Vacancy mechanism of oxygen diffusivity in bcc Fe: A first-principles study

Diffusivity of interstitial oxygen (O) in bcc iron (Fe) with and without the effect of vacancy has been investigated in terms of first-principles calculations within the framework of transition state theory. Examination of migration pathway and phonon results indicates that O in octahedral interstice is always energetically favorable (minimum energy) with and without vacancy. It is found that vacancy possesses an extremely high affinity for O in bcc Fe, increasing dramatically the energy barrier (∼80%) for O migration, and in turn, making the predicted diffusion coefficient of O in bcc Fe in favorable accord with experiments.     

Between the Local and the Global: History of Science in the European Periphery Meets Post‐Colonial Studies

The aim of this paper is to discuss two historiographical issues pertaining to the history of science in the European periphery. The first issue concerns the wide use of the centre‐periphery dichotomy in historical accounts discussing the diffusion and institutionalization of science across the world. The second issue concerns the use of appropriation (instead of transfer, or adaptation) as a means to overcome the diffusionist model in history of science. Recent work at the intersection of history of science with post‐colonial studies will provide the framework for reassessing these matters. As it will be shown, theoretical discussions about the history of science in post‐colonial context can help historians overcome the centre‐periphery dichotomy and turn European periphery into a privileged standpoint for showing the actual diversity of ‘European science.’ At the same time, the experience of post‐colonial studies can also help sharpen the historiographical tool of appropriation. The assumption that will be made is that by focusing on appropriation rather than on discovery and innovation (the favourite categories of much of mainstream historiography), or on transfer and adaptation (the favourite categories of the diffusionist model), historians of science can not only set aside the artificial distinctions of the diffusionist model, but also bring forward the re‐inventions, the conceptual shifts and the cultural adjustments, which are responsible for the emergence of science as a global phenomenon in the periphery. Especially concerning European periphery, the use of appropriation may bring forward the particular historical circumstances under which certain knowledge patterns gained universal epistemic authority as constitutive elements of an imagined European intellectual identity.     

Development and assessment of healthy properties of meat and meat products designed as functional foods

This review deals with the two major aspects to be considered in the context of meat-based functional foods and human health. One involves the different strategies used to improve (increase or reduce) the presence of bioactive (healthy and unhealthy) compounds in meat and meat products in order to develop potential meat-based functional foods; these strategies are basically concerned with animal production practices, meat processing and storage, distribution and consumption conditions. Since the link between the consumption of those foods and their potentially beneficial effects (improving health and/or reducing the risk of several chronic diseases) needs to be demonstrated scientifically, the second aspect considered is related to intervention studies to examine the functional capacity of meat-based potentially functional foods in humans, discussing how the functionality of a food can be assessed in terms of its effects on health in relation to both target body functions and risk factors.     

Information technology, operational, and management competencies for supply chain agility: Findings from case studies

Given the growing emphasis on the need for supply chain agility to sustain competitive advantage, this study explores the impact of the relationship between supply chain competence and supply chain agility on firm performance. Although the influence of supply chain agility on firm performance has been acknowledged, this study further articulates the relationship from the perspective of inter-organizational collaboration. We develop a conceptual model based on the resource-based view and employ a multi-case study method in this exploratory research. Our findings highlight the importance of distinguishing the difference between supply chain agility and supply chain competence and their impact on firm performance. This study contributes to the growing body of conceptual and empirical literature on supply chain agility and adds to the understanding of the complexity of supply chain competence.     

Fluid catalytic cracking optimisation using factorial design and genetic algorithm techniques

Statistical techniques coupled with genetic algorithm (GA) were used to identify optimal values of key operational variables in fluid catalytic cracking (FCC) process. A Kellog Orthoflow F fluid catalytic cracking process model was considered. It is known as a highly nonlinear process with a large number of variables with strong interactions among them. A reduced process model was obtained through factorial design technique to be used as a process function in the optimisation work giving as result the operational conditions that maximise conversion without infringing operational restrictions with savings in computational burden and time. An increase of 8.71% in process conversion was achieved applying GA as optimisation technique. © 2012 Canadian Society for Chemical Engineering     

A model for atomic hydrogen–bimetal interactions

The adsorption of atomic H on the bimetallic FeNi(111) surface has been studied by ASED-MO tight binding calculations. The energy of the system was calculated by the atom superposition and electron delocalization molecular orbital (ASED-MO) method. Seven H locations on the alloy surface were selected and the hydrogen atom was positioned in their energy minima configurations.     

Synthesis of novel copper ion-selective material based on hierarchically imprinted cross-linked poly(acrylamide-co-ethylene glycol dimethacrylate)

A novel hierarchically imprinted cross-linked poly(acrylamide-co-ethylene glycol dimethacrylate) using a double-imprinting approach for the Cu²⁺ selective separation from aqueous medium was prepared. In the imprinting process, both Cu²⁺ ions and surfactant micelles (cetyltrimethylammonium bromide – CTAB) were employed as templates. The hierarchically imprinted organic polymer named (IIP-CTAB), single-imprinted (IIP-no CTAB) and non-imprinted (NIP-CTAB and NIP-no CTAB) polymers were characterized by SEM, FTIR, TG, elemental analysis and textural data from BET (Brunauer–Emmett–Teller) and BJH (Barrett–Joyner–Halenda). Compared to these materials, IIP-CTAB showed higher selectivity, specific surface area and adsorption capacity toward Cu²⁺ ions. Good selectivity for Cu²⁺ was obtained for the Cu²⁺/Cd²⁺, Cu²⁺/Zn²⁺ and Cu²⁺/Co²⁺ systems when IIP-CTAB was compared to the single-imprinted (IIP-no CTAB) and non double-imprinted polymer (NIP-CTAB), thereby confirming the improvement in the polymer selectivity due to double-imprinting effect. For adsorption kinetic data, the best fit was provided with the pseudo-second-order model for the four materials, thereby indicating the chemical nature of the Cu²⁺ adsorption process. Cu²⁺ adsorption under equilibrium was found to follow dual-site Langmuir–Freundlich model isotherm, thus suggesting the existence of adsorption sites with low and high binding energy on the adsorbent surface. From column experiments 600 adsorption–desorption cycles using 1.8 mol L⁻¹ HNO₃ as eluent confirmed the great recoverability of adsorbent. The synthesis approach here investigated has been found to be very attractive for the designing of organic ion imprinted polymer and can be expanded to the other polymers to improve performance of ion imprinted polymers in the field of solid phase extraction.     

Graft Copolymers of Acrylonitrile onto Dextrin for Use in Separation Technologies

The use of polymers in enrichment and separation technologies has attracted a lot of interest in recent times. To develop low-cost and environmentally friendly technologies for the removal of metal ions from water systems, graft copolymers based on dextrin were synthesized by grafting poly(acrylonitrile) onto it. The optimum grafting conditions were evaluated for grafting by varying the nature and amount of solvent, changes in concentration of monomer and initiator, reaction time and temperature. Graft copolymers were further functionalized by partial hydrolysis, and were characterized by water uptake, FTIR, SEM and elemental analysis. Sorption of Fe²⁺ and Cr⁶⁺ ions on graft copolymers were investigated as a function of percent grafting, change in metal ion concentration, temperature and pH, to define their end-uses in separation technologies.