Higher Tensile Strength Values Research Articles

Mechanical and Thermal Behaviour of Rice Bran Green Composite Using RSM and Design of Experiment Techniques

The aim of this research is to synthesise a cost-effective biodegradable green composite for various low- and medium-load applications. The tensile and flexural results reveal that the rice bran composition in green composite enhances the stiffness of composite, while strength and hardness decrease. The highest values of tensile strength 27 MPa and flexural strength 25 MPa were obtained for 15/85 treated rice bran composites, while the highest value of young modulus 2958 MPa was obtained for the 35/65 composite combination. The highest value of hardness, i.e., 11 HRF was obtained for 15/85 treated rice bran composite. The water absorption test reveals the hydrophilic nature of rice bran and the hydrophobic nature of PLA. Results also reveal better water-absorbing properties of the green composite due to the surface treatment of rice bran. The lowest density of 1.001 g/cm3 found for the 50/50 composite combination means the addition of rice bran makes the composite light in weight. The thermogravimetric analysis performed on the composite to analyse its thermal behaviour shows that major weight loss occurs approximately in the temperature range of 80–350° Celsius. The response surface methodology (RSM) and design of experiment (DOE) optimization model were developed to find that the optimum condition for maximum weight loss reveals two desirable conditions, i.e., 500° Celsius and 424.85° Celsius. ANOVA analysis reveals that the obtained results are significant.

PENGARUH POSISI SHIELDED METAL ARC WELDING (SMAW) GERAK SPIRAL KAMPUH V TERHADAP KEKUATAN TARIK DAN STRUKTUR MIKRO BAJA KARBON RENDAH

The purpose of this study was to determine the relationship between the position of shielded metal arc welding (SMAW) with spiral motion V on the tensile strength and microstructure of low carbon steel. The research was conducted by welding V-coated low carbon steel with horizontal 2G, vertical 3G and overhead 4G. The test results show that the welding position does not have a significant effect on the tensile strength of low carbon steel welds, where the 3G vertical position provides a higher tensile strength value than the 2G horizontal position and 4G overhead. The microstructure of acicular ferrite (AF) in the vertical position looks dominant uniformly and tightly.

INVESTIGATION OF THE INFLUENCE OF SPECIMEN MANUFACTURING PARAMETERS BY THE SELECTIVE LASER MELTING (SLP) METHOD AND COMPARATIVE STUDIES OF THE MECHANICAL PROPERTIES OF ALUMINUM ALLOY AlSi10Mg

Purpose. To work out the modes of manufacturing samples from aluminum alloy AlSi10Mg with a layer thickness of 40 microns using SLP technology, studying their mechanical properties, and comparing them with the traditional method of production.
 Research methods. To determine the structural state of alloys, optical microscopy was used, granulometric analysis was performed using a scanning electron microscope, mechanical properties were determined according to the standard method using a tearing machine; porosity was determined based on the results of microstructural analysis as a percentage of the area occupied by pores.
 Results. It was established that when the scanning speed is increased to 1200 mm/s, the distance between the tracks plays a significant role in obtaining high density. From the analysis of mechanical properties, it was established that the samples made by SLP technology have a higher value of tensile strength by 28%, and smaller plastic characteristics (relative elongation and relative reduction) by 17.4% and 31.7%, respectively, compared to the traditional production method.
 Scientific novelty. The dependence of the change in the density of the experimental samples made by the SLP technology with AlSi10Mg on the manufacturing parameters is shown. It was established that at a scanning speed of 1000...1100 mm/s, the pore size is on average from 2...7 μm and for samples made at a scanning speed of 1200 mm/s - from 1 to 5 μm.
 Practical value. Application of the obtained results will lead to the manufactured parts with increased strength characteristics.

