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Hydroxyapatite, tricalcium phosphate, and a mixture of these, i.e biphasic calcium phosphate (BCP), are widely employed as ceramic materials in hard tissue engineering, despite their poor mechanical and functional properties. The method of ionic substitution inside their lattice structures has been examined extensively by researchers in their long efforts to develop materials, that closely resemble natural hard tissues. The presence of dopants has a deep impact on the phase assemblage, structural, and functional behaviors of BCP. In this context, the goal of the current article is to cover different aspects of ongoing research on doped biphasic calcium phosphate. Apart from providing brief descriptions of different synthesis routes for producing ion-modified BCPs, the limitations of each technique are also discussed. In addition, particular emphasis has been given to describing the key experimental results, which elucidate the structural changes occurring due to doping. In particular, the preferable substitution sites of different dopant ions and the resulting crystallographic changes are depicted quite elaborately. Finally, the effects of substitution on biological and mechanical properties of BCP are briefly mentioned. In summary, the present review focuses on the ionic substitutions in BCP systems and their collective effects on material behaviors.

The steady-state magneto-mechanical response of a magnetorheological fluid (MRF), prepared by dispersing 40 wt % of magnetically soft, light-weight coral-network-shaped yttrium iron garnet (YIG; Y3Fe5O12) powder in silicone oil (140 cSt) is studied as a function of shear rate, under different applied magnetic fields (B). The results show that the yield strength (tau(Y)) and viscosity (eta) of the MRF increase with B, and are strongly influenced by the physical parameters of the particles such as morphology and saturation magnetization. The low density of the YIG-particles, leading to higher volume fraction for equal mass loading, results in a higher viscosity in the absence of a magnetic field, in comparison to that of conventional metallic Fe-particle-based MRFs. Due to this, there is a relatively smaller increase in tau(Y) and eta when the magnetic field is switched on. The YIG-particles-based MRF has the advantages of high chemical stability, thermo-oxidative resistance and low-cost.

We report the phase-composition, structure and magnetic properties of two representative samples of naturally available iron-oxide containing ores/soils collected from two different regions in Karnataka, India. Presence of elements such as Fe, Si, Al and O were identified in both the samples using energy dispersive analysis of X-rays (EDAX). X-ray diffraction results confirmed that different ceramic phases such as crystalline iron oxide phases (Fe3O4, γ-Fe2O3 and α-Fe2O3), aluminosilicates (Al2SiO5) and low-quartz (SiO2) phases constitute the soil. The presence of ferrimagnetic phases (Fe3O4, γ-Fe2O3) makes the soil respond to a permanent magnet. Separation between the magnetic and non-magnetic phases was performed using a permanent magnet. The non-magnetic part of the sample contains a high amount of α-Fe2O3 phase along with aluminosilicates and low-quartz. The magnetic phases were further characterized and quantified. The presence of Fe3O4 phase in the samples was confirmed from the Verwey transition observed by internal-field NMR spectroscopy. Our results demonstrate that internal-field NMR and Mössbauer spectroscopy are complementary tools for characterizing iron containing soils. Furthermore, we found that the soil collected from the low temperature region (Sandur) contains more amounts of ferrimagnetic oxide (Fe3O4, γ-Fe2O3) phases, whereas the high temperature region (Hospete) contains more α-Fe2O3 phase. Hence, our results confirm that the phase composition of the soil is intimately related to the local daily temperature. Keywords: Iron ores, Phase composition, Magnetic properties, Internal field NMR, Mössbauer spectroscopy

Magnetorheological fluids have tunable magneto-mechanical strength. We report the magneto-mechanical (steady-state shear) response of magnetorheological fluids (MRFs) containing bi-disperse Mn-Zn ferrite (Mn0.7Zn0.3Fe2O4) spherical particles synthesized by a solvothermal method. Using a model of magnetic dipolar interactions between the particles, we have explained the origin of the magneto-mechanical response of the MRFs. The observed yield strength values of our MRFs increase with the applied magnetic field strength and the concentration of the ferrite particles in the fluid due to the formation of strong columnar structures which resist the shear. Moreover, the yield strength of the MRFs was found to depend strongly on the particle size, size distribution and the magnetic nature (saturation) of the particles. We have demonstrated that a bi-disperse size distribution of particles in the fluid imparts superior yield strength to the MRF compared to that of the mono-disperse particles. Unlike conventional metallic iron particles, which lead to dispersion instability and are prone to corrosion and thermo-oxidative failures, the low-density corrosion-resistant soft-ferrimagnetic Mn-Zn ferrite particles make our MRF system dependable for various technological applications demanding shock absorption and vibration isolation.

Layered sodium iron phosphate phase [Na3Fe3(PO4)4] was synthesized by solution combustion synthesis method, marking the first attempt of solvothermal synthesis of this phase. Its crystal structure was verified by synchrotron and neutron powder diffraction. Rietveld analyses proved the phase purity and formation of monoclinic framework with C2/c symmetry. It undergoes an antiferromagnetic ordering ∼27 K. This combustion prepared nanoscale Na3Fe3(PO4)4 compound was found to be electrochemically active with a stepwise voltage profile involving an Fe3+/Fe2+ redox activity centred at 2.43 V vs. Na/Na+. Despite various cathode optimization, only 1.8 Na+ per formula unit could be reversibly inserted into the Na3Fe3(PO4)4 framework leading to capacity close to 50 mAh g−1. This limited electrochemical activity can be rooted to (i) relatively large diffusion barrier (ca. 0.28 eV) as per Bond valence site energy (BVSE) calculations and (ii) possible structural instability during (de)sodiation reaction.

Among ultra high temperature ceramics (UHTCs), ZrB2-based ceramics have received the most attention for applications in hypersonic space vehicles. However, UHTCs encounter several challenges pertaining to their processing to achieve the desired properties in order to optimally exploit their potential. In this perspective, the present work illustrates some of the sintering related challenges using a case study of ZrB2-SiC based ceramics. Multi stage spark plasma sintering is carried out on ZrB2-SiC based ceramics at 1500 degrees C with metallic Titanium as sinter-aid. High hardness of up to 28 GPa is obtained in dense ceramics with finer microstructure. Furthering towards design and fabrication of real scale hypersonic application such as thermal protection system, efforts have been taken to prove the scalability of the ceramics by consolidating up to phi 100 mm ceramic discs.

We report the steady-state shear response of polydisperse Ni-Zn ferrite-submicrospheres-based magnetorheological fluids (MRFs). The Ni-Zn ferrite spherical particles were prepared by solvothermal method. MRFs of three different concentrations (10, 20 and 40 wt%) were prepared by dispersing Ni-Zn ferrite submicrospheres in silicone oil. These MRFs were subjected to steady-state shear conditions, at different applied magnetic fields. Dynamic yield strength values corresponding to different applied field strengths showed increase in value with increase in magnetic field strength. Furthermore, the dynamic yield strength scaled up with the concentration of Ni-Zn ferrite spherical particles in the carrier fluid. Comparison of the dynamic yield strengths for the MRFs showed that the values depend strongly on the physical properties of the particles such as the particle size, size-distribution (polydispersity) and the saturation magnetization. (C) 2018 Elsevier B.V. All rights reserved.

