Calcium phosphates (CaPs) are major chemical constituents of mammalian bone.Their osteoconductivity in vitro and in vivo has encouraged their use inbiomaterial applications such as implant materials and drug delivery. Highaspect ratio nanoparticles are attractive for many biomedical applications;however, precise control of the phase and morphology is challenging. The impactof fuel-to-oxidant ratio, pH, and cation chemistry on morphology and phase wasstudied for CaP-based compositions by microwave-assisted solution combustionsynthesis (MASCS) in a urea–nitrate (fuel–oxidant) system.An initial calcium to phosphate ratio of 1.5 was used. Highly crystallinehydroxyapatite (HA) and biphasic CaP nanoparticle compositions were produced asconfirmed by x-ray diffraction, scanning electron microscopy, and transmissionelectron microscopy. MASCS was capable of synthesizing high aspect ratio(∼5 to 20) single and biphasic CaP nanoparticles with diametersranging from 250 to 500 nm and lengths between 2 and 10 μm.

Photoelectrochemical cells offer a more elegant, clean, and sustainable way to store solar energy as chemical energy through the splitting of water into its primitive form (H2 and O2). Among many metal oxides pointed as candidates for this application, the fundamental characteristics of hematite (α-Fe2O3), such as abundance, excellent chemical stability in an aqueous environment, and favorable optical band gap, emerged as a promising photoanode. Although attractive, the poor optoelectronic properties necessitate a large application of overpotential for split water assisted by solar irradiation, limiting the high performance of this material. Since the electrode was built using materials in nanoscale, significant advances were achieved. This review highlights new insights and recent progress in the use of a purpose-built material process to build hematite electrodes for improving photocatalytic activity. In addition, reduction on the required overpotential by effective control-treatment of morphology and surface of vertically aligned hematite nanorods will be addressed. An interesting set of results were also discussed revisiting a novel strategy recently presented in the literature and complementary advances was illustrated. These latest efforts aid in pointing out the challenges or obstacles to be overcome using this morphology and in defining new opportunities.

The linear elastic recovery measured from the nanoindentation unloading curve of a film/substrate system was used to determine the practical work for delamination using the proposed energy balance method and to estimate the delaminated area using the Hertz contact loaded model. The practical work for delamination was then calculated by dividing the external mechanical work required for generating interfacial crack by the delaminated area. The finite element model simulation demonstrated that the energy method was feasible and the estimation of delamination area using the Hertz model was accurate. The practical works for delamination in the plasma-enhanced chemical vapor deposition SiNx/GaAs film/substrate systems estimated using this method were in the range of 1–2.3 J/m2, which were in reasonably good agreement with those obtained from our another experimental approach.

Al–7Si/gray iron bimetal composites with a sound metallurgical bonding were obtained by a gravity die casting process. The surface treatments of the gray iron specimen including fluxing and hot dipping were applied to forming a complete metallurgical bonding layer at the Al–7Si/gray iron interface. In addition, the effect of Mn in dipping bath on the microstructure of the Al–7Si/gray iron interfacial bond zone has been studied in an Al–7Si alloy containing five different levels of Mn ranging from 0 to 5 wt%. Microstructure analysis indicates that addition of Mn in dipping bath can eliminate the harmful needle-like phase (β-Al5FeSi) as the Mn content is no less than 1.5 wt% and also plays an important role in facilitating the growth of intermetallic phases [α-Al15(FexMn1−x)3Si2] and the metallurgical bonding layer. The sound metallurgical bonding formed at the Al–7Si/gray iron interface is attributed to combining the effect of surface treatments and selection of Mn content.

Benzoxazine resins are a new class of thermosetting phenolic resins that have emerged in recent decades, overcoming the traditional properties of epoxy and phenolic resins applied in the aerospace industry. The incorporation of low mass concentration of carbon nanotube (CNT) in polymer matrices can produce structural materials with superior properties. Thus, this work aims to prepare nanostructured composite benzoxazine resin/CNT and to evaluate the cure kinetic study by differential scanning calorimetry of neat benzoxazine resin and their nanostructured composites produced. Calculations of the activation energy, the reaction order, and kinetic constants are performed by a nonisothermal procedure. In general, it was observed that CNTs act as catalysts for curing the benzoxazine matrix without affecting the initial and final cure temperatures.

This study investigated the microstructure and machining characteristics of a Zr38.5Ti16.5Cu15.25Ni9.75Be20 bulk metallic glass (Zr-BMG) alloy machined using electro-discharge machining (EDM). After EDM, the hardening effect near the outer surface of the electro-discharge machined (EDMed) Zr-BMG alloy originated from the surface carbides of the recast layer, ZrC and TiC. The thickness of the recast layer, crater size, and the surface roughness increased with greater pulse energy. Furthermore, the EDM can generate a porous recast layer and convert the Zr-BMG alloy surface into a carbide surface, which is a potential method to fabricate biomaterials. Experimental results also show that the material removal rate of this alloy in the EDM process was significantly related to the pulse current IP and pulse duration τP. Many electro-discharge craters and recast materials were observed on the surface of the EDMed Zr-BMG alloy. The surface roughness of the EDMed Zr-BMG alloy was found to obey the empirical equation of Ra = β(IP × τP)α.

