Multicomponent formulations coupled with complex processing conditions govern the final properties of photopolymerizable dental composites. In this study, a single test substrate was fabricated to support multiple formulations with a gradient in degree of conversion (DC), allowing the evaluation of multiple processing conditions and formulations on one specimen. Mechanical properties and damage...

chewable ferrous fumarate tablet is the best iron dosage form for children due to better compliance and lower teeth staining compared to the oral drop. because of the different desirable properties of chewable tablets and the opposing effects of fillers on them, the mathematical experimental design was used as the formulation approach. different series of formulations based on single filler (la...

Nanomechanical properties of indium nanowires like structures fabricated on quartz substrate by trench template technique, measured using nanoindentation. The hardness and elastic modulus of wires were measured and compared with the values of indium thin film. Displacement burst observed while indenting the nanowire. 'Wire-only hardness' obtained using Korsunsky model from composite hardness. N...

This lecture is about hardness and computational problems that seem hard. Almost all of the theory of hardness is based on assumptions. We make assumptions about some problems, then we do reductions from one problem to another. Then, we want to make the minimal number of assumptions necessary to show computational hardness. In fact, all work on computational complexity and hardness is essential...

We investigate a variant of the so-called Internet Shopping problem introduced by Blazewicz et al. (2010), where a customer wants to buy a list of products at the lowest possible total cost from shops which offer discounts when purchases exceed a certain threshold. Although the problem is NP-hard, we provide exact algorithms for several cases, e.g. when each shop sells only two items, and an FP...

Abs t r ac t . For any fixed parameter t _> 1, a t-spanner of a graph G is a spanning subgraph in which the distance between every pair of vertices is at most t times their distance in G. A minimum t-spanner is a t-spanner with minimum total edge weight or, in unweighted graphs, minimum number of edges. In this paper, we prove the AlP-hardness of finding minimum t-spanners for planar weighted g...

Hardness is too complex to be described by first principles. Based on the dielectric chemical bond theory, a semiempirical approach for the evaluation of the hardness of ionic oxide crystals has been proposed. It was applied to predict the hardness of complex crystals such as the optical crystals yttrium aluminum garnet, the LaMgAl11O19 aluminates, and the high-Tc superconductor YBa2Cu3O7. The ...

Mechanical hardness testing is fundamental in the evaluation of the mechanical properties of metallic materials due to the fact that the hardness values allow one to determine the wear resistance of the material involved, as well as the approximate values of its ductility, flow tension, among a number of other key characteristics. As a result, the main objective of the present work has been the...

The shear strength plays an important role in avalanche formation. However, investigations on shear strength in the field are time-consuming, in particular these measurements require experienced avalanche professionals. Main objective of this study was to estimate shear strength by using indirect methods which are more user-friendly than the traditional tests. We assumed that hardness and densi...

objectives: the aim of this study was to compare polymerization depth of two bulk-fill and one conventional composite cured for different times. methods: this in vitro experimental study was conducted on 54 composite samples (2×4×10mm) fabricated of tetric n-ceram bulk-fill, x-tra fil bulk-fill, and grandio conventional composite cured for 20, 30, and 40 seconds. the microhardness of samples wa...