Energy functions for dissipativity-based balancing of discrete-time nonlinear systems

Most of the energy functions used in nonlinear balancing theory can be expressed as storage functions in the framework of dissipativity theory. By defining a framework of discrete-time dissipative systems, this paper presents existence conditions for their discrete-time energy functions along with algorithms to find them based on dynamic optimization problems. Furthermore, the important case of the nonlinear discrete-time versions of the controllability and observability functions, its properties and algorithms to find them are presented. These algorithms are illustrated with linear and nonlinear examples.     

Fracture of glass in tensile and bending tests

To fully characterize the mechanical behavior of ceramics, it is useful to study their response to both tensile and bending tests. In this investigation, a quantitative comparison is made between tensile and bending results from (circularly) cylindrical glass rods of borosilicate glass and of fused silica. These experimental results show that in each material, the Weibull exponentm is approximately the same for both types of test. The fractured samples clearly showed that all failures initiated at surface-located flaws. The stress level at which the probability of fracture in tension equals 50 Pct was determined; the maximum tensile stress for 50 Pct probability of fracture in bending was also determined. The ratio of these two stresses was predicted previously from simple, theoretical considerations based upon the applicability of the Weibull function and on the distribution of defects in the specimens. This theoretical result is inconsistent with the experimental observations in view of the fractography. Therefore, it is concluded that failure in the materials tested is not satisfactorily described by Weibull statistics.     

Hull-less Barley Varieties: Storage Proteins and Amino Acid Distribution in Relation to Nutritional Quality

Barley (Hordeum vulgare L.) has had an important impact on human nutrition. Hull-less barley is a genetically improved type that has been widely used in recent years. Six Brazilian hull-less barley varieties (IAC-IBON 214-82; IAC 8612-421; IAC 8501-31; IAC 8501-12; IAPAR 39-ACUMAI; IAC 8501-22) were analyzed for storage protein constituents, amino acid contents, and similarity among the hull-less barley varieties. Albumins, globulins, prolamins I and II, and glutelins were extracted and separated by SDS-PAGE. The total protein amino acid contents of the flour were also determined for each variety by TLC and HPLC. Variations in intensity and appearance and disappearance of protein bands were observed among the varieties suggesting genetic variability. However, the amino acid profile did not indicate any major variations in the amino acid concentrations. The high lysine and threonine total concentrations detected in the seeds of the hull-less barley varieties encouraged an investigation into the regulation of amino acid metabolism and storage protein synthesis.     

Hardware and software architecture for power quality analysis

This paper presents a novel concept for power quality hardware and software architecture. Software tools related to detection, classification and characterization of power quality events can be integrated into a Distribution Control Center in which the interconnection between different subsystems is being carried out through the Internet allowing flexibility to the system. This system is implemented using wavelet analysis applied in all proposed algorithms. Different power quality events are taken as examples to illustrate the capabilities of the proposed method. The obtained results reveal that the proposed architecture is feasible to be implemented as an integral part of a control center system.The proposed system has the property of fast and accurate detection and classification of any power quality disturbance event and introduces a new PQ index determination that allows characterizing any type of disturbance including the non-periodic signals.     

Qualitative features of matrix pencils and DAEs arising in circuit dynamics

The dynamical behaviour of nonlinear electrical circuits is usually modelled in the time domain by differential-algebraic equations (DAEs). The differential-algebraic formalism drives qualitative analyses based on linearization to a matrix pencil setting. In this context, the present paper performs a spectral analysis of matrix pencils and DAEs arising in nonlinear circuit theory. Specifically, the non-singularity, hyperbolicity and asymptotic stability of equilibria are addressed in terms of circuit topology. The differential-algebraic framework puts the results beyond those already known for state-space models, unfeasible in many actual problems. The topological conditions arising in this qualitative study are proved independent of those supporting the index, and therefore they apply to both index-1 and index-2 configurations. The approach illustrates how graph theory, matrix analysis and DAE theory interact in the dynamical study of nonlinear circuits.     

