Synthesis and characterization of polyaniline doped with organic acids

Spectroscopic [UV–visible and Fourier transform IR (FTIR)] and thermal properties of chemically synthesized polyanilines are found to be affected by varying the protonation media (acetic, citric, oxalic, and tartaric acid). The optical spectra show the presence of a greater fraction of fully oxidized insulating pernigraniline phase in polyaniline doped with acetic acid. In contrast, the selectivity in the formation of the conducting phase is higher in oxalic acid as a protonic acid media. The FTIR spectra of these polymers reveal a higher ratio of the relative intensities of the quinoid to benzenoid ring modes in acetic acid doped polyaniline. Scanning electron micrographs revealed a sponge‐like structure derived from the aggregation of the small granules in acetic acid and oxalic acid doped polyaniline. A three‐step decomposition pattern is observed in all the polymers, regardless of the protonic acid used for the doping. The second step loss related to the loss of dopant is found to be higher in the oxalic acid doped polymer. In accordance with these results the conductivity is also found to be higher in oxalic acid doped material. The temperature dependent conductivity measurements show the thermal activated behavior in all the polymers. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2043–2049, 2004     

Enzymes immobilized on montmorillonite: comparison of performance in batch and packed-bed reactors

Summary The enzymes a-amylase, invertase and glucoamylase were immobilized on acid activated montmorillonite using two techniques, viz. adsorption and covalent binding, and their activities were tested in a batch and packed-bed reactor and were compared. The packed-bed reactor showed an improved performance for all immobilized enzymes, which was attributed to lowering of diffusional restrictions to mass transfer. Lower activity in case of batch reactor for immobilized invertase was due to a combined effect of loss of native conformation of enzyme on account of immobilization and mass transfer resistances due to improper diffusion of substrate to the active site of enzyme. For immobilized glucoamylase, the packed-bed reactor demonstrated exceptionally high activity that was very close to the free enzyme. Covalently bound glucoamylase showed higher activity than the free enzyme.     

On finding the nucleolus of an n-person cooperative game

Kohlberg (1972) has shown how the nucleolus for ann-person game with side-payments may be found by solving a single minimization LP in case the imputation space is a polytope. However the coefficients in the LP have a very wide range even for problems with 3 or 4 players. Therefore the method is computationally viable only for small problems on machines with finite precision. Maschler et al. (1979) find the nucleolus by solving a sequence of minimization LPs with constraint coefficients of either –1, 0 or 1. However the number of LPs to be solved is o(4 ⁿ ). In this paper, we show how to find the nucleolus by solving a sequence of o(2 ⁿ ) LPs whose constraint coefficients are –1, 0 or 1.     

Strategic commitment to price to stimulate downstream innovation in a supply chain

It is generally in a firm’s interest for its supply chain partners to invest in innovations. To the extent that these innovations either reduce the partners’ variable costs or stimulate demand for the end product, they will tend to lead to higher levels of output for all of the firms in the chain. However, in response to the innovations of its partners, a firm may have an incentive to opportunistically increase its own prices. The possibility of such opportunistic behavior creates a hold-up problem that leads supply chain partners to underinvest in innovation. Clearly, this hold-up problem could be eliminated by a pre-commitment to price. However, by making an advance commitment to price, a firm sacrifices an important means of responding to demand uncertainty. In this paper we examine the trade-off that is faced when a firm’s channel partner has opportunities to invest in either cost reduction or quality improvement, i.e. demand enhancement. Should it commit to a price in order to encourage innovation, or should it remain flexible in order to respond to demand uncertainty. We discuss several simple wholesale pricing mechanisms with respect to this trade-off.     

Inequivalent quantizations for non-linear σ model

We compute the homotopy groups ₀ and ₁ of the classical configuration space of anO(3) invariant field theory on ×, where is a compact two dimensional manifold for arbitrary genusg and- denotes the time coordinate. We also present the finite dimensional, unitary, irreducible, inequivalent representations of the appropriate fundamental groups and comment on some of their implications.     

EPR studies of a molybdenyl complex in single crystals of NH4Cl

Electron paramagnetic resonance of [MoOCl₅]^2? has been studied in single crystals of NH₄Cl. At room temperature the interaction of the unpaired electron with both the even and odd isotopes of molybdenum has been observed. The existence of metal-halogen π bonding is established by the observation of the ligand superhyperfine interaction at liquid nitrogen temperatures. Various possible models corresponding to the different spatial configurations of the molybdenyl complex in the lattice are considered to explain the experimentally observed features. The spectra are analysed using the usual spin-hamiltonian corresponding to tetragonal symmetry. The spin-hamiltonian parameters obtained are: g_∥ = 1.964, g_? = 1.945, A_∥ = 75.53 × 10^?4 cm^?1, A_⊥ = 38.42 × 10^?4 cm^?1.     

Adoption and use of AI tools: a research agenda grounded in UTAUT

This paper is motivated by the widespread availability of AI tools, whose adoption and consequent benefits are still not well understood. As a first step, some critical issues that relate to AI tools in general, humans in the context of AI tools, and AI tools in the context of operations management are identified. A discussion of how these issues could hinder employee adoption and use of AI tools is presented. Building on this discussion, the unified theory of acceptance and use of technology is used as a theoretical basis to propose individual characteristics, technology characteristics, environmental characteristics and interventions as viable research directions that could not only contribute to the adoption literature, particularly as it relates to AI tools, but also, if pursued, such research could help organizations positively influence the adoption of AI tools.