Particle nucleation in a forested environment

Peer reviewe

Microstructural homogenization and substantial improvement in corrosion resistance of mechanically alloyed FeCoCrNiCu high entropy alloys by incorporation of carbon nanotubes

FeCoCrNiCu high entropy alloy (HEA) powder was produced by mechanical alloying. Carbon Nanotubes (CNTs) were mixed in the HEA powder (0.1, 0.2, 0.5, 1.0, 1.5, 2.0, 3.0, 5.0, 7.0 wt.% of CNT) and then the mixture was consolidated by spark plasma sintering at 800°C. Phase constitution of the pellets was sensitive to the CNT amount. With smaller quantities of CNTs (upto 2 wt.%), the pellets contained a mixture of two different face centred cubic (fcc) phases along with σ phase. With increase in the CNT amount (till 2 wt.%), a gradual decrease in the volume fraction of one of the fcc phase occurred leading to microstructural homogenization. Higher CNT additions (3, 5 and 7 wt.%) led to re-evolution of inhomogeneous microstructure containing chromium carbide phase and the two different fcc phases. Corrosion behaviour measurements showed that with continued addition of CNTs, reduction in the corrosion rate happened till 2wt.% CNT. Beyond this, a significant enhancement in the corrosion rate was noticed for pellets with 3, 5 and 7 wt.% CNT additions. Between the pristine HEA pellet and the pellet with optimum CNT amount (2 wt.%), 88.6 % reduction in the corrosion rate was measured. The enhancement in the corrosion resistance was attributed to an increase in the chemical homogeneity, which reduced the possibility of galvanic coupling. The decrease in the corrosion resistance beyond the optimum CNT (2 wt.%) was attributed to the re-appearance of chemical heterogeneity and evolution of chromium carbide (Cr23C6) phase, which causes intergranular corrosion in these systems. © 202

Controlled adsorption of titanium(IV) oxide particles on electroplated zinc coatings to improve the corrosion resistance of chromium(VI)‐free conversion layers

Adsorption of nano-scaled titanium(IV) oxide particles on electroplated zinc is per-formed by a simple dip-coating technique in an aqueous titanium(IV) oxide suspen-sion prepared with a stirred media mill. X-ray photoelectron spectroscopy, scanningelectron microscopy and X-ray fluorescence spectroscopy are carried out to inves-tigate the composition of the zinc surface and the thickness and porosity of the ad-sorbed titania films. The zinc surface formed during the electrodeposition processis of oxyhydroxide nature and the thickness of the adsorbed titania particle layer iscontrolled by the pH value and the solid concentration of the suspension. In therange of 10 wt.%–30 wt.% titanium(IV) oxide, a linear dependence between the tita-nia film thickness and the solid content of titania particles in the suspension isfound. Highest film thicknesses are obtained in alkaline media (pH9). At13.5 wt.% titania particles and pH values below pH=2.4, the titania particle film isnot closely packed and the zinc layer underneath is still visible in electron micro-scopy, which is a prerequisite for imbedding these particles by a thin second zinclayer for formation of a robust chromium(VI)-free passivation layer containing thetitania particles

Evaluation of Primary Immunization Coverage of Infants Under Universal Immunization Programme in an Urban Area of Bangalore City Using Cluster Sampling and Lot Quality Assurance Sampling Techniques

<b>Research Question:</b> Is LQAS technique better than cluster sampling technique in terms of resources to evaluate the immunization coverage in an urban area? <b> Objective:</b> To assess and compare the lot quality assurance sampling against cluster sampling in the evaluation of primary immunization coverage. <b> Study Design:</b> Population-based cross-sectional study. <b> Study Setting:</b> Areas under Mathikere Urban Health Center. <b> Study Subjects:</b> Children aged 12 months to 23 months. <b> Sample Size:</b> 220 in cluster sampling, 76 in lot quality assurance sampling. <b> Statistical Analysis:</b> Percentages and Proportions, Chi square Test. <b> Results:</b> (1) Using cluster sampling, the percentage of completely immunized, partially immunized and unimmunized children were 84.09&#x0025;, 14.09&#x0025; and 1.82&#x0025;, respectively. With lot quality assurance sampling, it was 92.11&#x0025;, 6.58&#x0025; and 1.31&#x0025;, respectively. (2) Immunization coverage levels as evaluated by cluster sampling technique were not statistically different from the coverage value as obtained by lot quality assurance sampling techniques. Considering the time and resources required, it was found that lot quality assurance sampling is a better technique in evaluating the primary immunization coverage in urban area