Maximum Mechanical Strength Research Articles

Development of an in-situ forming collagen-based hydrogel as a regenerative bioadhesive for corneal perforations

Corneal injuries play a significant role in global visual impairment, underscoring the demand for innovative biomaterials with specific attributes such as adhesion, cohesion, and regenerative potential. In this study, we have developed a biocompatible bioadhesive for corneal reconstruction. Derived from Collagen type I, naturally present in human corneal stromal tissue, the bioadhesive was cross-linked with modified polyethylene glycol diacrylate (PEGDA-DOPA), rendering it curable through visible light exposure and exhibiting superior adhesion to biological tissues even in wet conditions. The physicochemical characteristics of the proposed bioadhesive were customized by manipulating the concentration of its precursor polymers and adjusting the duration of photocrosslinking. To identify the optimal sample with maximum adhesion, mechanical strength, and biocompatibility, characterization tests were conducted. The optimal specimen, consisting of 30 % (w/v) PEGDA-DOPA and cured with visible light for 5 min, exhibited commendable adhesive strength of 783.6 kPa and shear strength of 53.7 kPa, surpassing that of commercialized eye adhesives.Additionally, biocompatibility test results indicated a notably high survival rate (>100 %) of keratocytes seeded on the hydrogel adhesive after 7 days of incubation. Consequently, this designed bioadhesive, characterized by high adhesion strength, robust mechanical strength, and excellent biocompatibility, is anticipated to enhance the spontaneous repair process of damaged corneal stromal tissue.

Structure, Property Optimization, and Adsorption Properties of N,N'-methylenebisacrylamide Cross-Linked Polyacrylic Acid Hydrogels under Different Curing Conditions.

In this study, polyacrylic acid hydrogels were prepared by modulating the cross-linking agent mass ratio using UV and heat curing methods. The structures and properties of the hydrogels were characterized and analyzed using Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis. The results showed that the mechanical properties of the hydrogels prepared through UV curing were better than those prepared through heat curing. The maximum mechanical tensile strength of 139 kPa was achieved at a cross-linking agent mass ratio of 3.85% with 20 min of UV curing, and the maximum mechanical compressive strength of 0.16 MPa was achieved at a cross-linking agent mass ratio of 2.91% with 20 min of UV curing. However, the hydrogels prepared by heat curing had a higher tensile strength than those prepared using the heat curing method. In addition, the thermally cured hydrogels had higher water absorption and adsorption properties. Moreover, the PAA hydrogels prepared at cross-linking agent mass ratios of 1.91 and 2.91% with 2 h of the heat curing method had the best swelling properties. Moreover, the increase in the cross-linker mass concentration led to a decrease in the pore size and porosity and to a more compact structure.

Engineering Tough and Elastic Polyvinyl Alcohol‐Based Hydrogel with Antimicrobial Properties

Hydrogels have been extensively used for tissue engineering applications due to their versatility in structure and physical properties, which can mimic native tissues. Although significant progress has been made toward designing hydrogels for soft tissue repair, engineering hydrogels that resemble load‐bearing tissues is still considered a great challenge due to their specific mechanophysical demands. Herein, microporous, tough, yet highly compressible poly(vinyl alcohol) (PVA)‐based hydrogels are reported for potential applications in repairing or replacing different load‐bearing tissues. The synergy of freeze‐thawing and the Hofmeister effect, which controlled the spatial arrangement and aggregation of polymer chains, facilitated the formation of microstructured frameworks with tunable porosity. While the maximum mechanical strength, toughness, and stretchability of the engineered hydrogel were ≈390 kPa, ≈388 kJ m−3, and ≈170%, respectively, Young's modulus based on compression testing wasfound to be in the range of ≈0.02–0.30 MPa, highlighting the all‐in‐one mechanically enriched nature of the hydrogel. Furthermore, the minimal swelling and degradation rate of the engineered hydrogel met the specific requirements for load‐bearing tissues. Finally, excellent antibacterial resistance as well as in vitro biocompatibility of the hydrogel demonstrates its potential for the replacement of load‐bearing tissues.

