Studies on a novel bioactive glass and composite coating with hydroxyapatite on titanium based alloys: Effect of γ-sterilization on coating

A novel silicate based bioactive glass coating composition containing B₂O₃ and TiO₂ having matching thermal properties with that of Ti₆Al₄ V implants was developed and characterized. A conventional vitreous enamelling technique was used for coating small flat surface and curved surface of small rods. Hydroxyapatite (HAp) micro and nano-crystalline particles were used to prepare bioactive glass-HAp composite coating. Scratch testing was used to study the coating adhesion and its fracture behaviour under simulated conditions. As observed from scratch testing results, adhesion strength of the coating improved from 21 N normal load to 27 N and 32 N on addition of micro-HAp and nano HAp powder, respectively, to bioactive glass matrix. Further, sterilization of the coated samples with 25 kGy gamma irradiation substantially enhanced the adhesion of glass coating and HAp-composite coating.     

From waste to wealth: recycling the secondary resource from steel ladle as a flux in Si-killed steelmaking process

With the regulations pertaining to the environment and waste disposal becoming stringent day by day, the steelmaking industry is being compelled to adopt a zero-waste-policy for sustainability. As a consequence, 3R (reduce, reuse and recycle) technique of waste handling has become the most favoured option among the industries. This paper focuses on recycling of slag generated after secondary refining process. Trials were conducted in two stages, namely (a) prevention of dusting phenomenon of Al-killed steel ladle slag to generate lump slag by suitably selecting the ladle covering compound and chemically modifying the slag, and (b) utilisation of the lump slag as a 100% replacement of synthetic slag in Si-killed steel ladles, leading to a reduction in its specific consumption from 1.2?kg/TLS to zero. As a process requirement, specific power consumption, arcing time and degree of desulphurisation were considered as the major parameters for comparing the results using hypothesis test statistical tool.     

封闭水循环的制浆厂如何应对无机沉积物的形成

随着环保压力的不断增加,清水用量已经成为多数制浆厂重点关注的指标。为了满足持续趋紧的排放标准,水系统封闭已成为一种必然趋势。这种趋势对制浆厂产生了重大的影响。由于受制浆原料的限制,亚洲许多浆厂采用非木材原料替代木材原料制浆。即使采用木材原料制浆的工厂,因使用圆木很多是未剥皮的,而树皮中含有的无机盐成分如钙、硅、镁、磷、铝及铵盐等均是导致无机沉积物的主要成分。在制浆过程中通常定义为非过程元素。非木材类制浆原料（主要指农作物秸秆）非过程元素含量相当高。随着无氯漂白及降低成本等诸多因素更复杂的改变,均会导致越来越多的无机和有机沉积物。这些非过程元素和不断封闭的水系统正逐渐成为提高制浆厂运行性能的极大挑战。文中着重介绍采用特殊化学品控制无机沉积物,为减轻浆厂的此类挑战提供解决方案。     

Defect‐Related Emissions and Magnetization Properties of ZnO Nanorods

A clear correlation between defect‐related emissions and the magnetization of ZnO nanorods synthesized by a one‐step aqueous chemical method is demonstrated. The relative contribution of the emission bands arising from various types of defects is determined and found to be linked with the size of the nanorods and annealing conditions. When the size of the nanorods and the annealing temperature are increased, the magnetization of pure ZnO nanorods decreases with the reduction of a defect‐related band originating from singly charged oxygen vacancies ($V_{\rm o}^ +$ ). With a sufficient increase of annealing temperature (at 900 °C), the nanorods show diamagnetic behavior. Combining with the electron paramagnetic resonance results, a direct link between the magnetization and the relative occupancy of the singly charged oxygen vacancies present on the surface of ZnO nanorods is established.     

Mobility enhancement of solution-processed Poly(3-Hexylthiophene) based organic transistor using zinc oxide nanostructures

This work reports the mobility enhancement of p-type organic transistors formed using Poly(3-Hexylthiophene) (P3HT) using the dispersion of ZnO (zinc oxide) nanostructures. The ZnO nanostructures considered here are nanorods that were fabricated via a simple one-step aqueous-based chemical approach. Organic Thin Film Transistors (OTFTs) based on these nanocomposites show a mobility enhancement of more than 60% for the P3HT/ZnO nanorod composite compared to its pristine state polymer devices. The results presented here show a great promise for the mobility enhancement of p-type solution processed OFETs and applications.     

Development of an environmentally friendly protective coating for the depleted uranium-0.75 wt.% titanium alloy: Part IV. Vibrational spectroscopy of the coating

Molybdenum oxide based conversion coatings have been formed on the surface of the depleted uranium-0.75 wt.% titanium alloy and the coating structure was found to undergo changes as it ages. Raman and Fourier transform infrared (FT-IR) spectroscopies have been performed to examine these changes. Raman spectroscopic measurements indicate that the coating is based on an octamolybdate structure and FT-IR experiments show that uranyl hydroxide is present in the as-made coating but no longer apparent in the aged coatings, supporting the proposed mechanism describing the aging of the coating. Both techniques show that none of the molybdenum is in the form of tetrahedral molybdates.     

High Piezoelectric Longitudinal Coefficients in Sol–gel PZT Thin Film Multilayers

A five‐layer stack of lead zirconate titanate (PZT) thin films with Pt electrodes was fabricated for potential applications in nanoactuator systems. The 1 μm thick PZT films were deposited by a sol–gel technique, the platinum electrodes by sputtering. The PZT films were crack‐free, in spite of the use of silicon as a substrate, suggesting an increased toughness of the metal–ceramic composite. For piezoelectric characterization, the intermediate electrodes were liberated by successive etching of the PZT and Pt layers, obtaining a functional three‐ layer stack. A total thickness change of 5.2 nm was achieved with 10 V, measured by double beam laser interferometry. The small signal response was obtained as 0.49 nm/V. Finite element simulations were made to account for the thickness change in the substrate due to the transverse piezoelectric effect. The average response corresponds to an average d_33,f of 120 pm/V. The multiple annealed buried layers show clearly a better performance with up to 175 pm/V. It is concluded that the electrode interfaces in the interior exhibit higher qualities, as supported by transmission electron microscopy, and that the multiple anneals were beneficial for PZT thin film quality.     

Model reference control of non-linear systems with relative order two: application to a semibatch reactor

The design of a robust non-linear feedback controller incorporating integral and derivative actions is presented for non-linear systems with relative order two. The design method is applied to product concentration tracking in the case of parallel reactions occurring in a semibatch isothermal reactor. The simulation results show the effectiveness of the control scheme and its robustness to modelling errors.