Research efforts in large area graphene synthesis have been focused on increasing grain size. Here, it is shown that, beyond 1 μm grain size, grain boundary engineering determines the electronic properties of the monolayer. It is established by chemical vapor deposition experiments and first-principle calculations that there is a thermodynamic correlation between the vapor phase chemistry and carbon potential at grain boundaries and triple junctions. As a result, boundary formation can be controlled, and well-formed boundaries can be intentionally made defective, reversibly. In 100 µm long channels this aspect is demonstrated by reversibly changing room temperature electronic mobilities from 1000 to 20,000 cm2 V−1 s−1. Water permeation experiments show that changes are localized to grain boundaries. Electron microscopy is further used to correlate the global vapor phase conditions and the boundary defect types. Such thermodynamic control is essential to enable consistent growth and control of two-dimensional layer properties over large areas., Engineering the grain boundary size of chemical vapor deposited monolayer graphene can reversibly tune its electronic properties. Here, the authors report a thermodynamic correlation for 100 μm long channels in graphene by reversibly changing its electronic mobilities from 1,000 to 20,000 cm2 V−1 s−1.

The biophysical cues of endogenous origin, i.e., shear stress and electric field, are known to significantly modulate cell functionality, in vitro. While this has been relatively well investigated in conventional petri dish culture, it is important to validate such important phenomenon in physiologically simulated cellular microenvironment. In this perspective, this review critically discusses the importance of lab-on-a-chip (LOC)-based microfluidic devices to probe into this aspect to develop an insight towards the application in regenerative medicine. While reviewing several literature reports, an emphasis has been placed to unravel the intriguing aspects of shear and electric field modulated differentiation of stem cells in the biomicrofluidics devices. The potential application focusing the stem cell culture was emphasized in this article as the stem cells are the foundation of tissue regeneration. Several challenges in tissue regeneration and introduction of personalized medicine could be addressed through microfluidic technology. Culturing of organ-specific multiple cell types within lab-on-a-chip and biophysical stimulation mediated activations of intracellular signal transduction under gradient shear/electric field are highlighted in this review. Lay Summary: Conceptually, regenerative medicine is considered as an emerging approach for treating traumatized, malfunctional anatomical parts of the patients with stem cells to establish normal functionality of the tissue. The regenerated tissue should preferably be the patients� autologous tissue, grown under artificially created in vivo physiological environment. Biomicrofluidic-based lab-on-a-chip technology enables to perform in vitro cell/tissue engineering under endogenous cues, like shear and electric field. Therefore, this review discusses two aspects of regenerative medicine in terms of autologous transplantation of cells/tissues to improvise personalized regenerative medicine and to recreate an organ-specific tissue under the influence of biophysical stimulation in an attempt to improve the physiological functionality.

We report the physicochemical insight into the role of coral-shaped yttrium-iron-garnet (YIG) particles for high electromagnetic interference (EMI) shielding behaviour of YIG-polyaniline (PANI)-Wax composites. We studied the total shielding effectiveness (SET) of various compositions of the composites in X and K-u-band frequencies (8-18 GHz) and came upon with a critical concentration (20 wt% of YIG) for which SET is maximum (-44.8 dB). At this critical concentration, the coral shape of YIG helps in effectively increasing the YIG-PANI interfaces necessary for the multiple scattering of electromagnetic (EM) waves. The scattered microwave is then trapped within the dense coral-network of YIG until they are absorbed therein by PANI via conduction loss; thereby, dramatically enhancing the microwave attenuation. The detailed EMI shielding mechanism is explained based on electrical and magnetic properties of the composites. Our result demonstrates the importance of morphology of the dielectric/magnetic particles and their concentration in the composites for designing an efficient EMI shield.

The benchmarking of Fe3+/Fe2+ redox potential at 3.8 V (versus Na) in alluaudite-type Na2Fe2(SO4)(3), along with fast rate kinetics and excellent cycling stability (Nat. Commun., 5, 4358, 2014) has opened up new era of research in Na-ion research. Further insight to the reported material show synthesis is a careful solid-state method involving (a) formation of anhydrous FeSO4 from commercial FeSO4 center dot 7H(2)O, (b) prolonged milling and (c) longer annealing (350 degrees C, 24 h). Journey of such materials from laboratory to industry warrants economic, sustainable and scalable synthesis. Here, we report novel solution assisted-Ionothermal, aqueous spray-drying and pechini synthesis of Na2Fe2(SO4)(3), M = 3d metals] alluaudite cathodes. It will approach (i) salient feature of synthesis, (ii) structure/polymorphism, (iii) magnetic properties and (iv) electrochemical properties of Na2Fe2(SO4)(3) cathode materials. (C) 2018 Elsevier Ltd. All rights reserved.

We report the synthesis of single crystalline octahedron-shaped magnetite microcrystals, the preparation of magnetorheological fluids (MRFs) and their magnetorheological properties under steady-state shear conditions. The magnetite microcrystals were synthesized via the template-free hydrothermal route. MRFs with three different particle concentrations (10, 20 and 40 weight%) were prepared and were subjected to steady shear conditions at various externally applied magnetic fields of strength up to 1.2 T. The shear rates were chosen up to high enough values to observe the yield behaviour of the MRFs. The dynamic yield strengths of MRFs, estimated using the Bingham plastic model fit to the steady-state shear response curves, showed that they scale-up with the applied magnetic field strength and amount of magnetic particles in the fluid. The origin of the mechanical strength in the MRFs due to the inter-particle interaction is explained using a simple dipolar model. The observed high yield strengths of the MRFs were explained on the basis of the particle shape (octahedrons) and magnetic nature (saturation magnetization). By comparing the values of the yield strength with the on-state to off-state viscosity ratio for the MRFs (for each particle concentration), an optimum content of particles in the carrier fluid to obtain high efficiency is suggested. Because the particles are single crystalline, the off-state viscosity of the MRFs even at the highest studied (40 wt%) particle concentration was very low, which is ideal for their application as quickly responding MRFs.