Preparation and characterization of silicone rubber socket liners modified by nanoparticles additives

The upper part of the prosthesis is called a socket, which contacts the amputated part. While wearing the prosthesis, there are several problems that the patient may suffer from, such as shear force between the socket and amputated part, pressure on the bony prominences, sweating, and bacteria generation, all leading to skin problems and a bad smell. It makes the patient refuse to wear the prosthesis because it is uncomfortable. Therefore, the aim of this study was comfortable lining from silicone rubber which cross-links at room temperature, with properties corresponding to the needs of this application, such as stress distribution, moisture absorption, and antibacterial.In the current work, silicone rubber was selected with the addition of nano-fillers (ZnO, Mg(OH)2, and Chitosan). Mechanical and physical properties were studied (tensile strength, tear strength, hardness, water absorption, porosity, and antibacterial).Chitosan showed the highest effect on the mechanical properties of silicon, as it achieved the highest value of tensile strength of 2.2 MPa elongation of 572%, tear strength 13.9 kN/m, and shore A hardness of 33.3. While the highest value of the modulus, 0.636 MPa was achieved by adding ZnO. The results also showed an increase in the water absorption and the porosity, which were the highest values at 1.6 % and 0.24%, respectively with the addition of Mg(OH)2. The samples showed a clear resistance to preventing the microorganisms growth.Manufactured linings require additional improvement in mechanical properties by mixing more than one type of additives mentioned in the research. Thus, physical and biological properties can be obtained simultaneously with mechanical properties.The above results qualify the silicone rubber composites for use as a socket liner due to their flexibility and ability to absorb water in addition to their resistance and prevent the growth of fungi and bacteria.The method of preparation and properties of the lining material and additives qualify it for such applications as physical and biological properties.

Edible Film Biocomposite based on Cassava Starch/Soy Lecithin Reinforced by Sugarcane Bagasse Fiber: Mechanical, Morphological and Moisture Properties

Edible film biocomposite (EFB) is a kind of materials able to substitute the non-biodegradable plastics. This idea is one of the breakthroughs in reducing plastic waste which is not environmentally friendly. EFB is an environmentally-safe and biocompostable material. This research explores and fabricate EFB from tapioca starch, soy lecithin and sugarcane bagasse fiber (SBF). The SBF was varied by 1, 2, and 3% (from dry starch) into the cassava starch/soy lecithin matrix. The production of EFB was solution casting. A tensile machine and Scanning Electron Microscope (SEM) observed the tensile properties and fracture surface characteristics. The results present that the highest value of tensile strength is in EFB (2% SBF) of 0.823 MPa. The tensile modulus shows a similar trend in values for this EFB of 0.523 MPa. In addition, the fracture surface provides information that a rough surface indicates a good bond between the matrix and the fiber. These two observations confirm that the matrix has successfully transferred the tensile load to the reinforcement. Meanwhile, the results of resistance to moisture resistance also experienced an increasing trend of around 4% from unreinforced specimens.

MECHANICAL TEST AND THERMAL STABILITY ON THERMOPLASTIC SAGO (Metroxylon sagu Rottb.) COMBINATION OF POLYETHYLENE AND POLYPROPYLENE

Polyethylene is a polymer that has good elasticity properties, while polypropylene is a polymer with a high tensile strength value. Thus, the combination of these two polymers is expected to increase the value of tensile strength and elasticity. A biocomposite consisting of a mixture of Polyethylene-Polypropylene and thermoplastic sago starch (TPSS) was successfully prepared using the mixing method in an internal mixer. TPSS is made by reacting starch and glycerol with a composition of 65:35 wt.%. Compatibility was made by reacting Polyethylene-Polypropylene: Maleic anhydrate: Benzoyl peroxide with a composition of 88:9:3 wt. %. The match concentration used was 10wt.% based on the TPSS weight. The concentration of the Polyethylene-Polypropylene mixture starts from 0.10,15,20,25,30 and 100wt.%. The characterizations carried out are mechanical properties analysis are tensile strength, elongation at break and elasticity, FTIR analysis, and thermal properties are TGA and DTA. According to the test results, the addition of a mixture of polyethylene and polypropylene can increase the tensile strength from 1.7292MPa (without a mixture of polyethylene and polypropylene) to 4.8334MPa and the elongation at break also increases from 0.23% to 1.72% at a concentration of 30wt.%. Meanwhile, Young’s Modulus decreased from 740 to 281MPa at a concentration of 30 wt. %

