Percentage Of Fibers Research Articles

Structural Behavior of Self-Compacting Bendable Mortar Beams reinforced by GFRP Bars under Monotonic Loads

Flexible or bendable concrete is an Engineered Cementitious Composite (ECC) that exhibits ductile material properties, in contrast to the brittle nature of conventional concrete. The material composition of conventional concrete is modified in order to impart a flexible nature to the material. This research presents the findings of an experimental study examining the flexural response of self-compacting bendable concrete beams reinforced by Glass Fiber Reinforced Polymers (GFRP) bars under a symmetrical two-point load. The experimental work comprised the casting of eight reinforced beams. The dimensions of all beams were identical: an overall height of 150 mm, a width of 100 mm, and a total length of 1,000 mm. The beams were classified into three groups based on the type of variables adopted and the type of the strengthening method employed, the percentage of steel fibers (1%, 1.5%, and 2%), and the percentage of Polyvinyl Alcohol (PVA) (0.2%, 0.3%, and 0.4%) were also considered. The following measurements were taken: the first cracking load, midspan vertical deflections, concrete surface strains, and the ultimate load capacity. Additionally, the crack patterns were recorded and the failure mode was observed, in addition to the mechanical properties of self-mortar bendable concrete (both fresh and hardened). The results indicated that an increase in the PVA ratio from 0.2% to 0.3% and 0.4% resulted in a notable rise in the modulus of rupture and modulus of elasticity, by approximately 16% and 40%, respectively, and 0.09% and 2%, respectively. The ductility of the beams increased with the steel fiber ratio due to enhanced flexural and splitting properties, which is a positive outcome. This allows for more caution to be exercised before the beam reaches its limit of stability. Furthermore, the value of deflection at maximum load increases with the increase of steel fiber content due to the increase in load capacity.

Influence of Bovine Myosin Heavy Chain Isoforms and Muscle Fiber Cross-Sectional Are<em>a o</em>n the Eating Quality and Connective Tissue Characteristics of 11 Different Beef Muscles

The objective of this study was to determine the impact of muscle fiber type, cross-sectional area (CSA), and diameter on the eating quality of 11 different beef muscles. Eleven different beef muscles were utilized in 2 separate studies. In the 2 studies, triceps brachii, rectus abdominus, rectus femoris, supraspinatus, gluteus medias, pectoralis profundi, semitendinosus, longissimus thoracis, longissimus lumborum, tensor fascia latae, and gastrocnemius were collected from 10 USDA Choice carcasses (N = 110). To determine muscle fiber type, myofibrillar proteins were extracted and separated via gel electrophoresis and immunoblot, while muscle fiber CSA and diameter were determined using a dystrophin antibody stain via fluorescence microscopy. Pearson correlation analysis was performed to determine the relationship between muscle fiber type, CSA, diameter, and the eating quality of the 11 beef cuts from previously reported studies. Muscles from both studies showed distinct differences in the relative percentage of type I and type IIA muscle fiber types, CSA, and diameter (P < 0.05). Correlation analysis from study 1 demonstrated positive correlations between type I fibers and many positive attributes of eating quality such as tenderness, juiciness, and lipid flavor intensity, while negative correlations were found between type IIA fibers and those attributes (P < 0.01). Interestingly, results from study 2 showed that increasing type I fiber percentage may also contribute to greater connective tissue content and collagen crosslink density (P < 0.01). Finally, a negative correlation was found between muscle fiber CSA and diameter with connective tissue amount (P < 0.05), and a positive correlation was found between muscle fiber CSA and diameter with tenderness measurements (P < 0.05) in both studies. Overall, muscles with greater type I fiber % delivered a more favorable eating experience than those with more glycolytic metabolism. Notably, increased CSA and fiber diameter did not diminish eating quality and were found to have a muscle-specific relationship with tenderness.

Muscle type-specific effects of bilateral abobotulinumtoxinA injection on muscle growth and contractile function in spastic mice.