The present article deals with effect of Cr addition (10 at.%) on the partitioning behavior and the consequent effect on mechanical properties for tungsten-free gamma-gamma' cobalt-based superalloys with base alloy compositions of Co-30Ni-10Al5Mo- 2Ta (2Ta) and Co-30Ni-10Al-5Mo-2Ta-2Ti (2Ta2Ti). Cr addition leads to a change in the morphology of the strengthening cuboidal-shaped gamma' precipitates to a spherical shape. The site preference of Cr atoms in two alloy systems (with and without Ti) has been experimentally investigated using atom probe tomography with the supportive prediction from first principles DFT-based computations. Cr partitions more to the c matrix relative to gamma'. However, Cr also has a strong effect on the Ta and Mo partitioning coefficient across gamma/gamma' interfaces. The value of partition coefficient for Mo (K-Mo) becomes

Hybrids based on supported nanoparticles are used for many applications such as catalysis and sensing. It is well-known that the size and shape of the particles and: their interaction with the substrate play a key role in controlling the properties, of the hybrid. Here, we show that in addition to these commonly considered effects, the orientation Of the partide,on the:substrate could play a critical role that could dominate over the other effects. For the same nominal size of the particle, changes in its orientation on the substrate lead, to dramatic changes in the accessible, surface, area and the electronic structure, Thus profoundly affecting the properties. Using analytical calculations, we show that the orientation of the crystal, heterogeneously nucleating on; substrate, is determined by the, barrier for nucleation and experimentally demonstrate that it is possible to tune. this orientation by tuning the interfacial energy between the, nucleus and substrate. Our study provides some fundamentally new insights into the process, of heterogeneous nucleation, that can be exploited for practical applications.

In this paper we have presented an in-depth study of effect of metallic precursor stacking order on the growth of the Cu 2 ZnSnS 4 (CZTS) thin films. The CZTS films were prepared by employing a two-step process comprising of sequential sputtering of the metal precursors followed by sulfurization. An optimized stacking sequence as well as growth mechanism for obtaining the single phase CZTS has been proposed based on the results of XRD, Raman, XPS, UV–Vis and electrical studies. A combination of Raman analysis and XPS has been carried out to confirm the CZTS phase formation and to detect any minor phases, if present. The occurrence of Raman modes at around 286 and 336 cm −1 for the Zn/Cu/Sn/Cu stack sulfurized at 500 °C indicated the existence of prominent Kesterite CZTS phase. The perfect homogeneous mixing of sequential precursors together with the elemental sulfur was observed in the case of sulfurized stack order of Zn/Cu/Sn/Cu, which yielded single phase CZTS films, and further confirmed by high resolution core level XPS measurements. Stack dependent micro structural features and elemental analysis were also carried out using FESEM attached to EDS. The p-type charge carriers as detected using hot-probe measurement technique and the band-gap energy of ∼1.52 eV as estimated from the absorbance spectrum, suggested that the Zn/Cu/Sn/Cu stack order is most appropriate for realizing single phase CZTS growth using two step method.

Nanoscaled Sn–Cd alloy particles with a nominally equiatomic composition and size in the range of 5–120 nm, embedded in an Al matrix, have been synthesized by rapid solidification processing. The orientation relationship between tin, cadmium and aluminum is given by $$ \begin{aligned} & (10\bar{1})_{\text{Al}} ||(0\bar{1}0)_{\text{Sn}} ||(1\bar{2}10)_{\text{Cd}} \\ & [111]_{\text{Al}} ||[101]_{\text{Sn}} ||[0001]_{\text{Cd}} \\ \end{aligned} $$ . Particles in the size range 5–25 nm display a single-phase hcp structure, while particles with size range of 25–120 nm size are found to be phase-separated into a tin-rich phase with bct structure and a cadmium-rich phase with hcp structure. In situ heating studies in the transmission electron microscope indicate that particles having a size range of 5–18 nm always display a single-phase microstructure right up to the melting point and subsequent cooling. The in situ heating experiments revealed complex pathways for transformation for particles having size between 18 and 30 nm. The as-solidified microstructures of over 75% of the particles analyzed, exhibit a two-phase structure in the melt-spun samples. While more than 75% of the particles analyzed by in situ heating and cooling experiments reveal formation of a single-phase structure during resolidification, some of the particles on cooling from molten state solidify into a two-phase microstructure of cadmium and tin solid solution. These particles, on cooling in the microscope, transform to single-phase particles of cadmium-rich solid solution around 110 °C suggesting a kinetically dominated microstructure evolution. In contrast, the particles in the size range 30–120 nm exhibit a two-phase microstructure both during heating and cooling. Size-dependent alloying behavior of the particles could be explained based on models that consider capillary pressure and interfacial energies.

The colored solar-thermal collectors can provide advantages of architectural integration over energy performance. The colour appearance of the solar-thermal collectors can be achieved by increasing the number of layers. W/WAlN/WAlON/Al2O3 coating, fabricated by DC and RF magnetron sputtering showed a high solar absorptance of 0.948 and the low thermal emittance of 0.08 with a sky blue color appearance. The tandem absorber exhibited excellent long-term thermal stability at 500 degrees C in air for 150 h. The absorber deposited on SS substrates showed high solar selectivity (alpha/epsilon) of 0.918/0.11, even after heat treatment in air up to 500 degrees C for 100 h. The selective performance of the coating can be stable more than 25 years. The humidity test confirms the significant moisture resistant of the coating. In summary, the new W/WAlN/WAlON/Al2O3-based coating with its colourful appearance is appropriate to be used in solar thermal collectors. (C) 2016 Elsevier B.V. All rights reserved.

Water dissociation, in general, requires external stimuli such as light energy or electricity. Here, we present a stimuli-free water dissociation using mesoporous SnO2-based hydroelectric cell that can directly be exploited to generate electric power for portable applications. The device configuration is almost identical to metal-air batteries but follows altogether a different reaction pathway. The mesoporous SnO2-based hydroelectric cell dissociates water molecule into hydroxyl ions (OH-) and hydronium ion without any stimuli, transports hydronium ions to the opposite end, and simultaneously acts as the separator. The OH- react with Al electrode to release the electrons, whereas hydronium ions get reduced at the Ag electrode to produce a potential difference as high as similar to 1000 +/- 20 mV between the electrodes that is stable over 3500 hours. The device also shows its potential toward electric power generation from atmospheric moisture with the help of CuO layer that acts as moisture pump.

Hysteresis loops exhibited by the thermal properties of undoped and 0.8 at.% W-doped nanocrystalline powders of VO2 synthesized by means of the solution combustion method and compacted in pellets, are experimentally measured by photothermal radiometry. It is shown that: (i) the W doping reduces both the hysteresis loops of VO2 and its transition temperature up to 15 °C. (ii) The thermal diffusivity decreases (increases) until (after) the metallic domains become dominant in the VO2 insulating matrix, such that its variation across the metal-insulation transition is enhanced by 23.5% with W-0.8 at.% doping. By contrast, thermal conductivity (thermal effusivity) increases up to 45% (40%) as the metallic phase emerges in the VO2 structure due to the insulator-to-metal transition, and it enhances up to 11% (25%) in the insulator state when the local rutile phase is induced by the tungsten doping. (iii) The characteristic peak of the VO2 specific heat capacity is observed in both heating and cooling processes, such that the phase transition of the 0.8 at.% W-doped sample requires about 24% less thermal energy than the undoped one. (iv) The impact of the W doping on the four above-mentioned thermal properties of VO2 mainly shows up in its insulator phase, as a result of the distortion of the local lattice induced by the electrons of tungsten. W doping at 0.8 at.% thus enhances the VO2 capability to transport heat but diminishes its thermal switching efficiency.

