Structural and optical investigation of sputter deposited hydrophobic chromium oxynitride films

Nanocrystalline chromium oxynitride films were deposited by reactive RF magnetron sputtering of metallic chromium target in argon and helium atmospheres. The paper deals with consequence of increase in oxygen partial pressure on structural, hydrophobic and optical properties of chromium oxynitride films. The film stoichiometry changes from CrN and Cr₂O₃ to only Cr₂O₃ with increase in oxygen partial pressure as evident from X-Ray Diffraction analysis in both cases. The average crystallite size decreases with increase in oxygen partial pressure for both gas atmospheres. The thickness calculated from transmission data and surface profilometer are in good harmony with each other. The deposited films are hydrophobic by nature and the contact angle of the films varies as a function of surface roughness. Surface energy of the films is inversely proportional to the observed contact angle values. As oxygen partial pressure increases, the optical properties: transmission and band gap values increases as determined by Ultraviolet-visible-Near Infrared spectrophotometer in both cases. This film can have potential applications as insulating, hydrophobic and corrosion resistant protective coatings.     

Silicon Lens Optimization to Create Diffuse,Uniform Illumination from Incoherent THz Source Arrays

Journal of Infrared, Millimeter, and Terahertz Waves - Arrays of terahertz (THz) sources provide a pathway to overcoming the radiation power limitations of single sources. Several independent...     

Finite abstractions for hybrid systems with stable continuous dynamics

This paper outlines an abstraction process in which a particular class of hybrid automata with continuous dynamics that have parameterized positive limit sets, are being abstracted into finite transition systems. The limit sets with their corresponding attraction regions define pre- and post-conditions for the continuous dynamics, and determine the transitions in the discrete abstraction. An observable (weak) bisimulation equivalence is established between the two models. The abstraction process described can find application in verification, as well as in planning and symbolic control.     

Proxy re-encryption architect for storing and sharing of cloud contents

Internet-based online cloud services provide enormous volumes of storage space, tailor-made computing resources and eradicate the obligation of native machines for data maintenance as well. Cloud storage service providers claim to offer the ability of secure and elastic data-storage services that can adapt to various storage necessities. Most of the security tools have a finite rate of failure, and intrusion comes with more complex and sophisticated techniques; the security failure rates are skyrocketing. Once we upload our data into the cloud, we lose control of our data, which certainly carries new security hazards toward integrity and privacy of our information. In this paper, we discuss a secure file sharing mechanism for the cloud with proxy re-encryption (PRE). PRE-scheme is implemented with the Disintegration Protocol to secure storage data in storage and in the flight. The paper introduces a new contribution of a seamless file sharing technique among different clouds without sharing an encryption key.     

Structural,morphological, and optical properties of strontium doped lead-free BCZT ceramics

We report the synthesis of Sr²⁺ doped Ba_0.9-xCa_0.1Sr_xTi_0.8Zr_0.2O₃ nano-ceramics by the conventional solid-state reaction method. Phase formation of single-phase orthorhombic ABO₃ type structure with space group P2mm was confirmed through X-ray diffraction (XRD). The crystallite size increased with increasing doping concentration from 25.46 nm to 52.96 nm as calculated by the Scherrer formula and from 47.1 nm to 88.5 nm by the Williamson-Hall method. The lattice parameter, dislocation density, and apparent density decreased with doping, except for when x = 0.05. The porosity was found to increase up to 16.8% with increasing doping. Field emission scanning electron microscopy (FESEM) shows that samples exhibit a flake-like structure. X-ray photoelectron spectroscopy (XPS) analysis confirms that Sr-ions occupy the Ca-site, for x = 0.05, and force the Ca ions to occupy the Ti-sites. For the higher concentration of Sr, i.e. x ≥ 0.15, no more forced substitution is observed and Sr-ions occupy the Ba-site only, which decreases oxygen vacancies. Diffused rings observed in selective area electron diffraction (SAED) patterns indicate the high crystalline order of the samples. The Fourier-transformed infrared spectroscopy (FTIR) measurements show a single broad peak between 544 and 594 cm^?1 for all the compositions, while two prominent peaks are observed for the composition x = 0.05 at 528 cm^?1 and 592 cm^?1. The Raman spectra show a shift in the most prominent peak, observed approximately 517 cm^?1.     

An investigation of molybdenum surface reinforcement on the hardness and wear properties of AISI 630

AISI 630 stainless steel (SS) surface has been reinforced with molybdenum (Mo) using gas tungsten arc (GTA) as a heat source. The optimum GTA heat source conditions have been finalised based on the proper fusion of base metal. The microhardness of the Mo-reinforced AISI 630 SS was found to be 502?HV which shows an improvement of 35% with respect to the base metal (371?HV). To improve the properties, the reinforced alloy was heat treated. The microhardness of the reinforced and aged AISI 630 was 725?HV, which was higher than the base metal by 95%. Dry sliding wear tests using a Pin-on-Disc machine were performed and it was found that the wear resistance of the reinforced surface was improved by 52% with respect to base metal. Characterisation techniques such as optical microscopy, scanning electron microscope, energy-dispersive X-ray spectrometry and XRD were used to establish morphology, structure and composition, and the presence of Mo was confirmed.     

Above-ground morphological predictors of rooting success in rooted cuttings of Jatropha curcas L.

Cuttings of 1–3 cm diameter and 45 cm length were collected during the first week of February from branches of previous year’s growth in a mature plantation of Jatropha curcas. The cuttings, without application of any growth regulator, were planted in nursery beds having loam: gravel (1:1 v/v) mixture rooting media. The nursery beds existed inside a polyethylene tunnel where intermittent misting was done. When sprouting percentage had stabilised, sprouted cuttings were removed from the media, and root and shoot characteristics of the cuttings were recorded. The number of roots and root length were found to be significantly correlated (P < 0.01) with one another as well as with sprout length, number of sprouts and number of leaves. The following equations were fitted for prediction of root characteristics of a cutting from of its above-ground characteristics: (i) No. of roots = −0.409 + 0.452 (no. of leaves) + 0.395 (sprout length), and (ii) Root length = 2.656 + 0.206 (no. of leaves) + 0.270 (sprout length); the sprout length and root length are in centimetres in both equations. Thicker cuttings possessed better root and above-ground characteristics.     

Predicting the properties of needlepunched nonwovens using artificial neural network

Needlepunching is a well‐known nonwoven process of converting fibrous webs into self‐locking or coherent structures using barbed needles. In this study, Artificial Neural Network (ANN) modeling technique has been used to predict the bulk density and tensile properties of needlepunched nonwoven structures by relating them with the main process parameters, namely, web area density, punch density, and depth of needle penetration. The simultaneous effect of more than one parameter on bulk density and tensile properties of needlepunched nonwoven structures have been investigated based upon the results of trained ANN models. A comparison is also made between the experimental and predicted values of fabric bulk density and tensile strength in the machine and crossmachine directions in unseen or test data sets. It has been inferred that the ANN models have achieved good level of generalization that is further ascertained by the acceptable level of mean absolute error obtained between predicted and experimental results. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009