Speculative Thread Framework for Transient Management and Bumpless Transfer in Reconfigurable Digital Filters

There are many methods developed to mitigate transients induced when abruptly changing dynamic algorithms such as those found in digital filters or controllers. These "bumpless transfer" methods have a computational burden to them and take time to implement, causing a delay in the desired switching time. This paper develops a method that automatically reconfigures the computational resources in order to implement a transient management method without any delay in switching times. The method spawns a speculative thread when it predicts if a switch in algorithms is imminent so that the calculations are done prior to the switch being made. The software framework is described and experimental results are shown for a switching between filters in a filter bank.Comment: 6 pages, 7 figures, to be presented at American Controls Conference 201

Analysis and design of large space structures with nonlinear joints

Issued as Final report, Project no. E-25-62

Application of the Probabilistic Dynamic Synthesis Method to the Analysis of a Realistic Structure

The Probabilistic Dynamic Synthesis method is a new technique for obtaining the statistics of a desired response engineering quantity for a structure with non-deterministic parameters. The method uses measured data from modal testing of the structure as the input random variables, rather than more "primitive" quantities like geometry or material variation. This modal information is much more comprehensive and easily measured than the "primitive" information. The probabilistic analysis is carried out using either response surface reliability methods or Monte Carlo simulation. A previous work verified the feasibility of the PDS method on a simple seven degree-of-freedom spring-mass system. In this paper, extensive issues involved with applying the method to a realistic three-substructure system are examined, and free and forced response analyses are performed. The results from using the method are promising, especially when the lack of alternatives for obtaining quantitative output for probabilistic structures is considered

Application of the Probabilistic Dynamic Synthesis Method to Realistic Structures

The Probabilistic Dynamic Synthesis method is a technique for obtaining the statistics of a desired response engineering quantity for a structure with non-deterministic parameters. The method uses measured data from modal testing of the structure as the input random variables, rather than more "primitive" quantities like geometry or material variation. This modal information is much more comprehensive and easily measured than the "primitive" information. The probabilistic analysis is carried out using either response surface reliability methods or Monte Carlo simulation. In previous work, the feasibility of the PDS method applied to a simple seven degree-of-freedom spring-mass system was verified. In this paper, extensive issues involved with applying the method to a realistic three-substructure system are examined, and free and forced response analyses are performed. The results from using the method are promising, especially when the lack of alternatives for obtaining quantitative output for probabilistic structures is considered

Development of a Probabilistic Component Mode Synthesis Method for the Analysis of Non-Deterministic Substructures

Standard methods of structural dynamic analysis assume that the structural characteristics are deterministic. Recognizing that these characteristics are actually statistical in nature, researchers have recently developed a variety of methods that use this information to determine probabilities of a desired response characteristic, such as natural frequency, without using expensive Monte Carlo simulations. One of the problems in these methods is correctly identifying the statistical properties of primitive variables such as geometry, stiffness, and mass. This paper presents a method where the measured dynamic properties of substructures are used instead as the random variables. The residual flexibility method of component mode synthesis is combined with the probabilistic methods to determine the cumulative distribution function of the system eigenvalues. A simple cantilever beam test problem is presented that illustrates the theory

Probabilistic Component Mode Synthesis of Nondeterministic Substructures

Standard methods of structural dynamic analysis assume that the structural characteristics are deterministic. Recognizing that these characteristics are actually statistical in nature researchers have recently developed a variety of methods that use this information to determine probabilities of a desired response characteristic, such as natural frequency, without using expensive Monte Carlo simulations. One of the problems in these methods is correctly identifying the statistical properties of primitive variables such as geometry, stiffness, and mass. We present a method where the measured dynamic properties of substructures are used instead as the random variables. The residual flexibility method of component mode synthesis is combined with the probabilistic methods to determine the cumulative distribution function of the system eigenvalues. A simple cantilever beam test problem is presented that illustrates the theory

Peeling of Long, Straight Carbon Nanotubes from Surfaces

The adhesion of long, straight, single-walled carbon nanotubes to surfaces is examined usingmultidimensional force spectroscopy. We observed characteristic signatures in the deflection and frequency response of the cantilever indicative of nanotube buckling and slip-stickmotion as a result of compression and subsequent adhesion and peeling of the nanotube fromthe surface.The spring constant and the elastic modulus of the SWNT were estimated from the frequency shifts under tension. Using elastica modeling for postbuckled columns, we have determined the static coefficient of friction for the SWNT on alkanethiol-modified gold surfaces and showed that it varies with the identity of the monolayer terminal group.Fil: Barker, Kane M.. Georgia Institute of Technology. School of Chemistry and Biochemistry; Estados UnidosFil: Poggi, Mark A.. Georgia Institute of Technology. School of Chemistry and Biochemistry; Estados UnidosFil: Lizarraga, Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; Argentina. Georgia Institute of Technology. School of Chemistry and Biochemistry; Estados UnidosFil: Lillehei, Peter T.. NASA Langley Research Center. Advanced Materials and Processing Branch; Estados UnidosFil: Ferri, Aldo. Georgia Institute of Technology. George W. Woodruff School of Mechanical Engineering; Estados UnidosFil: Bottomley, Lawrence A.. Georgia Institute of Technology. School of Chemistry and Biochemistry; Estados Unido

Libertà economiche e libertà politiche. Riforma dell'impresa e riforma dello stato

Relazioni del Convegno "Libertà economiche e libertà politiche. Riforma dell'impresa e riforma dello Stato" svoltosi alla Fondazione Agnelli, 17 e 18 giugno 1977.- Sommario #4- Presentazione #5- Introduzione al Convegno, Aldo Sandulli #6- Decentramento economico e coordinamento pubblico in Italia, Guido Carli #6- L’impresa come modello organizzativo tipico, Giuseppe Guarino #18- L’evoluzione del fenomeno imprenditoriale: conservazione dell’autonomia e dell’economicità dell’impresa nell’adeguamento della sua struttura organizzativa, Giuseppe Ferri #42- L’impresa e la riforma dello Stato, Umberto Agnelli #5

Peptide Fractions Obtained from Rice By- Products by Means of an Environment- Friendly Process Show In Vitro Health-Related Bioactivities

Recently, the isolation of new health-related bioactive molecules derived from agro-food industrial by-products by means of environment-friendly extraction processes has become of particular interest. In the present study, a protein by-product from the rice starch industry was hydrolysed with five commercial proteolytic enzymes, avoiding the use of solvents or chemicals. The digestion processes were optimised, and the digestates were separated in fractions with four different molecular weight ranges by using a cross-flow membrane filtration technique. Total hydrolysates and fractions were tested in vitro for a wide range of biological activities. For the first time rice-derived peptides were assayed for anti-tyrosinase, anti-inflammatory, cytotoxicity and irritation capacities. Antioxidant and anti-hypertensive activities were also evaluated. Protamex, Alcalase and Neutrase treatments produced peptide fractions with valuable bioactivities without resulting cytotoxic or irritant. Highest levels of bioactivity were detected in Protamex-derived samples, followed by samples treated with Alcalase. Based on the present results, a future direct exploitation of isolated peptide fractions in the nutraceutical, functional food and cosmetic industrial fields may be foreseen