EFFECT NICKEL AND QUENCH-TEMPER PROCESS ON MECHANICAL AND CORROSION PROPERTIES OF ASTM A588 WAETHERING STEEL

The mechanical improvement and "self-protection" properties are mainly needed to develop weather-resistant steel materials. In this study, A588 steel was given thermomechanical treatment (hot-rolling) followed by a quench-tempering process. The A588 is modified by adding 1, 2, and 3 wt% nickel to the primary alloy. Steel is made using a hot rolling process at 750 ℃ for 1 hour with 70% thickness reduction. The sample is heat-treated at 850 ℃ for 1 hour and quenched in water, oil, and open air. The tempering process is conducted at 400 ℃ for 30 minutes. Metallography test is confirmed final microstructural and compared with CCT simulation result. The fast cooling (water and oil quenchant) produces tempered martensite, ferrite, and pearlite, while the air-cooled forms a ferrite-pearlite. The cooling rate significantly affects strength and hardness and the nickel addition on hardness, and both factors have no significant on ductility. The sample owns the highest tensile strength value (~1226 MPa) with 1 %Ni, and the highest ductility value (around 17.1–27.43%) is obtained by air cooling. With 3% Ni, the corrosion rate decreases to 0072 mpy with -432.5 mV for corrosion potential and 0.12µA/cm-2 for current density.

The Effect of The Addition of Chitosan and Calcium Silicate on The Characteristic of Bioplastics from Corn Starch

Plastic waste in Indonesia has an impact that has caused high levels of environmental pollution. The use of plastic in everyday life as a packaging continues to increase, causing plastic waste to increase day by day. Plastic waste derived from petroleum raw materials is difficult to decompose by microbes in the soil. Biodegradable plastics are plastics that can be degraded by microorganisms and are made from renewable materials. Research on the use of biodegradable plastic synthesis has been developed because it is environmentally friendly and renewable. Biodegradable plastic is an alternative material to replace conventional plastic packaging so as not to pollute the environment. Biodegradable plastic is made with natural polymers as the main ingredient so that it is easily digested by microorganisms. Corn starch is a waste from corn processing used by the food industry. The starch content in corn starch can be used to make biodegradable plastic. In this study, biodegradable plastic was synthesized from corn starch with chitosan and calcium silicate as filler and then glycerol as a plasticizer. The purpose of this study was to determine the variation of filler on the results of biodegradable plastics made. The characteristics of biodegradable were marked by the presence of Tensile Strength, Elongation and Biodegradibility tests according to SNI Standards. The highest Tensile Strength value was obtained for the Chitosan variation of 2.62 Mpa and for the Calcium Silicate Variation of 2.8 Mpa, then for the Elongation Value for the Chitosan and Calcium Silicate Variations in accordance with SNI standards, which was 10-40% and for the Biodegradability of Chitosan and Calcium Silicate Variations. Calcium Silicate about 35-40 days.

Laju perambatan retak fatik dan sifat mekanik pada pengelasan friction stir welding (FSW) aluminium AA2024-T3 dengan perlakuan transient thermal tensioning (TTT)

One type of engineering material that is often used in transportation construction, especially for aircraft, automotive, ships, and other industries is aluminum alloy. Aluminum alloys have excellent mechanical properties, including corrosion resistance, lightweight, and good formability. However, in addition to these good properties, aluminum also has a weakness, namely the appearance of porosity and cracks when connected using arc welding (TIG, MIG). Friction stir welding (FSW) is an appropriate welding method for aluminum alloys to overcome these weaknesses, but the next problem will arise, namely related to distortion, decreased mechanical properties, and residual stress. For this reason, additional treatment is needed in order to improve the mechanical properties of the FSW welding results. The research method to be carried out is to carry out the FSW welding process on 2024 T3 aluminum alloys by adding moving local heat or transient thermal tensioning (TTT) using a heater placed in front of the tool and a heating temperature of 200°C. Some of the characterizations that will be carried out are microstructure tests, tensile tests, and fatigue tests. The results showed that the highest tensile strength value was obtained in the 1500 specimen, which was 312.2 MPa. The microstructure in the nugget zone (NZ) is fine-grain equiaxed. The lowest fatigue crack propagation rate at ΔK values of less than 7 MPa.m0.5 occurred in the 1100 specimen, while in other specimens the fatigue crack propagation rate was higher.

