs inside the aluminum metal matrix composites (AMMCs) that are produced as a consequence. According to the results of the research, the microhardness of the material grew to 105.3 HV after the third pass of the tool, and its maximum tensile strength rose to 215±3 MPa. In the ASCs that fabricated after three passes of friction stir processing, the smallest grain size that was measured was 24 micrometers.
EN
One of the biggest challenges facing a designer of paper structures is its low resistance to moisture and water. Paper is a hydrophilic material that absorbs moisture from the outside. This causes the hydrogen bonds between the cellulose molecules to loosen and as a result a rapid decrease in strength parameters. In order to be able to use paper as a construction material, there is a need to select and evaluate the effectiveness of the appropriate impregnant, as well as to know its impact on the mechanical properties of the impregnated paper. The paper analyzes the effect of the use of various impregnations, including wood oil, yacht lacquer, and fire-retardant agent impregnation, on the tensile strength of several types of cellulose-derived materials, e.g. corrugated board, solid board, paper cores, and honeycomb board. The effectiveness of the impregnation was also assessed using the method of measuring the contact angle of the reference and impregnated surfaces.
EN
The subject of the article is the influence of filament moisture on the quality of products manufactured using the additive method using the Fused Deposition Modelling (FDM) method. Three types of thermoplastic polymers were tested: ABS, PLA and PET-G. The polymers were stored in environments with different humidity. The moisture content of the filament was determined as the water content in the material expressed as a percentage by weight. To obtain the expected humidity of the samples, they were conditioned for 7 days in tightly closed containers with constant humidity of 40%, 60% and 80%. After the sample conditioning process was completed, they were removed from the container and subjected to further tests. The influence of filament humidity on selected properties of manufactured products is presented, such as: surface quality of the obtained samples, tensile strength and dimensional repeatability. To sum up, the method of storing the filament affects the moisture content of the filament. The humidity of the filament, in turn, affects the quality of products manufactured using the FDM method, including: on: mechanical properties, dimensional stability, Surface appearance. Therefore, it is important in what conditions the filament is stored before the production process begins.
EN
Manufacturers always seek for quality and effective welding to stay competitive in the market. There is a continuous demand for a quick and efficient manufacturing set ups for new products. GMAW is among the welding processes that is wieldy used in the industry. Welding factors such as welding voltage, welding current, gas flow rate, filler wire size and welding speed play a significant role in determining the welding quality. Taguchi design uses optimization technique for the process of experimentation as an effort to improve productivity and enhance product quality. This study discusses the welding of commercial steel welded using GMAW. The welding was controlled by welding current, welding speed and groove shape to test their influence on the welding strength, tensile strength and hardness. X groove shape welding has obtained lower tensile strength and hardness than V groove shape as did higher welding current and lower welding speed. The results concluded that welding current welding had the highest influence on tensile strength and hardness of the welding, followed by groove shape, while the welding speed had the minimum influence. The optimized combination of welding factors is 170 A, V groove shape and 150 mm/min.
EN
Improvement of the mechanical properties of clayey soils by additional elements to enhance the strength under numerous freezing and thawing cycles has been considered as a serious concern for engineering applications in cold regions. The objective of the current study is to investigate the effect of nano-clay as a stabiliser on the mechanical properties of clay. To this end, the clay specimens were prepared by adding various percentages of nano-clay ranging from 0.5% to 3% by dry weight of soil and were experimentally tested under the uniaxial compression and tensile splitting tests under different curing times (0, 7 and 28 days) after experiencing various freeze–thaw cycles ranging from 0 to 11. It can be concluded from the results that nano-clay particles may be used as a stabiliser in geotechnical applications to improve soil property. The results indicate that the optimum moisture content (OMC) of specimens increases and the maximum dry density (MDD) decreases with the increasing nano-clay content. The specimens containing about 1% nano-clay recorded maximum values of unconfined compressive strength (UCS) as well as tensile strength. For example, the addition 1% nano-clay increased the UCS and tensile values of clay specimens under the curing time of 28 days by 34% and 247%, respectively. In addition, the long-term durability of specimens against freeze–thaw cycles increases further with the addition of nano-clay content ranging from 2% to 3%.
