Higher Tensile Strength Values Research Articles

Effect of Elevated Temperature on Microstructure and Mechanical Properties of Hot-Rolled Steel

The mechanical properties and microstructure of hot-rolled steel are critical in determining its performance in industrial applications, particularly when exposed to elevated temperatures. This study examines the effects of varying temperatures and soaking times on these properties through a series of controlled experiments. The primary objective was to optimize the key response parameters, including tensile strength, yield strength, and elongation, by analyzing the influence of temperature and time. A full factorial design approach was used, applying the desirability function theory to explore all possible combinations and identify optimal processing conditions. The experimental results showed that the soaking time played a critical role, significantly influencing the mechanical properties with an impact ratio of 62%. The microstructural analysis displayed that higher temperatures and longer soaking times resulted in the formation of coarser ferrite and pearlite grains, contributing to a decrease in strength and an increase in ductility. The optimum process condition - 650 °C for 60 min - produced the highest values for tensile strength (400.32 MPa), elongation (36.78%) and yield strength (288.52 MPa). The study also highlighted the temperature-dependent nature of the mechanical behavior of hot-rolled steel. While tensile strength and yield strength initially increase with temperature, prolonged exposure, particularly at 600 °C and 750 °C, results in significant grain coarsening and a corresponding degradation of these properties. Conversely, elongation improves at moderate temperatures (150 °C to 300 °C) but decreases with prolonged exposure, especially at higher temperatures. These findings underscore the importance of precise control of thermal processing parameters to optimize the mechanical properties of hot-rolled steel. The findings offer significant insights that can be leveraged to optimize material performance in industrial applications, where thermal exposure is a critical consideration.

High-Strength, Self-Healing Copolymers of Acrylamide and Acrylic Acid with Co(II), Ni(II), and Cu(II) Complexes of 4'-Phenyl-2,2':6',2″-terpyridine: Preparation, Structure, Properties, and Autonomous and pH-Triggered Healing.

The utilization of self-healing polymers is a promising way of solving problems associated with the wear and tear of polymer products, such as those caused by mechanical stress or environmental factors. In this study, a series of novel self-healing, high-strength copolymers of acrylamide, acrylic acid, and novel acrylic complexes of 4'-phenyl-2,2':6',2″-terpyridine [Co(II), Ni(II), and Cu(II)] was prepared. A systematic study of the composition and properties of the obtained polymers was carried out using a variety of physicochemical techniques (elemental analysis, gel permeation chromatography (GPC), attenuated total reflectance Fourier transform infrared spectroscopy (ATR/FT-IR), ultraviolet-visible spectroscopy (UV-vis), small-angle X-ray scattering (SAXS), wide-angle X-ray scattering (WAXS), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), confocal laser scanning microscopy (CLSM), and tensile testing). All metallopolymer samples exhibit autonomous intrinsic healing along with maintaining high tensile strength values (for some samples, the initial tensile strength exceeded 100 MPa). The best values of healing efficiency are possessed by metallopolymers with a nickel complex (up to 83%), which is most likely due to the highest lability of the metal-heteroatom coordination bonds. The example of this system shows the ability to re-heal with negligible deterioration of the mechanical properties. The possibility of tuning the mechanical properties of self-healing films through the use of different metal ions has been demonstrated.

Mechanical Behaviour of Green Epoxy Composites Reinforced with Sheep and Dog Wool from Serra Da Estrela.