This paper reports the development of mechanically flexible reflective coatings of Cu-Al intermetallic alloy on flexible glass (PG) substrates for possible concentrated solar power application. Thin films of Cu-Al intermetallic alloys were deposited on 100 mu m thick FG substrates using resistive thermal evaporation of arc melted Cu-Al bulk alloy. At the optimized evaporation conditions, smooth intermetallic alloy thin films with homogeneous composition (Cu0.78Al0.22) were obtained. At a coating thickness of 160 nm, average specular and total reflectance of similar to 84% and similar to 92% respectively, were achieved. The films exhibited hydrophobic nature with a contact angle of 102 degrees, implying the possibility of developing a self-cleaning ability. The analytical calculation involving alloy compositional dependence of plasma frequency reveals the prospect of further modulating the reflectance property by carefully tailoring thin film composition. Additionally, hard intermetallic thin film provides the opportunity of developing mirrors that may not require top protective coatings.

Electron Backscattering Diffraction (EBSD) is a well-known technique which is primarily used to analyse the microstructural features in metallic materials, including the orientation relationship between microstructural constituents. However, its versatility has not yet been critically utilized to establish crystallographic relationships involved in phase transformation of ceramics. In view of the significance of transformation twinning in ceramics on mechanical properties, the representative orientation relationships in twinned grains of CaTiO3 is investigated using EBSD. It is observed that the matrix/twin pairs of CaTiO3 have misorientation angles at 87°, 90° and 98°. The misorientations associated with the boundaries between twin/twin pairs formed by different twinning orientation relationships are noted at 90°, 91°, 92° and 98°. On the basis of the orientation relationships, the crystallography of cubic to orthorhombic and tetragonal to orthorhombic phase transformations in CaTiO3 is explored. The most favorable orientation relationships pertaining to such a phase transformation are ( 001 ) o [ 100 ] o || ( 03 1 ¯ ) c [ 3 ¯ 13 ] c between parent cubic and daughter orthorhombic phases and ( 001 ) o [ 100 ] o || ( 1 1 ¯ 2 ¯ ) t [ 8 ¯ 2 ¯ 3 ¯ ] t between parent tetragonal and daughter orthorhombic phases of CaTiO3.

High-density polyethylene (HDPE)-based and ultra-high molecular weight polyethylene (UHMWPE)-based composites with carbonaceous reinforcements are being widely investigated for biomedical applications. The enhancement of material properties critically depends on the nature, amount and compatibility of the reinforcement with the polymeric matrix. To this end, this study demonstrates the efficacy of a ‘dual’ hybrid approach of incorporating modified inorganic nanofiller into an optimized polyethylene blend. In particular, a unique synthesis strategy was adopted to design a covalently bonded maleated polyethylene (mPE) grafted modified graphene oxide (mGO) hybrid nanocomposite. In this scheme, polyethyleneimine (PEI) was initially attached onto GO to synthesize amine functionalized GO (GO–PEI). This is followed by mPE grafting, resulting in mGO. Melt-extrusion together with injection moulding of a polymer mix (60% HDPE–40% UHMWPE) with different proportions (less than or equal to 3 wt%) of surface functionalized GO was conducted to develop nanocomposites of different sizes and shapes. When compared with unreinforced PE blend, the nanocomposites with 1 wt% mGO exhibited an increase in ultimate tensile strength by 120% (up to 65 MPa) and elastic modulus by 40% (up to 908 MPa). The uniform dispersion of modified GO nanofillers, confirmed using X-ray micro-computed tomography and transmission electron microscopy, facilitated effective interfacial adhesion and compatibility with the hybrid polymer matrix. The variation in mechanical properties with GO/mGO addition to PE blend was critically discussed in reference to the structural modification of GO, crystallinity and nature of dispersion of fillers. Importantly, the nanocomposites support the attachment and proliferation of C2C12 murine myoblast cells over 3 days in culture in a statistically insignificant manner with respect to polymer blends without any nanofiller. Taken together, the experimental results suggest that HDPE/UHMWPE/mGO is a promising biomaterial for bone tissue engineering applications.

A self-powered, broad band and ultrafast photodetector based on n + -InGaN/AlN/n-Si(111) heterostructure is demonstrated. Si-doped (n + type) InGaN epilayer was grown by plasma-assisted molecular beam epitaxy on a 100 nm thick AlN template on an n-type Si(111) substrate. The n + -InGaN/AlN/n-Si(111) devices exhibit excellent self-powered photoresponse under UV-visible (300-800 nm) light illumination. The maximum response of this self-powered photodetector is observed at 580 nm for low-intensity irradiance (0.1 mW/cm 2 ), owing to the deep donor states present near the InGaN/AlN interface. It shows a responsivity of 9.64 A/W with rise and fall times of 19.9 and 21.4 I¼s, respectively. A relation between the open circuit voltage and the responsivity has been realized.

A number of bioengineering strategies, using biophysical stimulation, are being explored to guide the human mesenchymal stem cells (hMScs) into different lineages. In this context, we have limited understanding on the transdifferentiation of matured cells to another functional-cell type, when grown with stem cells, in a constrained cellular microenvironment under biophysical stimulation. While addressing such aspects, the present work reports the influence of the electric field (EF) stimulation on the phenotypic and functionality modulation of the coculture of murine myoblasts (C2C12) with hMScs [hMSc:C2C12=1:10] in a custom designed polymethylmethacrylate (PMMA) based microfluidic device with in-built metal electrodes. The quantitative and qualitative analysis of the immunofluorescence study confirms that the cocultured cells in the conditioned medium with astrocytic feed, exhibit differentiation towards neural-committed cells under biophysical stimulation in the range of the endogenous physiological electric field strength (8 ± 0.06 mV/mm). The control experiments using similar culture protocols revealed that while C2C12 monoculture exhibited myotube-like fused structures, the hMScs exhibited the neurosphere-like clusters with SOX2, nestin, βIII-tubulin expression. The electrophysiological study indicates the significant role of intercellular calcium signalling among the differentiated cells towards transdifferentiation. Furthermore, the depolarization induced calcium influx strongly supports neural-like behaviour for the electric field stimulated cells in coculture. The intriguing results are explained in terms of the paracrine signalling among the transdifferentiated cells in the electric field stimulated cellular microenvironment. In summary, the present study establishes the potential for neurogenesis on-chip for the coculture of hMSc and C2C12 cells under tailored electric field stimulation, in vitro.