Intramuscular injection of botulinum neurotoxin type A (BoNT-A) is commonly used to improve or maintain the joint range of motion in young children with spasticity. However, the effectiveness of BoNT-A treatment is variable and movement limitations are recurrent. Here we show long-term effects of a single, bilateral abobotulinumtoxinA (aboBoNT-A) injection in the gastrocnemius medialis and soleus muscles of wild-type and spastic (B6.Cg-Glrbspa/J with a mutation in the glycine receptor) mice at a young age (6-7 days). Specifically, we evaluated the impact of aboBoNT-A-A on gait, physical performance, and spontaneous physical behavior, as well as on contractile force characteristics, morphology, and histological phenotype of soleus and gastrocnemius muscles by comparing their results to those of saline-injected controls up to 9 weeks after the injection. The detailed time course of the study specifies the timing of the aboBoNT-A injection at 1 week, the period of behavioral studies from 4-9 weeks, and the age of the mice (10 weeks) at the time of contractile force characteristics and histology assessments. In spastic mice, aboBoNT-A injection had a minor and very specific effect on physical performance, by only modestly increasing stride length as a function of age. aboBoNT-A injection caused a reduction in the force-generating capacity and a slightly smaller physiological cross-sectional area in gastrocnemius medialis, but not in soleus. Reduced physiological cross-sectional area in aboBoNT-A-injected muscles was due to a lower number of muscle fibers, rather than reduced muscle fiber cross-sectional area. The percentage of slow-type muscle fibers and mitochondrial succinate dehydrogenase activity were increased, which was associated with an improved muscle endurance capacity. In conclusion, aboBoNT-A injection reduced the number of muscle fibers, causing muscle hypertrophy in remaining fibers and a shift towards more oxidative fibers, resulting in an improved endurance capacity and gait. This study proposed potential cellular mechanisms for the therapeutic efficacy of aboBoNT-A in spasticity.

Transcriptomic and Metabolomic Insights into Age-Related Changes in Lung Tissue of Yaks Under Highland Stress.

As an indigenous species on the Tibetan Plateau, the yak is well adapted to the plateau hypoxic environment. The high-altitude hypoxia adaptation of the yak requires the adaptive reshaping of multiple tissues and organs, especially the lungs. To reveal the adaptive development of yak lungs under hypoxic stress at the tissue and molecular levels, we conducted histomorphological observations as well as transcriptomic and metabolomic studies of yak lungs at three ages (0.5, 2.5, and 4.5 years). The results showed that the lung tissue developed significantly with age. The mean alveolar area was higher (p < 0.01) in 4.5 and 2.5-year-old yaks than in 0.5-year-old yaks. The percentage of elastic fibers, micro-arterial wall thickness, and micro-arterial area showed an increasing trend (p < 0.01) from 0.5-year-old yaks to 2.5-year-old yaks and then to 4.5-year-old yaks. In addition, some critical differentially expressed genes related to angiogenesis (MYC, EPHA2, TNF), fiber formation (EREG), smooth muscle proliferation (HBEGF), erythropoiesis (SOCS3), and hypoxia response (ZFP36) were identified. Some metabolites associated with these genes were also found simultaneously. These findings provide a deeper understanding of the molecular strategies underlying this species' extraordinary ability to survive normally in low-oxygen environments. In conclusion, the lungs of yaks undergo continuous adaptive development under hypoxic stress, and these findings are crucial for understanding the molecular mechanisms by which native species of the Tibetan Plateau survive in harsh environments.