Environmental awareness has led industries and consumers to replace products derived from oil resources with products derived from natural sources. In the case of the composite materials industry, the replacement of synthetic fibres with natural fibres has increased in recent years. To study the influence that different types of natural fibres and different textile manufacturing techniques have on the mechanical properties of composites, bio-based epoxy matrix composites reinforced with different natural animal fibres were produced, some reinforced with sheep's wool and others with dog wool, which were later subjected to bending and tensile tests. From the authors' knowledge, there are few studies of composites produced with animal fibres, and even fewer with dog hair. The textile structures used as reinforcement were created using crochet, knitting, and weaving techniques. Prior to the composites production, the fibres were characterized by X-ray Diffraction (X-RD), and the yarns produced from these fibres were subjected to tensile tests. The results obtained suggest that the number of yarns and the diameter of the needles used during the production of the reinforcement have a significant impact on the mechanical properties of the composites. The green epoxy resin composites reinforced with sheep's wool exhibit higher values of flexural strength, tensile strength, and Young's modulus than those reinforced with dog wool, with average increases of 36.97%, 45.16%, and 72.99%, respectively. It was also possible to verify that the composites reinforced with woven fabrics and crocheted fabrics exhibit the highest values of tensile strength, flexural strength, and Young's modulus. Additionally, the composites reinforced with woven fabrics exhibit the highest values of deformation at first failure/break and toughness.

Pengaruh Variasi Sudut Kampuh dan Kuat Arus Pengelasan Hasil Las SMAW Baja SS400 untuk Bahan Bejana Tekan terhadap Kekuatan Tarik dan Kekerasan

A pressure vessel is a closed container that stores pressurized liquids or gases. Low-carbon steel is used as a material for pressure vessels that operate at low to moderate temperatures. One of the important aspects of manufacturing pressure vessels is the welding process. The welded area tends to be the weakest point due to exposure to high heat, which can lead to greater residual stress and potentially cause cracking. This study aims to evaluate the effect of variation in ample angle and current strength on mechanical properties, especially tensile strength, and hardness, to determine the optimal amplitude angle and current strength. The research method applied is an experiment by conducting SMAW welding on SS400 steel using E7016 electrodes, with a single V ample angle variation of 55°, 60°, 65°, and strong welding current of 110 A, 120 A, and 130 A, then a tensile test and hardness test are carried out. The results show that the tensile strength of the raw material is 481.2 with a hardness of 191.95 HVN. For the variation of the amputation angle, the highest tensile strength value was recorded at an angle of 55°, which was 567.471 N/mm2 , while the lowest was at an angle of 65°, which was 559.997 N/mm2 . The highest hardness value at a 65° angle reached 328.422 HVN, while the lowest at a 55° angle was 312.878 HVN. In terms of current strength variation, the highest tensile strength is obtained at 130 A which is 568.421 N/mm2 and the lowest at 110 A is 552.339 N/mm2 . The highest hardness value is found at a current strength of 110 A, which is 343.411 HVN, and the lowest at a current strength of 130 A, which is 295.122 HVN. The optimal parameters were found at a yield angle of 55° with a tensile strength of 567.471 N/mm2 and a hardness of 312.8 HVN and a current strength of 130 A with a tensile strength of 568.421 N/mm2 and a hardness of 295.1 HVN.

The effect of pulverized glass waste particle sizes on the mechanical properties of AA6061-T6 friction stir welded joints.

Abstract The study sought to investigate the effect of pulverized glass waste (PGW) particle size as reinforcement for AA6061-T6 joints produced by Friction Stir Welding. The study utilized three particle sizes of 15 microns, 45 microns and 75 microns of the PGW as reinforcement alongside the established process parameters ranges of 900-1400rpm, 25-63mm/min and 1-2.5° in a Taguchi L9 orthogonal array for the welding process experimental design. The welding experiments were repeated for each reinforcement particle size mentioned above. Parallel-hole reinforcement strategy was used on all joints for the application of the PGW, Tensile strength, Hardness tests and Microstructural Analysis were carried out on the welded joints and subsequently, analysis of the data. For tensile strength, several sample sets showed a trend of higher tensile strength the smaller the PGW particles size (Figure 6). For hardness, however, there was no overall, discernable trend/pattern of increase in hardness as the particle size decreased. The highest average tensile strength value obtained was 85.25MPa. The lowest tensile strength was 14.26MPa. A distinguishing feature between the highest and lowest value for tensile strength is that the former was obtained with a traverse speed of 25 mm/min while the latter was obtained using a 40 mm/min traverse speed. The higher the rotational speed of the tool pin, the greater the heat of friction generated while the lower the traverse/welding speed, the greater the heat of friction generated as the tool pin spends enough time per unit length to generate sufficient heat and cause plastic deformation sufficiently high enough to cause grain refinement. Using imageJ, percentage distribution of PGW for each crucial zone (Nugget/Stir zone, Thermo mechanically affected zone and Heat affected zone) of the FSWed joint was generated for samples selected for microstructural analysis. The average value for each sample was obtained as well. The highest tensile strength value (85.25MPa) was obtained with a sample using the smallest PGW size (15 µm), in line with the trend (figure 6) in which tensile strength was greater the smaller the PGW size used. The highest hardness value (90.90 BHN) was obtained with the sample having the highest average value for percentage distribution of the PGW (58.06%). A distinct trend was noted in which the greater the percentage distribution of the PGW, the higher the hardness value obtained (figure 30).