Microstructural and textural characterization of a hot-rolled IF steel

The present paper reports the experimental results on the microstructural and textural characterization of a hot-rolled IF steel. The IF steel was hot-rolled in multiple passes in the austenitic field (1,070 °C) followed by air-cooling. SEM, TEM, and LOM were used to image the microstructure of the material. The global texture was determined by X-ray diffraction (XRD) technique. The mesotexture of selected regions was investigated by electron backscatter diffraction (EBSD). Results show the presence of a diffuse (nearly random) and weak texture in the hot-band that consists of recrystallized polygonal grains and subgrains. The fraction of boundaries with misorientations comprised in the interval 2° ≤ ψ < 15° was found to be lower than 5%. It can be concluded that these low angle boundaries and the presence of subgrains can be associated to the existence of a few areas softened by recovery during or after hot rolling in austenitic field.     

Experiments of Fast Learning with High Order Boltzmann Machines

This work reports the results obtained with the application of High Order Boltzmann Machines without hidden units to construct classifiers for some problems that represent different learning paradigms. The Boltzmann Machine weight updating algorithm remains the same even when some of the units can take values in a discrete set or in a continuous interval. The absence of hidden units and the restriction to classification problems allows for the estimation of the connection statistics, without the computational cost involved in the application of simulated annealing. In this setting, the learning process can be sped up several orders of magnitude with no appreciable loss of quality of the results obtained.     

2-Hydroxypropyl-beta-cyclodextrin enhances phorbol ester effects on glucose transport and/or protein kinase C-beta translocation to the plasma membrane in rat adipocytes and soleus muscles

In rat adipocytes and soleus muscles, 2-hydroxypropyl-beta-cyclodextrin (CD) was found to have a relatively small or no effect on basal or insulin-stimulated hexose uptake, but markedly enhanced hexose uptake effects of phorbol esters and/or diacylglycerol. In rat adipocytes, the CD-induced enhancement of hexose uptake during concurrent phorbol ester treatment was not associated with an increase in GLUT4 glucose transporter translocation to the plasma membrane, which was stimulated comparably by insulin and phorbol esters. Moreover, CD appeared to activate or facilitate the activation of glucose transporters subsequent to their translocation to the plasma membrane during ongoing phorbol ester treatment. In rat adipocytes, CD also enhanced the translocation of protein kinase C (PKC)-beta to the plasma membrane during the action of phorbol esters, which alone had little or no effect on this specific PKC translocation. Although it is uncertain how CD alters the function of plasma membranes to enhance the translocation of PKC-beta to, and the activation of glucose transporters within, this subcellular fraction during phorbol ester treatment, our findings provide direct support for a two-step model in the activation of glucose transport. In addition, it seems clear that, at least in some cell types, simple phorbol ester treatment does not necessarily serve as a ubiquitous activator of all activable PKC pools and all potential PKC-mediated responses.     

Heat and Moisture Transfer in Wet Sand Exposed to Solar Radiation—Models and Experiments Concerning Buried Objects

One promising method of locating buried objects, such as land mines, is to use optical systems for detecting contrasts in surface temperature. With enhanced knowledge about the interacting physical processes behind these temperature contrasts, it is possible to improve detection precision. In such a context, moisture movement in the soil and moisture evaporation from the surface have been found to be of particular interest. This study was based on indoor experiments on wet and dry sand exposed to radiation from a solar panel. Simulations of heat and moisture transfer conducted with a one-dimensional model are also presented for the experiments. The calculations were successful in accurately predicting surface temperatures for both wet and dry sand, making it possible to predict surface temperatures under different conditions. These findings will contribute to increasing the probability of successful detection of buried objects under real conditions using optical methods.     

Electrical heat tracing: international harmonization-now and in thefuture

In the past, electrical heat tracing has been thought of as a minor addition to plant utilities. Today, it is recognized as a critical subsystem to be monitored and controlled. A marriage between process, mechanical, and electrical engineers must take place to ensure that optimum economic results are produced. The Internet, expert systems, and falling costs of instrumentation will all contribute to more reliable control systems and improved monitoring systems. There is a harmonization between Europe and North America that should facilitate design and installation using common components. The future holds many opportunities to optimize the design