Experimental and numerical evaluation of fibre-reinforced concrete vault forming slabs subjected to low-velocity impact loading

Vaults and dome structures are attractive in architecture due to their ability to evenly distribute weight and support substantial loads without internal columns. Fibre-reinforced concrete is ideal for these compressive structures, which experience low tensile stress. Assessing their performance under impact loading is crucial for safety, financial protection, and preserving cultural heritage. In this study, twelve arch-shaped slabs with thicknesses of 50, 75, and 100 mm, incorporating varying fibre percentages, were tested using a drop-weight impact test machine. Finite element analysis, validated against experimental results, was employed to evaluate the slabs’ behaviour under low-velocity impacts. The analysis revealed multiple flexural cracks in fibre-reinforced specimens, with maximum crack widths decreasing as fibre ratios increased. Although the number of microcracks rose with higher fibre content, crack spacing diminished. Results indicated that adding steel fibres significantly enhances tensile strength and energy absorption—showing a 90% increase in the 100 mm thick dome with 1.5% fibres—while reducing cracking. These improvements contribute to the durability, stability, and safety of concrete domes, lowering maintenance costs. Thus, incorporating steel fibres in the design and construction of impact-resistant concrete domes is highly recommended.

Properties of polyurethane foam/natural fibre composite for air conditioning insulation

ABSTRACT This study focuses on the fabrication of a biocomposite with insulating properties suitable for application in refrigeration pipe systems. The objective of this study was to utilise coconut husk and rice husk in a 1:1 ratio as reinforcement for flexible polyurethane foam. Biocomposites were made using hand mixing and casting technique reinforcement ratios of 5%, 10%, 15%, 20%, and 25% weight ratios from reinforcement husks. A thermal resistivity test, along with tensile test and water absorption measurements as a function of fibre content, was conducted according to ASTM standards. The study demonstrated that incorporating coconut and rice husks as reinforcement in polyurethane foam significantly improved the tensile properties of the composite material. The composite reinforced with 25% weight has been found to have highest tensile stress. In contrast, the thermal resistivity is observed to decrease as the fibre content is increased. A maximum thermal resistivity at 5% wt was found from the reinforcement. On the other hand, the amount of water absorption of the polymer compound increases with the increase in weight percentage of natural fibres. Based on these results, Flexible polyurethane foam reinforced with coconut husks and rice husks shows a promising solution for use as insulation for air conditioning pipes.

Evaluating mechanical performance of coconut fibre reinforced polymer composites with variable fibre content

The rapid growth of composite materials, leveraging natural ingredients such as dried fruit, rice husk, wheat husk, straw, and hemp fibres, has expanded their applications and market presence. Among these, coconut fibre stands out due to its high tensile strength, making it a promising reinforcement for polymer composites. However, increasing the coconut fibre content can reduce the cohesion and some properties of the composites. This study investigates the impact of the weight percentage of coconut fibres on the mechanical properties of coconut fibre-reinforced composites. Various composites were prepared with different weight percentages of coconut fibre, and their mechanical properties were evaluated using tensile tests with a Universal Testing Machine Instron 8872 and hardness tests with a Digital Shore Scale “D” Durometer. The results indicate significant changes in tensile strength, tensile strain, and hardness corresponding to the weight percentage of coconut fibre. This research highlights the importance of optimizing fibre content to achieve balanced mechanical properties in coconut fibre-reinforced composites.

Study of mechanical properties of composite materials reinforced with aluminum fibers

This study investigates the mechanical properties of composite materials reinforced with aluminum fibers of varying lengths and concentrations. The research aims to evaluate the effects of fiber reinforcement on both flexural and compressive strengths, using fibers of three distinct lengths (2×20 mm, 2×30 mm, and 2×40 mm) and four different concentrations (0.5%, 1%, 1.5%, and 2%) by weight within the composite matrix. Mechanical tests were performed after 28 and 56 days of curing to assess the influence of fiber reinforcement over time. The results demonstrate that increasing fiber length and concentration generally improves the flexural and compressive strengths, with the most notable gains observed at moderate fiber content. However, the study also finds that excessively high fiber percentages may lead to diminishing returns in strength performance, possibly due to fiber agglomeration or stress concentration effects. These findings provide valuable insights into optimizing the design of fiber-reinforced composite materials for various structural applications, enhancing both performance and material efficiency.