EXPERIMENTAL AND OPTIMIZATION-BASED ANALYSIS TO MAXIMIZE MECHANICAL-RELATED ATTRIBUTES OF FRICTION STIR WELDED CDA101 CU ALLOY JOINTS

This paper deals with the identification of optimized process parameters for FSW of 6[Formula: see text]mm thick CDA 101 Cu alloy plates. Three distinctive parameters, the tool’s traverse speed, rotational speed, axial load, have been considered as self-reliant variables for formulating a numerical model based on nonlinear regression-type approach, with the objective of anticipating mechanical attributes of joints. From the surface- and contour-type plots, it was revealed that the axial load in combination with rotational speed has played a dominant role in influencing the tensile and yield strength of the CDA101 Cu alloy joints. At the same time, the traverse speed of the tool has played a dominant role in enhancing the ductility of the CDA101 joints through the generation of ample volumes of frictional heat, which in turn have facilitated both coarsening of grain structures and softening of materials in an ideal manner. Employing tool rotational speed, traverse speed and axial load in the ranges of 1750–1900[Formula: see text]rpm, 23–27[Formula: see text]mm/min and 5.75–6.5[Formula: see text]kN, respectively, was found to enhance the tensile strength of the CDA101 Cu alloy joints. FSW process parameters attained through the numerical meta-model of RSM have led to the attainment of the highest value of tensile strength of 209.5[Formula: see text]MPa together with a 141.4[Formula: see text]MPa yield strength with very minimal fitting errors of 0.28% and 0.52%, respectively. A collection of additional experimental data has been employed to verify the formulated empirical-based formula and additionally, an entirely different optimization technique namely PSO (i.e. particle swarm optimization) was implemented for comparison and validation purposes. The formulated meta-model of RSM generated the largest value of % of elongation of 14.23%, though the relative percent error was around 1.988%, which was slightly larger than that of the value (i.e. 14.11%) generated by PSO, with a relative error of 0.58%.

Composite cellulose/bismuth/PVA nanocrystal for high-performance X-ray radiation shielding

The strong penetrating power of X-rays causes serious health problems. Longer exposure to radiation that penetrates normal cells can result in gene mutations, cancer, and even death. Protection against radiation exposure is necessary to prevent negative impacts from occurring. This research aims to make apron samples using a simple method based on cellulose as a matrix, bismuth as a filler with concentrations of 1 g, 0.75 g, 0.25 g and PVA acts as a binder that helps bind cellulose and bismuth particles into an effective X-ray radiation shield. The characterization carried out includes Fourier transform infrared (FTIR) to determine the functional groups and chemical composition of the sample, x-ray diffraction (XRD) to analyze the crystal size of the sample, and mobile x-ray with energies of 60, 70, and 80 keV to determine the radiation shielding performance. The findings of this study highlight that the optimal shielding properties were attained by employing a sample with the highest concentration of bismuth filler, specifically at 1 g. This material exhibits outstanding characteristics, including a high linear attenuation coefficient and mass attenuation coefficient of 0.68 cm−1 and 2.24 cm2/g respectively for an energy of 60 keV and especially low HVL (1.01 cm) and TVL (3.36 cm) values. These findings have significant implications for developing high-performance X-ray radiation shielding materials, particularly in industries where radiation exposure is a concern, such as the medical industry, research, and laboratories. The high tensile strength (2.83 N/mm2) and elongation (12.09 %) values as well as the low Young's modulus (0.108 N/mm2) values also indicate the flexibility of the resulting material, which could be beneficial for applications that require flexible shielding materials. The practicality of this research makes the audience feel that the findings are applicable and useful in real-world scenarios.

