Bi-antibiotic-impregnated bone cements (BIBCs) are widely used in orthopaedics as a prophylactic agent (depot) to address post-surgical infections. Although hardness is widely considered a viable index to measure the integrity of the cement structure, there are few specific studies involving changes in hardness characteristics of BIBCs post elution of high doses of two widely used antibiotics: ...

In this research the constrained groove pressing (CGP) process as a severe plastic deformation (SPD) method was applied on commercially pure aluminum plates. According to the principle of CGP, a material is subjected to repetitive shear deformation by utilizing asymmetrically grooved dies and flat dies which are constrained by a channel. Each complete groove pressing pass consists of four press...

We show that several online combinatorial optimization problems that admit efficient no-regret algorithms become computationally hard in the sleeping setting where a subset of actions becomes unavailable in each round. Specifically, we show that the sleeping versions of these problems are at least as hard as PAC learning DNF expressions, a long standing open problem. We show hardness for the sl...

We systematically study the hardness and the approximability of combinatorial multiobjective NP optimization problems (multi-objective problems, for short). We define solution notions that precisely capture the typical algorithmic tasks in multiobjective optimization. These notions inherit polynomial-time Turing reducibility from multivalued functions, which allows us to compare the solution no...

– We define approximative solution notions and investigate in which cases polynomial-time solvability translates from one to another notion. Moreover, for problems where all objectives have to be minimized, approximability results translate from single-objective to multiobjective optimization such that the relative error degrades only by a constant factor. Such translations are not possible for...

We present some of the recent results on computational complexity of approximating bounded degree combinatorial optimization problems. In particular, we present the best up to now known explicit nonapproximability bounds on the very small degree optimization problems which are of particular importance on the intermediate stages of proving approximation hardness of some other generic optimizatio...

  Friction-stir welding process is a novel method of solid state welding, which produces heat due to friction between the pin, the shoulder and the workpiece. This heat causes a paste area. Shoulder pressure and pin spin cause edges integration and lead to welding. In this study, firstly, the feasibility of welding of steel sheet (EN10130) with a thickness of 1.5mm has been tested by 58 experim...

AIM To evaluate the effect of successive cycles of disinfection in different denture cleansers on the surface roughness and the Vickers hardness of two layers of acrylic resin (base-BL and enamel-EL) of two commercial cross-linked artificial teeth. MATERIALS AND METHODS The occlusal surfaces of 60 acrylic resin denture posterior teeth (Trilux-TLX and SR Orthosit PE-SRO) embedded in autopolyme...