Ni-B/TiN composite coatings with different current densities (1.5, 3.0, 4.5, and 6.0 A/dm²) have been successfully produced on a mild steel substrate using the pulsed electrodeposition (PED) method. The effect of current density on structure, morphology, hardness, tribological, and corrosion behaviors were investigated. It was found that the composite coating produced with a current density of 4.5 A/dm² exhibited, smooth surface a uniform fine compact and crack-free structure and the particles were distributed homogeneously in the metallic matrix. After the Ni-B/TiN composite coatings deposited on the substrate, samples were heat treated at 400 C for 1 h for providing precipitation of intermetallics to improve mechanical and tribological properties. In the electrochemical measurements performed in 3.5% NaCl solution by weight, the anti-corrosion ability of the composite coating was analyzed. According to the results obtained that current density is an important parameter affecting not only the deposition mechanism of Ni-B/TiN composite depositions but also microstructural, mechanical, tribological, and corrosion properties in the PED process. Accordingly, TiN particle reinforced Ni-B composite coatings deposited by the PED method are expected to be applied as a protective coating in industrial applications with excellent hardness, superior wear resistance and anticorrosion capability.

Background: Ideal suture technique and type in tendon repair are remain unclear. This biomechanical study aimed to assess the biomechanical characteristics of three techniques, modified Kessler (mKE), modified Krackow (mKR), and modified tension Bunnell (mtBU), in sheep Achilles’ tendon tear repair using three suture types, polypropylene, polyester, and ultra-high molecular weight polyethylene (UHMWPE) sutures, which are also compared. Methods: Sixty-three Achilles’ tendons harvested from sheep were transversely hacked as a replacement for rupture in a standardized measure and repaired using mKE, mKR, and mtBU techniques with No. 2 polypropylene, polyester, and UHMWPE sutures. Biomechanical parameters, such as Young’s modulus, ultimate strength, and strength to the 5-mm gap were recorded for statistical analysis. Results: The mtBU technique with UHMWPE use resulted in increased ultimate strength, strenght to 5-mm gap, Young’s modulus, and quantity of specimens with low clinical failure modes compared to other techniques with other suture materials. Furthermore, mtBU has the lowest thickness at the repair side of the tendons. This approach showed tendon failure during maximal traction testing, whereas the mKE and mKR had polyethylene and polyester suture failures. Conclusions: The UHMWPE suture was significantly superior to the other sutures in each suture techniques in terms of strength and durability. The mtBU technique using UHMWPE suture showed better biomechanical results, implying that this repair might be more appropriate to obtain early mobilization after tendon ruptures.

The production of electrically conductive concrete was introduced years ago among construction materials, generally for anti-icing. The present study investigates the electrical, mechanical, dynamic, and microstructural properties of recycled ferrochrome filled cementitious mortars, containing single-walled carbon nanotubes (SWCNTs) and steel fiber. 7, 14, and 28-day non-destructive and 28-day compressive and bending tests of cementitious conductive mortars obtained from five different mixtures were performed. Two-point uniaxial method was used to determine the electrical conductivity properties of the samples. The damping ratio of the samples was obtained by performing dynamic resonance tests. Ultrasound pulse velocity (UPV) and Leeb hardness tests were performed as other non-destructive testing methods. Microstructure analysis at the interfaces of conductive concrete samples were characterized by scanning electron microscopy (SEM), EDS (Energy-Dispersive X-ray Spectroscopy), and X-ray diffraction (XRD). According to the experimental results, all data agreed and confirmed each other. When SWCNT is used in combination with steel fiber, the conductive mortar samples exhibited reasonable conductivity, while their mechanical properties turned out to below.

Recently, it is known that carbon fiber, which is a conductive fiber, is used in different mixture designs and developing electrically conductive cementitious materials. However, the evaluation of ferrochrome as a recycled aggregate in the mixture of these special concretes has still not been investigated. In this study, electrically conductive mortars were produced by using 100% recycled ferrochrome aggregate with a particle size of less than 1 mm as filling material and using carbon fiber (CF) in 4 different ratios, 0%, 0.5%, 0.75% and 1%. 2, 14, 28, 90 and 180 days electrical resistivity properties of the obtained samples were investigated. In addition, 28-day compressive strength, flexural strength, dynamic resonance, ultrasonic pulse velocity (UPV), Leeb hardness, scanning electron microscope (SEM) and X-Ray Diffraction (XRD) tests were performed on all samples. The obtained results were compared with the literature and it was proved that ferrochrome can be used as a reasonable aggregate in conductive mortars.