Study on design strategies and on new structure-performance relationships for CO2 capture in gas-liquid hollow fiber membrane contactors

The urgent need for carbon dioxide (CO2) capture technologies motivates this chemical engineering study, which systematically investigates the influence of macroscopic and microscopic structure on the CO2 absorption performance of hydrophobic alumina (Al2O3) hollow fiber membrane (A-HFMs) contactors. Six different A-HFMs prepared using the non-solvent-induced phase separation (NIPS) method with select solvents followed by sintering at 1300°C were then tested for chemical CO2 absorption in an A-HFM contactor using a monoethanolamine (MEA) solution. The hydrophobicity of the coatings applied on the A-HFM surfaces was confirmed by the water contact angle and thermogravimetric (TGA) analysis. Pearson's statistical analysis of a correlation matrix revealed the strength of relationships between nine variables, including outer diameter (mm), inner diameter (mm), percentage of sponge layer (%), pore size (nm), maximum pore size (nm), mechanical strength (MPa), surface porosity (m−1), overall porosity (%), and CO2 absorption flux (mol m−2 s−1). Building upon these findings, this study unveils a novel non-linear function linking three specific microscopic characteristics— pore size, surface porosity, and a geometric sponge layer factor—to CO2 absorption flux, offering valuable insights for optimizing hydrophobic A-HFM design and enhancing CO2 capture efficiency. The A-HFM, characterized by the combination of three factors (higher pore size, increased surface porosity, and a thicker sponge layer), achieved a CO2 absorption flux of 6.36 ×10−3 mol m−2 s−1 at room temperature, showcasing its exceptional performance in capturing CO2. The resulting empirical morphological factor provides a novel approach for enhancing the performance of CO2 absorption through A-HFM design optimization.

Mechanical strength distribution in Geminid meteoroids derived via fireball modeling

Context. Geminids are the most active annual meteor shower observed on Earth. Their parent is an active asteroid, (3200) Phaethon, which is a target of the planned DESTINY+ mission of the Japan Aerospace Exploration Agency (JAXA). The exact physical nature of (3200) Phaethon and Geminids is still debated. Aims. This paper is devoted to fragmentation modeling of bright Geminid fireballs, which should reveal information about the structure of centimeter-sized Geminid meteoroids. These fireballs were observed by the European Fireball Network (EN) over the past few years. We aim to describe their disintegration cascade in the atmosphere and their mechanical properties, and to derive their precise initial masses and velocities. Methods. We used a semi-empirical fragmentation model that employs an automatic procedure based on parallel genetic algorithms to determine the aerodynamic pressures at which a meteoroid and its parts fragment. This serves as a proxy for the mechanical strength of the body and its subsequent fragments. It enabled us to derive the minimum, median, and maximum mechanical strength and the strength distribution inside the meteoroid and reveal its internal structure. Results. We find that the Geminids begin to crumble at pressures 1–100 kPa, with the strongest parts reaching pressures of between 0.4 and 1.55 MPa before fragmenting. Knowing the spectral type of (3200) Phaethon (a B-type asteroid, part of the C complex), we conclude that the Geminids are made of compact and coherent carbonaceous material. We also find that the minimum aerodynamic pressure that causes the fragmentation of Geminids increases with increasing entry mass of Geminids. In contrast, the median aerodynamic pressure decreases as their entry mass increases. The spectra of all the observed Geminid fireballs show normal content and little variation in terms of sodium.

Polymer electrolyte membrane based on PVA/LiClO4 nanocomposite reinforced cellulose nanocrystalline from corncob for lithium‐ion battery

AbstractIn the field of high‐energy‐density lithium‐ion battery applications, Polymer electrolyte membranes (PEMs) have garnered significant attention due to their favorable mechanical properties and compatibility with lithium metal anodes. However, their relatively lower ionic conductivity compared to liquid electrolytes, making this problem a challenge for further research. In this study, we present a new approach to overcome these limitations, resulting in PEMs that exhibit exceptional ionic conductivity, flexibility, and interface stability. This achievement was realized by blending polyvinyl alcohol (PVA)/LiClO4 composite reinforced cellulose nanocrystalline (CNC), which is sourced from well and carefully isolated corncob cellulose. PEMs show remarkable improvements regarding ionic conductivity and mechanical strength. Membrane transparency decreased with increasing CNC addition. The maximum improvement mechanical strength was observed with the addition of 5% CNC, namely elongation at break (strain) increased by 15%. At the same composition shows an increase in ionic conductivity to 1.31 × 10−4 S/cm. This study provides the potential of precise material design and composition optimization in overcoming drawbacks associated with conventional PEMs. The findings not only advance the current understanding but also provide a promising avenue for the development of high‐performance PEMs, which are critical for the evolution of future energy storage technologies.