The Effect of Montmorillonites on the Physicochemical Properties of Potato Starch Films Plasticized with Deep Eutectic Solvent.

In the paper, the method of obtaining the potato starch nanocomposites plasticized with a deep eutectic solvent is described. The deep eutectic solvent based on choline chloride and malic acid (CM, molar ratio 1:1) was used as the plasticizer. The effect of the sodium and calcium montmorillonite (MMTNa, MMTCa respectively) addition on the properties of potato starch films was investigated. The thermal, mechanical, and barrier properties were determined. Moreover, a moisture absorption test was performed. The starch gelatinization temperature increased in the presence of montmorillonite. The values of glass transition determined by DMTA depended on the nanofiller type. For the systems containing MMTCa, they generally decreased with its content (although still lower than reference samples). The obtained nanocomposites showed improved mechanical and barrier properties. The highest values of tensile strength and Young's modulus were noted for the system containing 1% MMTNa. The XRD revealed that only the films with MMTNa exhibited intercalation. The homogeneity of the samples decreased with increasing nanofiller concentration. This was probably due to the occurrence of choline chloride-montmorillonite interactions, which were more favored than clay-starch interactions.

New polyurethanes containing cycloaliphatic units in the hard segments. The influence of the microstructure on the thermo‐mechanical and surface properties

AbstractNew linear and cross‐linked polyurethanes with cycloaliphatic units and renewable cross‐linkers (Span 20 and Tween 20) were obtained by two steps polyaddition reaction. The degree of microphase separation was calculated by FTIR‐ATR spectroscopy with higher values for the linear polyurethane with the highest hard segment content (0.88) and lower values for the cross‐linked polyurethane with Tween 20 as cross‐linker (0.35). The results were in accordance with the DSC analysis. The linear or cross‐linked character of the polyurethane structure influenced the thermal, mechanical, and surface properties. The obtained polyurethanes had good thermal stability, with a 5% mass loss at 321°C (HMC 1) and 329°C (HMC 2) for linear polyurethanes and 330°C (HMC 3) and 342°C (HMC 4) for the cross‐linked ones. The morphology and wettability of the cycloaliphatic polyurethanes presented different behavior depending on the amount of the hard segment content and also the chemical structure of the cross‐linker. Linear polyurethanes were characterized by a globular morphology and hydrophobic character, while the use of Tween 20 as cross‐linker led to a fibrillar morphology with a low water contact angle (62°). Mechanical measurements showed that all polyurethanes present elastomeric behavior with high tensile strength values for the linear polyurethanes (33 MPa for HMC 1 and 39 MPa for HMC 2) and lower values of tensile strength for the cross‐linked ones (12 MPa for HMC 3 and 11 MPa for HMC 4), but high elongation at break for all samples (780%–1100%).

EFFECT OF SILANIZED TITANIUM DIOXIDE ON TENSILE STRENGTH OF SELF-CURED ACRYLIC RESIN

Background: Self-curing acrylic resin is a material used to make artificial tooth bases as well as reparate it when there is a fracture on the tooth bases. Titanium dioxide is one of the metal oxides that can be added to acrylic resins as an addition materials. This study aims to determine the effect of adding silanized titanium dioxide filler (TiO2) on tensile strength of self-cured acrylic resin. Methods: This study is a true experimental laboratory study with the design post test only group design, using self-cured acrylic resin plates amounting to 24 plates measuring 165mm x 13mm x 3mm divided into groups of 4 with adding and without adding silanized TiO2. The self-cured acrylic resin plate mixed with silanized TiO2 was tested for tensile strength with a Universal Testing Machine. The data obtained were analyzed with Kruskal-Wallis test. Results: There is an effect of adding titanium dioxide filler (TiO2) to the tensile strengthof self-cured acrylic resin with the highest tensile strength value at 26,1327 MPa ± 2,29608. Conclusion: 5% titanium dioxide filler showed the highest tensile strength than other groups.

