Papers by Author: Jainagesh A. Sekhar

Abstract: The principle of maximum entropy generation rate principle is reviewed for its applicability in Materials Science. The principle of MEPR states that, if there are sufficient degrees of freedom within a system, it will adopt a stable state at which the entropy generation (production) rate is maximized. Where feasible, the system will also try and adopt a steady state. MEPR determines the most probable state. MEPR thus allows for pathway selections that can occur in an open thermodynamic system. Recent work also shows that isolated systems and closed thermodynamic systems also display this principle. The Belousov-Zhabitonsky reaction is also described in the Sgen context. Both solidification morphologies and micropyretic process generated morphologies are studied as examples of the Sgen and MEPR.

Abstract: Provided in this article are the quantitative and qualitative morphological results describing the action of several nanostructured surfaces for bactericidal and bacteriostatic action. Results are also provided to illustrate microbial corrosion and its impact. Biofilm formation is correlated to colony formation. Nanostructured surfaces, i.e. surfaces with welded nanoparticles are noted to display biocidal activity with varying efficacies. Porous nanostructures, on stainless steel and copper substrates, made of high purity Ag, Ti, Al, Cu, MoSi2, and carbon nanotubes, are tested for their efficacy against bacterial colony formation for both gram-negative, and gram-positive bacteria. Silver and Molybdenum disilicide (MoSi₂) nanostructures are found to be the most effective bactericidal agents with MoSi2 being particularly effective in both low and high humidity conditions. Bacteriostatic activity is also noted. The nanostructured surfaces are tested by controlled exposures to several microbial species including (Gram+ve) bacteria such as Bacillus Cereus and (Gram-ve) bacteria such as Enterobacter Aerogenes. The resistance to simultaneous exposure from diverse bacterial species including Arthrobacter Globiformis, Bacillus Megaterium, and Cupriavidus Necator is also studied. The nanostructured surfaces were found to eliminates or delay bacterial colony formation, even with short exposure times, and even after simulated surface abrasion. The virgin 316 stainless steel and copper substrates, i.e. without the nanostructure, always displayed rapid bacterial colony evolution indicating the lack of antimicrobial action. The efficacy of the nanostructured surface against colony formation (bacterial recovery) for E-Coli (two strains) and virus Phi 6 Bacteriophage with a host Pseudomonas Syringae was also studied. Preliminary results are presented that also show possible anti-fungal properties by the nanostructured MoSi₂. When comparing antimicrobial efficacy of flat polished surfaces (no curvature or nanostructure) with nanostructure containing surfaces (high curvature) of the same chemistry, shows that bacterial action results from both the nanostructure size and chemistry.

Abstract: About 32 million tons of aluminum is melted every year. A significant amount is lost to dross during primary and secondary melting operations. Typically, to overcome the dross loss, either a nitrogen cover or a chemical cover is used over the molten metal. A new method, that uses a cover of low-ionization air, has proven to be effective in significantly reducing the dross. The method, low-ionization plasma melting, and its impact on the environment and on melting energy efficiency are discussed in relation to some of the other historical innovations for aluminum processing.

Abstract: We explore an improved method for the measurement of innovation and innovative activity across long life-cycles especially where patentable technology plays a part in the innovation. In a previous publication we were able to distinguish four stages of a long life cycle. In this article we examine whether the patent life cycle and the production activity life cycle are related. Two conventional schools of thought commonly exist in reference to measurement of technical innovation, one suggesting the use of patents as the best indicator of innovative activity, and the other recommending alternative means, not using patent data. This article proposes a novel method of measurement utilizing yearly patent counts. A model was developed using nine metals whose yearly production activity was correlated with patent counts associated with the same materials. This correlated data was then entered into best-fit equations to obtain fitted patent and activity life cycle curves. Differences in the origins of these fitted curves were interpreted as lags of time in the life cycle of the patent or activity thus allowing for comparisons between patents and innovation activity. The behavior of the number of patents with time was found to be similar to production growth, making patents a measure and representation of technical innovation. In conclusion we were able to categorize the metals into three groups. Group 1, containing nickel and chromium, are metals whose patent activity is driving their production. Group 2, containing aluminum, zinc and copper, are metals in which production is driving the patenting. Group 3, which is composed of the Stage IV metals iron, manganese, molybdenum and tungsten, represents materials that have no current innovative activity that can be measured or correlated to the patent activity. The results suggest a fertile field of future research extending the initial pattern equation model to include R&D, Patents, and Performance, as well as Sales, as innovation activity. Further, the model shows promise for the analysis and assessment of existing and future industrial technology life cycles involving materials, processes, products, software and service innovations.