Nanocomposites based on MWCNT and nanoclay: Effect of acrylated epoxidized soybean oil on curing and composite properties

UV and thermal-curing hybrid epoxy adhesives are generally developed with a combination of epoxy acrylates and thermal-curing epoxy resin. This study modified bisphenol-A type epoxy resin (ER) with acrylated epoxidized industrial crop soybean oil (AESO) to obtain a dual-curable epoxy system. Hydroxylated multi-walled carbon nanotube (MWCNTOH) and montmorillonite-type nanoclay (NC) first was used as nano reinforcement in this system. Both thermal and UV-curing were applied to composites. Tensile and hardness tests, thermogravimetric analysis (TGA), and four-point probe electrical conductivity measurements were used for the nanocomposite characterization. Although (UV+thermal) curing increased the thermal strength of the nanocomposites, it caused a decrease in their electrical conductivity and moisture absorption. The highest tensile strength values were obtained as 107 MPa and 97 MPa for thermally cured 1.5 wt% MWCNTOH and 2 wt% NC composites, respectively. The effect of the AESO ratio on UV curing of nanocomposites was investigated and 10 % was found to be the most suitable. MWCNTOH composites also exhibited the highest electrical conductivity with a percolation threshold of 1.5 wt%. The effect of hydrothermal aging on thermal and electrical conductivity properties showed that only T5 and T10 values of thermally or (UV+thermally) cured MWCNTOH and NC composites decreased, T50 values did not change significantly.

Modeling and Prediction of The Mechanical Properties of Feedstock by Cooling-Slope Casting Process using MOJaya Algorithm

Cooling-slope (CS) casting parameters optimization is very challenging due to the uncertainties of parameter values that are influenced by many factors. Therefore, a combination of estimation and optimization models that can solve multi-objective problems using limited data is proposed to reduce the real casting operational cost and time. In casting optimization, modeling and optimization of CS parameters have been considered to identify optimal CS parameters that would lead to better feedstock performance. Computational techniques have been suggested by previous researchers to solve the optimization in the manufacturing process. The study assessed the CS process to determine the feedstock's quality by evaluating its mechanical qualities, namely Tensile strength and Impact strength. Hence, computational methods namely the MOJaya algorithm are utilized to model and optimize the parameters of CS to address the CS problem and forecast the performance of the feedstock. This work conducted a thorough analysis of the impact of CS process parameters on the tensile strength and impact strength using an experimental design. The experiment was conducted using a three-level full factorial design (FFD) of the experiment (DOE), for the parameters of pouring temperature, slanting angle, and pouring distance. The modeling technique involved the development of multiple polynomial regression (MPR) as an objective function in the MOJaya Algorithm. The outcome of the optimization procedure revealed that the optimal solutions obtained from MOJaya were projected to surpass both the initial experimental data and the MOJaya algorithm in terms of the highest values of tensile strength and impact strength. The difference between the two sets of values is 10.92% and 15.76%, respectively. Subsequently, this technique may be employed by a caster to forecast the performance of the feedstock without using repeated experiments that are costly and time-consuming.