Влияние на две системи на земеделие върху продуктивността и биохимичните качества на лимец и ръж

The experiment was conducted in the period 2019 - 2022 in the experimental field of the Institute of Agriculture in Karnobat. The aim of the research was to determine the influence of two farming systems - organic and conventional on the productivity and biochemical characteristics of rye (Secale cereale L.) and triticale (Triticum monococcum L.). The crop structure and grain yield of rye and einkorn grown in different farming systems depend not only on the studied factor, but also on weather conditions during the growing season of the crops. Organic farming of both crops promotes the formation of higher number of spike-bearing stems compared to conventional farming. We believe that this is a compensatory mechanism, especially under unfavorable climatic conditions. In the case of organically grown rye and einkorn, the plant height, spike length, number of grains in the spike, mass of the grain in the spike were lower than the conventional ones. For organically grown einkorn, despite differences in agro-meteorological conditions, spike length remained stable over the years, but was 18% shorter than that of conventional. The biochemical parameters of the crops differ according to the cultivation method, with conventional rye having a higher percentage of crude protein and lower ash values compared to organic. The lysine content is almost the same in both cultivation methods, but the percentage of crude fiber is higher in conventional farming. Despite lower crude protein levels, organically grown einkorn showed greater stability in ash and fiber content over the years, as well as higher lysine content.

Suppression of Aseptic Inflammation Reduces the Severity of Remodeling of the Pulmonary Artery Branches and Improves Progressing of Experimental Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a complication of pulmonary embolism, characterized by increased pressure in the pulmonary artery and impaired lysis of thromboemboli. Previously, the presence of aseptic inflammation in CTEPH was identified in the wall of the pulmonary artery branches and perivascularly. However, the role of this inflammation in the CTEPH formation is unknown. The aim of the work was to study the effect of aseptic inflammation on the CTEPH formation and progression. The experiments were performed on 54 male rats. The CTEPH model was reproduced by repeated intravenous administration of partially biodegradable microspheres (MS). Immediately after the last administration of MS, all animals were divided into groups: control CTEPH (c.CTEPH) – saline solution was administered intramuscularly (i/m) for 6 weeks; low dose of prednisolone (LD) – prednisolone was administered i/m at a dose of 1.5 mg/kg; high dose (HD) – prednisolone was administered i/m at a dose of 6 mg/kg; healthy animals. After 6 weeks, the following was performed: treadmill test, TTE, cardiac catheterization with manometry, and histological examination of the lungs. In a separate series of experiments, the severity of inflammatory infiltration of the vascular wall and perivascular zone was assessed by immunohistochemical studies (IHC). In the LD group, there was the decreasing of hypertrophy index (HI) and the percentage of collagen fibers in the vascular wall compared to c.CTEPH. There was a significantly greater reduction in HI compared to HD. In the HD group, there was positive effect on the percentage of collagen fibers in the vascular wall, this parameter did not significantly differ from healthy animals. According to IHC data, prednisolone in low dose effectively suppressed inflammatory infiltration of the vascular wall and perivascular space. The results of the study revealed the ability of prednisolone, by suppressing aseptic inflammation, to reduce the severity of remodeling of the pulmonary artery branches.

Sodium danshensu modulates skeletal muscle fiber type formation and metabolism by inhibiting pyruvate kinase M1.