Multi Regression Model for Cutting Force During Dry Turning of Duplex Stainless Steels Using Definitive Screening Design

Considering the current trend in environmentally friendly machining or dry machining, it is observed that it’s adverse effect on various surface integrity aspects is usually not covered adequately in the literature. This adverse effect leads to untimely in-service failure of components subjected to fatigue loads. This research work has advocated the use of dry machining with consideration on minimizing its adverse effects by selecting appropriate machining parameters for Duplex Stainless Steel (DSS). These materials pose various challenges during secondary processing operations, like machining, due to lower values of thermal conductivity, higher values of tensile strength, toughness, work hardenability & tendency for built-up edge formation. In such applications, higher values of cutting forces are generated, and efforts are required to minimize them in order to reduce the carbon footprint. A multiple regression model for cutting force, during turning of DSS was generated as part of the study, based on experiments conducted using Definitive Screening Design (DSD). Four process parameters, viz. cutting speed, tool feeding rate, depth per pass and radius of curvature of tool nose were varied at three different values independently and their effect on main cutting force was observed. The multiple regression model generated using the stepwise procedure has coefficient of determination (R2) of 99.7 %. Cutting depth followed by rate of feeding and radius of curvature of tool nose were found to be influential parameters in the model. Minimization of force by desirability optimization method was further carried out. This resulted in minimum value of force as 128.6 N. For this, cutting speed of 120 m/min, feed rate of 0.1 mm/rev, depth per pass of 0.5 mm and tool nose curvature radius of 1.6 mm should be selected. The composite desirability score for these optimum settings was 98.79 %.

The Effect of Beeswax and Glycerol Addition on the Performance of Bioplastic Film Made of Konjac Glucomannan

In this study, bioplastics made of Konjac glucomannan have been successfully prepared via film casting method. The effects of addition of beeswax content (i.e. of 0%, 0.5%, and 1%,), as well as glycerol content (i.e. 0.5%, 1%, and 1.5%) on the properties of the bioplastics have been investigated. The bioplastics produced have been characterized for their tensile strength, percent elongation, swelling degree, and biodegradability. The results of this study, showed that most of the bioplastic samples have weight loss of about 95% after the drying process as well as the finished film. The addition of beeswax and glycerol concentrations also increased tensile strength and percent elongation of the bioplastics. The highest value of tensile strength occurred at bioplastic film with a concentration of 1.5% beeswax and 1% glycerol (i.e. Sample C3) with a value of approximately 3.5 MPa. Whereas, the highest percent elongation value occurred at bioplastic film with a concentration of 1.5% beeswax and 1% glycerol (i.e. Sample C3) with a value of approximately 23.29%. These tensile and percent elongation values were higher or comparable to other bioplastic samples made from starch of different raw materials reported by literatures. In the other hand, the addition of beeswax and glycerol decreased the degree of swelling. The degree of swelling for all the bioplastic film samples were in the range of 316.77 – 481%.

Industrial cutting waste granite dust reinforced cardanol benzoxazine/epoxy resin hybrid composites for high‐voltage electrical insulation applications

