DESIGNING 2 POLE AND 2/4 POLE WINDINGS BY THE SIMULATED ANNEALING METHOD

ABSTRACT

The object of the present paper is to explore the possibility of using simulated annealing procedures to determine multi-speed three phase windings. It is limited to the very simple case of p/2p polarities. The program has yielded the very well known solutions; thus, research may proceed towards more difficult problems.     

Subspace model identification Part 2. Analysis of the elementary output-error state-space model identification algorithm

The elementary MOESP algorithm presented in the first part of this series of papers is analysed in this paper. This is done in three different ways. First, we study the asymptotic properties of the estimated state-space model when only considering zero-mean white noise perturbations on the output sequence. It is shown that, in this case, the MOESPl implementation yields asymptotically unbiased estimates. An important constraint to this result is that the underlying system must have a finite impulse response and subsequently the size of the Hankel matrices, constructed from the input and output data at the beginning of the computations, depends on the number of non-zero Markov parameters. This analysis, however, leads to a second implementation of the elementary MOESP scheme, namely MOESP2. The latter implementation has the same asymptotic properties without the finite impulse response constraint. Secondly, we compare the MOESP2 algorithm with a classical state space model identification scheme. The latter scheme, referred to as the CLASSIC algorithm, is based on the Ho and Kalman realization scheme and estimated Markov parameters. The comparison is done by a sensitivity study, where the effect is studied of the errors on the data on the calculated column space of the shift-invariant subspace. This study demonstrates that the elementary MOESP2 scheme is more robust with respect to the errors considered than the CLASSIC algorithm. In the third part, the model reduction capabilities of the elementary MOESP schemes are analysed when the observations are error-free. We demonstrate in which sense the reduced order model is optimal when acquired with the MOESP schemes. The optimality is expressed by the difference between the 2-norm of the errors on the state (or output) sequence of the reduced-order model and the 2-norm of the matrix containing the rejected singular values being as small as possible. The insights obtained in these three parts are evaluated in a simulation study, and validated in this paper. They lead to the assertion that the MOESP2 implementation allows identification of a compact, low-dimensional, state-space model accurately describing the input -output behaviour of the system to be identified, while making use of ‘perturbed’ input-output data. This can be done efficiently.     

Comparison theorems for set stability of differential equations

Set stability and uniform set stability of differential equations involve known specific bounds on solutions of the differential equations under consideration. Comparison theorems are presented giving sufficient conditions for these forms of stability. The conditions include the existence of a Liapunov-Like function and the set stability of a scalar differential equation. Examples are given to demonstrate the method.     

Nutritional Value of Veal Bone Hydrolysate

Industrial veal hydrolysate was produced enzymatically for possible use as a gelatin-replacing ingredient for human consumption. Protein digestibility and nutritional value were determined in vitro and in vivo. Net protein ratio (= 2.65) and true digestibility (= 80.3) were compared with gelatin and caseinate. Protein digestibility was determined by pH-stat method and cell dialysis. Amino acid composition including 4-hydroxyproline, allowed determination of connective tissue, amino acid score and protein digestibility corrected amino acid score. High correlation was found between true digestibility and pH-stat method (R²= 0.99). Meaty flavor and gelling properties of veal hydrolysate could make it useful for high-quality soups, sauces and gravies.     

Coalescence Index of Protein-Stabilized Emulsions

A simple method is proposed to estimate coalescence stability of protein-stabilized emulsions. Coalescence was accelerated through agitation and measured by change in emulsion turbidity over time. A coalescence index (CI) was determined and used to compare emulsions stabilized with casein, whey (WPI) and soy protein isolates (SPI). CI increased when stirring rate increased. Casein produced more stable emulsions, followed by WPI and SPI. High homogenization pressure increased coalescence stability of WPI and SPI-stabilized emulsions and decreased coalescence stability of casein-stabilized emulsions. Microscopic examination, showed agitation of the emulsion had clearly induced formation of large oil droplets which acted as coalescence nuclei.     

High temperature compression creep of aluminium nitride after immersion in molten stainless steel

The effect of immersion in molten steel on subsequent creep behaviour has been investigated in two AlN ceramics. Steady-state creep was not significantly affected but an enhanced initial creep rate was observed, especially when the surface layer had not been removed after immersion. In immersed samples, SEM revealed some open porosity and microcracks near the surface and particles containing steel constituents were found by TEM deep inside samples, in grain-boundary secondary phases. This revised version was published online in November 2006 with corrections to the Cover Date.     

Optimizing Procedure Calls for Delayed Non-local Execution Protocol

This work originated from the challenge to strengthen a C-like language compiler developed to support the compilation of sleepers, which are tools which allow complete access to the run-time stack in a delayed non-local execution protocol. Sleepers use a specialized form of procedure call, for which the gain in time execution and space memory allocation becomes a crucial need. These two objectives have been attained thanks to a methodology which generalizes the traditional distinction between tail-calls and normal-calls, introducing the orthogonal distinction between calls in which the calling environment is needed after the call site and calls in which it is not. These two dichotomies divide the space of calls into four classes. The strategy described in this paper is a simple and general framework which can be used to optimize the call-procedure statement in C compilers. The paper discusses optimization techniques appropriate to each class in turn, providing code details for SPARC and ALPHA processors.     

Carbon Dioxide and Global Change: Earth in Transition. - S.B.IDSO

The authors have proposed a generalisation of the J-CHART method [1] for a polyvalent modular drying system obtained by multiple simulation of thermal performance of two standard configurations: without recycling the air leaving the dryer, with 50% recycling of the air leaving the dryer and mixing with the air leaving the collectors.

This method, named as “GJ-CHART” is based on the use of charts or polynomial correlations which allows to determine the fraction of monthly average heating load supplied by solar energy and the fraction of monthly average economized energy as function of the two dimensionless parameters. These parameters are related to the standard collector parameters, the data of monthly average radiation, temperature and the estimates of drying loads, which by consequence, allows for a more general use.

The GJ-CHART method was developed for drying 27 kg of apple slices placed in single layers on the trays of the modular dryer. The temperature and the drying air flow rate are 60^°C and 0.09 kg s^-1 respectively. The drying time of a drying operation depends on the configurations of the system used, varying between 12 to 13 hours. According to the assumptions we used and the ways in which the calculations are done, this design method can be generalized to provide a mean for quick estimation of the long-term performance of the partially solar heated polyvalent modular drying system.

Les auteurs proposent, à l'aide de multiples simulations, une généralisation méthode J-CHART [I] de dimensionnement d'un système de séchage modulaire polyvalent valable pour les deux configurations suivantes: sans recyclage de l'air sortant du sèchoir; avec recyclage partiel (50%) et mélange avec l'air sortant des insolateurs.

Cette méthode, baptisée “GJ-ABAQUE”, est basée sur I'utilisation d'abaques ou des relations polynomials qui sen déduisent: ceux-ci permettent de déterminer la couverture solaire mensuelle et la fraction de chaleur de séchage économisée mensuelle à partir de deux couples de paramètres adimensionnels qui les caractérisent respectivement. Ces derniers font intervenir notamment les paramètres standard des insolateurs, les conditions climatiques du site, la surface de captation et la chaleur totale de I'opération de séchage, ce qui permet, par conséquent, une utilisation assez générale.

Les travaux ont porté sur le séchage de 27 kg de rondelles de pommes déposées en couche unique sur des claies, dans un module de séchage, lorsque la temperature de I'air asséchant est de 60^°C et son débit de 0,09 kg s^-1. La durée d'une opération de séchage varie, suivant la configuration retenue, de 12 à 13 heures.