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The quasistatic compressive behaviour of additively manufactured titanium-carbide (Ti-6Al4-V-C or Ti-C) was investigated through quasistatic compression and microhardness tests. The carbon content within the titanium-carbide samples was varied in order to identify the influence of graphite on the properties of the material. The information gathered through the mechanical tests and optical microscopy was used in order to identify the effectiveness of titanium-carbide as a functionally graded material applied in ballistic protection. Initial QS compression testing on 5.3 and 6 wt%C content yielded similar results in mechanical properties. This contradicts the hypothesis which predicts an increase in strength with an increase in carbon content. Further details on the results will be presented in this study.

Garleanu and Pedersen (2013) show that the optimal static portfolio policy in light of quadratic transaction costs is a weighted average of the existing portfolio and the target portfolio. In this paper, we demonstrate the importance of the robust target portfolio in the static portfolio policy that considers quadratic transaction costs. By using both empirical and simulated data, we find no evidence that the optimal dynamic portfolio policy proposed by Garleanu and Pedersen (2013) is superior to the static portfolio policy that trades towards the robust target portfolio. The robust target portfolio is achieved by either introducing time-varying covariances or restricting portfolio weights. Furthermore, the static portfolio with time-varying covariances and the short sale-constrained static portfolio are both very efficient in reducing portfolio turnover. The good performance of the static portfolio policy is robust to parameter uncertainty and trading parameters.

Ceramic reinforced metal matrix composites (MMCs) have advantages over traditional metallic materials, such as higher hardness, strength, and fracture toughness, which make them suitable for ballistic and defence applications. In this research, an in situ synthetized TiC reinforced Ti–Ni matrix sample was additively manufactured with Ti64 powders and Ni coated graphite powders. Input of Ni coated graphite powders increases from bottom to top of the sample to create a chemical gradient. Microstructure of the graded sample was examined using optical and scanning electron microscopy. The characterization results show that TiC dendrites are in situ synthesized within the metal matrix that contains α-Ti and Ti2Ni. Morphologies and proportions of these phases change with the variation of chemical composition. Mechanisms of the evolution of microstructure are further analysed. The gradual variation of microstructures indicates that 3D printed graded MMC can provide gradient properties that are preferable for ballistic applications.

Ti–Ni–C functionally graded composites were fabricated using a LENS™ additive manufacturing system. A vertical chemical gradient was created by varying powder inputs linearly from Ti–6Al–4V at the bottom layer to approximately 40%wt Ni coated graphite at the top layer. Our results show that the phase constitution, microstructure, and hardness of the composites gradually change with chemical composition. With an increasing Ni coated graphite content, the in-situ synthesised TiC precipitates are distributed more densely, and their morphologies change from tiny flakes to dendrites and finally become coralloid structures. Simultaneously, the hardness of the graded composite increases with the addition of Ni coated graphite.

Iodine-sensitized Bi4Ti3O12/TiO2 composite photocatalyst was synthesized via the formation of Bi4Ti3O12/TiO2 heterostructure followed by being loaded with I2/I−. The photocatalyst was characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, diffusive reflectance UV–vis spectroscopy and photoluminescence spectra. I-sensitized Bi4Ti3O12/TiO2 photocatalyst exhibited red shift of the absorption edge and strong enhancement of absorption in visible light region owing to the absorption of Bi4Ti3O12 and I2. I-sensitized Bi4Ti3O12/TiO2 composite displayed much higher photocatalytic activity for the photodegradation of phenol under visible light irradiation than TiO2 (P25), Bi4Ti3O12 and Bi4Ti3O12/TiO2. The enhanced photocatalytic activity of I-sensitized Bi4Ti3O12/TiO2 was attributed to its novel heterostructure and the existence of I2/I− redox mediator, both of which were responsible for its strong absorption in the visible region and low recombination rate of electron-hole pairs.

This paper investigates the meshing behavior of the roller screw, a mechanical transmission device characterized by threaded rollers that transfer a load between the nut and the screw, by analyzing the meshing characteristics between screw and rollers. This study seeks to establish a more accurate mathematical model for the thread surface by creating a modeling process in which the max radiuses of the threads are calculated more precisely. The contact line distribution and the contact location were also calculated in order to confirm the cross section of the meshing points. In the research presented in this paper, the actual transmission ratio is analyzed and the study results in a new method to calculate the actual transmission ratio. In this study, the helical angle and the vertex angle are proven to be of great significance after a careful analysis of their influence is conducted.