Engineering and Life Cycle Assessment (LCA) of Sustainable Zeolite-Based Geopolymer Incorporating Blast Furnace Slag

This study aims to investigate the preparation of zeolite-based geopolymer composites incorporating blast furnace slag at various temperatures and varying amounts of blast furnace slag as potential sustainable building and construction materials. The primary objectives were to use mining waste streams for geopolymer production and assess the mechanical behavior of these hybrid geopolymers, along with performing a life cycle assessment (LCA) to compare their environmental impact with conventional concrete. It was observed that the hybrid geopolymers attained a maximum mechanical strength of 40 MPa. Remarkably, substituting just 20% of the material with blast furnace slag resulted in a 92% improvement in compressive strength. To assess environmental impacts, a cradle-to-gate LCA was performed on different geopolymer mix designs, focusing particularly on the global warming potential (GWP). The results indicated that geopolymer concrete generated a maximum of 240 kg CO2-e/m3, which was 40% lower than the emissions from ordinary cement, highlighting the environmental advantages of geopolymer materials. Further, X-ray diffraction was used to determine the mineral composition of both raw and developed composites. Solid-state nuclear magnetic resonance (NMR) was applied to study the molecular structure changes upon incorporating blast furnace slag. The initial setting time and shrinkage of the geopolymers were also investigated. Morphological characteristics were analyzed by scanning electron microscopy (SEM). Thermal analyses confirmed the stability of the geopolymers up to 800 °C. Geopolymer composites with high thermal stability can be used in construction materials that require fire resistance. This study not only enhances the understanding of geopolymer composite properties but also confirms the substantial environmental advantages of utilizing geopolymerization in sustainable construction.

Enhancing mechanical performance of TiO2 filler with Kevlar/epoxy-based hybrid composites in a cryogenic environment: a statistical optimization study using RSM and ANN methods

This research aims to investigate the mechanical performance of the different weight proportions of nano-TiO2 combined with Kevlar fiber-based hybrid composites under cryogenic conditions. The following parameters were thus considered: (i) Kevlar fiber mat type (100 and 200 gsm); (ii) weight proportions of TiO2 nanofiller (2 and 6 wt%); and (iii) cryogenic processing time (10–30 min at −196°C). The composites were fabricated through compression molding techniques. After fabrication, the mechanical characteristics of the prepared nanocomposites—such as tensile, bending, and impact properties—were evaluated. The optimal mechanical strength of nanofiller-based composites was analyzed using response surface methodology (RSM) and artificial neural networks (ANNs). Compositions, such as four weight percentages of nano-TiO2 filler, 200 gsm of the Kevlar fiber mat, and 20 min of cryogenic treatment, were shown to produce the maximum mechanical strength (65.47 MPa of tensile, 97.34 MPa of flexural, and 52.82 J/m2 of impact). This is because residual strains are produced at low temperatures (cryogenic treatment) due to unstable matrices and fiber contraction. This interfacial stress helps maintain a relationship between the reinforcement and resin and improves adhesion, leading to improved results. Based on statistical evaluation, the ratio of correlation (R2), mean square deviation, and average error function of the experimental and validation data sets of the experimental models were analyzed. The ANN displays 0.9864 values for impact, 0.9842 for flexural, and 0.9764 for tensile. ANN and RSM models were used to forecast the mechanical efficiency of the suggested nanocomposites with up to 95% reliability.