Sodium Danshensu (SDSS) is extracted from Salvia miltiorrhiza and has many pharmacological effects. However, little is known about its effects on muscle fiber formation and metabolism. Here, we aimed to investigated the role and molecular mechanisms of SDSS in modulating the formation of skeletal muscle fiber. C2C12 cells were incubated in differentiation medium with or without SDSS for 4days. C57BL/6 mice were orally administered SDSS by gavage once a day for 8weeks. Grip strength, treadmill, muscle weight, western blotting, qPCR, immunofluorescence staining and H&E staining were performed. SDSS target proteins were searched through drug affinity responsive target stability (DARTS) and mass spectrometry analysis. Furthermore, molecular docking was carried out for Pyruvate kinase M1 (PKM1). The effect of PKM1 on myosin heavy chain (MyHCs) gene expression was verified by knockdown of PKM1 experiment. SDSS induced oxidative muscle fiber-related gene expression, and inhibited glycolytic fiber-related gene expression in C2C12 cells. Muscle mass, the percentage of slow oxidative fibers, succinic dehydrogenase activity, muscle endurance, glucose tolerance, and the expression of the MyHC1 and MyHC2a genes increased while MyHC2b expression, lactate dehydrogenase activity, and the percentage of glycolytic muscle fibers decreased in SDSS-treated mice. Mechanistically, SDSS bound to the pyruvate kinase PKM1 and significantly repressed its activity. PKM1 inhibited MyHC1 and MyHC2a expression but promoted MyHC2b expression. SDSS also significantly attenuated the effects of PKM1 on muscle fiber-related gene expression in C2C12 cells. Our findings indicate that SDSS promotes muscle fiber transformation from the glycolytic type to the oxidative type by inhibiting PKM1 activity, which provide a new idea for treating muscle atrophy, muscle metabolism diseases and improving animal meat production.

Phytochemical profiling from Dioscorea bulbifera L. bulbils using LC-MS, proximate analysis and antidiabetic activity: in vitro and in silico approaches

ABSTRACT The nutritional value and medicinal properties of highly edible Bulbils of Dioscorea bulbifera L are still unexplored. This study reported the nutritional and medicinal values by In vitro, and In silico studies along with chemical profiling using LC-MS. The proximate analysis was conducted by the AOAC method. The antioxidant and antidiabetic activities were assessed using DPPH and α- α-glucosidase enzyme inhibition assay. Molecular docking was used to do an In silico examination of the identified molecules, and ADMET analysis of the hit candidate was also performed. The result showed that bulbils of D. bulbifera were found to have a higher percentage of protein (8.83%), fat (0.96%), and fiber (5.40%). It exhibited significant levels of phenolic and flavonoid content 106.93 ± 0.02 mg GAE/g and 11.51 ± 0.02 mg QE/g, respectively. The ethyl acetate fraction of D. bulbifera showed potent antioxidants with an IC 50 = 13.75 ± 0.6 μg/mL. Furthermore, the methanol extract showed more than 50 % inhibition activity with IC 50 values of 26.29 ± 0.6 μg/mL and 191.2 ± 0.7 μg/mL against α-glucosidase and α-amylase, respectively. The ethyl acetate fraction showed higher α-glucosidase and α-amylase inhibitory activity with an IC 50 of 14.42 ± 0.4 μg/mL and 171.5 ± 0.4 μg/mL, respectively, compared to the standard acarbose (p < 0.05). Chemical profiling of most bio-active ethyl acetate fraction was done using LC-MS analysis, where eleven compounds were annotated. In conclusion, bulbils of D. bulbifera demonstrate promising anti-diabetic activity through In vitro and In silico studies.

Effect of extrusion on physicochemical and functional properties of cladode flour from Opuntia cochenillifera and Opuntia ficus-indica

In this study, the physicochemical and functional properties of flours obtained from mature cladodes of two nopal species, Opuntia cochenillifera (OC) and Opuntia ficus indica (OF), subjected to different extrusion conditions, varying moisture (20 % and 26 %) and temperature levels (120 °C, 140 °C and 160 °C) were evaluated. The results showed significant differences in chemical composition, physical, functional and phytochemical properties between the two species. OC had a higher ash and ether extract content (29.27 % and 1.28 % respectively), while OF had more protein and carbohydrates (7.83 and 55.31 % respectively). The expansion index was higher (1.06 – 1.27) in OF, especially under high temperature extrusion and low moisture conditions. Bulk density decreased with increasing extrusion temperature, and color was significantly altered by temperature and moisture, with greater changes observed in OF. Functional properties such as oil absorption capacity, water absorption capacity, and water solubility index, were significantly affected by the extrusion process in both species of nopal. In terms of dietary fiber, extrusion increased (4.99 to 10.38 %) the soluble fiber content and decreased (36.91 to 32.30 %) the insoluble fiber content in both species. However, OC had a higher percentage of soluble and total dietary fiber. Phenolic compounds, flavonoids and antioxidant activity were significantly affected by the extrusion process in most treatments, although some maintained or improved these properties. These results highlight the influence of species and extrusion conditions on the properties of nopal flours, providing valuable information for the development of nopal-enriched food products, thereby optimizing their nutritional and technological properties.