AbstractAn attempt has been made to develop hybrid composites from benzoxazine monomer (C‐ddm) hybridized with DGEBA epoxy resin (EP) and reinforced with varying weight percentages (20 wt%, 40 wt%, 60 wt%, 80 wt% and 100 wt%) of glycidoxypropyltrimethoxy‐ silane (GPTMS) functionalized granite dust (GD) obtained from industrial granite cutting and polishing process in order to utilize them for electrical insulation applications. The thermal stability of granite dust reinforced poly(EP‐co‐C‐ddm) composites was studied by TGA analysis. Among the composites samples studied, 100 wt% GD reinforced poly(EP‐co‐C‐ddm) composites possess better thermal stability than that of other neat matrices and composites. Among the composites prepared using varying weight percentages of functionalized GD reinforcement, it was observed that 80 wt% GD reinforced poly(EP‐co‐C‐ddm) composites possesses better hydrophobic character than that of other neat matrices and composites. The value of LOI calculated for neat matrix (poly[EP‐co‐C‐ddm]) and 20 wt%, 40 wt%, 60 wt%, 80 wt% and 100 wt% GD reinforced composites was found to be 22, 28, 34, 40, 43 and 45 respectively. The 80 wt% GD reinforced poly(EP‐co‐C‐ddm) composites possess the higher values of tensile strength and flexural strength of 47 MPa and 140 MPa, respectively than those of their samples. The values of electrical surface resistivity and electrical volume resistivity of all the neat matrices and GD reinforced polybenzoxazine composites were found to be in the order of 1012 and 1013 respectively. The values of dielectric strength obtained from break down voltage (BDV) for neat matrix [poly(EP‐co‐C‐ddm)] and 20 wt%, 40 wt%, 60 wt%, 80 wt% and 100 wt% of GD reinforced poly(EP‐co‐C‐ddm) composites are 15.0, 15.5, 16.5, 17.0, 17.0 and 17.0 kV/mm, respectively. Data obtained from thermal stability, hydrophobic behavior and dielectric studies it was inferred that the hybrid polymer composites developed in the present work can be conveniently used in the form insulators, sealants, adhesives and matrices where application demands at high‐performance industrial and engineering applications.

Gelatin/monetite electrospun scaffolds to regenerate bone tissue: Fabrication, characterization, and in-vitro evaluation

This work is dedicated to combining nanotechnology with bone tissue engineering to prepare and characterize electrospun gelatin/monetite nanofibrous scaffold with improved physicochemical, mechanical, and biological properties. Nanofibrous scaffolds possessing fiber diameter in the range of 242–290 nm were prepared after incorporating varying content of monetite nanoparticles up to 7 wt % into the gelatin matrix using the electrospinning technique. Cross-linking of gelatin chains in the scaffold was performed using 0.25 wt% glutaraldehyde as indicated by imine (-CN-) bond formation in the FTIR analysis. With an increase in monetite addition up to 7 wt%, a decrease in swelling ratio and bio-degradability of cross-linked gelatin scaffolds was observed. Gelatin scaffold with 7 wt% monetite content registered the highest values of tensile strength and tensile modulus of 18.8 MPa and 170 MPa, as compared to 0% and 5 wt% monetite containing scaffolds respectively. Cell viability and differentiation were studied after culturing MG-63 cells onto the scaffolds from confocal microscopy of live and dead cells images, MTT assay, and alkaline phosphatase assay for a cell culture period of up to 21 days. It was observed that 7 wt % monetite containing gelatin scaffold exhibited better MG-63 cell adhesion, proliferation, higher biomineralization, and ALP activity compared to 0% and 5 wt% monetite containing electrospun scaffolds studied here.

Güçlendirilmiş Polyester Reçine Matrisli Kompozit Malzemelerin Tek Yönlü Karbon Fiberler Üzerinde Katmanların Etkisi

In this study, composite materials are produced, placing unidirectional carbon fiber reinforcements with 12 filament numbers in a polyester matrix to form one, two, and three layers at room temperature through the hand lay-up method. The samples are prepared from composite plates with the help of a mold in line with the fiber direction angle by the standards. The tensile, three-point bending, and falling weight low-speed impact strength values of the samples were measured and were investigated the mechanical performance of the specimens. As a result of the tensile test, the highest tensile strength value among layers is obtained in the two-layer unidirectional fiber-reinforced composite materials. In bending tests, the highest elasticity values of unidirectional carbon fiber reinforcements are observed in three-layer composite materials with a fiber direction angle of 00. 00 unidirectional fiber-reinforced one-layer composite materials are observed in composite materials with the highest deformation values in the falling weight low-velocity impact tests.

Does Knot Configuration Improve Tensile Characteristics of Monofilament Suture Materials?