The effect of halloysite nanotubes reinforced epoxy filler on the crushing behavior of aluminum tubes

AbstractCrash box is one of the equipment to minimize the damage that may occur during an accident in vehicles. Many studies are conducted to improve the performance of crash boxes. Some of these studies were aimed at filling thin‐walled crash boxes. Halloysite nanotubes (HNT) were used as filling material in this study. HNT can be found in nature and is in nanotube structure by nature. For this reason, it is inexpensive compared to other nanotubes like carbon nanotube. Within the scope of the study, epoxy‐based mixtures with 0%, 5%, 10%, and 15% HNT were prepared and filled into aluminum tubes. The powders used were ~20–100 nm in size and in the form of cylindrical tubes. Investigated were the effects of the HNT ratio and the thin‐walled aluminum construction. Nine diverse types of specimens were created. The vacuuming principle was used as the production method. The reason for this is to minimize the air bubbles that may occur during mixing. The effect of aluminum tube and HNT ratio on energy absorption and mechanical strength was investigated. For this, quasi‐static tests were conducted. The absorbed energies of the specimens were determined by integrating the acquired contact force–displacement curves, and the specific absorbed energy was determined by dividing the absorbed energy by the specimen weights. SEM images were taken for internal structure characterization. In addition, FTIR analysis was performed to determine whether the composite was cured. According to the results obtained, the mechanical characteristics and specific absorbed energy of the filled specimens were superior to those of the unfilled ones. Specimen containing 5% HNT showed maximum energy absorption and mechanical strength. Although the HNT additive has a positive effect on the mechanical and energy absorption in general, it has been determined that the HNT additive affects the performances negatively from 10%.

Laboratory study on the effect of stress cycling pattern and rate on seismicity evolution

Recent laboratory and field studies suggest that temporal variations in injection patterns (e.g., cyclic injection) might trigger less seismicity than constant monotonic injection. This study presents results from uniaxial compressive experiments performed on Red Felser sandstone samples providing new information on the effect of stress pattern and rate on seismicity evolution. Red Felser sandstone samples were subjected to three stress patterns: cyclic recursive, cyclic progressive (CP), and monotonic stress. Three different stress rates (displacement controlled) were also applied: low, medium, and high rates of 10−4 mm/s, 5 × 10−4 mm/s, and 5 × 10−3 mm/s, respectively. Acoustic emission (AE) waveforms were recorded throughout the experiments using 11 AE transducers placed around the sample. Microseismicity analysis shows that (i) Cyclic stress patterns and especially cyclic progressive ones are characterized by a high number of AE events and lower maximum AE amplitude, (ii) among the three different stress patterns, the largest b-value (slope of the log frequency-magnitude distribution) resulted from the cyclic progressive (CP) stress pattern, (iii) by reducing the stress rate, the maximum AE energy and final mechanical strength both decrease significantly. In addition, stress rate remarkably affects the detailed AE signature of the events classified by the distribution of events in the average frequency (AF)—rise angle (RA) space. High stress rates increase the number of events with low AF and high RA signatures. Considering all elements of the AE analysis, it can be concluded that applying cyclic stress patterns in combination with low-stress rates may potentially lead to a more favourable induced seismicity effect in subsurface-related injection operations.

Cell-free fat extract-loaded microneedles attenuate inflammation-induced apoptosis and mitochondrial damage in tendinopathy.

Existing clinical treatments for tendinopathy mainly focus on reducing pain, whereas inhibiting or reversing disease progression remains challenging. Local therapeutic drugs, such as glucocorticoids, cause adverse effects on the metabolism of tendon tissues and injection-related complications. Therefore, new administration modalities for tendinopathy need to be developed. In this study, we designed a hydrogel-based microneedle (MN) system for the long-term transdermal delivery of our novel biological cell-free fat extract (CEFFE) to treat tendinopathies. We found that CEFFE-loaded MNs (CEFFE-MNs) had good biosafety and inhibited lipopolysaccharide (LPS)-induced apoptosis and matrix degradation in Achilles tendon cells of rats. The Achilles tendons of rats returned to their maximum mechanical strength after applying CEFFE-MNs. The administration of CEFFE-MNs had better anti-apoptosis and tendon repair-promoting effects than CEFEF injections in vivo. Transcriptome sequencing indicated that the anti-apoptosis effect of CEFFE-MNs was highly related to tumor necrosis factor (TNF) signaling. CEFFE-MNs inhibited the expression of TNF, TNF receptor 1, and downstream nuclear factor-kappa B signaling. Additionally, CEFFE-MNs rescued LPS-induced mitochondrial dynamics in tendon cells via the TNF-Drp1 axis. Our study reports a novel CEFFE-MN system that exhibits long-term anti-inflammatory and anti-apoptotic effects, suggesting it as a new treatment route for tendinopathy with broad clinical translation prospects.

