Polynorbornene/fluorosilica hybrids for hydrophobic and oleophobic coatings

Polynorbornene dicarboxylic anhydride (PNA)/fluorosilica hybrid coating materials with good hydrophobicity, oleophobicity, transparency, thermal stability, and hardness were synthesised using a sol–gel method. The surface structure, transparency, hydrophobicity, oleophobicity, and surface free energy of the coating could be controlled by adjusting the fluorosilane ratio. The maximum static water and oil contact angles of films were 112° and 87°, respectively. The PNA/fluorosilica hybrid films exhibited good transparency and colourlessness. The marks written using water and oil-based pens on the films could be erased with a tissue even after eight times. In addition, the hardness of the hybrid films was enhanced to 4H with increasing fluorosilane content.     

Simple synthesis of ZnS nanoparticles in alkaline medium

ZnS nanoparticles were successfully synthesized by reflux under an alkaline medium. The nanoparticles were characterized by using X-Ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The optical properties of ZnS nanoparticles were examined by photoluminescence (PL) spectrum. The result shows that the as-synthesized ZnS nanoparticles had a cubic phase. SEM image shows that ZnS nanoparticles are basically in spherical shape and are homogeneous. The particle size was found to be in the range of 18 nm.     

Electronic conduction mechanism in chitin–polyaniline blend

The electrical conductivity of chitin–polyaniline blend doped with HCl has been studied in the temperature range 323–373 K for various blend compositions. Conductivity of blends increases from less than ≈10^?7 S/cm to 2.15 × 10^?5 S/cm, depending on the percentage of polyaniline in the blend due to self-doping of LiCl. When these blends are doped with HCl conductivity raises to ≈9.68 × 10^?2 S/cm. Current–voltage data is analyzed using various models available. The results suggest Schottky–Richardson and one-dimensional variable range hopping mechanisms for undoped blend and one-dimensional variable range hopping mechanism in the case of doped blend.     

Evaluation of connection flexibility in cold formed steel racks

Steel storage racks are three-dimensional framed structures fabricated from cold formed steel sections, wherein hook-in end connectors are used to make beam-column connections which are basically boltless and semi-rigid in nature. Different types of beam end connectors with different geometry of the connected members are available, making it impossible to develop a generalized analytical model. Only very few theoretical models are available to evaluate the performance of the joints for some typical connectors. More often experimental evaluation and numerical studies are needed to predict the behaviour of every different type of connectors. In the present study eighteen experiments were conducted on a commercially available pallet rack connection by varying the most influencing parameters such as thickness of the column, depth of the connector and the depth of the beam. The main objective of this work is to quantify the beam to column joint, flexibility of commonly used pallet rack frame and to develop a general Frye-Morris type/three parameter power model type moment versus relative rotation relationship. A companion finite element shell model that simulates the experimental behaviour closely is developed using ABAQUS finite element software, which is also used for further parametric studies. Using the three major variables as size parameters, a Frye-Morris type of equation has been proposed. Some calibration studies have also been carried out. Using the ultimate moment capacity, initial connection stiffness and the shape parameter obtained, a three parameter power model has also been proposed to represent the moment-rotation behaviour of the boltless connections.     

Hydrogen Generation from CO2 Reforming of Biomass-Derived Methanol on Ni/SiO2 Catalyst

Topics in Catalysis - CO2 reforming of methanol for producing hydrogen was experimentally carried out in a fixed-bed reactor on 10%Ni/SiO2. The 10%Ni/SiO2 was completely reduced during H2...     

Effect of silane functionalized alumina on poly(vinyl butyral) nanocomposite films: Thermal,mechanical, and moisture barrier studies

In this work, a hybrid‐polymer nanocomposite film, based on polyvinyl butyral/amino‐silane functionalized nano alumina, was fabricated by melt processing. The calcium degradation measurements suggest the functionalized nanocomposite films exhibit higher resistance towards moisture penetration as compared to the neat alumina loaded films. Thermal stability, mechanical strength, and contact angle studies of the composites were also conducted to evaluate the performance of the functionalized alumina loaded films. These nanocomposite films were encapsulated over Al/P3HT/ITO Schottky structured device. The changes observed in the current density of the devices to the applied voltage before and after accelerated aging conditions are presented. The nanocomposite with functionalized alumina films exhibits 50% change in current density, which is superior to that attained with neat and non‐functionalized films. POLYM. COMPOS., 35:1426–1435, 2014. © 2013 Society of Plastics Engineers     

Natural convection in an enclosure with a localized nonuniform heat source on the bottom wall

Natural convection in an air filled enclosure with a localized nonuniform heat source mounted centrally on the bottom wall is numerically investigated. The vertical walls are cooled while the top wall and the remaining portions of the bottom wall are insulated. The heat source is assumed to be isothermal with a linearly varying temperature. The governing equations were solved using finite volume method on a uniformly staggered grid system. The computational results are presented in the form of isotherm and streamline plots and Nusselt numbers. The effects of the source nonuniformity parameter, λ and the line source length, ε are investigated for the Grashof numbers Gr = 10⁶ and 10⁷. It is found that for Gr = 10⁶ nonuniform heating of the line source enhances the overall heat transfer rate markedly compared to uniform heating of the heat source whereas for Gr = 10⁷ its effect is marginal.     

Failure analysis of cast-on-strap in lead-acid battery subjected to vibration

Lead-acid batteries (LAB) are widely used in transportation sector for starting, lighting and ignition application. The possibility of vibration mode of failure occurs in this application due to wear and tear of the road. These vibration causes fatigue failure, particularly between the cast on strap and pillar post leading to loss of electrical connection. In this paper vibration test is conducted on a 12 V/75 Ah AGM Valve Regulated Lead-Acid Battery (VRLAB) used for above mentioned application in India. The test is carried out using Electrodynamic Vibration System model SD-10-240/GT500M/DA-10. The shaker is performed with a sinusoidal excitation, with an acceleration of 2.143G and a fixed frequency of 16.7 Hz. The peak to peak displacement is 4 mm. The deformation and crack propagation features on the surface and cross sectional area of pillar post and strap in both positive and negative group are observed with Scanning Electron Microscope (SEM). The material is yielded due to improper fusion between pillar post and strap which could not stand the vibration force. During vibration this region is vulnerable for fatigue failure.     

Modularization of a Large-Scale Business Application: A Case Study

Large software systems, developed over several years, are the backbone of industries such as banking, retail, transportation, and telecommunications. With multiple bug fixes and feature enhancements, these systems gradually deviate from the intended architecture and deteriorate into unmanageable monoliths. This article presents a case study of a banking application besot with such problems and the modularization approach that the company adopted as a solution. It also highlights benefits unearthed as a result of this reengineering exercise.