A stress analysis of a shaft with a press-fitted hub subjected to cyclic axial loading

This paper presents a calculation of the stress distribution in a shaft with a press-fitted hub subjected to axial fretting fatigue. Both normal contact stresses and frictional shear stresses at the shaft-hub interface are included in the model. The solution of Airy's function is obtained by means of Fourier integrals. The results are presented for different combinations of hub length, shaft radius and non-slip area and for various values of the coefficient of friction. Special consideration was given to the axial component of the stress, σ_z, as this is the most important stress component in the initiation and propagation of fatigue cracks. Finally, the paper deduces the implications arising from the stress analysis on the fretting fatigue of the junction studied.     

Logarithmic aggregation operators and distance measures

The Hamming distance is a well‐known measure that is designed to provide insights into the similarity between two strings of information. In this study, we use the Hamming distance, the optimal deviation model, and the generalized ordered weighted logarithmic averaging (GOWLA) operator to develop the ordered weighted logarithmic averaging distance (OWLAD) operator and the generalized ordered weighted logarithmic averaging distance (GOWLAD) operator. The main advantage of these operators is the possibility of modeling a wider range of complex representations of problems under the assumption of an ideal possibility. We study the main properties, alternative formulations, and families of the proposed operators. We analyze multiple classical measures to characterize the weighting vector and propose alternatives to deal with the logarithmic properties of the operators. Furthermore, we present generalizations of the operators, which are obtained by studying their weighting vectors and the lambda parameter. Finally, an illustrative example regarding innovation project management measurement is proposed, in which a multi‐expert analysis and several of the newly introduced operators are utilized.     

Analysis of Microencapsulation Ability of Essential Oils during Spray Drying

Results of preliminary investigations of the preservation of elemi (E) and peppermint (M) oils in a maltodextrin microcapsule during spray drying of emulsion in a laboratory dryer are discussed. The ratio of maltodextrin to water in the emulsion was 30:70, and the content of each oil 10, 20, and 30 wt·% in relation to maltodextrin. Product quality and results of the process were estimated on the basis of microscopic features of the powder (the shape and size of microparticles) and its density, moisture content and water vapor sorptivity. The efficiency of encapsulation was estimated by specifying the content of essential oil in the product. The compositions of initial oils and the oils contained in the emulsion, inside and on the capsule surface were compared. The positive results of this study justify the necessity of further research and provide a perspective for developing novel technologies.     

Analysis of Microencapsulation Ability of Essential Oils during Spray Drying

Results of preliminary investigations of the preservation of elemi (E) and peppermint (M) oils in a maltodextrin microcapsule during spray drying of emulsion in a laboratory dryer are discussed. The ratio of maltodextrin to water in the emulsion was 30:70, and the content of each oil 10, 20, and 30 wt·% in relation to maltodextrin. Product quality and results of the process were estimated on the basis of microscopic features of the powder (the shape and size of microparticles) and its density, moisture content and water vapor sorptivity. The efficiency of encapsulation was estimated by specifying the content of essential oil in the product. The compositions of initial oils and the oils contained in the emulsion, inside and on the capsule surface were compared. The positive results of this study justify the necessity of further research and provide a perspective for developing novel technologies.     

Automatic profiling of a steady state temperature field in thermochemical systems and devices

This article presents a method of the steady state temperature profiling in the case of industrial thermochemical systems. A problem of this type represents an important element of the production processes in different industrial area such as material engineering, manufacturing of semiconductor devices, very large scale integration (VLSI) systems, monocrystals growth, etc. The proposed method is oriented toward the automation of the profiling process, allowing to significantly reduce the duration of this operation. The paper covers the theoretical basis of the method as well as examples of industrial applications.     

Stabilization of Mineral Suspensions by Guar Gum in Potash Ore Flotation Systems

The adsorption of guar gum on illite and dolomite was studied as a function of polymer concentration and ionic strength. The adsorption results were correlated with colloid stability of aqueous suspensions of these two minerals. The adsorption density of guar gum on illite was not affected by the ionic strength of the system. Guar gum adsorption on dolomite was found to strongly decrease at higher electrolyte concentrations. Low concentrations of guar gum brought about flocculation of the minerals while higher dosages led to steric re‐dispersion. Results presented here are compared with previously published results for carboxymethyl cellulose (Pawlik et al., J. Colloid Interface Sci. 260 , 251‐258 (2003)).     

Thermodynamic and economic analysis of heat storage application in co‐generation systems

The possibility of improvement of the energy performance and economic feasibility of a CHP plant by the use of hot water storage tank is analysed in the paper. An energy balance of a system consisting of a CHP module, a peak boiler and a heat storage unit has been built and the storage efficiency has been defined. Heat transfer in storage tanks and its influence on the energy balance is discussed. A numerical model of heat transfer in the storage tank is presented. The thermodynamic and economic optimum of the tank volume for a sample co‐generation plant has been found. It has been eventually proved that the installation of a heat storage unit provides reduction of fuel consumption in the system. Copyright © 2004 John Wiley & Sons, Ltd.     

Characterization of the coal fly ash for the purpose of improvement of industrial on-line measurement of unburned carbon content

The influence of selected properties of fly ash on the measurements of an on-line analyser was described. Fly ash studied in the research originated from the pulverized coal fired boiler. The samples were taken using an inspection method within a period of 3 months. Systematic observation of the properties of the ash allowed monitoring of the work of the industrial analyzer during a relatively long period of the power plant work. Samples of coal fly ash were examined for their chemical and physical properties. Morphology was analysed by scanning electron microscopy. Unburned carbon content in fly ash was determined by using loss-on-ignition (LOI) and thermogravimetry analysis (TGA). The particle size distribution of fly ash was examined. Correlation between laboratory and on-line industrial measurements of the unburned carbon content of ash was discussed.     

Preface

Journal of Materials Synthesis and Processing -