EN
The article details the principle behind Fused Deposition Modelling (FDM) technology. Strength tests were carried out on a Stratasys FORTUS 400mc industrial 3D printer. Prints of the strength specimens were made in different orientations in the working chamber of the machine.
PL
W artykule szczegółowo przedstawiono zasadę działania technologii FDM (Fused Deposition Modeling). Zostały przeprowadzone badania wytrzymałościowe na przemysłowej drukarce 3D Stratasys FORTUS 400mc. Wydruki próbek wytrzymałościowych zostały wykonane w różnej orientacji w komorze roboczej urządzenia.
PL
W artykule zaprezentowano wpływ pięciu rożnych redyspergowalnych proszków polimerowych (RPP) na wytrzymałość na rozciąganie (przyczepność w układzie wielowarstwowym) zapraw klejących do płytek ceramicznych (CTA), zawierających jako spoiwo wyłącznie cement wapniowo-siarczanoglinianowy (CSA). Wyniki badań wskazują, że dodatek RPP do zaprawy na bazie CSA powoduje wzrost wytrzymałości na rozciąganie oznaczanej jako przyczepność początkowa oraz po starzeniu termicznym. W przypadku wytrzymałości na rozciąganie próbek, badanych po zanurzeniu w wodzie, zaobserwowano różny wpływ w zależności od zastosowanego redyspergowalnego proszku polimerowego. Niezależnie od rodzaju RPP stwierdzono zmniejszenie wytrzymałości na rozciąganie próbek badanych po cyklach zamrażania i rozmrażania. Przeprowadzone badania wykazały, że istnieje możliwość opracowania zapraw klejących na bazie CSA, zawierających redyspergowalne proszki polimerowe, do stosowania wewnątrz pomieszczeń. Wyzwaniem badawczym, związanym z odpornością na zamrażanie, jest opracowanie CTA do zastosowania na zewnątrz obiektów.
EN
The purpose of this study was to investigate the effects of five different redispersible polymer powders (RDPs) on the tensile strength (adhesion in a multi-layer system) of ceramic tile adhesive mortars (CTAs) containing only calcium sulphoaluminate cement (CSA) as a binder. The results show that the addition of RDPs to CSA-based mortar results in an increase in tensile strength determined as initial adhesion and as adhesion after thermal aging. In the case of tensile strength tested after immersion of the samples in water, different effects were observed depending on the RDPs used. Regardless of the redispersible polymer powder used, a reduction in tensile strength was noticeable for samples tested after freeze-thaw cycles. The study showed that it is possible to develop a CSA-based ceramic tile adhesive using redispersible polymer powders for indoor use. The research challenge, related to freeze-thaw resistance, is to develop a CTA for outdoor applications.
13
Content available remote Badanie wytrzymałości na rozciąganie fibrobetonu z mikrozbrojeniem
PL
Celem pracy było określenie zależności pomiędzy wytrzymałością na rozciąganie betonu wysokowartościowego z mikrozbrojeniem, zbadaną w różny sposób: przez rozciąganie bezpośrednie, rozłupywanie i zginanie. W przypadku bezpośredniego rozciągania wykorzystano próbki o niepryzmatycznym kształcie oraz zaprojektowane akcesorium do maszyny wytrzymałościowej. Stwierdzono, że wytrzymałość w przypadku rozciągania bezpośredniego stanowi 0,23 ÷ 0,31 wytrzymałości na rozłupywanie i 0,21 ÷ 0,30 wytrzymałości na zginanie.
EN
The aim of the investigations was to determine relation between the tensile strength of the high performance concrete with microfibres, tested in various ways: by direct tension, splitting and bending. Direct tension was realized using the non-prismatic specimens and the designed accessory for the testing machine. It was found that strength by direct tension is 0.23 ÷ 0.31 of the splitting strength and 0.21 ÷ 0.30 of the flexural strength.