The effects of knot configuration used in surgical procedures are often overlooked when surgeons are looking for an ideal suture material. This study aimed to investigate the mechanical properties of monofilament suture materials used in oral and maxillofacial surgery under diverse knot configurations. A custom-made experimental platform and a microtensile test device were used to evaluate the mechanical properties of the tested subjects. There were 2 predictor variables: suture material and knot configuration. Three types of nonabsorbable and monofilament suture materials with 4-0 gauge, including nylon, polypropylene, and polytetrafluoroethylene, were tested. Four different knot configurations-a surgeon's knot square plus a square knot (2=1=1), a surgeon's knot granny plus a square knot (2×1=1), a reverse surgeon's knot granny plus a square knot (1×2=1), and a reverse surgeon's knot square plus a square knot (1=2=1)-were also used with each of the suture materials. The tensile strength (N) and elongation (μm) of each sample were measured as the outcomes. The data were statistically analyzed using 2-way analysis of variance and Tukey's honestly significant difference tests. The significance level was set at P<.05. Overall, 120 samples were tested. Statistical analysis revealed that the highest tensile strength (28.6N) was found for nylon in the surgeon's knot square plus a square knot (P<.05). Polypropylene showed a similar high tensile strength value (24.7N) in the reverse surgeon's knot granny plus a square knot (P>.05). Polytetrafluoroethylene demonstrated significantly lower values for both tensile strength in tested configurations (within the range of 5.2-8.5N). Under diverse configurations, polypropylene suture samples offered the most stable tensile strength and elongation. The present study demonstrated that different knot configurations might improve the mechanical profile of commonly used monofilament suture materials. The surgeon's knot square (2=1), commonly used by surgeons worldwide, proved to be the most beneficial knot configuration in this study in terms of tensile strength and elongation. Further research on optimal knot configuration may be just as important as seeking an ideal suture material.

Development and mechanical characterization of LM6/Al2O3/SiC/Graphite metal matrix composites using stir casting

ABSTRACT In the present study, three reinforcements viz. graphite, SiC and Al2O3 were added in LM6 matrix to evaluate their strengthening efficiency. Stir casting technique was utilised for fabrication of composites, where the amount of reinforcements varied from 1.0 wt.% to 3.0 wt.%. Hardness and tensile strength was performed to evaluate the mechanical properties and optical microscopy was utilised to analyse the microstructure of the prepared composites. It was observed that the tensile strength and hardness increased linearly, irrespective of the reinforcement type and content. However, graphite reinforced composites exhibited best mechanical properties followed by SiC and Al2O3 reinforced composites. From the optical microscopy images, it was clearly observed that as the concentration of reinforcement increased, the tendency to form agglomerates also increased eventually resulting in porosities. However, composites containing large amount of reinforcements still displayed highest values of tensile strength and hardness. This might be attributed to the fact that the detrimental effect of porosities was negligible as compared to the strengthening effect exerted by the reinforcements.

Pengaruh variasi bevel pada proses pengelasan SMAW terhadap kekuatan tarik material

The strength of welded joints is influenced by a wide variety of factors. One of them is due to structural changes as a result of the heating process. In order for the connection between the two metal parts to have good quality, it is necessary to have a proper welding and the connection and the shape of the weld bevel are in accordance with the use of the results of the weld. Parameters in Shielded Metal Arc Welding (SMAW) welding include current strength, voltage, electrical polarity, and the angle of the joint used. These parameters make the basis for the right selection in order to get a good quality or connection quality. The purpose of this study was to determine the effect of bevel variations on the tensile strength test of the SMAW welding process connection on medium carbon steel material. The welding process is carried out using RB 26 type electrodes using a current of 100 A at 1 G welding position, welding is carried out on the material using V, I and double V bevel with 1 specimen per bevel. Based on the research that has been done, it can be concluded that the type of joint bevel has an important influence on the results of the weld. From the variation of the bevel that has the highest tensile strength value, it is V bevel rather than double V bevel and 1 bevel. Due to the variation of V bevel has a small distortion angle compared to double V bevel and I bevel. Optimal electric welding results depend on the welding process technique.