Impedance and AC Conductivity of GdCr1−xCoxO3 (x = 0, 0.33, 0.5, 0.67 and 1) Perovskites

Perovskite series GdCr_1?xCo_xO₃ (x = 0, 0.33, 0.5, 0.67 and 1) was obtained using a solution combustion method. The powder XRD was used for identification and structural characterization of the obtained perovskites. All compounds crystallize within the space group Pnma. The morphology of samples was studied using SEM. The impedance and AC conductivity of GdCr_1?xCo_xO₃ were studied using impedance spectroscopy in a frequency range from 10 Hz to 10 MHz and in temperature interval 297–337 K. Changes in electric modulus and DC conductivity, with increasing of the value of x in the structures, were observed. The AC conductivity obeyed the universal power law, σ(ω) = σ(0) + Aωⁿ and revealed semiconductor behavior. The calculated activation energies of existing processes varied with the cobalt content and applied frequency. The impedance spectra showed non‐Debye behavior with a distribution of relaxation times for relaxation and conductive processes. The conduction mechanism for pure orthochromite and orthocobaltite was defined and two types of conduction were observed in the investigated temperature range for the complex perovskites. In order to explain the results, an equivalent circuit with fitted values of circuit components was proposed.     

The size and effort estimates in iterative development

The quick delivery of a functionally truncated product is one of the most common results in iterative development, and has become the predominant development approach. One of its drawbacks is the appearance of incomplete artifacts between iterations. Consequently, well-known size-estimation methods can not be used in iterative development. This paper addresses the problem of size estimation in iterative development. We present a novel approach that enables early size estimation using Unified Modeling Language (UML) artifacts. The approach incorporates self-improvement steps that increase the estimation accuracy in subsequent iterations. The demonstration of its applicability and research results are also presented. The results anticipate the possibility of a significant improvement in size and effort estimates by applying the approach presented here.     

Influence of main emulsion components on the physical properties of corn oil in water emulsion: Effect of oil volume fraction,whey protein concentrate and Lepidium perfoliatum seed gum

The effect of composition (whey protein concentrate, Lepidium perfoliatum seed gum, and oil content) of corn oil-in-water emulsions on their physical properties, droplet size and viscosity was studied using response surface methodology (RSM). For each response, a second-order polynomial model was developed using multiple linear regression analysis. The results indicated that the response surface models were significantly fitted for all response variables studied. It was shown that all emulsion components greatly influenced the physical properties of emulsion and its overall stability during storage. The main effect of L. perfoliatum seed gum was observed to be significant in most of response surface models. Therefore, the concentration of this gum should be considered as a critical variable for the formulation of emulsions. The overall optimum region resulted in a desirable emulsion was predicted to be obtained by combined level of 0.59% L. perfoliatum seed gum, 6% WPC and 21.95% oil volume fraction.     

Verification of the geological origin of bottled mineral water using artificial neural networks

As a first step towards objective and cost-efficient verification of the geographical origin of commercially sold mineral water, we determined up to what extent the chemical composition of mineral water can be linked to the geology of the local water source. For this purpose, a dataset consisting of 145 European mineral water samples from a known geology was analysed using counter-propagation artificial neural networks (CP-ANNs) with supervised learning algorithm. The models were tested for recall ability (RA) and validated with a leave-one-out cross validation (LOO-CV).     

Visualization and quantification of liquid water transport in softwood by means of neutron radiography

Liquid water uptake in an orthotropic, cellular, hierarchical and natural material namely wood is investigated using neutron radiography. During water uptake in wood, liquid does not move up as a regular front as uptake rates differ in latewood and earlywood. In addition, moisture is adsorbed by the cell wall, resulting in a swelling that influences the process of moisture transport in wood. The high sensitivity of neutron to hydrogen atoms enables an accurate determination of the change in moisture content in the wood at the growth ring scale. The analysis of the spatial and temporal change of water content distribution shows that liquid water transport has different characteristics, depending on the direction of uptake and initial moisture content state.Our results show that latewood cells play a more significant role in water uptake than earlywood cells and that ray tracheids also contribute to liquid transport. Latewood tracheids possess smaller cell lumens than earlywood cells that make them the preferential pathways for transport along the longitudinal direction. The process of liquid uptake is different in the radial and tangential directions as the path of the liquid is more intricate, involving also the rays and requiring more often traversing pits. In tangential direction, water uptake is occurring first in the latewood with a subsequent radial redistribution towards the earlywood. In radial direction, the growth ring boundary decreases the liquid transport rate, an indication that a significant portion of the rays are interrupted at that location. The moisture uptake rate in initially moist specimens is seen to be higher. Liquid transport leads to sorption and thus swelling of the specimens, which was dealt with by affine registration. Water uptake in wood cellular structure is a three-dimensional process that is controlled by the morphologic and sorption properties of the material at its different scales.     

The Awesome and Capricious Language of Past,Present and Future Digital Moods

Can cultural progress be held back by linguistic limitations? Architect and educator Marjan Colletti , cofounder of London practice MAM-arch, examines the nouns, adjectives and adjectival compounds used by the architectural profession during the first and second digital turns. He reflects on how restricted vocabularies can cause initially forward-looking concepts to descend into the realm of doctrine and ‘-isms’, and argues that true advancement requires constant evolution of the language employed to describe it.     

Post-Digital Transdisciplinarity

Why are buildings generally credited to a single individual or firm, without acknowledging the numerous other participants in their creation? Marjan Colletti , founder and director of the REX|LAB robotic experimentation laboratory at the University of Innsbruck, reflects on the nature and implications of transdisciplinarity. With reference to REX|LAB's contribution to the highly collaborative 2015 show of Iris van Herpen's Quaquaversal ready-to-wear collection, he further considers the increasingly understated approach to technological presence in the post-digital age.     

The formation of hydrophobic and corrosion resistant surfaces on copper and bronze by treatment in myristic acid

The surface of freshly etched copper and bronze samples was modified by immersion in ethanol solutions of myristic (tetradecanoic) acid. Modification resulted in the formation of hydrophobic layers with contact angles up to 141°. Two kinds of surface structure were observed. The modified surface of copper was covered by a uniform layer containing nano-grains or knitted-like structure, whereas the modified surface of bronze was covered by a layer with lamellate patterns and nano-grains. The corrosion properties of bare and modified copper and bronze surfaces were tested by potentiodynamic polarization experiments in 0.014 M Na₂SO₄ + 0.024 M NaHCO₃ solution. The deduced effectiveness of corrosion inhibition by the modified layers on copper and bronze was up to 97 and 68%, respectively. Modification of the surface by immersion in an ethanol solution of myristic acid appears to be a promising treatment for improving the corrosion resistance of copper. The same treatment was not very effective when used on bronze.