Pork quality and histological properties of longissimus muscle from boars and early and late immunocastrated pigs

Immunocastration has been introduced in pig production to reduce boar taint. However, there is not much information on how different schedule of immunocastration affects meat quality, especially muscle histological properties. In this study, carcass and meat quality characteristics, histological properties of the longissimus dorsi muscle, sensory characteristics and fatty acid composition of meat and fat from entire males (EM), late immunocastrated (LIC, first dose 8 weeks before slaughter, second dose 4 weeks before slaughter) and early immunocastrated pigs (EIC, first dose 13 weeks before slaughter, second dose 8 weeks before slaughter) were compared. Fat thickness was greater in EIC than in LIC and EM. Meat quality parameters differed mainly between EIC and EM, as EIC had a higher pH 45, lower electrical conductivity, lighter and more yellowish loins and lower drip loss than EM. EM had a higher protein and moisture content and a lower fat content than EIC and LIC. No major effect on histological properties was observed, however, the percentage of fast-twitch oxidative fibres tended to be lower in both LIC and EIC animals compared to EM. Pork from EM had higher boar taint and lower pork odour and flavour scores and higher pig and boar taint flavour scores. The results of this study show that the immunocastration schedule influences some carcass, meat and fat quality traits and, because of that, it can be modified to obtain the desired final product.

Sifat Mekanik Komposit Serat Eceng Gondok dengan Filler Cu-Zn dan MgO untuk Kampas Rem Sepeda Motor

Brake linings are an important component in the vehicle braking system, but the use of hazardous materials such as asbestos causes environmental pollution. This research aims to analyze the effect of water hyacinth fiber content in composites with Cu-Zn and MgO fillers on brake lining wear and hardness, as a more environmentally friendly alternative. The experimental method was used with variations in the composition of water hyacinth fiber: brass powder: magnesium oxide powder: epoxy resin of 10%:40%:20%:30%, 15%:40%:20%:25%, 20%:40%: 20%:20%, and 25%:40%:20%:15%. The manufacturing process involves a compaction pressure of 2 tons for 10 minutes and sintering at a temperature of 200°C for 30 minutes. Vickers hardness testing refers to the ASTM E384 standard and wear testing refers to the ASTM G99-95a standard. The results showed that the highest hardness was obtained with a composition of 10% water hyacinth fiber (245.26 Kgf/mm2), with a composition of 15% water hyacinth fiber (240.88 Kgf/mm2), with a composition of 20% water hyacinth fiber (215.84 Kgf /mm2), and a water hyacinth fiber composition of 25% (194.48 Kgf/mm2). The lowest wear test results were at a composition of 10% water hyacinth fiber (0.00212 mm²/kg), at a composition of 15% water hyacinth fiber (0.00242 mm²/kg), at a composition of 20% water hyacinth fiber (0.00295 mm²/kg), and with a composition of 25% water hyacinth fiber (0.0031 mm²/kg). This shows that increasing the percentage of water hyacinth fiber can reduce the hardness value and increase brake lining wear.

