Surface engineering of titanium for biomedical applications by anodizing

Abstract: Competitive manufacturing implies fit for purpose and efficient manufacturing practices. Dental implants are biomedical parts that are manufactured from either Grade 4 or 5 Titanium alloy. In certain situations it may be beneficial for patient satisfaction purposes and for product identification marking to change the appearance (colour and reflectance) of the implant. In the present study, a TiO2 based coating is applied on commercially pure titanium (Grade 4) alloy substrates by the anodizing process. The objective of this study was to engineer the aesthetic appearance of the dental implants while monitoring its effect on aspects as regards to biocompatibility and function. Chromaticity (colour and hue) and reflectance are investigated as a function of the anodizing process parameters (electrolyte voltage, current and electrolyte). Grade 4 titanium was anodized in diluted sulphuric acid electrolyte at various voltages. The reflectance of the anodized specimens was measured with a spectrophotometer. Surface roughness, oxide film thickness and chemical composition of the oxide phase were measured. By varying the electrolyte voltage between 5 V to 40 V different colour ranges were produced. It can be concluded that the surface colour of anodized titanium is dependent on the oxide layer thickness and therefore the applied voltage. Conventional surface roughness did not change and was similar to the virgin material. Elevated voltages resulted in a more crystalline oxide layer. The aesthetic appearance of titanium implants may be improved

Stability Performance of Inductively Coupled Plasma Mass Spectrometry-Phenotyped Kernel Minerals Concentration and Grain Yield in Maize in Different Agro-Climatic Zones

Deficiency of iron and zinc causes micronutrient malnutrition or hidden hunger, which severely affects ~25% of global population. Genetic biofortification of maize has emerged as cost effective and sustainable approach in addressing malnourishment of iron and zinc deficiency. Therefore, understanding the genetic variation and stability of kernel micronutrients and grain yield of the maize inbreds is a prerequisite in breeding micronutrient-rich high yielding hybrids to alleviate micronutrient malnutrition. We report here, the genetic variability and stability of the kernel micronutrients concentration and grain yield in a set of 50 maize inbred panel selected from the national and the international centres that were raised at six different maize growing regions of India. Phenotyping of kernels using inductively coupled plasma mass spectrometry (ICP-MS) revealed considerable variability for kernel minerals concentration (iron: 18.88 to 47.65 mg kg–1; zinc: 5.41 to 30.85 mg kg–1; manganese: 3.30 to17.73 mg kg–1; copper: 0.53 to 5.48 mg kg–1) and grain yield (826.6 to 5413 kg ha–1). Significant positive correlation was observed between kernel iron and zinc within (r = 0.37 to r = 0.52, p < 0.05) and across locations (r = 0.44, p < 0.01). Variance components of the additive main effects and multiplicative interactions (AMMI) model showed significant genotype and genotype × environment interaction for kernel minerals concentration and grain yield. Most of the variation was contributed by genotype main effect for kernel iron (39.6%), manganese (41.34%) and copper (41.12%), and environment main effects for both kernel zinc (40.5%) and grain yield (37.0%). Genotype main effect plus genotype-by-environment interaction (GGE) biplot identified several mega environments for kernel minerals and grain yield. Comparison of stability parameters revealed AMMI stability value (ASV) as the better representative of the AMMI stability parameters. Dynamic stability parameter GGE distance (GGED) showed strong and positive correlation with both mean kernel concentrations and grain yield. Inbreds (CM-501, SKV-775, HUZM-185) identified from the present investigation will be useful in developing micronutrient-rich as well as stable maize hybrids without compromising grain yield

