Fabrication of Large‐Scale Hierarchical ZnO Hollow Spheroids for Hydrophobicity and Photocatalysis

We report here the preparation of a crystalline, pure hexagonal phase of ZnO as hollow 500–800 nm spheroids in the presence of organic bases, such as pyridine, using zinc acetate as the precursor salt. The spheroids exhibit unique 3D hierarchical architectures, like cocoons, and demonstrate improved superhydrophobic (water contact angle, 150°) character due to the inherited air‐trapped capillarity within the cocoon structure. The simple synthetic strategy used in this process is modified hydrothermolysis (MHT), which represents a general approach and may contribute to the formation mechanism of the hollow nanostructures with highly improved porosity. Depending on the concentration of the precursor salt, it has been possible to cover glass plates or the inner wall of a reaction vessel with ZnO nanocrystals. A low salt concentration (<0.01 M ) allows the easy preparation of a superhydrophobic glass surface, whereas a high salt concentration (>0.01 M ) results in the precipitation of cocoons at the bottom of the reaction vessel as a solid mass together with a deposited thin film of ZnO nanocrystals covering the inner wall of the glass vessel. The thickness of the film successively grows through repetitive hydrothermolysis processes for which a low salt concentration (<0.01 M ) was employed. Because of the hollow cocoonlike morphology, the surface area of the film is greatly increased, which makes it accessible for functionalization by incoming substrates from both sides (internally and externally) and helps to drive a competent photocatalytic dye degradation pathway. The heterocyclic base pyridine exclusively develops cocoons. Thus, the mechanism of self‐aggregation of ZnO nanocrystals under MHT reaction conditions has been studied and the characterization of the compounds has been supported with physical measurements.     

Shelf-life extension of convenience meat products sold in Indian supermarkets by radiation processing

A variety of ready-to-cook meat products available in Indian supermarkets (mutton mince, chicken mince, chicken chunks, and chicken legs) were studied. The samples were irradiated (2.5 kGy), or left untreated as control, and stored at 0–3 °C for up to 21 days. The effect of irradiation on the microbiological, chemical, and sensory properties was evaluated at intervals during the storage period. Irradiated samples had a longer shelf-life at 0–3 °C compared with the corresponding non-irradiated samples. Fecal coliforms were eliminated by irradiation treatment. Radiation processed samples had lower counts of Staphylococcus spp. There were no significant organoleptic changes in irradiated samples stored at chilled temperatures.     

Failure in anisotropic nonwoven materials at finite deformation

The current work proposes a finite deformation strong discontinuity approach based modeling of failure in anisotropic materials with reorientation based micromechanical network model for the bulk response. These materials consist of randomly cross-linked one dimensional filaments at their microstructure which undergo non-affine deformation as well as reorientation upon loading before undergoing complete failure. The computationally efficient strong discontinuity approach allows to capture the failure kinematics by introducing a local problem where a strong discontinuity exists, thereby leading to an enhanced deformation gradient. A precise evaluation of the bulk response is done by homogenizing the physical microscopic response of constituent filaments where reorientation is introduced with an initial straightening effect of fiber undulations. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

An algorithm for single-item economic lot-sizing problem with general inventory cost, non-decreasing capacity, and non-increasing setup and production cost

This paper considers an economic lot-sizing model with non-decreasing capacity constraint, non-increasing setup cost and production cost, and a general inventory cost. We prove that when periodic starting inventory is not less than a certain critical value, it is optimal to produce nothing; this critical value can be computed easily which results in a new effective algorithm.     

Effect of nanoscale diamondoids on the thermomechanical and morphological behaviors of polypropylene and polycarbonate

Nanoscale MolecularDiamond products (various diamondoid materials), obtained from petrochemical feedstocks, have been investigated as additives for polypropylene and polycarbonate. Three of the homologues of this family (diamantane, triamantane, and the [121]tetramantane isomer) have marginal effects on the thermal and mechanical properties of nonpolar/semicrystalline polypropylene. Mixtures of methylated tetramantane nanofillers also increase the stress–strain behavior of polypropylene composites without significantly impacting their glass transition temperatures. The addition of the selected diamondoids to amorphous/moderately polar polycarbonate increases the polymer tensile modulus significantly with marginal increases in the yield stress. The effects of the selected diamondoids on the thermal stability, crystallinity, and optical properties of polypropylene and polycarbonate are also reported. The results for the mechanical properties show that the selected diamondoids behave as plasticizers in polypropylene, whereas in polycarbonate, they act as antiplasticizers without adversely affecting the optical clarity. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1077–1089, 2007     

Performing chemical reactions in virtual capillary of surface tension-confined microfluidic devices

In this paper we report a new method of fabrication of surface tensionconfined microfluidic devices on glass. We have also successfully carried out some well-known chemical reactions in these fluidic channels to demonstrate the usefulness of these wall-less microchannels. The confined flow path of liquid was achieved on the basis of extreme differences in hydrophobic and hydrophilic characters of the surface. The flow paths were fabricated by making parallel lines using permanent marker pen ink or other polymer on glass surfaces. Two mirror image patterned glass plates were then sandwiched one on top of the other, separated by a thin gap-created using a spacer. The aqueous liquid moves between the surfaces by capillary forces, confined to the hydrophilic areas without wetting the hydrophobic lines, achieving liquid confinement without physical side-walls. We have shown that the microfluidic devices designed in such a way can be very useful due to their simplicity and low fabrication cost. More importantly, we have also demonstrated that the minimum requirement of such a working device is a hydrophilic line surrounded by hydrophobic environment, two walls of which are constituted of air and the rest is made of a hydrophobic surface.     

Palladium(II)‐Catalyzed meta‐CH Olefination: Constructing Multisubstituted Arenes through Homo‐Diolefination and Sequential Hetero‐Diolefination

Divinylbenzene derivatives represent an important class of molecular building blocks in organic chemistry and materials science. Reported herein is the palladium‐catalyzed synthesis of divinylbenzenes by meta‐C? H olefination of sulfone‐based arenes. Successful sequential olefinations in a position‐selective manner provided a novel route for the synthesis of hetero‐dialkenylated products, which are difficult to access using conventional methods. Additionally, 1,3,5‐trialkenylated compounds can be generated upon successful removal of the directing group.     

A new prenylated biflavonoid from the leaves of Garcinia dulcis

A new prenylated biflavonoid, named dulcisbiflavonoid A, together with five biflavonoids were isolated from the leaves of Garcinia dulcis. Their structures were elucidated by analysing their spectroscopic data, especially 1D and 2D NMR.     

Bacilli as Biological Nano-factories Intended for Synthesis of Silver Nanoparticles and Its Application in Human Welfare

The search of eco-friendly technologies for nano-synthesis is significant to expand their applications in human welfare. Nowadays, various inorganic nanoparticles with beneficial features have been synthesized via physical, chemical, and biological means. Significant biological applications of silver nanoparticles include on-infectious microbes, target drug delivery, cancer and vector-borne disease control. Their syntheses have been tested from plant fungi, bacteria, and viruses. The bacterial mediated synthesis of silver, gold, zinc and other metal leads to a milestone in nano-medicines. Thus, in this review, we focus on the contribution of Bacilli in the synthesis of silver nanoparticles, the mechanism of action and their potential application in the welfare of human beings.