Hydrodynamics,mass transfer,and photocatalytic phenol selective oxidation reaction kinetics in a fixed TiO2 microreactor

Photocatalytic phenol dissociation was studied in a microreactor, with a TiO₂ layer immobilized on the reactor inner walls. Experiments were conducted for various residence times, initial concentrations, pH values, and UV light irradiation intensities. The intermediates and products (catechol, hydroquinone, and resorcinol) were quantitatively investigated to determine the predominant reaction pathways for the investigated anatase catalyst. A three‐dimensional mathematical model was used to simulate the heterogeneous photocatalysis reaction conditions with Langmuir–Hinshelwood mechanism, considering the adsorption/desorption thermodynamic equilibria, and for kinetic parameter estimation via regression analysis. The effectiveness factor, Thiele modulus, and the correction function were calculated to determine the pore diffusion effects. The value of pH had the dramatic effect of lowering the reaction rate due to the competitive adsorption of hydroxide ions and protons on the catalyst surface. A phenol conversion of 79.5% was achieved at the residence time of 7.22 min, but without total mineralization. © 2014 American Institute of Chemical Engineers AIChE J, 61: 572–581, 2015     

Online fuzzy identification for an intelligent controller based on a simple platform

The paper presents the identification issues of the self-tuning nonlinear controller ASPECT (Advanced control algorithmS for ProgrammablE logiC conTrollers). The controller is implemented on a simple PLC platform with an extra mathematical coprocessor, but is intended for the advanced control of complex processes. The model of the controlled plant is obtained by means of experimental modelling. A special batch-wise algorithm that is based on the Takagi–Sugeno model and uses “fuzzy instrumental variables” technique is described in the paper. Many robustness problems of the classical adaptive approaches can be circumvented to some extent by the proposed batch-wise approach combined with a supervisory mechanism. The paper also includes some experimental results on the hydraulic pilot plant and some simulation case studies.     

Identification of dynamical systems with a robust interval fuzzy model

In this paper we present a new method of interval fuzzy model identification. The method combines a fuzzy identification methodology with some ideas from linear programming theory. On a finite set of measured data, an optimality criterion that minimizes the maximal estimation error between the data and the proposed fuzzy model output is used. The idea is then extended to modelling the optimal lower and upper bound functions that define the band that contains all the measurement values. This results in a lower and an upper fuzzy model or a fuzzy model with a set of lower and upper parameters. The model is called the interval fuzzy model (INFUMO). The method can be used when describing a family of uncertain nonlinear functions or when the systems with uncertain physical parameters are observed. We believe that the fuzzy interval model can be very efficiently used, especially in fault detection and in robust control design.     

Effectiveness of fundamental resonant frequency for determining the elastic properties of Argentinean Eucalyptus grandis in structural sizes

The present paper reports the results of an investigation regarding the elastic properties of Argentinean Eucalyptus grandis by the dynamic method of measuring the fundamental frequencies of vibration. It aims at scrutinising how that method is suitable to this timber species. For this purpose an empirical research project with one sample of boards and four samples of beams in structural sizes exhibiting a wide range of variation in quality was carried out. The results give evidence of the effectiveness of this method for determining the elastic properties for Argentinean Eucalyptus grandis in different sizes, and that it is reliable for pieces of high quality as well as for those containing important strength and stiffness reducing factors, such as the presence of pith, among others.     

Untersuchungen zur Lastverteilung in Nagelverbindungen

An existing model has been extended to study the influence of plastic deformations on the load distribution in multiple-pin timber joints. The model was verified experimentally with tension tests on double shear specimens made from spruce and connected with nine nails aligned parallel to the direction of loading. The test results correspond well to the model results. There is no significant influence of number of nails on ultimate load.     

Strength and stiffness of ring and shear-plate connections

The development of Eurocode 5, the future European timber design code which is based on the partial safety coefficient method, means a change of timber design code formats in a number of European countries. Because of the change in the code format from allowable values towards partial safety coefficients, characteristic values of strength and stiffness of materials and connections are needed. In order to establish characteristic values of the strength and stiffness of ring and shear-plate connections, existing test data have been evaluated. The results of the evaluation correspond well to a mechanical model assuming a shear block failure of the wood as the governing failure mode.     

Imperfektionsannahmen für Holzdruckstäbe

Measurements of the imperfections of timber columns in 13 different buildings are presented. The values refer to the inclination as well as the initial curvature of the column axis, the dimensions of the cross-sections and the moisture content of the columns. The geometrical imperfections turned out to be on the safe side when compared with the assumed values presently used for design calculations. A method is proposed to develop more realistic assumptions for initial imperfections in design codes.     

Machine strength grading of Argentinean<Emphasis Type="Italic"> Eucalyptus grandis</Emphasis>

The present paper reports the results of an investigation regarding the possibility of machine strength grading sawn timber of Argentinean Eucalyptus grandis. In order to assess the usefulness of each parameter for predicting the mechanical properties of this timber species, and to propose strength, stiffness and density profiles, an empirical research project with four samples of beams and one sample of boards subjected to bending, and another sample of boards subjected to tension parallel to the grain, was carried out. The results obtained with specimens in structural sizes reveal the more important single and combined parameters for machine strength grading this timber species, and allow to analyse strength, stiffness and density profiles in comparison with the international strength class system established in the European standard EN 338.     

Development of colloidal carbon-based immunochromatographic strip for rapid detection of carbaryl in fruit juices

The differences in lipid content will lead to differences in protein structure and gel properties and it is a nice model system, so our study, based on the production process for Zhongxiang tofu, used soy protein isolate (SPI) as raw material and adopted circular dichroism and Raman spectrum to investigate the influence of different lipid content on protein secondary structure in tofu. Texture profile analysis and differential scanning calorimetry were used to analyze the influence of lipid on gel texture properties and state of water. The interactive mechanism at microscopic level was investigated by means of scanning electron microscopy. The results show that the additional lipid reacted with the soy protein and the lipid became a component of a newly formed molecular membrane. With an increase in added lipid, SPI gel hardness was reduced, while springiness increased. The proportion of α-helix and β-sheet in SPI gel at 16% (w/v) lipid are 4.0 and 26.0%, respectively. The equilibrium water content tended to decrease when lipid content was increased.