Copper oxide (CuO) nanosheets synthesized in polyvinylpyrrolidone (PVP) were characterized with respect to antimicrobial activity by quick precipitation method. Different sizes and shapes of CuO nanosheets were obtained by simple variations of PVP concentrations. The x-ray diffraction results revealed the formation of pure-phase CuO with monoclinic structure. Transmission electron microscopy analysis showed that the average ratio of length to width of these nanosheets increased with increasing PVP concentrations. Due to the quantum size effect, CuO nanosheets exhibit a blue shift in the ultraviolet-visible spectra. Field emission scanning electron microscopy results showed that as the concentration of PVP increased, well-defined morphologies were formed on the surface of the products. Energy dispersive analysis of x-ray clearly confirmed the presence of Cu and O with an atomic ratio of 1:1. Fourier transform infrared spectroscopy results showed that C=O in PVP coordinated with CuO and formed a protective layer. The mechanism of the reaction was also discussed. CuO nanosheets in suspension showed activity against a range of bacterial pathogens and fungi with minimum bactericidal concentrations (MBCs) ranging from 100 to 5000 µg/mL. The extent of the inhibition zones and the MBCs was found to be size-dependent.

Zn1.98Mn0.02P2O7 was synthesized by the wet chemical route. The purity of the phase and the oxidation state of manganese ion were investigated by x-ray diffraction (XRD) and electron paramagnetic resonance (EPR). Structural phase transition in α-Zn2P2O7 was investigated by high-temperature XRD (HTXRD), differential scanning calorimetry (DSC), and EPR studies. There is a distinct signature of phase transitions between 390 and 400 K in our powder sample by EPR and HTXRD. There was a sharp reduction in the volume of unit cell, while going from alpha to beta phase; with discontinuity in 405 K, which confirmed the transition to be of first order. Similarly, the effect of temperature on zero-field splitting parameter (D) also showed that there is a sudden jump (discontinuity) in the value at around 400 K (phase transition temperature) confirming the transition to be of first order. DSC studies corroborated these findings.

In the present study, polymerizable ionic liquids (ILs), 1-[n-(methacryloyloxy)alkyl]-3-methylimidazolium bromides (n = 2, 6, 7, or 10), were synthesized in high yields. Moreover, the compounds obtained (n = 6, 7, or 10) were used in the preparation of composite materials comprising a polymerized IL matrix and a nonpolymerizable IL additive, 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF4]) in various proportions (up to 75% vol/vol of [EMIM][BF4]). The UV-radiation-initiated photopolymerization process was monitored in situ by measuring the resistivities of the mixtures. An increase in [EMIM][BF4] content in the composites led to an increase in the ionic conductivities of the materials while retaining their solid state at levels as high as 40% vol/vol of the [EMIM][BF4] content. The 40% vol/vol composites had conductivities of approximately 10−4 S/cm compared to the conductivities of 10−5 S/cm for the corresponding neat polymerized ILs. Above this [EMIM][BF4] content, the materials were sticky gels, and from 50% vol/vol onwards, entirely liquid.

We develop a simple model to compute the energy-dependent decay factors of metal-induced gap states in metal/insulator interfaces considering the collective behavior of all the bulk complex bands in the gap of the insulator. The agreement between the penetration length obtained from the model (considering only bulk properties) and full first-principles simulations of the interface (including explicitly the interfaces) is good. The influence of the electrodes and the polarization of the insulator are analyzed. The method simplifies the process of screening materials to be used in Schootky barriers or in the design of giant tunneling electroresistance and magnetoresistance devices.

An extended version of self-consistent field (SCF) theory that was recentlyintroduced by the authors [Li et al., J. Chem. Phys.137, 024906, (2012)] is used to study the phase behavior of apolymer blend with reversible crosslinks. The system consists of symmetricAB diblock copolymers and homopolymers of typeA and B. We consider reversible crosslinksthat can form between the diblock copolymers with a crosslink strengthz and crosslink weights ωA and ωB for monomers of type A and B,respectively. Crosslinks between homopolymers are disabled. We present a phasediagram as a function of the A fraction of homopolymers $\phi _{\rm{\alpha }}^{{\rm{rel}}}$, the crosslink strength z, and the crosslinkasymmetry ∆ω = ωA − ωB. A hexagonal phase is found for suitably large $\phi _{\rm{\alpha }}^{{\rm{rel}}}$, and suitably small z and $\left| {\Delta {\rm{\omega }}} \right|$. Otherwise the system forms a lamellar phase. A deeper insightinto the phase behavior is gained from analyzing the free energy contributionsin the hexagonal and the lamellar phase with the help of the capabilities of theextended SCF theory developed by us.