Comparison of selected mathematical functions for the analysis of growth behavior of items and physical interpretation of AvramiWeibull function

Empirical data of sigmoidal-shaped y(t) growth behavior of different types of items, such as papers and citations earned by individual and all successively published papers of selected top-cited authors, germination of tomato seeds and three different bacteria, are analyzed and compared by Avrami-Weibull, Verhulst (logistic) and Gompertz functions. It was found that: (1) Avrami-Weibull function describes different types of the data better than Gompertz and Verhulst funtions, and (2), in comparison with Verhulst and Gompertz functions, Avrami-Weibull function, expressed in the form: y(t)/ymax = 1-exp[(t/Q)q] (where ymax is the maximum value of y(t) when t ® ¥, and Q and q are constants), is equally very versatile in explaining the generation rate dy(t)/dt of items in terms of its parameters Q and q. Using the basic concepts involved in the derivation of Avrami-Weibull function for overall crystallization from melt and supersaturated solution, the growth behavior of cumulative number y(t) of items produced at time t by individual (simple) sources and collectives or groups of simple sources (i.e. complex or composite sources) is presented. Comparison of the process of receiving of citations by papers with the processes of occurrence of chemical reactions and crystallization of solid phases from melts and supersaturated solutions shows that this process is similar to that of overall crystallization of solid phases from melts and solutions. Analysis of growth of citations using Avrami-Weibull function to individual papers published by different authors shows that 1 < q < 4 for most cases. This suggests that the process of citations to individual articles is mainly determined by progressive nucleation mode involving both diffusion and integration of published knowledge.

Effect of Electrosynthesis Potential on Nucleation, Growth, Adhesion, and Electronic Properties of Polypyrrole Thin Films on Fluorine-Doped Tin Oxide (FTO)

Polypyrrole (PPy) is one of the most attractive conducting polymers for thin film applications due to its good electrical conductivity, stability, optical properties, and biocompatibility. Among the technologies in which PPy has gained prominence are optoelectronics and solar energy conversion, where transparent electrodes such as fluorine-doped tin oxide (FTO) or indium tin oxide (ITO) are frequently used. However, FTO substrates have the notable advantage that their components are widely available in nature, unlike those of ITO. Recognizing the importance that the FTO/polypyrrole system has gained in various applications, here, we studied for the first time the nucleation and growth mechanism of electro-synthesized PPy on FTO. Additionally, the effect of the synthesis potential (0.9, 1.0, 1.1, and 1.2 V vs. Ag/AgCl) on the homogeneity, adhesion, conductivity, and HOMO energy levels of PPy films was determined. From current–time transients and scanning electron microscopy, it was found that films synthesized at 0.9 and 1.0 V exhibit 3D growth with progressive nucleation (as well as lower homogeneity and higher adhesion to FTO). In contrast, films synthesized at 1.1 and 1.2 V follow 2D growth with instantaneous nucleation. It was also evident that increasing the polymerization potential leads to polymers with lower conductivity and more negative HOMO levels (versus vacuum). These findings are relevant to encourage the use of electro-synthesized PPy in thin film applications that require a high control of material properties.

A progressive nucleation mechanism enables stable zinc stripping–plating behavior

The preferential adsorption of cation additives enables the transformation of a zinc nucleation mechanism from instantaneous nucleation to progressive nucleation, which ultimately realizes a stable zinc stripping/plating behavior.

Spatial Configurations of Power in Anglo-Saxon England: Sidelights on the Relationships between Boroughs, Royal Vills and Hundreds

The complex social and administrative fabric of Anglo-Saxon England existed largely without urban environments. Based upon patterns of naming, this chapter examines relationships between local administrative districts (hundreds) and central places, arguing for the long-term persistence of pre-urban modes of social organisation in Anglo-Saxon England. Following a review of urban development in Anglo-Saxon England, neglected material is brought to bear on long-standing notions of urbanism which emphasise the progressive nucleation of social and administrative functions as a linear measure of social complexity. A new perspective is offered here which emphasises the limited extent of urban development in England before the 12th century and the robust nature of non-urban social complexity as a social system. Overall, the applicability of measures of social and administrative complexity drawn from ‘primary’ complex societies is questioned and a plea is made for approaching European post-Roman societies on their own terms rather than by comparison with ancient and classical ones.

