RELATIONSHIP BETWEEN INSTRUMENTAL AND SENSORY ANALYSIS OF TEXTURE AND COLOR OF POTATO CHIPS

The instrumental and sensory analysis of the texture and color of commercial potato chips were compared. The instrumental measurement was a puncture test with an Intron Universal Testing Machine, and the parameters used were fracture force, deformation and stiffness. The instrumental color quantification was a computerized video image analysis technique, and the color was expressed as L*a*b* values. Sensory evaluation of texture and color was performed by a sensory panel especially trained in evaluating potato chips. The sensory attributes were "hardness", "chewiness", "crunchiness", and "tenderness" for texture analysis, and "yellow color", "burnt aspect", "sugar colored aspect" and "transparency" for color analysis. The factor analysis of the sensory attributes indicated that texture can be divided into two principal components, one represented by "hardness", "crunchiness" and "chewiness", and the other by "tenderness" alone. The factor analysis of the color can be divided into two principal components, one including "yellow color" and "burnt aspect", and the other "sugar colored aspect" and "transparency". Discriminant analysis showed that "tenderness" and "crunchiness" could predict correctly over 90% of the data. Fracture force correlated well with all of the sensory attributes (R² > 0.76), and L* with the sensory color attributes (R² > 0.79). The "Tenderness" was the individual sensory attribute which had the highest correlation (R²= 0.95) with fracture force.     

ON THE LENGTH EFFECT OF THE HEAT DISPERSION PARAMETERS

Considerable attention has been paid to the dispersion of heat in fixed beds passed by a flowing gas. This is best documented by ample experimental evidence and correlations available in the literature. However, the results of individual studies differ often significantly. As a possible cause of the discrepancies have been put forth various experimental techniques and data processing methods (Gunn, 1970; Froment, 1972; Li and Finlayson, 1977), particularly the use of different mathematical models.

As a fact of considerable significance, however, remains the dependence of results on the geometry of the experiment. All parameters of the pseudohomogeneous one- and two-dimensional models have been found to depend on the length of the bed (Li and Finlayson, 1977; De Wasch and Froment, 1972; Bunell el al., 1949; Calderbank and Pogorski, 1957), while their values invariably decrease with the increasing length. In contrast, neither of the existing models predicts such a dependence, nor is there a satisfactory explanation for the phenomenon at hand.

The aim of this work has been to carry out experimental measurements of the effective radial thermal conductivity in a fixed bed passed by flowing air and to analyze in detail the length dependence of the results. The experiments consisted of measurement of the steady state outlet temperature profiles corresponding to a radially distributed inlet profile.     

New scintillation detector of backscattered electrons for the low voltage SEM

The new scintillation detector of backscattered electrons that is capable of working at primary beam energy as low as 0.5 keV is introduced. Low energy backscattered electrons are accelerated in order to generate a sufficient number of photons. Secondary electrons are deflected back by the energy filter so that the true compositional contrast of the specimen is obtained. The theoretical models of the detector function are described and first demonstration images are presented.     

Electrical impedance spectroscopy and electrical response in metal/non-metal systems

A new analysis of the electrical response of a macroscopic solid state system to an arbitrary electrical voltage input is presented. The results indicate that with a small, sinusoidal voltage input within the classical frequency range (ω < 10¹⁰Hz), the electrical response in spatially homogeneous systems mirrors first of all the static, spatial distribution of the mobile charge carrier density through the local electrical conductivity relaxation time. This enables any system, inclusive interface and electrical contact regions to be modelled by a simple, passive R, C electrical network, where each of the network elements has a very direct physical meaning. Ultra pure, single crystal silicon, pure polycrystalline silicon and Al-Al₂O₃-Au metal-insulator-metal (MIM) structure are used as illustrative examples.     

THE PHILOSOPHICAL FOUNDATIONS OF ALTERNATIVE SET THEORY*

This paper deals with philosophical fundamentals of Alternative Set Theory and its relation to classical mathematics. The key problem is a possibility to mathematize the phenomenon of horizon and the corresponding infinity. Serious criticism of classical set theory is given, especially in connection with its understanding of this phenomenon. The relation between classical and natural infinity (studied by AST) is presented and the difference between AST and Non-standard analysis is discussed. At the end, the fundamental notions of AST are briefly characterised, specifically that of sets, classes, semisets, and the extended universe. The encompassing of the vagueness (unsharpness) phenomenon by AST, and the concepts of static and dynamic AST are also discussed.     

CELL LOSS QUALITY OF SERVICE IN AN INTEGRATED TRAFFIC ATM NETWORK

This paper explores and evaluates several aspects of quality of service (QOS) in an integrated traffic ATM network. Specifically, we consider the relationships between service class definitions, usage parameter control (UPC) or policing of customer traffic, network resource allocation mechanisms, and specific network conditions under which realistic QOS limits on cell loss ratio (CLR) can be met. Traffic consists of a mixture of voice, video, image and data divided into two service classes for UPC and network resource allocation. The block oriented network simulator (BONeS) tool is used for performance evaluations. Limitations associated with evaluating very low CLR values (e.g. 10⁻⁸ and 10⁻⁶) via simulation are overcome by a hybrid simulation and extrapolation technique. It is found that these stringent QOS limits on CLR can be met for most traffic with the techniques used here, reasonable backbone trunk loads (75 per cent) and reasonable buffer sizes (200–250 cell buffers per queue). However, meeting similar limits for extremely bursty traffic (such as our image traffic model) would require extra care in network design and operation, including judicious segregation of traffic.     

Discrete events and general systems theory

A new formal approach to the qualitative modelling of general time systems is introduced. The formalism is suitable for general non-deterministic systems with non-numerically valued inputs and outputs, e.g. for discrete event systems. The following basic concepts of systems theory, observability, causality, determinism and interconnections of systems, are defined using an input-output approach to the modelling. The concept of the state is introduced as a secondary one. A general definition of the discrete event systems is given. Some fundamental properties of systems are proved. A real-time extension of the supervisory control problem given by Ramadge and Wonham is formulated. Seven examples are provided.