EN
Developing environmentally friendly and recyclable natural fiber-reinforced polymer composites has recently attracted researchers’ attention and interest. Herein, a comparative study was conducted to compare the mechanical properties of polypropylene (PP) composites with different natural fiber reinforcement, including palm fiber (Arenga pinnata), rice straw (Oryza sativa), coconut husk (Cocos mucifera), old world forked fern leaves (dicranopteris linearis), and snake plant (Sansevieria trifasciata). This study aimed to compare the influence of the five natural fiber materials on the tensile strength and flexural strength of PP composites. The natural fibers were chemically treated with a 5% NaOH solution for 2.5 hours. In the preparation of composites, polypropylene as the matrix is heated to 300 °C and mixed randomly with natural fibers. The test results indicate that the composite with the highest tensile strength (38% higher than the lowest) and flexural strength (102% higher than the lowest) is obtained using the PP composite with reinforced rice straw fiber. In contrast, the PP composites with palm fiber have the lowest tensile strength (72% from the highest tensile strength) and the lowest flexural strength (UFSmin) (62% from the highest flexural strength) corresponds to the PP composites with coconut fiber. This study revealed that the flexural strength of all composite samples was greater than that of pure PP.
PL
Przedstawiono i przedyskutowano wyniki badań popożarowej wytrzymałości konstrukcyjnej stali S355J2+N, niskowęglowej, o ferrytyczno-perlitycznej strukturze wewnętrznej. Wnioskowanie oparto na statycznej próbie rozciągania, prowadzonej na próbkach wystudzonych po ich uprzedniej ekspozycji na oddziaływanie temperatury pożarowej. Rozważono różny czas trwania incydentu pożarowego, różny poziom temperatury wygrzewania materiału i różny sposób jego studzenia. Oddziaływanie pożaru symulowano w scenariuszu badania izotermicznego.
EN
The results of post-fire strength tests performed for samples made of S355J2+N low-carbon structural steel, with ferritic-pearlitic microstructure, have been presented and widely discussed. The conclusion was based on the static tensile tests, carried out on samples cooled down after their prior exposure to fire temperature. Different duration of the fire incidents as well as various temperature levels of the material heating and also differentiated ways of its cooling down after the fire exposure were considered. The fire impact was simulated in an isothermal, steady-state heating regime.
EN
Concrete is a versatile and widely used construction material that has been in existence for centuries. Waste concrete comes from demolished concrete structures and has appeared as a worldwide challenge in recent years. Rather than disposing of waste concrete in landfills, it can be recycled and used for various purposes to protect natural resources and minimize environmental pollution. Managing waste has become important, because of an increase in the demand for natural resources as well as the amount of waste products produced during construction and demolition, both of which have exerted enormous pressure on the environment. Environmental studies that cover waste material recycling and reuse are becoming increasingly important today. Environmental pollution is thought to be best solved by using waste that was collected from demolished buildings, or natural resources, cleaned, and then reduced to aggregate form. Construction expenses are rising today, and the gradual influence on the environment has driven researchers to accept natural fibers, such as coconut fiber, for reinforcing concrete. Normal plain concrete cubes, cylinders, as well as coconut fiber cubes and cylinders were prepared. Coconut fibers are used at different ratios. A very small amount of admixtures called super-plasticizers is added to the concrete mix. As a result of their addition, the mixture becomes significantly more workable, and the water/cement ratio or even the amount of cement is lowered. Their performance is determined by the type of super-plasticizer SP used, the composition of the concrete mixture, the time of addition, and the temperature conditions at the time of mixing and concreting. The primary goal of the research study was to compare the characteristics of recycled concrete aggregate, RCA combined with natural Coconut fiber CF and SP Super plasticizer Chemrite-530 to those of Normal Plain Concrete under Compressive-Strength and Splitting-Tensile strength.
EN
Ethiopia has abundant invasive aquatic plants like water hyacinth and water lily. Large masses of these invasive plants have a negative impact on the country’s water bodies, specifically at Lake Tana in Ethiopia, by infesting and deteriorating water quality and reducing the quantity of water. In this research work, an attempt was made to fabricate a natural fiber reinforced composite in which water lily fiber was used as the reinforcing material in a polyester resin matrix. Chopped water lily fiber reinforced polyester resin composites were prepared by varying the fiber content - 20, 40 and 60 wt.%. Mechanical properties such as tensile strength and flexural strength were tested as per ASTM standards to evaluate the influence of the fiber contents. The experimental results show that an increase in the fiber content enhanced the mechanical properties of the water lily fiber reinforced polyester composite. It was found that the composite with 40 wt.% fiber exhibited superior strength which could be suitably used for different applications.