Local and Average Structure of Yb-Doped Ceria through Synchrotron and Neutron Pair Distribution Function

As transport properties of doped ceria electrolytes depend significantly on the nature of the dopant and the defectivity, the design of new materials and devices requires proper understanding of the defect structure. Among lanthanide dopants, Yb shows some peculiar characteristics that call for a possible different defect structure compared to Gd and Sm conventional dopants, which could be linked to its poorer performance. For this purpose, we combine synchrotron and neutron powder diffraction exploiting the Rietveld and Pair distribution Function. By increasing its concentration, Yb produces qualitatively the same structural distortions as other dopants, leading to a domain structure involving the progressive nucleation and growth of nanodomains with a Yb2O3-like (C-type) structure hosted in a fluorite CeO2 matrix. However, when it comes to growing the C-type nanodomains into a long-range phase, the transformation is less pronounced. At the same time, a stronger structural distortion occurs at the local scale, which is consistent with the segregation of a large amount of oxygen vacancies. The strong trapping of VOs by Yb3+ explains the poor performance of Yb-doped ceria with respect to conventional Sm-, Gd-, and Y-doped samples at equal temperature and dopant amount.

STUDY ON PROPERTIES OF CoNi FILMS WITH Mn DOPING PREPARED BY MAGNETIC FIELDS INDUCED CODEPOSITION TECHNOLOGY

Magnetic field parallel to electric field was induced during plating process to prepare CoNiMn alloy films on copper substrate. Electrochemistry mechanism and properties of CoNiMn alloy films were investigated in this paper. Micro magnetohydrodynamic convection phenomenon caused by vertical component of current density and parallel magnetic field due to deformation of current distribution contributed directly to the improvement of cathode current and deposition rate. Cathode current of the CoNiMn plating system increased about 30% with 1[Formula: see text]T magnetic field induced. It was found that CoNiMn films electrodeposited with magnetic fields basically belonged to a kind of progressive nucleation mode. Higher magnetic intensity intended to obtain CoNiMn films with good crystal structures and highly preferred orientations. With the increase of magnetic intensities, surface morphology of CoNiMn alloy films changed from typically nodular to needle-like structures. Compared with coatings electrodeposited without magnetic field, CoNiMn alloy films prepared with magnetic fields possessed better magnetic properties. Coercivity, remanence and saturation magnetization of samples increased sharply when 1[Formula: see text]T magnetic field was induced during plating process.

ELECTRODEPOSITION OF CuZn ALLOYS FROM THE NON-CYANIDE ALKALINE BATHS

Effect of copper sulfate on CuZn alloys electroplating from non-cyanide baths are investigated by different electrochemical methods. Cyclic voltammetry and current transient measurements are used to characterize the CuZn alloys electroplating system in order to analyze the nucleation and growth mechanism. The reduction of Cu and CuZn alloy on sheet iron substrates shows an instantaneous nucleation process. However, the reduction of Zn on sheet iron substrates shows a progressive nucleation process. The structure and surface morphology of CuZn alloys are analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The morphology of CuZn alloys obtained with 50 g L-1 copper sulfate presents a smooth and compact deposit and the size of crystal particle is uniform.

Study of Substrate for the Zinc Electrode in Acid Zn-PbO2 Flow Battery

An investigation into the suitability of carbon materials, metallic lead and its alloys as substrates for the zinc electrode in acid Zn-PbO2 flow batteries was performed. No maximum current appears on the potentiostatic current transients recorded for the zinc deposition on the lead and its alloys. With increasing the overpotential, the progressive nucleation turns to be the 3D-instantaneous nucleation process employed for the resin-graphite composite. Hydrogen evolution on the graphite composite is effectively suppressed due to the doping of polymer resins. The rate of hydrogen evolution reaction on the lead is relatively weak, but on the lead alloys, the hydrogen evolution conversely becomes serious to a certain degree. Though the exchange current density of the zinc deposition and dissolution process on the graphite composite is relatively low, the zinc corrosion is weakened to a great extent. With the increase of deposition time, the zinc deposits tend to be more compact. Zinc galvanostatic charge-discharge cycling on the graphite composite reveals that the coulombic of over 90% can be found, exhibiting an excellent cycling stability.