Thermo-mechanical behavior of compressed earth blocks (CEB) stabilized and reinforced with fibers

This study is part of the development of eco-materials (dune sand, clay soil and natural fibers) for masonry and the rehabilitation of heritage in arid and semi-arid environments which are found in abundance in North Africa. The manufacture of compressed earth bricks stabilized (BTCS) has gained some momentum over the last decade. First, we present the results of characterization tests of sand-clay mixtures based on the compressive strength criterion. Secondly, an optimization of the stabilizer of the sand-clay mixtures using different percentages of lime was carried out. The choice of lime as a stabilizer remains an environmental reason. In the last step, the optimal mixture obtained (sand-clay-lime) based on the compressive strength criterion will be reinforced with different percentages of natural fibers of different lengths. The formulation of the mixture (sand-clay-lime-fibers) optimally meets the regulatory requirements (mechanical and thermal) of arid and semi-arid zones known as very hot in summer and cold in winter. Finally, the results obtained open up a field of contribution to the manufacture of a local ecological eco-material at low cost.

Characterization of bauxite residue filled sisal/glass fiber reinforced hybrid composites for structural applications

Abstract Composite materials with high compressive, flexural, and shear strength are essential for constructing various structural elements in automotive, aerospace, marine, and construction sectors. The present research aims to create bauxite residue filled sisal/glass fiber reinforced polyester composites. The different weight percentages of sisal fiber (35 %, 30 %, 25 %, and 20 %), red mud (0 %, 5 %, 10 %, and 15 %), glass fiber (5 %), and polyester matrix (60 %) were used to fabricate composites. The combined use of compression molding and hand layup technique was employed in the creation of composite materials due to its frequent utilization in the manufacturing of large-scale components found in various sectors, including automotive, aerospace, marine, and construction. In this work, investigated the physical, compressive, flexural and v notch rail shear strength of the fabricated composites. Results revealed that the composites with 30 % of sisal fiber and 5 % of red mud has the highest compressive, flexural, and v notch rail shear strength of 83.45 MPa, 182.74 MPa, and 10 MPa, respectively. Further, this composite showed high density, less void content, and less thickness swelling than other composites. According to the outcomes, this composite material demonstrates suitability for various structural applications across automotive, aerospace, marine, and construction sectors.

Development of Fiber-Reinforced Polymer Composites for Additive Manufacturing and Multi-Material Structures in Sustainable Applications

This study investigates the mechanical properties of carbon and natural fiber-reinforced Polylactic Acid (PLA) and Polyethylene Terephthalate Glycol (PETG) composites produced via Additive Manufacturing (AM), focusing on Material Extrusion (MEX). The performance of filaments made from pre-consumer recycled PLA (rPLA) and PETG, with varying weight percentages of hemp and jute short fibers, was evaluated through tensile testing. Comparisons were made between the original filaments (PLA, carbon fiber-reinforced PLA [CF–PLA], and PETG) and their recycled versions. Multi-material compositions—neat PLA and PETG, single-graded (PLA + CF–PLA, PETG + CF–PETG), and multi-gradient (PLA + CF–PLA + PLA, PETG + CF–PETG + PETG)—were analyzed for mechanical properties. Optical microscope images of multi-material specimens were captured before and after fracture to assess failure mechanisms. The results indicate that the original CF–PETG filaments achieved a tensile strength of 50.14 MPa, which is higher than rPLA, PLA, and CF–PLA by 2%, 70%, and 6.7%, respectively. The re-manufactured PLA filaments reinforced with 7 wt% hemp fibers exhibited a tensile strength of 38.8 MPa, representing a 29% increase compared to the original PLA filaments and a 26% improvement over recycled PLA. Additionally, incorporating 7% jute fiber into PETG resulted in a tensile strength of 62.38 MPa, reflecting a 12% improvement over the original PETG filaments and a 15% increase compared to the recycled PETG filaments. Among specimens produced by AM, CF–PLA and rPLA demonstrated the highest tensile and compressive strengths. However, multi-material composites showed reduced mechanical performance compared to neat PLA and PETG, highlighting the need for improved interlayer adhesion. This study emphasizes the importance of optimizing material combinations and fiber reinforcement to enhance the mechanical properties of composites produced through AM.