Densely sintered carbide-silicon ceramics on a glass-crystal binder of cordierite composition

The high density of silicon carbide ceramics is a prerequisite for obtaining materials with high strength. A promising technology for preparation of such materials at relatively low temperatures is the use of glass crystal bonds. The paper presents the results of studies on ceramic materials based on silicon carbide using glass in the pseudoternary system MgO–Al2O3–SiO2 as a glass binder. The composition of the glass corresponds to a ternary eutectic with a temperature of 13650C, which is located at the boundary of the primary crystallization fields, where one of the phases is cordierite. It has been determined that it is necessary to mechanically activate the components of the raw material mixture to obtain densely sintered ceramics. In this case, the most rational ratio between SiC filler and glass binder, which provides the maximum mechanical compressive strength (up to 700 MPa), is 60:40. It has been established that the crystallization of the glass binder plays a decisive role in determining the formation temperature of dense silicon carbide materials. The compaction occurs due to the movement of dispersed silicon carbide particles in the softened glass melt under the influence of thermal vibrations. The subsequent process of fine-dispersed crystallization of the glass binder during cooling during firing provides strengthening of the structure of the synthesized materials. The proposed integrated approach to the intensification of the sintering process is promising for obtaining durable silicon carbide ceramics with low synthesis temperatures (up to 16000C). A sufficiently high strength of the experimental ceramics will ensure its competitiveness with respect to traditional materials, including those used as wear and impact resistant.

FABRICATION AND CHARACTERIZATION OF GFRP-POLYURETHANE COMPOSITE SANDWICH PANELS FOR EARTHQUAKE-RESISTANT BUILDINGS

Todays modern house walls use a lot of fabric panels that have good insulating properties, are energy-saving, and are easy to clean and sterilize so the room becomes healthier. These insulator panels are also widely used for earthquake-resistant houses because these materials are light and do not break easily. These panels are often also referred to as composite sandwich panels. The properties of this composite sandwich panel depend on the behavior of the two face layers of the composite material and the lightweight core material as the filler component. This research focuses on fabricating and characterizing sandwich structure glass fiber reinforced polymer (GFRP) composites filled with rigid polyurethane foam. The main objective of this study is to observe the effect of the amount of epoxy resin as a binder between the GFRP face layer and the polyurethane core material on mechanical strength, such as tensile strength, flexural strength, and compressive strength. The test results showed that the maximum mechanical strength was in sandwich panels with the epoxy composition of 2.5 kg/m2 panels, with a flexural strength of 3.68 MPa, compressive strength of 15.53 MPa, and tensile strength of 0.175 MPa. The polyurethane core material is the most fragile part of the composite sandwich panel.

Characterization of Heat-Resistant Insulating Impregnating Varnish Based on Bismaleimide/Diamine Copolymer

With the development of high-voltage electrical equipment towards the direction of higher power density and higher voltage level, it will resulting in the temperature-resistant grade of insulating dip varnish. Bismaleimide (BMI) resin used as the matrix resin of dip varnish solution is widely applied due to its good aging resistance, mechanical properties and dielectric properties. Due to the imide ring structure in BMI resin structure, the bonding energy of chemical bonds in the molecule is higher. The resin reacts less at lower temperatures, resulting in the difficulty of forming and processing. The high crosslinking density of condensates results in unsatisfactory mechanical properties of BMI resin and presents a poor toughness. Therefore, this paper uses Michael addition reaction to prepare branched resin with large free volume from binary amine and BMI resin, and explores various properties of its cured products. The results show that: Using different kinds and different contents of binary amines, its insulation performance was further improved. MT-cured sample had the best comprehensive performance, with a minimum dielectric constant of 3.24. The minimum dielectric loss of BAPP cured sample was 0.00135. The maximum volume resistivity of FDA sample was 2.46×1015 Ω·m and the maximum breakdown field strength of BAPP sample was 29.83 kV/mm; The mechanical properties were significantly improved, and the maximum mechanical strength of the MT samples reached 174.63 MPa.

