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In this paper, the applicability of mechanical tests for biomass pellet characterisation was investigated. Pellet durability, quasi-static (low strain rate), and dynamic (high strain rate) mechanical tests were applied to mixed wood, eucalyptus, sunflower, miscanthus, and steam exploded and microwaved pellets, and compared to their Hardgrove Grindability Index (HGI), and milling energies for knife and ring-roller mills. The dynamic mechanical response of biomass pellets was obtained using a novel application of the Split Hopkinson pressure bar. Similar mechanical properties were obtained for all pellets, apart from steam-exploded pellets, which were significantly higher. The quasi-static rigidity (Young’s modulus) was highest in the axial orientation and lowest in flexure. The dynamic mechanical strength and rigidity were highest in the diametral orientation. Pellet strength was found to be greater at high strain rates. The diametral Young’s Modulus was virtually identical at low and high strain rates for eucalyptus, mixed wood, sunflower, and microwave pellets, while the axial Young’s Modulus was lower at high strain rates. Correlations were derived between the milling energy in knife and ring roller mills for pellet durability, and quasi-static and dynamic pellet strength. Pellet durability and diametral quasi-static strain was correlated with HGI. In summary, pellet durability and mechanical tests at low and high strain rates can provide an indication of how a pellet will break down in a mill.

Background This in vitro study compared the stability of different fixation method combinations for the zygomatic complex after simulated L-shaped osteotomy reduction malarplasty, a common facial contouring surgery in East Asia with high postoperative complications due to poor fixation methods. Materials and Methods The study used 108 zygoma replicas with various fixation methods combinations in the zygomatic body (L-shaped plate with short wing on zygoma and on the maxilla, two bicortical screws, one bicortical screw with L-shaped plate, square plate, and rectangular plate) and zygomatic arch (Mortise–Tenon structure, 3-hole plate, and Mortise–Tenon structure plus short screw). The failure force under incremental load was applied through the Instron tensile machine to a well-stabilized model using a rubber band simulating the masseter muscle and recorded the increasing force digitally. ANOVA test was used for comparison between recorded values ( P < 0.05). Results The results showed that the most stable combination was a six-hole rectangular plate and a Mortise–Tenon structure plus one short screw (358.55 ± 51.64 N/mm2). The results also indicated that the placement vector of the fixation methods around the L-shaped osteotomy and the use of the two-bridge fixation method were important factors in enhancing the stability of the zygomatic complex. Conclusion The study suggested that surgeons should choose appropriate fixation methods based on these factors to reduce postoperative complications and improve surgical outcomes. No Level Assigned This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Magnetic polyurethane elastomer nanocomposites were prepared by incorporating pure and thiodiglycolic acid (TDGA) surface-modified Fe 3 O 4 nanoparticles into polyurethane matrix using in situ polymerization method. Surface modification of Fe 3 O 4 nanoparticles was carried out to enhance the dispersion of the nanoparticles in polyurethane matrix. Pure and TDGA surface-modified Fe 3 O 4 nanoparticles were synthesized by coprecipitation method and characterized by Fourier Transform Infrared Spectroscopy, X-ray diffraction, and Vibrating Sample Magnetometer. The morphology and dispersion of the nanoparticles in the magnetic polyurethane elastomer nanocomposites were studied by Scanning Electron Microscope. It was observed that surface modification of Fe 3 O 4 nanoparticles with TDGA enhanced the dispersion of the nanoparticles in polyurethane matrices. Furthermore, effect of surface modification of Fe 3 O 4 nanoparticles on thermal and mechanical properties of magnetic polyurethane elastomer nanocomposite was investigated by thermogravimetric analysis, dynamic mechanical thermal analysis, and an Instron type Tensile Tester. It was concluded that surface modification of Fe 3 O 4 nanoparticles allowed preparation of the magnetic nanocomposites with better mechanical properties. Moreover, study of fibroblast cells interaction with magnetic nanocomposites showed that the products can be a good candidate for biomedical application due to their in vitro biocompatibility and non-toxicity.

In this study, we evaluated the fracture resistance of three commercially available prefabricated primary zirconia crowns and their correlation with dimensional variance. Methods: a total of 42 zirconia crowns were selected from three companies, (1) NuSmile primary zirconia crowns, (2) Cheng Crowns zirconia, and (3) Sprig EZ crowns. The crowns were divided into two groups based on their location in the oral cavity and further divided into subgroups based on the brand. All of the samples were subjected to fracture tests using a universal testing machine. Results: the mean load observed was highest with Cheng Crowns zirconia anterior crowns (1355 ± 484) and the least load was seen with Sprig EZ anterior crowns with a mean load of 339 ± 94. The mean load observed was highest with Cheng Crowns zirconia posterior crowns (1990 ± 485) followed by NuSmile posterior crowns and the least load was seen with Sprig EZ posterior crowns with a mean load of 661 ± 184. Conclusion: the Cheng crowns showed the highest fracture resistance amongst all three groups. Overall, the zirconia crowns (anterior and posterior) tested showed optimum mechanical properties to withstand the masticatory forces.

Addition of filler to polylactic acid (PLA) may affect its crystallization behavior and mechanical properties. The effects of talc and hydroxyapatite (HA) on the thermal and mechanical properties of two types of PLA (one amorphous and one semicrystalline) have been investigated. The composites were prepared by melt blending followed by injection molding. The molecular weight, morphology, mechanical properties, and thermal properties have been characterized by gel permeation chromatography (GPC), scanning electron microscope (SEM), instron tensile tester, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). It was found that the melting blending led to homogeneous distribution of the inorganic filler within the PLA matrix but decreased the molecular weight of PLA. Regarding the filler, addition of talc increased the crystallinity of PLA, but HA decreased the crystallinity of PLA. The tensile strength of the composites depended on the crystallinity of PLA and the interfacial properties between PLA and the filler, but both talc and HA filler increased the toughness of PLA.

