Evaluation of reactive power meters in the presence of highharmonic distortion

Four reactive power meters, operating on different principles, were tested under nonsinusoidal conditions. Different definitions of the reactive power are discussed. Because the definition and meaning of the nonsinusoidal reactive power are still being actively debated, the readings of the tested meters were compared with four nonsinusoidal reactive powers and the first harmonic reactive power, to verify whether these readings can be interpreted as approximate measures of the different definitions. A digital instrument, programmed to measure each of these powers, was used as a reference     

Modulation of cisplatin chronotoxicity related to reduced glutathione in mice

Intracellular reduced glutathione (GSH) concentrations were measured according to the tissue sampling-time along the 24 h scale in male B6D2F1 mice. A significant circadian rhythm in GSH content was statistically validated in liver, jejunum, colon and bone-marrow (P < or = 0.02) but not in kidney. Tissue GSH concentration increased in the dark-activity span and decreased in the light-rest span of mice. The minimum and maximum of tissue GSH content corresponded respectively to the maximum and minimum of cisplatin (CDDP) toxicity. The role of GSH rhythms with regard to CDDP toxicity was investigated, using a specific inhibitor of GSH biosynthesis, buthionine sulfoximine (BSO). Its effects were assessed on both tissue GSH levels and CDDP toxicity at three circadian times. BSO resulted in a 10-fold decrease of the 24 h-mean GSH in kidney. However a moderate GSH decrease characterized liver (-23%) and jejunum (-30%). BSO pretreatment largely enhanced CDDP toxicity which varied according to a circadian rhythm. Although BSO partly and/or totally abolished the tissue GSH rhythms, it did not modify those in CDDP toxicity. We conclude that GSH have an important influence on CDDP toxicity but not in the circadian mechanism of such platinum chronotoxicity.     

A least mean-squared error approach to syntactic classification

The usual approach to numerical training in syntactic pattern recognition involves estimation of the production probabilities of stochastic context-free grammars. Here we describe a different approach, namely that of finding an LMSE discriminant hyperplane between sets of class samples in a space of ``structural indices' determined by a context-free grammar.     

A calibration system for evaluating the performance of harmonicpower analyzers

The paper describes a calibration system which is being used to evaluate the performance of harmonic power analyzers and related equipment. A method for verifying the software based calculations of the harmonic quantities obtained with the digital recorder of the calibration system is discussed. Test results of a harmonic power analyzer are also included     

Circadian rhythm in toxic effects of cystemustine in mice: relevance for chronomodulated delivery

We present a 76-year-old male patient with adhesive-type cholesteatoma and with metal foreign bodies which were shown to be located in the bony eustachian tube by computed tomography. He sustained a burn injury of the left tympanic membrane when he was struck by a bomb 52 years ago, during World War II. The cannonball fragments that entered the tympanic cavity were apparently transported to and stuck in the eustachian tube isthmus by mucociliary action after spontaneous closure of the tympanic membrane perforation. Persistent tubal obstruction due to the impacted foreign bodies and surrounding granulation tissue seems to have caused chronic adhesive otitis, leading to cholesteatoma which developed in the attic and mastoid antrum. No foreign bodies became visible after cholesteatoma removal by an intact canal wall technique in conjunction with anterior tympanotomy for wide exposure of the supratubal recess and the tympanic osteum of the eustachian tube. Therefore, anterior tympanotomy was further extended anteriorly to open the enlarged bony eustachian tube, allowing visualization and safe removal of two cannonball-fragments firmly impacted within it. We call this surgical approach to the bony eustachian tube "extended anterior tympanotomy". The transmastoidal accessibility of the bony eustachian tube produced by this technique should be assessed by preoperative computed tomography.     

Evaluation of low-frequency AC-DC difference of coaxially mountedthermal voltage converter

The paper describes results of measurements of AC-DC transfer difference of a coaxially mounted, thermal voltage converter. Results of experiments, conducted in the 1 kHz to 1 MHz frequency range, are compared with results of simulations, using a simplified model of the converter. AC-DC transfer difference contributions, originating in the input connector and elements of the coaxial enclosure, are presented     

International comparison of quantum AC voltage standards for frequencies up to 100 kHz

This paper presents results of an international comparison of two quantum AC voltage standards based on pulse-driven Josephson arrays. The two systems differ in several hardware and software characteristics as well as in the level of automation, features which can influence the accuracy of transferring the quantum-standard voltage value to a calibrated instrument. The comparison was performed at 100 mV, 20 mV and 12 mV, at frequencies between 2.5 kHz and 100 kHz. An electronically-aided thermal transfer standard was used as a travelling standard. At the most accurate voltage and frequency point, 100 mV at 2.5 kHz, both laboratories agreed to better than 1 part in 10⁶.     

The Systematic Errors of a Time-Division Power Converter under Sinusoidal and Nonsinusoidal Conditions

Systematic errors of an astable multivibrator based time-division active power converter are analyzed. Results of a computer simulation for sinusoidal and nonsinusoidal input signals are compared with test measurements of a standard converter. The paper shows that a conversion error of the power converter can be estimated from the harmonic content of the input waveforms.