Among additive manufacturing (AM) techniques, laser or electron beam based processes have been widely investigated for metallic implants. Despite the potential in manufacturing of patient-specific biomedical implants, 3D inkjet powder printing (3DLIPP, a variant of AM) of biomaterials is still in its infancy, as little is known quantitatively about the transient process physics and dynamics. An equally important challenge has been the ink formulation to manufacture biomaterials with reliable mechanical properties and desired biocompatibility. We have developed, for the very first time, the theoretical foundation and experimental formulation of a unique process strategy involving the `on-demand' delivery of a novel in situ polymerisable acrylic ink system to print a model biomaterial, Ti-6Al-4V. The post-ejection in-flight dynamics of ink droplets have been captured in situ by employing high speed stroboscopic shadowgraphy, to quantitatively estimate the dimensionless numbers of fluid physics for `printability' assessment. Washburn model was adapted extensively to quantify the capillary ink infiltration time in porous powder bed of finite thickness. On the other hand, particle tracking mode in diffusing wave spectroscopy (DWS) was exploited to analyse the timescale for effective binding of powder particles during in situ polymerisation. The clinically relevant combination of 3D porous architecture with 98.4% interconnectivity among 10-40 mu m pores together with modest combination of elastic modulus (4 GPa) and strength reliability (Weibull modulus similar to 8.1) establish the potential of inkjet printed Ti-6Al-4V as cortical bone analogue. A better cell attachment, viability, cytoskeletal spreading with pronounced proliferation of murine fibroblasts and pre-osteoblasts on 3DIJPP Ti-6Al-4V, when benchmarked against the metallurgically processed (commercial) or selective laser melted (SLM) Ti-6Al-4V, has been demonstrated, in vitro. The enhanced cellular activities on the 3DIJPP Ti-6Al-4V was explained in terms of an interplay among the elastic stiffness, surface roughness and wettability against the same benchmarking. It is conceived that the quantitative understanding of the integrated process physics and dynamics to print Ti-6Al-4V with reliable mechanical properties together with better cytocompatibility can lead to a paradigm shift in adapting the scalable 3DIJPP for manufacturing of metallic biomaterials.

Energy-savvy auto-combustion synthesis was used to form the porous BaLi2Ti6O14 titanate anode. It registered the lowest calcination temperature (800 degrees C) along with the shortest calcination duration (2 h). Rietveld analysis confirmed the purity of the orthorhombic (s. g. Cmca) product phase. The bond valence site energy analysis indicated a 1D ionic conduction along c axis with low activation energy and 2D pathways along (010) with high activation energy. AC conductivity analysis revealed a bulk conductivity of 2.41 x 10(-4) S/cm (at 300 degrees C) with a moderate activation energy barrier (0.68 eV). From cyclic voltammetry, the Li+ diffusion coefficient was calculated to be 10(-11)-10(-12) cm(2)/s. The as-synthesized BaLi2Ti6O14 reversibly intercalated; similar to 1.3 Li+ involving a 1.42 V Ti4+/Ti3+ redox activity delivering capacity; similar to 100 mA h/g with good cyclability over 100 cycles. Furthermore, BaLi2Ti6O14 was found to reversibly intercalate similar to 0.89 Na+. With suitable diffusional and electrochemical performance, BaLi2Ti6O14 form a safe titanate anode for secondary batteries.

Robust electrocatalysts toward the resourceful and sustainable generation of hydrogen by splitting of water via electrocatalytic hydrogen evolution reaction (HER) are a prerequisite to realize high-efficiency energy research. Highly electroactive catalysts for hydrogen production with ultralow loading of platinum (Pt) have been under exhaustive exploration to make them cutting-edge and cost-effectively reasonable for water splitting. Herein, we report the synthesis of hierarchically structured nickel pyrophosphate (beta-Ni2P2O7) by a precipitation method and nickel phosphate (Ni-3(PO4)(2)) by two different synthetic routes, namely, simple cost-effective precipitation and solution combustion processes. Thereafter, Pt-decorated nickel pyrophosphate and nickel phosphate (beta-Ni2P2O7/Pt and Ni-3(PO4)(2)/Pt) were prepared by using potassium hexachloroplatinate and ascorbic acid. The fabricated novel nickel pyrophosphate and nickel phosphate/Pt materials were utilized as potential and affordable electrocatalysts for HER by water splitting. The detailed electrochemical studies revealed that the beta-Ni2P2O7/Pt (1 mu g.cm(-2) Pt) electrocatalyst showed excellent electrocatalytic performances for HER in acidic solution with an overpotential of 28 mV at -10 mA.cm(-2), a Tafel slope of 32 mV.dec, and an exchange current density (j(0)) of -1.31 mA.cm(-2), which were close to the values obtained using the Vulcan/Pt (8.0 mu g.cm(-2) Pt), commercial benchmarking electrocatalyst with eight times higher Pt amount. Furthermore, the beta-Ni2P2O7/Pt electrocatalyst maintains an excellent stability for over -0.1 V versus RHE for 12 days, keeping j(0) equal after the stability test (-1.28 mA cm(-2)). Very well-distributed Pt NPs inside the cages on the beta-Ni2P2O7 structure with a crystalline pattern of 0.67 nm distance to the Ni2P2O7/Pt electrocatalyst, helping the Volmer-Tafel mechanism with the Tafel reaction as a major rate-limiting step, help to liberate very fast the Pt sites after HER. The high electrocatalytic performance and remarkable durability showed the beta-Ni2P2O7/Pt material to be a promising cost-effective electrocatalyst for hydrogen production.

Lead lithium titanate (PbLi2Ti6O14) was synthesized by combustion route restricting the annealing at 900 degrees C to just 1 minute. Rietveld analysis confirmed orthorhombic (Cmca) product phase with an average particle size similar to 200 nm and surface area of 2 m(2)/g forming secondary porous particles. From bond valence site energy (BVSE) calculations, 1 D ionic conduction was found along c axis with low activation energy (0.23 eV). AC conductivity analysis revealed a bulk conductivity of 2 x 10(-7) S. cm(-1) at room temperature and 1 x 10(-4) S. cm(-1) at 200 degrees C with a switch from extrinsic 1D to intrinsic 2D mechanism at 150. C. Li + diffusion coefficient was calculated to be in the order of 10(-12) cm(2). s(-1). More than 4 lithium (per f. u.) could be reversibly (de) inserted delivering capacity over 160 mAh/g with good cycling retention over 1000 cycles. With a feasible rapid synthesis, good diffusional and electrochemical behavior especially high rate capability, PbLi2Ti6O14 can act as a safe 1.35 V anode for rechargeable Li-ion batteries. (c) The Author(s) 2018. Published by ECS.

The efforts of Russian-Indian research team for application of the data science methods, in particular, artificial neural networks for development of the multi-factor computational models for studying effects of additive’s properties on the solid rocket propellants combustion are presented. The possibilities of the artificial neural networks (ANN) application in the generalisation of the connections between the variables of combustion experiments as well as in forecasting of “new experimental results” are demonstrated. The effect of particle size of catalyst, oxidizer surface area and kinetic parameters like activation energy and heat release on the final ballistic property of AP-HTPB based propellant composition has been modelled using ANN methods. The validated ANN models can predict many unexplored regimes, like pressures, particle sizes of oxidiser, for which experimental data are not available. Some of the regularly measured kinetic parameters extracted from non-combustion conditions could be related to properties at combustion conditions. Results predicted are within desirable limits accepted in combustion conditions.