Mechanical Strengths of Alkali-Activated Blast Furnace Slag Powder with Different Alkali Activators and Plant Fibers

In this paper, the influence of water glass types, the modulus of water glass, the alkali content, the water consumption, and plant fibers on the mechanical strengths of alkali-activated blast furnace slag powder (BFS) is investigated. Moreover, the fiber types and pretreatment on the plant fibers and the measuring temperature on the performance of alkali-activated BFS are further considered. Results indicate that BFS activated by potassium silicate shows higher mechanical strengths than that activated by sodium silicate. The alkali-activated BFS with alkali treatment on fibers is the most advantageous. The modulus of alkali leads to decreasing the compressive strength. A total of 35% water consumption is the most beneficial to the specimens’ flexural and compressive strengths. Samples with 14% potassium silicate show the maximum mechanical strength. Alkali-activated BFS with 1% wheat straw fibers in addition by total volume represents the maximum mechanical strength. The alkali-activated BFS with alkali treatment on fibers is the most advantageous. The addition of potassium silicate can improve the flexural and compressive strengths by the maximum values of 30.4% and 16.8% compared to specimens with sodium silicate. A total of 35% water consumption can increase the flexural and compressive strengths by 33.8% and 32.7%.

Engineering and environmental evaluation of red mud amended volcanic ash as a sustainable subgrade material

With the increasing stockpiles of red mud (RM) and the pollution caused to the environment, there is an urgent requirement to utilize the RM. This research carried out laboratory tests to explore engineering properties and environmental impact of RM-reinforced volcanic ash (VA) as subgrade material. VA is mixed with RM in six proportions (Percentage of RM is 5%, 10%, 15%, 20%, 25%, and 30% by VA weight). According to scanning electron microscope (SEM) images, the RM particles will not only fill the voids among the VA particles, but also fill the pores formed by the broken bubbles in VA particles, which increases the compactness of the specimens. The mixtures contain a small amount of illite, which exhibit the characteristics of non-cohesive soil. The water stability of the specimens is poor, and the strength of specimens diminishes with the increasing water content. When RM content (RMc) does not exceed 15%, the pH values and heavy metal contents of the specimens do not exceed the safety limit values required by the standards. And when RMc is 15%, the specimens obtain the maximum compactness and mechanical strength. Therefore, the optimal amount of RM is about 15%. This study provides a new material selection strategy for road construction in volcanic areas and is the first time to propose the use of RM as an reinforced material for VA. This also enriches the application of RM and solves the problems of resource shortage in volcanic areas, overproduction of RM and environmental pollution caused by storage of RM, which is of great significance for sustainable development and environmental protection.

Light‐Responsive Programmable Shape‐Memory Soft Actuator Based on Liquid Crystalline Polymer/Polyurethane Network

AbstractLiquid crystalline polymers (LCPs), especially liquid crystalline elastomers (LCEs) can generate ultrahigh shape change amplitude but has lower mechanical strength. Although some attempts have been tried to improve the mechanical performance of LCE, there are still limitations including complicated fabrication and high actuation temperature. Here, a versatile method is reported to fabricate light‐driven actuator by covalently cross‐linking polyurethane (PU) into LCP networks (PULCN). This new scheme is distinct from the previous interpenetrating network strategy, the hydrogen bonds and covalent bonds are used in this study to improve the miscibility of non‐liquid‐crystalline PU and LCP materials and enhance the stability of the composite system. This material not only possesses the shape memory properties of PU but shows shape‐changing behavior of LCPs. With a shrinkage ratio of 20% at the phase transition temperature, the prepared materials reached a maximum mechanical strength of 20 MPa, higher than conventional LCP. Meanwhile, the resulting film shows diverse and programmable initial shapes by constructing crosslinking density gradient across the thickness of the film. By integration of PULCN with near‐infrared light‐responsive polydopamine, local and sequential light control is achieved. This study may provide a new route for the fabrication of programmable and mechanically robust light‐driven soft actuator.

