Numerical modeling of nonisothermal moisture transfer in biological colloidal porous materials

The authors derive and substantiate a system of equations of heat and moisture transfer in colloidal capillary-porous undersaturated media with account for the mutual effect of the vapor and liquid pressure, determined by the contribution of surface forces, and the temperature on the rate of interphase mass transfer and the thermocapillary flows. Examples are given of the numerical calculation of evolution of the moisture content and temperature fields and the kinetic dependences in a wide moisture content range for materials of biological origin, namely, yeast, soil. A comparison is made with experimental data.The work was carried out in 1992/93 on the basis of grant No. 1392/3-91, sponsored by the Science Committee of Poland.Academic Scientific Complex A. V. Luikov Heat and Mass Transfer Institute, Academy of Sciences of Belarus, Minsk, Belarus. Technical University of Lodz', Poland. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 66, No. 2, pp. 202–212, February, 1994.     

Kernel orthonormalization in radial basis function neural networks

This paper deals with optimization of the computations involved in training radial basis function (RBF) neural networks. The main contribution of the reported work is the method for network weights calculation, in which the key idea is to transform the RBF kernels into an orthonormal set of functions (using the standard Gram-Schmidt orthogonalization). This significantly reduces the computing time if the RBF training scheme, which relies on adding one kernel hidden node at a time to improve network performance, is adopted. Another property of the method is that, after the RBF network weights are computed, the original network structure can be restored back. An additional strength of the method is the possibility to decompose the proposed computing task into a number of parallel subtasks so gaining further savings on computing time. Also, the proposed weight calculation technique has low storage requirements. These features make the method very attractive for hardware implementation. The paper presents a detailed derivation of the proposed network weights calculation procedure and demonstrates its validity for RBF network training on a number of data classification and function approximation problems.     

Characteristics of the Thrust Bearing with Accelerating Slider

Thrust bearing characteristics are examined in the motion generated by the accelerating slider. The selected case is the situation where the fluid within the lubricating film initially is at rest and at time zero the infinitely long slider assumes a velocity which is a function of time. Numerical solutions to the governing differential equations are obtained for the case of constant but arbitrary acceleration and for the case of acceleration proportional to time. The corresponding previously published analytical solutions are compared with those numerical results.     

Generalized singular value decomposition in multidimensional condition monitoring of machines—A proposal of comparative diagnostics

With the modern metrology, we can measure almost all variables in the phenomenon field of working machine, and many of measuring quantities can be symptoms of machine condition. On this basis, we can form the symptom observation matrix (SOM) for condition monitoring. From the other side we know that contemporary complex machines may have many modes of failure, so-called faults, which form the fault space. Even if we apply some modern tool like singular value decomposition (SVD) for the fault extraction purpose, this multidimensional problem is not a simple one. Therefore, the question remains if one can learn considering similar problem when having SOM of similar machine observed just before. In this way, we can consider the application of generalized singular value decomposition (GSVD) to the machine condition monitoring problems, and uncover some new possibilities.     

Refinement of depth from stereo camera ego-motion parameters

An algorithm for refinement of depth (disparity) map from stereoscopic sequences is proposed. the method is based on estimation of ego-motion parameters of the camera system and frame-by-frame prediction of 3d scene feature point co-ordinates. disparity maps with sub-pixel accuracy were obtained without the need for disparity computations in each single frame.     

Nested median filtering for detecting T-wave offset in ECGs

The capabilities of a nonlinear signal decomposition method based on nested median filters for electrocardiogram (ECG) analysis are demonstrated. This method is comparable to linear scale-space filtering in terms of computation cost but outperforms it with regard to detection accuracy of characteristic points of ECGs (e.g. the T-wave offset). Obtained results are validated on the CSE database of ECGs     

Evaluation of various integration algorithms for transient inelastic response of shear walls

Inelastic dynamic response of building walls made of reinforced concrete is considered by using various explicit and implicit algorithms. The numerical examples show the computational efficiency of algorithms for different low and high walls.     

Importance of the triboemission process for tribochemical reaction

Chemical reactions under boundary lubrication conditions are distinct from those of thermochemical ones. Flash temperature is very short and holding in esteem the mechanically triggered chemistry and thermally triggered chemistry at the contact of asperities caused by the flash temperature effect, the following question arises. ‘Can this reaction initiation process be considered in terms of overcoming the activation energy by heat or by another form of energy’? The purpose of this paper is to discuss that question in terms of the hypothesis: The common denominator of tribochemical reactions is that they might be initiated by low-energy electrons. This is consistent with the negative-ion-radical action mechanism (NIRAM) approach assuming that tribochemical reactions are initiated by electrons in the energy-range of 1–4 eV. The hypothesis is also relevant to the next author's hypothesis saying that the intermediate reactive species of both tribochemical reactions and some heterogeneous catalytic reactions are produced by the same mechanism, governed by the NIRAM approach. The catalyst effect on a chemical reaction is to increase its rate. The reaction rate is further increased when the catalyst is under friction (tribocatysis). The primary objective of this work is to better understand mechanisms of tribochemical reactions and catalytic processes. To initiate thermochemical reactions, heat should be supplied. The same is due to heterogeneous catalytic reactions, however, the catalyst lowers the reaction activation energy. Even a very high calculated flash temperature is short lived, thus, it rather cannot initiate tribochemical reactions by heat. The present author assumes that flash temperature can be expressed in the form of the thermionic emission. Bearing this in mind, it is possible to hypothesize that heterogeneous catalytic reactions are also initiated by thermal electrons. Accordingly, the tribocatalytic process might be initiated and/or enhanced by triboelectrons. Important objective of this work is to better understand both tribochemical reactions and catalytic/tribocatalytic processes. Tribochemistry of simple environment friendly lubricant compounds and examples of water synthesis catalytic and tribocatalytic processes are presented and discussed.     

Effect of Particle Structure on Quality Retention of Bio-Products During Thermal Drying

To study the influence of particle structure on quality retention of hioproducts during thermal drying, the porous particles formed of albumin and solid carriers were dried in a vibm-fluidized bed dryn at different inlet air temperatures and different initial bulk porosities. Equations to predict temperature and moishrre content of panicles as well as the kinetics of biomass degradation were developed. The particle bulk porosity was incorporated into concentration-dependent moisture diffusivity model to estimate the erect of particle structure on product quality. The analysis of both calculated and experimental results indicates that the more porous structure promotes moisture diffusion, increases drying rate and finally improves the quality retention of bio-products. An extensive literature survey on quality retention issues during thermal drylng has been done.     

THE INFLUENCE OF TEMPERATURE ON SORPTION ISOTHERMS OF PROTEIN-CONTAINING MIXTURES

This paper presents a method for calculation of water sorption isotherms for multicomponent mixtures at different temperatures from mass fractions and sorption isotherms of components at a reference temperature. Additionally, Krischer's coefficients are required for the components. To compare experimental and calculated data, investigations on whey protein concentrates were carried out.