Search results for "AIC"

Nonlinear vibrations of elastic beams with external general visco-elastic devices

2011

Vibration damping for slender beams is achieved by applying devices at external points. The latter consist of general single visco-elastic springpot elements. An approximate nonlinear boundary value problem is found in frequency domain that holds for moderately large vibrations or for linear beams with external nonlinear devices, both in the vicinity of primary resonances. The interaction force of a so-called springpot element is expressed as a sum of two separate forces: the first develops due to the external loading function at the device location, and the second contribution arises due to an imposed time-harmonic support excitation with no other external forces acting on the structure. F…

Vibrational Spectra of Polyatomic Molecules through an Algebraic Approach

1987

The study of molecular oscillators may be performed with algebraic methods based upon dynamical chains and their realization in terms of boson operators. From the dynamical algebra U(p+1) for p equivalent oscillators, associated with stretching modes, the local, pseudo-normal and normal limits are obtained through appropriate subgroup chains and various realizations of the U(p+1) generators. Similar technics can be applied to bending modes. Application to XY4 molecules will be presented.

Rovibrational interactions in the local-mode limit. The (n000) stretching overtone bands of spherical tops.

1993

Por un debate público mundial desde la multiculturalidad y la simetría de reconocimientos recíprocos de las diferencias

1999

1993

In a new theoretical approach the separation of a pair of chain molecules (measured thermodynamically by the second osmotic virial coefficient A2) is treated as a two-step process: In the first step the molecules are detached from each other by the addition of solvent—keeping their dimensions constant—and in the second step the now isolated coils are allowed to relax into their equilibrium dimensions. For the description of the second step, in which only segments belonging to one molecule take part, an intra-molecular interaction parameter is introduced on the basis of the intrinsic viscosity. The present two-parameter approach yields A2 = A + σ M−(1−a) for the dependence of A2 on the molec…

“Versus aurei” nella poesia di Walahfrido Strabone

2018

Walahfrido Strabone può essere senz’altro considerato il più importante poeta dell’età carolingia. Vissuto fra l’809 e l’849, egli ha composto alcuni poemetti di vario genere e di diversa tipologia (Visio Wettini, Hortulus, Vita Mammae, Versus de beati Blaithmaic vita et fine, Versus de imagine Tetrici), nonché una gran quantità di carmina che rivelano la sua grande perizia metrica e versificatoria. In questa postilla, dopo una prima parte dedicata allo status degli studi sullo scrittore carolingio, sulla sua vita e sulla sua produzione poetica, si dà particolare risalto a un artificio versificatorio da lui praticato, ossia il ricorso al "versus aureus", la cui frequenza e la cui incidenza …

A Visual Introduction to Cubic Surfaces Using the Computer Software Spicy

2003

At the end of the 19th century geometers like Clebsch, Klein and Rodenberg constructed plaster models in order to get a visual impression of their surfaces, which are so beautiful from an abstract point of view. But these were static visualizations. Using the computer program Spicy 1, which was written by the second author, one can now draw algebraic curves and surfaces depending on parameters interactively.

Hypoxia Positively Regulates the Expression of pH-Sensing G-Protein–Coupled Receptor OGR1 (GPR68)

2016

Background & Aims: A novel family of proton-sensing G-proteinâcoupled receptors, including ovarian cancer G-proteinâcoupled receptor 1 (OGR1) (GPR68) has been identified to play a role in pH homeostasis. Hypoxia is known to change tissue pH as a result of anaerobic glucose metabolism through the stabilization of hypoxia-inducible factor-1α. We investigated how hypoxia regulates the expression of OGR1 in the intestinal mucosa and associated cells. Methods: OGR1 expression in murine tumors, human colonic tissue, and myeloid cells was determined by quantitative reverse-transcription polymerase chain reaction. The influence of hypoxia on OGR1 expression was studied in monocytes/macrophages and…

A Hybrid Power Supply with Variable Speed Drive for Automatically Move Irrigation Equipment: Margin of Feasibility

2021

Center pivot irrigation systems are widely used in agriculture. Their water pumping systems are primary energy consumers. The use of photovoltaic power plants and variable speed drives of electric motors can reduce energy costs. The purpose of this study is to determine the feasibility of integrating variable speed drives and photovoltaic modules into water pumping systems. A novel architecture of a pumping system was suggested. Its features are no battery backup and the sale of electricity into the grid.

Performance analysis of photovoltaic powered dc motor — Propeller system

2015

The application of autonomous directly photovoltaic (PV) powered electro-mechanical has received increasing attention for different applications (e.g. PV water pumping, PV powered cooling of arid climate greenhouses, solar vehicles etc). The PV array output is a nonlinear and time-dependent power supply that varies with solar intensity and cell temperature, so the performance characteristics of the directly PV-powered DC motor — propeller system are very different than when powered by a constant DC voltage. The focus of this work is to do performance analysis of directly PV-powered DC motor — propeller system. Through performance evaluation, it has been observed that power transfer matching…