Fabrication and finite element simulation of aluminum/carbon nanotubes sheet reinforced with Thermal Chemical Vapor Deposition (TCVD)

This study aims to grow the carbon nanotubes (CNTs) on the aluminum substrate (sheet) using Thermal Chemical Vapor Deposition (TCVD) so that the aluminum sheets can be clad together. Besides, finite element simulation (FEM) was used to evaluate the damage progression, and fracture initiation in AL-CNT composites. AL-CNT Representative Volume Element (RVE) was studied to numerically get an appropriate micro-scale Al-CNT composite simulation. To forecast the statistical connection between material microstructure and effective constitutive properties, the RVE approach was developed. AL/CNT RVE models were studied to determine the most effective carbon nanotube weight percentage as a contender to reinforce the aluminum matrix. The experimental technique was then used to investigate the results found in the RVE models. According to the experimental procedure, AL/CNT shows the maximum mechanical strength and material behavior in the CNT weight percentage reported by the RVE model analysis. Furthermore, regarding the importance of continuum mechanical simulation of microstructural damage processes in the ductile fracture mechanics research, the effect of stress triaxiality ratios, such as the ratio of mean stress to equivalent stress, on the damage growth rate was studied. The experimental results show that the composite mechanical behavior is appropriate at each CNT weight percentage simulations were conducted, and the results were compared to the numerical and experimental approaches in the literature, yielding satisfactory agreements. Based on the experimental findings, ultimate strength and young modulus of AL-5 wt.% CNT are 239 MPa and 73 GPa respectively. By adding more CNT concentration, CNT agglomerations are appeared inside the samples based on SEM. Therefore AL-5 wt.% CNT is the final candidate with the best physical properties.

To investigate the effect of process parameters on the dissimilar welded joint of AA7075 and Cu

The friction stir welding (FSW) is a viable welding process for joining the two dissimilar materials owing to its solid-state nature. The process parameters are very crucial in determining if the FSW process is effective. In the present manuscript aims to investigate the effect of process parameters such as rotational speed (RS), where other parameters were kept constant on mechanical characteristics for the dissimilar welded joint (DWJ) of aluminum AA7075 grade with the pure Cu grade. The RS varies at different level i.e., 900, 1200, 1400 RPM. The findings indicate that changes in RS have a considerable impact on mechanical strength, and 1200 RPM was shown to be the ideal RS number for the maximum mechanical strength.

Development of Bioactive Opuntia ficus-indica Edible Films Containing Probiotics as a Coating for Fresh-Cut Fruit.

Bioactive edible films have received more attention in recent years as a method for food preservation with value-added functions. The aim of this study was to develop a bioactive edible film containing mucilage of cactus (Opuntia ficus-indica) and incorporating the probiotic strain Enterococcus faecium FM11-2 as an active component to promote consumer health benefits. Opuntia ficus-indica is rich in nutritional and bioactive compounds and the abundance of this cactus makes it attractive for food applications. Mucilage of Opuntia ficus-indica contained 0.47 ± 0.06 mg/g total sugar, 0.33 ± 0.06 mg AGE/mL phenolic content, 0.14 mg/ mL vitamin C, and possessed 35.51 ± 1.88% DPPH scavenging activity. The edible film that was developed exhibited the following characteristics: thickness of 0.02-0.11 mm, percent moisture content 0.19-0.24%, water solubility 30.66-59.41% and water vapor permeability of 0.15-1.5 g·mm/m2·min·kpa, while the range of the variation depended on the type of plasticizer used (either sorbitol or glycerol). The addition of sorbitol in the film provided the maximum mechanical strength based on the evaluation of tensile strength, Young's modulus and elongation at break (44.71 ± 0.78 MPa, 113.22 ± 0.23 MPa and 39.47 ± 0.61%, respectively). The optimal formulation of the edible film, according to the physicochemical, physical and maintenance of fresh-cut apple slices, contained cactus mucilage, gelatin, glycerol and a probiotic. The incorporation of a probiotic into the cactus film created a bioactive edible film that could provide a health benefit. While improvement is needed to maintain the survival rate of the probiotic, this work presents an exciting method for furthering the study of food preservation with edible films.