Delamination of polymer composite is one of the major failure characteristic, in this context the fracture behavior of the tailored composites in combination of opening mode and shearing mode is assessed and its fracture robustness of the glass fiber reinforced laminate are determined experimentally, in this present work by developing a modified Arcan fixture using a single edge notched specimen for characterizing in various loading conditions, The fixture was made of industrial grade Aluminum ingot machined to an outer diameter of 150 mm, having a thickness of 10 mm. The fixture had provision to load the sample at different oblique angles up to 90 degrees in steps of 15 degrees. The samples were attached to the fixture by means of fasteners and were tested in tensile mode using a 40 KN Instron tensile tester at constant displacement and ambient conditions. Further, the resin was strengthened with Carboxyl Terminated Butadiene Arenonitrile (CTBN) and its effect on fracture parameters was studied by varying the loading angles. Results indicate that the fracture parameters vary with loading and at angles greater than 45 degrees, the GFRP sample’s behavior changes from opening mode to shearing mode and the converse is also true. This pattern is similar, with the specimens even after modifying the resin with CTBN however, it was found that stress intensity factor increased corresponding to the increase of CTBN infusion. CTBN was dispersed into the Bisphenol base A (LY566– A general purpose thermoset epoxy resin) in three different percent: 1%, 3% and 5% by weight. The layup sequence used in this work was cross ply. The effect of varying the loading angles on the stress intensity factors were studied.

Currently, for the development of industry, it is very important and relevant to create materials with improved properties and parameters. The creation of composite materials based on polymers is promising.YBa2Cu3O6+x (YBCO) particles, according to the Le Chatelier principle, absorb oxygen atoms from the surrounding macromolecules of the matrix, causing a decrease in the volume of the polymer. The effect of nanodisperse fillers from YBa2Cu3O6+x in polyimide composite films on the interactions between macromolecules of the polymer matrix is considered. It was found that the introduction of nanodisperse fillers from YBa2Cu3O6+x in the composite material leads to an increase in the boundary layer due to the breaking of the bonds of polyimide macromolecules and the formation of free radicals that actively interact with YBCO crystals.

Aim: The aim of this study was to evaluate the kinetic frictional properties of colored titanium molybdenum alloy (TMA) archwires (purple-coated TMA and honey dew-coated TMA) and the regular TMA archwires. Materials and Methods: The experiment comprised of three groups, Group I - Regular TMA archwires, Group II - Purple-coated TMA archwires, Group III - Honey dew-coated TMA wires involving 21 samples each that were evaluated for their frictional properties using Instron Universal Testing Machine. Results: The results were subjected to statistical analysis using analysis of variance wherein Group I Regular TMA wires revealed mean kinetic frictional value of 8.236 N and a standard deviation of 0.4038 N, while Group II (purple-coated TMA wires) showed a mean value of 5.297 N, standard deviation of 0.3128 N and Group III (honey dew-coated TMA wires) showed a mean value of 4.206 N and a standard deviation of 0.5353 N. Conclusion: The kinetic frictional values are higher for regular TMA wire exhibiting superior characteristic of color-coated TMA. Wires exhibiting superior characteristics are color-coated TMA wires, especially honey dew-coated TMA wires over the regular and purple-coated TMA wires. These superior properties of newly introduced wires can be considered for its application in both details friction and frictionless mechanics in retraction phase of fixed orthodontic treatment.

Aims and Objectives: This study aimed to evaluate the effects of at-home and in-office bleaching on the shear bond strength (SBS) of metal, ceramic, and composite orthodontic brackets and to compare their SBSs. Subjects and Methods: A total of 96 human lower premolar teeth were used for this study. Six teeth were used for scanning electron microscopic study while the remaining ninety were divided into three equal groups. Each group was further subdivided into three subgroups with ten samples each. Three protocols were used. In the at-home bleaching group (n = 30), opalescence non-PF (potassium nitrate and fluoride) bleaching agent (10% carbamide peroxide) was applied onto the teeth daily for 14 days and left for 8 h each day. Teeth in the in-office group (n = 30) were treated twice in consecutive days with Opalescence boost PF (40% hydrogen peroxide). After bleaching, the specimens were stored in distilled water for 1 day before bonding. SBS testing was performed on all teeth using Instron universal testing machine. Results: Analysis of variance indicated a significant difference (P < 0.005) among the groups. Maximum SBS was shown by ceramic brackets in control group (Ib) and minimum was shown by composite brackets of in-office bleached group (IIIc). Conclusions: The results showed that at-home bleaching did not affect the SBS significantly whereas in-office bleaching reduced SBS of metal, ceramic, and composite brackets significantly. It is preferable to use metal or ceramic brackets than composite brackets for bonding 24 h after bleaching.

Because of its high-intensity light waves, it is claimed to cure adhesive materials in 1 or 3 seconds. Bond failures of brackets can significantly increase chair-side time, treatment time, and efficiency. [...]much effort has been put into improving the quality of the adhesive systems for direct bonding. First the mesial side was cured for 20 sec and the distal side was cured for 20 sec. First the mesial side was cured for 20 sec and the distal side was cured for 20 sec. The overall bond strength and mean value for Greegloo was slightly higher than Transbond XT. [...]grengloo can be used as an ideal orthodontic adhesive in terms of increase shear bond strength, quick cure polymerization, quick cure intiator provides faster cure, two- way color changing properties during bonding and deboing saves chair time, as analyzed in this study.