P-type doping using Mg is essential for realizing a variety of electronic and optoelectronic III-nitride devices involving hetero-epitaxial thin films that also contain a significant number of dislocations. We report on the effect of Mg incorporation on dislocation and stress evolution during the growth of GaN thin films by using in situ curvature measurements and ex situ transmission electron microscopy. A complete picture involving the interplay between three effects—dopant size effect, dislocation bending, and polarity inversion—is presented. Mg aids dislocation bending, which in turn generates tensile stresses in Mg-doped GaN films. As a result, the compressive stress expected due to the dopant size difference effect can only be discerned clearly in films with dislocation densities below 5 × 109 cm−2. Polarity inversion at doping exceeding 1019 cm−3 is associated with a sharp drop in screw dislocation density. A kinetic stress evolution model has been developed to capture dislocation bending and size difference effects, and a match between calculated bending angle from the model and that measured from TEM images is obtained.P-type doping using Mg is essential for realizing a variety of electronic and optoelectronic III-nitride devices involving hetero-epitaxial thin films that also contain a significant number of dislocations. We report on the effect of Mg incorporation on dislocation and stress evolution during the growth of GaN thin films by using in situ curvature measurements and ex situ transmission electron microscopy. A complete picture involving the interplay between three effects—dopant size effect, dislocation bending, and polarity inversion—is presented. Mg aids dislocation bending, which in turn generates tensile stresses in Mg-doped GaN films. As a result, the compressive stress expected due to the dopant size difference effect can only be discerned clearly in films with dislocation densities below 5 × 109 cm−2. Polarity inversion at doping exceeding 1019 cm−3 is associated with a sharp drop in screw dislocation density. A kinetic stress evolution model has been developed to capture dislocation bending and size ...

Herein, we report the development of a unique architecture by chemically cross-linking salicylic acid (SA)-based poly(anhydride ester) onto a biodegradable amine-functionalized poly(caprolactone) (PCL), using lactic acid as a spacer. The ester and amide linkages in the SA PCL polymer, synthesized through melt condensation, were confirmed by NMR and FT-IR spectroscopic techniques. The enzymatic and nonenzymatic hydrolytic degradation profile exhibited linear degradation kinetics over an extended time period (>5 weeks). The compatibility and growth of C2C12 myoblast cells were found to be significantly improved on the fast-degrading SA PCL substrates compared to those over neat PCL and amine-functionalized PCL. Further, the decreased red blood cell damage, illustrated by 0.39% hemolysis activity and a minimal number of platelet adhesion on a SA PCL polymeric surface confirmed good hemocompatibility of the as-synthesized polymer. Together with a moderate bactericidal property, the spectrum of properties of this novel polymer can be attributed to the synergistic effect of the presence of chemical moieties of SA and amine groups in PCL. In summary, it is considered that a SA PCL-based cross-linked composite can be utilized as a new biodegradable polymer.

Narrow bandgap thermoelectric materials based on bismuth-telluride exhibit bipolar conduction that is detrimental to their overall thermoelectric performance. Through fabrication of composites of (Bi,Sb)(2)Te-3 matrix with embedded random colony of (Bi,Sb)(2)Te-3/Te lamellar (eutectic) with different length scales through a combination of different processing routes such as normal flame melting, cryomilling followed by spark plasma sintering and melt-spinning techniques followed by spark plasma sintering, interfacial charge defects and selective potential barrier were created leading to the injection of excess electron and activation of energy filtering effect of minority carriers. The selective-filtering of charge carriers lead to the delay in the onset of bipolar conduction to a higher temperature as a result of an increase in the band gap. This was found to be responsible for shifting the Peak ZT and the optimum operating regime of our alloys to a higher temperature. Changes in microstructure length scale from normal flame-melting to melt-spinning plus spark plasma sintering resulted in 20% reduction in the total thermal conductivity. (C) 2016 Elsevier B.V. All rights reserved.

Copper-tin (Cu-Sn) intermetallic alloy coating was developed on mild steel substrate by galvanostatic electrodeposition technique from sulfate-based acidic electrolyte containing Laprol as additive. The homogenous coating containing cubic 8 phase with composition of 32.6% Sn was obtained, when a current of -8.5 mA was made to flow through the electrochemical bath. The optimized coating with thickness of similar to 0.4-3 tm exhibits similar to 80% specular reflectance. The coating has a hardness of 2.6 GPa, suggesting a good scratch resistance property. The experimental results also suggest that the hydrophobic surface of Cu-32.6% Sn thin film can be potentially used as an attractive coating for solar reflector application under dusty and humid conditions. (C) 2016 Published by Elsevier Ltd.

The changes in structure, infrared absorption and magnetic property of nanocrystalline Mn0.5Zn0.5SmxFe2-xO4 (x = 0.01, 0.03 and 0.05) ceramics were studied after different doses (0, 15 and 25 kGy) of γ-irradiation. The samples were prepared by solution combustion route. We observed that up to the highest studied dose (25 kGy) of γ-irradiation all the samples retain the cubic spinel (Fd-3m) structure as of the pristine samples, however, the lattice parameter decreases. Furthermore, we observed the metastability of Sm (and Mn) atoms at the octahedral sites. By Sm3+ doping the saturation magnetization of the pristine samples decreases, but the magnetic coercivity increases drastically, indicating enhancement of magnetic anisotropy. After γ-irradiation the magnetic anisotropy vanishes completely and the sample behaves super-paramagnetically with a small variation in saturation magnetization. Our results are important to understand the behavior and stability of the magnetic hardness created by Sm3+ doping in soft magnetic Mn–Zn ferrite ceramics.

A number of experimental studies have established the critical role of electric field stimulation on cell functionality modulation of various cell types on a wide range of biomaterial platforms in vitro. In particular, cell fate processes, morphological changes and electroporation are significantly modulated over a narrow range of electric field stimulation conditions. Although a few studies using electrical network theory, first principle simulations and electrohydrodynamic models are reported in the literature, the present study establishes a theoretical foundation to a new perspective that bioelectric stress can significantly influence cell morphological changes/electroporation and in a broader sense, the cell response to electric field on biomaterial substrates. A single cell is modelled as a spherical membrane separating the culture medium and the cytoplasm having different dielectric properties. The analytical solutions to the Laplace equation and Poisson equation for the system are adopted to quantitatively capture the potential distribution in the cellular microenvironment for different cases. These include a cell on a conducting substrate, on an insulating substrate and a cell with surface charge density, in electric field stimulated cellular microenvironment. The biophysical significance of the normal stress distribution has been discussed in terms of the variation in the cellular deformation, depending on the frequency of the electric field and substrate conductivity. A significant difference has been observed in the deformation behavior at higher frequencies ( > 10 9 Hz) compared to low frequency and DC electric fields. This theoretical study therefore unravels the significance of substrate conductivity in synergy with electric field parameters to modulate cell response. In addition, the tangential component of the Maxwell stress tensor (shear stress), a measure of the stretching force on the membrane, has been used to obtain estimates of the critical electric field required for membrane rupture. It has been predicted that a cell with surface charge density requires electric fields of the order of 10 kV/mm in order to undergo membrane rupture, which is in line with the experimental observations reported in the literature. Taken together, the presented analysis is expected to provide guidelines to develop next generation biomaterials and biomedical devices for regenerative medicine and cancer treatments.