DRY SLIDING WEAR BEHAVIOUR OF PLASMA SPRAYED Al2O3-30%Mo, Mo & WC-12%Co COATINGS

The use of hard coatings to improve wear resistance of mechanical components is now well established. Of the advanced deposition techniques, plasma spraying is one of the most efficacious and adaptable process. Over the years, a variety of plasma sprayed ceramics, carbides and cermets have been tried as a replacement for the conventional coatings. The Molybdenum(Mo)is now being considered to be a future coating material for automotive engines. The WC–12%Co is well known for its high strength, hardness, toughness and wear resistance up to 5000C. The WC–Co coatings are widely used for tools, dies and wear resistant parts in variety of applications including machining, mining,metal cutting/forming, construction and other applications in the form of bulk parts or coatings. The fracture toughness of ceramics like Al2O3 can be enhanced by the addition Mo as a second phase. Due to its hardness and improved toughness Al2O3-Mo generally used in wear resistant components, such as water pump seals

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Analysis of Factors Influencing Dry Sliding Wear Behaviour of Laser Remelted Plasma Sprayed Mo Coating Using Response Surface Methodology

Plasma spraying is a process widely used to fabricate wear resistant coatings. However, various problems are associated with plasma spraying out of which poor bonding strength between the coating and the substrate and the high porosity in the as sprayed coatings are of major concern. In order to eliminate these problems and enhance wear performance, the laser remelting process has been used. The laser remelting of plasma sprayed Mo coatings alters the wear mechanism and improves the wear resistance. The wear mechanism and wear volume loss depend on the applied load, sliding speed and sliding distance. Hence, an effort has been made to investigate the effect of process parameters on volume loss using Response Surface Methodology (RSM) based mathematical models. The experiments were planned as per Central Composite Design (CCD). The investigations revealed that the applied load was the most dominant factor affecting the volume loss of the coating. The sliding speed, sliding distance and interaction effects were considered as the next important parameters influencing the volume loss. The investigation also reveals that, the wear volume loss depends on two wear mechanisms, one being the formations of grooves along surface tribo films and other being fracture of splats with delamination of the coating

Effect of waste mica on transfer factors of

A greenhouse pot culture experiment was conducted to study the effect of graded levels of waste mica (0, 10, 20 and 40 g kg-1) on reducing the radiocesium uptake by spinach (Spinacia olerecea L) and lettuce (Lactuca sativa L.) grown in 134Cs-contaminated (at 37 k Bq kg-1 soil) Inceptisols, Vertisols and Ultisols. The biomass yield, and potassium content and its uptake by crops have been significantly improved by waste mica application. The crops grown in Vertisols recorded higher biomass yield, and K content and its uptake as compared with Inceptisols and Ultisols. The average 134Cs transfer factor values recorded were : 0.21, 0.17 and 0.26 at the first cutting, 0.15, 0.12 and 0.28 at the second cutting and 0.07, 0.05 and 0.23 at the third cutting from Inceptisols, Vertisols and Ultisols, respectively. Waste mica significantly suppressed radiocesium uptake, the effect being more pronounced at 40 g mica kg-1soil. There exists an inverse relationship between the 134Cs transfer factors with plant potassium content and also the K uptake by the crop

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Not AvailableAn incubation experiment was conducted to determine the nitrification inhibition potential of Brachiaria humidicola (B. humidicola) and their effect on nitrification process. The pots soil was mixed 2 mg of nitrogen through ammonium sulphate. Seven treatments were evaluated viz. control, four root extracts of B. humidicola called as biological nitrification inhibitors (BNIs) (i.e., 70 % ethyl alcohol, 40 % ethyl alcohol, phosphate buffer solution and 2 M KCl salt solution extracts) and two standard chemical inhibitors i.e. dicyandiamide and neem oil coating. The amount of NH4?-N was reduced 20.66–11.91 lg g-1 soil and NO3--N increased 28.89–31.18 lg g-1 soil from 14th to 22nd day time interval. Percent nitrification inhibition was more in BNIs (70 and 40 % alcohol extract) treated soils compared to plant based and synthetic nitrification inhibitors. The nitrification inhibition by B. humidicola also varied it was maximum (64.71 %) observed at 14th day over 22nd day (49.63 %).Not Availabl