Synthesis of Nanocrystalline Alumina Using Egg White

A new simplified route to prepare nanocrystalline alumina powders is proposed. The method involved the use of freshly extracted egg white (ovalbumin) and aluminum nitrate in an aqueous medium. Changes in ionic strength upon addition of aluminum nitrate resulted in gelation of ovalbumin. The added metal ions were dispersed in the gelled ovalbumin matrix. Heat treatment of the gelled mass resulted in nanosized γ alumina at as low a temperature as 330°C. TEM analysis showed that the particle size ranged from 15 to 80 nm.     

Shape forming of ceramics via gelcasting of aqueous particulate slurries

Gelcasting is a promising technique for shape forming of bulk dense or porous ceramic, metal structures. The process offers a number of advantages over processes such as slip casting, injection molding in forming complex ceramic shapes. It is shown here that the optimization of slurry rheology, choice of mold material, mold design and the drying conditions have a significant role in the overall success of the process. In this process, components of simple or complex shapes can be produced to near net shape by direct casting. If required complex shapes can also be produced by machining the green gelcast bodies. The process of gelcasting also has a lot of potential in forming highly porous ceramic shapes.     

Comparative inhibitory properties of some Indian medicinal plant extracts against photosensitization-induced lipid damage

The protective activities of Emblica officinalis, Terminalia bellerica and Terminalia chebula ethanol extracts against photosensitization-induced oxidation of rat liver mitochondrial lipid were assessed. All the extracts could effectively prevent lipid peroxidation, as assessed by measuring thiobarbituric acid-reactive substrates, lipid hydroperoxide, conjugated diene and 4-hydroxynonenal. The E. officinalis extract was the most potent, revealing its superior ability to scavenge ¹O₂. The extracts also afforded excellent protection against iron-mediated lipid peroxidation that might also be useful in reducing photo-induced iron toxicity. The activities of the extracts were primarily due to their constituent phenolics.     

Multiple-fluorophore-specie detection with a tapered Fabry-Perot fluorescence spectrometer

A novel fluorescence spectrometer and method for the simultaneous detection of multiple-fluorophore species in a no-moving-parts, instantaneous manner is described. In the reported embodiment of the instrument, a tapered Fabry-Perot filter is used to spatially encode the fluorescence spectrum from a multiple-dye-containing test sample. Using a pseudoinverse reconstruction algorithm, we spectrally decode the particle concentration for each dye specie in the test sample. Experimental results are reported along with a theoretical treatment of the method.     

Dithieno[3,2‐b:2′,3′‐d]pyrrol‐Cored Hole Transport Material Enabling Over 21% Efficiency Dopant‐Free Perovskite Solar Cells

Dopant‐free hole transport materials (HTMs) are essential for commercialization of perovskite solar cells (PSCs). However, power conversion efficiencies (PCEs) of the state‐of‐the‐art PSCs with small molecule dopant‐free HTMs are below 20%. Herein, a simple dithieno[3,2‐b:2′,3′‐d]pyrrol‐cored small molecule, DTP‐C6Th, is reported as a promising dopant‐free HTM. Compared with commonly used spiro‐OMeTAD, DTP‐C6Th exhibits a similar energy level, a better hole mobility of 4.18 × 10^?4 cm² V^?1 s^?1, and more efficient hole extraction, enabling efficient and stable PSCs with a dopant‐free HTM. With the addition of an ultrathin poly(methyl methacrylate) passivation layer and properly tuning the composition of the perovskite absorber layer, a champion PCE of 21.04% is achieved, which is the highest value for small molecule dopant‐free HTM based PSCs to date. Additionally, PSCs using the DTP‐C6Th HTM exhibit significantly improved long‐term stability compared with the conventional cells with the metal additive doped spiro‐OMeTAD HTM. Therefore, this work provides a new candidate and effective device engineering strategy for achieving high PCEs with dopant‐free HTMs.     

Homogeneous and polymorphic transformations to ordered intermetallics in nanostructured Au–Cu multilayer thin films

Journal of Materials Science - Atomic arrangements in the nanostructured grains and interfaces of thermally evaporated Au/Cu multilayer thin films on polycrystalline Si substrate have been explored...     

An image encryption scheme using sequence generated by interval bisection of polynomial function

Multimedia Tools and Applications - Chaos based image encryption techniques are well accepted in research communities to perform permutation at pixel/bit level using pseudo-random sequence and...     

Preorder-based triangle: a modified version of bilattice-based triangle for belief revision in nonmonotonic reasoning

Bilattice-based triangle provides an elegant algebraic structure for reasoning with vague and uncertain information. But the truth and knowledge ordering of intervals in bilattice-based triangle cannot handle repetitive belief revisions which is an essential characteristic of nonmonotonic reasoning. Moreover, the ordering induced over the intervals by the bilattice-based triangle is not sometimes intuitive. In this work, we construct an alternative algebraic structure, namely preorder-based triangle and we formulate proper logical connectives for this. It is also demonstrated that Preorder-based triangle serves to be a better alternative to the bilattice-based triangle for reasoning in application areas, that involve nonmonotonic fuzzy reasoning with uncertain information.     

A blind audio watermarking based on singular value decomposition and quantization

International Journal of Speech Technology - In this work, we have proposed a robust audio watermarking technique in which a binary image is embedded into a host audio signal for copyright...     

Selective greedy routing: exploring the path diversity in backbone mesh networks

This paper proposes a new routing protocol for IEEE 802.11s wireless mesh network to overcome the problems associated with the conventional proactive and reactive routing approaches. The proposed ‘Selective Greedy’ (SelG) routing protocol operates in two phases. In the first phase it exploits the proactive mode of Hybrid Wireless Mesh Protocol, the standard routing protocol for IEEE 802.11s mesh, and constructs a set of potential forwarders for every mesh point, that can act as the next-hop relay. In the second phase, during the actual data communication, a candidate is selected from the set of potential forwarders based on a local optimization. The optimization procedure considers the statistical effect of local link quality fluctuation and interference over the global routing path selection. This way the SelG protocol reduces the control packet flooding in the network (a major drawback for reactive protocols). At the same time, the optimization procedure captures the network dynamics, and thus avoids the possibility of routing based on stale information (a drawback for proactive protocols). The routing properties and the correctness of the SelG protocol is established theoretically, and the performance of the protocol is analyzed through simulation results. The proposed protocol is implemented in an indoor wireless mesh testbed, and the performance is evaluated and compared with other traditional approaches.