Steady shear response of a magnetorheological fluid (MRF) system containing porous mono-disperse magnetite (Fe3O4) spheres synthesized by solvothermal method is demonstrated. In applied magnetic field the interaction between the spherical particles leads to form strong columnar structures enhancing the yield strength and viscosity of the MRFs. The yield strengths of the MRFs also scale up with the concentration of magnetic particles in the fluid. Considering magnetic dipolar interaction between the particles the magneto-mechanical response of the MRFs is explained. Unlike metallic iron particles, the low-density corrosion resistant soft-ferrimagnetic Fe3O4 spherical particles make our studied MRF system efficient and reliable for shock-mitigation/vibration-isolation applications. (C) 2018 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.

It has been reported that defect density in ball-milled graphite lattice increases with the milling time. Guided by this, we hypothesized that the oxygen content of graphene oxide can be substantially enhanced by oxidizing ball-milled graphite and also, the oxygen content would monotonically increase with the milling time as the defect sites would be preferred sites for oxidation. Interestingly, we observed that this correlation was not directly proportional for all milling hours. Even though, the defect density of graphite monotonically increased with milling time, the oxygen content of graphene oxide initially increased and then decreased. This was due to milling time dependent change in the size of the graphite plates and consequent relative abundance of the different oxygen containing functional groups on graphene oxide (GO) produced from the milled graphite.

Magnetically soft nickel-zinc ferrite (Ni0.5Zn0.5Fe2O4) powder with high saturation magnetization was synthesized by solution combustion route using metal nitrates as precursors and glycine as fuel. The particles were found to have irregular morphology. Three different concentrations of magnetorheological fluids (MRFs) were prepared by dispersing 10, 20 and 40 wt% of these particles in thin silicone oil. The behaviours of the MRFs were studied under steady shear conditions at different applied magnetic field strengths (B). The yield strength (tau(Y)) and viscosity (eta) of all the MRFs were found to increase with B and particle fill fraction phi, while the response of the MRFs was strongly influenced by the morphology, microstructure and saturation magnetization of the particles. Owing to the low density of the particles, the observed off-state viscosity is high. However, the excellent thermo-oxidative and chemical stabilities of these magnetic oxide particles than metallic magnetic particles make these MRFs dependable for applications in harsh working environments. In addition, the low cost and feasibility of large scale preparation of these magnetic oxides make these MRFs further attractive for industrial applications. (C) 2018 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.

A buried channel normally-off AlGaN/GaN MOS-HEMT with gate recess etching is reported. The buried channel operation is achieved by in situ doping of GaN to introduce a p-n junction in the GaN buffer. The fabricated buried channel MOS-HEMT with 12.5 nm atomic layer deposition (ALD) Al2O3 gate dielectric featured a threshold voltage of 1.3 V with a drain saturation current of 287 mA mm(-1) for a device with 3.5 mu m long gate length and 11 mu m sourcedrain spacing. The field effect mobility improved from 25 cm(2)/Vs for a reference device to 142 cm(2)/Vs for the buried channel device. Due to the presence of the p-n junction depletion region in the GaN buffer, the leakage in the off state decreased by about 4 orders of magnitude (4 nA mm(-1) compared to 76 uA mm(-1) for the reference device). The buried channel device also gives better breakdown characteristics, with a breakdown voltage of 158 V compared to 98 V for the reference device.

We report the magnetic field and particle-concentration dependent steady-state shear-responses of rod shaped Li-Zn ferrite particle based magnetorheological fluids (MRFs). Rod-shaped soft ferrimagnetic Li-Zn ferrite (Li0.4Zn0.2Fe2.4O4) particles were synthesized using the combustion synthesis method. MRFs of three different particle-concentrations (phi = 0.1, 0.2 and 0.4, in weight fraction) were prepared using silicone oil. Their yield strength and dynamic viscosity were studied at different applied magnetic fields (B). With an increase in B and phi, the yield strength ((Y)) of the MRFs increases. This behaviour is assigned to the formation of stronger columnar structures of the magnetically interacting particles which resist the flow (shear) of the MRF. For the MRF with phi = 0.4 and B = 1.2 T, we observed a maximum (Y) value of approximate to 1.25 kPa. Furthermore, we observed that, based on the on-state to off-state viscosity ratio ((on)/(off)) at a particular operating B value, the optimum particle concentration required for energy- and cost-efficient operation of the MRFs can be chosen. The absence of a stabilizing-agent or de-agglomerating-coating, the low density, and the excellent oxidation- and corrosion-resistance of the soft ferrimagnetic rod-shaped Li-Zn ferrite particles make this MRF-system highly versatile and economical for many magneto-mechanical applications.

Nonpolar a-plane GaN epitaxial films were grown on an r-plane sapphire using the plasma-assisted molecular beam epitaxy system, with various nitrogen plasma power conditions. The crystallinity of the films was characterized by high-resolution Xray diffraction and reciprocal space mapping. Using the X-ray ``rocking curve-phi scan'', 0002],1-100], and 1-102] azimuth angles were identified, and interdigitated electrodes along these directions were fabricated to evaluate the direction-dependent UV photoresponses. UV responsivity (R) and internal gain (G) were found to be dependent on the azimuth angle and in the order of 0002] > 1-102] > 1-100], which has been attributed to the enhanced crystallinity and lowest defect density along 0002] azimuth. The temporal response was very stable irrespective of growth conditions and azimuth angles. Importantly, response time, responsivity, and internal gain were 210 ms, 1.88 A W-1, and 648.9%, respectively, even at a bias as low as 1 V. The results were validated using the Silvaco Atlas device simulator, and experimental observations were consistent with simulated results. Overall, the photoresponse is dependent on azimuth angles and requires further optimization, especially for materials with in-plane crystal anisotropy.

EMI shielding properties of nanocomposite containing lead hexaferrite (PFO) and polyaniline (PANI), a conducting polymer, was studied in X and K-u band frequencies. The nanocomposite shows enhanced EMI shielding properties than that of the pure PANI. Incorporation of PFO particles in the PANI enhances the total shielding effectiveness (SET) up to -24 dB at 18 GHz. This means that these nanocomposites can shield similar to 99% of the incoming EM radiation. The PFO/PANI shows much higher attenuation constant values over the measured frequency range. By adding the PFO in the PANI we have created more interfaces between Wax-PFO,Wax-PANI, PANI-PFO and PFO-PANI. These enhanced interfaces lead to Maxwell-Wagner polarization which results in a higher dielectric loss than only PANI.

