Higher Tensile Strength Values Research Articles

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.

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.

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.

Optimization of a Tapered Specimen Geometry for Short-Term Dynamic Tensile Testing of Continuous Fiber Reinforced Thermoplastics

Continuous fiber reinforced thermoplastics (cFRTP) are one of the most promising lightweight materials. For their use in structural components, reproducible and comparable material values have to be evaluated, especially at high strain rates. Due to their high stiffness and outstanding strength properties, the evaluation of the material behavior at high strain rates is complex. In the presented work, a new tensile specimen geometry for strain rate testing is virtually optimized using a metamodel approach with an artificial neural network. The final specimen design is experimentally validated and compared with rectangular specimen results for a carbon fiber reinforced polycarbonate (CF-PC). The optimized specimen geometry leads to 100% valid test results in experimental validation of cross-ply laminates and reaches 9% higher tensile strength values than the rectangle geometry with applied end tabs at a strain rate of 40 s−1. Through the optimization, comparable material parameters can be efficiently generated for a successful cFRTP strain rate characterization.

Pemanfaatan Pati Sagu (Metroxylon sago) dan Limbah Kulit Jeruk Sebagai Bioplastik Pembungkus Makanan (Edible Film) Ramah Lingkungan

The increasing use of plastic harms the environment because plastic has properties that are difficult to degrade, resulting in environmental pollution, while the demand for plastic is increasing day by day. Bioplastics are a form of innovation from technological developments in modern times. One example of bioplastic is edible film which can function as food packaging that can be consumed. Edible film made from sago starch and orange pectin is believed to be able to produce edible films that have good characteristics. The results of this study, all nine treatment variations did not meet the standards for bioplastics that had been determined by SNI and JIS. The highest tensile strength values were obtained from testing variations in the concentration of 6% sago starch and 2% orange peel pectin (8,643 Mpa), while the highest elongation values were obtained from 4% sago starch and 2% orange peel pectin (5,33%.). Based on the results of the edible film using sago starch and pectin, it showed that more pectin content decrease the biodegradation rate.

Pengaruh Penambahan Serat Kulit Jagung Terhadap Sifat Mekanik Komposit Polipropilena (PP) dengan Penambahan Aluminium Oksida (Al2O3) dan Maleat Anhidrida (MAH) sebagai Coupling Agent

The utilization of polymer composites in the automotive field is expanding due to their characteristics such as strength, stiffness, and light weight. Polypropylene (PP) is one of the thermoplastic polymers widely used in composite manufacturing due to its lightweight, corrosion-resistant, and recyclable properties. However, to improve its mechanical properties, modifications using natural reinforcements and coupling agents continue to be made. Corn husk fiber is a natural resource that has potential as a natural reinforcement in polymer composites, it has the advantages of good tensile strength, light weight, and is biodegradable. The addition of Aluminium Oxide (Al2O3) and Maleic Anhydride (MAH) as coupling agent can improve the adhesion between fiber and polymer matrix, support more even load distribution, and optimize the mechanical properties of the composite Al2O3 and MAH on the mechanical properties of PP composites. The composition used was polypropylene: corn husk fiber rasio :Al2O3: MAH, namely 90:5:5:0, 89:5:5:1, 87:5:5:3, and 85:5:5:5% by weight. Tensile strength test using Universal Testing Machine (UTM) and crystallinity test using Differential Scanning Calorimetry (DSC) were conducted to evaluate the material performance. The highest value of tensile strength and crystallinity in the composition with 0 %weight MAH. The results of these tests, showing that the greater the composition of corn husk fiber has an influence on the decrease in tensile strength and crystallinity of the composite.

Supramolecular/Dynamic Covalent Design of High-Performance Pressure-Sensitive Adhesive from Natural Low-Molecular-Weight Compounds.

Adhesive materials have played an essential role in the history of humanity. Natural adhesives composed of low-molecular-weight monomers have been overshadowed by modern petroleum-based glues. With the development of green economy, the demand for eco-friendly materials has increased. Herein, two natural biocompatible compounds, namely thioctic acid (TA) and malic acid (MA), are selected to prepare a high-performance pressure-sensitive adhesive poly[TA-MA]. This adhesive can be quantitatively obtained via a simple mixing and heating process. Poly[TA-MA] shows interesting and useful properties, including reversible flexibility, high elongation, and good self-healing, owing to its dynamic polymerization pattern and reversible cross-linking behavior. Poly[TA-MA] exhibits excellent adhesion performance under various extreme conditions, such as at low temperatures and in hot water. High values of shear strength (3.86MPa), peel strength (7.90Ncm-1 ), loop tack (10.60Ncm-1 ), tensile strength (1.02MPa), and shear resistance (1628h) demonstrate the strong adhesive effect of poly[TA-MA]. Additionally, TA can be regenerated in the monomer forms from poly[TA-MA] with high recovery rate (>90%). Meanwhile, strong anti-bacterial behavior of poly[TA-MA] is recorded. This study not only reported a new pressure-sensitive adhesive but also fully displayed the feasibility of using natural small molecules to achieve robust surface adhesion.

Effects of Process Parameters in Thermoforming of Unidirectional Fibre-Reinforced Thermoplastics.

