Kekuatan Mekanis Antibacterial Resin Campuran Titanium Dioksida

<p class="Abstract">The aim of this research is to analyze the effect of Titanium Dioxide (TiO2) nanoparticles as resin concentrate on mechanical strength. The tested mechanical strength is Bending strength, Impact Strength, and Microhardenest Strength. The types of resin used in this study were acrylic resin without conventional modification and acrylic resin with an additional 0.01 gr and 0.06 gr of TiO2. Specimen dimensions are made revered to ISO 20795-1 (2008) standard specifications. Mechanical strength was determined by using the universal testing machine, Izod pendulum impact testing machine, and also Vickers microhardness tester. From the analysis, the researcher found that the bending strength of resin acrylic was greatly decreased by increasing the TiO2 concentration. It happens in both TiO2 0.01gr and 0.06gr of acrylic resin compared to the non TiO2 resin. The impact strength of 0.01gr TiO2 acrylic resin was significantly increased compared to non TiO2 acrylic resin. But on the other hand for 0.06gr acrylic resin, impact strength was decreased and recorded the lowest impact strength. The highest Micro hardness strength was found in 0.06gr TiO2, It is significantly increased compared to 0.01gr TiO2 and 0gr TiO2. The general conclusion is, adding 0.01gr TiO2 nanoparticles as concentrated into acrylic resin can significantly increase the bending strength, bending strength, and microhardness strength. Meanwhile, adding 0.06gr Tio2 nanoparticles as concentrated into acrylic resin can only increase the bending strength and the microhardness strength, but not for its impact strength.</p>

Effect of span length on the impact bending strength of poplar and pine woods

Solid wood is an important engineering material. Solid wood has superior properties, such as being renewable, easily processed, relatively inexpensive, and having higher mechanical properties relative to its density than any other engineering materials. Density, moisture content, tree species, knots, cracks, and some other variables influence the mechanical properties of wood. In this study, the effect of span length on the impact bending strength (IBS) of wood was investigated. Poplar and pine wood samples were used as test materials in the experiments. The IBS measurements were carried out following TS 2477 (1976) using a pendulum impact bending machine. Tests were conducted for various span lengths of 10, 15, 20, 25, 30, and 35 cm. The results indicated that there is a relationship between IBS and span length. The highest impact bending strength was obtained with a span length of 10 cm for poplar and pine wood. The relationship between IBS and span length was parabolic. The coefficients of determination were 0.94 and 0.99 for poplar and pine wood, respectively.

Effect of Welding Heat Input on Simulated HAZ Areas in S960QL High Strength Steel

When the weldability of high strength steels is analyzed, it is the softening in the heat-affected zone (HAZ) that is mostly investigated, and the reduction of toughness properties is generally less considered. The outstanding toughness properties of quenched and tempered high strength steels cannot be adequately preserved during the welding due to the unfavorable microstructural changes in the HAZ. Relevant technological variants (t8/5 = 2.5–100 s) for arc welding technologies were applied during the HAZ simulation of S960QL steel (EN 10025-6) in a Gleeble 3500 physical simulator, and the effect of cooling time on the critical HAZ areas of single and multipass welded joints was analyzed. Thermal cycles were determined according to the Rykalin 3D model. The properties of the selected coarse-grained (CGHAZ), intercritical (ICHAZ) and intercritically reheated coarse-grained (ICCGHAZ) zones were investigated by scanning electron microscope, macro and micro hardness tests and instrumented Charpy V-notch pendulum impact tests. The examined HAZ subzones indicated higher sensitivity to the welding heat input compared to conventional structural steels. Due to the observed brittle behavior of all subzones in the whole t8/5 range, the possible lowest welding heat input should be applied in order to minimize the volume of HAZ that does not put fulfillment of the allowed maximal (450 HV10) hardness at risk and does not lead to the formation of cold cracks.

Effect of Three-Dimensional Printing With Nanotubes on Impact and Fatigue Resistance

The types of biomedical devices that can be three-dimensional printed (3DP) are limited by the mechanical properties of the resulting materials. As a result, much research has been focused on adding carbon nanotubes (CNT) to these photocurable polymers to make them stronger. The objective of this study was to expand the use of 3DP to prosthetics by testing the hypothesis that adding CNTs to a stereolithographic (SLA) photocurable resin will result in a cured polymer with increased impact and fatigue resistance. For impact testing, twenty-six total specimens, 13 with nanotubes and 13 without nanotubes, were printed on a Form2 SLA printer. Once all the specimens were printed, washed, and cured, the impact resistance was quantified using a pendulum impact tester using a notched Izod configuration. Similarly, twelve R. R. Moore fatigue specimens were printed, washed, and cured. The specimens with SWCNTs (0.312 ± 0.036 ft lb/in.) had a significantly lower impact resistance compared to the non-SWCNT specimens (0.364 ± 0.055 ft lb/in.), U = 34.0, p = 0.004. Adding SWCNTs also reduced the short cycle fatigue life (i.e., 103) from 3.1 × 5 to 8.8 × 3 psi and increased the endurance limit from 0.4 to 3.0 × 3 psi. If used for creating a foot prosthetic, the non-SWCNT polymer would last 2919 cycles while the SWCNT mixture would last <1 cycle. Therefore, SLA polymers do not yet have the impact and fatigue resistance capabilities to be used for prosthetic feet.