An Invisible Logo Watermarking Using Arnold Transform

AbstractDigital watermarking is the process of hiding information into the digital content. The method of embedding a smaller logo image into the host image is called logo watermarking. The system proposes an invisible and secure watermarking. The key entered initially determine the location of embedding and thus classified the host image to white and black textured regions. The logo image is then transformed using Arnold transform. Discrete Wavelet Transform (DWT) technique is employed for embedding the transformed logo into the white textured regions. Watermark extraction is done by entering the same key which was already entered during embedding. The system is secure and the logo is imperceptible within the host image. Finally for analysis, PSNR value has been used as a metric for determining the quality of the recovered image

Ni 30 Ti 50 Pt 20 High Temperature Shape Memory Alloy (HTSMA) Wires: Processing Related Issues

Abstract There is a growing demand for high temperature shape memory alloys (HTSMAs) for applications in areas such as aeroengines, chemical industries, and nuclear power plants, where the ambient temperature is relatively high (150-350°C). Platinum addition to binary NiTi, with Pt substituting for Ni, has been found to raise the transformation temperatures of the alloy with the advantage of retaining the transformation hysteresis in the range 25-35°C. In the present study, a NiTiPt alloy was selected for processing into the wire form for applications in the range 200-250°C. Addition of Pt of about 20 at.% to binary NiTi was required to raise the transformation temperatures of the alloy above 200°C. It was found that Pt addition significantly changed the processing characteristics of the NiTiPt alloy from those of binary NiTi alloys. For successful processing of the NiTiPt wires, it was necessary to modify the process usually followed for binary NiTi alloys. Also, additional steps were incorporated to overcome the problems inherent to this alloy system. Some of these aspects related to processing of this alloy in wire form are discussed in this paper

Vacuum induction melting of NiTi shape memory alloys in graphite crucible

Vacuum induction melting (VIM) is the most widely used process for the commercial production of NiTi alloys. But, the major drawback in VIM is the carbon contamination of the ingot from the graphite crucible. During melting, carbon reacts with Ti and forms TiC. This alters the Ni/Ti ratio in the alloy and thereby changes the transformation temperatures drastically. Also, the TiC particles in the matrix hinder the workability of the alloy as well as the memory properties of the products. The present experimental study deals with the VIM of NiTi alloys melted in graphite crucible wherein it has been shown that the carbon pick up in the melt can be reduced significantly when Ni and Ti are placed in the graphite crucible by a novel method of charging. The cast ingots (weighing 7x2013;8 kg each) were subjected to various secondary metal processing operations viz., forging, rolling and wire drawing. The properties of the wire products were evaluated

Awareness about new guidelines of national tuberculosis elimination program among medical college faculty

Background: Physicians and faculty working in Medical Colleges play a major role in tuberculosis (TB) control. Their knowledge, attitude, and practices can affect the treatment and care of TB patients significantly. Objectives: The objectives were to assess the awareness about new guidelines of National TB Elimination Program (NTEP) among medical college faculty. Methods: A cross-sectional study was carried out among 95 faculties. They were given anonymous self-administered questionnaire with 23 questions. One mark was given for each correct answer. We classified correct knowledge as score >10 and poor knowledge as score <10. Yates-corrected Chi-square was used to study the association between variables and outcomes. P 0.05 was considered as statistically significant. Results: Questions about case detection rate, cure rate, incentives to private practitioner, bedaquiline, and follow-up of patients after completion of treatment were very poorly answered (<10 persons had correct knowledge). Only 17 could answer about the fixed-dose combinations, 10 about 99 Directly Observed Treatment Short-Course (DOTS) chemotherapy, and 13 about the choice of treatment in HIV-TB. Best answered questions were about the drugs used in each DOTS category, categories of DOTS, what are multidrug-resistant TB, extensive drug-resistant TB, and definition of presumptive case of TB. Overall, 58 faculties (61.1%) had poor knowledge with a score <11. The remaining 37 (38.9%) had correct knowledge with a score 11 or more. Correct knowledge was not found to be associated with age, sex, and designation but was associated with professional experience, with higher experience being associated with poor knowledge (P < 0.05). Conclusion: Majority of the faculty in the studied medical colleges had poor knowledge about new updates/guidelines in the NTEP. Professional experience was found to be significantly associated with the correct knowledge on recent updates in NTEP

Effect of intermittent overload cycles on thermomechanical fatigue life of NiTi shape memory alloy wire

Effect of intermittent overload cycles on fatigue behavior of NiTi shape memory alloy wire during thermomechanical cycling (TMC) has been evaluated. Results showed that fatigue life of NiTi is enhanced when the intermittent overload is above certain minimum level. An enhancement in fatigue life by ~50 pct is observed when the overload ratio is 2.0. Accumulation of plastic strain in the material under such TMC condition is found to be relatively high compared to that of TMC with no overload cycles

An investigation on the hardness and corrosion behavior of MWCNT/Mg composites and grain refined Mg

In the present work, multi walled carbon nanotubes (MWCNT) reinforced magnesium (Mg) matrix composite was fabricated by friction stir processing (FSP) with an aim to explore its mechanical and electrochemical behavior. Microstructural observations showed that the thickness of the produced composite layer was in the range of 2500 μm. FSP resulted uniform distribution of CNT near the surface while agglomerated layers in the subsurface. Grain refinement of Mg achieved by FSP improved the hardness but significant enhancement in the hardness value was observed for FSPed MWCNT/Mg composites. Potentiodynamic polarization studies revealed that the increase in corrosion current density was observed for MWCNT/Mg composite compared with grain refined Mg and pure Mg, implying the significance of secondary phase (MWCNT) in decreasing the corrosion resistance of the composite.(OLD) MSE-