Process-induced defects during thermoforming are widespread problems in laminate manufacturing. The aim of this study is to describe the effects of holding time and pressure on several properties of the manufactured laminate. A design of experiments is performed, followed by an analysis of variance to examine significant effects. Subsequently, a regression model is created to predict the laminate's properties, which is also validated. A significant interaction between holding time and pressure is determined for the resulting tensile strength and elongation at break with a p-value of 1.52·10-16 and 0.02, respectively. The highest values of tensile strength and elongation at break are found for low settings of holding time and pressure. The fibre volume fraction is not affected by the process parameters. As holding time and pressure increase, significant fibre misalignment takes place, leading to a decrease of the mechanical properties. The regression model corresponds well with the validation and a tensile strength of 1049 MPa with an elongation at break of 2.3% is reached.

Optimization of Unsaturated Polyester Resin Matrix Composite Materials Reinforced Banana (Musa Balbisiana) Fronds Composition Towards Tensile Test

This study aims to find out how the physical and mechanical properties of banana tree frond fibers are strengthened by a polyester matrix with various variations of fiber fractions. The study began by making three types of specimens with differences in volume fractions, namely 6% fiber + 94% matrix, 9% fiber + 91% matrix and 12% fiber + 88% matrix with the hand lay – up method. The results of making composites are carried out physical properties testing in the form of density testing, water absorption and thick development and mechanical testing with tensile tests. The results of the physical properties test show that the average density value of each volume fraction variation is above the JIS A509 – 2003 standard. The water absorption value and the thick development of the three fraction variations are still below the maximum limit. While in mechanical properties testing, the highest tensile strength value was obtained at a volume fraction of 12% fiber + 88% matrix with an average tensile strength value of 37.28 MPa.

Synthesis and characterization of new electrospun medical scaffold-based modified cellulose nanofiber and bioactive natural propolis for potential wound dressing applications.

Recently, the design of polymer nanofibers using the electrospinning process has attracted much interest. Particularly the use of natural polymers has promoted many advantages in their biomedical applications. However, the combination of multiple natural polymers remains a great challenge in terms of electrospun production and applied performance. From this perspective, the current investigation highlights the study of the preparation of electrospun nanomaterial scaffolds based on combined natural polymers for improved wound healing performance. First, we have synthesized a crosslinked polymer by reacting microcrystalline cellulose (MC) and chitosan (CS) biopolymer via the intermediate of citric acid as a crosslinking agent. Then a natural propolis biomolecule was incorporated into the polymer network. Different MC/CS blend ratios of 90/10 and 70/30 were then used and various machine parameters were optimized to obtain nanofiber scaffolds with excellent strength and structures. SEM, IR, physicochemical, mechanical, and morpho-logical characterization were then performed. SEM evaluation revealed homogeneous and bead-free nanofibrous structures, with well-defined morphology and a random deposition that could accurately mimic the extracellular matrix of native skin. The calculated average nanofiber diameters for the MC/CS blend ratios at 90/10 and 70/30 were 431.4 and 441.2 nm, respectively. The results showed that when the chitosan amount increased, larger nanofibers with narrow diameter distribution appeared. The prepared nanomaterials had a significant and close water vapor permeability of about 1735.12 and 1698.52 g per m per day for the two blend ratios of 90/10 and 70/30, respectively. The examination of swelling behavior revealed a noteworthy enhancement in hydrophilicity, a necessary attribute for improved healing efficacy. FT-IR analysis confirmed the success and the stability of the chemical crosslinking reaction between the two biopolymers before nanofiber conception. Excellent mechanical properties were acquired, based on the chitosan content. Both developed nanofiber scaffolds exhibited high tensile strength and Young's modulus values. The incorporation of 30% chitosan versus 10% results in an increase in tensile strength of 11% and 14% in Young's modulus. Therefore, we could adjust the different mechanical properties simply by varying the mixing rate of the electrospun polymers. Using epithelial HepG2 cells, viability and kinetic cell adhesion assays were assessed to obtain biological evaluation. No cytotoxicity was observed and good cytocompatibility was confirmed. Functionalized nanofiber biomaterials with different MC/CS ratios substantiated significant bactericidal effectiveness against Gram-positive and Gram-negative bacterial culture strains. The novel functional electrospun wound dressing scaffold demonstrated effective and promising biomedical performance, healing both acute and chronic wounds.

Review of MIG and TIG welding current variation of low-carbon steel materials based on tensile strength

SS400 and ASTM A36 a low-carbon steel materials that are used in the industry in the connection process to create materials according to the design. The aim of this research is to review the mechanical properties that occur in low-carbon steel materials in the MIG and TIG welding process with current variations and provide advice on low-carbon steel in welding. The materials used are ASTM A 36 and SS 304 steel. MIG welding uses a plate with a thickness of 6mm and uses AWS A5.18 ER 705-6 electrode diameter of 1.2mm. TIG welding uses a cylinder with a diameter of 6mm. The method of this review reported the tensile strength of low-carbon steel ASTM A36 with current variations of 150, 155, and 160A for MIG. Current variations of SS304 low-carbon steel are 80, 100, and 120A for TIG. The result of tensile strength with the MIG process produces the highest average current of 150 A of 354.92MPa. The results of tensile strength TIG process for 100A of 1007.31 MPa. The suggestion of this review is in MIG welding a greater current is required to obtain a high tensile strength value than the current required for TIG welding on low-carbon steel ASTM A 36 with a carbon content of 0.29% C and on SS304 with a carbon content of 0.042% - 0.07% C. Welding for stainless steel material can be used on TIG welding to get maximum tensile strength values. For ASTM A36 steel materials, MIG welding can be an option.