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Electric motors are elementary drivers for various processes in countless applications concerning several areas of modern societies. This relevance can be mainly attributed to their high efficiency and robustness. However, due to their operating conditions, electric motors are subjected to different stresses that may lead to electromechanical damages, which, if not correctly detected, can cause irreversible failures and high repair costs. Moreover, damages in the different motor components reduce the motor efficiency since they increase machine losses. In this regard, the analysis of different machine signals has aided in diagnosing these failures; however, few systems can merge the information from relevant signals to identify a wide range of faults under different operating conditions. This article presents recent advances in the electric motor condition monitoring area, which have led to the development of a proprietary data fusion system (DFS) for automatic fault diagnosis. The DFS relies on the combined analysis of currents, stray magnetic fluxes, and infrared data, which can be measured in a noninvasive way by using simple and low-cost primary sensors. The DFS integrates conventional techniques based on stationary analysis (e.g., motor current signature analysis or MCSA) and a modern, robust methodology relying on the analysis of transient currents and fluxes, which has proven to yield high reliability for the final diagnosis while requiring a low computational burden. The article shows some results obtained when applying the system to actual machines, proving the capabilities of the developed methodology.

Rats normally prefer dilute oil suspensions over vehicle, but this preference can be abolished by exposing them to dilute oil suspensions during a period of food deprivation. In the first series of experiments, rats were given a choice of 0·5-0·9% triolein vs. vehicle for 4 consecutive days each week for 3 weeks. Food was available ad libitumon days 1, 2 and 4; no food was available on day 3. Preference for oil suspension dropped sharply after, but not during, each occasion that food was withheld. Similar experiments using starch, Polycose®, or sucrose did not show comparable deprivation-induced changes in preference.

The literature on the genetics of feeding and drinking, and the genetic methods that will be useful for future research, are described. Four subjects which have been studied most thoroughly by geneticists are discussed: intake of plain water, intake of and preference for flavored water, body weight and food intake regulation when confronted with high-fat diets, and excess body weight. Although a moderate number of strain comparisons and a few genetic analyses have been reported, relatively little is known about the nature of genetic influences. The only major exception is the study of obese mutants where considerable progress has been made in elucidating the physiological mechanisms which produce overeating in such animals. However the study of the behavioral changes in obese mutants is still at an early stage.

Studies were undertaken to analyze the role of moisture content of foods in producing dietary obesity. Female CD rats consumed more energy when offered a sucrose solution and plain water to drink than when they were only given plain water, regardless of the sugar content of their diet (0–65%). This suggested that the overeating that commonly occurs when sucrose solutions are offered may not be due to sucrose per se. In subsequent experiments, rats were fed modified AIN-76 diets high in sucrose, starch or fat for 28–42 d. For some rats, the diet was liquefied by adding water to make a 32% suspension. Plain drinking water was always available. Rats fed high carbohydrate liquid diets, with or without solid diet, consumed 8–15% more energy than rats fed solid diet only. Rats fed liquid diets also gained 43–206% more weight than did rats fed solid diets. Analysis of carcass composition revealed that the liquid diets increased body fat. For high fat diets, the results were more complicated. Addition of water to a low cellulose, high fat diet did not increase adiposity, whereas addition of water to a high cellulose, high fat diet did increase adiposity. These results suggest that the obesity-inducing effects of feeding sugar solutions or cafeteria diets may be due, in part, to the high water content of these foods.

Adult rats (12 wk of age) fed a wet, high starch diet consumed more energy, gained more weight, and had more carcass fat than rats fed the same diet in a dry form. In contrast, juvenile rats (3.5 wk of age) did not consume more energy, gain more weight, or become fatter when fed the wet, high starch diet than when fed the same diet in dry form. Although rats of both age groups fed high fat diets consumed more energy than rats fed high starch diets, the effect of the high fat diets was much smaller in juvenile than in adult rats. The level of dietary protein (20 vs. 8%) in the diets did not interact with diet type, but juvenile rats fed low protein diets gained less weight than juvenile rats fed standard protein diets. Additional experiments showed that juvenile rats fed a 20% protein diet were capable of increasing fluid intake and energy intake when given sweetened water or insulin, respectively. Thus, low susceptibility to dietary hyperphagia in juvenile rats cannot be explained by assuming that juvenile rats already eat as much as they can. These data are consistent with the possibility that developmental changes in taste responsiveness may contribute to this effect of age.

Rats fed wet diets containing saccharin consumed 12–14% more energy and gained 24–55% more weight than rats fed the same diets without saccharin. Saccharin-induced stimulation of intake was usually not so pronounced during the first week as during subsequent weeks of each experiment. Similar results were obtained using diets high in starch and fat. However, these effects could be obliterated by simply exposing the rats to unsweetened (plain) diet or to saccharin in water for several days before the sweetened diets were introduced. Furthermore, although stimulation of intake by saccharin was observed with diets containing 80% water, no such effect was observed with a diet containing 60% water. Rats given low-energy sweetened water in addition to their 80% water diet consumed substantially more fluid but not more or less energy than rats given unsweetened water. Preference tests suggest that saccharin increases diet palatability only very slightly; this finding is one of several observations suggesting that stimulation of intake by saccharin cannot be interpreted in terms of increased diet palatability. These results suggest that dietary hyperphagia results from the interaction between innate and learned responses to the taste of foods. Osmotic factors did not seem to exert a major influence in these experiments.