EXPERIMENTAL APPROACH FOR DEVELOPMENT OF SUSTAINABLE HYBRID GRADED FIBER REINFORCED CONCRETE BY CONSUMING LATHE WASTE STEEL FIBERS WITH GLASS FIBERS FOR ENHANCED MECHANICAL PROPERTIES

Local workshops generate large quantities of industrial lathe waste steel fibers, which the steel manufacturing industries find difficult to recycle because of their sharp edges. The utilization of lathe waste steel fibers as fiber reinforcement is sustainable in concrete because these fibers have the same properties as steel fibers. Furthermore, using combinations of ductile and elastic fibers improves strain capacity and resistance to pre- and post-cracking. This research employs hybrid fiber reinforcement technology, utilizing industrial lathe waste steel fibers and glass fibers in varying proportions, to bridge the micro and macro cracks in concrete specimens. This research was done to examine the physical (workability) and mechanical properties (compressive and flexural strength) of hybrid fiber-reinforced concrete. In this research different mixtures of hybrid fiber-reinforced concrete were cast and designated as M0, M1, M2, M3, M4, M5, and M6. The mixtures included lathe waste steel fibers at 0%, 0.50%, 1%, 1.5%, 2%, 2.5%, and 3%, and glass fibers at 0%, 0.15%, 0.25%, 0.45%, 0.60%, 0.75%, and 0.90%, respectively. The ASTM-standardised protocols were followed for all laboratory testing. The physical property results showed a decrease in the workability of concrete mixes as the percentage of lathe waste steel and glass fiber increased. This suggests that a higher percentage of lathe waste steel and glass fibers leads to a lower slump value. Consequently, the mechanical property results showed a gradual enhancement in the compressive and flexural strengths of hybrid fiber-reinforced concrete up to 2.5% lathe waste steel fibers and 0.75% (M5). Further incorporation causes a reduction in strength. The physical examination of fractured samples of hybrid fiber-reinforced concrete confirms that the lathe waste steel fibers yield a maximum strain before breaking down in the concrete matrix. Furthermore, lathe waste steel fibers broke rather than being pulled out, indicating a good bond with the concrete. It is recommended that up to 2.5% lathe waste steel fibers and 0.75% of glass fibers by the total weight of the concrete can be used as hybrid fiber reinforcement for optimum strength achievement.

Facile fabrication of 3D-printed cellulosic fiber/polylactic acid composites as low-cost and sustainable acoustic panels

This work presents a green, cost-effective and eco-friendly strategy to reduce noise pollution by developing biopolymer-based 3D-printed acoustic panels. We successfully fabricated two series of composites by varying the weight percentage (wt%) of cellulose fibers of water hyacinth (WH) and pineapple leaf (PAL), with polylactic acid (PLA) as the matrix via the heat-press method. All samples were characterized using Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). Physico-mechanical properties, including hardness, tensile, and impact strength, were improved with increasing fiber loading. Filaments of 1 wt% water hyacinth fibers (WHFs) in PLA (1 WHF/PLA) and 1 wt% pineapple leaf fibers (PALFs) in PLA (1 PALF/PLA) were prepared and tested for 3D printability. The sound absorption coefficients (α) of the 3D-printed panels were investigated from 500 to 5000 Hz sound frequency range. The 3D-printed 1 WHF/PLA and 1 PALF/PLA acoustic panels achieve a maximum α (α-max) of 0.55 and 0.83 at 5000 and 4000 Hz, respectively, featuring the first work to report α-max > 0.5 at low fiber loadings in the high-frequency sound range. The tensile strength of the 3D-printed versions is significantly higher than non-3D-printed counterparts and commercial acoustic absorbers. Our data suggest the prepared 3D-printed panels are excellent candidates for acoustic applications at high-frequency noises. This study exhibits a facile, environmentally benign and sustainable approach to construct highly efficient and mechanically robust biopolymer-based 3D-printed sound-proof panels, which have promising potential as green engineering materials. Interestingly, this research also proposes a mitigation technology for the freshwater invader, Eichhornia crassipes (water hyacinths).