Development and characterization of innovative bio-based edible films supplemented with cell-free supernatant and whole-cell postbiotic of Lactobacillus gasseri

More recently, the concepts of cell-free supernatants (CFS, so-called postbiotics) and whole-cell postbiotics (WCP) of probiotics have gained increasing attention for the development of bio-based films. However, reports on CFS and WCP of Lactobacillus gasseri remain scarce. In this study, pea protein isolate/psyllium mucilage was incorporated with CFS and WCP of L. gasseri to produce bio-based edible films. pH, total soluble solid content, antioxidant activity, total phenolic content, antimicrobial activity, and structural analyses were conducted to characterize the CFS and WCP of L. gasseri. Furthermore, the effects of CFS (10% and 20%, v/v) and WCP (10% and 20%, v/v) on the physicochemical, mechanical, barrier, optical, microstructural, and antimicrobial properties of the bio-based films were investigated. The results showed that CFS and WCP exhibited antioxidant and antibacterial activities and were significant sources of phenolic compounds. The incorporation of 20% WCP caused a significant increase in the thickness and water vapor permeability of films, while a significant increase in moisture content was observed with 10% WCP. The control and 10% WCP films had the highest tensile strength values. Furthermore, the addition of 10% WCP resulted in a significant increase in elasticity. Films incorporating CFS and WCP exhibited lower opacity values and darker, yellow, and red color intensities. The addition of CFS and WCP caused a rough texture and cracked structure on the surface of the film. In conclusion, pea protein/psyllium mucilage-based films containing CFS and WCP of L. gasseri can be considered as a new alternative for environmentally friendly bio-based films.

Pyrogallic acid–compatibilized polylactic acid/thermoplastic starch blend produced via one-step twin-screw extrusion

In this study, a one-step extrusion method is proposed to prepare blended polylactic acid (PLA)/thermoplastic starch (TPS) using a novel plant-derived compatibilizer, pyrogallic acid (PGA), to enhance the PLA/TPS compatibility. The effects of PGA on the mechanical behavior, fractured cross-section morphology, thermal and dynamic mechanical performance, and water resistance of PLA/TPS blends were systematically studied. Results demonstrate that the addition of PGA effectively improves the compatibility between TPS and PLA, resulting in enhanced tensile strength, crystallinity, elongation at break, thermal stability, and hydrophobicity of the blends. Specifically, incorporating 1.5 phr of PGA into the blend system yields the highest values for tensile strength (23.38 MPa) and elongation at break (16.96 %), which are 24.7 % and 233.2 %, respectively, higher than those observed for pure PLA/TPS blends. Furthermore, other properties exhibit obvious improvements upon incorporation of PGA into the blends. This approach provides a promising strategy for enhancing the performance of PLA/TPS blends and expanding their applications in food packaging, agricultural film, etc.

Mechanical and Thermal Properties of 3D-Printed Acrylonitrile Butadiene Styrene Reinforced with Rubberwood Fiber

An additive manufacturing (AM) has become very popular due to its simplicity in producing complicated products using just one process due to the layer-by-layer addition of material, which makes it possible for more complicated products to be created. The constraint of Fused Filament Fabrication (FFF) printed components with inadequate mechanical qualities has prevented AM from being widely adopted by numerous industries. The mechanical and thermal qualities of FFF printed components which is a pure polymer could be enhanced by reinforcing the wood fiber into the polymer. In this study, the twin-screw extruder was used to produce the wood plastic composites (WPCs) filaments, which were made with ABS (Acrylonitrile Butadiene Styrene) as the matrix material and 1-3wt% rubberwood fiber (RWF) for reinforcement. The effects of the extrusion parameter, such as the volume fraction of RWF and the temperature of the extrusion process, on the 3D-printed WPCs samples were investigated. The experimental results of 3D-printed WPC sample were found that the highest compressive strength value is 24.3 MPa, obtained from the rubberwood 1wt% at the extrusion temperature 218 °C whereas the pure ABS filaments obtaining from the commercial and extrusion process gave the values of 28.9 and 14.5 MPa, respectively. The highest value of tensile strength is 8.4 MPa with the rubberwood 2wt% and temperature 198 °C whereas the pure ABS filaments obtaining from the commercial and extrusion process gave the values of 10.9 and 7.4 MPa, respectively. The morphological analysis of the 3D-printed WPC sample was observed to exhibit an effect of printing process. The result showed that an increasing temperature of extrusion process increases both tensile and compressive strengths of the samples whereas an increasing amount of fiber increases the tensile strength but decreased the compressive strength. Analysis of variance demonstrated linear factor and 2-way interaction factor of the extrusion parameter influence on compression and tensile strength significantly. The rubberwood 2wt% and the temperature 218 °C was suggested to achieve the suitable condition for extrusion process for the 3D-printed WPC sample. In addition, the discussions were supported with the thermal properties achieved from Thermogravimetric analysis and Differential Scanning Calorimetry.