Tin oxide (SnO2) nanowires are synthesized by Au catalyzed chemical vapor deposition of Sn and C mixture at 900 degrees C by employing a continuous flow of Ar: O-2 (10:1) for an hour. X-ray diffraction and Raman spectroscopy studies indicate that the as-grown SnO2 nanowires are crystalline in nature with tetragonal rutile phase. Electron microscopy studies reveal towards high aspect ratio of nanowires. The field emission studies show that SnO2 nanowires grown on Si substrate exhibit low turn-on field of 1.75 V/mu m (at 0.1 mu A/cm(2)) and long-term emission stability over a period of more than 50 h with a current density of 4 mu A/cm(2) at a constant electric field of 2.25 V/mu m. Hardly any considerable degradation in the emission current is noticed even after 50 h which may be attributed to the high crystallinity of SnO2 nanowires. (C) 2015 Elsevier B.V. All rights reserved.

Ultrathin Au nanowires (similar to 2 nm diameter) are interesting from a fundamental point of view to study structure and electronic transport and also hold promise in the field of nanoelectronics, particularly for sensing applications. Device fabrication by direct growth on various substrates has been useful in demonstrating some of the potential applications. However, the realization of practical devices requires device fabrication strategies that are fast, inexpensive, and efficient. Herein, we demonstrate directed assembly of ultrathin Au nanowires over large areas across electrodes using ac dielectrophoresis with a mechanistic understanding of the process. On the basis of the voltage and frequency, the wires either align in between or across the contact pads. We exploit this assembly to produce an array of contacting wires for statistical estimation of electrical transport with important implications for future nanoelectronic/sensor applications.

An efficient buffer layer scheme has been designed to address the issue of curvature management during metalorganic chemical vapour deposition growth of GaN on Si (111) substrate. This is necessary to prevent cracking of the grown layer during post-growth cooling down from growth temperature to room temperature and to achieve an allowable bow (

Combining oblique angle deposition with standard graphene transfer protocols, two planar arrays of metal nanoparticles are fabricated that are vertically separated by atomic dimensions, corresponding precisely to the thickness of a single layer of graphene, i.e., 0.34 nm. Upon illumination of light at an appropriate wavelength, the local electromagnetic field at the junction of the dimers can be increased dramatically, thereby resulting in the most sensitive graphene-plasmonic hybrid photodetector reported to date.

This study explores the effect of Pt and TiO2 dispersion on the catalytic activity and analyzes the kinetics of CO oxidation over a novel catalyst consisting of ultrafine Pt-particles decorated on GO-supported TiO2. Its catalytic activity is compared with catalysts synthesized by decorating Pt nanoparticles on (i) TiO2 (Aeroxide, P25), and TiO2 prepared by using (ii) sol-gel (TiO2-SG) and (iii) microwave techniques (TiO2-MW). A 99.9% conversion of CO to CO2 is observed at 150 degrees C on Pt-TiO2-GO, while it occurs at significantly higher temperatures over other catalysts. Detailed characterization of the catalysts using XRD, TEM, TGA, ICP-MS and BET suggests that this enhanced catalytic activity is because of the uniform dispersion of Pt-TiO2 nanoparticles on the high surface area GO sheets. A combination of DRIFTS and CO-TPD is used to develop a catalytic reaction pathway and is supported by a kinetic model. This study establishes that ensuring a uniform support and noble metal dispersion can be used to develop highly active catalysts. (C) 2017 Elsevier B.V. All rights reserved.

The ultrathin channel in 2D semiconductors, although playing host to several interesting properties, also renders strong interactions (scattering) of charge carriers with the surrounding medium. The over-arching dominance of surface (interfacial) optical phonons in 2D charge transport and engineering ideal nitride-based dielectric environments for large performance gains is reported. Charge transport in MoS2 field effect transistors (FETs) fabricated on three conventional substrates, SiO2, Al2O3, and HfO2, is contrasted with a newly introduced, CMOS-compatible nitride-based dielectric: aluminum nitride (AlN) by employing semi-classical models which account for charged impurity, surface optical phonon, and intrinsic phonon scattering. Unlike previous reports focused on charge impurity scattering, this work presents a new paradigm of utilizing high optical phonon energies intrinsic to ``stiff `` nitride bonds. This results in substantially lower surface optical phonon scattering in 2D FETs which directly influences peak field effect (FE) mobility, high field mobility degradation, and temperature-dependent mobility. Leveraging on these insights, high-performance sulfur-passivated MoS2 FETs with an optimum all-nitride environment (hexagonal boron nitride/MoS2/AlN) are demonstrated with FE mobility up to 72.8 cm(2) V-1 s(-1). This work is envisioned to address important issues in design of dielectric environments for a host of applications based on 2D materials.

Full solar spectrum absorbers are widely pursued for applications related to photocatalysis and photovoltaics. Here we report multivalent Cu-doped ZnO nanoparticles which exhibit full solar spectrum absorbance and high photoactivity. Metathesis-based, green-chemical approaches with synthesis yield of similar to 100% are used. Cu incorporation in ZnO results in an increase of average solar spectrum absorbance from a mere 0.4% to 34%. On the other hand, (Zn, Cu)0 composites result in materials with up to 64% average solar spectrum absorbance. Doped systems operate well under both visible and UV illumination. The nanomaterials prepared are characterized by using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) surface area analysis, and X-ray photoelectron spectroscopy (XPS). Photocatalysts explored have particle sizes >= 50 nm. This is deliberately done in order to avoid the nanotoxic size regime of ZnO. Despite the large particle size and low specific surface area (

Protein functional annotation relies on the identification of accurate relationships, sequence divergence being a key factor. This is especially evident when distant protein relationships are demonstrated only with three-dimensional structures. To address this challenge, we describe a computational approach to purposefully bridge gaps between related protein families through directed design of protein-like ``linker'' sequences. For this, we represented SCOP domain families, integrated with sequence homologues, as multiple profiles and performed HMM-HMM alignments between related domain families. Where convincing alignments were achieved, we applied a roulette wheel-based method to design 3,611,010 protein-like sequences corresponding to 374 SCOP folds. To analyze their ability to link proteins in homology searches, we used 3024 queries to search two databases, one containing only natural sequences and another one additionally containing designed sequences. Our results showed that augmented database searches showed up to 30% improvement in fold coverage for over 74% of the folds, with 52 folds achieving all theoretically possible connections. Although sequences could not be designed between some families, the availability of designed sequences between other families within the fold established the sequence continuum to demonstrate 373 difficult relationships. Ultimately, as a practical and realistic extension, we demonstrate that such protein-like sequences can be ``plugged-into'' routine and generic sequence database searches to empower not only remote homology detection but also fold recognition. Our richly statistically supported findings show that complementary searches in both databases will increase the effectiveness of sequence-based searches in recognizing all homologues sharing a common fold. (C) 2013 Elsevier Ltd. All rights reserved.