EN
Aluminium alloys have good mechanical and physical properties and are lightweight, easy to cast, and simple to machine. Aluminium alloys are widely used in the aviation industry, auto sector, defence sector, and structural industries because of their promising abilities. The fundamental aim of this study was to investigate the mechanical properties and physical characteristics of a stir cast hybrid aluminium nanocomposite reinforced with 1-3 wt.% cerium oxide (CeO2) and graphene nanoplatelets (GNPs). Utilizing SEM, microstructural analysis was carried out. The existence of the elements of the reinforcement in the manufactured nanocomposite specimens was verified using EDAX. With an increase in the reinforcement wt.%, improvements in the mechanical and physical properties were seen. In the hybrid nanocomposites reinforced with 3 wt.% GNPs and 3 wt.% CeO2, a low porosity of 1.06% was observed. The best results for tensile strength, yield strength, and microhardness were 398 MPa, 247 MPa, and 119.6 HV, respectively. The SEM micrographs of the studied materials showed that the reinforcement particles were uniformly dispersed and refined into ultrafine grains.
19
PL
Najnowsze badania wskazują na to, że nanomateriały mogą częściowo zastąpić cement w kompozytach cementowych. Ostatnio zaproponowanym zamiennikiem cementu w betonie są nanokompozyty tlenku grafenu. W związku z tym, w tym badaniu laboratoryjnym, zsyntetyzowano nanocząstki FeNi3/SiO2/GO [NFSG] oraz nanocząstki SiO2 [NS] i potwierdzono za pomocą analiz FTIR, SEM i TEM ich właściwości. Następnie zastąpiono nimi częściowo cement w ilości 1, 2 i 3% jego masy i określono ich wpływ na właściwości mechaniczne i trwałość próbek w wieku 7, 28 i 90 dni. Wyniki sugerują, że składy o najlepszych właściwościach mechanicznych przyniosły najlepsze rezultaty. W betonach tych wprowadzono 2% NFSG i 2% NS jako zamienniki cementu. Po 28 dniach beton zawierający NFSG zwiększył wytrzymałość na ściskanie o 15% i wytrzymałość na rozciąganie przy rozłupywaniu o 13%. Widma FTIR wykazały, że próbka zawierająca 2% NFSG wytworzyła więcej żelu C-S-H, poprawiając mikrostrukturę betonu, a tym samym jego właściwości.
EN
Recent research in the construction industry supports the idea that nanomaterials can partially replace cement. A recently suggested material as a suitable substitute for cement in concrete is graphene oxide nanocomposite. As a result, in this laboratory study, FeNi3/SiO2/GO nanoparticles [NFSG] and SiO2 nanoparticles [NS] partially replace cement by 1, 2, and 3% by mass after their synthesis and confirmation by FT-IR, SEM and TEM analyses and their impact on the mechanical and durability characteristics of the specimens at ages 7, 28, and 90 days were examined. The findings imply that the designs with the highest mechanical properties tests produced the best results. These designs used 2% of NFSG and 2% of NS substituting cement. After 28 days, NFSG-containing concrete increased compressive strength by 15% and splitting tensile strength by 13%. FTIR spectra demonstrated that specimen containing 2% of NFSG produced more C-S-H [calcium silicate hydrate] gel, improving the microstructure of concrete and subsequently its properties.
EN
Titanium and its alloys have significant uses in the biomedical, chemical, and aerospace industries. In this article, the current and gas flow rates were varied using Taguchi’s experiment design. The mechanical properties of the welded joint made using tungsten inert gas (TIG) welding and Ti6Al4V ELI as filler metal was characterized using the microstructure, microhardness, and tensile strength. The joint was classified into three regions, namely, fusion zone (FZ), heat affected zone (HAZ), and base metal (BM). Results show martensitic microstructure within the fusion zone (FZ) and the heat affected zone (HAZ), which resulted in an increased hardness within the fusion and heat affected zone.
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