Self-Organization of Polyurethane Ionomers Based on Organophosphorus-Branched Polyols.

Based on organophosphorus branched polyols (AEPAs) synthesized using triethanolamine (TEOA), ortho-phosphoric acid (OPA), and polyoxyethylene glycol with MW = 400 (PEG), vapor-permeable polyurethane ionomers (AEPA-PEG-PUs) were obtained. During the synthesis of AEPAs, the reaction of the OPA etherification with polyoxyethylene glycol was studied in a wide temperature range and at different molar ratios of the starting components. It turned out that OPA simultaneously undergoes a catalytically activated etherification reaction with triethanolamine and PEG. After TEOA is fully involved in the etherification reaction, excess OPA does not react with the terminal hydroxyl groups of AEPA-PEG or the remaining amount of PEG. The ortho-phosphoric acid remaining in an unreacted state is involved in associative interactions with the phosphate ions of the AEPA. Increasing the synthesis temperature from 40 °C to 110 °C leads to an increase in OPA conversion. However, for the AEPA-PEG-PU based on AEPA-PEG obtained at 100 °C and 110 °C, ortho-phosphoric acid no longer enters into associative interactions with the phosphate ions of the AEPA. Due to the hydrophilicity of polyoxyethylene glycol, the presence of phosphate ions in the polyurethane structure, and their associative binding with the unreacted ortho-phosphoric acid, the diffusion of water molecules in polyurethanes is enhanced, and high values of vapor permeability and tensile strength were achieved.

Microstructure and Tensile Properties of Ni-Base Superalloy IN738LC according to Solidification Rate and Heat Treatment

The strength of Ni-base superalloys mainly depends on the γ' precipitates that improve the strength of the materials at high temperatures. The presence of γ' particles within the matrix restricts dislocation movement, and optimized heat treatments can tailor the size, shape, and volume fraction of γ'. In this study the effects of solidification rate and solution temperature on the tensile properties of IN738LC superalloy were investigated. The secondary dendritic arm spacing of casting materials with different diameters was measured and the solidification rate of the casting materials was derived by comparing the results of the solidification microstructure obtained from a directional solidification experiment. The D17 material, which had a faster solidification rate, showed higher values of tensile strength and yield strength than the D60 material, which had a slower solidification rate. The study also concluded that the monomodal γ' precipitates in the S80 material have higher tensile strength and yield strength at room temperature and 760℃ than the bimodal γ' precipitates in the S20 material. As for the deformation behavior at 760℃, an isolated stacking fault was observed in the S20 material only within the large γ’ precipitates. In the S80 material, the high dislocation density increased the yield strength due to the strong interaction between dislocations and fine γ’ precipitates.

Effect of Layers on Delamination and Tensile Strength of Woven Fiber Composites with Polyester Matrix

A composite is a combination of 2 or more different materials. The composite joining process can use adhesives or mechanically by making holes. During the process of making holes in the composite, it can cause delamination in the composite. Delamination and layer thickness greatly influence the strength of hollow composite joints. This research aims to determine the effect of delamination factors and the number of layers on the tensile strength value of the composite. The materials used in this research are polyester resin and woven glass fiber. The method used is vacuum bagging with variations in the number of layers, namely 3 layers, 4 layers, 5 layers, and 6 layers. Tensile testing refers to ASTM D638 standards. Specimens that have been cut according to standards will then be perforated in the center with a hole diameter of 4 mm using a milling machine. The highest tensile strength value was obtained in the 6-layer variation of 237.448 MPa and the lowest value was obtained in the 3-layer variation of 186.221 MPa. The delamination value greatly influences the tensile strength of the composite, where the more layers, the delamination value will decrease and increase the tensile strength of the composite.

Impact of sulfur compounds on motorbike wheel damper rubber manufacturing materials with 3 Phr, 4 Phr, and 6 Phr compositions

Rubber force is a simple but important thing for vehicles. This component is located in the rear wheel drum which is directly connected to the gear. Many factors influence the damage to this component. This research aims to determine how much influence stearic acid has on the hardness and tensile strength values of the lifting rubber compound. The materials used to make the compound are rubber smoked sheet (RSS) and synthetic rubber mixed with the chemicals stearic acid, black carbon white oil, ZnO, paraffin wax, MBTS, comaron resin and sulfur. These ingredients are mixed using two roll mixing until they combine and form a compound sheet. To determine the maturation time of rubber, a rheometer process is carried out. The next process is vulcanization of rubber using a mold that is pressed at a temperature of 1600C and a pressure of 150 psi. Tensile testing uses rubber testing equipment with SNI ISO 37: 2015 (IDT–2011) standards. Hardness testing uses a tool with a Shore A hardness tester scale with ISO 7619–1:2010 standards. Based on the results of the tests carried out, the addition of sulfur has a very significant effect on the hardness value and tensile strength value. For the hardness value of compound 3 with a sulfur composition of 6 phr, it has the highest hardness, namely 77 Shore A and the lowest value is composition 1 with a hardness value of 65.6 Shore A. The highest tensile strength value is 15,394 N/mm2 in composition 1 and the lowest value is in composition 3 with a value of 11.44 N/mm2

The effect of papaverine on tendon healing and adhesion in rats following Achilles tendon repair.

The study aimed to examine the histopathological and biomechanical effects of papaverine administered intraperitoneally and locally on Achilles tendon healing in a rat model. Forty-eight adult male Sprague-Dawley rats (range, 300 to 400 g) were used in this study conducted between October and November 2022. The rats were divided into three groups, with each group further subdivided into two for sacrifice on either the 15th (early period) or 30th (late period) day after surgery. The first (control) group received no treatment following Achilles tendon repair, while papaverine was intraperitoneally administered every other day for 10 days in the second group and locally in the third group after surgery. On the 15th and 30th days, the rats were sacrificed, and their Achilles tendons were subjected to biomechanical testing and histopathological evaluation. Histopathologically, there were no significant differences among the groups on the 15th day. However, on the 30th day, the locally applied papaverine group exhibited superior histopathological outcomes compared to the control group (p<0.05). Concerning the highest tensile strength values before rupture, the biomechanical assessment showed that the group receiving local papaverine treatment in the early period and both the group with systemic papaverine treatment and the one with local papaverine treatment in the late period displayed a statistically significant advantage compared to the control group (p<0.05). Locally administered papaverine has positive biomechanical effects in the early period and exhibits a positive correlation both histopathologically and biomechanically in the late period. Novel therapeutic options may be provided for patients through these findings.

Physicomechanical, water absorption and thermal properties and morphology of Paederia foetida fiber–Al2O3 powder hybrid‐reinforced epoxy composites

AbstractHybridization of natural fibers with ceramic materials for reinforcing composites allows the optimization of the properties of these materials. For this reason, the present study aims to investigate physical, mechanical, water absorption, swelling and thermal properties as well as morphological characteristics of a hybrid Paederia foetida fibers–alumina powder (PFs–Al2O3)‐reinforced epoxy composite. Epoxy resin served as the matrix, while PFs and Al2O3 were employed as reinforcement. Five types of composites were fabricated using the hot‐pressing technique. The corresponding ratios of PFs:Al2O3 volume fractions (%) considered here were 0:40 (SFA), 10:30 (SFB), 20:20 (SFC), 30:10 (SFD) and 40:0 (SFE). The results reveal that the density of the hybrid PFs–Al2O3 composites decreased for increasing volume fractions of PFs: from 2.173 g cm−3 of SFA to 1.042 g cm−3 of SFE. The highest values of tensile strength (i.e. 49.085 MPa), tensile elastic modulus (i.e. 1.431 GPa) and impact strength (24 kJ m−2) were obtained for the SFD composite material with 30% volume fraction of PFs and 10% volume fraction of Al2O3: this happened because interface bonds between PFs, Al2O3 and epoxy phases achieved their optimal configuration. Overall, mechanical properties of the hybrid PFs–Al2O3‐reinforced epoxy composites were superior to those of composites reinforced only by PF fibers or only by Al2O3. Water absorption and swellability reached their maximum values at the steady state occurring after tested samples remained immersed in water for 820 h. The SFE composite reinforced only by PFs presented the highest water absorption and swelling (i.e. 6.034% and 5.81%, respectively) while for all other hybrid composites (SFD, SFC and SFB) these two quantities remained below 5%. Density and volume fraction of voids of hybrid PFs–Al2O3‐reinforced composites were consistent with the corresponding properties of the composites reinforced only by Al2O3 or PFs. SFD was also the most thermally stable material. Scanning electron microscopy observations of fractured surfaces indicated that the microstructure of the PFs–Al2O3‐reinforced epoxy composites presents several voids, fiber pullouts and transverse fibers, which together optimize the mechanical response of the composite material. Remarkably, the SFD composite material was highly competitive with the most recently developed hybrid composites employing natural reinforcements. © 2024 Society of Industrial Chemistry.

Analisys of Tensile Strength, Wear Rate, and Cristallinity of Biocomposite Nano-HA/Magnesium/Shellac Reinforced Cantula Fiber for Bone Screw Material

Accidents are a major cause of fractures in Indonesia. One of the treatments for fractures is bone screws with support plates that are placed on broken bone. Currently, many biomaterials for bone screws are being developed which have biodegradable properties so that post-operative bone healing is not required. The purpose of this study was to determine the effect of cantula fiber addition on tensile strength, wear rate, and crystallinity of nano-HA/magnesium/shellac bio-composite for bone screw materials. Nano-HA/magnesium/shellac/cantula fiber materials were mixed using a blender. The material was mixed with a magnesium/hydroxyapatite ratio of 70/30 and cantula fiber was added with variations of 0%, 10%, 20% and 30% of total volume. After that, material mixture was compacted with a pressure of 300 MPa for 10 minutes. Then sintering process was carried out at temperature of 140 °C for two hours. The results showed that the highest tensile strength value was 7.86 MPa at 30% variation. The lowest wear rate was 0.31 x 10&lt;sup&gt;-3&lt;/sup&gt; mm&lt;sup&gt;3&lt;/sup&gt;/Nm at 30% variation. The highest crystallinity in X-Ray Diffraction observations was obtained at 30% variation, which was 79.65%.

Efektivitas Hasil Pengelasan SMAW pada Baja ST 37 Dengan Variasi Jenis Elektroda dan Kuat Arus Terhadap Pengujian Tarik dan Korosi Bermedia Larutan H2 S0_4

To support the rapid development of industry at this time, especially in the machinery industry, it has also spurred the development of technology for making basic materials such as steel. ST 37 steel is steel produced for making various machinery components. To improve the mechanical properties of ST 37 steel, a heat treatment process is applied. To see the service life of steel, it is also necessary to pay attention to the rate of corrosion that will occur in the steel that will be used in machine components. The aim of this research is to determine the use of the right type of electrode and current strength to achieve its effective use, with the criteria that the steel has tensile strength when a tensile reaction occurs in the steel and the steel has good corrosion resistance. In this study, the electrode variations used were AWS E6010, E6013, and E7016 electrodes, with variations in current strength of 70 A, 85 A, and 110 A. The highest tensile strength values ​​during the drawing process occurred in specimens with strong AWS E7016 electrode variations. The current was 110 A. Meanwhile, the lowest tensile strength occurred in the specimen with the AWS E6013 electrode variation with a current strength of 70 A. The highest corrosion rate value occurred in the AWS E6010 electrode variation specimen with a current strength of 70 A, while the lowest corrosion rate occurred in the specimen. with AWS E7016 electrode variations with a current strength of 110 A.